共查询到20条相似文献,搜索用时 78 毫秒
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一种新的图像清晰度评价方法 总被引:3,自引:0,他引:3
针对图像评价中较为重要的清晰度问题。运用了一种基于焦点窗口模式的能量梯度评价函数的方法。该函数较其它的函数具有较好的计算效率,比起一般的评价方法具有更高的信噪比、可靠性和清晰灵敏度,更好地满足了对图像清晰度评价的要求。 相似文献
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高效缠绕管式换热器的节能分析与工业应用 总被引:3,自引:1,他引:2
介绍了缠绕管式换热器的节能原理,利用工业应用实例对缠绕管式换热器的节能进行了分析,并根据工业实际情况,提出了采用缠绕管式换热器,可使工艺流程简洁、操作条件优化、大幅度降低能耗的观点。 相似文献
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讨论了随机参数服从正态分布变量相关情况下螺旋管簧的可靠性优化设计问题,在基本随机参数均值、方差和相关系数已知的情况下,应用变量相关情况下可靠度指标计算的优化方法并通过计算机程序给与实现,迅速准确地得到了螺旋管簧的可靠性优化设计信息.计算结果表明,提出的方法是一种有效、实用的方法. 相似文献
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分析了螺旋输送机螺旋管常用连接形式的优缺点,运用弹性力学的理论,对近年出现的滑块式连接进行等强度和等刚度的计算,从而合理确定了截面尺寸。根据挤压强度验算了轴的承载能力,证明这种连接能满足工程上的强度要求。 相似文献
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提出了一种新的约束优化方法,此方法根据设计点附近“定向单元”的函数值信息确定出有效的搜索方向。进而较快地获得最优点。本方法的算法原理简单,易于编程,经三个例题验证,取得了满意的结果,说明了该方法的正确性和可靠性。为优化设计领域提供了一种新的约束优化算法。 相似文献
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一种新的敏捷虚拟企业合作伙伴选择与评价方法 总被引:10,自引:2,他引:10
针对敏捷虚拟企业合作伙伴选择和评价中出现的待选企业多、信息模糊性增加等新问题,以及传统层次分析法和其他模糊层次分析法在处理类似多方案问题中出现的判断矩阵不一致性等缺陷,将层次分析法、三角模糊数理论和其他基本模糊理论相结合,提出了一种合作伙伴选择和评价的新方法。该方法采用基于三角模糊数的层次分析法求取各层次指标的权重,采用模糊关系矩阵确定各待选企业的属性值,最后归并获得评价结果。在Matlab环境开发了基于该方法的具体应用系统,并进行了实例分析计算。 相似文献
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石油化工企业具有易燃、易爆的特点,火灾、爆炸危险性大。为减少火灾事故,介绍了“工厂火灾、爆炸场所危险度综合评价法”,“道氏法”是该法的基础。分析了“道氏法”的不足,而提出了固定危险和现实补偿的综合性计算方法,并对石化企业的制氢装置进行了评价。实例证明该法能用于评价石化企业危险设备、装置与场所的火灾、爆炸危险程度,它具有使用方便、效果明显的优点。 相似文献
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超临界流体在螺旋管内的传热技术在化工领域被广泛应用。由于其传热与流动机理的复杂性,使得目前这方面的研究相较于直管内的还很匮乏。综述了近几年来国内外学者关于超临界流体在螺旋管内对流换热的研究进展,包括以CO_2和H_2O等常见工质为主的数值模拟研究与试验研究。对数值模型及传热机理进行了分析比较,提出该研究的未来发展方向;总结了现有研究中的浮升力影响准则,并分析了质量流量、压力、热流量以及螺旋管结构参数对传热特性的影响机理。此外,对目前螺旋管内超临界流体的换热关联式进行了归纳总结。期望能对超临界流体在螺旋管内的特殊换热机理有更深入的理解,为今后的具体研究工作奠定理论基础。 相似文献
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针对典型新型绕管式多相流冷却器管板及封头组件在使用工况条件下,采用极限载荷与有限元结构应力应变分析计算方法,对其结构应力应变进行分析计算,并依据JB 4732等压力容器设计制造标准规范,对其结构设计安全性和合理性进行评价,为企业完善设计规范、提高产品的设计质量和设计效率、降低设计生产制造成本打下了良好基础。 相似文献
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Tstomu Moroi Takashi Kuboki Makoto Murata 《Journal of Mechanical Science and Technology》2007,21(10):1548-1552
Wall thickness is constant in the axial direction when aluminum tubes are formed by conventional extrusion process. Tubes
with internal ribs have high strength in comparison with those without ribs. These tubes can be used, for example, as structural
parts, heat sinks, and impact absorbers. The existence of some holes at ribs enhances the function and value of the tubes.
The appropriate positioning of holes at ribs reduces the weight of structural parts without strength reduction. In the case
of heat sinks, holes change the fluid flow and would realize effective heat transfer. In this research, a new extrusion method
is proposed by authors for manufacturing tubes with holed ribs. A new extrusion method is applied by FEM analysis. Model experiment
was carried out based on the results. The method involves the use of a unique mandrel that has a slit along its axis and two
guides at the slit exit. A holed sheet is fed through the slit and joined to the inner surface of the tube. In particular,
the effect of the guide height is clarified in this study. 相似文献
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Jui-Jen Chuang Daniel C. H. Yang 《The International Journal of Advanced Manufacturing Technology》2007,34(7-8):714-723
In this paper, a method for generating boundary-conformed pocketing toolpaths is developed. Based on the 2D Laplace parameterization
of pocket contours and the redistribution of the original Laplace isoparametrics, continuous toolpaths are generated. These
generated toolpaths have neither thin walls nor leftover tool marks. Detailed algorithms are formulated in steps. The method
can be applied to general pockets either with or without islands. Some examples are provided to demonstrate the applicability
of this method. In most cases, the method can successfully generate satisfactory toolpaths for arbitrary shaped pockets. However,
according to the shape of the pockets and the distribution of the islands, when using this method, over machining may occur
in some narrow or bottlenecked areas. Further investigation on how to alleviate this problem is needed. We believe that this
method provides an alternative choice for pocket machining. 相似文献
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Dr Eung-Suk Lee Suk-Hwan Suh Jin-Wook Shon 《The International Journal of Advanced Manufacturing Technology》1998,14(1):43-49
A comprehensive method for measuring the systematic errors of CNC-machine tools has been studied. The method used for measurement and calibration of machine tool errors should be general and efficient. The objectives of this study include:
Using the same method, the machine tool status can be completely identified and its accuracy can be enhanced by software error compensation. The point compensation method can be used as a means for modifying the nominal tool path and on-the-machine inspection where the machine tool is used as a coordinate measuring machine. The validity of the error calibration method proposed in this paper was shown using a vertical 3-axis CNC machine with a laser interferometer and a ball bar technique. 相似文献
1. | Volumetric error modelling. |
2. | Experimental procedure for error measurement. |
3. | A tool position and path compensation method. |
4. | The verification method. |