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   385篇
  免费   4篇
  国内免费   22篇
电工技术   5篇
综合类   11篇
化学工业   91篇
金属工艺   82篇
机械仪表   7篇
建筑科学   5篇
矿业工程   5篇
能源动力   43篇
轻工业   1篇
石油天然气   4篇
武器工业   4篇
无线电   62篇
一般工业技术   65篇
冶金工业   17篇
原子能技术   2篇
自动化技术   7篇
  2023年   5篇
  2022年   2篇
  2021年   6篇
  2020年   4篇
  2019年   3篇
  2018年   6篇
  2017年   8篇
  2016年   5篇
  2015年   10篇
  2014年   8篇
  2013年   18篇
  2012年   12篇
  2011年   43篇
  2010年   16篇
  2009年   26篇
  2008年   36篇
  2007年   26篇
  2006年   28篇
  2005年   17篇
  2004年   19篇
  2003年   18篇
  2002年   23篇
  2001年   10篇
  2000年   9篇
  1999年   4篇
  1998年   10篇
  1997年   8篇
  1996年   7篇
  1995年   3篇
  1994年   5篇
  1993年   3篇
  1991年   1篇
  1990年   4篇
  1989年   5篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
排序方式: 共有411条查询结果,搜索用时 203 毫秒
31.
Current work presents the first report on the modification of zirconia (ZrO2) by doping it with the lanthanides oxides i.e. [samarium, europium, and thulium] forming a [Sm/Eu/Tm] co-doped ZrO2 system. Lanthanide doping tailored the structure of host material by causing considerable bandgap energy shrinkage from 4.04 to 3.57 eV and reduction in the crystallite size from 67.92 to 45.23 nm. Profound electro-catalytic potential was reflected analyzed via linear sweep voltammetry showing the excellent of developed catalytic towards H2 evolution with lower overpotential i.e. 133 mV and Tafel slope of 119.3 mV dec−1. While for O2 evolution, the electro-catalyst succeeded in gaining overpotential and Tafel slope values of 310 mV and 294.8 mV dec−1, respectively. With such values, this material has surpassed the conventional electro-catalysts and is proved to be an excellent hydrogen producing electro-catalyst. The electrical charge storage potential was analyzed for [Sm/Eu/Tm] co-doped ZrO2 decorated nickel foam electrode for development into a super-capacitor. This electrode was impressively stable for 10 cycles after 20 days checked through cyclic voltammetry. Furthermore, an augmented specific capacitance of 447 F g−1 was achieved by the doped electrode when compared with the pristine one approaching 83.69 F g−1. The electrical energy storage capacity of [Sm/Eu/Tm] co-doped ZrO2 is even higher than the conventionally used metal oxides. In terms of the interfacial electrode-electrolyte, electrochemical impedance spectroscopy was done expressing the excellent ionic diffusion and electrochemically active sites for [Sm/Eu/Tm] co-doped ZrO2 electrode with minimal resistance. The developed doped system was used a spacer layer in a cesium lead halide perovskite solar cells having planar architecture. The spacer layer containing solar cell device succeeded in gaining a power conversion efficiency of 16.31% and a fill factor of 78% evaluated via photo-current measurements carried out under artificial solar irradiance. The impressively higher fill factor shows the effective passivation and scaffolding by the [Sm/Eu/Tm] co-doped ZrO2. The associated device was also marked by negligible hysteresis. Chrono-potentiometry and chrono-amperometry expressed commendable accelerated service lives for 100 min inside an electrolyte. The lanthanide co-doped ZrO2 is an effective material for the utilization in energy systems associated with the electro-catalysis of water, charge storage electrode for super-capacitors, and photovoltaic solar to electrical energy conversion.  相似文献   
32.
电镀锡板在生产和存储过程中表面易产生黑灰缺陷,其对镀锡板的涂饰性、耐蚀性、美观性等均造成不利的影响。分析了电镀锡工艺、镀液杂质离子、锡泥、软熔、电解钝化等因素对电镀锡板表面黑灰程度的影响,综述了国内镀锡板黑灰的相关研究。讨论了黑灰缺陷对镀锡板涂饰性的影响。  相似文献   
33.
Different polycrystalline silicon and single-crystalline silicon with dislocations were used for passivation and gettering processes. These materials have defects and more impurity in the crystal. The dominant increase of electronic performance was found for wafers with more defects by using a different casting method. The wafers of single crystalline silicon with dislocations also have higher increase of efficiency of cell in comparison with that wafer without dislocations during oxide passivation processes used. POCl3 was used for gettering processes. Single-crystal wafer with or without dislocations was used for comparison of gettering.  相似文献   
34.
The electrochemical properties of several types of diamond electrodes, including polycrystalline and homoepitaxial films, that underwent anodic treatment were examined with the electrochemical impedance spectroscopic (EIS) technique, as well as with capacitance-potential measurements. From an analysis of the impedance behavior, it was found that an additional capacitance element, which is apparent in the relatively high-frequency range (100-1000 Hz), was generated on the polycrystalline and (1 0 0) homoepitaxial diamond electrodes after anodic treatment. This capacitive element can be characterized as being non-Faradaic, because it has negligible dependence on the applied potential. Acceptor densities and depth profiles were calculated from the Mott-Schottky plots, and the acceptor densities in the near-surface region of the anodically treated surfaces were found to be extremely low. These results indicate that passive layers were generated on the diamond surfaces by the anodic treatment. The capacitance-potential behavior was also consistent with a model consisting of a semiconductor with a passive surface film. The passive film is proposed to arise as a result of the removal of hydrogen acting as an acceptor in the subsurface region, leaving hydrogen that is paired essentially quantitatively with the boron dopant, effectively neutralizing it.  相似文献   
35.
孙力军  季万涛 《半导体光电》1997,18(4):257-260,270
介绍了一种多路混合信号光纤传输系统。该系统采用单片机完成信号采集、正理3和传输,大大简人了硬件电路、缩小了产品体积,提高了系统的可靠性。  相似文献   
36.
报道了以正硅酸乙酯(TEOS)为源,采用等离子体增强化学汽相淀积(PECVD)技术在InP表面低温生长SiO2钝化膜。对SiO2/InP界面态进行了X射线光谱(XPS)分析和C-V特性研究。  相似文献   
37.
Microcircuit package qualification testing is used to establish the reliability of integrated circuit processes and devices as they relate to part packaging. This paper presents the results of package qualification tests conducted on plastic encapsulated microcircuits (PEMs) and plastic discrete devices (diodes, transistors) used in avionics applications. Highly accelerated stress test (HAST) and temperature cycle (TC) test results, including part failure mechanisms and associated failure rates, are provided. A variety of plastic package styles and integrated circuit functions have been tested. Examples of package styles tested include small outline (SO), plastic leaded chip carrier (PLCC), thin small outline package (TSOP), plastic quad flat package (PQFP) and plastic dual-in-line (PDIP).Manufacturers' devices have been evaluated and various plastic compounds have been compared to determine which provide optimum reliability. The testing showed that package qualification performance of PEMs is affected by type of compound, passivation (including die coat) and die size. HAST failures are caused by moisture penetration of the package while temperature cycle failures result from coefficient of thermal expansion (CTE) mismatch effects.  相似文献   
38.
This work intends to compare two different passivation methods for electromagnetically continuous pulling silicon (EMCP): remote plasma hydrogenation and remote plasma enhanced CVD of SiN followed by high-temperature sintering. All experiments are carried out on textured and non-textured EMCP samples from the same ingot. To check the effect of high-temperature diffusion on EMCP, a n+-emitter is formed on one group of the samples using POCl3 diffusion. Passivation capabilities of both techniques are checked using measurements of minority carrier lifetime by means of microwave photoconductance decay mapping. Solar cells are made to compare lifetime measurement with cell parameters.  相似文献   
39.
It is shown by contactless transient photoconductivity measurements in the microwave frequency range that Si3N4 films are an outstanding passivation of the n-type c-Si surface. Si3N4 on n-type Si forms an accumulation layer, which acts as an ideally reflecting potential barrier for minority carriers (holes). Due to the small space charge layer capacitance, minority carrier storage at this interface is very limited.In contrast to the latter measurements on p-type Si wafers covered with Si3N4 are characterized by storage of excess charge carriers in the surface depletion layer. The stored charge carriers decay slowly. The minority carriers (electrons) collected at the surface show a reduced mobility.  相似文献   
40.
From the point of view of waste recycling, hydroxyapatite (HAp) can be synthesized using the waste sludge from semiconductor process. The possibility of using HAp as an anticorrosive pigment was investigated. The water absorption of coating pigmented with anticorrosive pigment, HAp, red lead (RL) and zinc potassium chromate (ZPC), and the corrosion at interface between coating and substrate were monitored using AC impedance technique. The amount of absorbed water decreased in the order of ZPC- > HAp- > RL-pigmented > unpigmented film. However, the water absorbed into HAp- or ZPC-pigmented film seems to be beneficial to anticorrosive function. The anticorrosive performance of HAp is superior or at least comparable to those of ZPC and RL, which have been known as representative anticorrosive pigments. It seems that the anticorrosive properties of HAp is mainly achieved by passivating the substrate, namely the soluble component of HAp reacts with Fe to form iron phosphate in the presence of water.  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