滤膜中镍与铅盲样考核的质量控制

目的:探讨了盲样滤膜中镍与铅的测定,以及过程中实验准备、标准溶液和样品分析等环节的质量控制措施。方法:运用火焰原子吸收光谱法测定滤膜中的镍与铅。结果:滤膜中镍与铅盲样考核样品结果均准确。结论:严格质量控制下的滤膜中镍与铅的测定,是获得准确结果的有效方法。     

恒湿法测定TSP及HS—1型湿度控制装置

总悬浮颗粒物(TSP)是我国大气环境质量监测的必测项目之一.目前国内各级环境监测站均采用滤膜采样——重量法测定TSP。由于滤膜及采集于滤膜上的颗粒物在采样如称量过程中,受环境空气湿度影响很大,导致TSP监测结果的可靠性及可比性久佳。使用恒温、恒湿天平室固然能克服空气湿度对称量结果产生的影响,但此类天平室造价昂贵,运行费用高,目前尚难推广应用。为解决上述难题,保证监测数据质量,湖北省环保局将克服空气湿度对TSP监测质量的影响作为科研课题下达给湖北省环境监测中心站进行研究。经过近两年试验研     

X射线荧光光谱法在大气颗粒物无机元素分析中的应用

探讨了X射线荧光光谱法(XRF)在大气颗粒物无机元素测试中的应用。研究结果表明,测试时滤膜的有效直径对测试结果无明显影响,选择的测量直径对测试结果有一定影响,测量直径越大,能检测的元素种类越多。分别对某国产空白滤膜和某进口空白滤膜进行多次重复测样,结果国产空白滤膜的空白值总体比进口滤膜的空白值高,两种空白滤膜中Pd和Fe元素的空白值均较高;对颗粒物样品滤膜进行重复测试的相对标准偏差(RSD)在3%~17%。     

北京冬季大气颗粒物中铅的同位素丰度比的测定和来源研究

本文报道了北京市冬季（1998-1999年）大气颗粒物样品的无机多元素和铅同位素丰度比的测定数据。分别采用HR-ICP-MS和TOF-ICP-MS测定铅同位素丰度比,结果表明ICP-MS的测定精度可适用于大气中铅的来源研究。大气颗粒物样品中一些特征无机元素含量,如Br、Ti、Pb、Zn,与铅的同位素丰度比之间存在相关性。在铅含量高的样品中机动车尾气排放的贡献明显,在铅含量低的样品中土壤扬尘和燃煤飞灰的贡献增加;其中部分样品表现出来自西伯利来地区的长距离传输的特征。样品聚类分组结果结合气象信息可以得到合理解释。应用铅的同位素技术来研究北京市大气颗粒物中的铅的来源是可行的。     

低浓度颗粒物检测方法应用探讨

在《固定污染源废气低浓度颗粒物的测定重量法》 HJ 836-2017标准实际应用中,遇到了采样前颗粒物检测方法的选取,低浓度颗粒物采样前石英滤膜烘烤温度无法直接选择等问题。本文就常用有组织废气颗粒物检测标准的适用范围,采样前颗粒物检测方法确定,低浓度颗粒物采样前石英滤膜烘烤温度选择,低浓度颗粒物样品采集效率等问题展开探讨并提出解决方案。     

基于质谱技术的在线大气细颗粒物源解析研究——以江苏省淮安市为例

通过大气细颗粒物实时在线源解析仪器(质谱直接测量法),采集录入淮安市市区部分特征污染源排放成分谱,对淮安市秋季典型月份重点点位的细颗粒物进行实时在线源解析,获取高时间分辨的颗粒物源解析结果,以及重污染天气下颗粒物来源变化,评估重要污染源对淮安环境空气PM2.5污染的影响程度,为区域大气污染综合整治提供重要目标指向,同时也为淮安环境空气PM2.5重度污染实时预警与监控、大气污染源减排方案评估、污染事件监控等提供有效的在线监测技术平台,为管理决策提供有效的数据支撑和依据。     

淮安市大气细颗粒物来源解析研究

通过大气细颗粒物实时在线源解析技术(质谱直接测量法),采集录入淮安市市区部分特征污染源排放成分谱,对淮安市秋季典型月份重点点位的细颗粒物进行实时在线源解析,获取高时间分辨的颗粒物源解析结果,以及重污染天气下颗粒物来源变化,评估重要污染源对淮安环境空气PM2.5污染的影响程度,为区域大气污染综合整治提供重要目标指向,同时也为淮安环境空气PM2.5重度污染实时预警与监控、大气污染源减排方案评估、污染事件监控等提供在线监测技术平台,为管理决策提供有效的数据支撑和依据。     

徐州市区大气混合细颗粒物重金属Pb形态分析研究

以采集的徐州市区大气混合细颗粒物为研究对象,采用BCR法完成重金属铅的形态分析研究。徐州市区四个主要行政区的大气细颗粒物中铅主要形态为残渣态,占68%~84%;各样品中可氧化态铅含量最少,占5%~8%;弱酸提取态与可还原态比例相当;重金属Pb的化学形态分布特征为:残渣态弱酸提取态可还原态可氧化态;BI值在0.07609~0.2229之间,平均值为0.1353,综合分析徐州市区大气颗粒物中铅元素为生物可利用性元素,生物可利用性较为稳定,对人体危害少。     

电感耦合等离子体发射光谱标准基体匹配直接测定纯金中杂质元素

研究了纯金样品经王水溶解,标准基体匹配,直接用电感耦合等离子体发射光谱（ICP—OES）测定纯金中银、铜、铅、铁、锑、铋杂质元素的分析方法。实验表明,采用电感耦合等离子体发射光谱分析测定纯金中的杂质元素,并与GB/T11066-89的分析方法测定结果比较,具有分析速度快、准确度高、精密度好、检出限低的特点。     

超声波雾化-等离子光谱测定蔬菜中砷、铬、镉、铅的条件研究

本文研究了采用高温灰化植物样品,超声雾化器进样,并用ICP光谱仪进行砷、铬、镉、铅测定的最佳条件。以大白菜作基体材料,采用标准加入法制作工作曲线并进行了样品测定。本文建立的方法对蔬菜中As、Cr、Cd、Pb的检测提供了一种简便、快速、准确的途径。     

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.