Emissivity Measurements on Metallic Surfaces with Various Degrees of Roughness: A Comparison of Laser Polarimetry and Integrating Sphere Reflectometry

Both integrating sphere reflectometry (ISR) as well as laser polarimetry have their advantages and limitations in their ability to determine the normal spectral emissivity of metallic samples. Laser polarimetry has been used for years to obtain normal spectral emissivity measurements on pulse-heated materials. The method is based on the Fresnel equations, which describe reflection and refraction at an ideally smooth interface between two isotropic media. However, polarimetry is frequently used with surfaces that clearly deviate from this ideal condition. Questions arise with respect to the applicability of the simple Fresnel equations to non-specular surfaces. On the other hand, reflectometry utilizing integrating spheres provides a measurement of the hemispherical spectral reflectance, from which the normal spectral emissivity can be derived. ISR provides data on spectral-normal-hemispherical reflectance and, hence, normal spectral emissivity for a variety of surfaces. However, the resulting errors are minimal when both the sample and the reference have a similar bidirectional reflectance distribution function (BRDF). In an effort to explore the limits of polarimetry in terms of surface roughness, room temperature measurements on the same samples with various degrees of roughness were performed using both ISR and a laser polarimeter. In this paper the two methods are briefly described and the results of the comparison are discussed.     

Combinatorial pulsed laser deposition and thermoelectricity of (La1−xCax)VO3 composition-spread films

La_1−xCa_xVO₃ composition-spread film library was fabricated by combinatorial pulsed laser deposition and their thermoelectric properties were evaluated paralelly by the multi-channel probes of Seebeck coefficient and electric conductivity. Concurrent X-ray analysis verified the formation of solid soluted films in the full composition range (0x1) as judged from the linear variation of the lattice constants. The Seebeck coefficients of La_1−xCa_xVO₃ changed from a large negative value to almost zero with the increase of x, due presumably to the variation of valence in vanadium ions.The power factor in this library was as high as 0.6 μW/cm K², which was obtained at x=0, i.e. pure LaVO₃ grown at 800 °C.     

基于Petri网研究选择性拆卸

废弃产品的拆卸回收是绿色制造中的关键技术。运用Petri网作为数学工具描述产品的拆卸树，并用自定义的语法作形式化的表达，重点研究了选择性拆卸问题。这对于废弃产品的回收、重用以及日常的维修，都具有重要作用。基于拆卸Petri网，提出了两种评价函数，并运用反向启发式搜索策略，形成了一个改进型的算法。最后对一个工程实例作了具体研究，验证了方法的可行性，使得选择性拆卸序列具有供现场机器人实用的价值。     

干涉型光纤水听器相位载波解调技术

通过数学推导和仿真分析,对直接调制光源产生相位载波的马赫-曾德尔(Mach Zehnder)干涉型光纤水听器调制解调技术进行了研究。提出了不能通过干涉信号的峰值或峰峰值检测来控制自动增益控制(AGC)电路增益的方法消除偏振衰落对输出信号的影响。在这一思想的指导下完成了光纤水听器相位载波(PGC)解调电路的设计,给出了实验测试结果。     

用于液体粒子计数的PIN光检测传感器的设计

设计了用于液体粒子计数的PIN光检测传感器,介绍了光散射式粒子传感器的工作原理及其光学检测系统构成,并且对其放大电路的原理做了具体的分析。理论和实践证明:这种新型光检测传感器具有信噪比高、体积小、灵敏度高、测量准确,抗干扰能力强、能耗低等特点,可识别的粒径范围为0.1～10μm,尤其适用对液体中微粒光散射信号的有效检出与在线监测。     

分布式存储环境下的加性Schwarz方法

引言 区域分裂方法起源于古老的schwarz交替方法[l].八十年代末期,法国数学家P.L.LionS提出了schwarz交替方法的投影解释[2一4],使得人们对schwarz交替方法有了全新的认识,为其进一步发展奠定了理论基础.由于并行计算环境的逐渐成熟以及预处理技术的兴起和大规模科学计算的需要,由严格串行的scliwarz交替方法发展了多种可完全并行的     

Partner Selection for Strategic Alliance in Networked Manufacturing

Networked Manufacturing is the trend evolution for manufacture enterprise to gain core competence in the networked economy environment. In this paper, the definition of the strategic alliance is introduced and its life cycle is described. As the selection of suitable partners is of vital importance to the success for strategic alliance in Networked Manufacturing environment, also in this paper, the definition, criteria and process for partner selection are introduced. Then the fuzzy-AHP (Analytic Hierarchy Process) method, as a fuzzy extension of analytic hierarchical approach for partner selection, is given. In the end, a case study is provided.     

Comparison of OR and AI methods in discrete manufacturing using fuzzy logic

Since 1950s the techniques of Operations Research (OR) and Optimization have been utilized to increase the efficiency of the production systems. With the widespread use of computers, it has even become easier to deal with industrial problems. However the complexity of the problems still reveals the difficulty in providing solutions. The use of artificial intelligence (AI) seems to attract the attention of the researcher to overcome to the difficulties. This has already been realized with several successful applications. In this study, the use of AI and OR techniques is compared using fuzzy logic. The progress of manufacturing systems, characteristics of production processes, system managements and system behavior are taken into account. The study is focussed on only discrete manufacturing.     

Sensitivity Analysis for Scheduling Problems

This paper represents a first attempt at a systematic study of sensitivity analysis for scheduling problems. Because schedules contain both combinatorial and temporal structures, scheduling problems present unique issues for sensitivity analysis. Some of the issues that we discuss have not been considered before. Others, while studied before, have not been explored in the context of scheduling. The applicability of these issues is illustrated using well-known scheduling models. We provide fast methods to determine when a previously optimal schedule remains optimal. Other methods restore an optimal schedule after a parameter change. The value of studying the sensitivity of an optimal sequence instead of the sensitivity of an optimal schedule is demonstrated. We show that, for some problems, sensitivity analysis results depend on the positions of jobs with changed parameters. We identify scheduling problems where performing additional or different computations during optimization facilitates sensitivity analysis. To improve the robustness of an optimal schedule, selection among multiple optimal schedules is considered. We discuss which types of sensitivity analysis questions are intractable because the scheduling problem itself is intractable. We also study how heuristic error bounds vary when the data of a scheduling problem is continuously modified. Although we focus on scheduling problems, several of the issues we discuss and our classification scheme can be extended to other optimization problems.     

Examination of microhardness indentation-induced subsurface damage in alumina platelet reinforced borosilicate glass using confocal scanning laser microscopy

Borosilicate glass and borosilicate glass matrix composites reinforced with 10, 15 and 30 vol.% alumina platelets have been indented and the subsurface lateral cracking examined by confocal scanning laser microscopy (CSLM). The suitability of the CSLM technique as a quick and nondestructive method of obtaining three-dimensional information of subsurface damage in dispersion reinforced brittle matrix composite materials was demonstrated. The addition of alumina platelets to the glass matrix has resulted in a reduction in the extent and depth of subsurface damage due to indentation, and hence may make the material more resistant to erosive wear. This damage development may be a consequence of the presence of residual compressive stresses in the matrix and the strong platelet/matrix interfacial bonding.