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  • 1
    Digitale Medien
    Digitale Medien
    Electronic bonding of buried interfaces determined by soft x-ray emission spectroscopy (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 3676-3681 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A nondestructive technique to study the partial density of states of atoms at buried interfaces is presented. A high density of interface atoms has been mimicked by using a periodic multilayer structure. The silicon-carbon interface was used as a test case. Fifty alternating silicon-carbon layers were laid down, in which silicon layers nominally between 3 and 30 A(ring) in thickness alternate with carbon layer pairs approximately 30 A(ring) thick made by magnetron sputtering. The silicon L2,3 emission spectra was excited by monochromatized synchrotron radiation, and the s-like partial density of states of the silicon valence band was obtained. The spectrum of the thinnest silicon layer is similar to that of silicon as an impurity. When there are approximately two layers of silicon, the spectrum resembles that of silicon carbide, and as the layers become thicker, the spectrum is similar to that of amorphous silicon.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.344079
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  • 2
    Digitale Medien
    Digitale Medien
    High-efficiency soft x-ray emission spectrometer for use with synchrotron radiation excitation (1986)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 57 (1986), S. 2680-2690 
    Details
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A new soft x-ray spectrometer designed for use with photon excitation from synchrotron light sources is described and characterized. Special design features, including a close-spaced input slit, large toroidal gratings, and a two-dimensional charge-coupled-device array based detector system, provide exceptional measuring efficiency in a 5-m Rowland circle design. Descriptions are given of the spectrometer's mechanical and detector design, and of calibration and alignment procedures. The beam line providing photon excitation from a synchrotron light source is described. Typical electron beam and/or photon excited emission spectra of Al, Si, and LiF are presented and compared with those produced by other instruments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1139078
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  • 3
    Digitale Medien
    Digitale Medien
    Quantum-confined subband transitions of a GaAs sawtooth doping superlattice (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1133-1135 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: In this letter we present for the first time the observation of quantum-confined transitions of a short-period sawtooth doping superlattice in photocurrent and luminescence. The luminescence was investigated with different laser intensities. Due to the nature of the band modulation of sawtooth doping superlattices, the resonant energies for optical transitions are dependent on the intensity of the laser beam. We present a model, which incorporates both the Kronig–Penney energy dispersion and the self-consistent intensity-dependent internal field to explain the observed energy shift. Furthermore, the differences between photocurrent and luminescence measurements are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.100739
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  • 4
    Digitale Medien
    Digitale Medien
    Photocurrent spectroscopy in a sawtooth doping superlattice (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 1967-1969 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We report an investigation of photocurrent response in a sawtooth doping superlattice which is composed of alternating n(Si) and p(Be) δ-doping layers with undoped GaAs layers (7–15 nm) between them. A selective contact method is used to measure the interesting behavior of the subband gap compared with the gap of the host semiconductor. The photocurrent is finite even when the photon energy is below the gap of GaAs and can be varied by applying a bias voltage between the n and p contacts. The observed phenomena can be explained by a generalized Franz–Keldysh model which takes into account the finite voltage drop inside the sample.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.99592
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  • 5
    Digitale Medien
    Digitale Medien
    Insulin Mediators and the Control of Pyruvate Dehydrogenase Complex (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 573 (1989), S. 0 
    Details
    ISSN: 1749-6632
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1749-6632.1989.tb15006.x
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  • 6
    Digitale Medien
    Digitale Medien
    Molecular and genetical analysis of the fructose-glucose transport system in the cyanobacterium Synechocystis PCC6803 (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 3 (1989), S. 0 
    Details
    ISSN: 1365-2958
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Medizin
    Notizen: Complementation for glucose transport capacity of deficient mutants from Synechocystis PCC6803 allowed the cloning of the corresponding gene, glcP. The protein predicted from one open reading frame (ORF) in the DNA sequence was 468 residues long. It showed 46–60% amino acid sequence homology and similarity in size and predicted structure (including twelve probable membrane-spanning regions) with a group of non-phosphorylating sugar transporters from mammals, yeasts and Escherichia coli. A second ORF, 64 base pairs downstream from glcP, was detected. Its function, dispensable under auto- and heterotrophic conditions, could not be determined. Genetic analysis of mutants confirmed that the resistance to fructose, acquired simultaneously with the deficiency in glucose transport, resulted from mutations in the glcP gene, whose approximate location could be determined.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-2958.1989.tb00272.x
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  • 7
    Digitale Medien
    Digitale Medien
    Physiological and genetic analysis of the glucose-fructose permeation system in two Synechocystis species (1988)
    Springer
    Archives of microbiology 149 (1988), S. 417-421 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Cyanobacteria ; Sugar transport ; Permeation mutants ; Fructose toxicity ; Heterotrophy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Fructose is toxic for Synechocystis PCC 6714 and 6803, strains which grow chemoheterotrophically on glucose. This toxicity, as well as fructose uptake, were inhibited by glucose or by its non-metabolized analogue 3-O-methyl-glucose. The results suggested that both sugars were transported by the same permeation system, the affinity for fructose, estimated from the corresponding K m and K i, being very low. The unicity of the permeation system was further established by the isolation of spontaneous mutants showing the expected pleiotropic phenotype, Glu−, Frur, transport−, and by the simultaneous re-acquisition of the relevant wild type characteristics in mutant cells transformed by wild type DNA. The genetic nature of this mutation is discussed in view of the impossibility to isolate spontaneously reversed wild type clones from the transport deficient mutants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00425581
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  • 8
    Digitale Medien
    Digitale Medien
    Dynamical evolution of the rotation of Venus (1988)
    Springer
    Earth, moon and planets 43 (1988), S. 275-287 
    Details
    ISSN: 1573-0794
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract By considering the torque of the bodily tides, the effect of the core-mantle viscous coupling and the torque of the atmospheric tides have been obtained by numerical calculation: the evolution of the spin angular velocity Ω♀ and the obliquity β of the Venus are calculated numerically with the step-variable Runge-Kutta method of 7th order; and 7 sets of the probable Cytherean spin evolution have been obtained. It is indicated that the present spin state of Venus is the result of long-term evolution within the reasonable ranges of some disposable parameters. The early spin period is between 7 h to 2 d and the corresponding obliquity is about 90 ° ~ 100 °. The effects of the torques of body and atmospheric tides and the core-mantle viscous coupling of Venus on its spin angular velocity could nearly cancel out each other about a billion years ago. Therefore, Venus could have been captured in a spin-orbit resonant state by the gravitational torque of the Earth on the permanent deformation part of Venus; and this resonant state has lasted up to the present time.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00117100
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  • 9
    Digitale Medien
    Digitale Medien
    The lunar mean moment of inertia and the size of the Moon's core (1988)
    Springer
    Earth, moon and planets 42 (1988), S. 179-184 
    Details
    ISSN: 1573-0794
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract In this paper the relation between the uncertainty of the Moon's mean moment of inertia δ(I/Ma 2) and that of the core density δπc is discussed with a two-layer model of the Moon - a mantle obeying Roche's law of the density distribution and a homogeneous core (Fe-core or Fe-FeS-core). When the uncertainty of I/Ma 2 is 0.0023 (that is the accuracy in present observation), a core with radius of 450 km will be appropriate to the limitation of δπc about 1 g cm−3. Considering the accuracy obtained in space explorations, and the compressibility and the quasi-homogeneity of the Moon, we suggest that the parameters C 20, β, γ, a, and GM of the Moon should define as primary constants, but C 22 and C/Ma 2 as derived constants. Therefore, the ratio of mass of Moon to that of Earth in the IAU (1976) system of astronomical constants will become a deducible constant.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00054545
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  • 10
    Digitale Medien
    Digitale Medien
    The dynamical flattenings of Mercury and Venus (1988)
    Springer
    Earth, moon and planets 41 (1988), S. 289-294 
    Details
    ISSN: 1573-0794
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The method which is used to calculate the dynamical flattenings % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqefm0B1jxALjhiov2D% aebbfv3ySLgzGueE0jxyaibaiiYdd9qrFfea0dXdf9vqai-hEir8Ve% ea0de9qq-hbrpepeea0db9q8as0-LqLs-Jirpepeea0-as0Fb9pgea% 0lrP0xe9Fve9Fve9qapdbaqaaeGacaGaaiaabeqaamaabaabcaGcba% Gaamisaiabg2da9iaacIcacaWGdbGaeyOeI0YaaSaaaeaacaaIXaaa% baGaaGOmaaaacaGGOaGaamyqaiabgUcaRiaadkeacaGGPaGaaiykai% aac+cacaWGdbaaaa!4717!\[H = (C - \frac{1}{2}(A + B))/C\] of the Earth and Moon meets with difficulties when it applies to Mercury and Venus. In this paper, after the calculation of the dimensionless moment of inertiaC/MR 2 by solving the Emden equation, the effectiveness of the method deriving dynamical flattening from the observed value of the Mercury's obliquity θ is analysed based on the resonance rotation theory. Some suggestions are made for the future space explorations. Finally, the ranges of dynamical flattening and of the obliquity of Venus are calculated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00113990
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