大断面导流洞进出口开挖支护设计与施工

随着水电开发建设的加速,在水电工程中出现的大断面导流洞越来越多.在这些大断面导流洞的施工过程中,特别是导流洞的进口渐变段和出口段,容易出现安全问题甚至塌方事故.对目前国内部分已完工或正在施工的大断面导流洞进出口的开挖支护设计与施工方案进行了总结,并以在不同地质条件下的典型案例加以说明,可供类似工程参考和借鉴.     

金安桥大坝碾压混凝土快速施工关键技术

金安桥水电站大坝工程规模大、工期紧、技术复杂、施工强度高。针对其玄武岩骨料碾压混凝土可碾性差、坝体布置复杂以及立体气候条件明显等诸多不利于碾压混凝土施工的难题,通过配合比设计、入仓方案、仓面分区、层间结合、温控防裂等关键技术的优化和技术创新,保证了碾压混凝土快速施工和度汛等重大节点工期目标的按期实现。     

宁东能源化工基地水土保持生态环境动态监测分析

通过采用卫星遥感、地面定点和野外查等监测技术手段,对宁东基地开发建设前（2000年）和开发建设初期（2007年）两个时段土地利用、植被盖度、土壤侵蚀、水土保持措施等水土保持生态环境影响因子分别进行监测。综合分析结果表明,宁东基地自2000年以来土地利用结构改善,植被覆盖呈好转趋势,虽然局部水土流失加重,但整体土壤侵蚀强度降低,整体生态环境处于好转状态。     

建设生态库区 实现重庆经济社会可持续发展

1.保护生态,促进人水和谐共处 重庆按照＂预防为主、保护优先、综合治理＂的思路,围绕建设＂宜居重庆＂＂森林重庆＂＂健康重庆＂,大力实施库区生态保护、水环境治理工程,极大改善了库区环境条件,使库区的水体变得更加清澈、天空变得更加明净、     

曝气强度对膜生物流化床运行特性的影响

将膜分离技术与生物流化床工艺有机结合,采用结合后的膜生物流化床(Membrane-Fluidized Bed Bioreactor,MFBB)处理城市污水。试验以气水比作为曝气强度指标,考察了在气水比为15∶1、25∶1和45∶1的情况下MFBB的运行特性及曝气强度对其运行特性的影响。试验结果表明,系统的曝气强度并非越高越好,而是存在一个最佳值,本试验条件下的最佳气水比为25∶1,此时CODCr、NH3—N、TN去除率分别可达96.91%、98.02%和60.12%。稳定阶段的脱氢酶活性平均值达23.8μgTF/(mgMLSS.h)。     

河道生态护坡技术在宜春市城市防洪工程中的运用

根据国内有关城市河道治理的先进经验,采用了生态护坡技术在江西省宜春市城市防洪工程中的应用,取得显著效果.     

How commercial involvement affects open source projects: three case studies on issue reporting

Whereas most research on Internetware has focused on new technologies for keeping track of a changing Internet,little attention has been paid to the software development process.A large portion of the software running the Internet is open source software.Open source software is developed both by volunteers and commercial companies,often jointly.Companies get involved in open source projects for commercial reasons,and bring with them a commercial software development process.Thus,it is important to understand how commercial involvement affects the software development process of open source projects.This article presents case studies of three open source application servers that are being developed jointly by a volunteer community and one primary software company.We are interested in better understanding developer behavior,specifically task distribution and performance,based on whether the developer is an external contributor,e.g.,a volunteer working in their spare time,or a commercial developer from inside the primary backing company who is being paid for their time.To achieve this,we look at issue reporting as an example of commercial involvement in open source projects.In particular,we investigate the distribution of tasks among volunteers and commercial developers by studying the source of reported issues and quantify the task performance on user experience via the issue resolution speed.We construct measures based on historical records in issue tracking repositories.Our results show that,with intensified commercial involvement,the majority of issue reporting tasks would be undertaken by commercial developers,and issue resolution time would be reduced,implying a better user experience.We hope our methods and results provide practical insights for designing an efficient hybrid development process in the Internetware environment.     

Efficient bidirectional quantum secure communication with two-photon entanglement

An efficient bidirectional quantum secure communication protocol is proposed with two-photon entanglement. Compared with the previous protocol proposed by Shi et al., our protocol can achieve higher efficiency. Meanwhile, for the same length secret messages, only half of entangled photon pairs need to be prepared in our protocol. And the number of classical bits in public classical communication is also a half of that in the previous protocol. Moreover, the information leakage does not exist in our scheme.     

Stability and static output feedback stabilization for a class of nonlinear discrete-time singular switched systems

In this paper, the stability and static output feedback stabilization problems for a class of nonlinear discrete-time singular switched systems are discussed. First, based on Lyapunov theory and the implicit function theorem, linear matrix inequalities sufficient conditions are developed which guarantee that the nonlinear discrete-time singular switched systems are regular, causal, have unique solution in a neighborhood of the origin, and are uniformly asymptotically stable. Then, with these conditions, and based on singular value decomposition approach, the design method of static output feedback controllers is given. Last, numerical examples are provided to illustrate the effectiveness of the proposed methods.     

Multipartite electronic entanglement purification using quantum-dot spin and microcavity system

This paper presents an entanglement purification protocol of multipartite electronic spin entangled state resorting to quantum-dot (QD) spin and micro cavity coupled system. The QD and microcavity coupling system is used to construct parity check detectors which provides a novel experimental platform of quantum information processing with photon and solid qubit. In this proposed protocol, the mixed multi-electron entangled state ensemble can be purified efficiently.