FEM for evaluation of weight functions for SIF, COD and higher-order coefficients with application to a typical wedge splitting specimen

In the evaluation of accurate weight functions for the coefficients of first few terms of the linear elastic crack tip fields and the crack opening displacement (COD) using the finite element method (FEM), singularities at the crack tip and the loading point need to be properly considered. The crack tip singularity can be well captured by a hybrid crack element (HCE), which directly predicts accurate coefficients of first few terms of the linear elastic crack tip fields. A penalty function technique is introduced to handle the point load. With the use of these methods numerical results of a typical wedge splitting (WS) specimen subjected to wedge forces at arbitrary locations on the crack faces are obtained. With the help of appropriate interpolation techniques, these results can be used as weight functions. The range of validity of the so-called Paris equation, which is widely used in the evaluation of the COD from the stress intensity factors (SIFs), is established.     

落锤试验测定船板的无塑性转变温度

无塑性转变温度是安全设计的重要参量，广泛应用于材料研究和产品质量控制过程。利用落锤试验方法，测定了AH36级船板的无塑性转变温度为-25℃，并对试验结果进行了评定。结果表明，落锤试验方法简单，试验数据重复性好，当船板的服役温度高于NDTT时，基本保证船板不会发生脆断。     

基于相关性反馈的自适应热点话题追踪模型

针对在热点话题追踪过程中容易发生话题漂移的问题,提出了基于相关性反馈的自适应热点话题追踪模型。为准确把握话题的动态演变过程,首先,在词频-逆向文档频率(term frequency-inverse document frequency, TF-IDF)的基础上引入了相关度因子。其次,构造了报道与话题的相关度计算公式和新特征词能否反馈加入到话题词汇库的判别函数。同时,利用了话题词汇库本身的特性,构造了自适应更新阈值和自适应相关阈值的动态计算方法。最后,根据各个特征词对该话题贡献度的大小,对更新后的词汇库中的各特征词动态赋予新权重。实验结果显示,和其它3类追踪器相比,该追踪器模型的漏报率平均降低0.018、误报率平均降低0.063,这表明,该追踪模型更适合于解决话题漂移问题。     

高聚物中渗入C_(60)/C_(70)后计算内阻的压力函数法

应用宏观力学模型对高聚物渗入Ｃ６０／Ｃ７０后的微观内阻机理进行力学分析,提出分子滚珠轴承的设想,得出计算内阻的压力函数法和滚滑内阻权函数的概念。     

电子衡器在中铝广西分公司矿山生产中的应用

电子衡器目前在国内工业企业中得到了广泛使用,文章从其原理出发,结合电子衡器在中国铝业广西分公司矿山部实际运行状况,阐述了该称重设备的使用与维护要领。     

Hierarchical Spatially Varying Coefficient Process Model

The spatially varying coefficient process model is a nonstationary approach to explaining spatial heterogen-eity by allowing coefficients to vary across space. In this article, we develop a methodology for generalizing this model to accommodate geographically hierarchical data. This article considers two-level hierarchical structures and allow for the coefficients of both low-level and high-level units to vary over space. We assume that the spatially varying low-level coefficients follow the multivariate Gaussian process, and the spatially varying high-level coefficients follow the multivariate simultaneous autoregressive model that we develop by extending the standard simultaneous autoregressive model to incorporate multivariate data. We apply the proposed model to transaction data of houses sold in 2014 in a part of the city of Los Angeles. The results show that the proposed model predicts housing prices and fits the data effectively.     

UST-4条干仪的测试及应用

文章介绍了乌斯特条干仪的条干、毛羽测试原理及条干测试数据指标的涵义,阐述了如何应用这些测试图形和数据结果对纱线质量进行分析和应用.通过数据和图形可以直观地看出纱线的品质,通过波谱图可以查找到产生疵病的工艺部件,并对其进行检修,为纺纱提供了较好的条干检测和应用方法,以寻找各道纺纱工序的最佳工艺条件.     

求解无等待流水调度的基于禁忌搜索的混合算法

本文提出了解决最小完工时间的无等待流水调度问题的基于禁忌搜索的混合算法。算法结合了调度规则和禁忌搜索算法的优点,首先利用调度规则构造较好的初始解,既可以加快禁忌搜索算法的收敛速度,也可以降低整个算法的运算量,使算法有更好的工程实用性;然后使用变邻域结构的禁忌搜索算法改进当前解。在保持可达性的基础上,该算法缩小了邻域规模和减少了计算时间。数值仿真实验表明,该算法是有效的。     

ILB®, a Low Molecular Weight Dextran Sulphate,Restores Glutamate Homeostasis,Amino Acid Metabolism and Neurocognitive Functions in a Rat Model of Severe Traumatic Brain Injury

In a previous study, we found that administration of ILB^®, a new low molecular weight dextran sulphate, significantly improved mitochondrial functions and energy metabolism, as well as decreased oxidative/nitrosative stress, of brain tissue of rats exposed to severe traumatic brain injury (sTBI), induced by the closed-head weight-drop model of diffused TBI. Using aliquots of deproteinized brain tissue of the same animals of this former study, we here determined the concentrations of 24 amino acids of control rats, untreated sTBI rats (sacrificed at 2 and 7 days post-injury) and sTBI rats receiving a subcutaneous ILB^® administration (at the dose levels of 1, 5 and 15 mg/kg b.w.) 30 min post-impact (sacrificed at 2 and 7 days post-injury). Additionally, in a different set of experiments, new groups of control rats, untreated sTBI rats and ILB^®-treated rats (administered 30 min after sTBI at the dose levels of 1 or 5 mg/kg b.w.) were studied for their neurocognitive functions (anxiety, locomotor capacities, short- and long-term memory) at 7 days after the induction of sTBI. Compared to untreated sTBI animals, ILB^® significantly decreased whole brain glutamate (normalizing the glutamate/glutamine ratio), glycine, serine and γ-aminobutyric acid. Furthermore, ILB^® administration restored arginine metabolism (preventing nitrosative stress), levels of amino acids involved in methylation reactions (methionine, L-cystathionine, S-adenosylhomocysteine), and N-acetylaspartate homeostasis. The macroscopic evidences of the beneficial effects on brain metabolism induced by ILB^® were the relevant improvement in neurocognitive functions of the group of animals treated with ILB^® 5 mg/kg b.w., compared to the marked cognitive decline measured in untreated sTBI animals. These results demonstrate that ILB^® administration 30 min after sTBI prevents glutamate excitotoxicity and normalizes levels of amino acids involved in crucial brain metabolic functions. The ameliorations of amino acid metabolism, mitochondrial functions and energy metabolism in ILB^®-treated rats exposed to sTBI produced significant improvement in neurocognitive functions, reinforcing the concept that ILB^® is a new effective therapeutic tool for the treatment of sTBI, worth being tested in the clinical setting.     

基于RGBD数据与深度权重的压缩光场显示

使用多层空间光调制器的压缩光场(compressive light field,CLF) 显示技术具有空间带宽利用率高、图像分辨率好等优势,是一种很有前景的光场显示技术。传统的方法将光场分解视为超定问题并使用优化算法求解。随着重建光场的分辨率、深度、视角等性能参数的提升,优化算法的计算效率低、内存消耗大的缺陷被放大,难以实现快速计算。为此,本文提出了一种新型CLF分解算法,该算法将原始光场分解为物点进行存储,仅占用少量内存;利用深度权重和加权平均代替了优化算法,大幅提高了运算效率。在同等条件下,所提出的算法占用内存仅是传统方法的38.8%,计算时间缩短了93.7%,图像质量提高约1 dB。最后通过仿真和实验两种方式对比了该方法和传统方法的显示效果,验证了算法的有效性。