无线分布式系统中基于移动Agent的日志分析

在分布式系统中,利用移动Agent主动读取和分析各结点的数据库事务日志,并与其他结点的移动Agent相互协作,共同完成数据的校验和检测,从而实现整个系统数据的一致性、完整性,利用该方法实现了多结点无线分布式系统中SQL Server2000数据库数据的一致性存储,并在工程实践中取得了满意的效果。     

特种设备信息加密系统设计

对特种设备信息的加密系统进行设计,目前存在信息加密不彻底和采集的可靠性较低等问题。为此,提出特种设备加密系统设计方法,通过信息接口模块完成特种设备中信息的输入和输出,信息流程编辑模块负责开发设备中信息加密流程的组件,完成对特种设备中任务流程的检验,信息流程调度模块对信息流程任务进行调度管理。系统软件设计部分采用数据加密改进方法使信息源节点将要传输的多份信息数据分解成互不相关的信息数据,完成特种设备信息加密系统的设计。实验结果表明,所设计系统信息加密效果好、信息的完备性较高。     

Study of the closing mechanism of natural heart valves

At present, there are still some controversial considerations on the closing mechanismof natural heart valves. In this area. a lot of phenomena still remain mysterious.particularlyfor the mechanism of earlier partial closure of the valve white the blood ejection is still in itsacceleration phase. It is the purpose of this study to focus on the problem of earlier closuremechanism of heart valves by using both theoretical analysis and experimentalverifications. A certain two-dimensional mathematical model of closure with allcontributing factors and the whole operating process being considered is investigated with anew analytical method Several new conclusions were found. The main points are asfollows:I. During the opening phase, the main factor of motion of the valve is the acceleratingflow, and the decelerating flow plays a main role during most the of time of the decelerationphase. But during the quasi-steady phase of blood ejection. it is the vortex in the sinus thatcontrols the valve closure.2. For Ih     

Simulation of the Quasi-Monoenergetic Protons Generation by Parallel Laser Pulses Interaction with Foils

A new scheme of radiation pressure acceleration for generating high-quality protons by using two overlappingparallel laser pulses is proposed. Particle-in-cell simulation shows that the overlapping of two pulses with identical Caussian profiles in space and trapezoidal profiles in the time domain can result in a composite light pulse with a spatial profile suitable for stable acceleration of protons to high energies. At～2.46 × 10^21 W/cm^2 intensity of the combination light pulse, a quasi-monoenergetic proton beam with peak energy ,～200 MeV/nucleon, energy spread 〈15%, and divergency angle 〈4° is obtained, which is appropriate for tumor therapy. The proton beam quality can be controlled by adjusting the incidence points of two laser pulses.     

黏弹性流体基铜纳米流体流动与传热实验研究

成功建立了流体流动阻力和换热性能测试实验台,在45℃的流体温度下,对不同铜粒子体积分数和基液浓度的纳米流体在湍流状态下的对流换热特性和流动阻力进行了实验测量。实验结果表明:黏弹性流体基液中添加纳米粒子后,在降低对应基液减阻率的同时能明显增强传热性能.例如,将1.0%体积分数的铜纳米粒子添加到质量分数为6×10~(-4)的基液中所形成的黏弹性流体基纳米流体其综合性能指数K=0.47,表现了很好的传热强化和减阻性能.     

Structural transition, dielectric and bonding properties of BeCN2

By means of first principle total energy calculations, this paper studies the structural transition, elastic, mechanical, dielectric and electronic properties of BeCN₂. The calculations in total energy indicate that under ambient condition, the orthorhombic BeSiN₂-type BeCN₂ (space group Pna2₁) is a more favoured structure than the tetragonal chalcopyrite-type one (space group I-42d). The results of elastic properties reveal that BeCN₂ in both orthorhombic and tetragonal structure has higher bulk and shear moduli and smaller Poisson's ratio. The calculated Vicker hardness of tetragonal phase is 36.8 GPa, indicating a hard material. The analyses of electronic structure and electron density difference demonstrate that these excellent mechanical properties are attributed to the stronger covalent-bonding of CN₄ and BeN₄ subunits in BeCN₂ crystal. Also, the orthorhombic BeCN₂ phase is found to be a transparent semiconductor material with the calculated direct band gap of about 5.56 eV, superior to the indirect band gap of diamond and c-BN. Moreover, it also calculates Born effective charges and dielectric constants of BeCN₂. These results suggest that BeCN₂ may have some useful applications as optoelectronic, optical window and wear resistant materials.     

解析197号令

2010年11月15日,海关总署发布第197号令,颁布修订后的《中华人民共和国海关企业分类管理办法》（以下简称“新《办法》”或“《办法》”）。《办法》自2011年1月1日起施行,之前实施的《中华人民共和国海关企业分类管理办法》（海关总署于2008年以海关总署令第170号发布,以下简称“原《办法》”）将同时废止。     

532 nm纳秒激光辐照下的单晶硅表面微结构及荧光特性

采用Nd:YAG纳秒脉冲激光对单晶硅在空气中进行辐照,研究了表面微结构在不同能量密度和扫描速度下的演化情况。扫描电子显微镜测量表明,激光在相对较低能量密度下辐照硅表面诱导出鱼鳞状波纹结构,激光能量密度相对较大时,诱导出絮状多孔的不规则微结构。光致荧光谱（PL）表明,激光扫描区域在710 nm附近有荧光发射。用氢氟酸腐蚀掉样品表面的SiOx后,荧光峰的强度显著降低,说明SiOx在光致发光增强上起重要作用。能量色散X射线谱（EDS）表明氧元素的含量随激光能量密度的增大而增加。研究表明：纳秒激光的能量密度和扫描速度对微结构形成起着决定性作用,改变了硅材料表面微结构尺寸,增大了光吸收面积; 氧元素在光致发光增强上起重要作用,微构造硅和SiOx对光致荧光的发射都有贡献。