Sparkle measurement revisited: A closer look at the details

Four years after introduction of the first instrument for measurement of sparkle, the foundations have been reconsidered, and the pool of practical experience has been analyzed to provide a more detailed and complete picture of the subject matter. The following aspects are introduced and discussed: observation conditions and resulting requirements for imaging (sampling) and filtering, analysis of spatial periods and frequencies as a basis for filtering, spatial filtering concepts, sparkle in the frequency domain, sparkle evaluation based on analysis of single images and difference images, origins of unwanted sparkle components, scaling and offset in sparkle evaluation, and verification of the method.     

电火花技术在成型磨削加工中的应用

采用电火花加工技术和计算机控制技术 ,对成型磨削的方法进行了研究 .利用高纯石墨作磨轮电极材料 ,并将其预加工成型 ;通过计算机系统控制磨轮电极与工件间的相对运动及火花放电的参数 ,完成对工件的成型磨削加工 ;利用预成型的样板刀对磨轮进行实时修整与补偿 ,可以极大的减少电极损耗对磨削精度和表面粗糙带来的不利影响 .该技术和方法较好地解决了传统方法难以加工的高硬度、易碎和易变型等零件的成型磨削问题 .文中给出了磨轮半径损耗值的估算公式     

防眩显示屏闪耀点的研究进展

闪耀点(Sparkle)是影响防眩屏幕显示效果的重要因素之一,为满足人们对显示屏分辨率日益提高的要求,闪耀点越来越受到关注。但目前对闪耀点的确切定义,产生原因,表征手段及评价指标等尚无统一的认识和标准。本文从闪耀点现象入手,介绍了目前闪耀点主要的研究表征方法,例如Gollier和Becker各自提出了表征闪耀点的评价测试体系并给出了一系列相关参数;Evans等人在Gollier和Becker工作的基础上进行了一系列心理物理学实验来评价闪耀点现象的实际效果等等。本文就闪耀点的研究现状进行了详尽的综述,为后续屏幕闪耀点研究,建立统一的评价方法与标准提供了宝贵的参考资料。     

超声振动对电火花表面强化的作用

超声辅助电火花表面强化技术是电火花表面强化技术基础上发展起来的,将超声引入电火花表面强化可以得到质量更高的表面强化层.通过在45钢基体上添加超声振动,实现电火花表面强化过程,并据此研究超声对电火花表面强化技术的促进作用.结果表明,超声振动能够扩大电火花表面强化技术的强化层成形工艺区间,获得表面形貌更加均匀的强化层.同时...     

电除尘器用数字高频开关电源在节能减排中的应用

本文阐述了电除尘器（ESP）数字化高频开关电源的显著特点,提出了零火花率和以计算机为核心的系统多功能综合控制器等新思想,经过最佳设计后,极有助于节能减排,新的电除尘器相对使用常规工频可控硅整流电源T／R的电除尘器,可节省电能40％～90％或者可减少粉尘排放40％～90％。     

Flash A/D转换器中火花码与亚稳态现象研究

全并行模数转换器(FlashA/D转换器)结构简单,转换速度快,但电路规模较大,精度受到限制.FlashA/D转换器具有"亚稳态","火花码"等非理想特性,严重的影响了它的工作性能.本文较系统地介绍和分析了已有的一些抑制"火花码"与"亚稳态"的方法.并提出一种基于概率统计的算法,通过SIMULINK软件进行仿真,对各种编码电路对输出误码率的影响进行了研究和量化对比,结论表明wlallace Trec编码结构对"火花码"及"亚稳态"的抑制能力最强.     

Multi-angle measurement device for analysis of coating appearances

Material appearance is an important factor in product design because it tends to attract consumers. Effect coatings that contain aluminum and interference pigments are widely used in automobiles. The color and sparkle values of these coatings vary with the observation angle. Several methods have been proposed to study these variations with respect to the observation angle. However, a high angular resolution is required to understand human perception. Thus, we developed a measurement device that can analyze the color and sparkle values at a high angular resolution for multiple angles. The device captures the sample surface by using a line scan spectral camera. Because the lighting device rotates around the sample while the line scan camera is capturing images, each scan line that makes up the image contains different angle information. A comparison was performed among the results obtained from this study, a commercially available device, and a subjective value of sparkle perception. Twenty samples were required to confirm that the sparkle values calculated from this study correlated closely with the subjective scores. In addition, the difference between the color values obtained from the BYK-mac i spectrophotometer and the proposed technique was less than 3.5 (ΔE₀₀). The findings of this study will help in developing the appearance of effective coatings. In addition, using evaluation values, quality control, and improvement are possible after mass production of coatings.     

混凝土输送管失效分析及改进工艺研究

采用显微硬度计和显微镜对磨损失效的混凝土输送管进行力学性能测试及显微组织表征.结果表明:输送管连接处相对于其他位置更易受到强烈的磨粒磨损而失效.对输送管连接处进行电火花沉积WC及堆焊Co表面强化处理后.输送管连接处的表层组织细小、均匀,其耐磨性能得到较大提高.     

电火花线切割工件质量差的原因及预防措施

归纳了电火花线切割加工件产品质量差较常见的一些原因,并针对原因介绍了预防措施.     

电火花加工电源中模糊控制的应用

详细论述了利用模糊控制技术设计的单机模糊加工电流控制系统，并将 其应用于电火花数控机床的脉冲电源中。内容包括单片机模糊脉冲电源控制系统的工作原理、 模糊控制在变频脉冲电源中的实现，以及从软硬件两方面阐述了如何利用单片机实现模糊控制器。试验表明，这种控制系统 比传统的脉冲开环控制方式实时性好，精度高。