全文获取类型
收费全文 | 278篇 |
免费 | 4篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 7篇 |
综合类 | 19篇 |
化学工业 | 15篇 |
金属工艺 | 53篇 |
机械仪表 | 19篇 |
建筑科学 | 6篇 |
能源动力 | 3篇 |
轻工业 | 46篇 |
水利工程 | 3篇 |
无线电 | 21篇 |
一般工业技术 | 50篇 |
冶金工业 | 12篇 |
原子能技术 | 7篇 |
自动化技术 | 28篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 10篇 |
2013年 | 42篇 |
2012年 | 31篇 |
2011年 | 35篇 |
2010年 | 15篇 |
2009年 | 20篇 |
2008年 | 14篇 |
2007年 | 14篇 |
2006年 | 13篇 |
2005年 | 8篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2001年 | 1篇 |
2000年 | 4篇 |
1998年 | 4篇 |
1997年 | 22篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 1篇 |
排序方式: 共有289条查询结果,搜索用时 15 毫秒
1.
Friction and wear of Inconel 690 and Inconel 600 for steam generator tube in room temperature water 总被引:1,自引:0,他引:1
In the steam generators of nuclear power plants, the flow of cooling water can cause the tubes to vibrate, resulting in fretting wear damage due to contacts between these tubes and their supports. The tubes are made of Inconel 690 and Inconel 600 and the supports are made of STS 304. In this paper, fretting wear tests in water were performed using the materials Inconel 690 and Inconel 600 in contact with STS 304. Fretting tests using a cross-cylinder type set up were conducted under various vibrating amplitudes and applied normal loads in order to measure friction forces and wear volumes. Also, conventional sliding tests using a pin-on-disk type set up were carried out to compare these test results.In the fretting tests, friction force was found to be strongly dependent on normal load and vibrating amplitude. Coefficients of friction decreased with an increase in the normal load and a decrease in the vibrating amplitude applied. Also, the wear of Inconel 600 and Inconel 690 was predicted using a work rate model. Depending on the normal load and vibrating amplitude applied, distinctively different wear mechanisms and often drastically different wear rates occurred. It was found that the fretting wear coefficients for Inconel 600 and Inconel 690 were 9.3×10−15 and 16.2×10−15 Pa−1, respectively. This study shows that Inconel 690 can result in lesser friction forces and exhibits less wear resistance than Inconel 600 in room temperature water. 相似文献
2.
Combustion tests of pre-mixture of methane and air in constant volume combustion chamber(CVCC) have been carried out by means of flame propagation photo and gas pressure measurement,the effects of CVCC body temperature,intake pressure of pre-mixture of methane and air,equivalence ratio and location of the built-in adaptor have been investigated.The whole combustion chamber can be divided into two parts,i.e.the upper combustion chamber and the lower combustion chamber,by the built-in adaptor with through hol... 相似文献
3.
4.
重新建立了共轭凸轮开口机构的动力学模型,组成相应的弹性振动微分方程.用矩阵摄动法分析该微分方程,并设计织机的开口机构.与传统的求解方法相比,计算时间减少20%,减小综框的振动以及降低断纬频率达到65%以上. 相似文献
5.
6.
Shop-floor scheduling at shipbuilding yards using the multiple intelligent agent system 总被引:4,自引:0,他引:4
The intelligent agent system has become a typical approach to research distributed artificial intelligence and distributed problem solving. However, despite its various technical advantages, the distribution and expansion of the intelligent agent system approach has been limited because existing methodologies rely on specialized applications and therefore require intensive investment to develop new systems. In an attempt to conquer these difficulties, a standardized methodology to construct intelligent agent systems is proposed. This approach deviates from current agent system approaches of repeatedly constructing new and customized expert systems. Specifically, it provides an economical method for developing intelligent agent systems by investigating the possibility of standardizing message communication protocols in linguistics speech-act theory and by supplementing traditional algorithmic systems with intelligent segments using, among others, expert system tools. To verify effectiveness, the shop-floor scheduling system of a large-scale shipbuilding yard has been redesigned, developed, and tested using this approach. This shop-floor scheduling system requires the scheduling of when and where to process block construction under various constraints. It is a difficult four-dimensional time and space allocation problem involving traditional NP-complete search spaces. The tested intelligent agent system proposes an innovative method for reducing the search space into three levels: the algorithm level, the agent intelligence level, and the level of cooperation among agents. It also provides methods for solving deadlock occurrence and non-uniformity problems resulting from parallel processing. Test results demonstrate applicability and economy, among other technical advantages. 相似文献
7.
Gyudong Kim Min-Kyu Kim Byoung-Soo Chang Wonchan Kim 《Solid-State Circuits, IEEE Journal of》1996,31(7):966-971
A low-voltage, low-power CMOS delay element is proposed. With a unit CMOS inverter load, a delay from 2.6 ns to 76.3 ms is achieved in 0.8 μm CMOS technology. Based on a CMOS thyristor concept, the delay value of the proposed element can be varied over a wide range by a control current. The inherent advantage of a CMOS thyristor in low voltage domains enables this delay element to work down to the supply voltage of 1 V while the threshold voltage of the nMOS and pMOS transistors are 840 mV and -770 mV, respectively. The designed delay value is less sensitive to supply voltage and temperature variation than RC-based or CMOS inverter-based delay elements. Temperature compensation and jitter performance in a noisy environment are also discussed 相似文献
8.
基于本文第1部分的数学模型,求解了各种工艺参数下铸件/铸型间的界面热流和换热系数,重点研究不同工艺参数对于界面热流和换热系数的影响.在现有的"阶梯"块铸件的条件下,计算结果表明:压铸过程各种工艺参数对于铸件/铸型界面热流和换热系数有着不同的影响规律.铸型初始模腔表面温度对于界面热流的峰值有着很大的影响,随着铸型初始模腔表面温度的上升,热流峰值不断下降.对于较厚的"阶梯"面,铸型初始模腔表面温度对于界面换热系数的影响较大,随着该温度的上升,界面换热系数的峰值不断下降;对于较薄的"阶梯"面,各种工艺参数对于界面换热系数的影响不大. 相似文献
9.
Although milling is one of the most common chip metal removal processes, little has been done to aid in identifying the optimum operational conditions for milling processes. In this paper, a mathematical model for milling operations is developed and the five primary control variables identified. The model is then decomposed and an efficient optimization procedure developed for control variable identification. 相似文献
10.