附加载荷作用下螺栓法兰连接的强度和紧密性分析

运用三维有限元方法模拟了垫片的非线性特性,分析了附加载荷对螺栓法兰连接结构的强度和紧密性的影响,确定了连接系统的紧密性、附加载荷和垫片残余压紧应力三者之间的关系。分析结果表明,附加弯矩对螺栓法兰连接结构的紧密性有较大影响。     

周调节贯流式水电站主汛期汛限水位动态控制

洪江电厂建成时采用国内单机容量最大、水头最高的灯泡贯流式机组,适应水头变化范围8.4～27.3 m,水库设计为周调节.通过分析洪江周调节方式的贯流式水电站汛限水位动态控制的必要性和可行性,研究汛限水位动态控制过程,拟定了汛限水位动态控制的具体实施方案,对提高水能利用率,确保防洪度汛安全具有重要意义.     

基于ESO-UKF的动力电池内部温度在线估计

准确的内部温度估计对动力电池的安全使用至关重要,为了在线获取准确的电池内部温度,本文提出一种基于温度估计模型的ESO-UKF电池内部温度估计方法。其中温度估计模型由Bernardi生热模型与热路传热模型组成,生热模型中端电压由神经网络获取,传热模型参数由递推最小二乘法辨识得到;该算法利用温度估计模型的离散状态空间描述,提出ESO-UKF进行电池内部温度的在线估计,将影响估计精度的传感器偏差视为扩展状态与原状态一起估计,实现了对不确定状态的估计;测试验证表明该算法的估计误差小于1℃,能够实现多工况下内部温度的在线估计,估计精度高、适应性强。     

QoRank: A query‐dependent ranking model using LSE‐based weighted multiple hyperplanes aggregation for information retrieval

Ranking is a core problem for information retrieval since the performance of the search system is directly impacted by the accuracy of ranking results. Ranking model construction has been the focus of both the fields of information retrieval and machine learning, and learning to rank in particular has attracted much interest. Many ranking models have been proposed, for example, RankSVM is a state‐of‐the‐art method for learning to rank and has been empirically demonstrated to be effective. However, most of the proposed methods do not consider about the significant differences between queries, only resort to a single function in ranking. In this paper, we present a novel ranking model named QoRank, which performs the learning task dependent on queries. We also propose a LSE (least‐squares estimation) ‐based weighted method to aggregate the ranking lists produced by base decision functions as the final ranking. Comparison of QoRank with other ranking techniques is conducted, and several evaluation criteria are employed to evaluate its performance. Experimental results on the LETOR OHSUMED data set show that QoRank strikes a good balance of accuracy and complexity, and outperforms the baseline methods. © 2010 Wiley Periodicals, Inc.     

基于Rough集潜在语义索引的Web文档分类

Rough集(粗糙集)埋论是一种处理不确定或模糊知识的数学工具。提出了一种基于Rough集理论的潜在语义索引的Web文档分类方法。首先应用向量空间模型表示Web文档信息，然后通过矩阵的奇异值分解来进行信息过滤和潜在语义索引；运用属性约简算法生成分类规则，最后利用多知识库进行文档分类。通过试验比较，该方法具有较好的分类效果。     

消息联盟系统中保持消息因果序协议的研究

由多个代理服务器组成的消息中间件联盟系统提供了更好的扩展性，但没有保证消息之间的因果序关系。该文提出并设计了一个新的保证消息因果序的通信协议MOMCO，该协议基于向量时钟，不但保证在消息联盟系统中消息的因果序，而且携带的排序控制信息量小，避免了采用二维矩阵时钟导致的较高代价，适用于大规模应用的场合。     

缠绕式垫片分级设计制造理论和技术

通过不同材料、不同结构的组合以及制造工艺参数的合理选择,可制成不同性能的缠绕式垫片以适应不同介质、不同工况的使用要求。提出了缠绕式垫片分级设计与制造的概念,建立了基于垫片结构参数和生产工艺参数优化以及螺柱凸缘联接紧密性分析方法的分级设计制造理论,探讨了相关技术。实践表明,该技术的推广应用可有效提高缠绕式垫片的设计、制造和使用水平。     

金属垫片泄漏模型理论研究

依据分形几何理论,结合不可压缩粘性流体层流流动理论,建立基于分形参数的金属垫片泄漏模型,该模型揭示了泄漏率与密封表面形貌之间的关系。研究表明,密封表面分形维数D越大,螺栓-法兰-金属垫片密封系统越不易发生泄漏,这对于法兰和金属垫片密封表面的加工具有重要指导意义。     

Effects of the short‐fiber tip geometry and interphase properties on the interfacial debonding behavior of rubber matrix composites

An axisymmetric finite element model of a single fiber embedded in a rubber matrix was established. A cohesive zone model was used for the fiber–matrix interface because of the interfacial failure. The effect of the fiber tip shape on the interfacial debonding of short‐fiber‐reinforced rubber matrix sealing composites (SFRCs) was investigated; the shapes were flat, semi‐elliptical, hemispherical, and conoid, respectively. The initial strain of the interfacial debonding (ε₀) was obtained. We found that among the researched fiber tips, ε₀ of the SFRC reinforced with the hemispherical tip fiber appeared to be the maximum. The initial locations of interfacial debonding were also determined. The results show that the initial locations of the interfacial debonding moved from the edge to the center of the fiber tip when the ratio of the semimajor axis and semiminor axis of the semi‐elliptical fiber tip increased gradually. Further study on the effect of the interphase properties on ε₀ with the hemispherical fiber tip was conducted. The results indicate that an interphase thickness of 0.2 μm and an interphase elastic modulus of about 752 MPa were optimal for restraining the initiation of the interfacial debonding. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42774.     

一种基于情境演算的进化MAS系统

给出了一个基于情境演算的多Agent系统(MAS)建模的框架,可以帮助更好地理解和分析MAS的静态结构和动态行为,尤其是意向驱动将MAS中相互独立的元素包括实体、活动等关联起来形成MAS系统,能够随着环境的变化驱动MAS进化.