Mixture of probability distributions as a basic component in simulating measurement accuracy

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.     

单片机系统的动态加密技术

单片机系统产品的加密和解密技术永远是一个矛盾的统一体。然而 ,为了更好的保护好自己的单片机技术成果和知识产权 ,加大解密成本 ,研究新型加密技术仍是保护成果的主要手段之一。文中在讨论了传统的单片机系统加密和解密技术的基础上 ,提出一种实用而有效的动态加密技术的实现方案。     

Matrix mediated alignment of single wall carbon nanotubes in polymer composite films

Alignment of single wall carbon nanotubes (SWNT) in liquid crystalline (LC) polymer matrix imparting orientation to the nanotubes along the nematic director was studied by atomic force microscopy, measurements of electrical conductivity and Raman spectroscopy of the composite in the directions parallel and perpendicular to the nematic director. The composites were prepared through dispersion of SWNT with LC monomer in a common solvent, their alignment in nematic monomer and consequent UV polymerization of the monomer. The anisotropy of electrical and optical properties of the system depends strongly on the concentration of the nanotubes in the range of 1-10% SWNT being especially strong for smaller concentrations and negligible at higher loads. A simple semi-quantitative model is suggested to account for the orientational behavior of nanotubes in nematic matrices. It successfully describes the observed anisotropy of physical properties at microscale (up to 200 μm) in terms of anchoring of the polymer chains to the nanotubes surface and adjustment of the nanotubes orientation to the nematic direction due to such coupling. The increasing disorientation of the nematic domains at higher nanotubes loads is explained as a development of larger number of LC defects induced by the nanotubes in the nematic matrix due to their intrinsic nature of aggregation. The anisotropy of physical properties at macro scale (several millimeters) is much smaller and less dependable on SWNT concentration because differently oriented LC domains effectively wash out the anisotropy.     

扫描式X光机及DDS在其运动控制中的应用

扫描式X光机是一种高精度，高性能的新型医疗设备，其显著优点在于大大降低了患者所受X光辐射剂量，可直接得到患者清晰的X光数字图像，缩短出片时间，X光片资料存储方便，便于实现远程诊断，该设备对运动控制部分的匀速性，平稳性和多次扫描的位置重复性的要求均很高。本文主要针对其运动控制部分的结构特点，分析了影响运动性能的主要原因，并将直接数字频率合成器应用于调速，从而实现了对其运动控制部分的要求。     

改善PZT微位移器线性的一种方法

根据锆钛酸铅压电陶瓷的逆压电效应。设计了以８０３１单片机为核心的压电陶瓷堆微位移器提高了ＰＺＴ的线性，从而满足了在天文自适应系统中所要求的精确微位的应用。     

较大直径、低位错锑化铟单晶的研制

本文简要介绍了用ＴＤＫ－３６单晶炉拉制的较大直径（φ＝２５ｍｍ）、低位错（＜１００ｃｍ￣（－２））的锑化铟单晶的理论和实践。通过对晶体生长室内温场，特别是内外坩埚尺寸的调整及对循环水流量的控制，成功地拉制出较大直径、低位错的锑化铟单晶。     

32位单片机80960KB中断系统硬件资源分析

本文主要介绍３２位单片机８０９６０ＫＢ中断系统的硬件结构及其运行机理。     

α－Al_2O_3衬底上生长的GaN膜的光学性质

采用金属有机化学气相淀积（ＭＯＣＶＤ）方法生长了α－Ａｌ２Ｏ３衬底上外延的高质量的单晶ＧａＮ薄膜。Ｘ射线衍射光谱与喇曼散射光谱表征了ＧａＮ外延薄膜的单晶结构和单晶质量。透射光谱和光调制反射光谱定出了六角单晶ＧａＮ薄膜的直接带隙宽度和光学参数。     

双光子Jaynes－Cummings模型的亚泊松光子统计特性研究

本文利用量子电动力学理论和缀饰原于方法，对双光子Ｊａｍｅｓ－Ｃｕｍｍｉｎｇｓ模型中单模激光场的稳态亚泊松光子统计性质进行了系统研究。结果表明：激光上能级相对泵浦参量Ｘａ具有一个确定的阈值Ｘａｔ；当Ｘａ＞Ｘａｔ时，光场呈现亚泊松光子统计；而当Ｘａ＞＞Ｘａｔ时，光场将呈现出深度且完全恒定的亚泊松光子统计。     

RADIOACTIVE OR NATURAL TRACER。TECHNIQUES FOR LEAK DETERMINING OF DAM ABUTMENT

Infiltration and localization of preferential infiltration zones at the dam abutment are measured using radioactive tracer tests of flow in boreholes,meanwhile interconnection between boreholes and the energing water points is analysed.The theory and practice of radioactive tracer synthetic detective method are described to give methods and calculation formulae used under the condition of stable flow in single well to measure permeability coefficient and hydrostatic heads.Major single hole techniques including measurement for seepage line,velocity,rate of seepage flow and relationship of recharge of groundwater in aquifers are introduced briefly.The possibilities offered by natureal tracers are analysed,uincluding electric-conduct,pH-value and temperature of water as well as stable isotopes(D,^18O) and tritium.Furthermore,the sensibilities of this theory and methods were confirmed by detecting seepage flow field of Xinanjiang Dam.