高速低功耗SRAM中灵敏放大器的设计

本文对比分析了运放型、交叉耦合型和锁存器型灵敏放大器三种不同的SRAM灵敏放大器的基本结构并通过仿真比较了它们的优缺点,在此基础上设计了读出放大时间在最坏情况下需0.5 ns,静态维持功耗约为0.1 mW的SRAM灵敏放大器.     

基于最大色度着色的频率指配方法

本文主要介绍了基于最大色度着色的频率指配方法,并给出相关算法和程序流程图,最后将其应用到了实际的频率指配问题中.     

IBM建立大中华区计算中心助企业实现高效信息运营

2008年6月24日,IBM在北京IBM中国创新中心举行了以“携手云端 创新未来”为主题的IBM大中华区云计算中心启动仪式。未来,该中心将帮助大中华地区的客户设计和部署自己的云计算设施和程序。     

Glass Forming Ability of Metallic Glasses Evaluated by a New Criterion

The glass-forming ability （GFA） of Cu-Zr binary alloys is evaluated using the existing criteria based on calorimetric parameters, and poor relations are found. Therefore, another parameter Tτκ defined as Tκ/Tl, in which Tκ is the Kauzmann temperature and Tl the equilibrium liquidus temperature, is proposed. It exhibits good agreements with the experimental data of the Cu-Zr system and other representative bulk metallic glass formers so long as classifying them into strong or fragile category. It is suggested that kinetic effects are irrelevantly incorporated in the GFA analysis in the previous work.     

Numerical Calculation of SAW Propagation Properties at the x-Cut of Ferroelectric PMN-33%PT Single Crystals

Surface acoustic wave （SAW） properties at the x-cut of relaxor-based 0.67Pb（Mg1/3Nb2/3）O3-0.33PbTiO3 （PMN- 33%PT） ferroelectric single crystals are analyzed theoretically when poled along the [001]c cubic direction. It can be found that PMN-33%PT single crystal is a kind of material with a low phase velocity and high electromechanical coupling coefficient, and the single crystal possesses some cuts with zero power flow angle. The results are based on the material parameters at room temperature. The conclusions provide device designers with a few ideal cuts of PMN-33%PT single crystals. Moreover, choosing an optimal cut will dramatically improve the performance of SAW devices, and corresponding results for crystal systems working at other temperatures could also be figured out by employing the method.     

不同提取方法对菟丝子总黄酮和金属元素锌的含量比较研究

分别采用常规回流提取法、石油醚脱脂-索氏提取法和微波辅助萃取法对中药菟丝子进行提取;以芦丁为对照品,紫外分光光度法测定提取物中总黄酮的含量;原子吸收光谱法测定提取液中金属元素锌的含量,以总黄酮的含量和金属元素锌的含量为考察指标,明确金属元素锌的提取与黄酮类总含量之间的关系。结果表明,3种提取方法中,微波辅助萃取法具有高效、省时等优点,提取效果最好,锌元素的含量与总黄酮的含量成正比。     

Diode-pumped self-Q-switched Cr,Nd:YAG laser with 7-W average output power

We report a diode-pumped self-Q-switched 1064-nm Cr,Nd：YAG of 16-18 ns. The maximum average output power up to 7 W, 3370, is obtained in a simple and compact linear cavity by using transmittance of 1570. The laser operates at TEM00 mode with a laser with pulse duration in the range corresponding to a slope efficiency of a plane-concave output coupler with a pump power of 14.2 W.     

A Facile Synthesis of Silver-Coated Composite Particles by Swelling Surface Method

We report a facile and rapid method for fabrication of composite particles consisting of a polystyrene (PS) core and a uniform silver shell. The process involves the PS colloid surface swelling, the anchoring of silver ions and nanoparticles onto the surfaces, and the subsequent growth of metal seeds in a short period. The present approach has the advantages of simplicity and high efficiency. The TEM images show the morphology of the obtained PS core-silver shell particles, and their chemical composition and crystallinity are analysed by x-ray diffraction. To our knowledge, this is the first study based on swelling PS surface for synthesis of silver-coated PS particles and may be implemented for preparing other metal-coated PS particles.     

Gd替代对La0.6-xGdxSr1.4MnO4磁性和输运性质的影响

随着x的增加，多晶La0.6-xGdxSr1.4MnO4（x=0, 0.1, 0.2, 0.4, 0.6）的零场冷却 曲线从类自旋玻璃型转变成顺磁型，并且每条零场冷却 曲线都有一在20K的拐点。这一行为可以从Gd和Mn各自对材料总磁性的不同贡献来理解。另外，在所有的样品中，从100K到室温，都观察到了热激活导电行为。由于Mn-Mn间强的反铁磁耦和，直到外场达到50 kOe，都没有观察到明显的磁电阻效应。     

离散的五次非线性薛定谔方程的精确孤子解

利用推广的双曲函数法，我们研究了离散的五次非线性薛定谔方程。当方程的系数满足某种约束关系时，我们得到了新的局域解。这些解包括亮孤子解，暗孤子解，相位交替变化的亮孤子解和相位交替变化的暗孤子解。