A characterization of certain discrete exponential families

For independent random variables X and Y, define % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqefm0B1jxALjhiov2D% aebbfv3ySLgzGueE0jxyaibaiGc9yrFr0xXdbba91rFfpec8Eeeu0x% Xdbba9frFj0-OqFfea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs% 0dXdbPYxe9vr0-vr0-vqpWqaaeaabiGaciaacaqabeaadaqaaqGaaO% qaaiaabofaruWrL9MCNLwyaGqbciaa-bcacqGHHjIUcaWFGaGaa8hw% aiaa-TcacaWFzbaaaa!4551!\[{\rm{S}} \equiv X + Y\]. When the conditional expectations % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqefm0B1jxALjhiov2D% aebbfv3ySLgzGueE0jxyaibaiGc9yrFr0xXdbba91rFfpec8Eeeu0x% Xdbba9frFj0-OqFfea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs% 0dXdbPYxe9vr0-vr0-vqpWqaaeaabiGaciaacaqabeaadaqaaqGaaO% qaaiaadweacaGGBbqefCuzVj3zPfgaiuGajaaqcaWFNbGccaGGOaGa% amiwaiaacMcacaGG8bGaam4uaiaac2facqGHHjIUcaWGHbGaaiikai% aadofacaGGPaaaaa!4BC4!\[E[g(X)|S] \equiv a(S)\]and % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqefm0B1jxALjhiov2D% aebbfv3ySLgzGueE0jxyaibaiGc9yrFr0xXdbba91rFfpec8Eeeu0x% Xdbba9frFj0-OqFfea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs% 0dXdbPYxe9vr0-vr0-vqpWqaaeaabiGaciaacaqabeaadaqaaqGaaO% qaaiaadweacaGGBbGaamiAaiaacIcacaWGybGaaiykaiaacYhacaWG% tbGaaiyxaiabggMi6kaadkgacaGGOaGaam4uaiaacMcaaaa!4894!\[E[h(X)|S] \equiv b(S)\]are given, then under certain assumptions, the density function of X has the form of u(x)k()e^ax, where u(x) is uniquely determined by the functions a(·) and b(·).     

分子筛组装单质半导体碲的拉曼光谱

无机介孔材料MCM41是高有序,直孔道介孔分子筛,具有孔径约4nm的一维均匀孔道,孔壁厚约1nm,介孔体积可达40%,是一种很理想的组装材料主体。半导体碲位于第Ⅵ族,其六方相的晶格排列呈螺旋链状结构。本文采用固相合成反应方法,将单质半导体碲成功地组装在MCM41介孔分子筛中。在组装体中,单质半导体碲保持着六方相的晶体结构,其拉曼晶体振动表现出纳米晶体的结构特征。真空热处理实验表明,组装体具有良好的热稳定性。Te的六方相和所具有的独特的螺旋链状结构使Te分子很容易进入MCM41的直孔道内,同时MCM41均匀而规则的直孔道限制了Te螺旋链的随机排列,因而被组装在直孔道内的Te能螺旋链式生长,形成一维半导体纳米晶体,排列均匀,尺寸单一,具有稳定的空间构型     

稀氢氟酸中硅表面氢终端的原位拉曼光谱研究

本文用共焦显微拉曼系统原位观察了Ｓｉ（１００）表面氢终端原子在稀氢氟酸中的变化过程。研究表明：在硅片浸入氢氟酸溶液的初期,表面主要被硅和三个氢原子的结合体（Ｓｉ Ｈ３）以及硅和两个氢原子的结合体（Ｓｉ Ｈ２）所覆盖。随着腐蚀过程的延长,Ｓｉ Ｈ３越来越少,Ｓｉ Ｈ２的信号不断增强,并且,硅和单个氢原子的结合体（Ｓｉ Ｈ）的信号也开始出现。最终,硅表面主要被Ｓｉ Ｈ２所覆盖,有少量Ｓｉ Ｈ３和Ｓｉ Ｈ键。本文还表明,拉曼光谱用来原位观察半导体材料表面终端原子键在溶液中的变化是很有用的工具     

随机共振实验

介绍了随机共振现象的基本原理、模拟电路,给出了一组实验结果,并绘制了实验曲红,分析了随机共振产生的原因。     

Energy Eigenstates of a Quantum Gate System

We report exact solutions of the Poyatos–Cirac–Zoller quantum gate system withtwo trapped ions [Phys. Rev. Lett. 81, 1322 (1998)]. It is the superposition ofentangled states among the pure states of two harmonic oscillators and describesa mixed mode involving the center-of-mass and relative motions withcommensurable frequencies. Theoretical analysis of the exact solutions showsthat for a given trapping frequency the relative motion cannot be laser-cooled.     

Resonant magnetopolaron effects in GaAs/AlGaAs multiple quantum well structures

A detailed experimental study of electron cyclotron resonance (CR) has been carried out at 4.2 K in three modulation-doped GaAs/Al_0.3Ga_0.7As multiple quantum well samples in fields up to 30 T. A strong avoided-level-crossing splitting of the CR energies due to resonant magnetopolaron effects is observed for all samples near the GaAs reststrahlen region. Resonant splittings in the region of AlAs-like interface phonon modes of the barriers are observed in two samples with narrower well width and smaller doping concentration. The interaction between electrons and the AlAs interface optical phonon modes has been calculated for our specific sample structures in the framework of the memory-function formalism. The calculated results are in good agreement with the experimental results, which confirms our assignment of the observed splitting near the AlAs-like phonon region is due to the resonant magnetopolaron interaction of electrons in the wells with AlAs-like interface phonons.     

Ca8Mg(SiO4)4Cl2中Ce3+和Eu2+的光谱性质和能量传递

首次合成了Ｃｅ＾３＋和Ｅｕ＾２＋共激活氯硅酸镁钙Ｃａ８Ｍｇ（ＳｉＯ４）４Ｃｌ２：Ｃｅ＾３＋，Ｅｕ＾２＋高效绿色荧光粉，报道了它们的漫反射光谱、激发和发射光，观察到氯硅酸镁钙中Ｃｅ＾３＋ Ｅｕ＾２＋     

吉布斯自由能的农业应用和生物学意义

吉布斯自由能作为基本力学函数,在农业和生物学中有着重要的应用,在现代农业中,由吉布斯自由能的水势要概念,已成为判断农业系统水份动转的主要判据;在生物学中,吉布斯自由能作为生命体系赖以生存的能量,直接维持和驱动着生命体系的运转,本文讨论了吉布斯自由能的农业应用和生物学意义。     

扫描近场光学显微镜光纤锥中导波反射特性

利用局部模耦合模型理论上分析了扫描近场光学显微镜光纤的光场性质,给出光纤维中存在的正,反向传播的基模场微分方程,以及基模反向耦合系数的数值计算结果,其最高反射系数达１％左右。这种反射光可起着光纤维激光器谐振腔输出端镜的作用。