Total Ionization Dose Effects on Charge Storage Capability of Al_2O_3/HfO_2/Al_2O_3-Based Charge Trapping Memory Cell

Because of the discrete charge storage mechanism, charge trapping memory(CTM) technique is a good candidate for aerospace and military missions. The total ionization dose(TID) effects on CTM cells with Al_2O_3/HfO_2/Al_2O_3(AHA) high-k gate stack structure under in-situ 10 keV x-rays are studied. The C-V characteristics at different radiation doses demonstrate that charge stored in the device continues to be leaked away during the irradiation,thereby inducing the shift of flat band voltage(V_(fb)). The dc memory window shows insignificant changes, suggesting the existence of good P/E ability. Furthermore, the physical mechanisms of TID induced radiation damages in AHA-based CTM are analyzed.     

非晶材料与物理近期研究进展

由于结合了金属和玻璃的特性,非晶合金表现出许多新奇和优异的力学和物理性质,在很多领域具有广泛的应用前景.非晶合金具有连续可调的成分、简单无序的原子结构、丰富多变的材料性质,为研究非晶态物理中的许多共性科学问题提供了理想的模型材料.块体非晶合金的发展更是将玻璃和液体及其相关科学问题的研究推进到凝聚态物理和材料科学的研究前沿.中国科学院物理研究所极端条件物理重点实验室亚稳材料合成、结构及性能研究组(EX4组)近二十年来一直致力于非晶材料和物理的研究,在新型非晶合金的制备、物性以及相关机理的研究上取得了许多重要成果.本文介绍团队最近在非晶材料和物理机理方面取得的研究成果,包括非晶合金的动力学行为和调控、非晶合金的表面动力学、功能应用以及材料探索新方法等.     

Simulation study on characteristics of long-range interaction in randomly asymmetric exclusion process

In this paper we investigate the dynamics of an asymmetric exclusion process on a one-dimensional lattice with longrange hopping and random update via Monte Carlo simulations theoretically. Particles in the model will firstly try to hop over successive unoccupied sites with a probability q, which is different from previous exclusion process models. The probability q may represent the random access of particles. Numerical simulations for stationary particle currents, density profiles, and phase diagrams are obtained. There are three possible stationary phases: the low density(LD) phase, high density(HD) phase, and maximal current(MC) in the system, respectively. Interestingly, bulk density in the LD phase tends to zero, while the MC phase is governed by α, β, and q. The HD phase is nearly the same as the normal TASEP,determined by exit rate β. Theoretical analysis is in good agreement with simulation results. The proposed model may provide a better understanding of random interaction dynamics in complex systems.     

Fabrication of a 256-bits organic memory by soft x-ray lithography

This paper reports a procedure of soft x-ray lithography for the fabrication of organic crossbar structure. Electron beam lithography is employed to fabricate the mask for soft x-ray lithography, with direct writing technology to lithograph positive resist, polymethyl methacrylate on the polyimide film. Then Au is electroplated on the polyimide film. Hard contact mode exposure is used in x-ray lithography to transfer the graph from the mask to the wafer. The 256-bits organic memory is achieved with the critical dimension of 250~nm.     

Pentacene Organic-Thin-Film Field-Effect Transistors

We have fabricated organic thin-film transistors using the small-molecule polycyclic aromatic hydrocarbon pentacene as an active material. Devices were fabricated on glass substrates by using rf-magnetron sputtered amorphous aluminium as the gate electrode, and gelatinized polyimide as the gate dielectric with physical vapour grown pentacene thin films pasted on it as the active layer, then using rf-magnetron sputtered amorphous aluminium as the source and drain contacts. Field effect mobility and threshoM voltage is O.092cm^2/Vs and 14.5 V, respectively. On-off current ratio is nearly 10^3.     

基于变形镜的气动光学效应仿真实验研究

基于高速飞行器流场光传输数据和变形镜系统,提出了一种气动光学效应半实物仿真方法。根据流体力学、统计、几何和物理光学等理论,建立远场目标的光学传输模型,获得气动光学效应引起的目标光波的波前畸变数据,控制变形镜系统调制光波来仿真生成畸变。完成了初步验证,建立了一个超音速飞行模型(马赫数Ma=5)并进行了仿真实验,计算了实验的波前仿真误差,并分析了成像偏移和模糊特性。对高速飞行中的气动光学效应进行仿真,在实验室条件下实现对相关成像系统性能和校正技术的测试。     

对《全日制义务教育数学课程标准》实验过程中存在问题的思考

自2001年9月起，到目前为止全国已有500多个县(区)进行了《全日制义务教育数学课程标准》(实验稿)^[1](以下简称《标准》)的课程改革的实验．《标准》汲取了国内数学教育改革的优秀成果，注意到国外数学教育发展的趋势，提出了涉及数学课程观、数学课程价值观、数学的学习过程、     

基于探测信号叠加的推扫式压缩多光谱关联成像

针对推扫模式下多光谱关联成像重构图像模糊、信噪比低问题,提出了一种利用探测信号叠加提高重构图像信噪比的多光谱关联成像方案.该方案基于稀疏约束关联成像光谱相机实验系统,通过单次曝光获得一帧探测信号,对前后帧连续探测信号进行错位叠加,计算出系统总探测矩阵,结合标定测量矩阵,采用压缩感知算法得到待测目标物体重构图像.数值模拟和实验结果表明:适当延迟曝光时间可以提高系统重构图像质量;相同曝光时间条件下,利用探测信号错位叠加的推扫10帧重构图像信噪比明显高于单帧多光谱重构图像.     

由均匀染色导出的强Chernoff界

本文研究了相关变量的Chernoff问题. 利用相关变量构造图的方法, 利用均匀染色的结果, 获得了更强的Chernoff界, 推广了Chernoff不等式在相关随机变量的不等式下的界.     

国际天然气价格驱动因素的结构性变化

页岩气开采技术的大规模应用增加了非常规天然气供应潜力,对国际天然气市场供需格局产生了较大冲击。本文利用带结构断点的协整检验、时变系数模型和条件误差修正模型等方法系统地研究了天然气价格与原油价格的动态关系,以及库存、天气和投机等短期因素对气价变化的影响。结果显示,国际天然气价格与原油价格间的协整关系在2005年飓风季与2008年金融危机期间发生了结构性变化,而且原油价格对天然气价格的影响强度呈现倒U型结构。此外,极端天气、突发性事件及投机等短期因素对气价存在显著的短期影响。不过,随着天然气供应出现过剩局面,天然气价格对这些短期因素的敏感性已大幅降低。