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   206篇
  免费   2篇
电工技术   5篇
化学工业   52篇
金属工艺   2篇
机械仪表   3篇
建筑科学   4篇
能源动力   1篇
轻工业   49篇
水利工程   1篇
无线电   12篇
一般工业技术   29篇
冶金工业   26篇
原子能技术   13篇
自动化技术   11篇
  2023年   1篇
  2022年   1篇
  2021年   5篇
  2020年   3篇
  2019年   3篇
  2017年   2篇
  2016年   1篇
  2015年   1篇
  2014年   4篇
  2013年   17篇
  2012年   6篇
  2011年   16篇
  2010年   6篇
  2009年   12篇
  2008年   17篇
  2007年   14篇
  2006年   9篇
  2005年   6篇
  2004年   6篇
  2003年   4篇
  2002年   9篇
  2001年   6篇
  2000年   5篇
  1998年   15篇
  1997年   6篇
  1996年   3篇
  1995年   5篇
  1994年   2篇
  1993年   4篇
  1992年   4篇
  1991年   2篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1982年   3篇
  1981年   1篇
  1980年   1篇
  1976年   1篇
排序方式: 共有208条查询结果,搜索用时 734 毫秒
51.
52.
ABSTRACT

Three electrical elements (i.e., resistance, capacitance, and relaxation frequency) of electrical double layer (EDL) formed around particles have been extracted by a measuring–fitting combination for a novel noninvasive online measurement technique of particle size and concentration in a liquid–particle mixture. The measuring–fitting combination means measuring the impedances with electrical-impedance spectroscopy (EIS) method, and fitting the equivalent circuit with Levenberg–Marquardt method. The liquid–particle mixture in the impedance measurement is made of sodium chloride solution and stainless particles; the equivalent circuit is established corresponding to the contents in the liquid–particle mixture. As a result, the influence of the particle size and concentration on the electrical elements in the EDL which are the resistance, capacitance, and relaxation frequency in the EDL are clarified and discussed. This method is useful for determination of the particle size and concentration in liquid–particle mixture.  相似文献   
53.
A method to detect mura, which is defined as an irregular lightness variation on a uniformly manufactured surface, is necessary to maintain the quality of the display devices. The mura is understood as defects without a clear contour or a contrast which imparts an unpleasant sensation to viewers. We propose a method to detect mura of the display devices’ components that have lower intensity than the final device with some background pattern considering the property of the human vision system.  相似文献   
54.
To identify proteins associated with esophageal carcinogenesis, we performed protein profiling of 16 esophageal squamous cell carcinomas (ESCCs) and paired noncancerous tissues by 2-DE and MS/MS. In cancerous tissues, three spots showed significant up-regulation in the amount of protein, while eight spots were significantly down-regulated. The identities of the spots were determined by PMF with LC-MS/MS and were confirmed by immunoblotting. The up-regulated proteins were tropomyosin alpha 4 chain, transgelin, and pyruvate kinase. The down-regulated proteins were serum albumin precursor, isoforms of annexin A1, tropomyosin beta chain, 14-3-3 protein sigma, and isoforms of serotransferrin precursor. In all 16 cases, up-regulation of the tropomyosin alpha 4 chain was confirmed by immunoblotting. Localization of the tropomyosin alpha 4 chain in ESCC cells and adjacent fibroblasts was confirmed by immunohistochemistry.  相似文献   
55.
Pituitary adenylate cyclase-activating polypeptide (PACAP) causes both Ca2+ release and Ca2+ influx in bovine adrenal chromaffin cells. To elucidate the mechanisms of PACAP-induced Ca2+ release, we investigated expression of PACAP receptors and measured inositol trisphosphates (IP3), cyclic AMP, and the intracellular Ca2+ concentration in bovine adrenal medullary cells maintained in primary culture. RT-PCR analysis revealed that bovine adrenal medullary cells express the PACAP receptor hop, which is known to couple with both IP3 and cyclic AMP pathways. The two naturally occurring forms of PACAP, PACAP38 and PACAP27, both increased cyclic AMP and IP3, and PACAP38 was more potent than PACAP27 in both effects. Despite the effects of PACAP on IP3 production, the Ca2+ release induced by PA-CAP38 or by PACAP27 was unaffected by cinnarizine, a blocker of IP3 channels. The potencies of the peptides to cause Ca2+ release in the presence of cinnarizine were similar. The Ca2+ release induced by PACAP38 or by PACAP27 was strongly inhibited by ryanodine and caffeine. In the presence of ryanodine and caffeine, PACAP38 was more potent than PACAP27. PACAP-induced Ca2+ release was unaffected by Rp-adenosine 3',5'-cyclic monophosphothioate, an inhibitor of protein kinase A. Ca2+ release induced by bradykinin and angiotensin II was also inhibited by ryanodine and caffeine, but unaffected by cinnarizine. Although IP3 production stimulated by PACAP38 or bradykinin was abolished by the phospholipase C inhibitor, U-73122, Ca2+ release in response to the peptides was unaffected by U-73122. These results suggest that PACAP induces Ca2+ release from ryanodine/caffeine stores through a novel intracellular mechanism independent of both IP3 and cyclic AMP and that the mechanism may be the common pathway through which peptides release Ca2+ in adrenal chromaffin cells.  相似文献   
56.
The computer codes PANAMA and FRESCO developed at the Research Center Jülich have been used for the prediction of fuel performance and fission product release behavior during the normal operation of the Japanese High-Temperature Engineering Test Reactor, HTTR. Basis for the calculations was the so-called ‘Standard HTTR Operation Plan’ with a nominal operation time of 660 efpd including a 110 efpd period with enhanced fuel temperatures. Fuel performance model calculations with the PANAMA code have shown that for the temperature distribution given, only a small additional failure fraction is expected. The diffusive release of metallic fission products from the fuel occurs mainly from the central core layers with the maximum temperatures whereas there is little contribution from the upper layer. Silver most easily escapes the fuel. The release data for strontium and cesium also reveal a significant fraction to originate from still intact particles. The comparison with the calculations obtained with the JAERI models has shown a good agreement for the release from the coated particles.  相似文献   
57.
Scan-based Design-for-Testability technique is widely used to enhance the testability. However, it increases the vulnerability to attacks through scan chains for secure chips such as cryptographic circuits with embedded secret keys. This paper proposes a secure scan design method which protects the circuits containing secret information such as cryptographic circuits from scan-based side channel attacks. The proposed method prevents the leakage of secret information by partial scan design based on a balanced structure. We also guarantee the testability of both the design under test and DFT circuitry, and therefore, realize both security and testability. Experiments for RSA circuit shows the effectiveness of the proposed method.  相似文献   
58.
We report analysis about generation data of a 100 kW PV system. The system consists of seven polycrystalline silicon arrays and three thin-film arrays. The rated power of each array is 10 kW. Thin-film is made of tandem structure comprising amorphous silicon and microcrystalline silicon. For each array, tilt angles are arranged in 10°, 20° or 30°. And directions are facing due south, south-south east 30° and south-south west 30°.We have been analyzing generation data of the system since 2007 to understand the influence of system arrangement. The knowledge we have got until now is below.
(a)
Seasonal annealing occurs in thin-film arrays because thin-film cells contain amorphous silicon. Thus, theoretically, as for reduction of conversion efficiency in high temperature season, reduction of thin-film arrays is smaller than polycrystalline’s. We analyzed the ratio of seasonal generation energy (kWh) by using measured data of the system. Generation energy ratio in summer of thin-film is larger than polycrystalline’s. This is same trend as the theory.
(b)
There is a simulated data of solar irradiation that had been calculated by using meteorological data of 30 years. According to this simulated data, optimum condition of the system is arranged in tilt angle of 28.4° and facing due south. (The system is situated at latitude 33° north.) And simulation data shows that yearly irradiation decreases as tilt angle and direction become far from optimum condition. We analyzed yearly generation energy of each array in the system. Each array’s reduction percentages of generated energy from optimum condition were smaller than simulation value.
  相似文献   
59.
In order to prepare the TiO2 liquid dispersions for the electrodes of dye-sensitized solar cells with industrial mass production level at a reasonable cost, the present study investigates the preparation of TiO2 liquid dispersions by a general industrial dispersion technique using readily available P25. To determine the TiO2 dispersion offering the best light–electricity energy conversion efficiency, the suitability of various types of solvents and resins for use in TiO2 dispersion are tested. In general, organic solvent based TiO2 dispersions are found to allow the formation of more uniform thin films in comparison with water-based dispersions. A preparation using ethyl cellulose as the resin and the terpineol as the solvent is found to exhibit the best conversion efficiency. We have also found that using two kinds of resins of different molecular weights gave rise to better efficiency. Among 26 metal compounds tested in this study, the best metal dopant was Ag. XRD and XPS measurements confirm that the Ag exists as metal Ag and silver oxide.  相似文献   
60.
To determine effects of high-pressure thawing on quality of high-pressure frozen tofu, kinu-tofu (soybean curd) was frozen 90 min at ca ?20°C at 100 MPa (ice I), 200 MPa (liquid phase), 340 MPa (ice III), 400, 500 or 600 MPa (ice V), then thawed at the same pressure. Texture and structure of this tofu (D) were compared with high-pressure-frozen tofu thawed at atmospheric pressure (A: 90 min frozen; B: 90 min frozen then 2 days at ?30°C; C: 160 min frozen). When tofu was frozen at 200- 500 MPa, ice crystals were largest to smallest in B > A and C > D; pore size of D was the same as untreated tofu. Results indicated ice crystals never grew when frozen at 200–500 MPa. Growth occurred during reduction of pressure at ca ?20°C, frozen storage or while thawing at atmospheric pressure due to phase transition.  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