基于启发式Q学习的汽车涂装车间作业排序优化

针对汽车涂装车间中的作业优化排序问题,提出一种基于启发式Q学习的优化算法。首先,建立包括满足总装车间生产顺序和最小化喷枪颜色切换次数的多目标整数规划模型。将涂装作业优化排序问题抽象为马尔可夫过程,建立基于启发式Q算法的求解方法。通过具体案例,对比分析了启发式Q学习、Q学习、遗传算法三种方案的优劣。结果表明:在大规模问题域中,启发式Q学习算法具有寻优效率更高、效果更好的优势。本研究为机器学习算法在汽车涂装作业优化排序问题的应用提出了新思路。     

不同探针分子温敏漆的制备及性能对比研究

利用氯化铕(Eu Cl3)、苯甲酸(BA)、菲咯啉(Phen)和2,2′-联吡啶(Bipy)为原料合成了Eu(BA)_3Phen和Eu(BA)_3Bipy两种配合物,并将两种配合物分别掺入甲基丙烯酸甲酯(MMA)中,在过氧化苯甲酰(BPO)作用下引发聚合,获得不同探针分子的两种温敏漆Eu(BA)_3Phen/PMMA和Eu(BA)_3Bipy/PMMA。利用红外光谱、紫外吸收光谱和荧光光谱对两种探针分子及温敏漆的特性进行了表征,分析结果表明,探针分子Eu(BA)_3Phen的荧光强度明显强于Eu(BA)_3Bipy,相对应的两种温敏漆Eu(BA)_3Phen/PMMA与Eu(BA)_3Bipy/PMMA均有较好的温度猝灭特性,但是对比分析发现在25~35℃和35~45℃温度区间内温敏漆Eu(BA)_3Phen/PMMA的灵敏度较高,而在45~55℃和55~65℃温度区间内温敏漆Eu(BA)_3Bipy/PMMA的灵敏度较高,可见温敏漆在不同温度区间的测温灵敏度是不同的。     

Open spaces and molecular motions of acrylic epoxy-based network polymers probed by positron annihilation

Lifetime spectra of positrons have been measured for acrylic epoxy-based network polymers. For the specimens with the different permeability coefficients to water vapor C_p, the lifetime of ortho-positronium (o-Ps) τ₃ increased with increasing C_p. This fact suggests that the permeability increases with an increase in the size of open spaces. From measurements of temperature dependencies of τ₃ and the intensity of o-Ps, three onset temperatures for the change in the temperature gradient of these parameters were determined. The highest onset temperature (T_α = 300–325 K) was identified to be the glass transition temperature, and others (T_γ = 90–180 K and T_β = 160–205 K) were associated with the onset temperatures for limited local motions of molecules; those molecular motions were found to be affected by both the number of crosslinks and the presence of free side chains. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2875–2880, 1999     

建筑材料中甲醛含量的柱内衍生HPLC法测定

选用偏二甲肼作柱内衍生剂,利用甲醛与偏二甲肼能在适当的pH值条件下生成有较强紫外吸收的偏二甲腙的实验原理,建立了内墙涂料和胶牯剂中甲醛的柱内衍生高效液相色谱测定方法。实验讨论了甲醛与偏二甲肼反应的机理、pH值对亲核加成反应的影响,估算了流动相的pH值范围为2相似文献   

Effect of dimples on glancing shock wave turbulent boundary layer interactions

An experimental study has been conducted to examine the control effectiveness of dimples on the glancing shock wave turbulent boundary layer interaction produced by a series of hemi-cylindrically blunted fins at Mach numbers 0.8 and 1.4, and at angles of sweep 0°, 15°, 30° and 45°. Schlieren photography, oil flow, pressure sensitive paints, and pressure tappings were employed to examine the characteristics of the induced flow field. The passive control technique used a series of 2 mm diameter, 1 mm deep indents drilled across the hemi-cylindrical leading edge at angles 0°, 45° and 90°. The effects of dimples were highly dependent on their orientation relative to the leading edge apex, and the local boundary layer properties.      

紫外光固化涂料简介

本文简介感光性高分子的紫外光固化涂料的发展简史、固化机理及发展方向。     

结晶紫内酯合成工艺的研究进展

结晶紫内酯(CVL)的合成方法一般是先合成无色结晶紫内酯(LCVL),然后把LCVL氧化为CVL.本文对近年来合成LCVL和LCVL氧化为CVL的方法进行了综述.     

Effect of pigment concentration on NMR relaxometry in acrylic paints

Acrylic emulsion paint is among the most common media employed by 20th century artists. Since early acrylic paintings have begun to require the attention of conservators, scientists are working to characterize the properties of these paints to facilitate conservation efforts. In this study, we report an investigation of the physical and chemical properties of acrylic emulsion paints using single-sided NMR in conjunction with gloss measurements and scanning electron microscopy-energy dispersive spectrometry. Combining the data from these techniques gives insight into pigment-base interactions and the acrylic curing process, showing that as pigment concentration is increased in paints, the amount of acrylic base adsorbed to pigment particles increases, resulting in films with differing relaxation times. This research both emphasizes and contextualizes the utility of NMR relaxometry in studying cultural heritage objects and prompts further study into the effects of pigment concentration on the curing and conservation of paint films.     

Comparative Study of the Quantity of Volatile Organic Compounds in Water-Based Paint and Solvent-Based Applied Polyurethane

Summary: The concern about the environmental impacts generated in the production of goods and services has increased last decades. The industry has used paints and varnishes in the manufacturing process have been pressed to improve air pollution prevention. Thus, the present work aims to identify the quantitative differences of VOC's and analyze the effect of VOC's in the burning rate, in a solvent and water-based paint, applied in the manufacture of automotive steering wheels. The results has showed that the solvent-based paint contains nine times more VOC's in your formulation in relation to water-based paint, when compared liquid and volatile organic compounds present in the solvent-based paint increase the speed of combustion of the polyurethanes samples. These data indicate that a discussion on the subject must be initiated in order to reduce these emissions that can harm society.     

A physical interpretation of softening of pressure-sensitive and anisotropic materials

Several new dynamic models are proposed to explain the mechanical behaviour of softening of pressure-sensitive and anisotropic materials at a macroscopic level. If a pressure-sensitive material is loaded by a force and a variable pressure or an anisotropic material is subjected to a load with a changeable loading direction relative to the material frame, their stress–strain relationships become more complicated. Mechanical behaviours of these stress–strain relationships have to cover the feature concerning the change of pressure or loading direction, i.e. mechanical properties of pressure-sensitive material corresponding to different pressure state or anisotropic material relating to different loading direction will play an important role in deciding their stress–strain relationships. Such shift of material properties due to the variable pressure or loading history may significantly expand the traditional concept of the stability of material deformation, and the second order of plastic work being negative may be a response of stable plastic deformation, which is commonly called softening.