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   185篇
  免费   8篇
  国内免费   6篇
电工技术   18篇
综合类   6篇
金属工艺   7篇
机械仪表   39篇
建筑科学   1篇
矿业工程   1篇
能源动力   5篇
武器工业   2篇
无线电   30篇
一般工业技术   6篇
自动化技术   84篇
  2023年   1篇
  2022年   1篇
  2021年   3篇
  2020年   5篇
  2019年   3篇
  2018年   5篇
  2016年   5篇
  2015年   5篇
  2014年   11篇
  2013年   14篇
  2012年   10篇
  2011年   16篇
  2010年   18篇
  2009年   8篇
  2008年   10篇
  2007年   16篇
  2006年   14篇
  2005年   10篇
  2004年   8篇
  2003年   6篇
  2002年   5篇
  2001年   8篇
  2000年   2篇
  1999年   6篇
  1998年   2篇
  1997年   2篇
  1995年   1篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1972年   1篇
排序方式: 共有199条查询结果,搜索用时 15 毫秒
1.
Constructing efficient and stable bifunctional electrocatalysts for overall water splitting remains a challenge because of the sluggish reaction kinetics. Herein, the core-shell hybrids composed of Co(PO3)2 nanorod core and NiFe alloy shell in situ grown on nickel foam (NiFe/Co(PO3)2@NF) are synthesized. Owing to the hierarchical palm-leaf-like structures and strong adhesion between NiFe alloys, Co(PO3)2 and substrates, the catalyst provides a large surface area and rapid charge transfer, which facilitates active sites exposure and conductivity enhancement. The interfacial effect in the NiFe/Co(PO3)2 core-shell structure modulates the electronic structure of the active sites around the boundary, thereby boosting the intrinsic activity. Benefiting from the stable structure, the durability of the catalyst is not impaired by the inevitable surface reconfiguration. The NiFe/Co(PO3)2@NF electrode presents a low cell voltage of 1.63 V to achieve 10 mA cm?2 and manifests durability for up to 36 h at different current densities.  相似文献   
2.
3.
如何有效减少配电网重构中不可行解的产生是提高搜索速度的重要环节。为提高搜索效率,在对网络进行拓扑简化的基础上,提出一种基于环路矩阵分块重组策略的配电网重构预处理方法,实现了解空间压缩与分解。结合该策略,以布谷鸟搜索算法及其改进算法为例对IEEE33节点系统和119节点系统进行了算例仿真,结果表明结合环路矩阵分块重组策略后能够有效避免不可行解的产生,算法只在少数可行范围内进行搜索,搜索范围减少,计算速度与寻优成功率显著提高,验证了提出策略的有效性;最后将此策略运用于多种智能算法,对比结果表明该策略能使算法在性能上得到显著提升,验证了所提策略的适用性。  相似文献   
4.
The objective of this paper is to investigate the optimal allocation of capacity investments at the tactical decision-making level by incorporating the configuration characteristics of selected system alternatives comprising Dedicated Manufacturing Systems (DMS) and Reconfigurable Manufacturing Systems (RMS). Particularly, sequencing of stages in a series or a parallel configuration impacts the responsiveness in addressing capacity change requirements. We analyze what type of configuration is more suitable for a manufacturer in terms of service level and cost. We propose a mixed integer programming model by incorporating various ramp-up time patterns, which define system scalability lead time. By solving the MIP model to optimality, we aim to see how capacity is allocated to RMS and DMS based on system cost, system responsiveness, and reconfiguration speed. A discrete event simulation model is used to validate the MIP results under uncertain demand scenarios.  相似文献   
5.
6.
Power loss reduction has an important role in operating electric distribution network system. There are a lot of methods for reduction power loss such as capacitor placement, distributed generation placement and electric distribution network reconfiguration (EDNR). Among these methods, the EDNR is an efficient technique to reduce power loss due to without taking any costs. However, the EDNR problem is a nonlinear, discrete problem and lots of extreme points. Therefore, it is necessary to have efficient methods for solving the EDNR problem. In this paper, an improved cuckoo search algorithm (ICSA) is proposed for solving the EDNR problem. In which, based on disadvantages of exploration and exploitation process of cuckoo search algorithm (CSA) for solving the EDNR problem, a local search mechanism is added to exploit candidate solutions existing around the current best solution. The calculated results on the simple distribution networks to complex distribution networks show that ICSA has ability for finding the global optimal solution with much smaller iterations and better quality of obtained solution compared with CSA and some other improved versions of CSA. The performance comparisons with other existing methods available in previous studies and the software of Power System Simulator/Advanced Distribution Engineering Productivity Tool (PSS/ADEPT) also lead to the better electric distribution network configuration with smaller total power losses. As a result, ICSA is a potential and reliable method for solving the EDNR problems.  相似文献   
7.
Tracking Area (TA) design is one of the key tasks in location management of Long Term Evolution (LTE) networks. TA enables to trace and page User Equipments (UEs). As UEs distribution and mobility patterns change over time, TA design may have to undergo revisions. For revising the TA design, the cells to be reconfigured typically have to be temporary torn down. Consequently, this will result in service interruption and “cost”. There is always a trade-off between the performance in terms of the overall signaling overhead of the network and the reconfiguration cost. In this paper, we model this trade-off as a bi-objective optimization problem to which the solutions are characterized by Pareto-optimality. Solving the problem delivers a host of potential trade-offs among which the selection can be based on the preferences of a decision maker. An integer programming model has been developed and applied to the problem. Solving the integer programming model for various cost budget levels leads to an exact scheme for Pareto-optimization. In order to deliver Pareto-optimal solutions for large networks in one single run, a Genetic Algorithm (GA) embedded with Local Search (LS) is applied. Unlike many commonly adopted approaches in multi-objective optimization, our algorithm does not consider any weighted combination of the objectives. Comprehensive numerical results are presented in this study, using large-scale realistic or real-life network scenarios. The experiments demonstrate the effectiveness of the proposed approach.  相似文献   
8.
针对现有流媒体算法在异构环境下性能恶化的问题,论文提出一种支持用户异构性的可重构流媒体调度算法——RSMS算法。该算法引入了追赶流的概念,能重构追赶流的速率来服务于具有不同接收带宽的异构用户,并最终通过流合并达到资源共享的目的。分析了RSMS算法的最佳组播调度间隔、所需的平均服务器带宽和服务器带宽需求分布。仿真实验表明该算法简单高效,可扩展性好。  相似文献   
9.
可重构多处理器阵列上的容错技术可用来重构含有故障单元的处理器阵列,以便获得最大可用的目标阵列。现有的研究成果主要侧重于重构算法的构造,还没有涉及对重构后目标阵列的同步通讯性能的研究。提出了一种改善目标阵列同步通讯性能的电路优化算法,用来降低目标阵列行与行之间通讯的延时,使得相邻两行处理器的通讯尽可能达到同步。实验结果表明,提出的算法对不同大小、不同故障率的阵列都有相应的同步通讯性能的改善。  相似文献   
10.
本文提出了一种基于蚁群系统的配电网重构算法(ACSA)[12],该算法用于减少在正常运行情况下的电能损耗的问题。结合相应的数学模型和算法,对一个典型的配电网重构的问题进行了验证。基本蚁群算法的缺点是收敛速度慢和进化停滞,本文提出了一些新的措施来克服这些缺点。  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