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Nonlinear MHD Kelvin-Helmholtz (K-H) instability in a pipe is treated with the derivative expansion method in the present
paper. The linear stability problem was discussed in the past by Chandrasekhar (1961)[1] and Xu et al. (1981).[6]Nagano (1979)[3] discussed the nonlinear MHD K-H instability with infinite depth. He used the singular perturbation method and extrapolated
the obtained second order modifier of amplitude vs. frequency to seek the nonlinear effect on the instability growth rate
γ. However, in our view, such an extrapolation is inappropriate. Because when the instability sets in, the growth rates of
higher order terms on the right hand side of equations will exceed the corresponding secular producing terms, so the expansion
will still become meaningless even if the secular producing terms are eliminated. Mathematically speaking, it's impossible
to derive formula (39) when γ
0
2
is negative in Nagano's paper.[3]Moreover, even as early as γ
0
2
→ O+, the expansion becomes invalid because the 2nd order modifier γ2 (in his formula (56)) tends to infinity. This weakness is removed in this paper, and the result is extended to the case of
a pipe with finite depth.
Theproject is supported by the National Natural Science Foundation of China. 相似文献
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CHEN AQing SHAO QingYi WANG Li & DENG Feng School of New Energy Engineering Leshan Vocational & Technical College Leshan China Laboratory of Quantum Information Technology School of Physics Telecommunication Engineering South China Normal University Guangzhou 《中国科学:物理学 力学 天文学(英文版)》2011,(8)
We present a system study on the electronic structure and optical property of boron doped semiconducting graphene nanoribbons using the density functional theory. Energy band structure, density of states, deformation density, Mulliken popular and optical spectra are considered to show the special electronic structure of boron doped semiconducting graphene nanoribbons. The C—B bond form is discussed in detail. From our analysis it is concluded that the Fermi energy of boron doped semiconducting graphene nano... 相似文献
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TANG YouCheng LI Bin YANG JingChang CHU Wei & LUO ShiZhong School of Chemical-Engineering Sichuan University Chengdu China Sichuan Xinguang Silicon Technology Corporation Limited Leshan 《中国科学B辑(英文版)》2009,(2)
The calcium chloride used for adsorption separation of ammonia is promising for its large adsorptive capacity and lower desorption temperature,but difficult to develop because of the liable expansion,lump and chip in the adsorption/desorption process.Composite adsorbents made by monolayer dis-persion of calcium chloride onto carriers with high surface areas exhibit better adsorptive capacity and stability.Several models were developed to confirm the maximum monolayer dispersion capacity of calcium chloride ... 相似文献
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Only the electron and ion gases were taken into account in all previous theories of the positive column of intermediately-low-pressure
arc discharge with or without the longitudinal magnetic field, while the motion of neutral gas was neglected. In 1982, the
authors[1] presented a nonlinear theory of a positive column which indicated that the rotating velocities of neutral gas and ion gas
were nearly equal, and the motion of neutral gas could not be ignored. They further discussed the problem of validity of Bohm's
criterion. However, some of the parameters with which the computation was worked out in Ref. [1] were not correlated to the
initial discharge parameters. In the present paper, two integral relations are supplemented, so that a complete mathematical
formation of the problem is given. A convergent numerical solution is obtained by iteration and the solution of Ref. [1] turns
out to be the first iteration approximation. It is shown that both functions and parameters obtained by self-consistent solution
differ significantly from those obtained in the first iteration approximation. According to this paper the computation can
be conducted when the initial discharge parameters are given, so this method could have certain practical applications. 相似文献
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The organization of a scientific data-base system and a management system is outlined. The chemical engineering data base includes seven separate data bases. Examples of applications of the inorganic thermochemistry data base are given for the production of phase diagrams and simulation of the QSL method for lead smelting. Interfacing of the various units is discussed. 相似文献
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