空间重离子入射磷化铟的位移损伤模拟

磷化铟(InP)具备电子迁移率高、禁带宽度大、耐高温、耐辐射等特性,是制备空间辐射环境下电子器件的重要材料.随着电子器件小型化,单个重离子在器件灵敏体积内产生的位移损伤效应可能会导致其永久失效.因此,本文使用蒙特卡罗软件Geant4模拟空间重离子(碳、氮、氧、铁)在InP材料中的输运过程,计算重离子的非电离能量损失(n...     

Non-Rayleigh photon statistics of superbunching pseudothermal light

Superbunching pseudothermal light has important applications in studying the second-and higher-order interference of light in quantum optics.Unlike the photon statistics of thermal or pseudothermal light is well understood,the photon statistics of superbunching pseudothermal light has not been studied yet.In this paper,we will employ single-photon detectors to measure the photon statistics of superbunching pseudothermal light and calculate the degree of second-order coherence.It is found that the larger the value of the degree of second-order coherence of superbunching pseudothermal light is,the more the measured photon distribution deviates from the one of thermal or pseudothermal light in the tail part.The results are helpful to understand the physics of two-photon superbunching with classical light.It is suggested that superbunching pseudothermal light can be employed to generate non-Rayleigh temporal speckles.     

利用LC-MS-MS等方法分析确定黄连总碱提取物中微量未知物的结构

中药黄连中所含的多种生物碱中主要成分是小檗碱、棕榈碱、药根碱和黄连碱等,为了分析鉴定黄连总碱中微量生物碱,运用ESI-MS-MS,FaB-MS-MS以及LC-MS-MS等多种质谱方法对由甲醇提取的总碱部分提取物进行了分析研究,并结合LC-NMR对其中1种未知物的结构给予了确认.     

具分布时滞Cohen-Grossberg神经网络周期解的存在性与吸引性

利用数学分析方法,讨论了具分布时滞Cohew-Grossberg神经网络周期解的存在性与吸引性,推广了已有的结论．     

一种基于Web的分类体系学习算法

领域分类结构的抽取已成为本体工程和本体学习的关键部分,提出一种新的分类结构学习算法,将Web作为知识获取的语料库,运用迭代方法抽取相关语言学模式,再利用语言学模式抽取分类结构,并采用改进的互信息方法对结果进行评价和过滤,最后通过实验对该分类学习算法的性能进行评价.实验表明：算法具有良好的跨领域性,在准确率和召回率方面也有改善.     

基体石墨的孔隙结构及其对单质Ag扩散的影响

高温气冷堆燃料元件的基体石墨是一种多孔复合材料,是燃料元件的主要组成部分,其结构影响燃料元件的性能和裂变产物在燃料元件中的扩散。 本文利用压汞法表征基体石墨的孔隙结构,并讨论了基体石墨制备工艺中最大压制压强与热处理过程对孔隙结构的影响。 结果表明,基体石墨大孔孔径分布为6001900 nm,高温热处理使基体石墨的总孔隙率、中值孔径、大孔孔容均减小;基体石墨热处理样品的大孔孔容随最大压制压强的增加而呈线性减少,热处理过程单质Ag在石墨基体中的扩散速度与大孔孔容变化具有正相关性。     

普通化学多媒体网络课程的开发与应用

普通化学网络课程是教育部“新世纪网络课程建设工程”项目 ,该课件使用Flash作为网络多媒体开发工具 ,采用了矢量图形技术、MP3声音格式和流式技术等 ,开发出的软件体积小 ,适于网络传输。该课件用于课堂教学和学生自学 ,收到了良好的教学效果     

硒芳香杂环化合物的光谱和电化学性质

用紫外光谱，荧光光谱和循环伏安法研究了含硒芳香杂环化合物（苤硒脑）在不同溶剂中的谱学和电化学性质，对不同分子结构或取代基的苤硒脑化合物的性质进行了比较，并初步探讨了溶剂对苤硒脑化合物谱学性质的影响规律。     

构建芳叔胺-BPO氧化还原引发体系实现苯乙烯在硅胶微粒表面的高效接枝聚合

首先使用偶联剂γ-氨丙基三甲氧基硅烷(AMPS)对微米级硅胶微粒进行了表面改性,制得表面带有伯胺基的改性微粒SiO2-AMPS,接着使4-(二乙氨基)水杨醛(DEAS)与微球SiO2-AMPS发生席夫碱反应,制得表面含有芳叔胺基的改性微粒SiO2-DEAS.使改性微粒SiO2-DEAS表面的芳叔胺基团与溶液中的BPO构成氧化-还原引发体系,实现了油溶性单体苯乙烯(St)在硅胶微粒表面的引发接枝聚合,制得了高接枝度(27 g/100g)的接枝微粒SiO2-DEAS-g-PSt.采用红外光谱(FTIR)、扫描电镜(SEM)及热重分析(TGA)等方法对接枝微粒SiO2-DEAS-g-PSt进行了表征.在此基础上,重点研究了主要因素对芳叔胺-BPO体系引发St接枝聚合的影响.研究结果表明,与在固体微粒表面引入可聚合双键的"穿过接枝"(grafting through)法相比,芳叔胺-BPO体系引发的接枝聚合,由于活性位点位于载体表面,故具有高的接枝度,是油溶性单体的一种高效率的表面引发接枝法.为制得高接枝度的接枝微粒SiO2-DEAS-g-PSt,适宜的温度为50℃,适宜的BPO用量为单体的3 wt%左右,适宜的单体浓度为10 wt%.     

An amperometric biosensor based on covalent immobilization of ascorbate oxidase on biocompatiable and low-toxic poly(thiophene-3-acetic acid) matrix

The biocompatiable and low-toxic poly（thiophene-3-acetic acid）（PTAA） matrix was successfully electrosynthesized in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate（BmimPF₆） in comparison with the electrosynthesis of PTAA matrix in acetonitrile（ACN）.Ascorbate oxidase（AO） was used as a model for the development and application of biosensor.Vitamin C（VC） biosensors were facilely fabricated by the covalent immobilization of AO molecules on PTAA matrices electrosynthesized in ACN containing tetrabutylammonium tetrafluoroborate and BmimPF₆, respectively.Electrochemical impedance spectroscopy,scanning electron microscopy and FTIR spectroscopy indicated that AO molecules were covalently immobilized on PTAA matrices.Parameters of the as-obtained biosensors such as working potential,pH and temperature have been optimized.The amperometric biosensor based on PTAA matrix electrosynthesized in BmimPF₆ exhibited wider linear range,lower detection limit,higher sensitivity and bioaffinity,and better operational and storage stability than that electrosynthesized in ACN under optimal conditions.The as-obtained biosensor based on PTAA matrix electrosynthesized in BmimPF₆ was employed for the detection of VC content in commercial juices,and the result was close to the data given by manufacturers.Excellent results indicate that the PTAA matrix electrosynthesized in ionic liquid is a promising platform for the covalent immobilization of biologically-active species and the development of biosensors.