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1.
In this paper, we are concerned with the global existence and convergence rates of the smooth solutions for the compressible magnetohydrodynamic equations without heat conductivity, which is a hyperbolic-parabolic system. The global solutions are obtained by combining the local existence and a priori estimates if H3-norm of the initial perturbation around a constant states is small enough and its L1-norm is bounded. A priori decay-in-time estimates on the pressure, velocity and magnetic field are used to get the uniform bound of entropy. Moreover, the optimal convergence rates are also obtained. 相似文献
2.
In this article, the relationship between the Borel direction of algebroidal function and its coefficient functions is studied for the first time. To begin with, several theorems of algebroidal functions in unit disk are proved. By these theorems, some interesting conclusions are obtained. 相似文献
3.
We consider a branching random walk with a random environment in time, in which the offspring distribution of a particle of generation n and the distribution of the displacements of its children depend on an environment indexed by the time n. The environment is supposed to be independent and identically distributed. For AR, let Zn(A) be the number of particles of generation n located in A. We show central limit theorems for the counting measure Zn(·) with appropriate normalization. 相似文献
4.
The traditional model selection criterions try to make a balance between fitted error and model complexity. Assumptions on the distribution of the response or the noise, which may be misspecified, should be made before using the traditional ones. In this ar- ticle, we give a new model selection criterion, based on the assumption that noise term in the model is independent with explanatory variables, of minimizing the association strength between regression residuals and the response, with fewer assumptions. Maximal Information Coe~cient (MIC), a recently proposed dependence measure, captures a wide range of associ- ations, and gives almost the same score to different type of relationships with equal noise, so MIC is used to measure the association strength. Furthermore, partial maximal information coefficient (PMIC) is introduced to capture the association between two variables removing a third controlling random variable. In addition, the definition of general partial relationship is given. 相似文献
5.
Osteoporosis is a common clinical complication of post-menopausal women and the elderly and can significantly complicate the severity of bone fragility. The purpose of this study is to investigate how cod bone gelatin administration influences trabecular biomechanical properties after ovariectomy. Both biomechanical properties and trabecular microarchitectures were evaluated for cancellous bone samples from female ovariectomized rats, which were either shamoperated or treated with marine peptide(0.75, 1.5, 3.0, 6.0 g/kg body weight) for 90 days. The results have confirmed that cod bone gelatin treatment is effective in the prevention of mechanical property loss by preserving bone mass and trabecular architecture. 相似文献
6.
SU XinMing ZHANG JunHui WANG Jing BI YanQiang QIE DianFu XIANG ZhiHai XUE MingDe 《中国科学:物理学 力学 天文学(英文版)》2015,(4):63-71
Thermally induced vibration(TIV)is a typical failure of large-scale space structures.This paper reports a laboratory experiment that aims to investigate this unusual structural behavior of complex engineering structures.With the help of a Fourier finite element program,the fixing of a space boom section is well designed so that the TIV can be successfully observed.Although the observed torsional vibration mode is different from the bending vibration mode predicted by the classic theory based on a simple beam model,it can be successfully explained by the general thermal structural interaction theory.This demonstrates the validity of the theoretical model and the necessity of using finite element program to analyze complex engineering structures. 相似文献
7.
In this review, we briefly review recent works on hybrid(nano) opto-mechanical systems that contain both mechanical oscillators and diamond nitrogen-vacancy(NV) centers. We also review two different types of mechanical oscillators. The first one is a clamped mechanical oscillator, such as a cantilever, with a fixed frequency. The second one is an optically trapped nano-diamond with a built-in nitrogen-vacancy center. By coupling mechanical resonators with electron spins, we can use the spins to control the motion of mechanical oscillators. For the first setup, we discuss two different coupling mechanisms, which are magnetic coupling and strain induced coupling. We summarize their applications such as cooling the mechanical oscillator, generating entanglements between NV centers, squeezing spin ensembles etc. For the second setup, we discuss how to generate quantum superposition states with magnetic coupling, and realize matter wave interferometer. We will also review its applications as ultra-sensitive mass spectrometer. Finally, we discuss new coupling mechanisms and applications of the field. 相似文献
8.
Production mechanism of active species on the oxidative bromination following perhydrolase activity 下载免费PDF全文
Hypobromous acid and molecular bromine have been described as the active species involved in the oxidative bromination using perhydrolase, which catalyzes the reaction from acetic acid and hydrogen peroxide to peracetic acid (AcOOH). However, the brominating activity of them in a chemical model system was lower than that of the active species produced by the spontaneous reaction between AcOOH and Br?. Consequently, acetyl hypobromite (AcOBr) was suggested as new active species on the bromination by detection of the decarboxylation in the reaction between AcOOH and Br? and the strong brominating power with some tolerance against H2O2. Its production mechanism was explained as the ionic reaction involving the protonated intermediate of AcOOH by kinetic analysis. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
9.
ZHAN Ming-Jian LIU Xiao-Hui ZHANG Qi-Sheng WANG Bing-Xi CHENG Yan-Xiang LU Can-Zhong 《结构化学》2012,31(8):1145-1151
Four novel Cu(Ⅰ) complexes,[Cu(o-PYO)(PPh3)2]BF4(1),[Cu(o-PYO)(DPEphos)]BF4(2),[Cu2 (o-PYO)(PPh3)3(CH3CN)](BF4)2(3) and [Cu2(o-PYO)(DPEphos)2 ](BF4)2(4) (o-PYO=2,5bis(pyridyl)-1,3,4-oxadiazole,PPh 3=triphenylphosphine,DPEphos=bis(2-(diphenylphosphanyl)phenyl)ether),have been synthesized and characterized by 1 H NMR,elemental analysis and single-crystal X-ray diffraction.The central cuprous ions in all complexes are surrounded by N and P atoms to form a distorted tetrahedral geometry,although one of the cuprous ions in complex 3 is coordinated by a PPh3 and an acetonitrile molecule due to the steric hindrance and weak coordination ability from monodentate PPh3 ligand.The UV-vis absorption spectra in CH2Cl2 show the characteristic metal-to-ligand charge transfer (MLCT) absorption bands in the region of 360-480nm.Four Cu(I) complexes exhibit yellow to orange-red phosphorescence with the emission maximum at 572,577,562 and 597nm,respectively in the solid state. 相似文献
10.
Two compounds,3-oxo-N-o-tolylbenzo[d]isothiazole-2(3H)-carboxamide (1) and N-(2-methoxyphenyl)-3-oxobenzo[d]isothiazole-2(3H)-carboxamide (2),were synthesized from the initial compound benzo[d]isothiazol-3(2H)-one (BIT) and characterized by 1 H NMR,IR and elemental analysis,respectively.The single crystals of compounds 1 and 2 were obtained and determined by X-ray diffraction analysis.The preliminary results of biological activity experiment show that some of the title compounds exhibited a favorable antimicrobial activity. 相似文献