安徽省农村房屋抗震性能调查及分析

以安徽省农村房屋为例,进行抗震性能调查,并从农村房屋建筑的年代分布、结构形式及构造特征等方面进行了分析研究,指出了农村房屋抗震存在的不足,提出了提高农村房屋建筑抗震性能的具体措施。     

处理二维浅水流动中动边界问题的淹没节点法

针对浅水流动中的动边界问题，本文设计一种淹没节点方法，根据网格单元各节点的被淹没情况，即单元水面高程和各节点高程的差值，对单元平均水深和单元界面处平均水深进行修正，运用高精度无振荡的FDS格式和有限体积法求解含有动边界的二维浅水方程。除对单元水深和界面水深进行修正外，离散方程形式与传统方法相同，实现过程简单。应用该方法对两个典型算例进行了数值模拟，模拟结果分别与其他学者的模拟结果和精确解高度吻合。表明本文方法精度较高、实现过程简单、可以有效解决浅水方程的间断、动边界和河床起伏问题。     

大规模优化及其在上限定理有限元中的应用

通过引进变量将原问题变为标准的内点法问题 ,将原问题的可行域仿射为单位球体区域 ,在仿射后的区域内向目标函数减少最快的方向移动 ,寻求问题的最优解 ,最后进行逆变换 ,将得到的解换回到原可行域。     

A comparative study between discrete and continuum models to simulate concrete fracture

We present a comparative study between models that follow the two main trends to study fracture of quasi-brittle materials like concrete. On the one hand, we focus on a discrete model that represents the fracture process by cohesive elements that are inserted in the original mesh only when the opening condition is met. Such elements also implement contact and friction algorithms. Besides, mesh size is selected so as to represent the inter-locking effect between the crack surfaces. Everything considered, this approach leads to an explicit and multiscale modeling of fracture. On the other hand, we analyze a continuum model based on the strong discontinuity approach. It localizes damage in bands that are narrowed to the limit of having null width and thus, simulate the fracture surface. The initiation and propagation processes are modeled by a bifurcation analysis that searches for the surfaces where damage can be localized at every step. Finally, we use both approaches to do 3D simulations of fracture tests in concrete that allow an evaluation of their relative performance.     

邻域相关信息的改进Census变换立体匹配算法

针对传统Census变换在视差不连续区域和噪声干扰情况下误匹配率较高的情况,提出了一种利用邻域相关信息的改进Census变换立体匹配算法。根据邻域像素的相关信息,将传统的Census变换中像素与邻域像素的差异应用2位信息表示,使变换后的图像在视差不连续区域的信息表示更为丰富,同时减少噪声对匹配质量的影响。通过并行化自适应匹配代价聚合、亚像素插值、左右一致性约束、遮挡区插值,最终得到了稠密视差图。经Middlebury立体图片测试表明,该算法结构简单,复杂度低,具有较高的鲁棒性,有效地提高了匹配精度。     

农村不同排污方式水质调查与治污新策略

目前全国各地正在积极推进农村生活污水整治工作,为了该项工作能够合理选用最佳排污方式即污水收集方式,选取厦门某个亟待整治的村庄,针对该村3种不同排污方式即污水经PVC管道排放、排水沟排放和荒地排放,开展了水质调查。调查结果表明,从荒地排出的污水水质最好,经简单沉淀后有望满足农田灌溉标准;其次是硬化排水沟;水质最差的是PVC管道。基于该调查结果,提出农村污水整治工作应改变目前简单效仿城市采用管道排污的思维,建议充分利用农村中现有荒地这种天然土壤渗滤系统;充分利用农村现有排水沟进行排污以便沿程削减污染物质,应尽量避免新建排污管网。最后,本文还提出一种治污新措施即集生态景观与"渗、蓄、滞、净、排"功能于一体的LID新型排水沟。     

A theoretical study of two‐dimensional grease flow in regions with discontinuities

This paper presents a theoretical analysis of two‐dimensional grease flow through an asymmetric discontinuity. The behaviour of the fluid is described using Navier—Stokes equations, numerically solved by the finite‐element method. The FLFI program was used for this purpose. For this type of discontinuity, the velocity profile in the lubricant film, the shape and the dimensions of the stagnant core, the flow capacity, and the pressure distribution have been obtained. The results are useful in the design of bearings, if one considers the discontinuities in the carrying region as orifices, canals, or pockets for lubrication.     

Phytoplankton species richness as an ecological indicator in a subtropical,human-regulated,fragmented river

Since the serial discontinuity concept (SDC) of rivers is proposed, few studies have tested it in a highly fragmented river ecosystem. In this study, environmental factors, phytoplankton species richness, and SDC predictions were demonstrated along the 13 cascade dams in a subtropical river (China). Our results indicated that among environmental factors, water temperature and transparency have seasonal differences, and river width has spatial differences; total species richness (TSR) increases from upstream to downstream, and distance is the reason for its variation. In addition, TSR also has spatial variations in each cascade dam, with the maximum or minimum value of each cascade section often occurring near the dam. A predictive model was constructed and revealed that seasonal differences in species richness were more significant than spatial differences, which were mainly observed during wet periods. Taken together, these results suggest that the construction of cascading dams enhances spatial differences in phytoplankton species richness, especially during periods of abundant water. In addition, environmental parameters such as water temperature, pH, and DO and TSR all support SDC predictions. In the future, we will continue to investigate this aquatic ecosystem to study more phytoplankton-related indices affected by the cascade damming, and hope to fully validate the SDC predictions.     

一种计算异质结价带与导带阶跃的简便方法

利用带隙经验公式、LCAO方法以及韦加定律，提出了一种计算AlGaInP异质结价带与导带阶跃的方法。该方法具有简便、精确和实用的特点。