基于稳态电热拉曼技术的碳纳米管纤维导热系数测量及传热研究

利用稳态电热拉曼技术测量了碳纳米管纤维对流换热环境下的导热系数. 该方法基于材料拉曼信号与温度之间的关系, 实时探测一维材料在不同电加热(内热源)下的中心点温度, 利用对流环境下的稳态导热模型推导出材料的导热系数, 实现了一维微纳材料热物性的无损化和非接触式测量. 实验发现: 碳纳米管纤维的导热系数远低于单根碳纳米管的导热系数, 但高于碳纳米管堆积床的导热系数. 这表明碳纳米管体材料的热物性主要取决于内部管束的列阵和管束间的接触热阻.     

CONSTANT ELASTICITY OF VARIANCE MODEL AND ANALYTICAL STRATEGIES FOR ANNUITY CONTRACTS

The constant elasticity of variance（CEV） model was constructed to study a defined contribution pension plan where benefits were paid by annuity. It also presents the process that the Legendre transform and dual theory can be applied to find an optimal investment policy during a participant＇s whole life in the pension plan. Finally, two explicit solutions to exponential utility function in the two different periods （before and after retirement） are revealed. Hence, the optimal investment strategies in the two periods are obtained.     

基于结构元方法的巷道煤体破碎程度综合评判

针对煤巷掘进或采煤生产过程中,煤体的破碎程度直接影响着巷道的支护方式和采煤工艺.利用结构元方法给出模糊综合评判的结构元表达形式,在此基础上,根据煤层地质构造、煤的硬度、压力参数、采煤方法等因素.对巷道煤体破碎程度进行综合评判.进而较为客观地评价出其破碎类别,从而为巷道支护方案和生产措施的选择提供依据.     

蕴含权重的偏序集多准则决策法

针对偏序集方法不能解决含有权重的多准则决策问题,提出一种“隐式”赋权的偏序决策方法。首先将含有m个方案和n个准则的决策问题表示成偏序集,之后按权重由大到小的顺序,对准则进行逐步相加形成n个新的准则,得到一个新的偏序集。根据偏序集间的包含关系,证明了新偏序集不仅蕴含了权重信息,而且比初始偏序集有更强的排序能力。结果表明,该法在应用中仅需获取权重排序信息,无需精确权重,适用于权重难以确定的多准则决策问题。以三峡库区水质评价为例,例子表明新方法明显优于原有的偏序决策方法,能够对13个方案进行聚类和排序,而原有方法在该例中几乎难以应用。     

渗透壓法測定高聚物的分子量

一.引言 滲透壓在溶液的經典理論中,佔有重要的地位,但是對低分子溶液,很難找到理想的半透膜,這實驗上的困難,就沒有使渗透壓作為一個驗證溶液理論的有效工具。對高分子溶液,情形就完全不同,由於溶質與溶劑分子大小的懸殊,半透膜的選擇比較容易,滲透壓的测定已被廣泛使用來测定高聚物的分子量並用來研究溶液中高分子與溶劑分子間的相互作用。     

由4',4'-二羟基-2-甲酸－三苯基甲烷及其衍生物制备高碳超支化芳香聚酯

合成了一系列含羟基和乙酰氧基的超支化聚酯，将4',4'二羟基-2-甲酸－三 苯基甲烷（酚酞啉）直接缩聚和将4~＇,4~＂-二羟基-2-甲酸－三苯基甲烷进行酯 交换反应都成功得到了超支化聚酯，以PS作标准物，由GPC测得的重均分子量为 2000到8000，~13C NMR测试表明聚合物支化度略高于50%，聚酯的玻璃化转变温度 依赖于末端和侧基官能团类型，该超支化聚酯末端含有反应性官能团，具有类似线 性高分子的高的热稳定性，相比之下，由于其大分子的形状和官能团的影响，末端 为乙酰氧基的超支化聚枉费显示了优良的溶解性能，这与一般线性高分子大不相同 ，由于氢键的存在，末端为羟基的超支化聚酯的溶解性能不佳，但是酸酯显示了 优良的溶解性能，这与一般线性高分子大不相同，由于氢键的存在，末端为羟基的 超支化聚枉费的溶解性能不佳，但是酸化可破坏氢键网络，得到的超支化聚酯可深 于一般有机溶剂。     

Sterols from the Fungus Catathelasma imperiale

Eight ergostane-type sterols and three their derivatives (one mono-linoleate and two mono-glucosides) were isolated from the ethyl acetate soluble fraction of the fungus Catathelasma imperi.a/e. Two of them are novel compounds, namely 22E,24R-er-gosta-7,22-diene-3β ,5α-diol-6β-linoleate (1) and 22E, 24R-er-gosta-7,22-diene-3β, 5β, 6α-triol (5) with an uncommon c/s-fused A/B ring. Structures of these compounds were demon-strated on the basis of their chemical evidences and spectroscop-ic methods, especially 2D NMR techniques.     

交叉共轭型烯酮化合物分子内的电荷转移

近年来有关分子内电行转移化合物的设计、合成及其光谱、光物理并为的研究引起＾们极大的兴趣[1－4]．这类化合物在激发态时常表现出一些特殊的性能，如出现扭曲的分子内电行转移（TICT）现象，并在荧光光谱中出现奇特的K重发光和在荧光强度与温度的依赖关系上出现反常等[5]．TICT态的形成强烈的依赖于化合物分子本身的结构，屯依赖于化合物分子所处环境的极性、温度和粘度等因素同．带有强给电子基（CH3卜N烁酮类化合物是一类有效的光敏剂．它广泛的应用于如光引发聚合、全息成像[7-8]等不同领域．同时其光谱及光物理行为的研究也已兑…     

2005年高考数学全国卷(Ⅱ)评析

2005年高考,吉林、黑龙江和广西等省共用全国卷Ⅱ,试题贯彻了&;lt;考试大纲&;gt;确定的高考命题的指导思想和原则,在平和的氛围中透出清新,在稳定的前提下追求创新,达到了考基础、考能力、考素质、考潜能的考试目标.……     

THE ANALYSES OF THE THREE-DIMENSIONAL STRESS STRUCTURE NEAR THE CRACK TIP OF MODE I CT SPECIMENS IN ELASTICPLASTIC STATE(II)—THE ANALYSES OF THE STRESS STRUCTURE

Based on [1], the stress structures of the smooth region and shear lip of the specimens have been investigated in the paper. The characteristics of the stress structure in the smooth region have been found that the variable z can separated out; the stresses in the midsection can be obtained by the plane strain FEM results or HRR structure modified by the stress triaxiality. The effects of load level and thickness on the stress structure can be reflected by the distribution of CTOD along the thickness direction. The obtained expressions of the stresses are very simple and visualized. The analyses of the stress structure in the shear lip show that the stresses can be obtained by different methods of interpolation to a certain precise degree. A new degree parameter of the plane strain state has been put forward and studied. The parameter can reflect relatively well the variation of the kind and thickness of the specimen as well as the load level. The fracture parameter has also been investigated to be sure that it can be obtained by modified CTOD with the stress triaxiality.