江边水电站首部枢纽引水防沙设计研究

江边水电站的泥沙问题突出.通过水工模型试验对该枢纽的相关泥沙问题展开了研究.试验结果表明:在原枢纽布置方案的基础上增设扰沙坎,可以有效地降低沙面高程,保证进水口“门前清”;汛期限制水位运行,当流量或淤积达到一定程度时停机拉沙,可以保证水库淤积平衡后调节库容最大;电站可不设置沉沙池.库尾张家沟泥石流的主要影响是增大干流局...     

泸定水电站大坝反滤料生产系统工艺流程设计

泸定水电站大坝反滤料生产系统承担着50万m3反滤料的生产任务.该系统在设计过程中,对料源情况、反滤料质量技术要求和大坝填筑工期进度等客观条件进行了深入分析和充分论证,最终确定了反滤料生产系统的生产能力(毛料400 t/h、成品料350 t/h)和建设规模,提出了有针对性的工艺流程.目前该系统已建成投产,产品质量稳定,满足设计要求.     

海岸裂流的浮子示踪法实验测量

研究模型实验中采用浮子示踪法测量沙坝海岸裂流的方法,讨论了该方法的具体技术实现和测量结果的精度。实验中裂流由波浪在垂直岸线的直墙上的反射所形成的两列交叉的波浪生成。通过处理CCD图像的浮子轨迹得到了流场的详细速度分布,如旋涡分布等,显示了该方法优于流速仪定点测量的一些特点。与ADV流速仪测量结果的对比表明,由浮子轨迹得到的表层平均流速具有可靠的精度,特别是也可以应用于波浪破碎产生的裂流这样复杂流场的测量。     

基于GIS的乌江流域新安江模型参数率定

为了使新安江模型的运用更能真实反映流域的基本特征及产汇流机理,利用地理信息系统空间分析的功能,由数字高程模型导出乌江武隆以上流域的流域排水网,并在此基础上提取汇流长度及坡度等地形特征值。在地理信息系统平台上,计算出流域下垫面的植被、土壤、地貌等特征值,并将其与流域模型参数建立相关关系。结果表明,各流域模拟的确定性系数及模拟精度均较高。因此,预报结果更加合理,理论依据也更加可靠。     

Traffic-information-utilized low-complexity relay selection for two-way AF relaying networks

This paper investigates a two-way amplify-and-forward multiple relaying network (TWMR-AF) and presents a novel relay selection scheme, which is appropriate for different traffic patterns and has very low implementation complexity, rendering it very attractive for practical systems. Assuming the TWMR-AF over Nakagami-m fading, the approximate expression of the overall outage probability is derived, and the diversity and code gains are then obtained. The analytical results indicate that the proposed policy achieves better outage performance than the traditional max-min relay selection scheme, as validated by the simulation results.     

Spindle-shaped microfluidic chamber with uniform perfusion flows

The reaction chamber is important due to its wide applications. Based on the idea of the bionics, a novel spindle-shaped chamber (S-chamber) for microfluidics was designed to provide uniform flow and eliminate stagnant corners for microchannels. The computational fluid dynamics simulation results demonstrate that these S-chambers have a better performance compared to the conventional diamond-shaped chambers. An S-chamber with the optimized shape, which consists of a rectangle reaction region interfaced to the inlet/outlet channel through an expansion region with smooth arc edges, was fabricated by micromolding of polydimethylsiloxane. This S-chamber was fixed into a microreactor and mounted horizontally on a synthesizer for biochemical reactions. Solvent perfusion experiments and synthetic optimization experiments for in situ synthesis of peptide nucleic acids microarray were performed. The experimental results indicate that the newly designed and fabricated S-chamber provides excellent homogeneous perfusion flows. This type of S-chamber is designed for the most convenient fixation in the horizontal direction, without the need to consider the complicated effect caused by other housing directions. It has a wide application for cell culturing, microarray synthesis, gene hybridization, and many other microfluidic system-based techniques requiring uniform flow conditions.     

A method for shape and topology optimization of truss-like structure

We present a method for the shape and topology optimization of truss-like structure. First, an initial design of a truss-like structure is constructed by a mesh generator of the finite element method because a truss-like structure can be described by a finite element mesh. Then, the shape and topology of the initial structure is optimized. In order to ensure a truss-like structure can be easily manufactured via intended techniques, we assume the beams have the same size of cross-section, and a method based on the concept of the SIMP method is used for the topology optimization. In addition, in order to prevent intersection of beams and zero-length beams, a geometric constraint based on the signed area of triangle is introduced to the shape optimization. The optimization method is verified by several 2D examples. Influence on compliance of the representative length of beams is investigated.     

为互联网和数据中心业务定制的服务器——云计算资源池的最佳选择

随着云计算技术的不断发展,基于云计算定制的服务器在互联网和数据中心的应用日益广泛,各种解决方案层出不穷。本文通过分析服务器和云计算的技术特点,比较各种硬件解决方案的异同,确定最适合云计算资源池应用的硬件支撑方案。     

Amultiplemaneuvering targets tracking algorithm based on a generalized pseudo-Bayesian estimator of first order

We describe the design of a multiple maneuvering targets tracking algorithm under the framework of Gaussian mixture probability hypothesis density (PHD) filter. First, a variation of the generalized pseudo-Bayesian estimator of first order (VGPB1) is designed to adapt to the Gaussian mixture PHD filter for jump Markov system models (JMS-PHD). The probability of each kinematic model, which is used in the JMS-PHD filter, is updated with VGPB1. The weighted sum of state, associated covariance, and weights for Gaussian components are then calculated. Pruning and merging techniques are also adopted in this algorithm to increase efficiency. Performance of the proposed algorithm is compared with that of the JMS-PHD filter. Monte-Carlo simulation results demonstrate that the optimal subpattern assignment (OSPA) distances of the proposed algorithm are lower than those of the JMS-PHD filter for maneuvering targets tracking.