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超幂零根环类的另一种模刻划
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作者 盖功琪 《哈尔滨师范大学自然科学学报》 1995年第4期28-31,共4页
本文对Szasz,F.A提出的"找出超幕零根环类的一个模刻划"问题[1]给出了一个不同于文献[2,3]的解法。
关键词 半质模 弱特殊 超幂零根环 结合环
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Modeling of Mass Transfer in Cavity Limited by a Semi Permeable Membrane (Simulation of Spiral Wound Module) 被引量:1
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作者 J. Ben Nacib R. Chouikh S. Bouguecha 《Journal of Environmental Science and Engineering》 2011年第5期567-573,共7页
The reverse osmosis process has been applied in large industrial fields (water treatment, food industry, biotechnology, and ect.). Despite, this progress more investigation are required to optimize the reverse osmos... The reverse osmosis process has been applied in large industrial fields (water treatment, food industry, biotechnology, and ect.). Despite, this progress more investigation are required to optimize the reverse osmosis process. The present paper deals the modeling of mass transfer in a cavity limited by a semi-permeable membrane. Mass conservation and momentum balances are developed, dimensionless and control volume method has been applied. The velocity and concentration profiles versus the Reynolds number and Sherwood are studied. The results show that the permeability of the membrane decreases as function of the transversal (radial) component of the velocity. The axial (tangential) component of the velocity presents a good stability along the thickness of the cavity; this phenomenon can be attributed to the zero gradient of the tangential velocity. These preliminary results show that the phenomenon of the concentration polarization affects the mass transfer coefficient in a channel. Current study has considered the cavity without a promoter of the turbulence; whereas, the design of the spacer has an important role on mass transfer coefficient in the reverse osmosis module. Our next interest is the integration of the spacer in the cavity, and the study of the effect of its design on the concentration and velocity profiles and the mass transfer coefficient through the reverse osmosis membrane. 展开更多
关键词 Membrane processes reverse osmosis spiral module modeling of mass transfer in a cavity (channel).
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Average Bond Energy and Fermi Level on Free Electronic Band Model
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作者 ZHENGYongmei WANGRenzhi 《Semiconductor Photonics and Technology》 CAS 1999年第1期9-13,共5页
On the basis of free-electronic bands, the Fermi energy is calculated by summing the band eigenvalues over Brillouin-zones ,and the results may lead to understand the physical basis of the average-bond-energy model in... On the basis of free-electronic bands, the Fermi energy is calculated by summing the band eigenvalues over Brillouin-zones ,and the results may lead to understand the physical basis of the average-bond-energy model in the calculation of valence-band offsets. 展开更多
关键词 Average Bond Energy Fermi Level HETEROJUNCTION
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Temperature dependence of the point defect properties of GaN thin films studied by terahertz time-domain spectroscopy 被引量:6
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作者 FANG HeNan ZHANG Rong +10 位作者 LIU Bin LI YeCao FU DeYi LI Yi XIE ZiLi ZHUANG Zhe ZHENG YouDou WU JingBo JIN BiaoBing CHEN Jian WU PeiHeng 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第11期2059-2064,共6页
The dielectric functions of GaN for the temperature and frequency ranges of 10–300 K and 0.3–1 THz are obtained using terahertz time-domain spectroscopy.It is found that there are oscillations of the dielectric func... The dielectric functions of GaN for the temperature and frequency ranges of 10–300 K and 0.3–1 THz are obtained using terahertz time-domain spectroscopy.It is found that there are oscillations of the dielectric functions at various temperatures.Physically,the oscillation behavior is attributed to the resonance states of the point defects in the material.Furthermore,the dielectric functions are well fitted by the combination of the simple Drude model together with the classical damped oscillator model.According to the values of the fitting parameters,the concentration and electron lifetime of the point defects for various temperatures are determined,and the temperature dependences of them are in accordance with the previously reported result.Therefore,terahertz time-domain spectroscopy can be considered as a promising technique for investigating the relevant characteristics of the point defects in semiconductor materials. 展开更多
关键词 THz time-domain spectroscopy GaN film temperature dependence
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Piezotronic transistors in nonlinear circuit:Model and simulation
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作者 HU GongWei ZHANG YuJing +3 位作者 LUO Lu YANG Yang ZHANG Yan WANG ZhongLin 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第8期1348-1354,共7页
For the materials that simultaneously exhibit piezoelectric and semiconductor properties,such as wurtzite Zn O,Ga N and In N,as well as two-dimensional single Mo S2,piezoelectric charges induced by externally applied ... For the materials that simultaneously exhibit piezoelectric and semiconductor properties,such as wurtzite Zn O,Ga N and In N,as well as two-dimensional single Mo S2,piezoelectric charges induced by externally applied strain can tune/control carrier transport at a metal-semiconductor contact or semiconductor junction,which is named piezotronic effect.Metal-semiconductor-metal piezotronic transistors are key piezotronic nanodevices for electromechanical applications,and they are typical nonlinear elements.In this paper,a simplified current-voltage analysis solution of piezotronic transistors is developed,which can be used for circuit design and simulation.Furthermore,the typical nonlinear circuit:Chua's circuit based on piezotronic transistors is simulated.We find that the output signal of the piezotronic transistor circuit can be switched and changed asymmetrically by externally applied strain.This study provides insight into the nonlinear properties of the piezotronic transistor,as well as guidance for piezotronic transistor nonlinear circuit application. 展开更多
关键词 piezotronic transistor nonlinear nanodevice electromechanical application nonlinear circuit
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