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。     

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。     

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。     

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。     

2010-2016年北京市雷电特征分析

文章介绍了闪电的观测数据和来源;利用北京2010—2016年雷电定位数据,统计分析北京市闪电活动特征,通过分析闪电的年变化、月变化和日变化的时间变化特征以及空间变化特征,得到变化规律,能够更好地做好雷电防护,为不同时期雷电特征的分析研究提供参考。     

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。     

电弧炉负荷的三相综合建模与参数辨识探讨

在电力系统工作运行中,电弧炉负荷作为一种非线性负荷,对于电网的安全、稳定以及高效的供电运行,具有非常不利的作用和影响。通过对电弧炉负荷变化对电网供电运行影响的分析,结合电弧炉负荷变化特征,建立了电弧炉负荷变化分析模型,对电弧炉负荷变化参数情况进行辨识,是研究分析电弧炉负荷变化运行特征的有效措施。     

自动气象站地温传感器改造方法

分析研究目前自动气象站地温传感器现场校准和室内检定工作中遇到的具体问题,探索地温传感器改造方法,并对改造方法的可行性进行了试验验证。试验分析发现,改造后的传感器,连续采集能力没有变化,仪器差值变化范围都≤0.1℃,55.2%的传感器最大误差值没有变化,其他有变化的传感器,变化值都≤0.1℃。     

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...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

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.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.