管

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。

In this paper, the residual contact pressure and static interface friction coefficient of tube - to - tube-sheet joints of heat exchangers is investigated.

本文采用换热器管板单管模型研究了换热管与其液压胀接后的残余接触压力和静摩擦系数。用弹性卸载法测量了换热管从单管胀接模型中拉出后，模型外表面的周向应变，并由此计算出接触面处的残余接触压力的实验值。

The main products have different specifications, different linear and different colors Mascara (gourd-shaped), cone tube, straight tube, fan-shaped tubes, flat tubes, flat tubes, such as the mouth tube.

主要产品有各种不同规格、不同线型和不同颜色的马斯卡拉、锥体管、直管、扇形管、扁管、扁嘴管等铝管。

Based on gun bore radial wear Δdmax as discrimination condition of barrel life the mathematical model for predicting melt-erosion of gun-barrel is established which is employed in analyzing factors affecting the life of gun such as material, gun powder,firing conditions and so on. It is pointed out that active cooling technology is an effective method for solving many problems concerned with heat transfer each time the gun is fired.

文中由身管寿命判别条件△d_建立了身管熔化烧蚀预测计算模型，从原理上对各种延缓烧蚀速度、提高身管寿命的措施，如采用内膛镀铬、使用冷火药和护膛剂等进行了阐述；同时基于该模型指出采用身管主动冷却技术是延长火炮身管寿命最有效的措施之一。

Company invincible in 1996, initially to produce electric coil, electric heating plate mainly; With the rapid development of industry and market demand, the company began producing a variety of multi-purpose electric components, such as stainless steel heating tube, far infrared heating tube, quartz glass electric heating tube, ceramic electric heating tubes, pipes of various liquid products such as electric heating, the product is widely used in plastics, electronics, electrical appliances, hardware, food, medical, chemical, farming and other industries.

公司立于1996年，起初以生产电热圈、电热板为主；随着工业的迅速发展及市场的需求，公司开始生产各种多用途电热元件，如不锈钢电热管、远红外电热管、石英玻璃电热管，陶瓷电热管、各种液体加热电热管等产品，产品广泛用于塑胶、电子、电器、五金、食品、医疗、化工、养殖等各行业。

C. Silicon carbide products: with excellent thermal conductivity, high temperature thermal stability, higher softening point load and high wear resistance, professional production of various shapes of silicon carbide furnace tube (pipe, square pipes, flat tubes, horseshoe-shaped tubes), furnace, oven batteries, furnace lining, furnace floor, and tunnel muffle kiln insulation panels, Furnace Road, rail, roller sets, all kinds of experimental furnace lining and high-temperature furnace used§, push the board moved into the board

三。碳化硅制品：具有优良的导热性、高温热稳定性好、较高的荷重软化点及很高的耐磨性，专业制作各种形状的碳化硅炉管(圆管、方管、扁管、马蹄形管)、炉膛、炉芯、炉衬、炉底板，马弗炉及隧道窑隔热板，加热炉的道轨、辊套，各种实验电炉内衬以及高温窑炉用匣钵、推板移进板

On the basis of the existing sieving method of sieving thyratrons, serving the typical fuze detonating circuit as the circuit of sieving thyratrons, and applying the operation conditions of the typical fuze detonating circuit in the sieving circuit, we can measure more accurately the turn on voltage, trigger voltage, turn on time, and leak of electricity of the thyratrons.

在现有闸流管检测方法的基础上，将实际的引信起爆电路作为闸流管的检测电路，将起爆电路的工作条件施加于检验电路，可以更准确地给出闸流管的导通电压、触发电压，同时测量出闸流管的导通时间以及闸流管在关断状态下的漏电流。

Water inside vacuum heat- collection tubes; since the hot medium inside vacuum tubes floats up and cold one goes down due to respective specific gravity, hot and cold mediums convections up and down to cause the heat conduction, furthermore transfer the heat to the related working medium in the heat tubes, the working medium sorbs the potential heat and becomes steam to rise up to the condensing section from the tube heat evaporating section; it emits the heat in condensing section to change again into liquid working medium; it flows back to evaporating section under the gravity action, the emitted heat is transferred into the water inside water tank or tube group by means of the heat-conduction through heat tubes condensing section; it makes the cold water in water tank into hot water in the repeated way.

阳光透过全玻璃真空集热管的外玻璃，照射到涂覆在内玻璃管外表面的选择性吸收涂层上，涂层将太阳的辐射能吸收并转化为热能，通过内玻璃管壁导热，传递给真空集热管内其液态传热介质，由于真空集热管内热的介质因比重小而上浮，冷的介质因比重大而下沉，冷热介质上下对流传热和导热，再通过热管的金属壁导热，将热量传递给热管内其相变工质，工质吸收汽化潜热而变成蒸汽，由热管蒸发段上升到冷凝段，在冷凝段放热冷凝，又变成液态工质，在重力作用下流回蒸发段，所放出的热量通过热管冷凝段金属管壁导热，传递给水箱或联集管内的冷水，周而复始，于是便将水箱内的冷水全部加热成热水。

Taking one kind of specification boiler pipe as the object of study, the cracking parent metal, the cracking fragment and the primary goods were analyzed by vertical and horizontal directions.

以某种规格锅炉炉管为研究对象，在炉管爆裂处的母材、撕裂碎块以及供货原材料的纵横两个方向分别取样进行分析，探讨锅炉管爆裂处的金相变化对炉管失效的影响，并给出锅炉炉管爆裂破坏的金相学原因。

The tubing fabric ,the anti-seepage film and the resin and the composite technology are introduced,and the different application performance of the tubing plain weave,tubing weft pile weave and tubing warp knitting is analyzed.

阐述了管状织物、防渗膜及树脂材料的选择及其复合工艺，分析了管状平纹织物、管状纬起绒织物和管状经编针织物的不同应用性能，也对管状纺织复合材料进行了物理性能与耐化学腐蚀性能测试。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了