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
Filter
  • Articles  (35)
  • American Institute of Physics (AIP)  (29)
  • National Academy of Sciences  (6)
  • 1995-1999  (33)
  • 1970-1974  (2)
Collection
  • Articles  (35)
Source
Publisher
Years
Year
Journal
Topic
  • 1
    Electronic Resource
    Electronic Resource
    Two-dimensional mapping of the plasma density in the upper atmosphere with computerized ionospheric tomography (CIT) : The 39th annual meeting of division of plasma physics of APS (1998)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 5 (1998), S. 2010-2021 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Tomographic imaging of the ionosphere is a recently developed technique that uses integrated measurements and computer reconstructions to determine electron densities. The integral of electron density along vertical or oblique paths is obtained with radio transmissions from low-earth-orbiting (LEO) satellite transmitters to a chain of receivers on the earth's surface. Similar measurements along horizontal paths can be made using transmissions from Global Position System (GPS) navigation satellites to GPS receivers on LEO spacecraft. Also, the intensities of extreme ultraviolet (EUV) emissions can be measured with orbiting spectrometers. These intensities are directly related to the integral of the oxygen ion and electron densities along the instrument line of sight. Two-dimensional maps of the ionospheric plasma are produced by analyzing the combined radio and EUV data using computerized ionospheric tomography (CIT). Difficulties associated with CIT arise from the nonuniqueness of the reconstructions, owing to limited angle measurements or nonoptimal receiver location. Improvements in both reconstruction algorithms and CIT measurement systems are being implemented to overcome these difficulties. New imaging systems being developed employ CIT for large area mapping of the plasma densities in the ionosphere. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.872872
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    On the recovery of a spark gap in a fast discharge circuit (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 4242-4244 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have shown theoretically that the maximum repetition rate attainable with a switch for both resistive and resonant charging is independent of the value of energy transferred through the switch in case of a very fast discharge. Experimental confirmation of this has been achieved with a resistively charged 20 kV pulse generator (C was varied from ≅5 to 35 nF) switched by a spark gap into a load whose resistance varied from few ohms to a kΩ. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149243
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Stress determination of micromembranes using laser vibrometry (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 1965-1969 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A laser vibrometry based dynamic technique for biaxial residual stress determination in micromembranes is reported. Layered, low pressure chemical vapor deposition grown, rectangular shaped micromembranes are ultrasonically excited. The resulting micromembrane displacement, as a function of frequency and position, is recorded to yield resonance frequencies and associated vibrational mode numbers. The stress is determined from this information. Vibrations forced from ultrasonic pressure (∼25 Pa) resulted in peak displacements of tens of nanometers at resonance. For the sample set studied, the (3,1) mode resonance peak displayed the least damping in atmospheric testing and was used to establish stress levels ∼108 N/m2. A trend for this stress showing an overall decrease by ∼40% as a result of thermomechanical cycling was identified. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146952
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Latch proof operation of a switch of a high repetition rate laser with dc resonant charging (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 4813-4816 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We report on the operation of a high voltage high current switch in which command resonant charging capability is built in. Elimination of switch latch up problems do not require any extraneous and complex circuitry. The indigenously developed switch delivers power in excess of 3 kW into a dummy load typical of a TE laser at a pulse repetition rate of 200 Hz. The test on a real TEA CO2 laser load was, however, limited up to 50 Hz repetition rate beyond which the accumulation of dissociation products within the active volume led to arcing. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146157
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Anomalous capacitance–voltage profiles in quantum wells explained by a quantum mechanical model (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 2030-2032 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have developed a quantum mechanical model for understanding and explaining the capacitance–voltage (C–V) carrier profiles observed in quantum wells (QW). The external field imposed on the QW during C–V profiling changes the carrier distribution of the system. This model considers the effects of field and quantum confinement of the carriers in the well. The results obtained by iterative solutions of Schrodinger's and Poisson's equations give a better understanding of the experiments than the previous models where quantum confinement is ignored. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.364061
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Photonic band gaps with layer-by-layer double-etched structures (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 6749-6753 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Periodic layer-by-layer dielectric structures with full three-dimensional photonic band gaps have been designed and fabricated. In contrast to previous layer-by-layer structures the rods in each successive layer are at an angle of 70.5° to each other, achieved by etching both sides of a silicon wafer. Photonic band-structure calculations are utilized to optimize the photonic band gap by varying the structural geometry. The structure has been fabricated by double etching Si wafers producing millimeter wave photonic band gaps between 300 and 500 GHz, in excellent agreement with band calculations. Overetching this structure produces a multiply connected geometry and increases both the size and frequency of the photonic band gap, in very good agreement with experimental measurements. This new robust double-etched structure doubles the frequency possible from a single Si wafer, and can be scaled to produced band gaps at higher frequencies. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363802
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Ultrasound induced lubricity in microscopic contact (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 1177-1179 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A physical effect of ultrasound induced lubricity is reported. We studied the dynamic friction dependence on out-of-plane ultrasonic vibration of a sample using friction force microscopy and a scanning probe technique, the ultrasonic force microscope, which can probe the dynamics of the tip–sample elastic contact at a submicrosecond scale. The results show that friction vanishes when the tip–surface contact breaks for part of the out-of-plane vibration cycle. Moreover, the friction force reduces well before such a break, and this reduction does not depend on the normal load. This suggests the presence on the surface of a layer with viscoelastic behavior. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.120417
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Conduction-band tailing in parabolic band semiconductors (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 3328-3333 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Kane's [Phys. Rev. 131, 79 (1963)] model for the density of states for energies in the band gap is in qualitative agreement with experiment. Halperin and Lax [Phys. Rev. 148, 722 (1966)] have also suggested a model for band tailing, which is applicable to the deep tailing states. In the present study, theoretical models have been proposed for the band tailing in the case of heavily doped semiconductors that are more general than those of Kane and others. In addition, the present study also offers an E-k¯ dispersion relation for band tails in the parabolic band based on Kane's semiclassical theory. This study has helped us to obtain a different model for the density of states in the band-tailing conditions and the model is expected to agree better with experiment. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.365642
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Effect of oxygen content on the structural, transport, and magnetic properties of La1−δMn1−δO3 thin films (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 6327-6330 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: (110) oriented La1−δMn1−δO3 thin films with different oxygen content were grown on (001) LaAlO3 substrates by pulsed laser deposition. Samples prepared in higher oxygen partial pressures show a ferromagnetic transition around 200 K. The transport is thermally activated with a change in slope at the ferromagnetic transition. Samples prepared and annealed in vacuum show signatures of mixed ferromagnetic and antiferromagnetic phases, and are insulators. The pure antiferromagnetic phase (as expected and observed in bulk materials with optimum oxygen stoichiometry) was not obtained in our experiments, even in the strongly reduced films. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371693
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Shapes of generalized random walks (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 3360-3365 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Shape parameters for self-avoiding, random, and collapsed walks have been determined analytically and numerically using the results of recent work on the path integral description of generalized Brownian motion. The analytical calculations are both simple and exact, and the predicted values of the shape parameters in two and three dimensions are in close agreement with the simulation results and with the available literature data, which are generally obtained by approximate, non-trivial perturbation approaches. Typical realizations of actual walks in two dimensions suggest that despite its nonstationary character, the underlying generalized random walk process can serve as a useful minimal model of chain configurations. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.471039
    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...