基于变化减少方案的变化性及其应用研究

在变化减少方案（VRP）理论的基础上,研究了变化性的层次模型：参数层、实体层和体系层,并从产品结构变化性和制造结构变化性两个方面分别分析了变化性的内容、形式及其使能技术。提出了产品结构变化性和制造结构变化性集成化的思想,以及实施变化性的策略和方法。针对参数层变化性,提出了一种支持产品结构变化性和制造结构变化性的零件族模型,并通过一个实例进行了验证,结果表明,基于VRP的产品变化性在提供多样化产品的同时,可以有效控制产品成本、缩短产品交货期。     

主动思变 致胜有道——《创新·转型·绩效:企业蜕变的新思维》

政治经济形势在变化、企业界限在变化、市场在变化、客户在变化、行业在变化、区域发展在变化……作为现代经济基本单位和市场主体的企业,所处的经营环境正变得日益复杂。     

春雨纷飞展生机 成形行业精英齐聚2014CCMT

正正应中国机床工具工业协会常务副理事长兼秘书长陈惠仁的一句话:"变化催生希望,变化倒逼转型,变化孕育机会,变化创造未来",因此萌生了此次CCMT2014展会主题"新变化·新未来"。带着这样寻变化的心态,本刊记者在展会现场走访了成形行业的参展精英。     

PC-7系列挖掘机液压与电控系统（四）

8.PC-EPC电磁阀 PC—EPC电磁阀主要作用是感知发动机实际转速,给予相应信号以调节泵流量。由于工况变化,发动机转速也会变化,此时与发动机匹配的泵流量也应相应变化。发动机转速变化通过安装于发动机飞轮壳的转速传感器传给机载计算 机,然后计算机发出泵流量变化的指令,PC—EPC电磁阀接收此指令,通过Pc阀适当调节泵流量,以对应发动机转速的变化。     

拦焦车吊辊受热变形适用公差的研究

通过研究温度变化对零件尺寸的影响,计算温度变化时,轴承和吊辊的尺寸变化量,由此来确定一组温度变化时,轴承与吊辊相配合,更为合理的配合公差。     

基于GCr15轴承钢淬回火组织的时效尺寸变化预测模型

轴承钢在服役过程中的尺寸变化及尺寸稳定性对轴承的精度保持性和服役性能有着重要影响。针对轴承钢尺寸变化行为的预测问题,提出基于高碳铬轴承钢亚稳组织转变的时效尺寸变化预测模型。对比时效尺寸变化的预测值与测量值,预测值的相对误差不超过5%,两者吻合良好。然后,基于时效尺寸变化预测模型分析淬火和回火工艺对时效阶段尺寸变化的影响规律。分析结果显示,淬火工艺决定了时效尺寸变化程度的上下限,且上限随淬火加热温度提高而增加。回火工艺决定其起点,且提高回火温度可以显著降低时效尺寸变化程度。分析结果还显示,淬火态GCr15轴承钢在180℃等温回火2 h即可获得较高的尺寸稳定性。该时效尺寸变化预测模型可为预测GCr15轴承时效尺寸变化程度及优化和控制淬回火工艺提供依据。     

石家庄地温的垂直变化特征

本文利用石家庄地区5个观测站2008～2010年逐日地面温度、草面温度和浅层地温观测数据,分析讨论了该地区地温的垂直变化特征给出了其年变化、日变化和定时变化以及振幅和波动变化的结果,并解析了其原因,可为华北地区农业生产的影响因子研究提供参考。     

可调叠加式进口压力补偿器

在液压控制技术领域,许多变化的负载会导致执行元件运动速度的变化,为了解决这个问题000887,设计研制了可调叠加式进口压力补偿器,并通过试验液压系统模拟变化负载的工况,进行数据采集和试验分析。试验结果表明:该进口压力补偿器性能稳定可靠,完全可以解决变化负载带来的执行机构速度变化的问题。     

基于GRNN神经网络的中厚板轧机宽展预测模型

为了实现中厚板轧机在轧制过程中的宽展变化自动预测和控制,分析了轧制过程中宽展变化的影响因素,在神经网络技术和现场实测数据的基础上,利用Matlab人工神经网络工具葙,应用GRNN广义回归神经网络建立宽展变化预测模型,来提高轧制宽展变化预测的精度.结果表明,该方法建立的模型可以实现对宽展变化的预测,预测精度有较大提高.     

API 526-2009与API 526-2002对比分析

分析了API 526-2009与API 526-2002之间的主要变化内容,对主要的变化内容进行了归纳,分析了变化原因。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.