首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   263篇
  免费   0篇
  国内免费   1篇
系统科学   23篇
丛书文集   1篇
教育与普及   5篇
理论与方法论   1篇
现状及发展   1篇
综合类   233篇
  2016年   1篇
  2015年   2篇
  2012年   7篇
  2011年   11篇
  2010年   15篇
  2009年   35篇
  2008年   1篇
  2007年   1篇
  2005年   5篇
  2004年   19篇
  2003年   17篇
  2002年   9篇
  2001年   9篇
  1999年   2篇
  1998年   24篇
  1997年   37篇
  1996年   31篇
  1995年   20篇
  1994年   6篇
  1993年   6篇
  1992年   4篇
  1990年   1篇
  1988年   1篇
排序方式: 共有264条查询结果,搜索用时 15 毫秒
111.
我国最新结构最大容量火电仿真机   总被引:1,自引:0,他引:1  
本文论述了“八五”攻关项目-600MW最新结构最大容量火电仿真机。其硬件采用计算机工作站,X-终端,PC机和以太网通信的结构;软件则采用UNIX操作系统下具有先进数据库管理功能的大型仿真支持环境,具有支持着仿真机的自动建模,在线调试和修改以及实时运行等功能。在国内外电站仿真机中,首次实现多媒体技术应用和用软件仿真实现了集散控制系统的全部功能。文中给出了在该仿真机上所作的电站典型工况的仿真试验及其响应结果。结果分析表明该机软硬件系统均令人满意  相似文献   
112.
固体氧化物燃料电池阴极材料 La_(1-x)Sr_xMnO_3 研究   总被引:1,自引:0,他引:1  
固体氧化物燃料电池以其高效、低污染等优越性被认为是未来很有希望的发电方式,越来越受到广泛关注,La1-xSrxMnO3材料是目前最受重视的阴极材料。该文采用固相反应法合成了该材料粉末,对合成反应工艺参数进行了优化。采用四电极法在空气中测定了材料的电导性能,测试温度为室温到1000℃,测试结果表明:电导率随Sr掺杂比例增加和温度升高而增大,随孔隙率的增加而变小。还对材料La1-xSrxMnO3晶体结构和烧结性能进行了研究。  相似文献   
113.
HTR-10 一回路舱室冷却系统及其特点   总被引:5,自引:0,他引:5  
10MW高温气冷实验堆(HTR-10)一回路舱室冷却系统是反应堆重要安全系统之一。由余热排出系统和屏蔽冷却系统两部分组成。非能动式余热排出系统以自然循环方式排出余热,排除了系统对外界动力的依赖性,余热最终经空气冷却器由空气自然对流排往大气。该文提出的非能动系统配以能动系统组成舱室冷却系统设计、采用可调遮热板控制辐射传热量,构成了HTR-10一回路舱室冷却系统新的设计思想和系统组成方案,并据此完成了相应的工程设计。该方案不仅简化了系统、降低了造价、缩短了工期,而且使系统的可靠性得以提高。  相似文献   
114.
多循环堆芯燃料管理优化方法   总被引:1,自引:0,他引:1  
为了更有效地提高核燃料的利用率,降低核反应堆的运行成本,不仅要研究单循环堆芯燃料管理优化问题,还必须研究多循环优化问题。在回顾现有单循环优化方法的基础上,叙述了一种处理多循环优化问题的方法。利用分步决策的优化策略,多循环优化可以分解为一个两步优化问题。第一步简化多循环优化,使用简化的反应堆物理模型对连续多个循环进行计算,获得每个单循环的优化目标。第二步按照第一步得到的目标进行单循环优化,最终得到各循环最优的组件布置。该方法可以达到延长循环工作期,提高卸料燃耗深度,降低功率峰因子等优化目标。  相似文献   
115.
Graphene has been widely used in gas-sensing applications due to its large specific surface area and strong adsorption ability. Among different forms of graphene used as gas-sensing materials, reduced graphene oxide is one of the most convenient and economical materials to integrate with Si-based electronics, which is very important to graphene-based gas sensors. In addition, the stacking structure of graphene oxide flakes facilitates absorption and detection of gas molecules. Based on reduced graphene oxide, a highly sensitive and portable gas-sensing system was demonstrated here. Solution-based graphene oxide was cast on a chip like a TF memory card and then reduced thermally. A signal acquisition system was designed to monitor resistance variation as a sign of gas concentration. This miniature graphene-based gas sensor array demonstrates a new path for the use of graphene in gas-detection technologies. And the creation of a sensitive and portable graphene gas sensor also shows great potential in fields such as medicine and environmental science.  相似文献   
116.
An abstraction method developed for the explicit linear temporal logic model checking was geared towards reducing the useless part of the state space during the abstraction period.This reduces the cost during the abstraction period relative to models requiring many useless states.A dining-philosophers example comparing this abstraction method with conventional methods indicates that a large proportion of the state space has been reduced by this abstraction method.Finally,the abstract method is shown to be correct and an analysis is given to show how such a large proportion of states can be reduced.  相似文献   
117.
This paper gives an efficient approach to reconstruct moving multiple objects(multi-object).Each object has independently rigid motion which includes translation and rotation.The traditional FBP algorithm can resolve the one-object motion problem rather well.However,it suffers from perceptible motion artifacts in multi-object cases.This paper proposes a new motion-compensated reconstruction approach with a priori knowledge of the rigid motion model.Both an FBP-type and an ART-type algorithm were derived.In ...  相似文献   
118.
<正>The World Wide Web (WWW) has revolutionized many aspects of society in the past two decades.Emerging applications of the World Wide Web have not only fostered industrial  相似文献   
119.
As mask features scale to smaller dimensions,the so-called "3-D mask effects" which have mostly been neglected before,become important.This paper properly models the 3-D thick mask effects,and then analyses the object-based inverse lithography technique using a simulated annealing algorithm to determine the mask shapes that produce the desired on-wafer results.Evaluations against rigorous simulations show that the synthesized masks provide good image fidelity up to 0.94,and this approach gives improved accuracy and faster results than existing methods.  相似文献   
120.
The life insurance industry is very interested in how a person’s lifetime is related to his wealth with financial advisors interested in how even a person’s portfolio choice affects his lifetime. This paper presents a statistical analysis combined with intuitive relationships between lifetime and wealth. Key properties of this relationship are given and then various copulas are analyzed to see whether they have these properties. Other advantages and disadvantages of these copulas for describing the dependen...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号