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161.
A simple algorithm to calculate the maximum torsional load for a cylindrical shaft is presented. The algorithm is based on
the notion of viscosity solutions to the eikonal equation, and is not restricted to simply-connected cross-sections. Applications
to other, related problems, such as ferromagnetic thin films, and elastic buckling of thin film blisters are also discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
162.
This paper presents new criteria for stability properties of discrete-time non-stationary systems. The criteria are based on the concept of asymptotically contractive sets. As a result, general necessary conditions are established for asymptotic stability of the zero equilibrium state, the instantaneous asymptotic stability domain of which can be either time-invariant or time-varying and then possibly asymptotically contractive. It is shown that the classical Lyapunov stability conditions including the invariance principle by LaSalle cannot be applied to the stability test as soon as the system instantaneous domain of asymptotic stability is asymptotically contractive. In order to investigate asymptotic stability of the zero state in such a case novel criteria are established. Under the criteria the total first time difference of a system Lyapunov function may be non-positive only and still can guarantee asymptotic stability of the zero state. The results are illustrated by examples. 相似文献
163.
王梦 《浙江大学学报(理学版)》1999,26(4):1-7
本文讨论了乘积域Rn×Rm上一类带粗糙核的奇异积分算子的Lp(Rn×Rm)有界性。这里,Ω为原子Hardy空间H1a(Sn-1×Sm-1)中的函数,h为L∞(Lq)(R+×R+)中的径向函数,Φ(t)满足一定的增长条件。 相似文献
164.
贾厚玉 《浙江大学学报(理学版)》1999,26(2):1-7
本文主要讨论在有界凸区域上具Lipschitz连续系数的散度型椭圆算子的解的二阶导数的可积性问题.并且得到了相应的结论. 相似文献
165.
Stephen R. Wassall Saame Raza Shaikh Michael R. Brzustowicz Vadim Cherezov Rafat A. Siddiqui Martin Caffrey William Stillwell 《Macromolecular Symposia》2005,219(1):73-84
Unequal affinity between lipids has been hypothesized to be a mechanism for the formation of microdomains/rafts in membranes. Our studies focus upon the interaction of cholesterol with polyunsaturated fatty acid (PUFA)-containing phospholipids. They support the proposal that steric incompatibility of the rigid steroid moiety for highly disordered PUFA chains, in particular docosahexaenoic acid (DHA), provides a sensitive trigger for lateral segregation of lipids into PUFA-rich/sterol-poor and PUFA-poor/sterol-rich regions. Solid state 2H NMR and x-ray diffraction (XRD) demonstrate that the solubility of cholesterol is reduced in 1-palmitoyl-2-docosahexaenoyl-phosphatidylethanolamine (16-0:22:6PE) bilayers. In mixed membranes of phosphatidylethanolamine (PE) with the lipid raft forming molecules egg sphingomyelin (SM) and cholesterol, diminished affinity of the sterol for 16:0-22:6PE relative to 1-palmitoyl-2-oleoylphosphatidylethanolamine (16:0-18:1PE) is identified by 2H NMR order parameters and detergent extraction. Phase separation of the PUFA-containing phospholipid from SM/cholesterol rafts is the implication, which may be associated with the myriad of health benefits of dietary DHA. 相似文献
166.
We study Tsirelson type spaces of the form T[(ℳ︁k, θk)lk=1] defined by a finite sequence (ℳ︁k)lk=1 of compact families of finite subsets of ℕ. Using an appropriate index, denoted by i(ℳ︁), to measure the complexity of a family ℳ︁, we prove the following: If i(ℳ︁k) < ω for all k = 1, …, l, then the space T[(ℳ︁k, θk)lk=1] contains isomorphically some lp, 1 < p < ∞, or c0. If i(ℳ︁) = ω, then the space T[ℳ︁, θ] contains a subspace isomorphic to a subspace of the original Tsirelson's space. 相似文献
167.
168.
We study the embeddings E : W(X(Ω), Y(Ω)) ↪ Z(Ω), where X(Ω), Y(Ω) and Z(Ω) are rearrangement–invariant Banach function spaces (BFS) defined on a generalized ridged domain Ω, and W denotes a first–order Sobolev–type space. We obtain two–sided estimates for the measure of non–compactness of E when Z(Ω) = X(Ω) and, in turn, necessary and sufficient conditions for a Poincaré–type inequality to be valid and also for E to be compact. The results are used to analyse the example of a trumpet–shaped domain Ω in Lorentz spaces. We consider the problem of determining the range of possible target spaces Z(Ω), in which case we prove that the problem is equivalent to an analogue on the generalized ridge Γ of Ω. The range of target spaces Z(Ω) is determined amongst a scale of (weighted) Lebesgue spaces for “rooms and passages” and trumpet–shaped domains. 相似文献
169.
Let Lqr(Ω) be the usual scale of Sobolev spaces and let ΔN be the Neumann Laplacian in an arbitrary Lipschitz domain Ω. We present an interpolation based approach to the following question: for what range of indices does map isomorphically onto Lqr(Ω)/ℝ? 相似文献
170.
F. Assous P. Ciarlet P.‐A. Raviart E. Sonnendrücker 《Mathematical Methods in the Applied Sciences》1999,22(6):485-499
The solution of Maxwell's equations in a non‐convex polyhedral domain is less regular than in a smooth or convex polyhedral domain. In this paper we show that this solution can be decomposed into the orthogonal sum of a singular part and a regular part, and we give a characterization of the singular part. We also prove that the decomposition is linked to the one associated to the scalar Laplacian. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献