基于管道配置的电液位置控制系统同步特性研究

针对径锻机一级先导缸电液位置控制系统同步精度低的问题,运用AMESim软件研究了第一类管道配置对径锻机一级先导缸电液位置控制系统同步特性的影响。研究发现:系统同步误差随着管道长度的增加而增大,且伴有波动现象,管道长度为3m时最大同步误差是管道长度为1m时的1.4倍;管道长度为1m时的最大同步误差为无管道时的1.1倍;管道材料的杨氏弹性模量越小,对应系统的同步误差越大。     

窖水中主要无机离子对光催化灭除大肠杆菌(E.coli)的影响研究

采用自主开发的N-TiO_2作为光催化剂,在流动相光催化反应装置中,对窖水中所含Ca~(2+)、Cl~-、CO_3~(2-)、HCO_3~-、SO_4~(2-)等主要无机离子对光催化剂灭除E.coli的影响,以及复配模拟窖水和实际窖水对光催化灭除E.coli的影响进行了实验研究,并分析了其影响机理。实验结果表明:Ca~(2+)、HCO_3~-对光催化灭除E.coli有抑制作用,CO_3~(2-)对光催化灭除E.coli有明显的促进作用,而SO_4~(2-)、Cl~-对光催化灭除E.coli无影响。在对实际窖水进行光催化灭除E.coli菌落总数的实验中,经60min反应,窖水中菌落总数和总大肠菌群均为零,达到国家饮用水卫生标准,说明自主开发的NTiO_2光催化剂在农村窖水深度处理灭除E.coli效果好,可推广应用。     

高速铁路路堤传递地基差异沉降特性及控制限值研究

为研究高速铁路地基差异沉降在路堤中的传递扩散特性,运用有限元方法,分析了路基在小变形条件下地基差异沉降与路基面不均匀变形的映射关系,并在得到土工离心模型试验校正的基础上,讨论了地基差异沉降模式、路堤高度等因素对路基面不均匀变形的影响规律.研究表明:地基差异沉降在路堤中的扩散程度随地基差异沉降渐变段长度与路堤高度比值的增大而减小,比值大于3~5以后,地基差异沉降与路基面不均匀变形具有良好的一致性;路基面不均匀变形与地基差异沉降呈正相关性,并随路堤高度、地基差异沉降渐变段长度的增加而减小;基于路基面不均匀变形限值提出了地基差异沉降控制标准,丰富了高速铁路路基沉降变形控制技术指标体系.     

Ti-Nb-Fe-Sn合金显微组织和力学性能的研究

研究了Ti-(22, 24, 26, 28)Nb-2Fe-4Sn合金的显微组织和力学性能。使用真空非自耗电弧熔炼炉制备合金铸锭,均匀化处理后对合金铸锭进行冷轧和固溶处理。使用X射线衍射仪和光学显微镜对其物相和微观组织进行分析。通过拉伸试验测定了合金的力学性能,使用扫描电子显微镜观察了拉伸样品断口形貌。结果表明,Ti-(22, 24, 26, 28)Nb-2Fe-4Sn合金具有单一β相。Nb的加入使合金的β相稳定性提高,合金的变形机制由孪晶变形转变为位错滑移变形,孪晶诱导塑性变形使得合金具有较高的伸长率。所有合金拉伸断口呈韧性断裂特征。Ti-26Nb-2Fe-4Sn合金的弹性模量为59 GPa,伸长率为19%,抗拉强度为621 MPa,具有良好的生物医学应用前景。     

Meta-analysis of genome-wide association data and large-scale replication identifies additional susceptibility loci for type 2 diabetes

Genome-wide association (GWA) studies have identified multiple loci at which common variants modestly but reproducibly influence risk of type 2 diabetes (T2D). Established associations to common and rare variants explain only a small proportion of the heritability of T2D. As previously published analyses had limited power to identify variants with modest effects, we carried out meta-analysis of three T2D GWA scans comprising 10,128 individuals of European descent and approximately 2.2 million SNPs (directly genotyped and imputed), followed by replication testing in an independent sample with an effective sample size of up to 53,975. We detected at least six previously unknown loci with robust evidence for association, including the JAZF1 (P = 5.0 x 10(-14)), CDC123-CAMK1D (P = 1.2 x 10(-10)), TSPAN8-LGR5 (P = 1.1 x 10(-9)), THADA (P = 1.1 x 10(-9)), ADAMTS9 (P = 1.2 x 10(-8)) and NOTCH2 (P = 4.1 x 10(-8)) gene regions. Our results illustrate the value of large discovery and follow-up samples for gaining further insights into the inherited basis of T2D.     

基于智能虚拟环境的地铁站台仿真系统

实现了一个用于列车驾驶培训的地铁站台仿真系统.系统由一个可被感知的站台虚拟环境和虚拟乘客系统组成.站台环境由静态场景、动态场景两部分组成,可在用户控制下发生变化.虚拟乘客通过感知站台环境的变化做出行为判断与动作.乘客仿真模型采用分层结构,分别实现环境感知、决策、行为选择、动作实现与实时绘制.目前,该系统已用于地铁列车仿真器,成为培训司机站台操作的工具.     

Novel cued search strategy based on information gain for phased array radar

A search strategy based on the maximal information gain principle is presented for the cued search of phased array radars. First, the method for the determination of the cued search region, arrangement of beam positions, and the calculation of the prior probability distribution of each beam position is discussed. And then, two search algorithms based on information gain are proposed using Shannon entropy and Kullback-Leibler entropy, respectively. With the proposed strategy, the information gain of each beam position is predicted before the radar detection, and the observation is made in the beam position with the maximal information gain. Compared with the conventional method of sequential search and confirm search, simulation results show that the proposed search strategy can distinctly improve the search performance and save radar time resources with the same given detection probability.     

Efficient combination rule of Dezert-Smarandache theory

The Dezert-Smarandache theory （DSmT） is a useful method for dealing with uncertainty problems. It is more efficient in combining conflicting evidence. Therefore, it has been successfully applied in data fusion and object recognition. However, there exist shortcomings in its combination rule. An efficient combination rule is presented, that is, the evidence＇s conflicting probability is distributed to every proposition based on remaining the focal elements of conflict. Experiments show that the new combination rule improves the reliability and rationality of the combination results. Although evidences conflict another one highly, good combination results are also obtained.     

航空电子综合化数据传输网络建模方法研究

采用Petri网理论对航空电子综合化数据传输网络系统的建模方法进行研究。通过对研究对象的基本假设、研究对象与Petri网理论之间的关系,给出了航空电子综合化数据传输网络系统的Petri网模型     

一种基于分形理论的语音分割新方法

语音是由混沌的自然音素组成的,而分形可以很好地为成混沌状态的自然音素建模．语音波形具有分形特征,将分形用于改善语音识别技术越来越受到重视．语音的特性决定了每一个音素展现其固有模式,因此相邻音素之间的分维值不同．通常求取语音波形的分维值轨迹可把人的发音分割成句子、词、甚至音素．实验证明,该方法在语音分割中取得了很好的效果．