自由空间反射法检测飞灰含碳量的实验研究

为了提高微波法检测飞灰低含碳量的灵敏度,提出了一种静态条件下检测飞灰低含碳量样品的新方法,测试频段为9.84～15 GHz。详细说明了测试的基本原理及方法,利用时域门等技术,结合5个电厂灰样含碳量为0%～20%范围内的测试结果进行分析,分别得出飞灰含碳量与幅值衰减、线性幅值之间存在的规律。经线性拟合后,在9.84～11 GHz频段时,除某厂灰样具有特殊性外,其余4个厂拟合度大于0.97。另外,在高含碳量时采用不同处理方式得到完整的测试结果。测试结果表明,与自由空间传输法相比,反射法可以解决低含碳量测试灵敏度低的问题。     

自由空间反射法检测飞灰含碳量的实验研究EI北大核心CSCD

为了提高微波法检测飞灰低含碳量的灵敏度,提出了一种静态条件下检测飞灰低含碳量样品的新方法,测试频段为9.84-15 GHz。详细说明了测试的基本原理及方法,利用时域门等技术,结合5个电厂灰样含碳量为0%-20%范围内的测试结果进行分析,分别得出飞灰含碳量与幅值衰减、线性幅值之间存在的规律。经线性拟合后,在9.84-11 GHz频段时,除某厂灰样具有特殊性外,其余4个厂拟合度大于0.97。另外,在高含碳量时采用不同处理方式得到完整的测试结果。测试结果表明,与自由空间传输法相比,反射法可以解决低含碳量测试灵敏度低的问题。     

基于特征选择的飞灰含碳量影响因素分析

本文分别提出了基于互信息变量选取、相关系数法、方差选择法等特征选择方法对影响飞灰含碳量的因素进行选择,并通过PLC和上位机组合的方式对选择得到的特征量进行实现和在线监控。首先,介绍了锅炉燃烧机理,机理分析得到影响飞灰含碳量软测量模型建立的辅助变量;然后,针对选取得到的辅助变量进行数据预处理,以处理之后的数据作为特征选择的原始数据;最后,对处理后的数据采用互信息法、相关系数法、方差选择法等方法对影响飞灰含碳量的因素进行特征选择,并通过上位机组态软件WinCC对飞灰含碳量的影响因素进行在线监控。结果表明:本文通过特征提取得到的特征量建立的动态模型相较于传统的飞灰含碳量模型具有更高的实用性和准确性,有着良好的预测精度与较高的预测速度,能够用于现场飞灰含碳量测量。     

基于PSO-BP神经网络的飞灰含碳量测量方法

针对飞灰含碳量测量困难的问题,提出了基于粒子群算法优化BP神经网络的飞灰含碳量测量方法。以飞灰含碳量影响因素为模型的输入,飞灰含碳量为模型的输出,建立飞灰含碳量预测模型,并将预测结果和传统BP神经网络预测结果相比较。实验结果表明,该测量方法具有较高的预测精度。     

X射线衍射法测试TC_4钛合金喷丸残余应力的精确度研究

从残余应力测试原理出发,结合自制原位拉压试验装置,评估了X射线衍射法测试钛合金喷丸表面残余应力的准确度。同时,利用卷积和概率论推导测试不确定度的计算方法,并对X射线衍射法测试钛合金喷丸表面残余应力的不确定度进行分析。结果表明,X射线弹性常数1/2S_2~(hkl)是影响残余应力测试准确度的关键参数,随着喷丸样品表面状态的变化,残余应力测试不确定度发生不同程度的波动。     

基于信息融合技术的锅炉飞灰含碳量测控系统

降低飞灰含碳量对火力发电厂提高锅炉燃烧经济性具有重要意义,而飞灰含碳量难以在线测量.目前广泛采用微波飞灰测碳仪进行在线监测,但在实际中烟气密度和流速对仪器的测量精度有重要影响,使测量结果产生较大波动.设计了对烟气密度和流速的测量方法,并构造了基于多传感器信息融合技术的测量系统,利用BP神经网络对互补的信息进行有效融合,该方法在一定程度上提高了飞灰含碳量的测量精度,进而给出一种模糊自寻优的方法控制飞灰含碳量.     

基于KPCA和LSSVM的锅炉飞灰含碳量软测量

在火力发电厂中,飞灰含碳量是燃烧经济性的主要指标。飞灰含碳量精准的实时测量有益于控制空气与燃煤比例,提高锅炉的燃烧效率,提升经济性并且减少污染和资源浪费。为提高锅炉燃烧经济性,降低发电成本、降低煤耗、节约能源,需要合理控制飞灰含碳量。本文提出了一种基于KPCA和LSSVM的软测量模型来解决飞灰含碳量的精确测量和滞后问题。首先要选取样本,对数据进行采集,然后对于选取的与飞灰含碳量相关的辅助变量进行特征提取,以此作为最小二乘支持向量机软测量模型的输入,提升了软测量模型的精度。本文提出的方法为飞灰含碳量的及时、精确测量提供了理论上的依据。     

JKZ型电子探空仪基测箱校准结果的不确定度评定方法

文章基于JKZ型电子探空仪基测箱多参数的特点和目前的校准方法,依据JJF 1059.1—2012《测量不确定度评定与表示》的要求,首先介绍了采用GUM法评定不确定度的一般流程和数学模型的建立,其次结合实际校准工作,通过实例分别对温度、湿度、气压、电压4种参数的校准结果进行了不确定度分析和评定。结果表明：JKZ型基测箱的不确定度评定需分别给出4种测量参数的不确定度,且电压校准结果的不确定度即为基测箱电压分辨力引入的不确定度,而在文章测量条件下由分辨力引入的不确定度均大于示值重复性引入的不确定度,因此在评定其他3种测量参数时可忽略基测箱示值重复性引入的不确定度,直接采用其分辨力引入的不确定度进行评定。     

大跨距轴承座同轴度测量及安装方法

介绍了大跨距轴承座同轴度测量及安装方法。详细阐述了所需设备、测量原理和具体操作步骤。采用该方法很好地解决了高精度、大跨距轴承座同轴度的测量及安装。该方法操作简便,尤其适用于轴承座直径较大且轴承座间距较大(大于2500mm)的轴孔同轴度测量及安装。     

国产690TT合金传热管导热系数的测定及其不确定度评定

导热系数是蒸汽发生器及传热管设计分析中的重要参数。应用激光闪射法对国产690TT合金的热扩散系数、比热容进行了测试,根据测试结果,得到导热系数,并对导热系数测试结果进行了不确定度评定,包括测量热扩散系数和比热容引入的不确定度分量的评定、由数值修约引入的不确定度分量的评定,以及合成不确定度和扩展不确定度的评定,最终得到不确定度评定报告。测试结果表明,100～350℃范围内,国产690TT合金传热管导热系数比ASME规范给出的N06690对应温度导热系数低约3%～10%,导热系数随温度变化满足线性关系λ=0.014T+11.54。     

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.