Performance of natural‐fiber–plastic composites under stress for outdoor applications: Effect of moisture,temperature, and ultraviolet light exposure

The effects of moisture, temperature, and ultraviolet (UV) light on performance of natural‐fiber–plastic composites (NFPC) were assessed. We conducted short‐term tests in the laboratory and long‐term tests under natural exposure and measured changes in mechanical properties and color in samples of the composite. Chemical changes of the composite's materials were measured by X‐ray photoelectron spectroscopy to elucidate the mechanisms of chemical transformations on the material surface. Relative humidity highly affected the modulus of rupture (MOR) and the modulus of elasticity (MOE), and had a greater effect than temperature and UV exposure on performance of the composite. The lightness of the composite was increased by the UV effect in the short‐ and the long‐term tests. The X‐ray photoelectron spectroscopy (XPS) analysis suggested that the composite was protected by the UV absorber. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2570–2577, 2006     

关于从旋涡炉渣回收铜的研究

介绍了用自然澄清法降低、回收旋涡炉渣中的铜的方法。该方法工艺简单。操作方便，不仅降低冶炼成本，同时提高了经济效益。     

热镀锌工艺对Ti-IF钢光整热镀锌板组织和性能的影响

在连续热镀锌线上研究了RTH带钢温度和光整延伸率对Ti—IF钢光整热镀锌板组织和性能的影响。试验表明，当RTH带钢温度在830℃以下时，成品铁素体晶粒度为10．0级，织构类型以{332}、{114}为主，随着带钢温度的进一步提高，热镀锌板的晶粒逐渐粗化，织构成为典型的{111}织构，且取向密度增加，r值随之提高，但当带钢温度在900℃以上时，织构又趋于无规则分布，r值显著降低；光整延伸率对Ti—IF钢光整热镀锌板力学性能的影响很大，随着光整延伸率的提高，屈服强度明显提高，n值明显降低，延伸率降低，抗拉强度变化较小，且光整延伸率对性能的影响与成品铁素体晶粒尺寸有关，成品晶粒越粗，光整延伸率的影响越大。因此对于Ti—IF钢光整热镀锌板而言，n、r值是一对矛盾体，在制订热镀锌工艺时，需根据使用条件的不同，对其n、r值进行综合考虑。     

水喷雾灭火系统在电信枢纽工程燃气锅炉房的应用

分析了燃气锅炉的火灾危险性和水喷雾用于燃气锅炉消防的灭火机理,提出了水喷雾灭火系统的设计参数的选择、系统的控制方法以及在设计中可能涉及到的问题和注意事项,并结合工程实例进行了探讨。     

Dynamics of Vibroprotective Systems with Roller Dampers of Low-Frequency Vibrations

We study low-frequency vibrations of a vibroprotective system of solid bodies formed by a roller damper and a moving load-carrying body under the action of external harmonic excitations. The dynamic equations of combined motion of the working body of the damper over the hinged roller without sliding and the load-carrying body are deduced and numerically analyzed. A new procedure is proposed for the evaluation of the optimal parameters of adjustment of roller dampers in nonlinear systems.     

国产螺旋槽密封在进口压缩机上的应用

介绍了国产螺旋槽密封在进口压缩机上的应用，分析了原进口机械-浮环组合密封的失效原因，叙述了改造后国产浮环螺旋槽组合密封的结构和特点。     

Controllability of One Spin and Two Interacting Spins

Mathematics of Control, Signals, and Systems - ?We consider the problem of steering control for the systems of one spin ½ particle and two interacting spin ½ particles in an...     

铁液洁净度对凝固热力学参数的影响

为了给高洁净钢连铸细晶技术提供相关理论依据，在高温钼丝炉中通过对电解纯铁加金属铝和硅脱氧，获得不同铁液洁净度的试样。利用差热分析法测定了试样在相同冷却速度下的过冷度。利用凝固过程热力学理论研究了铁液洁净度与过冷度、凝固热力学驱动力、形核功和临界晶核半径等的关系。结果表明：随着铁液洁净度的提高，铁液凝固时的过冷度增大，形核所需的凝固热力学驱动力变大，非均质形核功和临界晶核半径减小。     

Singular Trajectories in Multi-Input Time-Optimal Problems: Application to Controlled Mechanical Systems

This paper deals with the time-optimal control problem for a class of control systems which includes controlled mechanical systems with possible dissipation terms. The Lie algebras associated with such mechanical systems have certain special properties. These properties are explored and used in conjunction with the Pontryagin maximum principle to determine the structure of singular extremals and, in particular, time-optimal trajectories. The theory is illustrated by an application to a time-optimal problem for a class of underwater vehicles.     

Gleeble 3800热模拟试验机在宝钢的典型应用与功能开发

热模拟试验可研究成分与各工艺参数对组织和性能的影响，用于指导产品设计和实际生产工艺的制定，还有助于建立数学模型。文章介绍了Gleeble 3800热／力模拟试验机在宝钢实际应用中的几个典型试验，包括高温热塑性试验、多道次变形试验、冷轧薄板相转变点试验和HAZ焊接热影响区热模拟试验等。这些试验可用来解决连铸、轧钢和冷轧产品热处理生产中存在的一些问题。