全文获取类型
收费全文 | 103篇 |
免费 | 1篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 13篇 |
机械仪表 | 3篇 |
建筑科学 | 4篇 |
能源动力 | 20篇 |
轻工业 | 2篇 |
无线电 | 14篇 |
一般工业技术 | 37篇 |
冶金工业 | 3篇 |
自动化技术 | 7篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 6篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 7篇 |
2012年 | 11篇 |
2011年 | 7篇 |
2010年 | 4篇 |
2009年 | 1篇 |
2008年 | 5篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2000年 | 1篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有106条查询结果,搜索用时 828 毫秒
1.
Wireless Personal Communications - This paper considers half-duplex cooperative spectrum sharing scheme where both primary and secondary systems mutually cooperate with each other to exploit... 相似文献
2.
Nucleation kinetics during the growth of InxGa1−xN on a GaN substrate have been studied. The behavior of nonequilibrium between the InxGa1−xN and the GaN substrate has been analyzed, and hence, the expression derived for the stress-induced supercooling/superheating
has been numerically evaluated. The maximum amount of stress-induced supercooling is found to be 1.017 K at x=0.12. These
values are incorporated in the classical heterogeneous nucleation theory. Using the regular solution model, the interfacial
tension between the nucleus and substrate and, hence, the interfacial tension between nucleus and mother phase and thermodynamical
potential of the compounds have been calculated. The amount of driving force available for the nucleation has been determined
for different compositions and degrees of supercooling. It has been shown that the value of the interaction parameter of InN-GaN
plays a dominant role in nucleation and growth kinetics of InxGa1−xN on a GaN substrate. These values have been used to evaluate the nucleation parameters. It is shown that the nucleation barrier
for the formation of a InxGa1−xN nucleus on a GaN substrate is minimum in the range of x=0.12 to x=0.17, and it has been qualitatively proved that good quality
InxGa1−xN on GaN can be grown only in the range 0<x≤0.2. 相似文献
3.
O Senthil Kumar K Balkis Ameen S Soundeswaran T Rajasekharan R Dhanasekaran 《中国稀土学报(英文版)》2006,24(Z1)
ZnSe∶Mn nanocrystals were grown by chemical vapour transport method using the matrix of SiO2 aerogels. The cubic structure of the nanocrystals was confirmed by powder X-ray diffraction (XRD) and electron diffraction (ED) studies. The size of the crystals was observed using transmission electron microscope (TEM). The oxidation state of Mn in ZnSe nanocrystal was found using electron spin resonance (ESR) spectrum. The room temperature luminescence measurements show the peaks corresponding to both bandgap of the material and Mn in ZnSe. 相似文献
4.
Concentration profile and growth rate studies of In1 − x
Ga
x
P LPE by computer simulation technique
H. Rezagholipour Dizaji R. Dhanasekaran 《Journal of Materials Science: Materials in Electronics》1996,7(3):181-185
Numerical simulation has been used to construct the concentration profiles of Ga and P atoms in In-rich melt at successive equally spaced layers in front of an InGaP crystal growing under normal conditions of liquid phase epitaxy (LPE). The growth rate has been calculated using the concentration gradient at the interface. The composition and the thickness of the InGaP solid grown as a function of growth parameters, such as cooling rate, system temperature and time, have been studied. It is observed that the thickness grown depends on the cooling rate, whereas the solid composition is independent of the cooling rate. The theoretical findings of our model have been compared with experimentally reported values and the results are discussed in detail. 相似文献
5.
Experimental and computational analysis on guide vane losses of impulse turbine for wave energy conversion 总被引:1,自引:0,他引:1
This paper deals with the detailed flow analysis of impulse turbine with experimental and computed results for wave energy power conversion. Initially, several turbulence models have been used in two-dimensional (2-D) computational fluid dynamic (CFD) analysis to find a suitable model for this kind of slow speed unconventional turbine. Experiments have been conducted to validate the CFD results and also to analyze the aerodynamics at various stations of the turbine. The three-dimensional (3-D) CFD model with tip clearance has been generated to predict the internal flow and to understand the effect of tip clearance leakage flow on behavior of the turbine in design and off-design conditions. As a result, it is found from the 2-D results that the comparison between computed and experimental data is good, qualitatively and the turbulence model, standard k–ε can predict the experimental values reasonably well, especially the efficiency of the turbine. Experimental results reveal that the downstream guide vanes are more responsible for low efficiency of the turbine and it is measured that 21% average pressure is lost due to downstream guide vanes. It is proved from the 3-D CFD model with tip clearance that it can predict the experimental values quantitatively and qualitatively. Furthermore, it is estimated from the computed results that the efficiency of the turbine has been reduced about 4%, due to tip clearance leakage flow at higher flow coefficients. 相似文献
6.
Wireless Personal Communications - One of the applications of Sparse Linear Wireless Sensor Networks is environmental monitoring. In these networks, sensors are deployed in sensitive and strategic... 相似文献
7.
S. Dhanasekaran Aravind Vadiraj G. Balachandran M. Kamaraj 《Transactions of the Indian Institute of Metals》2010,63(5):779-785
Austempering of a ferrite-pearlitic grade of ductile iron was carried out to assess the potential use of the material for
crank shaft application reported. A commercial material was austempered at 340°C to realize the properties. The austempered
ductile iron gave good strength although the ductility values were lower. The material developed had complete ausferritric
structure free of pearlite. The various phase constitution and phase transformation associated with the treatment and during
mechanical deformation was examined. Using XRD analysis the volume fraction of the austenite in the matrix was estimated.
The various aspects of processing a commercial cast iron during ausetmpering, the phase transformation, microstructural evolution
have been examined along with the property of the material. The mechanical behaviour of the material and the scope for further
improvement is discussed. 相似文献
8.
P. Prabukanthan K. Asokan D.K. Avasthi R. Dhanasekaran 《Materials Science in Semiconductor Processing》2007,10(6):252-257
Single crystals of CuInTe2 (CIT) have been grown by the chemical vapor transport (CVT) technique using iodine as the transporting agent. CIT crystals were irradiated with 80 MeV Au8+ ions at room temperature at different fluences. The surface roughness was measured using an atomic force microscope (AFM). It was found to increase from 9.319 nm in the as-grown sample to 61.169 nm in the sample irradiated with a fluence of 1×1013 ions/cm2. The intensities of the X-ray diffraction peaks corresponding to the (112) and (004/200) planes of the irradiated sample decrease with respect to the fluences. The full-width at half-maximum (FWHM) of X-ray rocking curves was measured as a function of different ion fluences. The FWHW increases with increase of ions fluences. This is attributed to the irradiation-induced partial amorphization of the top surface of the CIT crystals. The fall in absorption coefficients with photon energy is sharper for as-grown samples than irradiated samples. The band gap value gradually decreases from 1.04 to 0.977 eV upon Au8+ ions’ irradiation with a fluence of 1×1013 ions/cm2. Photoluminescence (PL) measurements show a red shift compared to the as-grown CIT single crystals. The Raman modes of A1 (high) and E and/or B2 (LO) are observed at 123 and 173 cm−1 in as-grown CIT single crystals, respectively. As the ion fluence is increased, the Raman frequency increases and the curves broaden. The above observed features are related to the large electronic energy transfer of the Au beam to the CIT crystals. 相似文献
9.
Computational analysis of performance and flow investigation on wells turbine for wave energy conversion 总被引:1,自引:0,他引:1
Wells turbine is a self-rectifying airflow turbine capable of converting pneumatic power of the periodically reversing air stream in oscillating water column into mechanical energy. This paper reports the computational analysis on performance and aerodynamics of Wells turbine with the NACA 0021 constant chord blades. Studies have been made at various flow coefficients covering the entire range of flow coefficients over which the turbine is operable. The present computational model can predict the performance and aerodynamics of the turbine quantitatively and qualitatively. The model also predicted the flow coefficient at which the turbine stalls, with reasonable accuracy. 相似文献
10.
The performance of a simple n+p silicon solar cell at various illumination levels is analysed by a modified form of the Gummel and De Mari numerical algorithms. Effects of high doping, such as bandgap narrowing together with the correction to density of states are included. The effective recombination life time of the charge carriers due to both Shockley-Read-Hall recombination via traps and Auger recombination is taken into account. The base acceptor doping concentration is 1016 cm?3. The light concentration is varied from 1 to 200 AM1. The physical mechanisms of the device at various levels of illumination are discussed by determining the cell parameters, namely, saturation current density, short circuit current density, ideality factor and fill factor. The ideality factor which is close to 1 at low illumination suggests that the cell is controlled by diffusion-recombination processes. The high value of the ideality factor, which is very much greater than 1 but less than 2, at high-illumination is attributed to high-injection effect. The efficiency reaches a maximum around 100 AM1 and starts falling beyond that. This fall is due to the high-injection and the voltage drop in the base layer. The fill factor starts falling at high-illumination. 相似文献