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991.
Fresh niobium hydroxide was first precipitated from NbF5 solution using an aqueous ammonium hydroxide under basic conditions. Then a simple procedure of mixing lithium and niobium hydroxides together and heating at a low temperature (400 °C) produced pure ultrafine single phase LiNbO3 (LN). In the literature, this is the lowest temperature so far reported on the formation of LN. The phase content and lattice parameters are determined by X-ray diffraction (XRD). The average particle size and morphology were studied by transmission electron microscopy (TEM). 相似文献
992.
V. V. Emtsev P. Ehrhart D. S. Poloskin K. V. Emtsev 《Journal of Materials Science: Materials in Electronics》2007,18(7):711-714
Production processes of electrically active defects in degenerate silicon subjected to 2.5 MeV electron irradiation at T = 4.2 K and T = 300 K have been studied. The production rates of primary and secondary defects in irradiated samples are analyzed on the basis
of the known properties of radiation-produced defects in Si. It has been demonstrated that a striking difference in the production
rates of electrically active defects in n- and p-Si under irradiation at cryogenic temperatures may be related to the different
fate of Frenkel pairs in both materials. The production rate of primary defects in degenerate Si was found to be between 1.5 cm−1 and 2 cm−1. 相似文献
994.
995.
Summary A simply supported beam with fixed ends and an attached strongly nonlinear spring is considered. As the forced bending vibrations
of the beam have moderate amplitudes, the stretching force is a nonlinear function of the deflection. The vibrations are presented
as a series with respect to the modes of the beam without attachment. Applying the Bubnov-Galerkin procedure, an infinite
system of ordinary differential equations is derived. Using the multiple scales method, the quasiperiodic vibrations in the
region of the combination resonance are analyzed in the paper. The system vibrations, when the nonlinear spring is attached
in different points, are analyzed. Applicability of the nonlinear spring for mitigation of a combination resonance is discussed. 相似文献
996.
The relation between the initial unbalance and the output signal of bridge circuits when acted upon simultaneously by the
physical factor being measured and the temperature of the surroundings when the bridge is supplied from a voltage or current
source is investigated. Analytic relations are obtained which explain the temperature dependence of the useful output voltage
under external physical action.
__________
Translated from Izmeritel’naya Tekhnika, No. 1, pp. 48–49, 2007. 相似文献
997.
Composite powder based on AlB has been obtained by crushing pieces of industrial-waste Al - B fiber composite material at room temperature. The original design of a high precision microhardness tester made it possible to estimate the properties of powder particles both in the near-surface layers and under them. The aluminum fraction in the powder was established to represent a new structurally nonhomogenous material with increased microhardness (1.5 GPa), which grows up to 4 GPa in the near-surface layers. This is caused by formation of defects and stable oxides on external and internal interfaces in the aluminum matrix during crushing. To optimize the process of AlB powder sintering, adhesion on clean and real Al - B and Al/Al interfaces at various temperatures was investigated. By sintering at 910 K, new ceramic materials have been obtained with a density of 2200 kg/m3 and a strength of 90 MPa. 相似文献
998.
B. Dagens A. Martinez D. Make O. Le Gouezigou J.-G. Provost V. Sallet K. Merghem J.-C. Harmand A. Ramdane B. Thedrez 《Photonics Technology Letters, IEEE》2005,17(5):971-973
Among the new semiconductor materials for telecom devices, the GaInNAs-GaAs structure presents interesting properties for low-cost applications, like high differential gain and high T/sub 0/. Another key aspect of the performance is the behavior of the GaInNAs-GaAs based lasers under high bit rate direct modulation. Here, we demonstrate the dynamic capabilities of GaInNAs-GaAs three-quantum-well ridge structure through 2.5-Gb/s directly modulated laser emission and transmission on standard fiber, in the temperature range 25/spl deg/C-85/spl deg/C. Besides transmission is demonstrated up to 10 Gb/s at 25/spl deg/C on the same fiber, without penalty and bit-error-rate floor. 相似文献
999.
P. A. Borodovskii A. F. Buldygin A. S. Tokarev E. V. Chernyavskii 《Russian Microelectronics》2005,34(5):316-324
A further investigation is conducted into a new microwave method for evaluating bulk lifetime in silicon ingots 相似文献
1000.
Peter Eaton Andrea Ragusa Caroline Clavel Cristina T Rojas Paul Graham Raúl V Durán Soledad Penadés 《IEEE transactions on nanobioscience》2007,6(4):309-318
Glyconanoparticles which present carbohydrate and amino groups motifs at their surface were produced. These particles were highly stable and soluble in aqueous solutions. The presence of the carbohydrate groups also allowed the inclusion of more strongly binding groups, without affecting solubility. The binding of a model DNA, plasmid by these nanoparticles was studied by atomic force microscopy, transmission electron microscopy, and gel electrophoresis. Significant differences between the nanoparticles based on their affinities for the DNA were found, with implications for their potential use as nonviral gene delivery agents. 相似文献