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991.
C. Czekalla J. Lenzner A. Rahm T. Nobis M. Grundmann 《Superlattices and Microstructures》2007,41(5-6):347
In this paper, we report stimulated emission from a zinc oxide (ZnO) microcrystal grown by carbothermal evaporation observed by spatially resolved photoluminescence (PL) and high excitation spectroscopy (HES). 相似文献
992.
993.
将导电裂纹视为铁电体的击穿模型。导出了当有一裂纹和一电极成垂直接触时的储能公式,由此推得当裂纹开裂一单位面积时的驱动能量,当此能量大于铁电体的表面能时,就是临界击穿的条件,从而可以求出临界电压或临界冲击波强度。并将结果和其它文献作了比较。 相似文献
994.
I. K. Vereshchagin 《Journal of Applied Spectroscopy》1998,65(1):146-148
Time changes in the intensity of luminescence of zinc sulfide electroluminophores induced by rectangular unidirectional voltage
pulses are considered. The origin of luminescence spikes that are observed under application and removal of voltage is discussed.
Results of studies of these spikes and microscopic observations show that the light spikes observed under application of voltage
can be ascribed to migration of holes that appear in barriers during the previous voltage pulse into the crystal interior.
Moscow State University of Railway Transport, 15, Obraztsov St., Moscow, 101475, Russia. Translated from Zhurnal Prikladnoi
Spektroskopii, Vol. 65, No. 1, pp. 140–142, January–February, 1998. 相似文献
995.
This paper proposes some diagnostic tools for checking the adequacy of multivariate regression models including classical
regression and time series autoregression. In statistical inference, the empirical likelihood ratio method has been well known
to be a powerful tool for constructing test and confidence region. For model checking, however, the naive empirical likelihood
(EL) based tests are not of Wilks’ phenomenon. Hence, we make use of bias correction to construct the EL-based score tests
and derive a nonparametric version of Wilks’ theorem. Moreover, by the advantages of both the EL and score test method, the
EL-based score tests share many desirable features as follows: They are self-scale invariant and can detect the alternatives
that converge to the null at rate n
−1/2, the possibly fastest rate for lack-of-fit testing; they involve weight functions, which provides us with the flexibility
to choose scores for improving power performance, especially under directional alternatives. Furthermore, when the alternatives
are not directional, we construct asymptotically distribution-free maximin tests for a large class of possible alternatives.
A simulation study is carried out and an application for a real dataset is analyzed.
相似文献
996.
997.
强场对Au4团簇性质的影响 总被引:1,自引:1,他引:0
采用与时间相关的局域密度泛函 (TDLDA/B3LYP)方法研究Au4团簇的几何构型、分子轨道能级分布和激发能在强激光场中的变化.计算结果表明:电场不能改变Au4团簇的几何构型,随着电场的增加,电离势和电子亲和势增加,而费米能级和能隙减小.通过比较不同电场强度下激发能,指出要产生超短波脉冲或实现X射线软化,强激光场中的团簇的高次谐波是一种可能的途径. 相似文献
998.
J.L. Sánchez Ll J.T. Elizalde-GalindoJ.A. Matutes-Aquino 《Solid State Communications》2003,127(7):527-530
High coercivity nanostructured YCo5 powders were successfully prepared by mechanical milling of as-cast alloys and subsequent vacuum annealing. Almost single phase YCo5 alloys, obtained by arc melting, were processed by high energy mechanical milling using a SPEX 8000 mill. After 4 h of milling, powders become nearly amorphous. DSC scans revealed the existence of an irreversible broad exothermic transition with a maximum at 516 °C associated with the crystallization process. Annealing in high vacuum at 800 °C during 2.5 min led to the formation of YCo5 nanoparticles with an average particle size of 12 nm. A high intrinsic coercivity of 7.23 kOe together with a σr/σs ratio of 0.75 were obtained. 相似文献
999.
1000.
RIBLL终端LASCAR闪烁体阵列探测器研制进展 总被引:1,自引:1,他引:0
介绍了RIBLL终端LASCAR闪烁体阵列探测器的工作原理和结构特点. 描述了为满足放射性核束实验的要求而对阵列所作的重要改进. 给出了LASCAR构型优化改造的工作设想和实施步骤. The principles and structure characteristics of LASCAR scintillator array detector at RIBLL terminal are described. Special emphases are laid upon the latest progress for the development of LASCAR array detector to meet the requirements of the RIB experiments. The working plan and steps for optimizing configuration of the LASCAR multi unit neutron scintillator array detector are also presented. 相似文献