Numerically optimal design for the system with coupled complex transport phenomena-application to the Submerged Entry<Emphasis Type="Italic">Nozzle</Emphasis> in continuous slab caster

This study presents a simple and robust algorithm for the optimal design of the system with coupled complex transport phenomena: the transport phenomena comprise fluid flow, heat and mass transfer. The (1+1)-Evolution Strategy method is adopted as the optimization method. In order to analyze the transport phenomena in the complex geometry generated during the optimization procedure, thefinite volume method with a boundary fitted curvilinear coordinate system is used. To confirm the validity of the present method, the optimal design for the inner shape of the simplified two-dimensionalSubmerged Entry Nozzle in the continuous slab caster is conducted. It is shown that the resulting design of the nozzle is consistent with the purpose and constraints of the design.     

The Structure Stability of Carbide-Free Bainite Wheel Steel

Metallographic structures of carbide-free bainite steel wheel rim are mainly composed of supersaturated lath ferrite and retained austenite film among bainitic ferrite laths. It is suspected that supersaturated ferrite and retained austenite are likely to decompose under the influence of temperature change and mechanical stress. Stability of wheel rim structure is studied by means of x-ray diffraction, dye microscopy, and micro-hardness test. When the samples are tempered in the range of 150-350 °C, the retained austenite films are at the state of relative stability. Fifty percent of retained austenite is decomposed when the sample is tempered at 400 °C. Microhardness increases when the sample is tempered at 150 °C. The decrease in hardness is mild when the samples are tempered from 200 to 500 °C. The mechanical stability of retained austenite film is studied with tensile sample under the effect of tensile stress. The retained austenite appears to be stable in low and middle degree of deformation, and decomposition occurs at great amount of deformation. Diffraction peak of carbide is not found in all above experiments. The steel enriched silicon prevents the carbide precipitation during the transformation. It indicates the carbide-free bainite wheel steels have an excellent thermal and mechanical stability.     

基于有限元的大型铝型材拉伸矫直设备设计方法研究

介绍了大型铝型材拉伸矫直设备的研究现状,分析了现有拉伸矫直设备的缺点,提出并设计了新型的大型铝型材拉伸矫直设备。采用有限元数值模拟方法,对大型铝型材拉伸矫直机的关键零部件受力变形状况进行了数值模拟,得到了设备关键零部件如拉伸头、移动横梁等的应力和应变分布情况,并对结构进行了优化。此种方法降低了设备制造成本,提高了设备的精度和刚度。生产实践表明:采用此方法设计的拉伸矫直机运行平稳可靠。     

Influence of the stress,strain, and temperature on the surface roughness of an AlSl 52100 steel due to an orthogonal cut

In recent years, the finite element method (FEM) has become the main tool for simulating the metal cutting process because research based on trial and error is time consuming and requires high investment. Early studies were done by different investigators. In this research AISI 52100, hardened steel (62 HRC) was selected for an orthogonal machining process as well as metal cutting simulation using the software DEFORM-2D. This software is based on a forging process and has been adapted to an orthogonal machining process. The results of simulated cutting forces were compared with experimental cutting force data to validate the orthogonal cut simulation. Also, the surface roughness was measured, and the influence of the stress, strain, and temperature on the surface roughness was studied.     

1—HBTA对钢,黄铜的缓蚀作用

研究在3％NaCl水溶液和模拟冷却水介质中,不同pH值时不同浓度(0.05％、0.1％、0.5％)的1-羟基苯骈三氮唑(以下简称1-HBTA)对钢、黄铜的缓蚀作用,1-HBTA是一种阳极型缓蚀剂,对金属腐蚀的阳极过程有明显的阻滞作用,而对阴极过程影响不大。     

原位生成Al2O3、TiB2和Al3Ti/Al复合材料的热循环行为

本文研究了Al-TiO2-B系原位生成Al2O3、TiB2和Al3Ti/Al颗粒增强铝基复合材料的热循环行为，研究结果表明了纯铝及B／TiO2摩尔比分别为0、1和2的颗粒增强铝基复合材料的热循环行为具有以下结果，纯铝和复合材料热循环后均产生了残余应变和滞后环；Al-TiO2-B系列复合材料热循环应变的各项指标均比纯铝基体大大降低，且具有较小的内耗功和较好的热稳定性，可以预测其具有较高的热疲劳寿命，热循环曲线能很好的评估复合材料在温度循环变化的环境中工作时的热稳定性和热疲劳。     

铁氮共掺杂纳米TiO2的水热法制备及其在可见光下抗菌性能的研究

以硫酸氧钛为前驱体，硝酸铁和盐酸胍作为掺杂的铁源和氮源，采用水热法制备了铁氮共掺杂纳米TiO2粉体。利用XRD、BET对样品进行表征，研究了掺杂后TiO2粉体的晶型、粒径、比表面积等性能。结果表明，所制备的共掺杂TiO2粉体呈黄色，均为锐钛矿相TiO2，经谢尔公式计算其粒径约为10nm，比表面积分布为（135～150）m^2／g。采用紫外．可见光漫反射光谱对样品进行表征，结果表明经过铁氮共掺杂改性后的TiO2具有很强的紫外线的吸收能力，并实现了良好的可见光响应。采用菌落计数法进行了样品抗菌性能的研究，在可见光照射下样品对大肠杆菌表现出良好的杀灭性能。     

Surface Chemical Modification of Poly(Methylphenylphosphazene)

Summary The surface reactivity of poly(methylphenylphosphazene), PMPP, and its derivatives containing silane, PMPP-SiH, and alcohol, PMPP-OH, substituents was investigated. These polymers were fabricated into films by casting from THF solutions and reactions were carried out at the interface between solid film samples and solutions. The surface of PMPP was successfully modified by deprotonation under dilute conditions followed by reactions with RMe₂SiCl [where R = CH=CH₂, and H]. While surfaces of PMPP-OH were not readily modified, those containing Si-H groups reacted with oxygen when heated and with carbon tetrachloride. The polymer surfaces were examined by contact angle measurements, attenuated total reflectance infrared spectroscopy (ATR-IR), and scanning electron microscopy (SEM). We dedicate the paper to Christopher W. Allen in recognition of his outstanding contributions to inorganic ring and polymer chemistry.     

Cu/SBA-15 as adsorbent for propane/propylene separation

Samples of mesoporous silica SBA-15 were prepared under hydrothermal conditions where Cu cations were incorporated to the structure by impregnation in order to compare the adsorption behavior in the presence and absence of this element. The adsorption/desorption equilibrium isotherms of propylene, propane, and N₂ were measured to evaluate their usefulness in the propane/propylene separation. All the adsorption isotherms of SBA-15 measured in the absence of Cu cations were described by the Freundlich equation, while the adsorption isotherms of propane on Cu/SBA-15 were better represented by the Henry equation and those of propylene were satisfactorily described by the Langmuir model in the range P < 100 Torr. The adsorption uptake of propylene increased and that of propane decreased in Cu/SBA-15 as compared to the amounts observed in the SBA-15 sample. The presence of Cu atoms in the adsorbent lattice increased the selectivity towards propylene. Under some working conditions the adsorbed amount of propylene in Cu/SBA-15 sample was totally reversible and the propane uptake, negligible.     

水基传送带润滑剂综述

说明了水基传送带润滑剂的作用机理、性能要求,详细介绍了现有的水基传送带润滑剂的特点,并简单介绍了水基传送带润滑剂的发展前景和趋势。