共查询到18条相似文献,搜索用时 296 毫秒
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电子束曝光机是研制大规模集成电路的重要设备。它的运行必须由计算机进行控制并提供数据。本文简要地介绍了之类曝光机所需的控制软件及数据处理软件的构成及功能,并介绍了软件开发中的一些考虑。 相似文献
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PCB曝光机照明系统的均匀性仿真与研究 总被引:2,自引:2,他引:0
近年来,电子信息类产品在不断地追求着高性能化,印刷电路板也随之高密度、微线化。紫外线曝光机是印制板制造工艺中的重要设备,而光学曝光作为PCB制作工艺过程中的一个重要环节对光照度的均匀性要求比较严格,现应用非成像光学的设计方法,实现了一种新型的曝光机均匀照明系统,并使用基于蒙特卡罗法的光线追迹软件对该光学系统进行了模拟仿真。实验表明,采用该研究设计的照明系统能够改善PCB曝光机紫外照明光源的配光性能,光强分布均匀稳定、能够满足光学曝光过程对光源的指标要求,具有可操作性。 相似文献
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航源公司近期开发出PCB生产设备由中国航天工业总公司所属航源机电设备有限公司(以下简称航源)与国营200厂联合生产的EXPO’型大功率R面曝光机于今年初正式推出。该曝光机是全部引进意大利CEDAL公司同类机型的图纸和关键部件,按航天工业质量保证体系要... 相似文献
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《Measurement》2016
The boundary approach for the assessment of daily exposure to electromagnetic fields (EMF) has been recently proposed for the continuous and broadband EMF monitoring of the Serbian Electromagnetic Field Monitoring Network – SEMONT. This approach is based on the determination of the daily upper and lower exposure boundaries, combining data of the continuous in situ EMF monitoring in a broadband frequency range and the minimal and maximal prescribed reference levels. The real exposure is positioned between these boundaries. In this paper, the enhancement of the boundary approach is presented. By adjusting the existing boundaries and reducing the difference between them, the precision of the daily exposure assessment in the SEMONT system has been improved. The frequency selective measurement has been used to determine the frequencies on which EMF sources radiate over a particular area and in situ location. Consequently, the new minimal and maximal reference levels can be selected; these are suitable for a particular in situ location and should be used for the calculation of exposure boundaries on that location. A simple in situ test measurement of the high-frequency electric field strength was performed, in order to verify the proposed adaptive boundary approach. The analysis shows that this approach attained reduction in boundaries difference of 36.25%, regarding the Serbian legislation, resulting with the increased precision of the daily exposure assessment for the broadband EMF monitoring. 相似文献
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一种帘幕式快门曝光精度分析 总被引:1,自引:0,他引:1
为了确定帘幕式快门各尺寸参数曝光精度的关系,推出曝光精度的数学模型。分析了影响快门曝光时间精度的主要因素,用误差合成法对快门曝光时间进行了精度分析,为设计提供了依据。首先,结合帘幕式快门的工作原理及快门的曝光时间表达式建立了曝光精度的数学模型。然后,对曝光时间表达式中的各个参数的误差进行了分析,应用误差合成法对各个参数误差对曝光时间的影响程度做了分析计算。最后,对现有航空相机中应用的快门进行了精度的分析计算。实验表明:曝光时间精度随着帘缝宽度的增加而提高,现有航空相机的快门的曝光时间最低精度为曝光时间的6.4%,高于理论计算精度8.59%。在1/1000s-1/100s范围内快门的有效曝光时间与帘缝宽度成正比,帘缝宽度对曝光精度的影响是帘缝速度对曝光精度影响的3.6倍,快门曝光时间的精度随着帘缝宽度的增加而提高。 相似文献
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《Mechanical Systems and Signal Processing》2007,21(6):2560-2574
Recently, the issue of machine condition monitoring and fault diagnosis as a part of maintenance system became global due to the potential advantages to be gained from reduced maintenance costs, improved productivity and increased machine availability. This paper presents a survey of machine condition monitoring and fault diagnosis using support vector machine (SVM). It attempts to summarize and review the recent research and developments of SVM in machine condition monitoring and diagnosis. Numerous methods have been developed based on intelligent systems such as artificial neural network, fuzzy expert system, condition-based reasoning, random forest, etc. However, the use of SVM for machine condition monitoring and fault diagnosis is still rare. SVM has excellent performance in generalization so it can produce high accuracy in classification for machine condition monitoring and diagnosis. Until 2006, the use of SVM in machine condition monitoring and fault diagnosis is tending to develop towards expertise orientation and problem-oriented domain. Finally, the ability to continually change and obtain a novel idea for machine condition monitoring and fault diagnosis using SVM will be future works. 相似文献
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设备噪声监测中主分量的特征表示 总被引:3,自引:2,他引:1
研究了设备噪声监测中主分量特征表示的提取及应用。在设备噪声时域和频域统计模式特征基础上,通过主分量分析探讨了设备噪声模式的主分量特征表示方法,引入相关度的概念分析了主分量特征表示对设备状态的表征能力,提出了选择有效维数的主分量特征表示进行设备噪声监测的方案。通过在EQ6100 型发动机上预先模拟四种连杆轴承磨损故障,测取噪声信号,实例分析显示了低维主分量特征表示可以有效表征设备状态。实验最后对测试集样本进行状态监测得到了100%的准确率,表明了主分量特征表示用于设备噪声监测的有效性。 相似文献
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Thermal error monitoring technology is the key technological support to solve the thermal error problem of heavy-duty CNC(computer numerical control) machine tools. Currently, there are many review literatures introducing the thermal error research of CNC machine tools,but those mainly focus on the thermal issues in small and medium-sized CNC machine tools and seldom introduce thermal error monitoring technologies. This paper gives an overview of the research on the thermal error of CNC machine tools and emphasizes the study of thermal error of the heavy-duty CNC machine tool in three areas. These areas are the causes of thermal error of heavy-duty CNC machine tool and the issues with the temperature monitoring technology and thermal deformation monitoring technology. A new optical measurement technology called the ‘‘fiber Bragg grating(FBG) distributed sensing technology' for heavy-duty CNC machine tools is introduced in detail. This technology forms an intelligent sensing and monitoring system for heavy-duty CNC machine tools.This paper fills in the blank of this kind of review articlesto guide the development of this industry field and opens up new areas of research on the heavy-duty CNC machine tool thermal error. 相似文献
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S. Saravanan G.S. Yadava P.V. Rao 《The International Journal of Advanced Manufacturing Technology》2006,28(9):993-1005
In modern industry, machinery must become increasingly flexible and automatic. In order to increase productivity, enhance
quality and reduce cost, machine tools have to work free of any failure. When a failure occurs in a machine tool, it is necessary
to identify the causes as early as possible. Machine tool condition monitoring is very important to achieve this goal. Condition
monitoring is generally used on the critical subsystem of any machine tool. This paper endeavors to focus on the condition
monitoring aspects on the machine tool element. In the present study, a critical subsystem has been identified based on the
failure data analysis. Condition monitoring techniques like vibration monitoring, acoustic emission, Shock Pulse Method (SPM)
and surface roughness have been successfully used for fault identification. 相似文献