改性β沸石催化剂的再生动力学研究

在内循环无梯度反应器中进行烧炭试验，采用库贯实验设计法安排试验点，研究了改性β沸石催化剂FX－01烧炭再生反应动力学，得出碳消耗速率及氢消耗速率的烧炭反应的本征动力学模型。结果表明，氢比碳易于燃烧，不同催化剂和不同反应体系积炭的燃烧特性不同。     

Localized Surface Plasmon Resonance Promotes Metal–Organic Framework-Based Photocatalytic Hydrogen Evolution

Combining metal nanoparticles (NPs) featured with localized surface plasmon resonance (LSPR) with metal–organic framework (MOF)-based photocatalysts is a novel means for achieving efficient separation of electron–hole pairs. Herein, the Au@NH₂-UiO-66/CdS composites are successfully synthesized by encapsulating Au NPs with LSPR into the NH₂-UiO-66 nanocage, further growing CdS NPs on the surface of the NH₂-UiO-66, which exhibits higher photocatalytic activity in hydrogen evolution reaction under visible-light irradiation than that of NH₂-UiO-66/CdS and CdS, respectively. Transient absorption measurements reveal that MOF is not only a transit station for electrons generated from CdS to Au, but also a receiver for hot electrons generated from plasmonic Au in Au@MOF/CdS composites. Thus, the LSPR-induced hot electron transfer from Au NPs is an important manifestation to prolong the carrier lifetime and enhance the photocatalytic performance. This work provides insights into investigating the photoinduced carrier dynamics of nanomaterials with LSPR effects for enhancing the MOF-based photocatalytic performance.     

人脑半监督学习机理分类法

针对NN(nearest neighbor)和kNN(k-nearest neighbor)方法在标记样本较少时,分类正确率不高的缺陷,根据人脑分类样本时,自觉地利用未标记样本的半监督学习机理,提出一种人脑半监督学习机理分类方法。该方法利用未标记样本间的近邻关系,减少了标记样本数量对分类正确率的影响程度。在MNIST手写体数字库和ORL人脸库上的样本分类实验表明,在标记样本数较少的情况下,该方法的分类正确率比NN和kNN方法高得多。     

面向人名消歧任务的人名识别系统

CLP2010(CIPS-SIGHAN Joint Conference on Chinese Language Processing)的人名消歧评测的任务是个 聚类问题:对给定的一组文档,按照文档中出现的指定查询词所指向的人进行聚类.由于是用"字"串匹配的方法从新华社的语料库中抽出所有含有该查询词的文档.所以对于这个...     

Chemical sensor based on microfabricated wristwatch tuning forks

We report here a chemical sensor based on detecting the mechanical response of a thin (approximately 10-microm) polymer wire stretched across the two prongs of a wristwatch quartz tuning fork (QTF). When the fork is set to oscillate, the wire is stretched and compressed by the two prongs. The stretching/compression force changes upon adsorption of analyte molecules onto/into the polymer wire, which is detected by the QTF with pico-Newton force sensitivity. An array of such sensors with different polymer wires is used for simultaneous detection of several analytes and for improvement of pattern recognition. The low cost (approximately 10 cent) of the QTF, together with that an array of QTFs can be driven to oscillate simultaneously and their resonance frequencies detected with the same circuit, promises a high performance, low cost, and portable sensor for detecting various chemical vapors. We demonstrate here detection of parts-per-billion-level water, ethylnitrobenzene, and ethanol vapors using the QTF arrays.     

Alkylation of Benzene with Long-Chain Olefins Catalyzed by Fluorinated β Zeolite

The effects of fluorination on H zeolite and alkylation of benzene with long-chain olefins catalyzed by fluorinated zeolite are investigated. The lifetime of the catalysts depends on the surface area and pore volume rather than acidity. When the fluorine content is 0.5%, the lifetime improves by 30%, when the catalyst has maximum specific surface area and pore volume.     

锂离子动力电池包保温性能的优化设计

为了解决电动汽车冬季续航里程严重缩水的问题,进行了一系列保温优化设计.针对某款动力电池包,首先分析了其在低温下的"痛点"和散热路径,在不降低模型精度基础上,进行了内部保温和外部保温仿真设计和分析.以优化的内外保温相结合的方案为蓝本,进行了保温性能仿真验证.结果表明,保温工况下电池包的低温"痛点"主要集中在靠近端板的位置.在该部位采取加强隔热的措施,就能提升电池包最低温度,减小温差.     

大型调相机动态响应下的电磁转矩分析

凭借着强无功支撑能力,大型调相机在特高压直流输电(LCC-HVDC)中发挥着愈发重要的作用,本文分析了大型调相机的动态响应特性,推导了调相机的电磁转矩表达式,得出了动态响应下电磁转矩变化与定子电流、转子励磁电流变化趋势相关的结论.文中通过PSCAD/EMTDC建立了含同步调相机的LCC-HVDC模型,对受端电网单相接地短路与三相短路下调相机的动态响应和电磁转矩变化进行了仿真验证,发现机端电压下降时,随着调相机的无功动态响应,电磁转矩与定子电流、转子励磁电流变化趋势相同,呈现先增大后减小的变化趋势,同时对于三相对称故障引起的电磁转矩变化表现出一定的对称性,为大型调相机的运行与电网故障的判断监控提供了一定的理论基础.     

基于强化学习的直流微电网分布式经济下垂控制

针对直流微电网在传统下垂控制下整体运行成本偏高且存在电压静态偏差的问题,提出一种基于强化学习的完全分布式经济下垂控制策略.通过分布式一致性算法寻找系统最优经济运行点,并利用偏差调整和Adam算法优化经济下垂系数,以提高计算的速度与效率;通过改进强化学习原理进行电压的二次优化控制.利用MATLAB/Simulink搭建具有不同运行成本单元的直流微电网仿真模型,结果验证了所提策略的有效性和优越性以及即插即用特性.