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41.
Jiaqi Guo Xinwei Wang Lijun Zhang Tao Wang 《Applied Physics A: Materials Science & Processing》2007,89(1):153-156
In this work, the thermal diffusivity of single polyacrylonitrile (PAN) wires with diameters from 4.62 μm down to 324 nm is
measured by using our recently developed transient electro-thermal technique. The wires span from 23 μm to 126.2 μm in our
measurement. Since PAN wires are dielectric, a thin Au film is coated on the surface of the wires to make them conductive.
In the experiment, a step current (with ∼2 μs rising time) is fed to the sample. The sample is heated and takes a certain
time to reach its steady thermal state. The temperature rising response of the sample is sensed by measuring the resistance
change of the thin Au coating. From the average temperature evolution of the sample, the thermal diffusivity can be extracted.
Three PAN wires with different diameters are synthesized using the electro-spinning technique and are measured to obtain their
thermal diffusivities (around 1.53×10-7 m2/s), which are slightly smaller than the bulk value.
PACS 65.80.+n; 66.30.Xj; 44.10.+i 相似文献
42.
讨论了一类具有双参数的椭圆型方程边值问题.引入伸长变量,构造了问题的形式渐近解.利用微分不等式理论,证明了边值问题渐近解的存在性和一致有效性.由解的结构指出,在两参数一定的情况下,相应问题的解只具有二个边界层. 相似文献
43.
44.
一类具有摄动边界的弱非线性反应扩散方程 总被引:1,自引:0,他引:1
研究了具有摄动边界的非线性反应扩散方程的问题.在适当的条件下,利用微分不等式理论,讨论了问题的渐近解. 相似文献
45.
Chao Hong Jiaqi Ma Meichao Li Liqun Jin Xinquan Hu Weimin Mo Baoxiang Hu Nan Sun Zhenlu Shen 《Tetrahedron》2017,73(21):3002-3009
A simple catalytic oxidation system was developed for the selective aerobic oxidation of structurally diverse benzylic sp3 CH bonds of ethers and alkylarenes. The reactions were performed with Fe(NO3)3·9H2O as the catalyst, KPF6 as the additive and molecular oxygen as the terminal oxidant without any ligands. Under the optimal reaction conditions, a number of isochromans, xanthenes and thioxanthenes can be converted to their corresponding esters or ketones in good to excellent yields. 相似文献
46.
Meili Qu Qiying Lv Bing Yang Weide Zhang Jiaqi Zhang Shuzhong Zhan Jianshan Ye 《Electroanalysis》2010,22(4):375-378
Supported bilayer lipid membrane (s‐BLM) containing one‐dimensional compound 1, TCNQ‐based (TCNQ=7,7,8,8‐tetracyanoquinodimethane) organometallic compound {(Cu2(μ‐Cl)(μ‐dppm)2)(μ2‐TCNQ)}∞, was prepared and characterized on the self‐assembled monolayer (SAM) of 1‐octadecylmercaptan (C18H37SH) deposited onto Au electrode. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results showed that the compound 1, dotted inside s‐BLM, can act as mediator for electron transfer across the membrane. Two redox peaks and the charge‐transfer resistance of 400 kΩ were observed for compound 1 inside s‐BLM. The mechanism of the electron transfer across s‐BLM by TCNQ is by electron hopping while TCNQ‐based organometallic compound is by conducting. Further conclusion drawn from this finding is that the TCNQ‐based organometallic compound embedded inside s‐BLM exhibits excellent electron transfer ability than that of free TCNQ. This opens a new path for the development of s‐BLM sensor and/or biosensor by incorporation with TCNQ‐based organometallic compounds. 相似文献
47.
介绍了金属有机物质热力学研究的进展,概述了过渡金属-配体键能的基本概念、估测方式、实验和理论研究方法.收集了已测得的第三副族到第八族所有中性金属有机络合物金属-配体σ-单键绝对键焓的实验值.对第三副族及锕系元素,收集了钪-氢、钪-碳、钍-氢、钍-碳、钍-氮、钍-氧、钍-硫、钍-氯、铀-氢、铀-碳、铀-硅、铀-氧、铀-氯、铀-溴、铀-碘、钐-氢、钐-碳、钐-硅、钐-氮、钐-磷、钐-氧、钐-硫、钐-氯、钐-溴和钐-碘键的键焓.对第四副族元素,收集了钛-碳、锆-氢、锆-碳、锆-硅、锆-氮、锆-氧、锆-氯、锆-碘、铪-氢、铪-碳键的键焓.对第五副族元素,收集了钒-氢、钽-碳键的键焓.对第六副族元素,收集了铬-氢、铬-碳、铬-硅、铬-氮、铬-氙、钼-氢、钼-碳、钼-硅、钼-氮、钼-磷、钼-氯、钼-溴、钼-碘、钼-氙、钨-氢、钨-碳、钨-硅、钨-氮、钨-氩、钨-氪、钨-氙键的键焓.对第七副族元素,收集了锰-氢、锰-碳、锰-硅、锰-氧、锰-硫、锰-氯、锰-溴、锰-碘、锝-氯、锝-溴、锝-碘、铼-氢、铼-碳、铼-氯、铼-溴、铼-碘键的键焓.对第八族元素,收集了铁-氢、铁-碳、铁-氮、铁-氩、铁-氪、铁-氙、钌-氢、钌-碳、钌-磷、锇-氢、锇-碳、钴-氢、钴-碳、铑-氢、铑-碳、铱-氢、铱-碳、铱-氯、铱-溴、铱-碘、镍-碳、镍-硫、钯-碳、铂-氢、铂-碳键的键焓.但未包括平均键焓值.此外,还收集了铁-氢、铁-碳、铁-氮、铁-磷、铁-羰基、铁-亚硝基、铁-氧分子、铁-硼、铁-铝、铁-镓、铁-铟、铁-铊键的理论计算值以及金属有机片断和离子的键焓. 相似文献
48.
49.
莫嘉琪 《高校应用数学学报(英文版)》2003,18(4):403-411
Recently the nonlinear singularly perturbed problem has been investigated in theinternational academic circles[1 ,2 ] .Approximation methods have been developed andrefined,including the method of averaging,boundary layer method,matched asymptoticexpanision method and multiple scales method.Many scholars such as O' Malley,Jr.[3] ,Butuzov,Nefedov and Schneider[4] ,Kelley[5] ,Mizoguchi,Yanagida and Life[6] have done agreat deal of work.Using the method of differential inequality and other met… 相似文献
50.
Mo Jiaqi Chen Xianfeng Xie Feng 《Annals of Differential Equations》2007,23(1):45-49
In this paper, the heat conductive problem with boundary perturbations is considered. Using the solvability of the problem, two eigenfunctions corresponding to two eigenvalues for the nm-th modular form are obtained. 相似文献