极端温差对超长高层建筑的影响

探讨了极端温差对超长高层建筑结构的影响问题。通过历史统计数据设计了作用在超长高层建筑结构上的极端温差工况 ,以典型超长高层建筑实际工程为例 ,采用有限元方法 ,建立了接近工程原型的有限元模型 ,计算得出该建筑整体结构和各种构件的温度效应 ,从中总结出温度变形、温度内力或应力的大小范围及分布规律 ,计算结果可为工程技术人员在设计和施工中考虑极端温度效应提供依据。     

Elastic,mechanical, electronic,and defective properties of Zr–Al–C nanolaminates from first principles

By means of first principles calculations, Zr–Al–C nanolaminates have been studied in the aspects of chemical bonding, elastic properties, mechanical properties, electronic structures, and vacancy stabilities. Although the investigated Zr–Al–C nanolaminates show crystallographic similarities, their predicated properties are very different. For (ZrC)_nAl₃C₂ (n = 2, 3, 4), the Zr–C bond adjacent to the Al–C slab with the C atom intercalated in the Zr layers is the strongest, but the one with the C atom intercalated between the Zr layer and Al layer is the weakest. In contrast, the situation for (ZrC)_nAl₄C₃ (n = 2, 3) is just the opposite. For Zr–Al–C nanolaminates, the calculated bulk, shear and Young's modulus increase in the sequence of Zr₂AlC < Zr₃AlC₂ < Zr₂Al₄C₅ < Zr₃Al₄C₆ < Zr₂Al₃C₄ < Zr₃Al₃C₅ < Zr₄Al₃C₆. The (ZrC)_nAl₃C₂ (n = 2, 3, 4) series exhibit the most outstanding elastic properties. In the presence of the external pressure, the bulk and shear moduli exhibit a linear response to the pressure, except for Zr₂AlC and Zr₃AlC₂, both of which belong to the so‐called MAX phases. The two materials also exhibit very distinct properties in the strain‐stress relationship, electronic structures and vacancy stabilities. As the intercalated Al layers increase, the formation energy of V_Zr and V_Al increases, while the formation energy of V_C decreases.     

网络威胁情报关联分析技术

在巨大的利益诱惑下,网络攻击技术正在快速畸形发展,与此同时网络防御技术却显得捉襟见肘,缺乏有效的技术手段和理论依据对网络威胁事件进行追踪溯源.针对攻击数据碎片化、溯源线索难提取、攻击链条难关联等问题,分析网络威胁情报的特点,设计网络安全知识图谱,包括6类网络威胁情报实体、14种实体关系,以构建的知识图谱为基础,提出5种...     

数字化汽车传感器的研究

为了将汽车模拟传感器输出的信号转换为数字信号,采用了V/F转换器与M C U接口的方法,并通过I2C总线协议,对传感器数据进行传输.试验表明,本文所述的传感器数字化方法可行,适应在汽车控制系统中应用.     

大坝安全监控知识库系统研究

探讨了大坝安全监控知识库系统的设计、知识表示方法的研究、知识获取模型的建立、知识推理的实现以及应用关系数据库技术实现对大坝安全监控知识的管理等问题。     

一种室内采光模糊控制器的研究

针对室内采光要求,对于室内含有百叶遮阳帘和照明补光的系统,本文提出了一种基于二维纯模糊控制算法的计算机室内采光控制系统。介绍了该系统的控制原理、模糊变量、隶属度函数以及控制规则表的确定,也给出了控制算法的程序模块。该系统采用查询模糊规则表的方式,通过硬件接口电路有效地控制遮阳百叶的遮阳角度,并在特定条件下进行室内照明的智能补光控制。在满足视觉舒适度的同时节约了室内照明用电。     

测井电缆缆芯复用器的设计与实现

文章根据过套管地层电阻率测井技术对测井信息传输系统的要求，运用复用技术即采用DSP程序控制继电器动作的方案设计了一款缆芯复用器，实现了对测井电缆缆芯功能转换的控制，同时使用光电隔离电路避免控制信号间的干扰，从而有效地解决了测井电缆缆芯数目有限的问题。     

Interface fracture behavior of electroplated coating on metal substrate under compressive strain

The inducement of interface fracture is crucial to the analysis of interfacial adhesion between coating and substrate. For electroplated coating/metal substrate adhering materials with strong adhesion, interface cracking and coating spalling are difficult to be induced by conventional methods. In this paper an improved bending test named as T-bend test was conducted on a model coating system, i.e. electroplated chromium on a steel substrate. After the test, cross-sections of the coated materials were prepared to compare the failure behaviors under tensile strain and compressive strain induced by T-bend test. And the observation results show that coating cracking, interface cracking and partial spalling appear step by step. Based on experimental results, a new method may be proposed to rank the coated materials with strong interfacial adhesion.     

多专家联合求解系统中不确定性处理

在多个专家联合求解的系统中,有时每个专家给出了多个不同的结论和可信度值,有时给出同一个结论和不同的可信度值。为处理这种不确定性,本文提出了模糊综合评判的方法来处理第一种不确定性;对第二种不确定性的处理采用平均值、加减法和影响法来调整各可信度值,最后用加权平均和模糊熵方法来求出一个统一的可信度值。     

具有宽波反射特性的手征向列相液晶的研究进展

简要说明了手征向列相液晶的形成方式、分子排列特点和光学性质,详细介绍了具有宽波反射特性的手征向列相液晶在国内外的研究进展情况,概括了特殊的多螺距分布结构的形成机理,并展望了其应用前景及发展方向.