基于二元高钴材料的锂离子聚合物电池开发

对一种新型的二元高钴材料进行了物理、化学、形貌及晶体结构指标测试,并应用该材料作为正极进行了锂离子聚合物电池的开发,对使用该材料体系的锂离子聚合物电池进行了比容量、倍率性能、不同温度放电性能、高温贮存性能、循环性能以及安全性能等综合测试,测试的结果表明,这种二元高钴材料完全满足锂离子聚合物电池的要求。     

基波平衡原理的推广

注入网络的基波电流iS1=0。则可由Gi(Um,ωS)=0和Bi(Um,ωS)=0求出基波解的频率和幅值(ωS,Um)。如果有n对合理的正实数(ωSi,Umi,i=1,2,3….n≠∞),同时满足式Gi=0和Bi=0,则原网络会对应地建立n个周期振荡。以上情况被称为基波解严格存在。若由式Gi≤0,Bi≤0解出的频率和幅值有无限多组解(ωS,Um),分布在一定连续较广范围内,这表明基波解不但在更加广泛的范围内存在,且有向负载送出实功与虚功的能力。含多个平衡点的非线性网络,能够在相空间建立多个座标体系分析网络的全局稳定性。不同的参考体系,应得出相同的结论。但用多个不同的座标体系能够发现相图性状的变化规律。     

FCOB器件在热循环载荷下的界面层裂研究

界面层裂是塑封半导体器件的主要失效模式之一。采用通用有限元软件MSC.MARC,研究了FCOB(基板倒装焊)器件在热循环(–55~+125℃)载荷作用下,底充胶与芯片界面的层裂问题。结果表明:底充胶与芯片界面最易出现分层,分层扩展的位置都在该界面的边缘拐角处;如果分层导致底充胶开裂,开裂的方向大约是35°。     

Cayley图连通圈的一个代数性质研究

探讨Cayley图连通圈成为Cayley图的一个充分条件.利用代数学中关于群扩展理论的基本知识证明了如果Carley图连通圈中的Cayley图是具有完全旋转的Cayley图时,则相应的Cayley图连通圈可表示为一个半直积群对应的Cayley图,并通过几个实例进行说明验证.     

70 dB Dynamic Range CMOS Wideband Digital Variable Gain Amplifier for AGC in DVB-T/H Receivers

This paper presents a novel variable gain amplifier (VGA) design which is applied in the automatic gain control loop of digital video broadcasting (DVB) receivers designed for standards DVB-T/H. The VGA is composed of three cascaded tunable gain stages to provide a 70 dB dynamic range with 2 dB gain steps. Each gain stage is based on a digital variable gain amplifier (DVGA) which is composed of a plurality of gain blocks (GBs) and a fully differential degeneration amplifier (FDDA). The GBs of the DVGA are digitally controlled current mirrors. A common-mode feedback circuitry is used to stabilize the FDDA by providing a stable common-mode voltage. Physical measurements on silicon show that the gain error is merely 0.55 dB given a 70 dB tuning range. This work was supported by National Science Council, Taiwan, under contract nos. NSC96-2628-E-110-019 and NSC96-2920-E-110-001.     

某医学院附属医院洁净手术部空调设计

介绍了工程的空调设计,包括设计指标,空调冷热源,水系统,风系统,自动控制系统等.总结了工程中的节能设计.     

受冻融环境混凝土的应力-应变全曲线试验研究

为研究受冻融循环作用的混凝土受压应力-应变关系,按照GBJ 82-85规定的快速冻融试验方法,对3批共85个尺寸为100 mm×100 mm×300 mm的混凝土棱柱体试件进行了冻融循环,试件的变化参数为混凝土立方体抗压强度和冻融循环次数;然后对试件进行了单轴抗压破坏试验.结果表明:随着冻融循环次数增加,混凝土的受压应力-应变曲线渐趋扁平,峰值应力降低,峰值应变增大;冻融循环次数相同时,混凝土立方体抗压强度高的试件,其峰值应力降低程度和峰值应变增大程度小于混凝土强度低的试件.回归试验结果,提出了适用于立方体抗压强度为30～50 MPa的受冻融循环作用混凝土的应力-应变全曲线方程及确定其参数的公式.     

房屋建筑物安全管理问题与对策

针对建筑业目前普遍存在的重建设,轻维修的现状,分析了我国现阶段房屋建筑物在服役期内的安全影响因素及房屋安全管理的模式,提出建立全寿命期的房屋安全管理体系、创新安全管理制度并建立起与城市危机管理相结合的房屋安全预警预案。     

兰炭尾气经济高效发电技术方案分析

结合某兰炭生产公司的具体情况,分析了兰炭尾气高温超高压锅炉发电、内燃机发电、燃气-蒸汽联合循环发电的技术经济特点,并对各发电方案的适用性进行了简单阐述,为类似节能改造项目提供参考。     

Thermal energy harvesting performance in 0.94Bi0.5Na0.5TiO3-0.06BaZr0.2Ti0.8O3: AlN composite ceramics based on the Olsen cycle

The pyroelectric effect provides an efficient route to convert low-grade waste heat into electricity. (Bi_0.5Na_0.5)TiO₃-based ceramic is one of the most attractive lead-free pyroelectric candidates due to its high polarization. However, the low breakdown strength (BDS) restricts its ability to achieve a high polarization, hindering the application for thermal energy harvesting based on the Olsen cycle. In this work, by incorporation of AlN into BNT-BZT ceramics to form the BNT-BZT: AlN composites, the BDS is enhanced from 160 kV cm⁻¹ to 260 kV cm⁻¹, leading to a high energy density of 1.54 J cm⁻³ which is ∼5 times that of the pristine BNT-BZT. The reason for the high energy harvesting performance is due to the addition of AlN that can depress the conductivity of the matrix, resulting in the high BDS that permits high electric fields to be applied on the samples to induce high polarization that changes pronouncedly with temperature.