微波消解-ICP-MS法测定海产品中的微量元素

本文采用微波消解电感耦合等离子体质谱法测定海产品中微量钴、铜、砷、钼、镉、锑、汞、铅等8种元素。8种元素回收率在90%~110%之间,RSD值均低于10%符合痕量分析要求,成功实现海产品中重金属的检测。     

茉莉花茶中铅镉元素的含量测定

本文比较了样品前处理微波消解法和干灰化法,优化了微波消解条件和石墨炉原子吸收光谱仪的各项技术参数,建立了同时测定茶叶中重金属Pb和Cd的新方法。测定12批茉莉花茶及茶渣中Pb、Cd两种重金属元素含量,计算了常规泡制条件下,该二元素的溶出率。结果表明：用微波消解-石墨炉原子吸收法测定Pb和Cd方法,铅、镉金属元素检出限分别为0.03μg/L和0.004μg/L,加标回收率在93.6%～97.2%之间。方法简便、可靠,能满足茉莉花茶中Pb、Cd分析检测的要求。检测的12批广西生产的茉莉花茶Pb含量均未超标,沸水泡制后Pb的溶出率为10.5%～18.6%,Cd的溶出率约为12.0%～34.7%。     

ICP—MS测定PM2．5中重金属不同消解方法的比对研究

采用电热板消解、微波消解和全自动石墨消解3种方法对大气PM2.5中的6种重金属用ICP-MS进行测定。全自动石墨消解法的加标回收率为94％～108％,RSD为1．5％～3．4％。实验证明该方法提高了样品前处理自动化程度,提高了操作规范化程度,减少待测物的损失,提高了方法的精密度和准确度,前处理简单,减轻了分析人员劳动强度,提高了工作效率,能更好地适应当前日益繁重的监测任务。     

微波消解测定污水中CODcr的比对实验

为研究在COD_(cr)测定中采用家用微波炉替代专用微波消解装置的可行性,采用美的MK823ESJ-PA型微波炉消解与专用WMX-Ⅲ-B微波消解装置消解,硫酸亚铁铵滴定法测定水样中COD_(cr)测定的比对研究,讨论消解功率、消解时间、C1~-干扰等因素对测定的影响,确定最佳的试验条件,当美的MK823ESJ-PA微波炉消解功率为中高火(616 W),消解时间为5 min时,精密度与准确度良好,RSD≤3.72%,加标回收率为94.22%-104.76%,与WMX-Ⅲ-B微波消解装置消解测定结果相对偏差≤3.76%。     

微波消解-石墨炉原子吸收分光光度法测定化妆品中微量砷

建立对微波消解-石墨炉原子吸收法测定化妆品中微量砷的方法.运用微波消解系统对化妆品进行消解,用石墨炉原子吸收法测定砷,利用加标回收试验来验证方法的准确性和精密度.结果表明,该方法快速、简便,回收率88%～104%,相对偏差5.3%,微波消解-石墨炉原子吸收光光度法可以运用到测定化妆品中微量砷.     

ICP-MS同时测定玛咖中16种稀土元素的研究

建立一种快速消解并同时测定玛咖中稀土元素的方法。采用微波消解样品,选择In作内标,电感耦合等离子体质谱法(ICP-MS)测定玛咖中稀土元素。对于所测的元素,校准曲线的相关系数>0.9990,回收率范围91.0%~111.0%,相对标准偏差0.4%~3.7%。该方法简便、快速、准确,灵敏度高,可用于玛咖中稀土元素的测定。     

水体重金属监测前处理系统的设计与实现

我国水体重金属污染严重,水质监测自动化程度不高。由于重金属的不同赋存形态对于监测结果有重要的影响,所以对水样进行前处理,明确重金属的赋存形态成为一个重要的过程,而现阶段此过程远远不能满足水体重金属监测自动化进程的需要。基于此,该项目开发研制一种可以实现对水样进行前处理的仪器,通过与单片机技术的结合,研发对水样的自动形态分离流程,实现重金属形态的初步分离,并达到单个水样的形态分离时间在30 min以内,形态分离误差绝对值小于等于10%总重金属元素量。     

一种坡面径流水样采集及流量测定装置

本文介绍了自行研制的一种坡面径流水样采集与流量测定装置。该装置通过翻斗式流量传感器、脉冲发生器及打点式计数器,实现坡面径流流量过程的自动测定;同时通过棘轮转盘、分水盘及集水容器,实现坡面径流水样的分布式采集。该装置集径流过程测定与水样采集于一体,可以采集和计量任意时段的径流水样及流量,与传统集总式水样收集方法相比,自动化程度高,管理方便;与现有径流测定方法相比,测量精度高,结构简单,不使用电力,更适于野外试验数据的采集。该装置可广泛应用于自然降雨及人工模拟降雨条件下坡面径流小区的土壤侵蚀过程与水土流失过程的监测实验,这在土壤侵蚀研究和水土流失治理上具有重要意义。     

在线消解-气相分子吸收光谱法测定水质中总氮

在线紫外灯加热消解和气相分子吸收光谱技术相结合,形成可实现水质中总氮包括有机氮和无机氮的全自动的检测系统。该系统可自动地执行采样、加热消解、数据测定、数据分析的全过程。通过试验测定,确定该系统的最佳测定条件。并且此系统消耗试剂量少(25mL),测定范围宽(0.150~100mg/L),检出限低(0.032mg/L),测定快速(8min),精密度高(RSD1.2%),实际水样的加标回收率均在97.1%~102.31%之内,可用于在线快速测定总氮。     

石墨消解连续光源原子吸收法测定废气中重金属

采用DEENA石墨消解仪对采集的废气样品进行前处理,利用contrAA700连续光源原子吸收光谱仪测定样品中重金属铜、锌、镍、铅、镉、锰。本试验优化了消解液的组合,使样品消解更完全,且克服了传统火焰原子吸收法需要更换空心阴极灯的缺陷,提高了分析速度。各元素的检出限分别为铜0.0025mg/m~3,锌0.0012mg/m~3,镍0.0038mg/m~3,锰0.0025mg/m~3,铅0.0075mg/m~3,镉0.0025mg/m~3。各元素的回收率分别为铜94.2%,锌102.5%,镍95.6%,锰104.1%,铅97.3%,镉95.3%。本方法具有较高的准确度,相比传统的火焰原子吸收法有更高的工作效率,适用于废气中多种重金属的同时测定。     

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.     

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.