张量方程AX+XA=C求解的几种途径

利用Rivlin恒等式给出了张量方程AX+XA=C七种不同的表示形式,此方法与已有的方法相比,不但方法简单,并且还获得了几种新的表示形式.     

高孔隙率多孔介质材料有效复合模量的预估

利用分割孔隙的方法,取一半孔隙作为夹杂,另一半和原基体作为新基体,首先利用Mori-Tanaka法求得新基体的有效模量,然后类似地对新基体和另一半孔隙,利用相同的方法求得多孔介质的有效复合模量。通过实例计算表明,即使当孔隙率较大时,现方法与试验数据也相当吻合。     

Predicting the spread of nuclear radiation from the damaged Fukushima Nuclear Power Plant

Japan suffered a M9.0 earthquake and massive tsunami on March 11, 2011, which seriously damaged the Fukushima Nuclear Power Plant and caused a nuclear crisis. The spread of nuclear radiation from the power plant through the atmosphere and ocean was predicted with a short-term climate forecasting model and an ocean circulation model under some idealized assumptions. If nuclear matter were leaked in the near-ground layer of 992 hPa, the climate model results show that the nuclear radiation would cover North America 10 days after the initial leakage, with the concentration at the forefront dramatically reduced to 10 millionths of the initial model concentration at the source. The radiation would span Europe in 15 days and cover much of the Northern Hemisphere in 30 days. If the initial leakage was assumed to occur in the layer 5000-m above the ground, the radiation would cover Europe in 10 days and cover much of the Northern Hemisphere in 15 days. Moreover, under the assumption that the nuclear matter leaked in the 10000-m layer, the radiation would affect much of China after 10 days. The ocean circulation model indicates that the nuclear material would be slowly transported northeast of Fukushima and reach 150°E in 50 days, and the nuclear debris in the ocean would be confined to a narrow band. Compared with the spread in the ocean, the area affected by leaked nuclear radiation in the atmosphere would be very large. Atmospheric monitors in North America and Europe will be helpful for estimating the effect in China of any leaked nuclear material.     

回火温度对40Cr钢疲劳损伤特性的影响

研究了不同回火温度下40Cr钢的高周疲劳损伤特性.通过损伤量的变化测量和扫描电镜下损伤不同阶段微观组织的观察,分析回火温度对疲劳损伤特性的影响.实验结果表明,结构钢材料在高周疲劳载荷作用下,疲劳损伤过程分为3个阶段,即微孔洞萌生区、微裂纹萌生区、宏观裂纹萌生区.疲劳裂纹的萌生期随着回火温度的升高而增加,在本实验的载荷作用下,高温回火的40Cr钢的裂纹萌生期在3万周以上,中温回火的裂纹萌生在2.8万周,而低温回火的裂纹萌生期在2万周.     

A note on the derivation of the derivatives of invariants of stretch tensor to the right Cauchy-Green tensor

A new approach for the derivation of the principal invariants of the stretch tensor with respect to the right Cauchy-Green tensor is presented in this paper. According to the definition of the derivation of tensor function, the three first-order derivatives for the principal invariants of the stretch tensor are obtained through derivation directly to the right Cauchy-Green tensor by incremental method. Then the three second-order derivatives are yielded by the derivation to the right Cauchy-Green strain tensor directly. Furthermore, an explicit expression of the tangent modulus of the general Varga material is given as an example.     

Drift characteristics of green macroalgae in the Yellow Sea in 2008 and 2010

In order to investigate the aggregation mechanism of green macroalgae (Enteromorpha prolifera) on the Qingdao coastline, the macroalgal drift characteristics in the Yellow Sea during June and July in 2008 and 2010 were simulated using a three-dimensional wave-tide-circulation coupled model. In June 2008, the monthly-mean surface current flowed onshore and its direction was almost perpendicular to the Qingdao coastline, which was identified as the main reason for a huge accumulation of algae in the coastal waters off Qingdao. The current became parallel to the coastline in July 2008; this shift in current direction led to little accumulation of algae near Qingdao and thus relieved the environmental pressure on the Olympic sailing events. By using the coupled model, we predicted that there would be no serious algal accumulation at Qingdao in late June 2010, which was later confirmed by observations. This study demonstrated that the drift path of macroalgae near Qingdao is mainly controlled by the surface current, which is primarily driven by wind. Regional climate change is therefore one of the means by which physical processes affect marine ecosystems.     

可能世界叙事学理论模型与《宠儿》的叙事特征

本文借用张新军的可能世界叙事学理论模型,分析了托尼莫里森的小说《宠儿》的叙事特征。《宠儿》以真实故事为基础,是对现实世界(玛格丽特弑女事件)之外的可能世界(包括故事发生的时间、地点,与女主人公相关人物和奴隶制造成的生理和心理创伤)的描绘。作者用优美的语言和精妙的叙事方法设置了一系列谜团,为读者解开了故事谜团,同时留下了一些未解之谜。别具匠心的人称使用和情节发展进一步彰显了作者娴熟的叙事风格。     

关于3种计算张量函数方法的比较

对计算各向同性对称张量函数的3种方法(谱分解法、特征投影算子法和表示定理法)进行了分析比较,同时也对如何计算特征根与特征向量的技巧进行了探讨,并利用3种方法对指数张量函数进行了实例计算.结果表明,表示定理法所用的时间最短,谱分解法次之,为编制计算程序时如何选择计算张量函数的方法提供参考.     

对数应变张量的近似计算公式

基于泰勒展开给出对数应变张量的级数表示,利用选取不同的项数和不同的展开点,得到对数应变张量的误差最小近似表达式.结合简单实例,对近似计算结果的精度和计算时间与精确解进行比较.结果表明,获得的对数应变张量近似表达式不但简单,而且计算时间短、精度高、适用范围也相当广泛.     

Micromechanical analysis of interaction energy for SMA reinforced composite

The energy of the interaction between the matrix and the inclusions in shape memory alloy (SMA) reinforced composite is one of the most important and complicated parts in thermodynamic constitutive theory.In this paper,the interaction energy is derived based on the classical theory of micromechanics and the thermodynamic theory.The SMA composite is treated as three phases,namely the austenitic phase,the martensite phase and the matrix phase.The interaction among the three phases is analyzed in a way close t...