Numerical analysis of the rotating viscous flow approaching a solid sphere

A numerical simulation is performed to investigate the flow induced by a sphere moving along the axis of a rotating cylindrical container filled with the viscous fluid. Three‐dimensional incompressible Navier–Stokes equations are solved using a finite element method. The objective of this study is to examine the feature of waves generated by the Coriolis force at moderate Rossby numbers and that to what extent the Taylor–Proudman theorem is valid for the viscous rotating flow at small Rossby number and large Reynolds number. Calculations have been undertaken at the Rossby numbers (R_o) of 1 and 0.02 and the Reynolds numbers (R_e) of 200 and 500. When R_o=O(1), inertia waves are exhibited in the rotating flow past a sphere. The effects of the Reynolds number and the ratio of the radius of the sphere and that of the rotating cylinder on the flow structure are examined. When R_o ? 1, as predicted by the Taylor–Proudman theorem for inviscid flow, the so‐called ‘Taylor column’ is also generated in the viscous fluid flow after an evolutionary course of vortical flow structures. The initial evolution and final formation of the ‘Taylor column’ are exhibited. According to the present calculation, it has been verified that major theoretical statement about the rotating flow of the inviscid fluid may still approximately predict the rotating flow structure of the viscous fluid in a certain regime of the Reynolds number. Copyright © 2004 John Wiley & Sons, Ltd.     

一种高温超导磁悬浮装置

本文介绍一个基于倒挂吸引式(EMS)原理的高温超导磁悬浮试验装置．这个装置由高温超导磁体、单臂梁金属导轨、位置传感器、控制电路等组成．绕制超导磁体线圈所用的是Bi-2223／Ag高温超导线材．超导磁体工作在激磁电流为3．2A时，在5mm的空气间隙中产生0．21T的磁通密度，与单臂梁金属导轨可产生72N的垂直悬浮力．通过引入压控电流源，利用常规的超前一滞后校正实现了该磁悬浮装置的稳定悬浮和鲁棒控制，在负载变化87．5%的情况下仍能实现超导磁悬浮装置的稳定悬浮．该试验装置首次验证了高温超导线圈的可控性问题，为进一步探索高温超导线圈用于磁悬浮轨道交通系统的可行性打下了基础．     

Crystallographic report: Crystal structure of tetra(4‐methyl‐5‐imidazole‐carboxyaldehyde)zinc(II) diperchlorate

The central zinc(II) atom in the title complex is tetrahedrally coordinated by four nitrogen atoms derived from 4‐methyl‐5‐imidazolecarboxyaldehyde ligands with Zn? N in the range 2.007(3) to 2.026(4) Å. Copyright © 2003 John Wiley & Sons, Ltd.     

ICF研究中的Rayleigh-Taylor不稳定性实验用靶

 概述了当前研究Rayleigh-Taylor不稳定性增长实验所用的靶型情况。从实验用靶来看，调制靶的设计正从平面向立体发展，出现了球形和柱形等新靶形，制备手段包括精密机械微加工、激光束、电子束和离子束加工、半导体工艺和微米纳米技术加工等。根据对国外新靶型的研究，结合国内工艺条件和实验需求，对国内可能采用的靶型进行了研究探索。     

Synthesis of 4,6-disubstituted pyrimidines via Suzuki and Kumada coupling reaction of 4,6-dichloropyrimidine

A series of 4,6-disubstituted pyrimidines were synthesized via Suzuki and Kumada coupling reaction of 4,6-dichloropyrimidine.     

CT实验仪的研制及其在物理教学中的应用

介绍了我们研制的CT实验仪的原理及开发，使用情况，包括CT的物理，数学原理，CT装置的结构，性能、工作原理等，文末给出实验结果，并对装置在物理实验教学中的意义作了讨论。     

SURFACE METALLIZATION OF CENOSPHERES AND PRECIPITATORS BY ELECTROLESS PLATING

This paper reports the use of a colloidal Pd^0 catalysis system to metallize the surface of precipitators separated from coal fly-ash, and metals such as Cu, Ni etc. are deposited on the precipitators surface. Alternatively, according to the characteristic surface of cenospheres, an Ag coating catalysis system is adopted to first deposit Ag on the cenospheres surface, followed, if necessary, by the deposition of other metals such as Cu, Ni, etc. on the Ag coating to produce monolayer and multilayer metal-coated cenospheres. The surface characteristics and the morphologies of the metal coatings are examined in detail with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) techniques. It can be shown that the quality of metal coatings derived from the Aa coatina catalysis system, is better than that of the colloidal Pd^0 catalysis system.     

ON THE COHOMOLOGY OF GENERALIZED RESTRICTED LIE ALGEBRAS

0.IntroductionThispaperisaimedatdevelopingthecohomologytheoryofmodularLiealgebrasandthendeterminingthefirstcohomologygroupsofCartantypeLiealgebras.AsgeneralizationoftheconceptofrestrictedLiealgebras,ageneralizedrestrictedLiealgebra(GRLiealgebra)wasintroducedin[21],whichisassociatedwithabasisandamappingofthebasisintotheLiealgebrasatisfyingthegeneralized-restrictednessconditions.Generalizedrestrictedrepresentations(GRrepresentations)werethenintroduced,whichcanbereducedtotherepresentationsofa…     

Experimental Studies on Thermal and Electrical Properties of Platinum Nanofilms

We experimentally studied the in-plane thermal and electrical properties of a suspended platinum nanofilm in thickness of 15 nm. The measured results show that the in-plane thermal conductivity, the electrical conductivity and the resistance-temperature coefficient of the studied nanofilm are much less than those of the bulk material, while the Lorenz number is greater than the bulk value. Comparing with the results reported previously for the platinum nanofilm in thickness of 28 nm, we further find that the in-plane thermal conductivity, the electrical conductivity and the resistance-temperature coefficient decrease with the decreasing thickness of the nanotilm, while the Lorenz number increases with the decreasing thickness of the nanofilm. These results indicate that strong size effects exist on the in-plane thermal and electrical properties of platinum nanofilms.