反拱法碳纤维加固RC梁的数值模拟分析

采用动力设备将钢筋混凝土梁向上反拱一定的弧度,然后在梁的下部外贴碳纤维布（CFRP）,待碳纤维布养护完全后,卸载,此时后加的碳纤维布与原钢筋混凝土梁同时进入工作状态。作者采用分析软件ANSYS模拟此过程,通过与直接用碳纤维布加固RC梁进行比较,得出反拱法加固RC梁能有效提高其承载能力,对类似工程具有一定的借鉴意义。     

安县晓坝镇震后新建场址主要岩土工程问题及对策

安县晓坝镇处于＂5.12＂汶川大地震极重灾区,受灾严重,不具备重建条件,需选址重建。在野外详细调查的基础上,通过现场勘查和室内试验,深入研究了晓坝镇灾后新建场址的主要岩土工程问题。研究表明,新建场址主要土层为粉质粘土和淤泥质土,属高压缩性软弱土;地下水埋深浅,对基础施工和地基土承载力影响大;建筑场地类别Ⅱ类,属抗震不利地段。提出了深层水泥土搅拌法和换填地基两种软基处理方案,以及加强地基基础抗震设计等措施。     

可数aD-空间的研究

研究了可数aD-空间的一些性质,获得了如下结果：可数aD-空间的闭子空间是可数aD-空间;如果X=Y∪Z,X为T1空间,y和Z都为可数aD-空间,则X是可数aD-空间;若空间X是可数个闭的可数aD-空间的并,那么,X是可数aD-空间;可数aD-空间在完备映射下的原象空间是可数aD-空间．     

楼梯对不同刚度钢筋混凝土框架结构地震反应的影响

为研究楼梯对结构地震反应的影响,利用ETABS设计了2个不含楼梯的钢筋混凝土框架模型和2个包含楼梯的具有不同初始抗侧刚度的钢筋混凝土框架模型,采用振型分解反应谱法对模型进行了弹性地震反应对比计算分析。结果显示：楼梯参与结构整体计算后,结构的抗侧刚度、振动模态、结构基底剪力及梯间框架柱内力分配比例等均明显变化,且影响程度因原框架抗侧刚度大小不同而异。建议当前框架结构设计可以适当提高结构抗侧刚度,以减小楼梯对结构地震反应的改变程度,降低考虑楼梯参与结构整体抗震分析计算的复杂性。     

New CFD Validation Method with Application to Verify Computations of Near Wall Flows

For high Re number flows, a new computational fluid dynamics (CFD) validation method, namely, wall-surface compatibility criteria method and also called Gaos criteria, is proposed to verify near wall flows. As examples, Gaos criteria method and other two CFD verification methods (analytic solutions method and grid convergence analysis) are used to verify FLUENTs near wall flows solutions for two-dimensional incompressible laminar stagnation-point flows. The exact solution of the Navier-Stokes equations for laminar stagnation-point flows satisfy accurately all Gaos criteria, numerical simulations of laminar stagnation-point flows show that when physical parameters (the pressure coefficient and the Stanton number at wall surface) achieve convergence with more and more fine-screen grid, a part of Gaos criteria are not satisfied.     

团簇态的概率隐形传送(英文)

提出一个传送未知团簇态的方案.在这个方案中,传送者利用一个非最大的三粒子纠缠态和一个非最大的四粒子纠缠态作为量子通道,当接收者执行适当的幺正操作时,可以以一定的概率完成未知团簇态的量子隐形传送.     

Sintering technology for micro heat pipe with sintered wick

In order to study reasonable sintering technological parameters and appropriate copper powder size range of micro heat pipe (MHP) with the sintered wick, the forming principle of copper powders in wicks and MHP’s heat transfer capabilities were first analyzed, then copper powders with different cell sizes and dispersions were sintered in RXL-12-11 resistance furnace under the protection of the hydrogen at different sintering temperatures for different durations of sintering time, and finally the sintered wicks’ scanning electron microscope (SEM) images and their heat transfer capabilities were analyzed. The results indicate that the wick sintered with copper powders of larger cell size or smaller size range has better sintering properties and larger heat transfer capabilities; and that the increase of either sintering temperatures or sintering time also helps to improve the wick’s sintering properties and heat transfer capabilities, and the former affects more obviously than the latter. Considering both its manufacturing cost and performance requirements, it is recommended that copper powders with the size range of 140–170 μm are sintered at 900–950°C for 30–60 min in practical manufacturing. In addition, two approaches to improve wick’s porosity are also proposed through theoretical analysis, which suggests that the larger the wick’s porosity, the better the heat transfer capabilities of the MHP.     

Prediction-based energy-efficient target tracking protocol in wireless sensor networks

A prediction based energy-efficient target tracking protocol in wireless sensor networks (PET) was proposed for tracking a mobile target in terms of sensing and communication energy consumption. In order to maximize the lifetime of a wireless sensor network (WSN), the volume of messages and the time for neighbor discovery operations were minimized. The target was followed in a special region known as a face obtained by planarization technique in face-aware routing. An election process was conducted to choose a minimal number of appropriate sensors that are the nearest to the target and a wakeup strategy was proposed to wakeup the appropriate sensors in advance to track the target. In addition, a tracking algorithm to track a target step by step was introduced. Performance analysis and simulation results show that the proposed protocol efficiently tracks a target in WSNs and outperforms some existing protocols of target tracking with energy saving under certain ideal situations.     

Status of research on biogenic coalbed gas generation mechanisms

Biogenic coalbed gas,how it is generated and the geochemical characteristics of the gas are gaining global attention.The ways coalbed gas is generated,the status of research on the generation mechanism and the methods of differentiating between biogenic gasses are discussed.The generation of biogenic coalbed methane is consistent with anaerobic fermentation theory.Commercial biogenic coalbed gas reservoirs are mainly generated by the process of CO2 reduction.The substrates used by the microbes living in the coal include organic compounds,CO2,H2 and acetate.The production ratio and quantity of biogenic coalbed methane depend on the exposed surface area,the solubility and permeability of the coal and the microbial concentration in the coal seam.It is generally believed that biogenic coalbed gas has a value for σ13C1＜-5.5%,C1/C1+＞0.95.The H isotope ratio is controlled by both the environment and the generation mechanism:typically σD1＜-20%.Biogenic methane formed by CO2 reduction has more σD1 than that formed by acetate fermentation.     

扭断盖滚压封口机滚压封口设计

研究了扭断盖滚压封口机的滚压封口部分,参考了目前市场上使用的扭断盖滚压封口机,并提出了改进意见。