电感耦合等离子体质谱法（ICP-MS）测定运动员食品中铅、砷、镉、铜

以Sc、Ge、In、Bi作内标，采用电感耦合等离子体质谱法(ICP-MS)测定运动员食品中铅、砷、镉、铜。实验表明，方法的线性范围宽，线性相关系数均大于0.999。样品的加标回收率均在88.5%～107.5%，相对标准偏差均在5.0%之内。测定了GBW08503b、NBS1568、GBW08571标准参考物质中上述元素，测定值均在标准值范围内。该方法简单、快速、灵敏、准确，适用于运动员食品中铅、砷、镉、铜含量的分析。     

方法联用测定铬铁中的铬、硅、磷含量

建立一种同时测定铬铁中主量、次量元素的方法。样品经溶解后,用电感耦合等离子体发射光谱法(ICP-AES)测定铬铁中的硅、磷含量,用自动电位滴定法测定铬铁中的铬含量。该方法用于2种标准物质GBW01425a和GSB03-1058-1999的实际分析,Cr、Si、P的测定值与标准值吻合,RSD(n=11)为0.09%～3.92%;Cr、Si、P的回收率为100.45%～105.88%。与现行国标方法相比,分析周期短,适用于大宗铬铁进出口检验的要求。     

中药材不同前处理方法中5种重金属含量分析

用微波消解样品、电感耦合等离子体质谱(ICP-MS)法测定14种中药材的试液、药渣及煎煮液中的铜、铅、镉、汞、砷含量。用茶树叶GBW08513、灌木枝叶(GBW07605)及灌木枝叶(GBW07602)三个国家一级标准参考物质验证方法的精密度和准确度,相对标准偏差(n=7)≤8.01%。该方法简便、快速、准确、可靠,适合大批量检测。测定结果表明,按中医医嘱进行中药材煎煮法处理后的煎煮液中测定的重金属元素含量都合格,可安全食用。     

中国成年男子肺及肾脏中的Hg、I

在我国四个不同膳食类型地区,采集16例急死正常成年男子尸体的肺和肾脏样品。采用HNO3 H2O2为消解液,微波消解样品,用ICP-MS法直接测定样液中Hg、I、Mo等25种微量元素,内标元素Re可补偿机体效应。对猪肝标准物质(GBW08551)及人发标准物质(GBW09101)测定,测得值与标准值吻合。方法简便,快速,灵敏,准确。     

电感耦合等离子体质谱测定土壤中的有效钼

采用电感耦合等离子体质谱仪,以草酸-草酸铵浸提土壤中的有效钼,不经分离富集,直接测定土壤样品中的有效钼。方法检出限可达0.042μg/g,通过对国家土壤有效态一级标准物质测试,测定结果基本一致;GBW 07413标准物质11次测定的相对标准偏差(RSD)为0.76%。     

采用四种不同方法测定植物中氮含量的检测方法对比

作者选用两个国家一级植物标准物质柑橘叶(GBW10020)、茶叶(GBW10016)和自制两个植物样品菠萝蜜叶和扁桃叶作为样品,分别用杜马斯法、凯氏定氮法、自动凯氏定氮仪法、分光光度法对上述四种样品进行氮含量的测定,比较其测定结果,分析了不同方法的优缺点、检测成本及适用性.     

密闭消解电感耦合等离子体质谱法测定铝土矿中锂、锶、镓、铌、钽、锆和铪

采用电感耦合等离子体质谱,硝酸-氢氟酸增压密闭消解样品,实现了铝土矿中锂、锶、镓、铌、钽、锆和铪的同时测定。实验中探讨了最佳的消解程序,选择适当的同位素,并用铑、铼做内标元素,有效地抑制了分析信号的漂移。各元素的检出限在0.02～1.00μg.g-1,相对标准偏差在0.63%～1.63%,Nb,Ta,Hf的回收率在99.2%～99.6%;该方法经国家标准物质（GBW07177,GBW07182,GBW07180）验证,各元素测试结果与真值很接近。     

基于阳极溶出伏安法(HM-3000P)测定食品中镉(Cd)的应用

用硝酸-高氯酸高温加热体系消解大米和圆白菜样品,基于阳极溶出伏安法采用便携式重金属分析仪(HM-3000P)测定样品中镉(cd)的含量,其中大米检测结果的重复性误差RSD=2.86％,且通过与原子荧光光谱法检测比较发现结果基本一致.在HM-3000P内置的最佳测定参数下,镉(Cd)线性范围是0.1 μg/L～40 mg/L,检出限是0.1 μg/L.此法测定大米(GBW10010)、小麦粉(GBW08503b)、菠菜(GBW10015)、圆白菜(GBW10014)、绿茶(GBW10052)五个国家标准物质,测得值均在标准值的置信范围区间.因此,HM-3000P为检测食品中镉(Cd)含量提供了一种简单可靠的途径.     

电感耦合等离子体发射光谱检测烟叶样品中的钠钾钙镁

采用电感耦合等离子体发射光谱(ICP-OES),建立了快速检测烟叶样品中钠(Na)、钾(K)、钙(Ca)、镁(Mg)4种营养元素的方法。结果表明:①径向模式下,样品空白检测值为0.000～0.007mg/L,干扰较小,强度不易饱和,检测范围更宽;②4个元素标准曲线相关系数r均大于0.999,方法检出限在0.005～0.014mg/L之间;③方法精密度为0.19～1.43%,GBW07602的检出结果均符合质控要求。     

压力消解、HG-AFS法测定固体样品中的砷和铅

采用增压消化罐进行样品预处理,HG-AFS法测定了固体样品中的AS和Pb。探讨了酸介质、称样量、还原剂浓度及酸度等因素对测定结果的影响,优选出仪器最佳工作条件,并用此方法对标准物质小麦(GBW08503)和标准参考物质桃叶(82301)进行分析,结果表明,小麦中As和Pb的测定结果均在标准含量范围之内,桃叶中As和Pb的测定值与推荐值之间的相对偏差分别为2.35％和1.04％。     

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.