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   167篇
  免费   2篇
电工技术   1篇
化学工业   25篇
金属工艺   3篇
机械仪表   12篇
建筑科学   5篇
能源动力   5篇
轻工业   21篇
无线电   13篇
一般工业技术   32篇
冶金工业   18篇
原子能技术   2篇
自动化技术   32篇
  2023年   2篇
  2022年   5篇
  2021年   8篇
  2020年   10篇
  2019年   10篇
  2018年   10篇
  2017年   7篇
  2016年   10篇
  2015年   8篇
  2014年   13篇
  2013年   9篇
  2012年   8篇
  2011年   9篇
  2010年   5篇
  2009年   9篇
  2008年   7篇
  2007年   4篇
  2006年   4篇
  2005年   1篇
  2004年   2篇
  2003年   1篇
  2002年   1篇
  1999年   1篇
  1998年   4篇
  1997年   4篇
  1996年   2篇
  1995年   3篇
  1994年   2篇
  1993年   1篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1983年   2篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1975年   1篇
排序方式: 共有169条查询结果,搜索用时 417 毫秒
1.
Studies on odor mixture perception suggest that although odor components can often be identified in mixtures, mixtures can also give rise to novel perceptual qualities that are not present in the components. Using an olfactory habituation task, the authors evaluated how the perceptual similarity between components in a mixture affects the perceptual quality of the mixture itself. Rats perceived binary mixtures composed of similar components as different from their 2 components, whereas binary mixtures composed of dissimilar components were perceived as very similar to their components. Results show that for both types of mixtures, pretraining to Component A reduces subsequent learning about Component B in rats trained in the presence of A. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
2.
Navneet Rao 《电子设计应用》2007,(12):16-16,18,20,22,24,37
SRIO IP解决方案提供真实双向数据流,大大增强连接功能。目前,对高速通信与超快计算的需求正与日俱增。有线和无线通信标准的应用随处可见,数据处理架构每天都在扩展。较为普遍的有线通信方式是以太网(LAN、WAN和MAN网络)。手机通信是最为常见的无线通信方式,由应用了DSP的  相似文献   
3.
The absorption, fluorescence excitation and emission spectroscopy, and time‐dependent spectrofluorimetry have been used to study the photophysics of copolymers of N‐vinylcarbazole with different monomers like vinyl acetate, methyl acrylate, methyl methacrylate, butyl acrylate, and butyl methacrylate in dichloromethane. In all the copolymers and at different N‐vinylcarbazole content, the absorption spectra reflect only the monomer carbazole units. The two kinds of excited monomer species of N‐vinylcarbazole are present in S1 state. Short‐lived (~3 ns) excited monomer decays forming low energy excimer obtained by the complete overlap of the excited carbazole monomer. The long‐lived excited monomer (~8 ns) decays to ground state without formation of any excimer. The high energy excimer is relatively short‐lived and is formed by the partial overlap of the carbazole units. The presence of bulky group in the copolymer chain hinders the formation of excimers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 372–380, 2006  相似文献   
4.
The aim of this paper is to design a current source obtained as a representation of p information symbols \(\{I_k\}\) so that the electromagnetic (EM) field generated interacts with a quantum atomic system producing after a fixed duration T a unitary gate U(T) that is as close as possible to a given unitary gate \(U_g\). The design procedure involves calculating the EM field produced by \(\{I_k\}\) and hence the perturbing Hamiltonian produced by \(\{I_k\}\) finally resulting in the evolution operator produced by \(\{I_k\}\) up to cubic order based on the Dyson series expansion. The gate error energy is thus obtained as a cubic polynomial in \(\{I_k\}\) which is minimized using gravitational search algorithm. The signal to noise ratio (SNR) in the designed gate is higher as compared to that using quadratic Dyson series expansion. The SNR is calculated as the ratio of the Frobenius norm square of the desired gate to that of the desired gate error.  相似文献   
5.
6.
Image and video processing techniques are being frequently used in medical science applications. Computer vision-based systems have successfully replaced various manual medical processes such as analyzing physical and biomechanical parameters, physical examination of patients. These systems are gaining popularity because of their robustness and the objectivity they bring to various medical procedures. Hammersmith Infant Neurological Examinations (HINE) is a set of physical tests that are carried out on infants in the age group of 3–24 months with neurological disorders. However, these tests are graded through visual observations, which can be highly subjective. Therefore, computer vision-aided approach can be used to assist the experts in the grading process. In this paper, we present a method of automatic exercise classification through visual analysis of the HINE videos recorded at hospitals. We have used scale-invariant-feature-transform features to generate a bag-of-words from the image frames of the video sequences. Frequency of these visual words is then used to classify the video sequences using HMM. We also present a method of event segmentation in long videos containing more than two exercises. Event segmentation coupled with a classifier can help in automatic indexing of long and continuous video sequences of the HINE set. Our proposed framework is a step forward in the process of automation of HINE tests through computer vision-based methods. We conducted tests on a dataset comprising of 70 HINE video sequences. It has been found that the proposed method can successfully classify exercises with accuracy as high as 84%. The proposed work has direct applications in automatic or semiautomatic analysis of “vertical suspension” and “ventral suspension” tests of HINE. Though some of the critical tests such as “pulled-to-sit,” “lateral tilting,” or “adductor’s angle measurement” have already been addressed using image- and video-guided techniques, scopes are there for further improvement.  相似文献   
7.
We report investigations on polycrystalline LaCo1?x Al x O3 (x = 0–0.9) bulk samples. The solid state synthesized samples showed a coexistence of rhombohedral and monoclinic phases in the intermediate concentrations (0.2 ≤ x ≤ 0.5) and pure rhombohedral phase otherwise. The observed effect of Al doping on dc transport has been analysed on the basis of small polaron hopping mechanism. The magnetisation results presented give evidence of weak ferromagnetism and anomalous temperature dependence of coercivity which we associate to the canting of the localised high-spin Co(III) and anti-symmetric exchange interactions at low temperatures.  相似文献   
8.
The present study reports the preparation and application of a novel biopolymer-based composite hydrogel (BCH) for removal of synthetic dye rhodamine 6G (Rh6G). BCH was prepared from biopolymer chitosan and acrylic acid monomer, in the presence of initiator (K2S2O8) and cross-linker thiourea using microwave irradiation. Synthesized chitosan-based composite hydrogel was characterized by using analytical techniques including Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), derivative thermogravimetric analysis (DTA) and differential thermal analysis (DTG). The stability of the adsorbent was demonstrated from its water uptake capacity. The dynamics of water sorption study showed the Fickian behavior. The investigations were continued to assess the adsorption potential of BCH for removal of Rh6G from aqueous solution. The effect of process parameters affecting the adsorption of rhodamine 6G (Rh6G), such as adsorbent dose, initial concentration of pollutant, contact time and pH of the solution was evaluated. Removal efficiency of chitosan-based composite hydrogel (BCH) was found to be 87.31% at pH 7 for BCH dose of 1 g/L after 8 h. The obtained data were fitted to adsorption isotherms and kinetics models. The adsorption equilibrium isotherm and kinetics studies indicated that the pseudo-second-order model and the Freundlich model well described the adsorption equilibrium of Rh6G on BCH.  相似文献   
9.
This paper discusses stochastic analysis of the ash handling system in a thermal power plant. The system consists of four subsystems Ai, Bj, C and Dk in series, with three possible states: good, reduced and failed. Failure and repair rates for each subsystem are taken to be constants. Using a probabilistic approach, the differential equations are generated and the expression for steady state availability is computed. Taking data from the thermal power plant, situated in North India, the behaviour of each working unit is analysed. Problems and remedies with appropriate maintenance schedules have been discussed. The results are discussed with the plant personnel and are helpful to the management in predicting the behaviour of each operating unit, so that timely decisions can be taken for maintaining the system in upstate for a long duration.  相似文献   
10.
The present paper deals with a shop floor applicable mathematical model for deposition rate during twin-wire submerged arc welding. The salient features of this model are (1) instead of melting rate, as modeled during past investigations, it quantifies the deposition rate, which is the actual outcome of the process and always remains smaller than the melting rate because of evaporation or spatters losses and (2) it estimates electrode extension in order to predict the deposition rate which makes the proposed model more practical than the models constituted with the help of experimental measurement of electrode extension. The model is more scientific than the simplified models where contact tube to work-piece distance has been considered as the electrode extension. A critical review of the relevant past investigation is given and a mathematical model is developed for deposition rate during the twin-wire welding with both the polarities, i.e., direct current electrode positive and direct current electrode negative. The model is calibrated using the results of 200 experimental runs and it is found to be very accurate with very high coefficient of regression and admissible standard error. The developed model is further validated with extra experimental runs. The practicality of the considered approach for prediction of deposition rate can further be used in future research for other consumable arc welding processes.  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