不同热处理条件下Cu-Zn-Sn合金显微组织研究

文章主要研究了Ｃｕ－Ｚｎ－Ｓｎ合金系列在不同的热处理条件下得到的金相组织形貌。通过选用不同成分配比的试样、不同的加热温度和不同的淬火介质,研究了马氏体形貌的变化,并初步分析了产生不同形貌马氏体的原因和机理     

大气环境腐蚀性因素的相关性

通过相关性数据处理和模糊聚类分析,发现影响大气环境腐蚀性的２１种环境因素在相关系数大于０．５４的情况下,可明显地聚为５类．在此基础上,进一步通过对逐个因素的分类能力的特征评价,选取大气环境腐蚀性的主要因素（ＲＨ＞８０％时数,Ｓ０２沉积速度,水溶性尘降,Ｃｌ－沉积速度,ＮＯ２浓度）,进而在特征空间中进行镀锌层样本的大气环境腐蚀性预测和考评,为今后实现我国大气环境腐蚀性等级评判提供依据．     

Ca2+ signals induced from calcium stores in pancreatic islet β cells

In single rat pancreatic β cells, using fura-2 microfluorometry to measure [Ca²⁺]i response upon different stimuli, the ways of calcium regulation have been studied. When the extracellular calcium concentration was 2.5 mmol/L, either 60 mmol/L KCl, 20 mmol/L D-glucose or 0.1 mmol/L tolbutamide induced increase in [Ca²⁺]i. Such increase in [Ca²⁺]i was absent when the same stimuli were applied under zero extracellular calcium. These results indicate that the increase of [Ca²⁺]i is induced by the activation of voltage-dependent calcium channels in β cells. The manifold forms of [Ca²⁺]i change induced by glucose imply that the effects of glucose are complex. 5 mmol/L caffeine or 5 mmol/L MCh increase the [Ca²⁺]i, which is independent of the external calcium, suggesting that [Ca²⁺]i can be regulated by Ca²⁺ release from not only the IP₃-sensitive but also the ryanodine sensitive calcium stores in β cells. The latency of Ca responses for IP₃ pathway (5 s) is faster than that for ryanodine pathway (30 s). It is concluded that there are multiple calcium stores in rat pancreatic β cells.     

An anther-specific chalcone synthase-like geneD5 related to rice pollen development

It was shown in a previous analysis that D5 gene from rice (Oryza sativa L.) was an anther-specific gene encoding a chalcone synthase-related protein. In this study, D5 gene was found specifically expressed in tapetum cells as well as in the peripheral cells of the vascular bundle of rice anthers by RNA in situ hybridization. In order to study its function, D5 was transformed into rice in both sense and antisense directions driven by a rice Actin 1 promoter. It has been observed that the pollen grains from the antisense D5 transgenic rice plants are abnormal, indicating that D5 plays a critical role in rice pollen development.     

基于进化规划的OCST问题求解

提出基于进化规划求解ＯＣＳＴＰ（ＯｐｔｉｍａｌＣｏｍｍｕｎｉｃａｔｉｏｎＳｐａｎｎｉｎｇＴｒｅｅＰｒｏｂｌｅｍ）的新方法。通过对原有启发式算法和遗传算法的分析,指出原有方法的不足和难点,并对进化规划算法应用于该问题的可行性进行了分析,最后给出了仿真结果和分析     

应用多属性决策的威胁评估方法

威胁评估是作战系统需要完成的功能之一 ,对实现指挥控制系统自动化是非常重要的。威胁评估涉及的因素比较多 ,目前还没有统一的方法。威胁评估实际上是一个推理、决策的行为 ,而决策理论为推理、决策提供了理论方法。根据威胁评估和多属性决策的特点 ,提出了基于多属性决策的威胁评估模型和方法 ,应用隶属函数及逼近于理想的排序法 (TOPSIS)分析 ,并通过示例说明应用多属性决策的威胁评估方法。     

Protoporphyrin Ⅸ and verteporfin potently inhibit SARS-CoV-2 infection in vitro and in a mouse model expressing human ACE2

The SARS-CoV-2 infection is spreading rapidly worldwide.Efficacious antiviral therapeutics against SARS-CoV-2 is urgently needed.Here,we discovered that protopo...     

磁流变阻尼器的磁滞效应与神经网络预测调整

研究了磁流变阻尼器的磁滞效应对控制效果的影响,提出了采用神经网络预测的方法来减小磁滞效应对振动控制的不利影响.通过过去时刻和当前时刻的结构响应来预测将来时刻的结构响应,并用线性最优控制(LQR)算法经将来时刻结构响应计算得到主动控制力,为磁流变阻尼器产生该主动控制力赢得时间.研究结果表明:通过神经网络预测能有效补偿磁滞时间,使控制效果接近无磁滞效应的控制效果.     

基于空间活跃度网络的搜索策略研究

基于具有时变特性与空间特性的空间活跃度网络模型,研究了时变网络中的搜索问题。结合空间活跃度网络的特性,引入了搜索时间、搜索路径长度和等待时间3种搜索策略的评价指标,提出了最大活跃度搜索策略、改进的贪婪搜索策略和最大活跃度最小距离搜索策略。利用这些策略在空间活跃度网络中进行搜索,研究发现和其他的搜索策略相比,改进的贪婪搜索策略与最大活跃度最小距离搜索策略具有较好的搜索性能,能够很好地适用于这种类型的时变网络,从而优化了目标搜索的过程。