硬泡沫塑料的力学性能分析:压缩弹性模量分析与计算机摸拟

对包装行业中常用的一类包装材料—硬泡沫塑料的压缩弹性模量的估算方法进行了探讨，发展了以力学模型为基础的随机模拟方法。以PUR发泡硬泡沫塑料为例，将此方法的计算结果与试验数据进行了比较。本方法既反映泡沫塑料的结构的力学性质，又体现了结构参数的随机特征，并且算法简单，编程容易，耗机时小，利于工程应用。     

半导体制冷冰箱的研究

主要介绍以半导体器件为制冷源的新型绿色食品冰箱.采用帕尔贴效应的制冷方法,使其具有换气、除臭、冷藏、冷冻、食品保鲜等多项功能.该冰箱无污染,制冷速度快,噪声低,具有潜在的市场开发前景.     

等离子束熔覆技术在缸体缺陷修复中的研究

针对液压支架缸体的使用条件,采用等离子熔覆技术修复其表面缺陷,在27SiMn钢基体上熔覆合金粉末,形成金属基复合材料熔覆层.该熔覆层硬度可达1433 HV.该熔覆层与基体形成的冶金结合体具有较高的耐磨性能.应用结果表明,经熔覆处理,缸体使用寿命提高3～5倍,达到了良好的效果.     

碾压混凝土围堰爆破拆除倾倒过程数值模拟研究

对碾压混凝土围堰爆破拆除用动力有限元程序进行了数值模拟。计算分析了廊道对爆破拆除的影响,并对爆破缺口和整体倾倒过程进行了模拟。研究表明:有廊道时由于自由面多,药室起爆后引起的振动速度峰值比没有廊道时要小得多,这对拟保留体是有利的。有廊道时爆破缺口比较规则,近似为梯形,所有药室起爆后能爆除残留根底,缺口顶部和底部无突出块,利于整体倾倒,符合爆破设计要求。计算结果和爆破设计方案相吻合,证明了爆破设计方案的合理性和可行性。     

ZL114A合金旋转喷吹精炼工艺研究

采用旋转喷吹精炼工艺精炼ZL114A合金,通过选择设备不同的喷头转速、气体流量,确定了最佳的设备参数.研究了金属液中氢含量随精炼时间的变化规律,确定了ZL114A合金的旋转喷吹精炼工艺参数;比较了精炼前后镁含量的变化,并测试了旋转喷吹精炼后合金的性能.结果表明,采用旋转喷吹精炼工艺精炼前后镁含量的变化很小,合金熔体纯净度高,合金的性能较高.     

用Alu－VectorettePCR方法从酵母人工染色体末端分离人基因组单拷贝片段

分离和克隆ＹＡＣ插入片段的末端顺序是构建ＹＡＣ重叠群的重要手段之一，我们采用Ａｌｕ载体（Ａｌｕ－ｖｅｃｔｏｒｅｔｔｅ）ＰＣＲ方法成功地从含人淀粉样蛋白前体（ＡＰＰ）基因的法国人类多态研究中心（ＣＥＰＨ，Ｃｅｎｔｒｅｄ＇ＥｔｕｄｅｄｕＰｏｌｙｍｏｒｐｈｉｓｍｅＨｕｍａｎ）ＹＡＣ克隆５９９Ｇ１１的未端分离到一个０．５８ｋｂ的单拷贝片段。测序后经核普酸顺序检索分析，证明这是一个新的ＳＴＳ顺序。用这个片段作探针，在英国肿瘤研究基金会（ＩＣＲＦ）的ＹＡＣ库中筛选到一个新的ＹＡＣ克隆，证明这是获得ｃｏｎｔｉｇ的有效而快捷的方法。     

枢纽港—物流港联动的罗泾港区规划设计创新

新近建成的上海港罗泾港区是集矿石、煤炭、钢铁等散杂货物为一体的综合性港区,是世界上第一座公共港区为大型钢铁企业提供分拨配送等增值服务的物流港区。罗泾港区规划设计开发了全新的“枢纽港—物流港”联动的平行结构平面布置模式。在传统的公用港口布置方法基础上,运用准时制（JIT）的精益生产（LP）物流理念,优化装卸工艺和港口平面布置,提升服务水平,延伸港口服务链条;实现了物流流程的高度一体化、同步化;节约了极为宝贵的深水岸线和土地资源、降低了能耗。     

A linear theory for bending stress-strain analysis of a beam with an edge crack

In this paper, a new linear theory for bending stress-strain analysis of a cracked beam has been developed. A displacement field has been suggested for the beam strain and stress calculations. The bending differential equation for the beam has been written using equilibrium equations. The required constant for this model is also obtained from fracture mechanics. The bending equation has been solved for a simply supported beam with rectangular cross-section and the results are compared with finite element and empirical results. There is an excellent agreement between theoretical results and those obtained by numerical and empirical methods. The model developed in this research is a simple and precise approximation of the behavior of the cracked beams in bending.     

Two-Phase Flow of Blood with Magnetic Dusty Particles in Cylindrical Region: A Caputo Fabrizio Fractional Model

The present study is focused on the unsteady two-phase flow of blood in a cylindrical region. Blood is taken as a counter-example of Brinkman type fluid containing magnetic (dust) particles. The oscillating pressure gradient has been considered because for blood flow it is necessary to investigate in the form of a diastolic and systolic pressure. The transverse magnetic field has been applied externally to the cylindrical tube to study its impact on both fluids as well as particles. The system of derived governing equations based on Navier Stoke’s, Maxwell and heat equations has been generalized using the well-known Caputo–Fabrizio (C–F) fractional derivative. The considered fractional model has been solved analytically using the joint Laplace and Hankel (L&H) transformations. The effect of various physical parameters such as fractional parameter, Gr, M and γ on blood and magnetic particles has been shown graphically using the Mathcad software. The fluid behaviour is thinner in fractional order as compared to the classical one.     

Analysis of Film Condensation Along a Vertical Flat Plate Under Sinusoidal G-Jitter

Transient phenomenon of laminar film condensation along a vertical flat plate under sinusoidal g-jitter has been analyzed, based on the same assumptions of Nusselt’s analysis of film condensation where the heat transfer within the liquid film is by pure conduction. The momentum equation retains the transient term. The perturbed acceleration due to gravity has been assumed to be a sinusoidal function of time and frequency of oscillation for the simplicity. The resultant equation has been solved analytically and the velocity profiles and mass flow rate under such g-jitter has been simulated. It has been observed that at the different heights the velocity response with time is purely sinusoidal with different amplitude. Last but not the least; boundary layer thickness is also oscillating with time, hence heat transfer coefficient. However, the entire analysis is an extension of Nusselt’s analysis of film condensation which includes transient response.     

波浪作用下抛石潜堤的动态稳定数值模拟

抛石潜堤在港口工程中得到广泛应用, 该文运用离散单元法中的二维颗粒流方法建立了抛石潜堤模型, 分析了刚度和摩擦系数两个细观参数对模型分析的影响。结合工程实例, 合理确定了抛石潜堤颗粒流模型的细观参数, 克服了传统连续介质力学的宏观连续性假设, 形象而直观的模拟分析了抛石潜堤的动状稳定破坏。研究表明, 在波浪荷载作用下, 抛石重量是影响失稳的主要因素, 其次是堤顶宽度及断面坡度。抛石重量越大, 堤顶宽度越大, 断面坡度越缓, 则抛石潜堤的整体稳定性越好。应用此结论, 针对该工程, 对抛石潜堤进行了结构优化, 得到不同的抛石块体以及不同的断面形状的优化潜堤结构。     

数据中心自然冷却技术研究进展

数据中心的能耗增长日益受到关注,其能耗的很大部分是用于机房冷却。采用节能冷却方法是节能减排的迫切要求,自然冷却技术是其中的有效方法之一。自然冷却技术的实施有三种主要方式:空气侧自然冷却、水侧自然冷却和热管自然冷却。空气侧自然冷却简便易行且节能效果好,但会影响室内空气质量和湿度。水侧自然冷却可以在原有的空调机组上改造实现,但由于增加了中间传热过程其节能效果有限。热管自然冷却避免了对室内环境的影响,且同时利用相变传热节能效果较好。本文总结了近年来这三种自然冷却技术的最新进展,为这一领域的研究提供参考。     

Detector for trace amounts of nitrogen in helium

A detector has been developed which can detect very low levels of contamination in a gaseous process stream or storage vessel. The detection is based on the emission spectrum of the gas in a low current electrical discharge. The system has proven very useful for helium liquefier operation and has been used extensively at Fermilab to monitor contamination of helium by nitrogen, water and hydrocarbons. Specifications of the unit in use at the Fermilab Central Helium Liquefier are included, as well as schematic drawings which define the critical configurations. A summary of the results of studies on various wavelengths and substances is included. The system is very reliable, stable, sensitive, and easy to maintain and operate. The output signal is specific to the substance which has optical emission at the wavelength of the monochromator setting.     

Mathematical description of the mechanical behaviour of metallic materials under creep conditions

The metallic materials creep behaviour has been described and a complete model is presented. The basic constitutive equation, as well as the structure parameters, have been derived from a mathematical analysis that represents the dominant physical procedures and mechanisms. The model is very general because it is referred to all stages of creep and describes the creep behaviour of all metallic materials, including those strengthened by a dispersion of second-phase particles. A creep function has been derived from the constitutive equation describing all three stages of creep under constant loading. The function has the minimum possible number of fitting, parameters. The dependence of the fitting parameters on the loading conditions has been described using very simple mathematical relations. Applications and predictions have been carried out in a wide range of metallic materials. Good agreement has been shown by a comparison made also between the creep curves determined experimentally, and those obtained from creep function and determined fitting parameters.     

On propagation of shear waves in a multilayer medium including a fluid-saturated porous stratum

Summary The propagation of SH-type waves in a double surface layered medium with an intermediate transverse-isotropic fluid-saturated porous stratum has been examined. The top-most layer is assumed to be impermeable, elastic, homogeneous and isotropic, whereas the lower half-space is a nonhomogeneous one. The dispersion equation has been derived using the Biot's theory for the porous layer and the theory of elasticity for both the upper and the subjacent half-space.The corresponding dispersion equation for the simplified case where the dissipation caused by the relative fluid flow has been omitted has also been obtained. The numerical results obtained for this simplified case have been shown graphically.With 5 Figures     

MMA/EMA/EA胶乳型互穿网络聚合物阻尼特性研究

用乳液聚合的方法制备了MMA/EMA/EA的LIPN ,对其阻尼特性进行了研究 ,并研究了增塑剂和填料对其阻尼性能的影响。结果发现 ,此LIPN具有良好的阻尼特性 ,增塑剂的加入对其阻尼特性影响很小。而不同的填料对其阻尼特性的影响不同。其中具有球状立体结构的富勒烯的加入会使其阻尼性能得到大幅度提高     

液化天然气(LNG)储存容器中的分层与翻滚

针对储罐中液化天然气（LNG）在温度差和密度差下的分层行为，建立LNG分层的异重流模型。并利用Lorenz方程描述异重流下层的热对流状态。采用耦合映象格子模型求解Lorenz方程，并引入对流强度量判断系统分层涡旋的产生和发展。对系统的数值模拟研究，确定了系统处于独立循环、分层翻滚及对流循环状态时对应的瑞利数Ra临界值。证明了系统在密度差趋于相等时，分界面被打破，LNG大量蒸发出现分层翻滚现象；并得到了系统随主要控制参数Ra的发展过程及分层翻滚发生的时间、高峰蒸发量等。计算表明：对于给定的密度差和温度差，底层的LNG厚度越大，则出现翻滚现象的时间越迟；底层厚度越大，高峰蒸发速度也越大，较易引发储罐超压；对于给定温度差，底层LNG密度较大时，出现翻滚的时间会相对提前。     

静止轨道高分辨率光学遥感探索

为了实现地球静止轨道高分辨率光学遥感,研究了在运载的动力学环境上与低轨的差异。分析了主动飞行段时间长、力学环境差、在成像方法上采用面阵成像、轨道高等原因使相机体积增大的问题。对静止轨道21.5m分辨率模拟相机进行了研究,开展了动力学模拟试验,得到了相机关键部位的测试参数,证明了地球静止轨道高分辨率光学遥感的核心环节即有效载荷研制的可行性。     

A Radiation-Hardened Fiber-Optic Transmission System Having a 400-MHz Bandwidth and Linear Response

A radiation-hardened fiber-optic signal transmission system has been built that has a bandwidth of over 400 MHz with linear response. An amplitude-modulated CW laser diode is used in the transmitter. Automatic bias compensation is applied to the laser in lieu of the typical temperature control. The system has provision to remotely select (via a fiber-optic control link) the attenuation between the signal input and the transmitter. A self-contained system-calibration pulse is also remotely triggerable. The transmitter has a volume of about 75 in3, including the battery power supply. The rise time of the system is 1.2 ns and the dynamic range is 35 dB. The transmitter and fiber-optic portions of the system are hardened to withstand a photon irradiation of more than 5 × 105 rad(Si)/s from a Febetron 705.     

用于壳体自由振动分析的广义协调元

本文采用基于解析试函数的广义协调四边形膜单元和中厚板单元构造了平板型4节点壳体单元,并将其用于壳体振动分析。该壳体单元具有列式简单,易于编程的优点,通过数值算例表明,该单元计算精度高,非常适合工程计算