Synthesis,electrolyte properties and solar cell performance of hyperbranched poly(aryl-ether-urea)s

Hyperbranched poly(aryl-ether-urea)s with phenyl, N,N-dimethylamino ethyl and polyethylene oxide end-groups linked through urethane group – HBPEU-1, HBPEU-2 and HBPEU-3 respectively – were synthesized from an AB₂-type blocked isocyanate monomer and characterized by FT-IR, ¹H-NMR, SEC-MALLS, TGA and DSC techniques. The molecular weight of the polymers were found to be ranged from 4.9 × 10³ ? 1.96 × 10⁴ g/mol. The TGA results showed that the polymers decompose between 175°C – 220°C. In the DSC curves, HBPEU-1 and HBPEU-3 showed T_g at 160°C and 53°C respectively, whereas HBPEU-2 did not showed clear T_g. All the three polymers were converted into polymer electrolytes by doping with LiI/I₂. The doped polymers showed remarkably high ionic conductivity, up to 222 – 277 times compared to the un-doped polymers and the highest conductivity was observed with doped HBPEU-2. The TiO₂ based dye-sensitized solar cells (DSSCs) were fabricated using the doped polymer electrolytes and their performance was tested; HBPEU-2 showed good performance by yielding energy conversion efficiency (η) of 4.5%.     

一类偏差分方程的振动性

主要研究了偏差分方程pu_(m+2),n+u_(m,n+2)+qu_(m+1,n)-u_(m,n+1)+ru_(m,n)=0,解的振动性,其中参数p,q,r是实数,m,n为非负整数.     

On the Lê–Milnor fibration for real analytic maps

In this paper, we study the topology of real analytic map‐germs with isolated critical value , with . We compare the topology of f with the topology of the compositions , where are the projections , for . As a main result, we give necessary and sufficient conditions for f to have a Lê–Milnor fibration in the tube.     

On separating a fixed point from zero by invariants

Assume a fixed point v∈V^G can be separated from zero by a homogeneous invariant f∈𝕜[V]^G of degree p^rd, where p>0 is the characteristic of the ground field 𝕜 and p,d are coprime. We show that then v can also be separated from zero by an invariant of degree p^r, which we obtain explicitly from f. It follows that the minimal degree of a homogeneous invariant separating v from zero is a p-power.     

ITS示范工程对城市交通畅通性的贡献率研究

通过分析城市交通畅通性的影响因素及其与ITS(智能交通系统)的关系,挖掘ITS对城市交通畅通性的贡献率指标.搜集实证研究对象数据,采用灰色预测模型预测贡献率指标的数值,将ITS示范工程实施前后的数值进行对比,计算得到ITS示范工程对城市交通畅通性的贡献率.由贡献率结果判断ITS示范工程对城市交通畅通性的作用及ITS示范工程的实施效果如何,为未来ITS的发展提供相应的参考建议.     

横观各向同性体应力波传播问题的特征分析

本文根据广义特征理论,对横观各向同性体轴对称弹性波传播问题进行了理论分析。提出了一个简化特征分析的方法,这种方法将成为应用特征线法求解各类各向异性应力波问题的一个突破口。     

低应变速率下形状记忆合金的特性实验研究

形状记忆合金以其特有的形状记忆效应和超弹性,被广泛应用于医学、航空和建筑防震。在耗能性机构中,需要形状记忆合金能够在变速率条件下工作。为了获得非静态条件下的行为特性,比较静态和非静态条件下形状记忆合金的行为特性的差异,本文采用一种新的分析方法,即以形状记忆合金的特性参数为对象,来分析不同应变速率对形状记忆合金特性的影响。在不同的应变速率(0.0005/s,0.001/s,0.005/s,0.01/s,0.05/s,0.1/s)下,对50.8at%-Ni-Ti记忆合金丝的形状记忆效应和超弹性特性进行了实验研究。在低应变速率范围内,由实验结果得到:随应变速率增大,两种特性行为中的各纯相的杨氏模量保持不变;拉伸过程相变起始和终了临界应力会增大,卸载过程相变起始和终了临界应力会减小,滞后环面积增大;相变硬化系数在形状记忆效应行为中会增大,而在超弹性行为中基本不变。     

中心集中力作用下圆薄板的固有频率—载荷特征关系

本文讨论了中心集中静载作用下圆薄板在非线性弯曲静平衡构形附近的微幅自由振动,其静平衡问题采用问题的精确解在此基础上,用伽辽金法获得了其最低固有频率——载荷特征关系.所得结果可供这类谐振弹性元件设计中参考.     

心脏与血管的相互影响

心脏与血管的相互影响早就引起生理学家们的兴趣，但其在临床医学上的广泛应用则是近几年的事．这主要归功于两大生物力学成就，一是应甩泵功能曲线和时变弹性元描述心脏功能，另一是应用输入阻抗来描述血管功能．本文系统地总结和评述了２０多年来国际上关于心脏与血管相互影响的研究发展概况．     

基于CUDA的有限元矩阵并行装配算法研究

构建航天飞行器的结构有限元模型是准确模拟飞行仿真、完成飞行器在轨飞行阶段结构故障监测和诊断的基础。采用细长体飞行器简化梁模型，提出新的基于CUDA（Compute Unified Device Architecture）的有限元单元刚度矩阵生成和总刚度矩阵组装算法。依据梁单元矩阵的对称性，结合GPU硬件架构提出并行生成算法并进行改进。为有效减少装配时间，在装配过程中采用着色算法，提出了基于GPU（Graphics Processing Unit）共享内存的非零项组装策略，通过在不同计算平台下算例对比，验证了新算法的快速性。数值算例表明，本文算法的求解效率较高，针对一定计算规模内的模型可满足快速计算与诊断的实时性要求。