Effect of ambient wind on pressure wave generated by high-speed train entering a tunnel

Journal of Central South University - Using three-dimensional, unsteady N-S equations and k-ε turbulence model, the effect of ambient wind on the pressure wave generated by a high-speed train...     

浅析安徽地方文庙的布局特征——以寿州孔庙为例

儒学被认为是古代封建文化的正统,地方文庙也随着封建统治者对尊孔祭祀活动的升级而逐渐普及。寿州孔庙建筑群是安徽省境内始建年代较早,现存较为完整的地方文庙代表。本文以寿州孔庙建筑群为例,从特点鲜明的建筑组成,庙学合一的功能组织,礼制规范的形制格局,层层递进的序列空间等方面解析作为地方文庙建筑的典型布局特征,以期为安徽地方文庙建筑的保护研究提供参考。     

Stress-dilatancy of Zipingpu gravel in triaxial compression tests

Experimental investigations of the dilatancy and particle breakage of gravelly material from the Zipingpu concrete-faced rockfill dam, which was subjected to high-intensity seismic load during the 2008 Wenchuan earthquake, were conducted through a series of large-scale drained triaxial compression tests. A hyperbolic relation between the input plastic work and the degree of particle breakage was found for Zipingpu gravel, independent of the initial void ratio and confining pressures. The stress-dilatancy for Zipingpu gravel was analyzed and compared with data from two rounded alluvial and three angular quarried gravelly and rockfill materials in the literature. A nearly linear relationship between the dilatancy D~p and the stress ratio η was found at medium-to-large stress ratios before the peak stress ratio. The slope of the stress-dilatancy line before peak had slight dependence on the void ratio and confining pressure of the gravel. After peak, the stress-dilatancy relation shifts down compared with that before peak for the gravel specimen. The phase-transformation stress ratio decreased with increased confining pressure, with the exception of sub-rounded gravel with little particle breakage. A nearly linear relationship was found between the phase-transformation stress ratio M_f and the state parameter y for the Zipingpu gravel, regardless of the void ratio and confining pressure of the specimens.     

基于硬件架构和虚拟化扩展机制的虚拟机自省机制研究

针对现有虚拟机自省技术利用不可信被监控操作系统的内核数据结构在内存中的期望布局及内核函数构建被监控系统语义、无法抵抗直接内核数据结构操纵攻击的问题,对虚拟机自省机制的能力进行全面分析,并对利用虚拟机自省机制可应对的恶意攻击进行分类,提出更具健壮性的基于硬件体系架构和虚拟化扩展机制的虚拟机自省技术,通过硬件体系结构提供的虚拟机自省特性被动地观察与收集被监控系统信息,并利用虚拟硬件扩展机制主动地截获客户虚拟机内部的事件和指令,达到主动监控的目的.描述了基于硬件的虚拟机自省机制在系统调用序列收集与监控上的应用,并进行了效率测试分析.     

康复花园植物景观设计

康复花园是近年来新兴的一种以康复保健功能为设计主题的景观类型。通过实践表明,康复景观中园艺疗法在慢性病、思维功能障碍等康复保健治疗上,取得良好的效果。为了更有效地利用康复花园中的植物景观效应需从利用视、听、嗅、味、触5种感观建立复合的植物感知体系;针对服务人群分别设计以儿童和老人为主题的多元植物园艺活动体系;以康复人群为核心,打造适宜尺度的不同空间相组合与连贯的植物空间体验体系。在以上三方面优化康复性景观中的植物利用,将植物色彩、气味、造型,以及园林整体环境的营造相结合,满足老幼病残等弱势群体的生理及心理需求。     

基于随机存贮模型的网络营销模式库存控制策略

随机需求下由于供需无规律对商家库存管理带来压力,以网络营销下随机需求为前提,考虑了缺货损失、存货处置成本、需求概率等因素,建立随机存贮模型寻找商家最优订购批量及最优利润,通过实证分析证实模型的有用性。     

含未知参数和输出不确定性的Lipschitz非线性系统自适应观测器设计

对含未知参数且输出带有不确定性的Lipschitz非线性系统,本文提出了一种自适应观测器的设计方法。当该系统输出的不确定性部分满足Lipschitz条件时,本文给出了系统观测器的结构形式,通过黎卡提方程和矩阵不等式的求解给出观测器增益矩阵的选取方法和参数估计的自适应律, 基于Lyapunov方法证明系统的状态估计误差是一致有界的。仿真结果验证了提出的自适应观测器设计的有效性。     

三维流感病毒免疫模型研究

随着人类社会的发展,人类对于自身健康的研究越来越深入,人工免疫系统也成为了生物信息研究领域的热点.传统的动物实验虽趋于完善,却也出现了研究技术上的难关,研究员们无法通过传统的实验室环境模拟数量化的人体体内环境,更无法用人类活体做实验.这样,就产生了二维的免疫计算机模型,但也并没有完全贴切人体环境的要求.因此,我们利用Java 3D计算机三维模型以及计算机仿真方式来搭建类似于体内真实环境的人体免疫计算机模型,这可以使得人工免疫系统模型更加完善.与培养皿方式的实验相比,计算机模型的实验方式可以用于研究免疫系统智能性,对研究设计新的人工免疫系统方法很有意义.而且计算机模型具有准确性高、误报率低和稳定性好等优点.本文利用Java 3D技术,通过细胞之间的相互作用,加入对流感病毒免疫应答的仿真,结合免疫细胞的参数,模拟临床实验,期望得到一些规律性的结果.     

随机供求下农产品供应链协调模型研究

基于农产品随机供求情形,并考虑产品残值收益和缺货损失成本,研究了农产品供应商和销售商组成的二级供应链的协调问题。通过对集中控制决策和分散无协调决策时的利润分析,设计了随机供求下农产品供应链利润共享契约协调模型,在合理的利润分配参数下,供应链可以实现最优。最后,通过算例分析验证了模型的科学性和有效性。     

Preparation and characterization of high strength and high modulus PVA fiber via dry-wet spinning with cross-linking of boric acid

To improve the mechanical properties of polyvinyl alcohol (PVA) fibers, a series of PVA fibers were prepared via dry-wet spinning with cross-linking of boric acid (BA) (PVA/BA fibers), and using the mixed solvent of dimethyl sulfoxide and water. Moreover, the final PVA/BA fibers were characterized by Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), differential scanning calorimetery (DSC), thermogravimetric analyzer (TGA), powder X-ray diffraction (XRD) and yarn strength tester. Furthermore, with the increasing of BA content, FTIR analysis showed that the degree of crosslinking of BA with PVA increased. SEM images of final PVA/BA fibers presented smooth surfaces, and the diameters decreased firstly and then increased. DSC, TGA, and XRD analysis indicated that the melting temperatures, thermal properties and crystallinities first increased and then decreased with the increasing of BA content. In addition, mechanical properties measurements illustrated that the cross-linking existed at an optimal BA content of 0.3 wt%, and PVA/BA-0.3 fiber had the highest tensile strength and Young's modulus of 13.1 ± 0.4 and 360.2 ± 10.4 cN/dtex, respectively.