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   269篇
  免费   13篇
  国内免费   1篇
电工技术   12篇
化学工业   71篇
金属工艺   8篇
机械仪表   11篇
建筑科学   4篇
能源动力   11篇
轻工业   18篇
无线电   17篇
一般工业技术   68篇
冶金工业   14篇
原子能技术   13篇
自动化技术   36篇
  2023年   3篇
  2022年   10篇
  2021年   16篇
  2020年   6篇
  2019年   5篇
  2018年   15篇
  2017年   8篇
  2016年   12篇
  2015年   9篇
  2014年   11篇
  2013年   30篇
  2012年   29篇
  2011年   37篇
  2010年   14篇
  2009年   15篇
  2008年   8篇
  2007年   9篇
  2006年   9篇
  2005年   6篇
  2004年   5篇
  2003年   2篇
  2002年   4篇
  2001年   1篇
  2000年   1篇
  1999年   4篇
  1998年   1篇
  1997年   3篇
  1996年   1篇
  1994年   1篇
  1993年   1篇
  1992年   2篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1974年   2篇
排序方式: 共有283条查询结果,搜索用时 78 毫秒
61.
This paper proposes optimal total planning for incinerator plants (IPs) in a typical urban area, which includes a method of determining the number of plants and the capacities of the IPs. Burnable municipal refuse is disposed of sanitarily by high‐temperature incineration at the IPs. At the same time, power generation from waste (PGW) is being performed at many IPs to recover energy. At present, the amount of energy generated by PGW is greater than that of wind power or photovoltaic power generation. However, PGW has a limited generation efficiency and low generation output due to the smaller capacity of IPs. To overcome the above weakness, highly efficient PGW is necessary with total integration and scaling up of IPs. Regarding total integration and scaling up, operation in larger areas is favorable from the point of view of refuse volume and collection. In the planning stage, both the cost of IPs and refuse collection, which is important for refuse disposal, should be taken into account comprehensively. Optimal total planing for IPs can be performed in two stages. First, the disposal capacity Gk of an IP versus the number of plants K is decided by constraints. Gk is about the same for all K because of maintenance and refuse collection, and is greater than 300 tons per day in steps of 100 tons per day. Gk should be decided not only by refuse volume but also by cessation of operation at plants due to maintenance or faults. Second, the cost of each value of K is calculated based on the construction and operating costs of the IPs, income from selling the energy of PGW, and refuse collection costs. Therefore, the value of K with the minimum cost is selected as the optimal number of IPs. A numerical simulation of an area with a population of 3 million indicates that the optimal plant number is 4. At present there are eight or nine IPs in cities of 3 million people. The above cost reduction effect will be about 15% from the present value. Considering the situation of aging IPs, a decreasing trend in refuse volume, and the stringent financial conditions of local governments, the proposed method is very effective and realistic.  相似文献   
62.
Composite film of carbon nanotube (CNT) and polytetrafluoroethylene (PTFE) was successfully formed by using their dispersion fluids. This CNT/PTFE composite film was electrically conductive in the range of 10 S cm−1. The proton exchange membrane fuel cell (PEMFC) was assembled with the stainless steel bipolar plate coated with the CNT/PTFE composite film. This coating decreased the contact resistance between the surface of the bipolar plate and the membrane electrode assemble (MEA). Therefore, the output power of the fuel cell increased by 1.6 times.  相似文献   
63.
This article proposes multiple self-organizing maps (SOMs) for control of a visuo-motor system that consists of a redundant manipulator and multiple cameras in an unstructured environment. The maps control the manipulator so that it reaches its end-effector at targets given in the camera images. The maps also make the manipulator take obstacle-free poses. Multiple cameras are introduced to avoid occlusions, and multiple SOMs are introduced to deal with multiple camera images. Some simulation results are shown.  相似文献   
64.
65.
66.
A first‐order phase transition in a bulk material is generally considered to arise at extended defects such as grain boundaries or dislocations, where the energetic barrier between the two phases is reduced. Downsizing a crystal to the nanoscale can exclude the number of defects, leading to enhanced kinetic stabilization of the metastable phase. Here, the disappearance of the first‐order metal–insulator transition in defect‐free V2O3 nanocrystals and the revival of the transition by introducing a certain Cr or Ti impurity content are investigated. The hysteresis width of the transition corresponding to the barrier height decreases with the impurity content. It is proposed that homogeneous impurity doping is a universal method that can control the occurrence of a first‐order phase transition in nanoscale materials.  相似文献   
67.
We have developed a two-step microextrusion technique to align lipid nanotubes of 200 nm in diameter in parallel on planar glass substrates. This technique is useful to align self-assembled molecular nanofibers or nanotubes with diameters ranging from 100 to 300 nm. In the first step, we applied relatively large air pressure (approximately 40 hPa) onto a microcapillary filled with aqueous dispersion of lipid nanotubes to push them out. An aqueous droplet with 60 microm diameter was then extruded from the tip of the microcapillary. After one end of the lipid nanotube moved out, we changed the air pressure to be smaller, approximately 20 hPa to reduce the flow rate of the dispersion. The decrease in size of the droplet allowed us to fix the exposed end of the lipid nanotube onto the planar substrate. By dragging the microcapillary along the planar surface, we were able to align the whole nanotube onto the substrate. Using this technique, we have achieved the parallel alignment of the lipid nanotubes on the glass substrate.  相似文献   
68.
We proposed the low temperature formation technique of strain-relaxed Si1 − x − yGexSny-on-insulator (SGTOI) structures. We found that the solid-phase reaction and the formation of single and uniform Si1 − x − yGexSny layer on an insulator after annealing SiO2/Ge1 − zSnz/SOI structures even at a temperature as low as 400 °C. We characterized the crystalline structure of SGTOI, and investigated the effects of annealing, Sn incorporation, and a SiO2 cap layer on the solid-phase reaction between Ge1 − zSnz and SOI layers. The solid-phase reaction is enhanced with a higher Sn content and a thicker SiO2 cap layer, and then Si1 − x − yGexSny layers are more rapidly formed. The SGTOI layer exhibits very low mosaicity and have good crystallinity.  相似文献   
69.
A new leak element using a sintered stainless steel filter with a pore size of less than 1 μm has been developed for in-situ calibrations of ionization gauges (IGs) and quadruple mass spectrometers (QMSs). The gas flow through this leak element realizes molecular flow at an upstream pressure of less than 104 Pa. This new leak element, which is a kind of open-type standard leak, has four advantages. (1) Calibrations for various gas species are available only with this single leak element because the conductance is easily compensated for gas species by molecular mass. (2) Calibrations with multiple pressure points are easily available because the conductance is constant against changing upstream pressure. (3) Calibrations for a gas mixture are available because the interference effect between gas molecules in a gas mixture is negligible. (4) The dependence of flow rate on temperature is small and is compensated theoretically. These advantages were experimentally demonstrated. The stability and uncertainty of the leak element were also evaluated. The changes in the conductance of this leak element were less than 3% over one year. Since the conductance is typically 10−10 · m3/s, the reference gas flow in the range from 10−8 Pa · m3/s to 10−6 Pa m3 is obtained by changing the upstream pressure from 102 Pa to 104 Pa with an uncertainty of approximately 6%.  相似文献   
70.
Using UV mutagenesis, 2 high-pressure (HP) sensitive (barosensitive) mutants of Saccharomyces cerevisiae were obtained. The HP inactivation of the mutants, as well as their parent strains, followed 1st-order kinetics in the range of 175 to 250 MPa within 600 s. Both mutants showed larger 1st-order inactivation rate constant values or significant loss of viabilities, compared with their parent strains in the pressure range tested. The inactivation rate constant value of one of the mutants was comparable with that of a previously reported highly barosensitive strain, which was generated by deletion of hsp104 in a trehalose deficient strain. The activation volume values of HP inactivation reactions in the 2 mutants were apparently equivalent with those of their parent strains. This suggested that the mutation did not bring drastic volume changes of the key molecules for HP inactivation. Their auxotrophic properties, growth, and ethanol fermentation were identical in mutant and parent strains. The mutants could therefore be useful for fermentations where control by HP processing is desired.  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