A novel high-performance counter electrode for dye-sensitized solar cells

A novel Pt counter electrode for dye-sensitized solar cells (DSC) was prepared by thermal decomposition of H₂PtCl₆ on NiP-plated glass substrate. The charge-transfer kinetic properties of the platinized NiP-plated glass electrode (Pt/NiP electrode) for triiodide reduction were studied by electrochemical impedance spectroscopy. Pt/NiP electrode has the advantage over the platinized FTO conducting glass electrode (Pt/FTO electrode) in increasing the light reflectance and reducing the sheet resistance leading to improve the light harvest efficiency and the fill factor of the dye-sensitized solar cells effectively. The photon-to-current efficiency and the overall conversion efficiency of DSC using Pt/NiP counter electrode is increased by 20% and 33%, respectively, compared to that of using Pt/FTO counter electrode. Examination of the anodic dissolution and the long-term test on the variation of charge-transfer resistance indicates the good stability of the Pt/NiP electrode in the electrolyte containing iodide/triiodide.     

基于双天线GNSS/SINS组合的风速测量运动补偿方案设计

以基于浮标平台的动态风速测量为背景,根据运动姿态补偿的原理和实际需要,设计了一套双天线GNSS/SINS组合姿态测量系统,采用卡尔曼滤波实现信息融合,通过在卡尔曼滤波的观测量中引入双天线GNSS输出的航向角信息,解决了惯性系统航向角可观测性较弱的问题,并通过实验验证了系统的有效性。实验结果表明,该运动补偿设计方案能够提高平台姿态测量的精度和稳定性,准确测量平台的姿态信息,并有效降低平台运动对风速测量的影响,风速测量误差低于4%,满足了海洋浮标观测的需求。     

非零速启停的低功耗步进电机控制器研究

为了优化步进电机开环控制性能,对非零速启停的加减速曲线算法及其低功耗硬件逻辑实现进行了研究。针对零速启停的加减速曲线存在控制性能难以充分发挥的问题,提出了一种非零速启停的步进电机线性加减速曲线算法,将加减速过程划分为四种转动模式,可构建任意的线性速度剖面。首先理论推导了四种加减速转动模式的控制脉冲周期;其次结合流水线设计思想优化加减速曲线算法的硬件逻辑模型,在FPGA中设计了步进电机控制器IP核,并采用门控时钟等低功耗IC设计技术实现了IP核的低功耗;最后,搭建了实验平台进行验证。实验结果表明,IP核可以实现四种转动模式的非零速启停控制,实现了高实时、高精度驱动,提升了20%的控制性能,电路面积优化约30%,功耗降低53%,验证了方案的可行性与有效性。     

Ring-opening polymerization of ethylene oxide by anion initiation using sulfadiazine as parents compound

A new kind of anion initiator using sulfadiazine as the parent compound was prepared by the reaction of sulfadiazine with epoxy ethylene, and then the metal potassium. The structure of the intermediate was characterized in detail by NMR, MS, UV, IR, and DSC. Ring-opening polymerization of epoxy ethylene could be carried out by this initiation system. The molecular weight of the polymerized product, polyethylene oxide with a sulfadiazine end group (PEO_sf), is in the range of 3000–4000. © 1995 John Wiley & Sons, Inc.     

助催化剂对BCZ-108催化剂聚合行为的影响研究

在铝钛物质的量比为25、50、100、150、200、300条件下,研究丙烯聚合用BCZ-108催化剂的聚合行为及聚丙烯的主要性能,并与常规应用的NA催化剂进行对比。结果表明,随着铝钛物质的量比的增大,两种催化剂的聚合反应速率的衰减越来越快,聚丙烯的立体定向性越来越低,熔点越来越低,分子量分布越来越宽;BCZ-108催化剂的聚合活性比NA催化剂高30%以上;两种催化剂的聚合活性在铝钛物质的量比为50时达到最高,此时BCZ-108催化剂的活性为1 212 g·g^-1,NA催化剂的活性为907 g·g^-1。     

Assessment of Bitumen Re c overy from the Athabasca Oil Sands Using a Laboratory Denver Flotation Cell

A methodology was developed in this study to evaluate the effect of operating parameters on the processability of oil sands using small‐scale laboratory experimental devices. By subtracting bitumen recovered to the froth by entrainment with water, the concept of “true flotation recovery” is proposed to describe bitumen recovery resulting from bitumenbubble attachment. The experimental results indicated that “true flotation recovery” is a more sensitive and meaningful marker than overall bitumen recovery to evaluate the processability of oil sands using small‐scale laboratory test units.     

聚酯高效催化剂缩聚反应动力学研究

研究了常规的Sb2 O3 、复合催化剂和C - 94三种催化剂对于PET缩聚反应的宏观动力学。结果表明 ,在相同条件下复合催化剂和C - 94的催化活性明显高于常规的Sb2 O3 催化剂 ;C -94的表观活化能明显高于复合催化剂和常规催化剂 ,其催化PET缩聚反应过程的温度效应显著 ;在有效搅拌条件下 ,三种催化剂在高真空阶段仍有较高的催化活性 ,过程是化学反应控制的。     

基于词向量与TextRank的关键词提取方法

针对词汇语义的差异性对TextRank算法的影响进行了研究,提出一种基于词向量与TextRank的关键词抽取方法。利用FastText将文档集进行词向量表征,基于隐含主题分布思想和利用词汇间语义性的差异,构建TextRank的转移概率矩阵,最后进行词图的迭代计算和关键词抽取。实验结果表明,该方法的抽取效果相比于传统方法有明显提升,同时证明利用词向量能简单而有效地改善TextRank算法的性能。     

基于排列熵和支持向量机的癫痫发作预测研究

针对癫痫发作给病人带来的巨大伤害,为临床治疗留下足够空余时间,提出一个可以预测癫痫发作的系统模型。对21名癫痫病人进行研究,提取具有较低算法复杂度的排列熵构成特征向量,将其输入支持向量机（support vector machine,SVM）训练出学习模型,用来识别发作期样本,利用投票机制充分考虑病人差异来判断所处状态,最终实现癫痫的实时预测。结果表明,其中81%的发作可以提前平均50多分钟预测到,且具有较低的误报率。为癫痫发作预测系统的理论研究打下坚实基础。     

PbNb2O6基压电陶瓷的高温介电性能研究

本文在PbNb2O6基础上采用Ba^2＋取代Pb^2＋离子,并通过添加Cr2O3、Y2O3、Sm2O3、Nd2O3和CeO2等氧化物进行掺杂改性,研究不同掺杂剂对PbNb2O6陶瓷材料结构的影响,寻找提高压电性能及居里温度的途径.试验结果表明,掺杂后的偏铌酸铅显微结构发生了变化,适量的掺杂可获得压电性能和工艺稳定性能很好,且居里温度较高（420℃～600℃）的改性PbNb2O6系压电陶瓷,可分别满足350℃和500℃以上高温应用环境的要求.