ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (6,549)
  • 1990-1994  (6,549)
  • 1985-1989
  • 1960-1964
  • 1950-1954
  • 1993  (6,549)
  • Electrical Engineering, Measurement and Control Technology  (6,549)
Collection
  • Articles  (6,549)
Years
  • 1990-1994  (6,549)
  • 1985-1989
  • 1960-1964
  • 1950-1954
Year
Journal
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1182-1186 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The design and development of equipment for remote transducer output signal delivery is described which is based on a fiber-optic transmission-reception system employing subcarrier angular modulation for true direct current coupling, high linearity, and low noise behavior. Also, a fiber-based digital uplink for controlling the remote transmitter is presented which provides gain/attenuation programming, calibration signal insertion, battery test, and turn on/stand-by, both manual and automatically using and embedded computer controller. Performance measurements are given.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1614-1621 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A system which enables fast and reliable measurements of the dielectric constant over continuous microwave frequency ranges for both solid and liquid low-loss materials is described. The main thrust of this work is the application of the open-ended coaxial-line probe technique, which has been used previously for soft biological materials, to low-loss solid samples. Using the instrumentation and procedure presented here, the dielectric constant for low-loss solids can be measured absolutely to ±2%–3% with routine care. The uncertainty can be reduced by about a factor of 2 by averaging several measurements. It is also smaller for liquid samples. This application features the use of relatively simple and readily available microwave components. Also, it is shown that a simple empirical relationship can be used to obtain the bulk dielectric constant from samples of a material in the form of thin slabs. The experimental results which are presented here for kapton, Teflon, Corning glass No. 0211, soda lime glass, magnesium oxide, sapphire, silicon, alumina, and lanthanum aluminate, as well as carbon tetrachloride, compare favorably with existing literature values.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1622-1626 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: This work addresses the effect of finite sample thickness on microwave dielectric constant measurements for thin, planar, low-loss samples using the open-ended coaxial-line probe method. Detailed measurements of the dielectric constant were carried out on a wide range of thicknesses of air samples which were backed by infinitely thick teflon and alumina dielectric media. The measurements were made at room temperature for various (50 Ω) coaxial-line dimensions, microwave frequencies 4–8 GHz, and power levels near a fraction of a mW. The results provide strong support for previously published theoretical calculations based on a boundary value problem which uses a spectral domain formulation for the aperture fields. From thin, planar samples, values of 10.4±0.5 and 25.9±1.3 were obtained at 5 GHz and 300 K for the bulk dielectric constant of MgO and LaAl2O3, respectively. The applicability of a simple empirical model based on an exponential fit is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1636-1640 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In this paper the authors describe the construction and operation of a conductivity setup for high-temperature measurements. In the new conductivity equipment a direct current input signal and a high performance computer-controlled air oven were employed to measure the electrolyte conductance of dilute NaOH aqueous solutions up to 150 °C.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1644-1651 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A high-voltage variable resistor was designed, built, and implemented to modify an ion-energy spectrometer for the study of ion–atom collisions in which the projectiles change charge. The resistor is remotely switchable from 0 to 2050 MΩ and has a voltage rating of 200 kV. The design criteria and the electrical and mechanical details of the apparatus are discussed. The design and construction of an ancillary device, comprising two precision resistive-divider voltmeters, are also discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1657-1658 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Pressure sensitive capacitance of laser-induced chemical vapor deposition processed nanosized silicon nitride has been studied. It is found that the capacitance varies linearly with the pressure and its sensitivity is as high as 2.64 pf/Torr. The capacitance pressure sensitivity results from the huge interfaces and microvoids existing in the nanomaterials.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1663-1664 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A time-gated gain cell has been demonstrated as a method for producing single-longitudinal-mode output from a pulsed transverse, electric, atmospheric (TEA) carbon dioxide laser. The gain cell is operated as an oscillator during the time between the laser pulses and is rapidly dropped below threshold during the TEA pulse output to avoid degradation of the gain-switched spike in the laser pulse. Standard dither-stabilization techniques can be used during the time between the laser pulses (cw oscillation) to position the output coupler for single-mode operation and frequency stabilization while the gain cell is operated above threshold.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1105-1130 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The technology of high-resolution focused ion beams has advanced dramatically in the past 15 years as focusing systems have evolved from laboratory instruments producing minuscule current densities to high current density tools which have sparked an important new process: direct micromachining at the micrometer level. This development has been due primarily to the exploitation of field emission ion sources and in particular the liquid-metal ion source. Originally developed in the early 1960's as a byproduct of the development of electrostatic rocket engines, the liquid-metal ion source was adapted for focused beam work in the late 1970's, when it was demonstrated that submicrometer focused ion beams could be produced with current densities greater than 1 A cm−2. Ions can be produced with liquid-metal ion sources from elements including Al, As, Au, B, Be, Bi, Cs, Cu, Ga, Ge, Fe, In, Li, P, Pb, Pd, Si, Sn, and Zn. In the past decade, focused ion beam systems with liquid-metal ion sources have had a significant impact on the semiconductor industry as they were applied to new and greatly improved methods of failure analysis, as well as circuit repair and modification, in situ processing, and lithographic mask repair. This article discusses field emission ion sources, high-resolution ion focusing systems, and means for analyzing their performance. A number of technologically interesting and useful applications are also discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1330-1336 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The investigation of the servo control of the position of the bottom mass in a balanced two-stage pendulum vibration isolation system is reported. Experimental results for a simple prototype system and predictions based on a model presented in this paper are in good agreement. The application of such a system to a high-sensitivity laser interferometric gravity wave detector is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1347-1350 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A rotating piezoelectric device, which uses the so-called slip-stick mechanism for micropositioning is presented. The device is especially designed for use in point-contact experiments at very low temperatures in high magnetic fields. Two typical applications are presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1351-1354 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have developed an accurate, inexpensive translator utilizing the thermal expansion of an electrically heated wire. The resistance of the wire, measured in a Wheatstone bridge, provides a readout of the length of the wire based on its temperature coefficient of resistance.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1362-1363 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Two, inexpensive, easily constructed vessels are described which can be used to prepare and deliver measured volumes of parts per million concentrations of gaseous mixtures.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1091-1092 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An apparatus was built to collect simultaneous gravimetric and Fourier transform infrared sorption/desorption data on self-supporting clay films in a controlled-environment cell. This apparatus enables the masses of several sorbed species to be continuously monitored in situ. Its primary purpose is to characterize physisorption and chemisorption of arenes on clays.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1292-1295 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe a method for measuring and controlling the temperature of thin ceramic plates which are used as substrates for the deposition of thin films in high vacuum. The ceramic plates have an embedded platinum resistor which acts as both heating element and thermometer. The temperature of the substrate is controlled by an electronic feedback circuit. This arrangement enables accurate measurements of the thin-film temperature. In addition, the system has a fast response time and excellent long-term temperature stability. We describe an application where the temperature control system is combined with ac resistance measurements to study the kinetics of a solid-state interdiffusion reaction in Ni-Zr multilayers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1309-1318 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have designed and constructed a sealed, temperature-controlled Couette-type shear cell which allows us to carry out in situ synchrotron x-ray scattering studies of the nonequilibrium structures of complex fluids under flow, probing lengths ranging from the nanometer to the semimacroscopic micron scale. The sealed design allows the cell to be tilted, facilitating the scanning of all directions in reciprocal space. In contrast to existing neutron shear cells, we access the shear plane containing the velocity and the velocity gradient. The temperature control of the cell enables us to carry out phase transition studies far from equilibrium. The complex fluid systems which may be studied with this cell include thermotropic and lyotropic liquid crystals, microemulsions, and polymeric fluids. Recent results on the nematic and smectic-A phases of a liquid crystal, and the disordered bicontinuous L3 phases of surfactant membranes in the vicinity of the ordered lamellar Lα phase under flow, are presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1319-1323 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: For detection of weak signals, and for use on ultralow temperature experiments, it would be useful to have a robust superconducting quantum interference device (SQUID) amplifier that works below 1 K. We report on a test of a commercial SQUID amplifier that has lower noise than others we have tested, and works well while attached to a 50-mK chamber. The SQUID noise was improved only modestly when cooled from 4 K to 50 mK. The best energy resolution measured was 2200 (h-dash-bar).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1342-1346 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The essential construction features of a piston actuated shock tube are described, and its advantages relative to the conventional use of diaphragm ruptures for shock initiation are listed. Typical operational parameters are presented to illustrate the levels of reproducibility achieved. Tests with He and N2 drivers into ∼99% Ar (1.0%–0.1% reagent) covered shock speeds from 1.539±0.002–0.8143±0.002 mm/μs, corresponding to 2390–847K incident shock temperatures. Application of this tube for recording postshock front density gradients of the endoergic dissociation of ethane and the exoergic condensation of iron atoms via the laser–Schlieren technique is described.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1358-1359 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An improved, spring-loaded thermocouple rake, suitable for studying flame structure, has been designed. This design keeps the thermocouple under tension thereby ensuring that the thermocouple does not droop due to the thermal expansion of the sensing wire when inserted in the flame. The present design allows the usage of thermocouple wire as small as 0.0508 mm and relative ease in changing thermocouple wire.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1360-1361 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A quartz tube is propelled horizontally along a quartz track by the stick-slip inertial slider method, activated by the longitudinal mode of a piezoelectric tube mounted inside the quartz tube. Two-dimensional motion is achieved by rotation of the quartz tube, activated by the bending mode of the piezo. With a sample attached to the quartz tube, the device is an excellent replacement for the electrostatic-clamp type of walker used as the coarse approach mechanism in scanning probe microscopes (SPMs). Alternatively, by attaching the tip (or sample) to the piezo tube, the device can function as a very simple SPM in which the same piezo tube is used for coarse approach and for scanning. The device performs reliably in air and high vacuum, and is ultrahigh vacuum compatible. Step sizes from 10 to 1000 nm, and speeds up to 0.2 mm/s are possible.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1367-1368 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A simple technique for measuring the relative extension or response of a piezoelectric tube as a function of frequency is presented. The method clearly identifies resonant modes of the system. This information is useful in tuning feedback control systems in scanned probe microscopes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1010-1013 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A dispersion interferometer for measurements of line plasma density has been developed with a sensitivity 〈ne l〉min = 1013 cm−2 and a temporal resolution of 10 μs. The main advantages of the interferometer are compactness and minimal sensitivity to vibrations. The interferometer does not require specific vibration isolation structure and can be mounted directly on the working chamber of the plasma device. The use of short-wave radiation (λ=1.06 μm) eliminates the influence of refraction and enables one to use quartz windows, which are the most resistant to neutron and gamma radiation. The above-mentioned advantages have been successfully demonstrated in a gas-dynamic trap experiment. These properties make the dispersion interferometer a very attractive diagnostic tool for large tokamaks.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1014-1020 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A high throughput, shielded, multichannel, extreme ultraviolet (XUV) spectrograph to be used for plasma diagnostics was built. The instrument uses seven hollow fibers to transport the radiation by multiple grazing incidence reflections from the tokamak port through the instrument's shield to the spectrometer entrance slit. In this way, the ratio of background radiation streaming through the entrance slit to XUV flux is reduced by a factor of at least 2500. The seven hollow fibers provide seven channels corresponding to seven different lines of sight through the plasma. The spectrograph uses a toroidal mirror together with a plane, aberration-corrected grating to disperse radiation in the 50–200 A(ring) region. Up to seven spectra are recorded simultaneously, at rates of 30–90 Hz, using a microchannel plate assembly optically coupled to a charge-coupled device camera. This will permit, during a single discharge, measurement of spatial emissivity profiles from various ionization states of an injected impurity, providing a better understanding of their time evolution and valuable information on cross-field ion transport.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1038-1043 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Modifications have been made to a 400 kV side-entry transmission electron microscope fitted with a low-field objective pole piece, in order to position apertures close to the back focal plane of the objective lens, as there is no direct access to the required position in the column. The modifications have facilitated developments in the imaging of magnetic domain structure in magnetic materials using the Foucault technique, for which the correct positioning of the objective aperture is crucial. All usual transmission electron microscopy facilities are retained, allowing a full range of specimen holders and imaging modes to be used along with TV recording and electron energy loss spectroscopy. Some initial results are presented from Fe/Cr and Co/Pt multilayer films, for which the Lorentz deflection angle is very small, and for which the Fresnel imaging mode is of limited use as the grain structure contrast masks the magnetic contrast. Initial results are also presented from NdFeB permanent magnet material for which the use of a high electron accelerating voltage is necessary.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1061-1065 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: High intensity synchrotron x-ray radiation has increased the feasibility of studying the solid–liquid interface in situ. Recent work on the structure of Au single crystal electrodes has shown the need to merge appropriate electrochemical cell designs to work on standard four-circle diffractometers. In this report, a new electrochemical cell is described for use in in situ structure determination. The cell provides excellent electrochemical control of the electrode surface, as determined by the cyclic voltammagram, in conjunction with the x-ray studies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1071-1075 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Self-supporting diamond sheets, made by the metastable chemical vapor deposition (CVD) technique, have been reported to have a range of properties, presumably dependent on the morphological details and the impurity burden of the particular sample. CVD diamonds are typically in the form of large area (i.e., many square cm) sheets averaging a few hundred microns in thickness. For this form of matter, a novel method of thermal conductivity measurement is reported based upon the well-known principle of the phase lag of a traveling thermal wave. In the present variation of this technique, the traveling wave traverses the diamond sheet from its leading edge (which was pulsed with an infrared diode laser) through the point of measurement. The average thermal diffusivity of the sheet was calculated. The equipment is relatively simple and the sample preparation minimal. Both theoretical and experimental details are given. The random error in thermal diffusivity measurements is estimated to be about 7% due mainly to uncertainties in estimating the delay time lag of the thermal wave as it travels along the length of the diamond sheet.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1076-1080 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We report a new microcalorimetric technique which allows simultaneous measurements of the heat capacity and the rate of enthalpy release during the chemical reaction in a substance under quasi-isothermal conditions. The basic features of the instrument are presented together with brief experimental results on the polymerization of diglycidyl ether of bisphenol A mixed with ethylene diamine. The instrumentation is an advance for studies of both synthetic and biological formation of macromolecules, for now it becomes possible to measure the heat capacity of a time-variant system and to characterize its vitrification transition occurring at constant temperature, as the growth of the macromolecule by chemical reaction increases the sample's viscosity. The abrupt decrease observed in the heat capacity curve corresponds to the vitrification transition, which cannot be observed in the corresponding enthalpy release curve. The present calorimeter has an important use in both technological assessment and in understanding the fundamental aspects of the vitrification phenomenon.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 854-857 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Time-of-flight spectra for Maxwell–Boltzman (MB) distributions of antiprotons initially held in an ion trap and detected after being launched through a 50-cm-long shielding drift tube have been calculated. The distributions used are of temperature 0.4–40 K, cubic length 0.003–3.0 cm, and number 10–100 particles. The mutual Coulomb repulsion of the particles causes a reduction in the number of late arrival particles expected from the MB velocity distribution. The Coulomb energy is not equally divided among the particles during the expansion. The energy is transferred preferentially to the outer particles so that the reduction in the number of slow particles is not necessarily large. The reduction factor is found to be greater than unity when the potential energy of the trapped ions is greater than ∼5% of the ions' kinetic energy and is ∼2 for the launch parameters of the Los Alamos antiproton gravity experiment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 864-869 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A methodology is presented in order to optically characterize large, absorbing irregularly shaped particles. Two experimental systems were developed and implemented: a particle nephelometer which measures angular scattering from a single electrodynamically levitated particle at λ=514.5 nm, and an integrating sphere spectrometer which measures the spectral hemispherical reflectance of particulates in the wavelength range from 450 to 1959 nm. The particulates examined were spherical carbon particles and different oil shale particles. Measurements of phase function and cross polarization on individual particles indicate an increase in back scatter with increasing particle albedo. Criteria for particle discrimination are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 870-875 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A far-infrared rotating-analyzer ellipsometer which uses a step-tunable, optically pumped gas laser as its light source is described herein. As polarizers novel metal grids with 10 000:1 polarization contrast were used. The instrument determines the complex dielectric function in the spectral range between 10 and 150 cm−1. A cryostat allows both reflection and transmission measurements from 10 to 330 K. Measurements of the birefringence of crystalline quartz, of both the carrier density and the scattering frequency of doped semiconductors, and of the low energy excitations of high-TC YBaCuO ceramics are presented herein.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 890-895 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An easily realized inelastic electron tunneling spectrometer (IETS) controlled by computer through an IEEE-488 interface bus is described. Components and circuits of the system are described in detail in order to help newcomers to IETS build a research quality spectrometer on a relatively low budget. The system design is much simpler and easier to implement than others reported in the literature, and experimental results indicate that the spectrometer has comparable resolution and signal-to-noise ratio. Additionally, in-house software routines offer the system considerable flexibility in spectral data manipulation, for example, background correction, numerical differentiation, and subtraction of one spectrum from another may be performed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 900-903 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An improved and reliable method for making sharp scanning tunneling microscopy (STM) tips is described. It is based on the widely used drop-off electrochemical etching procedure, here modified to improve the control of the tip shape. A second etching is applied not only to remove the oxide layer from the tip surface, but also to sharpen the STM tips further. A tip radius less than 20 nm can be obtained reproducibly. The quality of the produced tips was inspected with transmission electron microscopy, and micrographs of tips produced with different times of second etching are shown. To produce tips which are all without an oxide layer an electronic phase control unit is necessary. Even without this etch controller more than half the tips are oxide free, and then only standard laboratory equipment is used for the tip production.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 912-916 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A detection technique for use with noncontact attractive mode force microscopes is described. The technique relies on the accurate measurement of the resonant frequency of a cantilever probe as it rings in response to a very short excitation pulse. The resonant frequency reflects the spatially varying interactions between the probe and the specimen under study. This technique is for cantilevers with relatively high Q values ((approximately-greater-than)1000) as might be expected with vacuum operation. This technique has the advantage of being relatively easy to implement with commercially available instrumentation, while still providing excellent sensitivity and wide bandwidth operation. A sensitivity of 0.02 Hz at 75 kHz in a bandwidth of 50 Hz is comparable with other techniques. In addition, it is easy to accommodate a wide variety of cantilevers with different vibrational characteristics. A photomicrograph of the stray fields above bits written in a magnetic hard disk is presented, demonstrating the application of the technique to magnetic force microscopy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We present a method of lowering below 2.5 Hz the vertical normal mode frequencies of the Pisa Super Attenuator by using permanent magnets which provide an antispring force. This method allows a more efficient suppression of the seismic noise decreasing the lower limit of the frequency region devoted to gravitational wave detection.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 618-622 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An instrument, based on the principle of microscopic measurements using transient reflecting gratings, has been built for investigation of modified metallic surfaces. After holographic illumination of focused light pulses of short duration, dynamic processes are observed by detecting the reflecting diffraction of the synchronously delayed probe pulse, while the sample is two-dimensionally scanned. Distribution imaging and relaxation time (or diffusivity) imaging are demonstrated for ion-implanted silicon wafers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 802-805 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The design and implementation of a variable temperature, easily automated torque magnetometer is described which utilizes a commercial capacitive-based transducer system. Absolute calibration is accomplished with a current-carrying coil and the constant is found to be temperature independent to within ±0.5% over the cryogenic to room temperature range measured. Linearity is observed in all signal levels measured, ranging over four orders of magnitude, from 0.003 to 50 dyn cm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 821-822 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: This note presents an active electronic circuit which controls the voltage applied to a device under test of very low input impedance. Performances and applications of this circuit are given in the superconducting field.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 825-826 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have designed a simple micrometer driven coarse motion stage for scanning probe microscopy. It was tested with a tube scanner based scanning tunneling microscope (STM) of the Lægsgaard/Besenbacher type. A lateral kinematic mount is used for sample positioning. The reproducibility of sample positioning is in principle only limited by the quality of the micrometers. Our design involves exchangeable sample mounts which may be adapted to the users' requirements. The stage does not cause deterioration in the resonance behavior of the STM and preserves the capability to obtain atomic resolution on graphite.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 724-727 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: For the simulation of hypervelocity impact of micrometeoroids and microdebris on a spacecraft, an improved acceleration technique is proposed in a magnetoplasmadynamic accelerator. The compression of the plasma flow was enhanced due to modification of the magnetic-compressor-coil geometry in the accelerator. Such enhancement was found to be effective for the improvement of the flight parameters of microprojectiles. Due to the modification of the coil geometry, the velocity of glass beads of 500–600 μm diam was increased from about 3 to 6 km/s which is included in the hypervelocity impact regime of projectiles in space. In addition, the main direction of the projectile flight was improved to become more parallel to the central axis of the accelerator.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 732-736 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: For ion beams used for ion beam etching and sputtering in electronic device technology and for monitoring plasma wall interactions, a pyroelectric detector has been developed to measure the current density of neutralized ions and the fraction of the total beam which is neutralized. The pyroelectrically induced charges due to beam heating of a PVDF film and the deposited charge from the ion beam are measured with a charge sensitive and current sensitive amplifier, respectively. The pyroelectric detector has a sensitivity of 1000 V/W and 1/e response time of 2 s. Beam current densities in the range 0.01–100 μA/cm2 of 1 keV particle energy can be measured.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 756-759 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have measured the temperature coefficient of the output of several ratio transformers at ratios near 0.500 000 using an ac bridge and a dual-phase, lock-in amplifier. The two orthogonal output components were each resolved to ±1 ppb of the bridge drive signal. The results for three commercial ratio transformers (an ESI DT72A, a Gertsch RT-1665u, and an Eaton PRT-10C) between 20 and 50 °C range from 0.5 to 100 ppb/K for the signal component in phase with the bridge drive, and from 4 to 300 ppb/K for the quadrature component.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 774-780 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The article discusses the underlying hypothesis, the limits, the range of application, and the practical operation of a versatile thermal conductivity analyzer based on a transient cylindrical probe method. The best expected precision for the conductivity determination appears to be ∼±10%. A compact analyzer, integrating all the apparatus' components in the same unit, has been specifically designed for environmental research in the field. Calibration received special attention regarding thermal conductivity values in the range 0.1–3 W/mK. The analyzer was tested on seven materials, in field conditions, and discrepancies from published conductivity values did not exceed 9%. Several checks were performed in the laboratory to study the influence of experimental conditions, such as the probe insertion technique. The cylindrical probe method appears well suited to powdered materials, but may also be applied to viscous liquids and solid matter. As an application, the cylindrical probe was used to characterize nine soils from the Belgian Lorraine. After soil analysis in the dry state, thermal conductivity of each sample was determined at different moisture contents. The transient cylindrical probe method proved to be quick and easy, whether in situ or on samples in the laboratory. It is a powerful tool which can map a country's soil thermal properties.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3380-3383 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Feedback between optical elements can be a major source of noise when trying to attain high sensitivity in infrared absorption experiments. We find that a conventional White-cell optical arrangement introduces étaloning fringes that modulate the peak-to-peak amplitude of our signals by 1 part in 16 666, a fractional change of 6×10−5. Although relatively small, this "noise'' is systematic and adds coherently with averaging, obscuring interesting absorption features. An easily constructed multipass optical system suited for performing high-resolution infrared spectroscopy in molecular beams is described. The design is based on a variation of the White cell and has been optimized for use with lead salt diode lasers. One of the key components in the improved design is the addition of an oscillating mirror for spoiling optical feedback generated by laser scatter and/or poor mode coupling of the laser to the multipass optics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3413-3424 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A novel method for reconstructing the apparatus response function required for accurate detailed analysis of nanosecond time-resolved fluorescence decay data is proposed and tested with properly constructed simulated data sets for a variety of pertinent cases, using the high-accuracy convolution algorithm previously developed [J. Vecer, A. A. Kowalczyk, and R. E. Dale, Rev. Sci. Instrum. 64, xxx (1993)]. The veracity of recovery of test mono- and multiexponential decay responses by this method, involving the use of two appropriately chosen monoexponential reference decay responses, is shown to be essentially identical to that attainable with the "true'' apparatus response function. The method is also demonstrated to exhibit significant advantages in a variety of situations over currently the most widely employed method of overcoming extant problems in the direct determination of an appropriate apparatus function: indirect analysis against a monoexponential reference decay response (δ-function convolution method, F-F deconvolution).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3456-3461 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have developed a Macintosh computer program to analyze Debye–Scherrer x-ray powder diffraction films digitized with a conventional scanner. The program uses a fast derivatives-free procedure to fit distorted ellipses corresponding to the diffraction rings on the film. These ellipses are collapsed into a one-dimensional plot of intensity versus scattering angle, from which one can extract information about the diffraction pattern that would have been lost in visual reading. Moreover, uncertainties are decreased by a factor of ∼30 over visual reading, and the analysis of diffraction films is reduced to a matter of minutes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 446-451 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Computer simulation is used to optimize the design of a large-field electron image projector system. Aberrations from mask to target are smaller than 0.02 μm in distortion and 0.12 μm in beam resolution for a 27×27 mm2 field size, 3:1 reduction system, with a 4-m optical path distance. The lenses are given nonuniform bores. The bottom of mask-side lens and the top of wafer-side lens are reduced in diameter to 1/4 of the other bore diameters. The axial direction tolerance for lenses, mask, and target positions is found to be much larger than errors that are anticipated to occur during assembly. The reduction factor can be adjusted to the value designed by adjusting lens positions or mask and target positions, and can be adjusted for the wafer linear distortion through adjusting the lens current ratio of two lenses. We have identified, but not solved, two remaining problems in the lithography system. One is the large emittance electron gun and the other is a condenser lenses spherical aberration.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 492-494 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An instrument for measuring the elastic moduli at several ultrasonic frequencies, using a single quartz crystal, has been developed. In the past an array of pairs of oscillators was used as part of the piezoelectric ultrasonic composite oscillator technique to measure the dynamic Young's modulus and shear modulus at several ultrasonic frequencies. Experimentation was done using the conventional composite and the new single crystal systems at 40, 80, and 160 kHz on brass and aluminum samples, both in the longitudinal and torsional modes. The good agreement between these systems is indicative of the validity and applicability of the new design.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 346-348 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have developed an electrostatically driven tuning fork chopper which is compatible with an ultrahigh vacuum (UHV) environment. Constructed with a commercially available tuning fork using stainless steel and alumina parts, the chopper is capable of operating while exposed to high temperature samples and corrosive gases. Operation in an UHV environment while modulating both optical and molecular beams is demonstrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3524-3529 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An ultrahigh vacuum atomic force microscope (UHV–AFM) with tunneling current detection has been developed. This microscope uses a new type of pantograph inchworm system. The features of the inchworm system are (i) operation of the clamp in normal clamping mode, (ii) an enlargement of the piezo device stroke for clamper stroke, and (iii) compact system for easy use. Our UHV–AFM has (i) six inchworm movements based on the new mechanism, and (ii) a sharp AFM probe whose tip is machined by a focused ion beam fabrication technique. UHV pressure experiments demonstrate that this system provides a contamination-free surface and can observe atomic resolution AFM images of MoS2 and silicon carbide.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3534-3537 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We developed a piezoelectric scanner for probe microscopes that uses only single-domain LiNbO3 crystals as a piezoelectric transducer material in order to avoid nonlinearity, hysteresis, and creep that is always present in piezoelectric ceramics. A raster area of about 50×50 nm2 is within reach of a scanner that uses three double-plate translators and a scanning voltage of 300 V peak to peak. The performance of monocrystal scanners for investigations in the range of atomic resolution is demonstrated by imaging the well-known surface of highly oriented pyrolytic graphite.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3563-3571 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: It has been found that the photopyroelectric (PPE) sensor made of thin-film polyvinylidene fluoride, sputter coated with palladium, can detect trace hydrogen gas in the presence of pure oxygen without significant drift and stabilization problems. Presently, hydrogen concentration as low as 0.1% in flowing 99.9% oxygen has been detected under standard temperature and pressure conditions. The detector has been used without a reference sensor (single mode) which simplifies the sensor system compared to previous work, at the expense of sensitivity limits. This paper describes the detection of hydrogen gas in hydrogen/oxygen mixtures, and deals with some instrumental aspects of the PPE sensor device such as background noise and signal drift. Some techniques for stabilization are also discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3585-3593 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Enthalpy probe measurements in compressible argon/helium thermal plasma jets are compared with results from high spectral resolution laser light scattering. In the laser scattering measurement the plasma temperature and velocity are determined directly from high-resolution line-shape analysis of light scattered by the plasma. The technique yields an unambiguous determination of gas or kinetic temperature without the assumption of local thermodynamic equilibrium. Velocity is determined directly from the measured Doppler shift. The enthalpy probe is a combination stagnation probe and flowing calorimeter. Gas temperatures and velocities are calculated from measured values using both frozen flow and equilibrium flow assumptions for the stagnation process. Over the Mach number range examined, the assumption of isentropic, frozen composition stagnation best matches the laser results. In the jet periphery a significant streamline displacement is caused by the presence of the probe. The displacement, which is a function of the nondimensional radial velocity gradient, distorts the velocity and temperature results in the wings of the profiles. In the core of the jets examined, probe measurements in both subsonic and supersonic compressible flows show excellent agreement with laser scattering results.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3612-3616 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An improved ac method to measure the thermal diffusivity in an extended temperature range is presented. The basic idea is to solder thermocouple wires directly on the sample, so that the sample itself acts as a thermocouple junction and the relaxation time for the temperature measurement becomes negligible. This new technique allows one to measure smaller samples and to increase the frequency of measurement so that the thermal losses could in principle be completely neglected. Finally, by the particular geometry a concurrent measurement of the electrical resistivity is obtained.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3639-3640 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An automatic arrangement for investigation of thermal switching in transparent ferroelastic crystals is described. The polarization microscope image converted by the CCD camera is analyzed using a PC computer equipped with a real-time video image digitizer card.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3644-3646 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A scheme is described that resolves the problem of coupling sensitive equipment to a heat exchanger while retaining excellent isolation against vibrations in an ultrahigh vacuum environment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3620-3626 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The development and the test results of an electron-beam furnace for the later utilization in a microgravitational environment are reported. By just varying the deflection pattern by means of the electron-optical components two reference profiles, a gradient profile with a maximum slope of 220 K/cm, and a hot zone profile with a zone temperature of 1520 K could be established and maintained. A beam power of 550 W had to be applied to a sample made of massive Ta for the gradient profile, for creating a hot zone profile an input power of only 250 W onto a sample with a ceramic core was sufficient. A continuous pyrometric measurement system with a high local and time resolution has been realized. By temperature sensing of the sample with this system an intrinsic feature of electron-beam heating could be directly observed, the sharply localized energy deposition at the sample surface.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3647-3648 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An evaporation source of simple and compact construction was devised. This source is 20 mm in diameter and 30 mm long; is composed of a ring filament, control aperture, and disk-shaped sample (source) and shield cover; and enables the evaporation of source material to be easily controlled at a constant rate without the use of a feedback system. This evaporation source ensures depositions at constant rates for several hours. Refractory metal films of several thousand angstroms thickness can be deposited onto substrates held 10 cm from the source. Typical performance characteristics in the application to Ti films are presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3651-3652 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We briefly present the properties of a liquid/elastic solid interface wave called "Scholte–Stoneley wave.'' This wave is generated when a bulk wave meets the edge of the elastic solid in a perpendicular plane. This study leads to an original device for generating the Scholte wave. Using this simple setup, we show that the Scholte wave is diffracted by a default in the depth of the solid surface. In the same manner the commune extremity of two different solids stuck together is detected by this wave.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3072-3075 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A degenerate-four-wave-mixing apparatus is described, with novel data acquisition, and sample handling techniques. Particular attention is paid to methods of noise reduction and elimination. Four-wave mixing is performed with Nd:YAG laser light, at both 532 and 1064 nm, and with a pulse length of 20 ns.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3066-3071 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A novel gas target was developed for use in laser-atom harmonic-generation experiments. It operates on the principles of free molecular flow rather than those of fluid flow as does a gas jet. This allows much lower gas pressures to be achieved. The device is a small, cylindrical, double-ended hole through which the focused laser beam passes. Gas enters from the middle of the cylindrical wall and quickly disperses as it emerges out the hole openings. As with the gas jet, the purpose of the gas target is to provide a very narrow and localized distribution of gas for laser interaction. Some of the advantages of the target relative to the jet are that it is easier to systematically align to the laser beam and it can operate at much lower pressures. Results of a Monte Carlo simulation of the gas density and flow rate within the target and experimental measurements of the density profile made by imaging the recombination emission are presented herein. It is found that the gas density decreases rapidly once outside the target hole openings along the symmetry axis. The calculations are in good agreement with experimental measurements. The gas target continues to function without serious deviation at pressures up to ten times above the molecular flow range.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 524-528 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: High-temperature zeta potentials of oxides are important in understanding and preventing the deposition of corrosion products, particularly in nuclear power plants. They are also important in separation of minerals from coal/mineral aggregates and sol-gel processing of high-density advanced ceramics at supercritical temperatures. In this paper, a computer-interfaced experimental arrangement for the determination of high-temperature zeta potential via streaming potential measurements is described. Zeta potentials of oxides were calculated from the slopes of streaming potential versus differential pressure plots, avoiding any errors associated with the asymmetry of electrodes. The same measurement technique can be modified to determine the zeta potentials of solid conducting surfaces and coating materials. The oxides show the ability to retain a higher surface charge at high temperatures, presumably due to stronger acid/base dissociation of the surface hydroxyl groups. Consequently, the pH of zero charge of the oxides are shifted to lower values at higher temperatures as reported in the literature, indicating the importance of making these measurements at the desired temperature.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 542-547 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A method using two-wavelength pyrometry has been developed for the measurement of the cathode surface temperature of high-current free-burning arcs. The method measures the total thermal radiation flux emitted from the cathode and the surrounding plasma and subtracts the derived plasma component using a modified Abel-inversion transformation. The effects associated with the plasma radiation reflected by the cathode are minimized by using measurements near the cathode edges. Experimental data are used to account for the dependency of the cathode emissivity on wavelength. In this paper the details of this technique are discussed and measurements of cathode surface temperature are presented for pure and thoriated tungsten cathodes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 577-578 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new system illuminates liquid solutions with simulated sunlight, at constant temperature and with rapid mixing of the solution. Based on irradiance measurements, the relative spectral composition of the simulated sunlight is very similar to that of authentic sunlight at the earth's surface.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 581-582 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The emerging field of vacuum microelectronics has many promising applications including flat-panel displays, microwave devices, and ionization sources. The technology is based on arrays of microfabricated micrometer-scaled gated field emitters. Applications are currently limited by unacceptable reliability due primarily to failures of individual field emitters. The failure of an individual emitter produces a characteristic electrical pulse. A circuit is used to monitor and count these pulses. The technique provides a powerful tool for exploration of stable operating regimes for vacuum microelectronic devices and may be useful in other areas in which vacuum discharges must be monitored.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 587-588 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe a simple, inexpensive sample container for neutron scattering at nonambient temperatures. The sample cell works equally well with reactive glasses, crystalline powders, or high vapor pressure liquids. Demonstrated performance has been obtained at temperatures from 10 K to 350 °C.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3394-3402 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An apparatus and data analysis methodology is described which allows determination of response time to oxygen concentration changes of luminescent oxygen sensor coatings. Utilizing a solenoid valve, a sample chamber creates a pressure jump from 0.1 to 700 Torr in 600 μs that is followed by 15 ms of ringing. An optical detection system measures the response of porphyrin-based luminescent oxygen sensors to the pressure jump. The pressure in the chamber is measured simultaneously and independently with a piezoresistive pressure transducer. Data analysis techniques using nonlinear least-squares and numerical convolution of the luminescent response to the pressure rise allow determination of response times of the oxygen sensor. The response to pressure jumps of several luminescent oxygen sensitive coatings designed for video luminescent barometry are measured with this computer-controlled instrument. Several coatings were studied with response times of ∼2.5 s, ∼400 ms, 11 ms, 1.5 ms, and 〈25 μs. Studies of the system suggest that we can determine response times down to about 10 μs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3425-3429 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The combination of a variable wavelength interference filter and a position-sensitive photon-counting detector provide spectra of low-intensity luminescence. This method has been demonstrated on two luminescent materials, europium (II)-doped barium fluorobromide [BaFBr/Eu(II)] and uranyl nitrate [UO2(NO3)2⋅6H2O]. Pixel-by-pixel division of a luminescence image taken through the filter by an image without the filter corrects for variations in image intensity. The intensity along the long axis of the filter after correction for detector sensitivity constitutes a luminescence emission spectrum. BaFBr/Eu(II) gave delayed emission with a maximum intensity at 395 nm, in reasonable agreement with the measured Eu 5d→4f fluorescence maximum that occurs at 389 nm. The same technique applied to UO2(NO3)2⋅6H2O gave peaks at 511, 539, 567, and ∼600 nm. These did not correspond to experimental fluorescence maxima due to differing self-absorption effects.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3430-3439 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A time-resolved spectral photometer, i.e., an instrument for simultaneously measuring intensity, time, and wavelength (I-t-λ) is described. The "spectro-streak'' apparatus comprises a grating objective coupled to a commercial streak camera with 2-ps resolution, a channel plate amplifier, a CCD camera, and a computer for data processing. The necessary calibration and correction procedures are discussed in detail; these are sweep nonlinearity correction, shading correction, geometric distortion correction, wavelength calibration, spectral intensity correction, and dispersion correction. The performance of the instrument is demonstrated with an example of current interest, the measurement of the solvatochromic dynamic Stokes shift of fluorescence from a charge-transfer system in solution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3542-3547 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new high-speed digital framing camera is described. The design is built around a rotating polygon mirror that provides a framing rate of 24 000 frames/s. The camera electronics digitizes an image into a 32×104 grid of pixels, where the second dimension of the grid can be varied and is determined by the 8 bit computer-aided measurement and control digitizer sampling rate. Available digitizer memory provides for 314 frames at this horizontal resolution. The advantages over other available high-speed framing cameras are (1) low cost of the system provided the digitizers are available, (2) rapid retrieval of a recorded event, and (3) the ease with which the system can be used. Sample results from an application in high-power arc photography are given to illustrate the system's spatial and temporal resolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3467-3473 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The diffraction and optical properties of several crystal concentrator configurations which could be adopted in hard x-ray astrophysical observations are discussed and compared in terms of effective area, focusing characteristics, and overall dimensions. First, a concentrator consisting of a set of circular rings covered with asymmetric mosaic crystals in Laue geometry is considered; focusing is achieved by an appropriate choice of the geometrical parameters and the asymmetry angles. Specific effective areas larger than 600 cm2 can be obtained in the energy range 120–190 keV by using Si (422) Bragg reflections in a device with a diameter of 2.5 m and a focal length of 13.5 m. Afterwards, a spherical-zone crystal concentrator is analyzed where asymmetric Laue geometry leads to focusing. With a focal length of 8 m and Si (422) reflections, the mean effective area in the energy range 100–300 keV is about 6500 times larger than the focal spot while the separation power of the concentrator is of the order of 10 arcsec. Finally, a concentrator consisting of several coaxial focusing paraboloids is analyzed. The surfaces of the paraboloids are covered by mosaic crystal tiles with lattice planes disposed normally to the meridians. By using Ge crystals with a mosaic width of ≈350 μrad and assuming a focal length f=10 m with a total aperture 2α=16 deg, it is possible to obtain effective areas larger than 1000 cm2 for energies smaller than about 150 keV. On the other hand, the ratio between the mean effective area and the size of the focal spot in the energy range 200–500 keV is higher than 10 000.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3482-3486 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A technique for quantitative analysis of gas mixtures in a laser mass spectrometer is presented. It is based on the addition of two calibration gases with different orders of multiphoton ionization process to the sample gas. The ratio of the signals of these two internal standards serves as a sensor for the laser intensity within the ionization volume. Thus strongly fluctuating signals due to higher-order multiphoton ionization can be normalized for every single laser shot. In addition, for such a relative measurement, effects of long-term drifts of the apparatus are eliminated. Concentrations varying from a few ppm to several percent could be determined with an accuracy better than 10% at every single laser shot. Therefore this technique allows high time resolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3627-3633 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A novel scheme for robust feedback control of a charged particle in an electrodynamic chamber has been designed and applied. The determination of the particle position is based on photodiode array (PDA) shadowgraphy. A 128 linear PDA is used to measure the trace of the particle. The PDA trace is transferred to a PC computer by a special purpose digitizer. Analog-to-digital conversion is realized by feeding the signal through a hard limiter and measuring the time that corresponds to the shadow and light zones. The designed hardware allows a high sampling rate (7.8 kHz). The obtained position value is used by a PID algorithm to control the particle position. The one-to-one correspondence between the calculated and experimental trajectories allows one to study the system performance by simulation rather than by experiments and to assign the proper controller to the specific application. It is shown that the system is insensitive to extreme variations in particle size.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3641-3643 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The electrical prebreakdown currents in liquid and solid dielectrics under a highly nonuniform electric field condition have been measured successfully using an electro-optical current measuring system in conjunction with a 760-ns rectangular high-voltage pulse generator. The breakdown time lag was precisely measured from the current. The discharge propagation velocity was estimated from the linear relation to formative time lag and gap spacing to be 18 km/s in liquid nitrogen at +40-kV point voltage.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3649-3650 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A technique based on the Stark effect is described that allows the residual electric field in a small experimental volume to be systematically reduced to (approximately-less-than)50 μV cm−1. Although developed initially to allow production of Rydberg atoms in states with very large values of principal quantum number n, it will also permit high resolution studies involving near threshold photoionization or very low-energy free electrons.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3061-3065 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An average laser output power as high as 5 kW has been produced from a transversely excited atmospheric CO2 laser pumped with a new solid state exciter. The exciter providing a 100 J transfer energy consisted of a high voltage pulse generator and a two stage magnetic pulse compressor. A stack of new high power semiconductor switches, called insulated gate bipolar transistors, was employed for the main switch of the pulse generator. A sophisticated discharge head with the corona preionization behind a perforated anode was designed to realize fast and uniform gas flow in cooperation with acoustic dampers. The maximum average laser power of 4.6 kW was attained at a repetition rate of 550 pps with an overall efficiency as high as 10.5%. The maximum repetition rate achieved was 1.1 kpps, at which the resulting average laser power was 3.4 kW.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3053-3060 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Current sources in the human body can be localized by measuring the biomagnetic fields with multichannel SQUID systems. Important system aspects are the noise level, the ambient field suppression, the dynamic range, the reliability, the number of channels, and the arrangement of gradiometers. From the user's point of view the most important quality factor is the accuracy with which a current dipole can be localized. A test procedure is proposed to determine the localization power of the system. A 31-channel-SQUID system is presented together with the results of the test. The crucial parts of the system determining the accuracy are pointed out.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3094-3103 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe a design for a paraboloidal electrostatic reflector (PER) adapted for molecular-beam time-of-flight (TOF) photoelectron spectrometers. The PER offers a nearly two orders of magnitude improvement in detection efficiency over standard line-of-sight TOF detection. The energy resolution ΔE/E is nominally about 0.02, but can be improved to about 0.005 (to a current limit of ΔE=10 meV) at some expense in sensitivity. The PER makes possible sensitive measurements for inherently weak ionization experiments. We have used our spectrometer in applications involving low-power picosecond pulses, low-density molecular clusters, and ionization through dissociative states.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3082-3087 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An optical interferometric approach is described for the measurement of axial eye length. The technique uses the short coherence length characteristics of the light source to locate, interferometrically, the position of the front surface of the eye and the retina. Results are presented from studies on an idealized model eye and the precision of the measurement is discussed. The advantages of the technique and a comparison with previously used short coherence measurements are also reviewed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3108-3110 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A cryogenic photoacoustic cell has been developed for intracavity use in a tunable ring laser. Its design ensures uniform cooling of the gas sample and minimum loss to the laser cavity. Also implemented is a flexible microphone mounting system that reduces thermal stress during temperature changes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have embodied a new version of two-dimensional display-type spherical mirror analyzer [H. Daimon and S. Ino, Rev. Sci. Instrum. 61, 57(1990)]. A couple of concentric hemispherical small grids and 12 pairs of obstacle rings have been attached to the original type of analyzer in order to operate with a constant pass-energy mode and improve the uniformity of the energy resolution of the analyzer all over the detection area, respectively. We performed a test on the resolution of the analyzer, and applied it to the simultaneous angle-resolved photoelectron spectroscopy on the band structures of single-crystal graphite (Kish graphite) within the acceptance cone of ±50°. The observed band structure is in good agreement with those reported by other investigators. We observed a ring-like pattern which enlarged as the binding energy approached the Fermi level. This ring is ascribed to the cross section of the π band. Although the designed energy resolution is 1% of the pass energy, the minimum value realized reached in this study was 0.2 eV for the pass energy of 10 eV [H. Daimon, Rev. Sci. Instrum. 59, 545 (1988); 61, 205 (1990)].
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2898-2900 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new detection scheme of resonance and antiresonance frequencies of piezoelectric resonators by utilizing an inductive pulse detection method is developed. This method is applied to a disk piezoelectric resonator and advantages over the conventional ones are noticed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2892-2897 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A stand-alone atomic force microscope (AFM) featuring large scan, friction measurement, atomic resolution, and liquid operation, has been developed. Cantilever displacements are measured using the optical beam deflection method. The laser diode and focusing lens are positioned inside the piezo tube and the cantilever at the end of the piezo tube. Because the laser beam stays on the cantilever during scanning, the scan range is solely determined by the characteristics of the piezo tube. In our case 30×30×9.5 μm3 (xyz). The optical beam deflection detection method allows simultaneous measurement of height displacements and torsion (induced by lateral forces) of the cantilever. AFM images of dried lymphocytes reveal features in the torsion images, which are only faintly visible in the normal height images. A new way of detecting the nonlinear behavior of the piezo tube is described. With this information the piezo scan is linearized. The nonlinearity in a 30-μm scan is reduced from 40% to about 1%, as is illustrated with images of a compact disk. The stand-alone AFM can be combined with a (confocal) inverted microscope, yielding a versatile setup for biological applications.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2901-2904 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A computer model for correcting the spatial distortion in images acquired with a high-speed image converter camera is described. The distortion is caused by electrodynamic interaction of the photoelectric currents within the image converter camera, and appears as an inward bowing of the individual high-speed images. The model is implemented in a postprocessing algorithm, using the pixel values in an image to infer the interacting photoelectric currents and thus allow computation of the distorting force acting on each pixel. The force is converted into a corrective translation using three system parameters which are determined by analyzing images for which the predistortion geometry is known. Measurements on a variety of test images show the model removes up to 85% of the image converter distortion.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2920-2925 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have built a low temperature scanning force microscope which is able to measure contact and noncontact forces using the dc modes of force microscopy. We demonstrate the capabilities of our instrument on a magneto-optical disk at room temperature and at 77 K. Using a ferromagnetic thin film tip, the topography and the micromagnetic stray field of the sample is measured using the dc modes of force microscopy. The topographic and magnetic data are precisely correlated. The circular bit structure and the natural domain structure between the homogeneously magnetized bits is clearly visible. A lateral resolution below 100 nm and a force resolution of 10−12 N is reproducibly achieved.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2930-2932 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A device meant as a supplement to a standard electron paramagnetic resonance spectrometer, permitting easy and accurate determination of the Tc-onset critical temperature superconductors, has been designed and constructed. The method of tracing microwave absorption changes permits detecting even very small amounts of the superconducting phase and determining the Tc-onset critical temperature with an accuracy of an order of 0.1 K.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2938-2941 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We report on a sensitive and reliable ac technique to measure the Seebeck coefficient S of materials, in particular of high Tc superconductors. The small temperature difference between the ends of the sample allows structure in the S(T) curve to be observed. This technique avoids the creation of a component proportional to dS/dT in the measured signal. Such a component has in the past led to erroneous conclusions regarding the high-temperature superconductor YBCO. A mathematical analysis shows the origin of this component and how it can be avoided. These predictions are confirmed by experiments on a YBCO single crystal.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2952-2953 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We present an apparatus for controlling the deposition of thin films. The apparatus is based on a quartz resonator whose frequency is controlled digitally by a computer. Temperature variations of the quartz during the evaporation process, attributed to the exothermic heat of condensation and radiation heating from the evaporation source, are compensated. A very stable deposition rate and a good film thickness evaluation are obtained.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2954-2960 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An experimental technique to measure simultaneously the thermal diffusivity and thermal conductivity of small specimens of thermal-insulator materials is described. Experimental conditions are developed which approach the mathematical idealization of a one-dimensional, infinite, two-component, composite solid whose planar interface is subjected to a step-function heat flux. The heat flux is generated by resistive heating of a thin metallic foil. Although this principle has been exploited previously, the present technique permits specimens with volumes two orders of magnitude smaller than prior work based on the same idealization. A number of difficulties related to small specimen volume are identified and overcome. Another improvement over past efforts is the use of the nonlinear least-squares analysis to determine the optimum values for diffusivity and conductivity. A comparison of measurements of these properties for acrylic and Pyrex glass with literature values suggests that the technique affords accuracies of about 5% for materials in this range.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2961-2970 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: This article discusses recent developments in high-temperature electrostatic levitation technology for containerless processing of metals and alloys. Presented is the first demonstration of an electrostatic levitation technology which can levitate metals and alloys (2–4 mm diam spheres) in vacuum and of superheating-undercooling-recalescence cycles which can be repeated while maintaining good positioning stability. The electrostatic levitator (ESL) has several important advantages over the electromagnetic levitator. Most important is the wide range of sample temperature which can be achieved without affecting levitation. This article also describes the general architecture of the levitator, electrode design, position control hardware and software, sample heating, charging, and preparation methods, and operational procedures. Particular emphasis is given to sample charging by photoelectric and thermionic emission. While this ESL is more oriented toward ground-based operation, an extension to microgravity applications is also addressed briefly. The system performance was demonstrated by showing multiple superheating-undercooling-recalescence cycles in a zirconium sample (Tm=2128 K). This levitator, when fully matured, will be a valuable tool both in Earth-based and space-based laboratories for the study of thermophysical properties of undercooled liquids, nucleation kinetics, the creation of metastable phases, and access to a wide range of materials with novel properties.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3006-3008 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We demonstrate a large current power crowbar switch using thyristors without complex snubber circuits. Current sharing was obtained by selecting circuit elements for uniform impedance of parallel switches and varistors were used for voltage sharing between series elements.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2999-3005 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The method of measuring temperatures in rotating systems developed by Borchard and Hermanns is applied to the routine use in analytical ultracentrifugation. The temperature measuring device is built into a so-called counterbalance cell which is used for distance calibration as well as for a correct mass balance of the rotor. Now it is possible to measure temperatures with high precision of better than 0.1 °C in high-speed rotating systems at a defined place which is the location of the measuring cell in an analytical rotor. In the main part a temperature measuring cell consists of a differential refractometer system having refractive indices with different temperature dependences, therefore a light beam passing straight through the cell is refracted proportional to a temperature difference relative to a known temperature where the system is isorefractive. The displacement of the light beam can be measured by means of an optical system which is able to detect the refraction of a light beam. The described device can be generally used for temperature and refractive index measurements in a large field of applications. Two simple detection systems suitable for general applications are suggested. In case of a Schlieren or Rayleigh interference optical system the multifunctional cell can be used as a calibration cell if the temperature is measured with an independent detection system.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3022-3023 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Two-step electrochemical etching is used to fabricate a palladium microprobe having a tip diameter less than 20 nm. The first etching is done at 4–7 V in a solution containing 4:6 volume ratio of HCl:HNO3, while in the second the etching, low voltage pulses are used.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3030-3031 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: With a spring-loaded platform mounted on a precision minidrilling machine, it is possible to rapidly and inexpensively drill sharp sample holes down to about 100 μm in hardened metal gaskets for diamond anvil cell experiments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3034-3035 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A miniature remote alignment and control system based on systems that are used in radio-controlled models is described. The modified servos provide high output torque and proportional speed control for positioning alignment adjustments, spectrometer controls, accessories, or specimen stages.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A high-pressure proton nuclear magnetic resonance (NMR) probe for a stopped-flow method has been developed, which enables us to follow fast reactions at various pressures up to 200 MPa. The high-pressure stopped-flow NMR (HP-SF-NMR) method has been applied to the study of several reactions at high pressures: the reaction of tetramethyltin with iodine in chloroform and the solvent exchange reaction on aluminum(III) ion in N, N-dimethylformamide. The volumes of activation for the iodomerization of tin and the solvent exchange reaction on aluminum(III) were determined to be −24.9±3.8 cm3 mol−1 and −2.2±0.8 cm3 mol−1, respectively. The apparatus permits measurement of activation volumes for reactions with half lives longer than a few seconds if the nuclear relaxation time of the measured proton is short enough. Several requirements for the applicability of HP-SF-NMR are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2801-2807 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe a sensitive polarimeter for measuring optical rotation induced by chiral molecules in solution that operates in the reflectance mode. A polarized light beam is made to pass through a liquid sample two or more times before detection by reflecting the beam from the surface of the sample container. The optical activity of the sample is measured using a differential polarization detector. Our results show that, for certain initial polarization states and angular orientations of the beam with respect to the glass interfaces, high sensitivity to changes in the concentration of the sample can be achieved. Results of a theoretical analysis of the technique were confirmed by experiments in which optical rotation of glucose in water was measured using a simple apparatus that employs a light-emitting diode source. Glucose sensing in vivo and on-line monitoring of industrial processes using integrated optoelectronic sensors are discussed as potential applications.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2821-2827 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A Raman system is described which is suitable for rapid determination of Raman spectra of silicates and other weak Raman scatterers under simultaneous high-pressure and high- temperature conditions. Samples are pressurized with an argon pressure medium and Sm:YAG pressure standard in an Inconel 718 or rhenium Merrill–Bassett diamond–anvil cell that is externally heated in a vacuum oven equipped with quartz windows on either side. Raman spectra are excited and collected through the front window using ≈160° scattering geometry. A triple spectrometer in conjunction with a holographic notch filter, disperses the Raman scattered radiation onto a liquid-nitrogen-cooled CCD detector. Simultaneously measured Sm:YAG fluorescence spectra are collected through the rear window and routed via an optical fiber to a second multichannel spectrometer system equipped with a diode-array detector. The high sensitivity of the detectors and the simultaneous measurement technique enable detection of and compensation of pressure drifts occurring at high temperature. The performance of the system is demonstrated by measurement of the positions and linewidths of the high-frequency Raman modes of polycrystalline forsterite (α-Mg2SiO4) at temperatures up to 930 K at pressures of ∼8 GPa and up to 842 K at pressures in the range 12–14 GPa.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2834-2837 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: For a quasimonochromatic light source with a known spectrum, the polarization Michelson interferometer (POLMINT) can be used as a global polarization state generator that produces totally or partially polarized light at its output in states of known degree of polarization that correspond to points on and within the Poincaré sphere. Conversely, the spectral and coherence properties of a quasimonochromatic source can be determined from the Stokes parameters of light at the output of the POLMINT measured by a complete polarization state detector as functions of a mirror displacement. Applications of the POLMINT as an ellipsometer are also discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2863-2871 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A low-energy diffuse scattering electron spin detector for spin-resolved x-ray photoelectron spectroscopy (SRXPS) is described. The detector is coupled to a commercial 152-mm mean radius, 150° spherical sector electrostatic electron energy analyzer. Electron optics are described for both the transport of photoelectrons from the energy analyzer exit slit to the gold scattering target, and from the gold target to the spin analyzer electron detectors. The spin detector has an effective Sherman function of 0.078±0.008, with a figure of merit of approximately 4×10−5. The electron optical phase space acceptance EAΩ of the detector is 623 eV mm2 sr. The SRXPS apparatus performance is demonstrated with SRXPS spectra from ferromagnetic Fe and a cobalt-based ferromagnetic glass.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2872-2878 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Methods were developed to characterize tapered capillaries as x-ray concentrators capable of forming spots of intense x-ray radiation with micrometer diameters. These tapered capillaries, with somewhat controlled tapers, were produced using a gravity-based capillary puller. A device was constructed to microscopically inspect these capillaries along two orthogonal axes in order to accurately measure the tapering and bending. Both monochromatic and white hard x rays were concentrated with a variety of tapered capillaries, and the subsequent gains in intensity (flux/area) ranging from 14 to 35 are reported. Using these unique x-ray concentrators, a simple high-powered x-ray fluorescence microscope was constructed and tested. We also found that hard x-ray beams could be successfully steered by bending the capillary tip with radii as small as 5 m. In addition, preliminary ray-tracing results obtained from a two-dimensional ray-tracing program are described.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2883-2887 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The design of a sectional piezoactuator is described, and the principle of operation of a tunnel junction digital stabilization system is given. The total settling time of the system while the least significant section is in operation is 1 μs at 0.01-nm resolution (in the Z direction). The application of the sectional piezoactuator permitted an increase in operating frequency and also eliminated errors caused by the piezoceramics hysteresis. Introduction of a fast-acting ALU as a digital accumulator of regulation errors made it possible to achieve high stability of the loop operation at high operating frequencies. The system suggested can adapt the speed of the loop operation depending on the relief steepness values. The blunting of the tip and sample destruction is avoided because there is a mechanism of smooth approach of the tip to the nominal scanning height.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...