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   236篇
  免费   11篇
电工技术   1篇
化学工业   31篇
金属工艺   3篇
机械仪表   3篇
建筑科学   3篇
能源动力   9篇
轻工业   64篇
石油天然气   1篇
无线电   26篇
一般工业技术   45篇
冶金工业   36篇
原子能技术   2篇
自动化技术   23篇
  2023年   5篇
  2022年   5篇
  2021年   17篇
  2020年   3篇
  2019年   5篇
  2018年   10篇
  2017年   7篇
  2016年   7篇
  2015年   5篇
  2014年   3篇
  2013年   20篇
  2012年   11篇
  2011年   13篇
  2010年   7篇
  2009年   5篇
  2008年   7篇
  2007年   17篇
  2006年   4篇
  2005年   4篇
  2004年   7篇
  2003年   3篇
  2002年   5篇
  2001年   4篇
  2000年   5篇
  1998年   13篇
  1997年   7篇
  1996年   6篇
  1995年   13篇
  1994年   6篇
  1993年   4篇
  1992年   2篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1985年   1篇
  1984年   2篇
  1981年   2篇
  1978年   2篇
  1976年   3篇
  1975年   1篇
  1972年   1篇
  1964年   1篇
排序方式: 共有247条查询结果,搜索用时 15 毫秒
1.
2.
The physicochemical and functional properties of convection oven- and freeze-dried gluten meals of two corn varieties were evaluated. The physicochemical properties (water solubility index, water absorption index, Hunter color parameters, and bulk density) and functional properties (water absorption, oil absorption, least gelation concentration, protein solubility, and emulsification properties) of convection-oven and freeze-dried corn gluten meals were compared with each other and soy flour. Freeze-dried corn gluten meals was observed to have lower bulk density (0.244-0.263 kg/m3) and was lighter in color (high L and ΔE) compared to their counterpart convection oven-dried gluten meals. Freeze-dried gluten meals from both corn varieties showed significantly higher oil absorption, water absorption, pH, emulsification, and protein solubility compared to oven-dried corn gluten meals. The gluten meals from both corn varieties had lower water absorption and bulk density but higher oil absorption than soy flour, suggesting the hydrophobic nature of corn proteins. Corn gluten meals formed thin (pourable) emulsions compared to soy flour emulsions, which were thick salad dressing type. Freeze- and convection oven-dried corn gluten meals showed significantly lower protein solubility measured at different pH than soy flour.  相似文献   
3.
The use of the finite element method for complex engineering problems is now common. To ease the burden on the engineer the development of smart or adaptive computational methods is now required to model complex problems. In this paper we investigate the development of an adaptive finite element method for fracture-related problems. The adaptive method involves various stages which include the finite element analysis, error estimation/indication, mesh refinement and fracture/failure analysis in a loop. Some simple error estimators, based on stress projection, are used to investigate the adaptive finite element process. Element refinement is based on three schemes; the first and second are a simple and hierarchical refinement scheme with transitioning which avoids the need for constraint equations between element boundaries. Another scheme based on constraint equations between elements is also examined. The energy norm is used to estimate the element error. The software has the ability to introduce a discrete fracture in the structure according to standard fracture analysis practice. Crack tip parameters are calculated using a least-squares fit of the displacements into the asymptotic crack tip displacement field. Some simple examples are used to investigate the adaptive process, its behavior and some of the practical problems encountered. The convergence and equilibrium of the adaptive process, in terms of global error in the energy norm, are investigated. In the example the same problem is analyzed using both a fine computational grid and a coarse one. The coarse mesh is then adapted using the three different procedures available. The estimated error in the solution and the stress intensity are shown against the number of elements and number of iterations. Some further areas of research in adaptive finite element analysis are discussed.  相似文献   
4.
5.
1. The effects of diethyl maleate (DEM) on the cytotoxicity of phenyl-hydroquinone (PHQ) and other hydroquinones were studied in freshly isolated rat hepatocytes. 2. Addition of PHQ (0.5 or 0.75 mM) to hepatocytes resulted in dose-dependent cell death accompanied by the abrupt depletion of both GSH and protein thiols and the accumulation of phenyl-benzoquinone (PBQ). 3. Pretreatment with DEM (1.25 mM), which causes an abrupt depletion of cellular GSH in hepatocytes, delayed the onset of PHQ-induced cytotoxicity. The delay correlated with inhibition of PBQ formation. 4. Although the pH of the cell suspension was increased slightly (mean pH 0.18) by incubation under carbogen flow, the addition of DEM to the cell suspension inhibited both the increase in pH and the formation of PBQ from PHQ. 5. In hepatocyte suspensions without DEM, PHQ cytotoxicity was dependent on pH, and toxicity was associated with oxidation of PHQ and accumulation of PBQ. 6. Among other hydroquinones (0.5 mM), tert-butyl-hydroquinone-induced cytotoxicity was decreased by DEM (1.25 mM), but DEM did not affect the cytotoxicity of 2,5-di(tert-butyl)-1,4-benzohydroquinone. 7. PHQ-induced cytotoxicity correlated with the accumulation of PBQ in the cell, and the inhibition of PHQ-induced cytotoxicity by DEM correlated with pH-dependent changes in PBQ formation.  相似文献   
6.
7.
Organofunctional silanes recently have emerged as outstanding, environmentally friendly corrosion protectors for metal substrates, compared with conventional chromate treatments. A simple immersion technique is typically used to coat the metal surface with silane films. However, the thickness and uniformity of the films are uncontrolled in this process. This paper proposes a new deposition technique for the silane films on the metal surface, i.e., by electrodeposition. Hydrolyzed silanes are water-soluble, ionized molecules, so they can be deposited on metals by electrodeposition. Various combinations of silane mixtures were tested at different voltages, pH values, bath concentrations, and exposure times on panels of alloy aluminum and mirror-polished ferro-plate. The surface structure was characterized by scanning electron microscopy (SEM) and ellipsometry. The resistance of the film to corrosion was investigated by direct current (DC) polarization and electrochemical impedance spectroscopy (EIS) techniques. Electrodeposition results in a more organized and uniform film with fewer pores, compared with immersed or dipped films. This paper was presented at the 2nd International Surface Engineering Congress sponsored by ASM International, on September 15–17, 2003, in Indianapolis, Indiana, and appears on pp. 320–26 of the Proceedings.  相似文献   
8.
In this paper, we address the problem of 2D–3D pose estimation. Specifically, we propose an approach to jointly track a rigid object in a 2D image sequence and to estimate its pose (position and orientation) in 3D space. We revisit a joint 2D segmentation/3D pose estimation technique, and then extend the framework by incorporating a particle filter to robustly track the object in a challenging environment, and by developing an occlusion detection and handling scheme to continuously track the object in the presence of occlusions. In particular, we focus on partial occlusions that prevent the tracker from extracting an exact region properties of the object, which plays a pivotal role for region-based tracking methods in maintaining the track. To this end, a dynamical choice of how to invoke the objective functional is performed online based on the degree of dependencies between predictions and measurements of the system in accordance with the degree of occlusion and the variation of the object’s pose. This scheme provides the robustness to deal with occlusions of an obstacle with different statistical properties from that of the object of interest. Experimental results demonstrate the practical applicability and robustness of the proposed method in several challenging scenarios.  相似文献   
9.
In this paper, a new approach for optimally sizing the storage system employing the battery banks for the suppression of the output power fluctuations generated in the hybrid photovoltaic/wind hybrid energy system. At first, a novel multiple averaging technique has been used to find the smoothing power that has to be supplied by the batteries for the different levels of smoothing of output power. Then the battery energy storage system is optimally sized using particle swarm optimization according to the level of smoothing power requirement, with the constraints of maintaining the battery state of charge and keeping the energy loss within the acceptable limits. Two different case studies have been presented for different locations and different sizes of the hybrid systems in this work. The results of the simulation studies and detailed discussions are presented at the end to portrait the effectiveness of the proposed method for sizing of the battery energy storage system. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
10.
Attenuated total reflectance–Fourier transform infrared spectroscopy, along with chemometrics, were used to detect and quantify soya bean oil (SO) and sugar (CS) adulteration in milk. Bovine milk was artificially adulterated with SO (0.2–2.0%; v/v) and CS (1–10%; w/v) separately. Spectra revealed significant differences in specific wavenumber regions (SO: 1450–1250 cm?1; CS: 1200–900 cm?1). Soya bean oil adulteration was best predicted in wavenumber range of 1262–1164 cm?1, using partial least square regression (coefficient of determination (R2: 0.90 and 0.88 for calibration and validation, respectively). Common sugar adulteration was best predicted in wavenumber range of 1010–910 cm?1 (R2: 0.99 for calibration and validation) using partial least square.  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