流动

According to the understanding of the flow characteristics, a mechanism of formation of vortex streets has been proposed to be the absolute instability of the wake, and several methods of flow control have been developed and shown successful.

根据表面流动及尾流特性的研究结果，从流动稳定性的角度提出了尾流中涡街产生的机理，在于尾流中存在着绝对不稳定的区域。基于对流动特性的理解，从改变流动稳定性的角度，寻求各种流动控制方法。试验结果表明这些方法是成功的。

Correctional checking formula of melt flow ratio in injection molding was obtained by introducing a correction coefficient β which reflected the complexity degree of mold cavity. The results show that, the maximum flow ratio of 486 can be obtained when injection pressure ranges from 150 MPa to 160 MPa in Archimedes spiral mold for PP, while maximum flow ratio of 419 can be obtained when injection pressure ranges from 160 MPa to 170 MPa for PE. There is a local fluctuation phenomenon for flow ratio and corresponding injection rate in square spiral mold when injection pressure of 100, 120 and 150 MPa for PP and 130, 140 MPa for PE are reached respectively,and this phenomenon is more serious for good fluidity of melt. The average flow ratio in Archimedes spiral mold is 6% larger than that in square spiral mold for PP, and 4% for PE, the average flow ratio of PP is 19% bigger than PE in Archimedes spiral mold, and 15% in square spiral mold. The influence of the cavity profiles on the melt flow ratio is more significant for good fluidity of melt.

研究结果表明：在阿基米德螺旋线模具中，PP在注射压力为150~160 MPa时取得最大流动比485，PE在注射压力为160~170 MPa时取得最大流动比419；在方形螺旋线模具中，PP在注射压力为100，120和150 MPa，PE在注射压力为130和140 MPa时流动比及所对应的注射速率出现波动，且流动性好的熔体波动更为严重；PP在阿基米德螺旋线模具中的流动比均值较其在方形螺旋线模具中大6%，而PE大4%；在阿基米德螺旋线模具中流动比均值PP比PE的流动比均值大19%，而在方形螺旋线模具中PP的流动比均值比PE的大15%；流动性好的熔体受模具型腔轮廓特征影响大。

The most common ratio using current asset and current -liability data is the current ratio, which is

利用流动资产和流动负债数据计算的最常见的比率是流动比率，即流动资产除以流动负债。

The characteristic and difference of flow in porous media between the pseudo-plastic fluids and the expansile fluids was described in detail. The experimental pressure drop measurements were made in a packed bed under a variety of conditions, and the variation of the friction factor with the Reynolds number was obtained. Corresponding to the flow resistance in a nonporous channel, the flow resistance in porous media can be divided into Darcy resistance and Forchheimer resistance as well. The experiment data was divided into Darcy regime, transitional regime and Forchheimer regime in accordance with the Reynolds number.

实验测定了不同浓度聚丙烯酰胺溶液在五组填充多孔介质中流动的压降-流量关系，绘出了阻力因子随Reynolds数变化的关系曲线；按照将流动阻力分为层流粘性阻力和惯性阻力的观点，将多孔介质流动阻力分为Darcy阻力和Forchheimer流动阻力；参考有关文献，将实验区域按Reynolds数范围分为Darcy流动、过渡流动和Forchheimer流动。

The main work and innovation of this dissertation are: 1. The network management domain-specific mobile agent system architecture and mobile agent model are proposed and described in details. The lifecycle of mobile agent is described by using state diagram. The layered security model is introduced. The mobility model is distinguished by the complete and partial one as well as the explicite mobility and implicite one. 2. Aimming at the complexity and heterogeneity of the network, the abstract network entity is presented and defined in details. The mobile agent is also classified and studied from the point of the mobile mechinisim along with the resposibility view. The NMBMA, which the main component is ANE, is put forward and described by using organizational, informationl, computational and implementary model. 3. The two architectures, NMBMA and Client/Server-based one, are compared and analyzed quantitatively and qualitatively. 4. The prototype based on the above NMBMA is designed and some examples are described in the prototype.

主要工作与创新是：提出并详细描述了面向网络管理领域的MAS结构和流动软件代理模型及其内部结构，并采用状态图描述了流动代理的生命周期；提出了层次的安全模型；从数据管理和实现方式两个方面，区分了流动模型即完全流动和部分流动以及显式流动和隐式流动；针对网络的异构性和复杂性，提出了抽象网络实体ANE的概念，并进行了定义；从流动机制和职能两个角度，对流动代理进行了分类研究；以ANE为主要部件，从组织模型、信息模型、通讯模型、实施模型四个侧面描述了NMBMA；定量和定性比较分析了NMBMA与传统的基于Client/Server模型网络管理体系结构；通过一个原型系统的设计和网络管理实例，验证了NMBMA是可行的。

In this paper the importation of translations that the value orientation of personnel, organization and personnel employment orientation towards the mobile space changes focusing on concepts, organizations, systems, cultural, and social aspects of China's human impact on the flow of major issues, from the political, economic, cultural, market, environment etc., the promotion and protection of the rational flow of talents to deal with comments and suggestions, as follows: In politics, setting up the political sense of talent with the progress of time spirit, implementing roundly the strategy to strengthen nation by relying on talent, establishing quickly the system to manage talent and reforming the system of personnel; In economy,talent flow corresponding with economic construction, assorting talent's structure with economic structure, paying attention to the economic benefit from talent flow, quickening to construct the social welfare system of talent, founding the flexible system of employment and reducing the cost of talent flow; In culture, stressing on the functions of culture for talent flow, cultural model corresponding with the model of talent flow, sparking plug the excellent culture to facilitate talent flow and erecting the cultural system to motivate talent flow; In marketing, unifying the thinking to developing talent market, enhancing the construction of talent market and fastening the growth of service agency for talent; In surroundings, grasping the elements of talent surroundings, optimizing the circumstance of talent flow and building the condition to look after the security of talents.

本文指出了人才价值取向、组织用人取向和人才流动空间走向的变化，着重从观念、组织、制度、文化、社会等方面具体分析了影响我国人才流动的主要问题，从政治、经济、文化、市场、环境等方面研究，提出了促进和保障人才合理流动的意见和建议，包括：树立与时俱进的人才政治理念，全面实施人才强国战略，加快构建人才领导体制，改革创新人事制度等政治对策；人才流动与经济建设对应，人才结构与经济结构协调，讲求人才流动的经济效益，加快人才社会保障体系建设，建立灵活的就业体制，降低人才流动的经济成本等经济对策；注重文化功能对人才流动的作用，倡导促进人才流动的优秀文化，构建激励人才流动的文化机制等文化对策；统一人才市场发展思路，突出人才市场建设重点，加快人才服务业的成长等市场对策；优化人才流动环境，构建人才安全环境等环境对策。

The results show that the flow length of microfluid in micro channels that have different section shapes but the same length(50 mm) is in inverse proportion to sections RPA (RPA means the ratio of the section s perimeter to its area),and the smaller the RPA , the longer the flow length.

研究结果表明：微流体在截面形态不同，长度均为50 mm微流道中的流动长度与流道截面的比表面积(截面周长与截面面积的比值)呈反比关系，比表面积越小，流动长度越大；当微流道的比表面积较小时，熔体温度与注射压力对流动长度的影响较大；当比表面积较大时，熔体温度与注射压力对流动长度的影响较小，且不论比表面积如何变化，注射压力对流动长度的影响比熔体温度对流动长度的影响显著。

Any high Re number flow over bodies consists of three basic flows: the flow with convection-dominant in all spatial directions, the flow with convection-diffusion competition in all directions and the flow with convection-dominant in part directions and convection-diffusion competition in part directions, which is called the interacting shear flow; the features of the three basic flows are different; their simplest conservation equations, i.e. the Euler equations, Navier-Stokes equations and diffusion parabolized NS equations, have different mathematical characteristics; there is a great disparity in domains of the three basic flows and the domains of NS equations are very small. Therefore, adopting Euler-DPNS-NS equation system to analyze and compute high Re number flows over bodies is a logical approach. There exists a mutual examined-complemented relationship of this approach with the usual one of adopting only NS equations.

主要内容如下：（1）高Re数绕流包含3种基本流动：所有方向对流占优流动、所有方向对流扩散竞争流动和部分方向对流占优部分方向对流扩散竞争流动，3个基本流动的特征彼此不同且在流场中所占领域大小彼此相差悬殊，NS方程区域很小，它们的最简单控制方程组Euler、Navier-Stokes和扩散抛物化NS方程组的数学性质彼此不同，因此利用Euler-DPNS-NS方程组体系分析计算高Re数绕流流动就是一个合乎逻辑的选择，该法与利用单一NS方程组的常用方法可以彼此检验和补充。

The simulation results of the cylinder-block model were given in the article, consistent with that of Middlemen"s. It was shown that the block part could improve the uniformity of the flow distribution. The analysis of the flow field of some materials with different power-law factor in the die designed by Mckelvey was close to that of Mckelvey"s. It was shown that the flow distribution was uniform in the die that can producesheets with 1200mm in width. During the analysis the flow channel was divided into several parts to get the details about the fluid flow in each area. A conclusion was drawn after analyzing the influence of the die pressure on the flow distribution, that the higher pressure is good for the output and bad for the uniformity of the distribution. Simulation of the die applying the cylindrical main runner showed the fact that when the cylinder replaced the cone the change of uniformity was trivial. The uniformity of the non-block flow channel was so poor that the block in the proper position of the die channel was necessary. The project of the die for the wider sheet was put forth, and the analysis of the fluid flow in the die was shown.

本文模拟了圆柱管缝隙流模型的三维流动场，得到了与Middlemen结论一致的流动均匀性，并通过模拟直观地展示了采用阻尼块可以改善挤出均匀性的现象；分析了多种幂率指数的流体在Mckelvey等人设计的流道模型中的流动分布，得到了与Mckelvey的分析结果接近的压力降和流量偏差；本文建立了1200mm幅宽机头流道的三维有限元模型，并逐个分析各个区域和多个截面的流动分布状况，由此揭示了1200mm幅宽L-型机头流道内的流北京化工大学硕士学位论文动分布基本均匀，并在分析了机头压力对于挤出流动分布的影响后得出结论：较高的机头压力可以获得较大的产量，但是不利于物料均匀分布；模拟了采用圆柱管主流道时机头流道内的流动分布，得出结论：主流道由圆锥管改为圆柱管时对流动均匀性影响不大，通过设置适当的阻尼仍然可以达到挤出平衡；模拟了两端进料式圆柱管无阻尼流道的流动均匀性后得到结论：两端进料式无阻尼结构的流动均匀性较差，宽机头中仍然有必要设置阻尼块；确定宽幅机头流道的基本方案，并设计了一种宽幅防水卷材挤出机头流道的结构，通过流动模拟表明该种结构的流动均匀性较好；考察了宽幅机头对于不同厚度片材的挤出适应性，得到结论：当生产不同厚度的片材时，阻尼块高度需要调整。

Models on three types of social mobility demonstrate the obvious differences of factors influencing residential mobility of persons with different types of social mobility. Persons of upward social mobility obtain more chances of residential mobility in any period of housing reform because of their higher social and economic status, no matter in planning system or market system. Persons of downward social mobility nearly do not enjoy any benefit in housing reform and housing market construction, and consequently have the lowest residential mobility rate. Persons of horizontal mobility only obtain more chances of residential mobility in the most radical period of housing reform.

分社会流动模型则显示出改革开放以来不同社会流动类型人群居住流动所受到的影响因素存在较大的差异，上升社会流动者因为其较高的社会经济地位，在改革的任何一个阶段，无论是计划体制中还是市场体制下都获得了最多的居住流动机会；而下降社会流动者基本未得到住房制度改革的利益，居住流动机率最低；水平社会流动者仅在住房改革最剧烈的阶段获得了较多的居住流动机会。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。