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21.
{X_n,n≥1)是标准高斯序列,T_(ij)=cov(X_i,X_j)。本文在强相依条件rijlog(j-i)→r∈(0,∞)(j-i→ ∞)下,得到了高斯序列的最大值M_n与标准化部分和S_n=sum from i=1 to n(X_i/(E(sum from i=1 to n X_i)~2)/(1/2)) 相似文献
22.
本文采用水热法一步合成了二硫化镍粉晶,利用X射线衍射(XRD),扫描电子显微镜讨论了样品N iS2粉晶的晶体结构及形貌,研究了X射线衍射峰积分强度以及半峰宽等随反应条件的变化,并分析了N iS2粉晶的合成机理. 相似文献
23.
在计算机辅助教学工作中,充分利用BASIC语言的人机对话功能和图形处理功能,可使教学程序更加形象直观,灵活方便。本文通过两则简短的教学子程序,和同志们交流探讨。 相似文献
24.
In this letter, using mult-half-wave structure and some chosen films optimized method, the long-wave infrared (LWIR) narrow-band pass filter is investigated, meanwhile the opposite of the substrate coated with long-wavelength pass film. The transmittance of design spectrum is more than 80% at wavelength region of 8.05 8.35 μm, and the average transmittance is less than 0.5% at wavelength region of less than 7.95 and 8.45 14 pro. The filter is prepared by thermal evaporation method, and plasma-assisted deposition technology. The experiment result shows that the average transmittance is about 75% in the transmission wavelength range, and the average transmittance of cut-off band is about 0.3%. The results show that multi-half-wave structure and some chosen films optimized method for the preparation LWIR narrow-band pass filter are feasible. The film system is simplified and is convenient to prepare the film. 相似文献
25.
The multilayer Laue lens (MLL) is a novel diffraction optics which can realize nanometer focusing of hard X-rays with high efficiency. In this paper, a 7.9 μm-thick MLL with the outmost layer thickness of 15 nm is designed based on dynamical diffraction theory. The MLL is fabricated by first depositing the depth-graded multilayer using direct current (DC) magnetron sputtering technology. Then, the multilayer sample is sliced, and both cross-sections are thinned and polished to a depth of 35-41 μm. The focusing property of the MLL is measured at the Shanghai Synchrotron Facility (SSRF). One-dimensional (1D) focusing resolutions of 205 nm and 221 nm are obtained at E=14 keV and 18 keV, respectively. It demonstrates that the fabricated MLL can focus hard X-rays into nanometer scale. 相似文献
26.
In recent years, SPOC in the campus has been one of the main directions of college curriculum reform. Analytical chemistry is a key component of teaching in chemistry and chemical engineering major. It plays an important role in cultivating students' practical ability, scientific literacy and innovative ability. This paper introduces the reform trials of the analytical chemistry course based on SPOC teaching platform in the chemistry teaching team of Changsha University of Science and Technology. The experience and problems in the teaching process, as well as the consideration on the future construction of analytical chemistry SPOC teaching are described. 相似文献
27.
The laser properties of the Nd:YGG crystal are investigated. The absorption spectrum from 500 to 90Onto and emission spectrum from 850 to 1400nm of Nd:YGG are measured. As much as 1.35 W output power of fundamental laser operating at 935 and 938nm with a slope efficiency of 15.7% and 105mW output power of frequency doubled blue laser are successfully obtained. 相似文献
28.
针对铌酸锂(LN)电光调Q开关性能一致性差、退压式调Q时无法完全关断光路的问题进行了系统研究.在闪光灯泵浦Nd:YAG激光系统中,对多块LN电光调Q开关的退压式电光调Q性能进行了对比测试,并从电光调Q理论出发,分析了光路无法关断的可能原因.在此基础上,利用X射线定向仪、锥光干涉法对各晶体的轴向偏差、光学均匀性进行了表征,首次发现了LN晶体的电光不均匀性,即感应主轴偏离理论上的45°方向、通光截面各处感应双折射不一致.通过对比实验,证实了电光不均匀性是造成光路无法关断、不同开关性能差异较大的主要原因. 相似文献
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