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951.
《Mathematical Methods in the Applied Sciences》2018,41(13):5015-5049
In this paper, we consider the incompressible combined viscosity and magnetic diffusion magnetohydrodynamic system with Dirichlet boundary condition in a half space of . We establish the asymptotic expansions of this system by multiscale analysis and obtain the horizontal alone viscosity and magnetic diffusion magnetohydrodynamic equations and the boundary layer equations. And then we study the well‐posedness of the 2 equations. At last, we get the vanishing limit when the vertical viscosity and magnetic diffusion coefficient tends to zero. 相似文献
952.
《Mathematical Methods in the Applied Sciences》2018,41(8):3044-3061
In this paper, we consider the 2D Boussinesq system with variable kinematic viscosity in the velocity equation and with weak damping effect to instead of the regularity effect for the thermal conductivity. Even if without thermal diffusion in the temperature equation, we establish the global well‐posedness for the 2D Boussinesq system with general initial data. 相似文献
953.
954.
三氟碘甲烷的新气相状态方程和输运物性 总被引:2,自引:0,他引:2
提出了三氟碘甲烷(CF3I)的新蒸气压方程和新状态方程;给出了CF3I的偏心因子、正常沸点等物性参数,并与文献值进行了比较.使用毛细管粘度计测量了CF3I的253~338K的饱和液粘度,采用以钽丝为热线的双线瞬态热线法测量了CF3I的气相导热系数,并分别给出了关联式. 相似文献
955.
Variable responses are fundamental for all experiments, and they can consist of information-rich, redundant, and low signal intensities. A dataset can consist of a collection of variable responses over multiple classes or groups. Usually some of the variables are removed in a dataset that contain very little information. Sometimes all the variables are used in the data analysis phase. It is common practice to discriminate between two distributions of data; however, there is no formal algorithm to arrive at a degree of separation (DS) between two distributions of data. The DS is defined herein as the average of the sum of the areas from the probability density functions (PDFs) of A and B that contain a ≥ percentage of A and/or B. Thus, DS90 is the average of the sum of the PDF areas of A and B that contain ≥90% of A and/or B. To arrive at a DS value, two synthesized PDFs or very large experimental datasets are required. Experimentally it is common practice to generate relatively small datasets. Therefore, the challenge was to find a statistical parameter that can be used on small datasets to estimate and highly correlate with the DS90 parameter. Established statistical methods include the overlap area of the two data distribution profiles, Welch’s t-test, Kolmogorov–Smirnov (K–S) test, Mann–Whitney–Wilcoxon test, and the area under the receiver operating characteristics (ROC) curve (AUC). The area between the ROC curve and diagonal (ACD) and the length of the ROC curve (LROC) are introduced. The established, ACD, and LROC methods were correlated to the DS90 when applied on many pairs of synthesized PDFs. The LROC method provided the best linear correlation with, and estimation of, the DS90. The estimated DS90 from the LROC (DS90–LROC) is applied to a database, as an example, of three Italian wines consisting of thirteen variable responses for variable ranking consideration. An important highlight of the DS90–LROC method is utilizing the LROC curve methodology to test all variables one-at-a-time with all pairs of classes in a dataset. 相似文献
956.
刘艳红 《数学物理学报(B辑英文版)》2010,30(1):47-54
We investigate the decay rates of the planar viscous rarefaction wave of the initial-boundary value problem to scalar conservation law with degenerate viscosity in several dimensions on the half-line space, where the corresponding one-dimensional problem admits the rarefaction wave as an asymptotic state. The analysis is based on the standard L2-energy method and L1-estimate. 相似文献
957.
Xuan Ding Ye Chen Shenghui Chen Jun Li Xiaofeng Wang Huaping Wang 《Journal of Macromolecular Science: Physics》2013,52(6):1199-1207
A series of aromatic polysulfonamides with various monomer ratios of 4,4′-diaminodiphenylsulfone (p-DDS) and 3,3′-diaminodiphenylsulfone (m-DDS) were synthesized to investigate the relationship between copolymer composition and their properties. The copolymer composition was determined from nuclear magnetic resonance (NMR). It was found that the copolymer composition of the polysulfonamides varied little from the monomer ratio; thus, similar reactivity of the two diaminodiphenylsulfones was shown by the results. From the analysis of the thermal properties of the polysulfonamides, high thermal stability of the copolymers was shown both in N2 and air and the decomposition temperature exhibited little dependence on the copolymer composition. However, the glass transition temperatures (Tg ) decreased obviously with increasing m-DDS segments, which is helpful to improve the solubility and spinnability of these polysulfonamides. 相似文献
958.
本文提出一种基于扩张原理的ETSK(ExtendedTSK)模型,导出了该模型的输入输出解析式,给出了辨识这种模型的方法。本文还导出了ETSK模型的一种等价形式——变权TSK模型,从而将ETSK模型规则后件中的模糊数及其扩展运算转化为普通数的运算,使基于ETSK模型的模糊控制算法MBFC(Model-BasedFuzzyControl)易于实现。仿真辨识结果表明,ETSK模型的辨识效果和预报精度优于TSK和LM模型;MBFC算法的控制效果优于通常模型PI控制算法 相似文献
959.
960.
A. G. Zilman R. Granek 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,11(4):593-608
We consider a lamellar phase of bilayer membranes held between two parallel plates and subject to a steady shear. Accounting
for the coupling with the shear flow of the short wavelength undulation modes that are responsible for the membrane excess
area, we argue that the flow generates an effective force which acts to reduce the excess area. From the viewpoint of the
macroscopic lamellar whose geometric dimensions are fixed, this force translates into an effective lateral pressure. At low
shear rates this pressure is balanced by the elastic restoring forces of the lamellar. Above a critical shear rate , where d is the interlayer distance and D is the gap spacing, the lamellar buckles into a harmonic shape modulation, and we predict its wavelength and amplitude . We show that our model is isomorphic to a dilative strain, which is known to induce a similar buckling (undulation) instability.
Indeed, at threshold the wavelength is and is identical in both cases. Using a non-linear analysis, we discuss how the wavelength and amplitude vary with shear
rate away from the threshold. For we find and . We then focus on the coupling of the buckling modulation itself with the flow, and obtain a criterion for the limit of its
stability. Motivated by experiments of D. Roux and coworkers, we assume that at this limit of stability the lamellar breakups
into “onion"-like, multilamellar, vesicles. The critical shear rate for the formation of onions is predicted to scale as . The scaling with d is consistent with available experimental data.
Received 15 April 1998 and Received in final form 4 March 1999 相似文献