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961.
Dhar A 《Physical review letters》2002,88(24):249401; discussion 249401
962.
Schaaf P. Milosavljevic M. Dhar S. Bibic N. Lieb K.-P. Wölz M. Principi G. 《Hyperfine Interactions》2002,139(1-4):615-621
At present, there is an increasing interest in the iron di-silicide phase -FeSi2, which is supposed to be a direct band gap semiconductor and one of the most promising materials for silicon-based optoelectronics, e.g., light-emitting devices, solar cells, and photo detectors. But this phase is very difficult to be produced. Here, the successful direct synthesis of this phase by ion beam mixing of Fe/Si bilayers at temperatures in the range of 400 to 600°C is reported. The aim of the experiments was to achieve a complete reaction of the deposited Fe layer with the Si substrate that results in the formation of a pure, single-phased -FeSi2 surface layer. The obtained silicide layers, their structure and composition are investigated by conversion electron Mössbauer spectroscopy (CEMS), Rutherford backscattering spectrometry (RBS), and X-ray diffraction (XRD). The fraction of the -FeSi2 formed is determined by CEMS as function of ion species, energy, fluence and temperature. Complete growth and formation of a single-phased -FeSi2 layer was achieved by 205 keV Xe ion irradiation at a fluence of 2×1016 ions/cm2 at 600°C. 相似文献
963.
The holographic recording characteristics of a photopolymer-nanoporous-glass composite are reported. An M/# of 3.2 is measured in this medium by angle multiplexing of a series of plane-wave holograms. In addition, the dimensional stability of the material is demonstrated by the negligible Bragg detuning of a set of angle-multiplexed holograms recorded with varying grating tilt angles and by the relative insensitivity of the detuning to changes in temperature. 相似文献
964.
We have performed axially symmetric Skyrme force time-dependent Hartree-Fock calculations for the 136Xe + 209Bi system at E(lab) = 940 MeV and 1130 MeV. The evolution of the nuclear geometry is studied in detail. The calculated final fragment kinetic energies, scattering angles, and charges are in good agreement with experiment, but the fragment charge dispersion is greatly underestimated. Studies of head-on collisions for 900 MeV ? E(lab) ? 2000 MeV show no evidence for fusion and indicate a dramatic transparency for E(lab) ? 1500 MeV. 相似文献
965.
Raj K. Kaul 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1963,14(6):704-713
Zusammenfassung Die vorliegende Arbeit befasst sich mit den radialen und axialen Dehnungen in einem einseitig unbegrenzten elastischen Stab mit kreisförmigem Querschnitt. Die Oberfläche des Stabes ist in radialer Richtung frei von Spannungen; in normaler Richtung wird an dem einen Ende eine Druckspannung als zeitlicher Sprungimpuls eingeprägt, wobei die Scherspannung an diesem Ende stets zu Null angenommen wird. Die exakte Lösung wird dargestellt durch komplexe Laplace-Umkehr-Integrale, welche für grosse Fortpflanzungsentfernungen asymptotisch gelöst werden. Insbesondere werden Lösungen gefunden für die Umgebung der Vorläufer der Welle und für die Anstiegsflanke der Druckwelle. 相似文献
966.
A new method of monitoring specific high-order optical susceptibilities of nonlinear media via angularly-resolved emission in a phase-matched multiwave mixing configuration is presented. This technique, which can be viewed as the creation by two optical beams of a strongly anharmonic absorption or index grating, and the simultaneous exploration of higher Bragg-diffraction orders by a third wave, is demonstrated here in the case of gas media near optical resonance. 相似文献
967.
968.
M. C. Rath S. K. Sarkar V. K. Wadhawan R. Verma I. M. L. Das R. Dąbrowski M. Tykarska R. Dhar 《Opto-Electronics Review》2008,16(4):399-403
Electron beam irradiation studies on liquid crystal material 5CB have been carried out at a temperature where the compound
exists in the isotropic liquid phase. In situ time-resolved spectroscopic characterization was carried out during the irradiation.
Three different transients were observed during the 2-μs electron pulse. After about 50 μs, only one transient species was
found to be present, which has an absorption peak at 360 nm. Radiolysed sample exhibits a broad absorption at ∼400 nm. The
dielectric measurements show that even a low level of irradiation results in a dramatic increase in the component of dielectric
permittivity normal to the long axes of the molecules ε⊥′, and a corresponding decrease in the dielectric anisotropy (Δε′=ε∥′−ε⊥′ ). These studies show that 5CB is prone to substantial radiation damage on exposure to the beam of high-energy electrons. 相似文献
969.
S. Shanmuga Sundara Raj Bohari M. Yamin Ahmed M. A. Boshaala M. T. H. Tarafder Karen A. Crouse Hoong‐Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):1011-1012
In the crystal structure of the title compound, C14H12N2O2, the molecule lies about a twofold axis; two carbonyl groups and the H atoms of the N—N bond are in a trans orientation with respect to each other. In the crystal, each molecule is linked to the other and viceversa by intermolecular N—H?O hydrogen bonds between the amide hydrogen and the O atoms of neighbouring molecules to form two ten‐membered rings, each of which has the graph‐set motif C4R(10). This extends as a polymeric chain along the c axis. 相似文献
970.