全文获取类型
收费全文 | 52篇 |
免费 | 1篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 3篇 |
机械仪表 | 1篇 |
能源动力 | 3篇 |
无线电 | 26篇 |
一般工业技术 | 2篇 |
冶金工业 | 7篇 |
原子能技术 | 1篇 |
自动化技术 | 9篇 |
出版年
2020年 | 1篇 |
2015年 | 1篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有53条查询结果,搜索用时 15 毫秒
1.
2.
The charge collection efficiency of CdZnTe radiation detectors with two different configurations: aSchottky diode detector and aresistive detector are compared. The average charge collection efficiencies for three different directions of irradiation (negative electrode,
positive electrode and perpendicular to the electric field) are calculated. The mobility-lifetime product of the CdZnTe substrates
is evaluated from the dependence of the measured spectra upon detector bias voltage. The measurement of the average charge
collection efficiency is based on monitoring the shift of the peak channel with bias voltage in an experimental setup which
is well calibrated. Two types of radiation are used:gamma photons from several radioactive sources andalpha particles from an241Am source. The models for the evaluation of mobility-lifetime product from the measured data for the two types of detector
configurations as well as for the two types of radiation sources, are compared and discussed. The CdZnTe (Zn = 10%) substrates
under study are obtained commercially and are grown by the high pressure Bridgeman method. The mobility-lifetime products
and specific resistivity of the two types of detectors are evaluated and compared. A lower resistivity material has a narrower
depletion region and behaves like a thinner detector thus exhibiting better collection efficiencies. Therefore, medium resistivity
material which is completely inadequate for resistive detectors can still yield high performance Schottky detectors. The preferred
direction of irradiation, i.e. from the negative electrode, is possible only in the case of n-type material which is reverse
biased by negative voltages applied to the Schottky gate. The mobility-lifetime products that are derived on both the resistive
detector (with specific resistivity of ≈1.1010 ω.cm) and the Schottky diode (with specific resistivity of ≈1.106 Ω.cm) are μnτn ≈-4.10−4 cm2V−1 and μpτp≅ 8.10−5 cm2V−1. 相似文献
3.
Oleogels from Glycerol‐Based Lyotropic Liquid Crystals: Phase Diagrams and Structural Characterization 下载免费PDF全文
Yael Cegla‐Nemirovsky Abraham Aserin Nissim Garti 《Journal of the American Oil Chemists' Society》2015,92(3):439-447
In the course of our studies on structured reverse lyotropic liquid crystals (LLC) as oleogels, a system was designed with the desired physical and rheology properties for cosmetic and pharmaceutical applications. The aqueous phase was partially replaced by glycerol to minimize bacteriological problems and obtain specific rheology characteristics. The constructed phase diagrams are based on ternary mixtures of glycerol monooleate (GMO), decane, water, and glycerol. The main lyotropic mesophase obtained in this study was reverse hexagonal derived from dilution line 8:2 (72 wt% GMO and 18 wt% decane) and 10 wt% water; or water:glycerol (wt ratios 3:1 and 1:1) mixture. It was found that heat‐cool fluctuation caused formation of new pseudo‐equilibrium structures with mesomorphic transformations to more fluid and less ordered mesostructures. Replacing up to 50 wt% of the water by glycerol significantly increases the gel phase region in the phase diagram, meaning more structural compositional options. The structural parameters were determined using cross‐polarized light microscopy (CPLM), differential scanning calorimeter (DSC), powder X‐ray diffraction (PXRD), and small angle X‐ray scattering (SAXS). Rheological measurements revealed viscoelastic properties of lyotropic liquid crystals with a decrease in the elasticity (G′), plasticity (G″), and complex viscosity (η*), as a function of increasing the glycerol content. 相似文献
4.
Nemirovsky Y. Zelniker I. Degani O. Sarusi G. 《Journal of microelectromechanical systems》2005,14(6):1253-1264
Magnetostatic actuators exhibit bistability similarly to the pull-in phenomena of electrostatic actuators. In this paper a methodology and model for the extraction of the magnetic Pull-In parameters of magnetostatic actuators are derived. The flux-controlled magnetostatic actuator is analyzed based on the energy representation and the magnetomotive force-controlled magnetostatic actuator is analyzed in the thermodynamic potential energy (or co-energy) representation. An algebraic equation, referred to as the magnetic Pull-In equation, for each of the two cases (flux-controlled and magnetomotive force-controlled actuators) is derived. By solving these Pull-In equations either analytically or numerically, the magnetic Pull-In parameters are obtained. Several case studies, covering displacement and torsion magnetic actuators, are presented and analyzed, illustrating the usefulness of the proposed methodology, its relative simplicity as well as the adaptability and practical usage in wide spectrum of magnetic actuators. [1425]. 相似文献
5.
A novel set-up for horizontal open-tube vapor transport epitaxy of Hg1−xCdxTe films is described. Mirror-like Hg1−xCdxTe epitaxial layers with thicknesses up to 40 Μm were grown and characterized. The growth temperature ranged from 380 to 550‡C,
with growth rates of the order of 0.5–7 Μm per hour. The concentration depth profiles and the optical and electrical properties
of relatively uniform films with x≈0.3–0.4 are reported. The process kinetics are studied. A simple model which takes into
account the reactions occurring at the boundaries of the epitaxial layer and the interdiffusion in the epilayer is presented
and discussed. The model fits the experimentally observed characteristics of the epitaxial growth process. A constant growth
rate leading to a linear dependence of film thickness upon deposition time y–yi=ks t is derived. The reaction rate constant k is given by ks=koe−Ea/kT with ko=0.18 cm-sec−1and the energy of activation Ea=1.12 eV. 相似文献
6.
Sand spots, attached to a copper ball surface by means of polyvinyl acetate adhesive and distributed over the surface with areal density that ranges between one spot per 1.18 cm2 (for low‐density spots) and one spot per 0.51 cm2 (for high‐density spots), serve as a temporary heat transfer enhancer during the quenching in liquid nitrogen. Highest heat flux densities, achieved during quenching, lie in the range 10.8 to 20.2 W/cm2, depending on the sand layer structure. Application of the temporary enhancer increases an amount of heat, evacuated by highly effective nucleate and transition boiling, by factor of 4.5 as compared with the bare sample. The process of sand layer preparation, data acquisition peculiarities, relationship between heat exchange efficiency and the spots areal density, along with sand grit size are discussed in this paper. 相似文献
7.
Noise measurements of the 1/f noise in PMOS and NMOS transistors for analog applications are reported under wide bias conditions ranging from subthreshold to saturation. Two “low noise” CMOS processes of 2 μm and 0.5 μm technologies are compared and it is found that the more advanced process, with 0.5 μm technology, exhibits significantly reduced 1/f noise, due to optimized processing. The input referred noise and the power spectral density (PSD) of the drain current 1/f noise are modeled in saturation as well as in subthreshold and are compared with the common empirical approaches such as the SPICE models. The results of this study are useful to the design and modeling of 1/f noise of CMOS analog circuits 相似文献
8.
Y. Nemirovsky G. Asa A. Ruzin J. Gorelik R. Sudharsanan 《Journal of Electronic Materials》1998,27(6):807-812
Systematic measurements of dark noise spectra of CdZnTe x- and γ-ray spectrometers, correlated with the dc I-V characteristics and detector technology, are reported. The dark noise of two
innovative CdZnTe spectrometer configurations are studied: metal-semiconductor-metal (MSM) resistive detectors with three
terminals as well as heterostructure PIN detectors with thermally evaporated n+ CdS and p+ ZnTe contacts, which are fabricated on high pressure Bridgman CdZnTe (Zn=10%) crystals. The two innovative CdZnTe spectrometer
configurations presented here exhibit very low dark (leakage) current. By reducing the dc value of the dark (leakage) current
below 1 nA, shot noise becomes the dominant noise mechanism and the contribution of 1/f noise becomes negligible. The use
of non-injecting contacts (evaporated gold) for the MSM detectors and the operation of the PIN detector in the reverse bias
mode prevent generation-recombination noise which becomes dominant with injecting contacts (for example MSM detectors with
evaporated indium and titanium contacts) or when operating the PIN detector in the forward bias mode. Surface leakage is reduced
by applying surface passivation but is eliminated only by using the three terminal MSM configuration which exhibits simple shot noise instead of the suppressed shot noise observed in the two terminal MSM spectrometers. The noise measurements are useful for optimizing detector technology. 相似文献
9.
D. Goren N. Amir E. Khanin G. Asa Y. Nemirovsky 《Solar Energy Materials & Solar Cells》1996,44(4):966
CdTe has unique advantages for space applications solar cells. Previous structures were not able to yield the full potential of single crystalline solar cells. The limitations of these structures are discussed. We then report a new structure that is being studied with numerical simulations and preliminary experimental results. The actual fabrication and characterization of the cells under study are discussed in detail. 相似文献
10.
Pull-in study of an electrostatic torsion microactuator 总被引:10,自引:0,他引:10
Degani O. Socher E. Lipson A. Lejtner T. Setter D.J. Kaldor S. Nemirovsky Y. 《Journal of microelectromechanical systems》1998,7(4):373-379
Pull-in study of an electrostatic microactuator is essential for making the electrostatic actuation more effective. In this paper, pull-in analysis is presented for an electrostatic torsion microactuator. The torsion microactuator can be used as a microtorsion mirror. A polynomial algebraic equation for the pull-in voltage and pull-in angle of a torsion microactuator is derived. Two types of microactuators fabricated using bulk micromachining are presented. Measurements done on the fabricated microactuators are reported, showing deviations within 1% error from the calculations 相似文献