Ditzian—Totik型的Besov空间和Bernstein—Durrmeyer算子

对任一函数f∈L_p[0,1],n阶Bernstein—Durrnieyer算子为     

Pullback attractors for a non-autonomous incompressible non-Newtonian fluid

This paper studies the pullback asymptotic behavior of solutions for a non-autonomous incompressible non-Newtonian fluid in two-dimensional (2D) bounded domains. We first prove the existence of pullback attractors AV in space V (has H²-regularity, see notation in Section 2) and AH in space H (has L²-regularity) for the cocycle corresponding to the solutions of the fluid. Then we verify the regularity of the pullback attractors by showing AV=AH, which implies the pullback asymptotic smoothing effect of the fluid in the sense that the solutions become eventually more regular than the initial data.     

On-set of EHD turbulence for cylinder in cross flow under corona discharges

Experimental and theoretical investigations have been conducted for the on-set of electrohydrodynamically (EHD) induced turbulence for cylinder in cross flow. The experiments were conducted for Reynolds numbers from 0.2 to 80 based on cylinder diameters, and Reynolds numbers from 10³ to 4×10³ based on the flow channel width. This flow conditions represent laminar to transitional-flow before the on-set of the EHD-turbulent flow. Theoretical analysis was based on the mass, momentum, and charged particle conservation equations coupled with the Poisson's equation for electric field evaluation. The results showed that: (1) on-set of EHD turbulence is initiated near the real-stagnation point; (2) EHD turbulence can be generated even for Reynolds numbers (Re) less than 0.2, if the EHD number (Ehd) is larger than the critical Reynolds number square (Ehd>Re²); and (3) the electrical origin of instability, which is leading into the on-set of turbulence can be estimated from Ehd/Db²>Re² relation, where Db is the Debye number.     

Derivation of macroscopic relations of the elasticity of complex crystal lattices taking into account the moment interactions at the microlevel

A discrete mechanical model of a complex crystal lattice is proposed which contains particles possessing both translational and rotational degrees of freedom and which interact with one another by means of forces and moments. The transition to a continuum model of a crystal lattice is performed using the long-wave approximation, and, at the same time, it is shown that the dynamics of the continual model are described by the equations of the macroscopic moment theory of elasticity. Expressions are obtained for the macroscopic stiffness tensors which depend on the stiffness tensors of the interatomic bonds and the vectors determining the lattice geometry. A transition to the moment less theory of elasticity is made and it is shown that the macroscopic moduli of elasticity of the moment less theory depend both on the forces and the torque characteristics of the interatomic interaction. The stiffnesses of the interatomic bonds in a layer of graphite are calculated and it is shown that the transverse stiffness of an interatomic bond is comparable with the longitudinal stiffness, that is, a covalent bond is substantially non- central, which is only possible when there are torque interactions at the microlevel.     

浙江发展会展旅游的战略构想

通过对浙江会展旅游现状的分析和研究,总结了浙江会展旅游业的现状与优势,指出了面临的问题,进而从政府与会展企业角度提出了发展浙江会展旅游业的对策.     

Spin-Dependent Transport and Densities of States in Non-collinear Magnetic Barriers

The spin-dependent transport properties in the non-collinear pattern of series of δ-magnetic barriers are studied by using scattering theory and Green‘s function methods. The Green‘s function is obtained by using distorted wave approach and the scattering matrix is related by Fisher-Lee relationship. In addition to reproducing the results of Papp‘s and Xu‘s in parallel and antiparallel configurations, we also obtain further results, where arbitrary orientations of the magnetic barriers and arbitrary number of barriers are included. The main finding of our results is that the signs of polarizations can be switched around some “geometric unpolarized windows“. The well-known antiparallel configuration has no such characteristics. Furthermore, we discuss spin-related partial densities of states in both polarized and unpolarized structures.     

Multifractal PDF analysis for intermittent systems

The formula for probability density functions (PDFs) has been extended to include PDF for energy dissipation rates in addition to other PDFs such as for velocity fluctuations, velocity derivatives, fluid particle accelerations, energy transfer rates, etc., and it is shown that the formula actually explains various PDFs extracted from direct numerical simulations and experiments performed in a wind tunnel. It is also shown that the formula with appropriate zooming increment corresponding to experimental situation gives a new route to obtain the scaling exponents of velocity structure function, including intermittency exponent, out of PDFs of velocity fluctuations.     

CRW型交换子在Triebel-Lizorkin空间的有界性

本文考虑交换子[b,T]在 Triebel-Lizorkin 空间上的有界性,其中 b∈BMO(R~n),T 是卷积型奇异积分算子,其核为Ω∈L log~ L(S~(n-1)),给出了该交换子在 F_p~(s,p)(R~n)(s＞0,1＜p,q＜∞) 上有界的一个等价条件．     

造纸污泥与废水污泥流化床焚烧时NO_x和SO_2的排放特性研究

1前言流化床焚烧污犯是近年来发达国家广泛采用的方法，它能很好地实现污泥的稳定化、无害化、减容化和资源化处理。燃煤流化床锅炉污染物排放方面已做了大量的研究工作，由于污泥与煤在结构和性质方面的差异较大，因此有必要对流化床焚烧污泥时污染物排放特性进行研究。本文详细研究了造纸、废水污泥在流化床中焚烧时污泥水份、运行床温及过量空气对NO。和SO。的排放特性及污泥N－＋NO。、S－SO。的转化率的影响，并对这两种性质差异较大的污泥焚烧时的NO。和502的生成特性进行了对比分析，取得了许多有价值的结果，为污泥流化床焚烧…     

Anisotropies in soft magnetic nanocrystalline alloys

The article reviews and updates the understanding of the soft magnetic properties of nanocrystalline Fe-based alloys. In optimized compositions the random magneto-crystalline anisotropy of the structural phases is largely averaged out. The soft magnetic properties are then controlled by magneto-elastic and induced anisotropies which are uniform on a scale much larger than the exchange length. But unlike to the case of soft magnetic amorphous alloys, there is still a competition between the random and the more uniform anisotropy contributions. The experimental findings are complemented by theoretical results.