不确定度在链长精度测量中的应用

一个完整的测量结果应包含测量不确定度,测量不确定度的大小决定了测试结果的可信程度。对于不同产品和测试方法,影响测量不确定度的因素以及不确定度的计算方法不同。在链条行业链条产品的链长精度测量中首次引入不确定度,通过大量的试验测试和理论分析,找出了影响不确定度的主要因素。在此基础上,根据贝塞尔公式得出计算链长精度不确定度的理论公式,给出了不确定度在报告中的表述方法,讨论了不确定度对测量结果的影响。     

如何对叉车检测中方向盘自由转向量进行不确定度评定

本文用ZC-2型转向参数测试仪对叉车方向盘自由转向量的测量,得出测量结果,根据测量结果建立测量不确定度的数学模型及计算公式,并对对测量结果示值误差进行了不确定度分析得到了测量结果的不确定度。     

PTB330型气压传感器示值误差测量不确定度评定

文章通过建立模型,分析了PTB330型气压传感器测量结果的不确定度来源、评定测量结果的不确定度分量,得出了示值误差测量的合成标准不确定度及扩展不确定度。文章选取10台气压传感器按照自动气象站气压传感器检定规程要求,对各检定点进行测量结果不确定度评定,为同类型的气压传感器测量的检定结果提供科学的参考依据。     

机械产品测量不确定度评定

对测量误差和测量不确定度的基本概念作了简单介绍,并举例说明了测量不确定度A类和B类评定以及测量结果不确定度评定,为机械产品测量不确定度评定提供参考.     

坐标测量机测量端面距离的不确定度评定

以坐标测量机端面距离测量为例,全面分析测量全过程中影响测量结果不确定度的主要因素,建立坐标测量机测量端面距离的不确定度数学模型;利用蒙特卡罗数值模拟方法进行仿真,得到被测参数的测量不确定度,给出了完整的测量结果,提升了坐标测量机的应用价值。将蒙特卡罗模拟方法评定结果与测量不确定度表示指南给出方法评定的结果进行比较,可以看出应用蒙特卡罗模拟方法对于评定复杂模型测量不确定度更方便、高效。     

试验机测量不确定度的研讨

微机液压万能材料试验机在材料试验中应用十分广泛.本文根据测量不确定度的原理和方法对试验机的负荷示值测量结果的不确定度来源进行了详细分析,并对测量结果的不确定度也进行了仔细的评定,以此作为材料试验机测量不确定度评定的一个典型实例.     

试验机测量不确定度的研讨

微机液压万能材料试验机在材料试验中应用十分广泛。本文根据测量不确定度的原理和方法对试验机的负荷示值测量结果的不确定度来源进行了详细分析,并对测量结果的不确定度也进行了仔细的评定,以此作为材料试验机测量不确定度评定的一个典型实例。     

播种机排种量测量结果不确定度评定和分析

依据DG/T 007-2019《播种机》、GB/T 9478-2005《谷物条播机试验方法》与GB/T 27418-2017《测量不确定度评定和表示》对播种机排种量测量结果的不确定度进行评定,推导出适用于播种机排种量测量结果不确定度评定公式,分析了影响测量结果不确定度的因素,提出了适用于播种机排量测量结果不确定度分析的方法。     

车载充电机输出电流误差试验测量不确定度评定

考虑CNAS对测量不确定度的重视,以及测量不确定度对测量、试验结果的影响,结合电动汽车非车载充电机输出电流误差试验,采用分析测量过程、建立测量模型、确定合成标准不确定度表达式、评定不确定度分量、计算合成标准不确定度数值、评定扩展不确定度和报告测量结果的七步骤法评定测量不确定度,使测量不确定度评定简便易懂,有助于检测实验室实施CNAS-CL01:2018《检测和校准实验室能力认可准则》有关"测量不确定度评定"的要求。     

原子荧光法测定奶粉中砷含量不确定度评定

用测量不确定度表示检测结果是当前国际上约定做法,然而如何对测量结果的不确定度进行合理评定,一直是困扰检测实验室的一个难题。作者依据测量不确定度的评定原则,通过实例,简要地阐述了原子荧光法测定奶粉中砷的不确定度评定方法,对检测领域测量不确定度的评定具有借鉴意义。     

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.     

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.     

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....     

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.