A moving screw dislocation near interfacial rigid lines in two dissimilar anisotropic media

This paper attempts to investigate the problem for the interaction between a uniformly moving screw dislocation and interface rigid lines in two dissimilar.anisotropic. materials. Integrating Riemann-Schwarz＇s symmetry principle with the analysis singularity of complex functions, we present the general elastic solutions of this problem and the closed form solutions for interfaces containing one and two rigid lines. The expressions of stress intensity factors, at the rigid line tips and image force acting on moving dislocation are derived explicitly. The results show that dislocation velocity has an antishielding effect on the rigid line tip and a larger dislocation velocity leads to the equilibrium position of dislocation closing with the rigid line. The presented solutions contain previously known results as the special cases.     

稀土有机光→电、电→光转换器件

198 6年Ｔａｎｇ发表双层有机光伏电池[1] 与无机光伏电池相比 ,以重量轻 ,材料经济并可以沉积在柔性衬底上等潜在优势正在引起人们注意。目前对有机光伏效应的研究多集中在聚苯乙炔 (ＰＰＶ)及其衍生物上[2 ,3 ] ,能量转换效率在 10ｍＷ·ｃｍ- 2 紫外光照下可超过 4 % [4 ] ;以小分子有机物制成的光伏器件也得到研究人员的关注[5,6] 。但是采用稀土配合物作为电子给体层的有机光伏器件还未见报道。我们研究组一直对以稀土有机配合物为发光层的有机ＥＬ器件进行研究[7,8] 。在研究ＥＬ器件特性过程中 ,我们发现稀土有机电致发光器件在紫外…     

辛基三乙氧基硅烷/十八烷基三氯硅烷均相混合自组装单分子膜的表征及其形成机制

使用接触角、原子力显微镜（AFM）、静电力显微镜（EFM）和傅里叶变换红外（FTIR）光谱对辛基三乙氧基硅烷（C8TES）/十八烷基三氯硅烷（OTS）均相混合自组装单分子膜（SAM）及其形成过程中样品表面的润湿性、表面形貌、表面电势和膜内分子的有序度进行了表征,对采用分步法利用C8TES分子空间位阻制备C8TES/OTS均相混合SAM的反应机制进行了研究. 结果表明,C8TES/OTS均相混合SAM表面接触角为105°,样品表面平整、光滑;对样品表面电势进行分析后发现,混合SAM表面电势分布均匀,电势频率分布为典型的正态分布;在均相混合SAM的形成过程中,样品表面电势的分布始终十分均匀,电势频率分布均为典型的正态分布;C8TES/OTS均相混合SAM是一种具有上下两层分子排列密度不同的膜结构的单分子膜,其内部结构至少在500 nm×500 nm到20 μm×20 μm尺度上是高度均匀一致的,膜内没有明显的特征结构,具有典型的均相混合SAM特征.     

生态材料学的内涵探讨

生态材料学是一门新不学科,本文探讨了其内涵,包括历史观,定义,判拓研究任务,理论基础,研究内容,生命周期评估,材料生命周期评估以及生态材料各论。     

交联苯乙烯/丙烯酰胺共聚微球的制备及其C60功能化初探

以二乙烯基苯（ＤＶＢ）为交联剂,利用一次科料分散共聚合的方法合成了交联的苯乙烯（Ｓｔ）／丙烯酰胺（Ａｍ）共聚微球。实验发现,共聚单体Ａｍ的投料量和介质的极性对微球的形态有着显著的影响。在反应过程中并联ＰＳ链段和ＰＡｍ链段发生相分离,使粒子产生异形。随后,通过微球上的酰胺基团与Ｃ６０的反应,将Ｃ６０引入微球表面。初步的光电导性能测试表明,带有Ｃ６０的微球具有较好的光电导性能。     

C60与甲基丙烯酸甲酯共聚物的制备及光电导性能的研究

通过自由基聚合的方法制备了一系列甲基丙烯酸甲酯和C₆₀的共聚物,实验结果表明,增加引发剂的含量可以大大提高共聚物的产率。用元素分析、GPC和DSC等方法对共聚物进行表征。首次尝试研究了不含导电高分子的C₆₀共聚物体系的光电导性能,结果表明,该类共聚物光电导性能良好。     

楔型向错偶极子和裂纹的干涉效应

研究了晶体材料中一个楔型向错偶极子与裂纹的弹性干涉效应．运用复变函数方法获得了复势函数和应力场的封闭形式解答,导出了裂纹尖端应力强度因子和作用在向错偶极子中心点像力的解析表达式．获得了向错偶极子的位置、方向和偶臂长度对裂纹尖端应力强度因子的影响规律,并讨论了裂纹附近向错偶极子的平衡位置．结果表明向错偶极子靠近裂纹尖端时,对应力强度因子有明显的屏蔽或反屏蔽作用．     

Shielding effect and emission criterion of a screw dislocation near an interfacial blunt crack

Shielding effect and emission criterion of a screw dislocation near an interfacial blunt crack are dealt with in this paper. Utilizing the conformal mapping technique, the closed-form solutions are derived for complex potentials and stress fields due to a screw dislocation located near the interfacial blunt crack. The stress intensity factor on the crack tips and the critical stress intensity factor for dislocation emission are also calculated. The influence of the orientation of the dislocation and the morphology of the blunt crack as well as the material elastic dissimilarity on the shielding effect and the emission criterion is discussed in detail. The results show that positive screw dislocations can reduce the stress intensity factor of the interfacial blunt crack tip (shielding effect). The shielding effect increases with the increase of the shear modulus of the lower half-plane, but it decreases with the increase of the dislocation azimuth angle. The critical loads at infinity for dislocation emission increases with the increase of emission angle and curvature radius of blunt crack tip, and the most probable angle for screw dislocation emission is zero. The present solutions contain previous results as special cases.     

应用FTIR直接测定法鉴定大豆的品种

利用傅里叶变换红外光谱(FTIR)法测定了8个不同大豆品种的子叶及外表皮的红外光谱,对他们的红外光谱进行了分析,并对其吸收峰进行了归属。通过对各谱图的比较分析发现,不同的大豆品种的红外吸收峰形及峰强有所区别。结果表明： 不同的大豆品种的FTIR有明显的差别,特别是1 800～1 200 cm-1范围内有较大的差异,它反映的主要是蛋白质分子的酰胺Ⅰ带及酰胺Ⅱ带附近,这可能是源于基因的差异。因此FTIR法可用于不同大豆品种的鉴别。     

Antiplane problem of circular ARC interfacial rigid line inclusions

The antiplane problem of circular arc rigid line inclusions under antiplane concentrated force and longitudinal shear loading was dealt with. By using RiemannSchwaz‘s symmetry principle integrated with the singularity analysis of complex functions, the general solution of the problem and the closed form solutions for some important practical problems were presented. The stress distribution in the immediate vicinity of circular arc rigid line end was examined in detail. The results show that the singular stress fields near the rigid inclusion tip possess a square-root singularity similar to that for the corresponding crack problem under antiplane shear loading, but no oscillatory character. Furthermore, the stresses are found to depend on geometrical dimension, loading conditions and materials parameters. Some practical results concluded are in agreement with the previous solutions.