ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Observation of the ν3 fundamental bands of HOSi+ and DOSi+ (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 5313-5315 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The ν3 (O–Si stretch) fundamental bands of the HOSi+ and DOSi+ molecular ions in the 9 μm region have been detected for the first time, using a tunable infrared diode laser spectrometer and a hollow cathode discharge cell. Analysis of the results yielded accurate values for the molecular rotational and centrifugal distortion parameters, as well as for the band origins, which are 1127.009 cm−1 for HOSi+ and 1103.112 cm−1 for DOSi+ . The ground vibrational state parameters are in excellent agreement with those determined from the ν1 bands of the two isotopes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457633
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The observation of the ν1 fundamental bands of HOSi+ and DOSi+ (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 5310-5312 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The ν1 (H–O) stretches of HOSi+ and DOSi+ have been observed with the difference frequency laser system in the hollow cathode discharge. The ions were observed either by discharge of (CH3)3SiOH or (CH3)3SiOD in a buffer containing H2 (or D2) and He, or by discharging SiH4 and N2O in a buffer of H2 or H2 and He. Discharging SiH4 and H2O in buffers of H2 and H2 and He was not successful in producing HOSi+. The constants obtained were: ν0=3662.364 67(15) cm−1, B000=18 260.75(22) MHz, D000=20.44(31) kHz, B100=18 195.05(23) MHz, and D100=19.91(34) kHz for HOSi+. For DOSi+ we obtained: ν0=2716.558 13 (12) cm−1, B000=16 231.05(24) MHz, D000=15.69(38) kHz, B100=16 154.41(22) MHz, and D100=15.60(33) kHz. These values agree well with the theory. The combination of the two B0 values results in r0(H–O)=0.940 A(ring) and r0(O–Si) =1.537 A(ring). The differences between these values and the calculated equilibrium values are similar to the corresponding results for HOC+.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457578
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Ultrasonic measurement of the surface area of porous materials (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 4372-4376 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have developed a technique to measure the amount of gas adsorbed on a porous solid using ultrasonic velocity measurements. This allows us to determine both the specific surface area and the porosity of the material. The technique has several advantages over conventional methods of determining absorption isotherms. No calibrated volumes or delicate balances are needed; the only measurements being of gas pressure and sound velocity. There is no need to know the mass of the sample or the dead volume of its container. Continuous and automatic measurements are possible, both during adsorption and desorption. We have demonstrated the usefulness and accuracy of this technique for two samples with very different surface areas (about 100 and 3 m2/g). In both cases, the results agree well with conventional volumetric measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.340179
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    On the temperature dependence of the magnetoresistance of ferromagnetic alloys (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 5459-5461 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The ferromagnetic anisotropy of resistivity Δρ/ρ0=(ρ(parallel)−ρ⊥)/ρ0 depends strongly on the nature of the dominant electron scattering centers, and is usually larger for impurity scattering than for phonon scattering. This explains why Δρ/ρ0 decreases with increasing temperature T in crystalline transition-metal alloys. Parker has proposed an expression for Δρ/ρ0 as a function of T, based on Matthiessen's rule. It contains the parameters (Δρ/ρ0)im and (Δρ/ρ0)ph, representing the Δρ/ρ0 values for impurity scattering and phonon scattering, respectively. In an alloy series with weak electron scattering, such as Fe-Co, (Δρ/ρ0)ph is found experimentally to be positive and equal to a fixed fraction (approximately-equal-to) (1)/(4) of (Δρ/ρ0)im. On the other hand, in crystalline alloy series with strong, resonant electron scattering, such as Ni-Fe, Fe-Cr, Fe-V, (Δρ/ρ0)ph is found to be negative and has a minimum at the composition where (Δρ/ρ0)im is maximum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.342347
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Substituting low-energy (〈30 eV) ion bombardment for elevated temperature in silicon epitaxy (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 6754-6760 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Normally required high substrate temperature for achieving epitaxial film growth can be replaced by low-energy (〈30 eV), high-current-density (∼1 mA/cm2) ion bombardment during film deposition. For this a Si substrate wafer was immersed like a large negative Langmuir probe in a low-pressure (5×10−4 Torr) mercury vapor plasma while receiving Si atoms sputtered from a Si wafer target. The Hg plasma was created by extracting a 4-A discharge current at 25-V discharge voltage from a Hg cathode spot on a liquid-Hg pool. Electron channeling patterns proved that uniform Si spitaxial films can be obtained over the whole substrate wafer area at temperatures not exceeding 300 °C. The best epitaxial films were obtained when the substrate is bombarded (by biasing) during deposition with 23-eV Hg ions. The electrical properties of the coatings indicated that the films were close, but not yet of device quality because of the impurities inherent in our non-ultrahigh-vacuum nonbakable Pyrex chamber pumped only with a 12-l/s Hg diffusion pump.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.342008
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Interfacing the IBM PC compatible for simultaneous photon-counting and wavelength scanning (1989)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 60 (1989), S. 2804-2806 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The simultaneous photon-counting and wavelength scanning by IBM compatible computers is described. Real-time photon counting is accomplished using the EG&G Ortec ACE-MCS interface board while the monochromator scan is simultaneously driven by a DCC5 multifunction counter-timer interface board. Count rates of up to 100 MHz are achieved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140665
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Versatile power supply circuit for xenon flashlamps (1989)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 60 (1989), S. 90-95 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A simple, versatile power supply designed to control xenon flashlamps is described. The circuit is configured to utilize an N-channel enhanced metal-oxide-semiconductor field effect transistor (MOSFET), taking the place of commonly used triggering devices such as a silicon controlled rectifier (SCR), or triac. Incorporation of the MOSFET permits flexible control of flash duty cycle and frequency by applying one signal to the transistor's gate. The circuit's versatility is demonstrated using an 8.3-W xenon flashlamp as an excitation source for a photodiode array based HPLC fluorescence detector. A detailed description of the power supply circuit is given, along with information on interfacing the circuit and the photodiode array.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140584
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Optical output stabilization method for direct current arc lamps (1985)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 56 (1985), S. 297-302 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A simple, effective technique for stabilizing the optical output of direct current (dc) arc lamps is described. The large output fluctuation due to arc wander in a commercially available lamp and power supply is minimized by the introduction of an alternating current (ac) waveform superimposed on the dc source voltage in conjunction with detector averaging. Arc stability is monitored indirectly by the detection of arc excited fluorescence from a standard sample. The monitored lamp output is typically maintained to within 1% relative standard deviation (RSD) by this method. Data are presented supporting the theory that arc wander is significantly reduced by the addition of an ac component to the dc lamp power. Various methods of ac introduction are discussed along with the design of a controllable oscillator circuit. The effects of variations in ac voltage and frequency on optical output stability are examined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1138347
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    A simple alkali metal ion gun (1989)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 60 (1989), S. 2653-2656 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An easily constructed alkali-metal-ion gun with a large metal-zeolite reservoir is described. The gun provides ion-beam currents from 100 eV to 5 keV in excess of 10 μA with a wide range of focal lengths. The ion trajectories of the extraction, acceleration, and focusing have been computed using the program simion. A versatile three-electrode extraction geometry that provides ion trajectories which emulate the planar diode is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140689
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Enhanced dc arc lamp performance for spectroscopic applications (1989)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 60 (1989), S. 3640-3642 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The performance of a high-pressure xenon arc lamp is enhanced by application of a combination of two techniques which (1) reduces noise due to arc wander and (2) increases the lamp intensity. Fluctuations in lamp intensity due to arc wander are minimized by the superimposition of an alternating current (ac) on the direct-current (dc) source voltage in conjunction with detector averaging. Lamp intensity is increased by the application of a static magnetic field to the arc plasma. Arc stability and intensity are monitored indirectly by measuring arc-excited Rhodamine B fluorescence. Data illustrating the effects of each technique individually and in combination are presented. Lamp output is typically maintained to less than 1% relative standard deviation while intensity is increased by as much as 127%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140468
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...