热湿独立控制的复合空调系统能耗分析

通过对热湿独立控制复合空调系统能耗分析中所采用的新风量的异同分析,认为对两种新风量的选择包含了对设备的两种理解,一种是设备固定,也即再生温度一定;另一种是除湿量固定,再生温度可调,除湿风量为新风量和部分回风量的混合.通过实例论证了两种比较方式能耗的差异.设备固定方式中所需的再生温度和再生热量要远高于除湿量固定方式,总能耗也要高于后一种.     

美法核级电气设备鉴定标准比较

对比分析了美国标准和法国标准,特别是美国的IEEE 323、344和法国RCC-E标准对核级电气设备的鉴定要求的异同,得出了两种标准并无本质上的差异,在实际应用中可互相参考的结论,给按两种标准鉴定的设备互通互用打下了基础,对于扩大设备采购范围、降低采购成本有很重要的参考意义。     

曲形零件的螺纹加工对照

通过对比曲形零件螺纹的两种加工方案,比较了常规加工与数控技术加工在加工工艺及效率、质量、成本等方面的差异,企业可以根据零件批量大小及设备条件灵活、选择。     

判断设备故障的动态分析法

一、概述 在设备故障诊断中,正在逐步发展以设备实际技术状态为基础的视情修理制。实行视情修理制的关键技术之一是对设备的诊断参数的数据进行适当的处理,制订判断设备是否有故障的判断方法。目前,国内外普遍使用的判断方法有两种:一种是标准值方法,即把诊断参数实测值与标准值比较,以实测值是否大于标准值来判断设备技术状态是否正常;另外一种是动态分析法,即把实测值与该设备正常运行时的数据进行比较,用数理统计方法判断实测值是否发生显著差异来判断设备是否出现故障。 上述两种方法各有利弊。前者因其使用方便而受现场工作者欢迎,国外多采用这种方法。但在使用该法时必须满足下列条件:1)同类设备的质量水平一致;2)     

EDDL和FDT技术的研究及实现

为了给现场总线设备的描述提供一个规范统一的方法,促进了现场总线设备描述技术的研究和发展。电子设备描述语言(EDDL)和现场设备工具/设备类型管理器(FDT/DTM)是目前较为流行的两种描述技术。本文对这两种设备描述技术进行了具体的技术分析和比较,并且给出了这两种技术在Profibus PA设备上的实现。     

焊缝的随机振动多轴频域疲劳方法研究

基于制造行业对焊接结构随机振动疲劳评估的迫切需要,以铁道车辆转向架悬挂设备天线梁为分析对象,研究不同频域方法的焊缝疲劳损伤结果差异。介绍了焊缝随机振动多轴疲劳的频域方法——临界面法(CPM)和频域结构应力法(FSSM)的原理,依据IEC 61373与BS 7608标准,应用两种方法预测了焊缝的疲劳损伤,对比分析了两种方法的损伤值差异。研究结果表明：CPM与FSSM相比,前者得到的损伤值较大。     

设备故障的模糊诊断及其软件研制

由于设备故障具有模糊性，因而模糊数学方法在设备故障的诊断中显示出其优越性。该文介绍了两种常用的基于模糊数学思想的诊断方法，并将这两种方法用软件形式实现，制成了设备故障模糊诊断系统。     

现代企业设备资产管理信息化系统的研究与实践(三)

2.基础资料数据库基础资料数据库是设备资产管理信息化建设的重要基础内容,是系统专家支持的重要部分,是保持系统高质量运行的神经和中枢。设备资产管理信息化系统标准体系的基础资料数据库可概括为"五个两",即:①两种资料。设备基本资料、设备规格资料。②两种规范。设备类别点检规范、设备类别维修规范。③两种基准。设备点检基准、     

水泥混凝土搅拌站称量控制系统研究

水泥混凝土搅拌站是生产水泥混凝土的主要设备,该设备的称量精度是需要严格控制的指标,该指标直接影响着生产混凝土的质量。不同品牌的搅拌站所配置的称量系统不同,性能也各有差异。针对落差值计量法与抖动称量法进行了深入研究,发现了该两种计量方法各自都存在一定的问题,提出了在抖动称量法的基础上的自适应计量法。     

压缩型设备线夹(SY系列)标准中的几个问题

文中通过探讨压缩型设备线夹(SY系列)两种工艺利弊及主要结构尺寸的差异,从中找到最佳的方法,将GB/T2314-1998标准中有关压缩型(SY系列)设备线夹的主要尺寸作适当调整,以便更好地为生产服务。     

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.     

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。     

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....     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.