基于第二制冷剂量热器法的压缩机制冷量测量不确定度分析

介绍使用第二制冷剂量热器法测量压缩机制冷量的基本原理,以名义制冷量为13.5k W的某样机为例,开展测量不确定度评定分析,结果表明:试验的A类测量不确定度为0.00435k W,B类测量不确定度为0.14780k W,扩展不确定度的相对值为2.2%;在此基础上,分析影响测量不确定度评定结果的主要因素,指出提高量热器出口制冷剂比焓hg2、膨胀前实测制冷剂液体比焓hf2和规定工况下压缩机吸气比焓hg1等3个关键参数的测量精度可以显著改善测量结果的不确定度。     

中国计量院成功研制出材料逆反射系数测量仪器

中国计量科学研究院光学所历经4年,终于完成了“逆反射系数测量装置的建立与研究”。该项目研制的逆反射系数测量装置,成功实现了我国材料逆反射系数的高准确度测量和校准,测量结果不确定度达3．6％（k=2）;该装置采用光强标准灯组对测量系统进行量值溯源,     

单元式空调机制冷量不确定度的研究

详细介绍了单元式空调机标准GB/T 17758-2010空气焓差法测量制冷量的数学模型及计算公式,编制了相应的计算软件。同时对额定制冷量为10k W单元式空调机的试验数据进行了分析计算,并对测量结果的不确定度进行了评定。提出了减小制冷量测量不确定度的途径,用以提高实验室测量数据的准确性和可信度。     

ICP-MS灵敏度及检出限测量不确定度评定

电感耦合等离子体质谱仪（Inductively Coupled Plasma Mass Spectrometer）校准过程中的不确定度评估是量值溯源过程的重要组成部分。本文依据JJF 1059.1-2012《测量不确定度评定与表示》和JJF 1159-006《四级杆电感耦合等离子体质谱仪校准规范》等技术规范,建立ICP-MS灵敏度及检出限测量结果的不确定度评定数学模型,系统分析测量不确定度来源,对测量结果进行不确定度评定。结果表明：ICP-MS灵敏度的相对扩展不确定度为6.1%, k=2,测量结果的不确定度主要来源于标准物质引入的不确定度;ICP-MS检出限的相对扩展不确定度为47%,k=2,测量结果的不确定度主要来源于灵敏度引入的不确定度。本文为系统评估ICP-MS的灵敏度及检出限的不确定度和开展该项目的校准、研制ICP-MS校准用标准物质提供参考。     

电容薄膜真空规校准方法的研究

本文利用电容薄膜真空计校准装置、高精度数字压力计、稳压电源和数字多用表，采用比较法完成了对（1～1000）Torr绝压电容薄膜真空规的量值溯源，扩展不确定度为U=(0.69%～0.02%)(k=2)。     

基于GUM法的压缩机性能测试不确定度分析

因在压缩机性能测试过程中直接测量得到的各项参数及其不确定度均会对最终结果产生不同程度的影响,为了找到影响结果的主要因素并合理改善这种情况,本文依据GB/T 5773-2016对某涡旋式压缩机进行了性能测试,并基于GUM法对测量结果进行了不确定度分析和敏感度分析。结果表明：压缩机的制冷量测试结果为108.26 kW,合成标准不确定度为0.58 k W,扩展不确定度的相对值为1.07%;对测量结果不确定度产生最大影响的因素是温度仪器的精度,精度提高1倍,可使测量结果的不确定度降低21.15%。     

风云卫星的红外遥感亮度温度国家计量标准装置

综述了国际上美国、德国、俄罗斯的典型红外遥感亮度温度标准装置的研究现状,着重介绍了由中国计量科学研究院研制的用于风云卫星红外载荷黑体定标的红外遥感亮度温度国家计量标准装置(VRTSF)。给出了VRTSF的设计方案,描述了它的结构和光路。设计了满足风云卫星红外载荷定标黑体工作环境的真空低背景实验舱,建立了满足量值溯源需求的标准黑体辐射源作为量值标准器。标准变温黑体辐射源的温度覆盖190K~340K,口径为30mm,空腔发射率为0.999 9,温度不确定度优于50mK@300K/10μm(k=2)。该装置的光谱为(1-1 000)μm,光谱分辨率为0.2cm-1,可满足多种红外载荷的定标需求。该装置具有高温度不确定度水平、高光谱分辨率和扩展性强等特点,如未来该装置温度覆盖至(100-500)K,将会满足大部分红外载荷量值的溯源需求。     

时间戳服务到 UTC(NIM)的溯源方法研究

原子时标国家计量基准 UTC(NIM)由中国计量科学研究院维护和保持,溯源至协调世界时(UTC),是统一全国时间频 率量值的最高依据。 随着信息技术的不断发展,时间戳服务被广泛应用于司法、医疗、金融、电子商务、知识产权等领域。 根据 我国在贸易结算、医疗等领域对法制计量的需求,时间戳机构(TSA)提供的时间应溯源至 UTC(NIM)以实现国内统一和国际互 认。 本文提出使用一种校准器对 TSA 提供的时间进行远程和本地评估。 实验结果表明,在局域网进行本地校准时,TSA 与 UTC (NIM)时间偏差的不确定度(k = 2)小于 2 ms;在广域网环境下,即使校准器与 TSA 之间相距超过 1 000 km,TSA 与 UTC(NIM) 时间偏差的不确定度(k = 2)小于 713 ms。     

超短基线水声定位仪量值溯源方法研究

超短基线水声定位仪不仅广泛应用于水运工程、港口航道保障及海洋工程调查等领域,在水下救险、海上救援搜寻、沉船打捞等方面也展现出得天独厚的优势。为了准确评价超短基线定位仪的测量性能,基于研发的多维运行控制机构,该文提出了超短基线水声定位仪斜距测量准确度的计量校准方法,并分析了校准结果的测量不确定度,论证了校准方法的可行性。结果表明,在100 m斜距条件下,测量不确定度U=0.20 m(k=2),满足测量不确定度合格判定的要求,为超短基线水声定位仪量值溯源提供了技术保障。     

基于标准载荷测量法对原煤仓分炉煤计量装置示值误差测量的 不确定度分析与评定

原煤仓分炉煤计量是火力发电企业入炉煤耗数据来源的关键环节,原煤仓分炉煤计量装置因称量量程大而采用传统的标准砝码测量法很难进行量值溯源,本文采用基于标准载荷测量法对原煤仓分炉煤计量装置计量特性进行测量,并对测量过程产生的不确定度来源进行定性分析和定量计算。实验和计算数据表明,应用标准负荷传感器和高稳定性力源控制系统等组成标准载荷测量装置对原煤仓分炉煤计量系统进行量值溯源,其计量特性数据是可靠的。     

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.