首页 | 官方网站   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   144篇
  免费   3篇
工业技术   147篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2020年   1篇
  2019年   6篇
  2018年   3篇
  2017年   2篇
  2016年   4篇
  2015年   1篇
  2014年   3篇
  2013年   5篇
  2012年   4篇
  2011年   6篇
  2010年   5篇
  2009年   9篇
  2008年   8篇
  2007年   6篇
  2006年   4篇
  2005年   3篇
  2004年   4篇
  2003年   3篇
  2002年   4篇
  2001年   1篇
  2000年   4篇
  1998年   5篇
  1997年   3篇
  1996年   3篇
  1995年   1篇
  1994年   2篇
  1993年   5篇
  1992年   5篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1985年   2篇
  1984年   4篇
  1983年   3篇
  1982年   3篇
  1981年   2篇
  1980年   4篇
  1979年   4篇
  1978年   2篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1973年   2篇
  1971年   1篇
排序方式: 共有147条查询结果,搜索用时 257 毫秒
1.
In blockchain, full nodes (FNs) are peers that store and verify entire chains of transactions. In contrast, light clients (LCs) are those with limited resources, and for this reason, they request only block headers from FNs for transaction verification—using protocols like Simple Payment Verification (SPV). In an approach to prevent FN tampering on transaction verification (byzantine fault), LCs request block headers from multiple FNs and compare received responses. One problem with this approach is that an LC must connect to each FN and perform the same cryptographic operations with each one repeatedly, which leads to client‐side complexity and slower response. We propose an alternate approach to tackle this issue, in which LCs can encrypt a request for block headers only once, and send that request to a predetermined set of FNs to access, process, and reply back in a single response. Our approach, called Distributed Lightweight Client Protocol (DLCP), enables LCs to verify with little effort if FNs have agreed on a response. From an experimental evaluation, we observed that DLCP provided lower latency and reduced computing and communication overhead in comparison with the existing conventional approach.  相似文献   
2.
Prospects for redeveloping the older areas of cities for residential use depend largely upon the extent to which consumers prefer central rather than outlying locations for new housing. The strength of the downtown core, the regional transportation system, and the proximity of vacant land influence this preference. Empirical studies of new housing in three contrasting regions provide a means of evaluating the importance of these factors and their effects upon rents, densities, and vacancy rates at central and outlying locations.  相似文献   
3.
The anodic behavior of gold has been investigated in presence of chloride and/or water in 1-butyl-3-methylimidazolium methanesulfonate (BMI CH3SO3) ionic liquid (IL). The cyclic voltammetry (CVs) in presence of chloride ions shows two waves attributed to the oxidation of the gold electrode which occurs under two steps: the first one is attributed to the electrochemical dissolution of gold into to gold(I), while the second one is attributed to an overlap of the chloride oxidation step as well as the oxidation of Au(I) to Au(III). Furthermore the determination of water and chloride content in IL allowed observing that the passive layer induced by water could be removed under chloride. Thanks to those results we were able to clarify the conditions of gold recovering in this kind of electrolyte.  相似文献   
4.
We demonstrate the suitability of GeO2 for fibre engineering by compositional modifications of core and cladding glasses using the rod-in-tube technique, which have been matched for fibre drawing. The methods adopted for identifying the core–clad combination (56GeO2–31PbO–9Na2O–4Ga2O3 and 55GeO2–30PbO–11Na2O–4Ga2O3) are explained, based on the thermal, viscosity, and optical properties. We specially point out to the relatively high transformation temperature range (T> 380 °C) of the glass, which is suitable for chemical sensing and metrological applications in the 150–200 °C. The total intrinsic loss is compared with the measured loss in multi- and single-mode fibres from 0.532 to 2.02 μm, with loss less than 2.5 dB m−1 in the 1000–1600 nm range. The origin of larger loss outside this region is explained.  相似文献   
5.
We propose a novel metric ATEC for automatic MT evaluation based on explicit assessment of word choice and word order in an MT output in comparison to its reference translation(s), the two most fundamental factors in the construction of meaning for a sentence. The former is assessed by matching word forms at various linguistic levels, including surface form, stem, sound and sense, and further by weighing the informativeness of each word. The latter is quantified in term of the discordance of word position and word sequence between a translation candidate and its reference. In the evaluations using the MetricsMATR08 data set and the LDC MTC2 and MTC4 corpora, ATEC demonstrates an impressive positive correlation to human judgments at the segment level, highly comparable to the few state-of-the-art evaluation metrics.  相似文献   
6.
Alport syndrome is caused by mutations in collagen IV that alter the morphology of renal glomerular basement membrane. Mutations result in proteinuria, tubulointerstitial fibrosis, and renal failure but the pathogenic mechanisms are not fully understood. Using imaging mass spectrometry, we aimed to determine whether the spatial and/or temporal patterns of renal lipids are perturbed during the development of Alport syndrome in the mouse model. Our results show that most sulfatides are present at similar levels in both the wild-type (WT) and the Alport kidneys, with the exception of two specific sulfatide species, SulfoHex-Cer(d18:2/24:0) and SulfoHex-Cer(d18:2/16:0). In the Alport but not in WT kidneys, the levels of these species mirror the previously described abnormal laminin expression in Alport syndrome. The presence of these sulfatides in renal tubules but not in glomeruli suggests that this specific aberrant lipid pattern may be related to the development of tubulointerstitial fibrosis in Alport disease.  相似文献   
7.
The case has been established that the wind power plant must be treated as an integral part of the electric system, thereby constituting the wind energy conversion system. Recent advancement in size and technology of wind turbines requires sophisticated control systems to effectively optimize energy conversion and enhance grid integration. As a first step toward controller design, modelling has become a prerequisite. This paper explores controller design based on modelling the wind speed as a stochastic process, and the wind turbine as a multi‐mass system with a soft shaft linking the turbine with the doubly fed induction generator. A control strategy incorporating a linear quadratic Gaussian (LQG) that relies on state estimation for full‐state feedback is proposed to augment a linear controller for generator torque control. The control objectives are to reduce stresses on the drivetrain and to ensure operation geared toward optimal power conversion. This study focuses on above‐rated wind speeds, and the LQG's main purpose is to add damping to the drivetrain, thereby minimizing cyclic fatigue, while a pitch control mechanism prevents rotor overspeed, thereby maintaining rated power. Simulations show the efficacy of the proposed paradigm in meeting the control objectives. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
8.
Nowadays, a wind turbine generator (WTG) is required to provide control capabilities as the output power of WTG fluctuates. Under this scenario, this paper proposes an output power control method of a wind farm (WF) connected to a small power system using pitch angle control. In this control approach, the WF output power control is achieved by two control levels: central and local. In the central control, the WF output power command is determined by considering the frequency deviations and wind speeds using a fuzzy function. Then, the local output power commands for each of the WTGs are based on the proposed dispatch control. In the proposed dispatch control, the output commands of each WTG are determined by considering wind conditions for each of the WTGs. The simulation results by using an actual detailed model for the wind power system show the effectiveness of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
9.
在应用于化学加工、石油炼制、石油化工和基础重工业生产的众多工业气体过滤的气固分离中,烧结金属过滤系统被证实是一种高效、可靠和经济的选择。叙述了工业应用的,特别是要求半固定过滤的在高温高压下腐蚀环境中应用的烧结金属粉末或者烧结金属纤维过滤器的优点,讨论了所选应用领域,包括流化催化裂化(FCC)和连续催化重整/脱硫(CCR)的过滤器的操作和性能。  相似文献   
10.
1枪身与枪架分解前,应先检查膛是否内有枪弹(航向照准器与前照准器的连接杆未装入) 2拧松枪架两侧的支耳座盖紧定手柄,以解脱支耳座盖对枪身耳轴的约束;抽出固定枪身后部的插销,可将枪身从枪架上卸下  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-23

京公网安备 11010802026262号