Large time behavior of solutions for critical and subcritical complex Ginzburg-Landau equations in H<Superscript>1</Superscript>

Considering the Cauchy problem for the critical complex Ginzburg-Landau equation in H¹(Rⁿ), we shall show the asymptotic behavior for its solutions in C(0, ∖;H¹(Rⁿ)) ∩ L²(0, ∖;H^1,2n/(n-2)(R²)), n≥3. Analogous results also hold in the case that the nonlinearity has the subcritical power in H¹(Rⁿ), n≥1. Dedicated to Professor Zhou Yulin for his 80th birthday.     

Synchronization of underdamped Josephson-junction arrays

Our recent experiments show that arrays of underdamped Josephson junctions radiate coherently only above a threshold number of junctions switched onto the radiating state. For each junction, the radiating state is a resonant step in the current-voltage characteristics due to the interaction between the junctions in the array and an electromagnetic cavity. Here we show that a model of a one-dimensional array of Josephson junctions coupled to a resonator can produce many features of the coherent be havior above threshold, including coherent radiation of power and the shape of the array current-voltage characteristic. The model also makes quantitative predictions about the degree of coherence of the junctions in the array. However, in this model there is no threshold; the experimental below-threshold region behavior could not be reproduced.Received: 11 April 2003, Published online: 23 July 2003PACS: 74.50.+r Tunneling phenomena; point contacts, weak links, Josephson effects - 85.25.-j Superconducting devices     

Unique Continuation at the Boundary for Elliptic Operators in Dini Domains

Let u be the solutions to some elliptic equations of the form

Magnetic characterization of ZnO doped with vanadium

The magnetic properties of vanadium doped ZnO nanorods formed by different growth methods were examined. The samples under investigation were either grown by metallorganic vapour-phase epitaxy (MOVPE) with in situ incorporation of the V atoms or by aqueous chemical growth (ACG) in combination with an ion-implantation process. The V concentration for all samples was less than 2 at.%.Field-cooled SQUID measurements only reveal a weak ferromagnetic signal still in a very sensitive measuring range. However, the MFM micrographs obtained at room temperature show a clear magnetic contrast and complex structures, the images are in good agreement with the phase images expected for vertically aligned magnetic dipoles. This is a strong indication for a ferromagnetic behaviour at room temperature.     

用双粒子模型研究微量元素与Ni在Ni3Al晶界共富集现象

双粒子模型的基础是描述原子之间相互作用势为EAM(embedded atom method)势的Monte Carlo模拟. 模型建议：在Ni₃Al晶界弛豫时，微量元素原子既被看作为偏析子又被看作为诱发子. 作为偏析子它在晶界偏析(或富集)，作为诱发子它诱发Ni原子在晶界偏析(或富集). 可见本模型能解析共偏析(或共富集)现象. 根据正(或诱发子)效应与负(或偏析子)效应的联合影响，模型解释了Ni在Ni₃Al晶界最明显富集现象. 关键词： 偏析子与诱发子 基体效应 在晶界共富集 晶界内聚性     

Polyhedral cones and positive operators

Some results are obtained relating topological properties of polyhedral cones to algebraic properties of matrices whose columns are the extremal vectors of the cone. In addition, several characterizations of positive operators on polyhedral cones are given.     

A microcomputer-controlled vacuum adiabatic calorimeter for the temperature range 4.2–300 K

In this paper, we describe the operation of a vacuum adiabatic calorimeter controlled by a Rockwell AIM 65 microcomputer, which is suitable for specific heat measurements in the temperature interval 4.2–300 K. The system measures and calculates the specific heat and the results are printed out on a thermal tape. The cryostat, the electronic circuitry and the software are described. Results obtained using a pulsed heat technique on a specimen of high purity copper are given and compared with values reported in the literature.     

Dilatometric study of β-alumina single crystals

Single crystals of β-alumina exhibit an important dilatometric anisotropy. The anisotropic factor is about three for βNa-alumina. Variations of this factor are followed according to the nature of the conducting ion and the stoichiometry. The dilatometric behaviour of these compounds is explained (up to 800°C) from previous structural results.     

A synthesis of (±)-cryptojaponol and (±)-taxodione

A new method for the synthesis of highly substituted catechols involving the decarboxylation of an α,β-epoxyenone was developed and employed in a synthesis of two diterpenes, cryptojaponol and taxodione.