On SSOR iteration method for a class of block two-by-two linear systems

In this paper, the optimal iteration parameters of the symmetric successive overrelaxation (SSOR) method for a class of block two-by-two linear systems are obtained, which result in optimal convergence factor. An accelerated variant of the SSOR (ASSOR) method is presented, which significantly improves the convergence rate of the SSOR method. Furthermore, a more practical way to choose iteration parameters for the ASSOR method has also been proposed. Numerical experiments demonstrate the efficiency of the SSOR and ASSOR methods for solving a class of block two-by-two linear systems with the optimal parameters.     

A finite element analysis of a free surface drainage problem of two immiscible fluids

A sharp interface problem arising in the flow of two immiscible fluids, slag and molten metal in a blast furnace, is formulated using a two-dimensional model and solved numerically. This problem is a transient two-phase free or moving boundary problem, the slag surface and the slag–metal interface being the free boundaries. At each time step the hydraulic potential of each fluid satisfies the Laplace equation which is solved by the finite element method. The ordinary differential equations determining the motion of the free boundaries are treated using an implicit time-stepping scheme. The systems of linear equations obtained by discretization of the Laplace equations and the equations of motion of the free boundaries are incorporated into a large system of linear equations. At each time step the hydraulic potential in the interior domain and its derivatives on the free boundaries are obtained simultaneously by solving this linear system of equations. In addition, this solution directly gives the shape of the free boundaries at the next time step. The implicit scheme mentioned above enables us to get the solution without handling normal derivatives, which results in a good numerical solution of the present problem. A numerical example that simulates the flow in a blast furnace is given.     

α-唑基-α-芳氧烷基频哪酮(芳乙酮)及其醇式衍生物的合成和生物活性研究

对α－唑基－α－芳氧烷基频哪酮（芳乙酮）及其醇式衍生物的合成和生物活性进行了研究，合成了３３个新型化合物，所有化合物的结构均经核磁共振和元素分析证实；初步的生物活性测试结果表明，该类化合物具有一定的杀菌活性和植物生长调节活性．     

Novel solvent-controlled chemoselective palladium/copper(II) halide catalyzed oligomerization of <Emphasis Type="Italic">tert</Emphasis>-butyl acetylene

Solvent-controlled chemoselective palladium-catalyzed oligomerization of tert-butyl acetylene is reported in this paper. The reaction was carried out smoothly in benzene/n-BuOH binary solvent system. When unpolar aprotic benzene was the preponderating component in the binary system, a cyclotrimerization process occurred to produce 1,3,5-tri-tert-butylbenzene via a mechanism of three acetylene molecules, inserted step by step, forming σ-butadienyl-Pd and σ-hexatrienyl-Pd intermediates. While when the polar, protic and strong coordinating component n-BuOH, which aids Cu(II) to cleave the C-Pd σ-bonds and solvate Pd(II), Cu(II) cations, halo anion, σ-butadienyl-Pd intermediate, etc., was increased to a certain extent in the binary solvent system, the reaction proceeded readily via a n-BuOH-promoted mechanism to give (3Z,5Z)-2,2,7,7-tetramethyl-3,6-dichloro-3,5-octadiene or (3Z,5Z)-2,2,7,7-tetramethyl-3,6-dibromo-3,5-octadiene, respectively. Possible weak hydrogen bonds and n-π weak force between n-BuOH (electron pair donor (EPD)) and tert-butyl acetylene (and σ-butadienyl-Pd intermediate, electron pair acceptor (EPA)) in the latter process were also in favor of the n-BuOH promoted pathway. Meanwhile, the coupling product 2,2,7,7-tetramethyl-3,5-octadiyne was exclusively obtained when the reaction was conducted in singular polar H₂O. Influences of the solvent, catalysts, as well as possible mechanism were discussed in this paper.     

Reduction of NO x /SO2 by Wire-plate Type Pulsed Discharge Reactor with Pulsed Corona Radical Shower

Pulsed discharge deNO _x /deSO₂ process has been studied for over 20 years, but how to achieve higher removal rate at lower cost remains one of the crucial issues for realization of its industrial application. This paper presents a novel deNO _x /deSO₂ process that combines a wire-plate type pulsed discharge reactor and a corona radical shower. Our aim is to increase the deNO _x /deSO₂ rate of wire-plate type reactor by enhancing the generation of radicals with pulsed corona radical shower. Effect of a nozzle electrode on the production of OH radical was studied by emissive spectrum, and deNO _x /deSO₂ experiments using a wire-plate reactor with pulsed corona radical shower were conducted. The experimental results demonstrated that corona radical shower could enhance the production of radicals and the deNO _x /SO₂ performance of a wire-plate reactor. This study will play a positive role in the industrial application of wire-plate pulsed discharge deNO _x /deSO₂ reactor.     

Synthesis and Crystal Structure of the Complex [Zn（DBSHSH）（py）2]

1 INTRODUCTION Salicylaldehyde salicyloylhydrazone (SHSH) and their deviatives show moderate fungicidal and anti- bacterial activities[1]. Rao has reported some novel lanthanoid complexes of salicylaldehydrazone. Va- rious polyhedral geometries such as distorted octa- hedron, pentagonal bipyramid and distorted square antiprism were tentatively proposed for the com- plexes used as excellent semi-conducting materials[2]. Tang has studied spectrofluorimetric determination of hydrogen perox…     

Low temperature synthesis of Mn3O4 polyhedral nanocrystals and magnetic study

Manganese oxide (hausmannite) polyhedral nanocrystals were prepared by a microwave-assisted solution-based method using Mn(CH₃COO)₂ and (CH₂)₆N₄ at 80 °C. The as-prepared Mn₃O₄ nanocrystals were characterized by means of X-ray diffraction, field-emission transmission electron microscopy, field-emission scanning electron microscopy and Raman spectrum. Mn₃O₄ polyhedral nanocrystals prepared by microwave heating at 80 °C for 60 min were of cubic and rhombohedral shapes with the edge lengths in the range of 15-40 nm. Mn₃O₄ nanocrystals grew following the Ostwald ripening mechanism with increasing reaction time. High-resolution transmission electron microscopy and selected area electron diffraction confirm that the as-obtained polyhedral nanocrystals were single-crystalline. The magnetic behavior of Mn₃O₄ nanocrystals was studied. Mn₃O₄ nanocrystals show an obvious ferromagnetic behavior at low temperatures. The magnetic behavior of Mn₃O₄ nanocrystals was sensitive to crystal size. Ferromagnetic onset temperatures (T_c) of samples 1 and 3 are 40.6 and 41.1 K, respectively, lower than that observed for bulk Mn₃O₄ (42 K).     

离子液体在有机合成中的应用研究进展

离子液体由于具有特殊的性质, 包括低挥发性、大极性、良好的热稳定性、通过调整阴阳离子选择不同的溶解性等特点, 已经作为反应介质或催化剂广泛应用于有机合成领域, 引起了人们足够的兴趣. 与传统有机溶剂反应相比, 离子液体相反应得到的产物收率高, 选择性好, 加快部分类型反应的速率, 后处理简单以及离子液体催化剂体系简单, 回收后, 可多次重复使用. 综述了离子液体作为反应介质或催化剂在有机合成传统反应类型中的最新研究成果, 主要包括: 偶联反应、Michael加成、Baylis-Hillman反应、Diels-Alder反应、Aldol缩合、Knoevenagel缩合、环化反应、烷基化及酰基化反应和氧化还原反应.     

Calculation of the heat deposition and temperature distribution of the target bombarded by high-energy protons using Monte Carlo simulation and finite element method

The Monte Carlo simulation and the finite element methods have been used to calculate the heat deposition and temperature distribution in tungsten plate target when the target is bombarded by high-energy protons from the accelerator with nuclear power of 100 kW. The results show that the heat deposition in the target, reflector and shield will be 48 kW, 15 kW and 11 kW, respectively, and the highest temperature in the target plates will be lower than 100℃ when the surfaces of plates are cooled by water.     

Generation of Bell states in two-component Bose－Einstein condensates

We examine analytically the generation of Bell state in Bose condensates of two interacting species trapped in a double well configuration. The density of probability for finding the entangled Bell state is given. The effect of the tunnelling rate and the interspecies interaction strength on the generation of Bell state is discussed. We find that the oscillation amplitude of the density of probability for finding the entangled Bell state becomes greater as the tunnelling rate Ω increases, and the self-interaction strength of the component A(B) has no effect on it.