排序方式: 共有200条查询结果,搜索用时 15 毫秒
51.
Xin Cun TANG Tian Duo LI College of Chemistry Chemical Engineering Central South University Changsha Shandong Institute of Light Industry Jinan 《中国化学快报》2005,16(8):1077-1080
Investigation on the solid diffusion process of intercalary species within insertion-host materials plays an important role in the energy storage and output of secondary batteries1. To determine the solid diffusion coefficient, several electrochemical techniques have been developed such as galvanostatic intermittent titration (GITT)2,3, electrochemical impedance spectroscopy (EIS)4,5, potential intermittent titration technique (PITT)6, and potential step chronoamperometry (PSCA)7, potenti… 相似文献
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本实验研究一种快速,简便的测定鸡肉中二氯二甲吡啶酚残留量的高效液相色谱法。本法采用微量化技术处理样品,以乙腈-氯仿为提取剂提取样品中残留的二氯二甲吡啶酚,提取液经挥发干后,在正已烷和硫酸钠水溶液两相间进行分配以去除脂类物质,然后再用乙腈-氯仿人中将二氯二甲吡啶酚提取出来,将有机相挥发至干,残渣定量溶解于流动相中,以RP-HPLC分离,紫外检测器于265nm波长下检测,外标法定量。空白鸡肉样品添加 相似文献
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一种新型红色荧光卟啉的合成、表征及光谱性质 总被引:12,自引:0,他引:12
对-N,N-二苯氨基苯甲醛与吡咯在丙酸中回流直流缩合得到了一种新化合物四(N,N二苯基对氨基)苯基卟啉(TDPAPPH2)。通过元素分析,^1H NMR,IR和UV-Vis表征了其结构,该化合物能在红光区发射荧光。与无取代的四苯基卟啉(TPPH2)和相应的四氨基卟啉(TAPPH2)比较发现,其紫外光谱和荧光光谱具有较大的吸收红移。结合该化合物的结构特点用分子轨道理论对这种光谱红移现象进行了探讨。 相似文献
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YUAN Jin bin NIE Li hua ** YAO Shou zhuo ** State Key Laboratory of Chemo/Biosensing & Chemometrics College of Chemistry Chemical Engineering Hunan University Changsha P. R. China 《高等学校化学研究》2003,(3)
IntroductionVitamin B1plays a very important role in theaction of certain coenzymes and the prevention ofsome diseases.Vitamin B1exists in an aqueous so-lution in two forms,i.e.,the double- protonatedform ata lower p H value and the single- protonatedform ata higher p H value.The distribution ratio ofthe two forms changeswith the variation ofp H val-ue of the solution tested. The accurate determina-tion of vitamin B1is very important in both foodand pharmaceutical areas.Various analytical m… 相似文献
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Yang Xiao Xiao Yan Zhang Qin Bo Wang Ze Tan Can Cheng Guo Wei Deng Zhi Gang Liu He Fei Zhang 《中国化学快报》2011,22(2):135-138
An attempt has been made to prepare terephthalic acid(TPA) by solvent-free oxidation of p-xylene(PX) with air over tetra(pchlorophenylporphinato) manganese chloride(T(p-Cl)PPMnCl) and cobalt acetate.The co-catalysis between T(p-Cl)PPMnCl and Co(OAc)2 has been discovered under solvent-free conditions.TPA yield could be increased significantly when T(p-Cl)PPMnCl and Co(OAc)2 were used together.The addition of T(p-Cl)PPMnCl into the reaction mixture over Co(OAc)2 significantly accelerated the rate-determining step of the oxidation process of PX to TPA.The effect of temperature on reaction was also investigated. 相似文献
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<正>We propose a new type of wavelength division demultiplexer composed of a photonic crystal waveguide with asymmetric corrugated exit surface.The focus displacement for different symmetric corrugated surfaces is relative to the intensity of the excited surface mode.By systematically investigating the effects of the parameters of the corrugated surface on the focus shift,we demonstrate an on-axis focus by a photonic crystal waveguide with an asymmetric corrugated exit surface at a specific wavelength.The precise equivalences of surface modes at each side of the exit surface are broken.Thus,for the light source with other wavelengths,the emerging beams are off-axis focused at different directions,similar to the function of a wavelength division demultiplexer. 相似文献
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Luo Zhiguo Shen JianhuaDept. of Math. Hunan Normal Univ. Changsha . E mail: luozg@mail. hunnu.edu.cn 《高校应用数学学报(英文版)》2000,(4)
§ 1 IntroductionDelay differential equations with piecewise constant arguments repressenta hybrid ofcontinuous and discrete dynamical systems and combine the properties of both differentialand difference equations.They have particular importance in control theory and certainbiomedical problems.Recently there has been a lot of activities concerning the oscillatoryproperties of solutions of such equations.See,for example[1~ 4 ] and the comprehensivesurvey paper[5] .Consider the linear delay … 相似文献
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有跳-扩散违约风险的可转换债券的定价 总被引:1,自引:0,他引:1
本文研究在跳-扩散违约风险模型下可转换债券的定价问题,假定股票价格服从对数正态分布,利用Martingale Pricing方法推导出其定价公式. 相似文献
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Xuan Yun Wang Su Qin Liu Ke Long Huang Qiu Ju Feng De Lai Ye Bing Liu Jin Long Liu Guan Hua Jin 《中国化学快报》2010,21(8):987-980
<正>With high surface area,open porosity and high efficiency,a catalyst was prepared and firstly employed in electrocatalytic reduction of CO_2 and electrosynthesis of dimethyl carbonate(DMC).The electrochemical property for electrocatalytic reduction of CO_2 in ionic liquid was studied by cyclic voltammogram(CV).The effects of various reaction variables like temperature,working potential and cathode materials on the electrocatalytic performance were also investigated.80%yield of DMC was obtained under the optimal reaction conditions. 相似文献