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991.
992.
The main problems in estimating the uncertainty due to the presence of impurities in the material: the absence in the documents of a unique definition of the quantity being measured – the fixed point temperature, the lack of agreed methods of realizing the fixed points and the insufficient justification of the equations used for the estimate, are analyzed. The results of a measurement of the melting point of gallium are presented, which differ in the conditions in which they were realized – with one and two liquid-solid interfaces and different solidification conditions, are presented. The reasons for the considerable difference between the values of the temperatures obtained in these experiments are discussed. 相似文献
993.
Progress in the area of fiber-optic sensors throughout the world since 1990 is analyzed. Current technical and market trends as well as the use of sensors in industry and health care are considered. Market forecasts for the use of fiber-optic sensors are given. 相似文献
994.
The possibility of optimum filtration of the radiation of a mercury arc lamp for subterahertz Hilbert-transform spectroscopy with a frequency-selective Josephson detector is demonstrated. Hilbert-transform spectroscopy was used for the first time for measuring the transmission spectrum of a high-pass filter. 相似文献
995.
V. G. Shengurov S. P. Svetlov V. Yu. Chalkov B. A. Andreev Z. F. Krasil'nik B. Ya. Ber Yu. N. Drozdov 《Inorganic Materials》2003,39(1):3-5
The Ge and Er depth profiles in Si1 – x
Ge
x
layers grown on Si(100) substrates by Si sublimation-source molecular-beam epitaxy in GeH4 were studied by secondary ion mass spectrometry. The results demonstrate that Ge facilitates Er incorporation into the growing Si–Ge layer. The Er dopant profile becomes sharper with increasing Ge content. The Ge profile also has rather sharp boundaries, indicating that there is no Ge surface segregation, which is attributable to the presence of adsorbed hydrogen, acting as a surfactant. 相似文献
996.
N. A. Cherkashin M. V. Maksimov A. G. Makarov V. A. Shchukin V. M. Ustinov N. V. Lukovskaya Yu. G. Musikhin G. E. Cirlin N. A. Bert Zh. I. Alferov N. N. Ledentsov D. Bimberg 《Semiconductors》2003,37(7):861-865
The effect of the growth temperature on the density, lateral size, and height of InAs-GaAs quantum dots (QD) has been studied by transmission electron microscopy. With the growth temperature increasing from 450 to 520°C, the density and height of QDs decrease, whereas their lateral size increases; i.e., the QDs are flattened. The blue shift of the photoluminescence line indicates decreasing QD volume. The observed behavior is in agreement with the thermodynamic model of QD formation. The effect of lowering the substrate temperature immediately after the formation of QDs on the QD parameters has been studied. On lowering the temperature, the lateral size of QDs decreases and their density increases; i.e., the parameters of QD arrays tend to acquire the equilibrium parameters corresponding at the temperature to which the cooling is done. The QD height rapidly increases with cooling and may exceed the equilibrium value for a finite time of cooling, which enables fabrication of QD arrays with a prescribed ratio between height and lateral size by choosing the time of cooling. 相似文献
997.
A study is made of the statistical characteristics of isotropic velocity and scalar fields in supply of the kinetic energy
of turbulence from the energy of the average flow. Two models based on the distributions of the kinetic turbulence energy
and the intensity of scalar-field pulsations by wave numbers and length scales are used for calculation of the statistical
characteristics of turbulent velocity and scalar fields. The calculation results are compared to the data of the direct numerical
modeling performed under the same initial conditions.
__________
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 1, pp. 148–154, January–February, 2006. 相似文献
998.
Sr-doped lanthanum cuprate was recently investigated as a potential cathode material for the intermediate temperature solid oxide fuel cell using yittria-stabilized zirconia as an electrolyte. The material thermal stability of cathode material against an electrolyte at an operating temperature plays an important role in the fuel cell's performance. In this study, the structural stability between Sr-doped lanthanum cuprate and 8 mol% yittria-stabilized zirconia was investigated by using the powder mixture and diffusion couple. The chemical reaction between these two materials in the temperature ranging from 800° to 1000°C was examined by X-ray diffraction analyses. The interfacial reaction behavior between electrode and electrolyte pellets of the reaction couple was examined by a grazing X-ray diffractometer, wavelength-dispersive X-ray analysis, and an electron probe microanalyzer. No reaction products were observed as these two materials co-fired at 800°C. The reaction products of pyrochlore La2 Zr2 O7 and perovskite SrZrO3 were formed when the specimens were heat treated at over 900°C. Because of the formation of these reaction products, the CuO was precipitated. Furthermore, an excess of SrZrO3 formation leads to the phase decomposition of perovskite Sr-doped lanthanum cuprate to La2− x Sr x CuO4 and CuO due to a decrease in strontium concentration in Sr-doped lanthanum cuprate. 相似文献
999.
A stochastic model is proposed for a basic mechanism in the formation of uncertainties in physical quantity measurements.
__________
Translated from Izmeritel'naya Tekhnika, No. 1, pp. 12–17, January, 2006. 相似文献
1000.
Yu. V. Alekseev G. Yu. Alekseev V. A. Bityurin A. V. Plaskeev 《Protection of Metals》2006,42(6):526-531
A simplified topokinetic dissolution model of a solid taking into account the correlation between the dissolution rate and
the atomic surface topography enables one to interpret a linear (in semilogarithmic coordinates) segment of the steady-state
curves of the active anodic dissolution of metals. Its slope corresponds to the product of a concentration of kinks and the
elementary reaction rate, both of which exponentially depend on the potential, rather than a simple (Tafel) elementary rate
of the atom dissolution at a semi-crystal kink.
Original Russian Text ? Yu.V. Alekseev, G.Yu. Alekseev, V.A. Bityurin, A.V. Plaskeev, 2006, published in Zashchita Metallov,
2006, Vol. 42, No. 6, pp. 568–573. 相似文献