12％Cr铁素体不锈钢板材显微组织特征对腐蚀性能的影响

研究了410S和409L两种铁素体不锈钢板材热轧态显微组织特征、晶间腐蚀特征以及在6％FeCl3酸性腐蚀介质中的浸泡腐蚀特征.结果表明,410S在6％FeCl3酸性腐蚀介质中为分层腐蚀,409L则为均匀腐蚀.410S在0.5 moFL H2SO4+ 0.01 mol/L KSCN溶液中有明显的晶间腐蚀,409L没有晶间腐蚀.综合分析表明:实验用钢410S的腐蚀特征由双相组织所致,而409L主要是由于Ti元素的添加使得碳化物的析出减少.     

Degradation of permeability resistance of high strength concrete after combustion

To evaluate the remaining durability of concrete materials after combustion, the permeability of high strength concrete (HSC) after combustion was studied. The transport behavior of chloride ion, water and air in concrete after combustion and the effect of temperature, strength grade, and aggregation on the permeability of HSC after combustion are investigated by chloride ion permeability coefficient (D_c), water permeability coefficient (D_w) and air permeability coefficient (D_a). The experiment results show that all three permeability coefficients commendably reflect changes of permeability. The permeability coefficient increases with the evaluation temperature. After the same temperature, the permeability coefficient of HSC is lower than that of normal strength concrete (NSC). However, the degree of degradation of permeability coefficient of HSC is greater than that of NSC. The permeability resistance of HSC containing limestone is better than that of HSC containing basalt. Combining changes of compressive strength and permeability, the remaining durability of concrete materials after combustion is appropriately evaluated.     

卡车转向轻便性仿真分析与评价技术

讨论了操纵装置力学特性的人机工程学要求。针对卡车转向沉重问题,应用ADAMS/Car建立了卡车整车多体动力学模型,并进行了转向轻便性仿真试验。仿真分析结果表明,卡车转向盘力输入特性满足人机工程学设计要求,具备较好的转向轻便性。     

Experimental Investigation of Capacity Control Scheme on System Performance for a Machine Tool Cooler

Highly accurate manufacture in machining industry can only be obtained with precise temperature control of the coolant (oil or water).Machine tool with more accurate,stable and advanced the precision of the working component cannot be developed without appropriate cooling.However,the machine tool coolers are facing the control hunting of cooling temperature and the dramatic variation of heat load in high-accuracy machining.The main objective of this study is to evaluate the influence of the hot-gas by-pass scheme and suction regulation for capacity control of a machine tool cooler system.In this study,experimental investigation on both hot-gas by-pass scheme and suction valve regulation for capacity control has been proposed.Effects of using capillary tube and thermostatic expansion valve along with different capacity control scheme have been investigated extensively in an environmental testing room.Cooling performance and power consumption of the cooler system have been measured and analyzed as well by comparing with different opening percentage of throttling valve under specific coolant temperature.The experimental results reveal that the power consumption will reduce slightly by capacity control using the hot-gas by-pass scheme but the coefficient of performance (COP) of the overall system will decrease.Lower coolant temperature will result in higher compressor power consumption as well.While conducting suction valve regulating for capacity control,energy-saving at 10%-12% can be obtained by using thermostatic expansion valve under different evaporator load.It also reveals that suction valve regulation along with adequate choice of thermostatic expansion valve can provide alternative choice for steady capacity control and substantial energy-saving.The proposed cooler systems with different capacity control schemes are not only more cost-effective than inverter driven system,but also can perform energy-saving and precise temperature control specific for high-accuracy machine tool cooling.     

冷冻工法之风险管理暨施工案例探讨

潜盾隧道挖掘工法为目前台北都会区捷运系统地下隧道所普遍采用的施工方法之一,除具有安全、经济的特性外,对于施工中交通维持亦较具优势.然而,在都会区人口发展密度逐渐升高的今日,潜盾机发进及到达的工作井深度亦越来越深.除传统之地盘改良工法,以高压喷射灌浆置换软弱土壤外,因施工需要而必须辅以大规模冷冻工法形成相当厚度之冷冻帷幕以阻绝地下水流,达到"增幅防御"施工安全的目标.文中以台北捷运新庄线CK570C标为案例介绍冷冻工法在施工过程中的相关风险管理与探讨.     

设计悟道--浅议道家思想与现代艺术设计

以道家思想为依托,将道家的理论置入新兴的艺术设计领域,剖析现代艺术设计与传统思想的接壤,从形式和功能、技术和艺术、简洁和繁复的对比中探讨理性的设计思维,总结传统美学应用于现代社会的一些规律.     

基于复合相变储能材料的研究进展

相变储能材料具有储热密度高,储热过程中温度变化非常小的优点。相变储能材料已广泛应用于热泵、太阳能利用等领域。本文综述了近些年来复合相变储能材料的研究状况,包括相变储能材料的制备、传热强化、相变过程数值模拟和应用等,并对复合相变储能材料的发展作了展望。     

A SEQUENTIAL QUADRATIC PROGRAMMING ALGORITHM UTILIZING QR MATRIX FACTORIZATION

Some recent studies indicate that the sequential quadratic programming (SQP) approach has a sound theoretical basis and promising empirical results for solving general constrained optimization problems. This paper presents a variant of the SQP method which utilizes QR matrix factorization to solve the quadratic programming subproblem which result from taking a quadratic approximation of the original problem. Theoretically, the QR factorization method is more robust and computationally efficient in solving quadratic programs. To demonstrate the validity of this variant, a computer program named SQR is coded in Fortran to solve twenty-eight test problems. By comparing with three other algorithms: one multiplier method, one GRG-type method, and another SQP-type method, the numerical results show that, in general, SQR as devised in this paper is the best method as far as robustness and speed of convergence are concerned in solving general constrained optimization problems.     

回转窑内气体和物料温度分布的研究

为进一步探索回转窑的优化设计及经济运行情况,在已有的回转窑传热研究的基础上,将其内部的传质过程与对流、辐射、传导3种热交换方式相结合,建立了计算回转窑温度分布的综合数学模型,预测了窑内烟气、物料及窑内壁的温度分布,并对某厂回转窑进行数值计算.结果表明:在距窑头约14m处,气体温度达到最高值,约为1760℃,物料温度约为1465℃,随后气体和物料温度沿窑长逐渐下降,到达窑尾处时分别降至约1028℃和856℃.计算结果与实际运行结果吻合较好,说明该模拟方法具有一定适用性.     

Analysis of operating policies for manufacturing cells

We present an analytical model for error-recovery problems of unitary production cells and develop a framework for economic justification. Each production cell has its own machine and functional characteristics (e.g. precision, speed, operating cost). Each alternative operating policy of error-recovery for a production cell leads to a different system throughput, scrap rate, and required quantities of parts. However, error recovery cannot be accomplished without in-process inspections. Thus, the central problem discussed in this paper is to maximize profits or throughput rate by selecting an appropriate production cell along with an optimal set of inspection and error recovery policies.