基于小波分解系数的贝叶斯人脸识别方法

本文给出了贝叶斯人脸识别方法中匹配准则的多个近似表达式及一种实用的快速计算方法.在此基础上,利用反对称双正交小波变换的微分算子功能,提出了一种利用两幅人脸图象的小波变换系数差作为模式矢量的贝叶斯人脸识别方法,并利用AR人脸图象库进行了实验.实验结果表明本文方法与基于图象灰度的类似方法相比,识别率提高8%左右.此外本文方法也提供了一条在图象压缩数据域中实现人脸识别的可能途径.     

坩埚下降法生长白宝石晶体的研究

本文报道了坩埚下降法生长大尺寸白宝石单晶.我们使用大尺寸异型钼坩埚,高纯氧化铝原料,在中性气氛下,结晶区温度梯度为25～30℃/cm,生长速度为0.8～1.8mm/h,生长方向选C面[0001]取向,成功生长出直径80mm,高度90mm的完整透明的白宝石单晶,在300～5500nm范围内,其光学透过率均在80;以上.实验中采用高性能保温材料使生长过程所需加热功率由20kW下降到15kW,能耗降低达25;;采用双回路加热系统,提高温场稳定性,缩短晶体生长周期.晶体的主要缺陷为顶部(生长后期)出现有5～10mm淡黄色色带(经在氧化性气氛中退火后已消除)和底部有细丝状条纹.     

氮笼N12的量子化学研究

采用量子化学从头算方法研究了7个氮笼N₁₂,其中包括以前文献中研究过的两个氮笼N₁₂.在RHF/6-31G^*理论水平下进行全构型优化、振动频率分析和热化学计算.计算结果表明,7个结构均是势能面上的局域极小点.N₁₂(D_3d)是所有7个笼状异构体中最稳定的.能量分析表明,如果这些分子能够被合成,将会成为潜在的高能量密度材料.     

高效液相色谱法测定血浆中表阿霉素浓度

报道了高效液相色谱法测定血浆中表阿霉素浓度的实验方法。采用μＢｏｎｄａｐａｋＣ＿（１８）色谱柱,正磷酸、甲醇、乙腈、异丙醇为流动相。荧光检测器检测,激发波长为４５０ｎｍ,发射波长为５３０ｎｍ。血浆经离心后,取血清,用甲醇沉淀蛋白。方法的平均相对回收率为９９．４％±４．６％,日内和日间平均ＲＳＤ小于５％和６％。最低检测限为３ｎｇ。本方法快速、准确,灵敏度高。     

IN SITU STM STUDY OF THERMAL ANNEALING OF Au THIN FILMS:AN INVESTIGATION ON DECAY OF NANOMETER Au CLUSTERS AND 2D ISLANDS

An in situ, ultrahigh vacuum scanning tunneling micrmcopy(UHV STM) study of thermal annealing of gold thin films is presented in this paper. The gold thin films was heated and annealed in the UHV chamber in the temperature range From room temperature to maximum of 300℃, while a consecutive STM imaging was performed on the surface of the gold films during the heating and annealing. The STM results showed that the surface corrugation changes became more apparent after the temperature increased above 100℃, whereas much smoothened surface and large Au (111) crystalline terrace(>200nm) formed at temperature of 160℃ of above. Betides the surface morphology change, our images clearly revealed the melting of multilayer gold clusters and shrinking of monolayer gold islands in a nanometer scale. It was shown that the decay of the gold clusters and islands constitute the microscopic processes contributing to the thermal activated surface morphology change. A classical theory of mass flow kinetics was adopted in analyzing the decay processes. The results showed that surface diffusion is the dominate mechanism in the thermal annealing of the gold thin films. This study presents the first microscopic investigation of thermal annealing processes of metal thin films observed by in situ and real-time STM.     

（±）-HypoglycinA的全合成

采用Wittig试剂与环氧氯丙烷和多聚甲醛构建亚甲基环丙烷结构单元，利用2，5-二乙氧基-3，6-二氢吡嗪引入氨基酸结构单元，通过6步反应成功实现了天然植物毒素HypoglycinA外消旋体的全合成，总收率3．2％。中间体和Hypoglycin A的结构经^1HNMR表征。对反应中的问题进行了分析和讨论。     

A Note on Fundamental Limit of Quantum Dynamics Rate

The unified bound on the fundamental limit of quantum dynamics rate, as quietly recently obtained by Levitin and Toffoli [Phys. Rev. Lett. 103 （2009） 160502], is improved and refined. The improvement may be arbitrarily large in certain cases. In particular, this puts a limit on the operation rate of quantum gates allowed by quantum mechanics.