双阳极电化学氢化物发生原子荧光光谱法测定海水中的砷

用双阳极电化学氢化物发生原子荧光光谱法测定海水中的砷,不必通过化学氢化物发生,减少了化学试剂使用给环境带来的污染。对各种实验参数和干扰情况进行了详细研究。在选定的实验条件下,500μL进样量的As(Ⅲ)线性范围为5～20μg/L,检出限为0.36μg/L(信噪比S/N=3),20μg/L的As(Ⅲ)标准溶液平行进样13次,荧光信号(面积)的相对标准偏差(RSD)为2.22%,海水样品的加标回收率为95.7%～108%。本法灵敏度高、重现性好、结果准确可靠,可用于海水中砷的分析测定。     

在线镉柱还原-流动注射分析法测定水中硝酸盐/亚硝酸盐氮

采用在线镉柱还原-流动注射分析法同时测定水中的硝酸盐氮和亚硝酸盐氮.其中硝酸盐氮的方法线性范围为20.0-2000.0μg/L,相关系数r≥0.999,检出限为1.1μg/L,相对标准偏差为0.97%,样品测定频率为22样/小时,实际水样的加标回收率为94%-106%.亚硝酸盐氮的方法线性范围为2.0-200.0μg/L,相关系数r≥0.999,检出限为0.4μg/L,相对标准偏差为0.35%,样品测定频率为27样/小时,实际水样的加标回收率为91%-109%.此方法简单快捷,对于实际水样的测定结果令人满意.     

石墨炉原子吸收光谱法测定食品中的铅和砷

对石墨炉原子吸收光谱法测定食品中的铅和砷进行了研究,以硝酸镍作为基体改进剂,用HNO_3-H_2O_2消化样品,然后直接进样的分析技术。该法操作简便,取样量少且回收率高,样品基体干扰消除较完全,极大地改善了铅、砷的检出限,测定灵敏度大大提高。应用该法,铅、砷的线性范围均为0μg/L～80μg/L;回收率分别为101.5％,90.4％;变异系数分别为4.1％,5.6％;检出限分别为2μg/L,4μg/L。     

五参数全自动营养盐分析仪的研制与应用

本文研制了一种用来检测海水中营养盐含量的五参数全自劝分析仪.应用该仪器对海水中的正确酸盐、氨氮、可溶性硅酸盐、硝酸盐和亚硝酸盐含量进行了测定.其中正磷酸盐的线性范围,检出限和相对标准偏差分别为10-400 μg/L(r0.9997),0.7 μg/L和0.4%;可溶性硅酸盐的线性范围,检出限和相对标准偏差分别为50-2...     

流动注射分光光度法测定海洋沉积物间隙水中五项营养盐

建立了QC-8500流动注射分析仪测定海洋沉积物间隙水中铵盐、磷酸盐、硅酸盐、亚硝酸盐、硝酸盐五项营养盐的方法。该方法的检出限分别为0.90、1.18、1.80、0.33、0.36μg/L,线性范围分别为2.50~500μg/L、1.00~100μg/L、10.0~2000μg/L、0.50~15.0μg/L、0.50~15.0μg/L,相对标准偏差均在5%以内,各项指标均满足海洋调查规范(GB12763.4-2007)对五项营养盐分析的质量控制要求。与国标方法实验结果对比显示两种方法没有显著性差异。并对水合物区真实样品进行了测定及加标回收实验,回收率均在94%以上,保证了营养盐数据的准确性和真实性。     

双道原子荧光法同时测定云母钛珠光颜料中痕量砷和汞

采用混合酸(6mL盐酸,2mL硝酸和5mL氢氟酸)消解云母珠光颜料样品,在消解液中加入硫脲溶液后,以双道原子荧光法同时测定了样品中痕量砷和汞。砷和汞的线性范围分别为0.5～10μg/L和0.1～2.0μg/L,相关系数为0.9993和0.9997,检出限为0.0215μg/L和0.0035μg/L。两个水平加标回收率测试结果为84.4～102.5%。实际样品中砷和汞的含量分别为1.4777mg/kg和0.0162mg/kg,对实际样品平行测定7次,荧光强度的相对标准偏差分别为4.28%和5.84%。两元素同时测定可以提高分析效率,节省化学试剂,测量效果令人满意。     

微波消解、水浴锅消解-原子荧光法测定硒

本文通过微波消解和水浴锅消解土壤和水质样品,原子荧光光谱仪测定土壤和水质样品中的硒。结果表明,以上两种消解方法均能满足土壤和水质样品中硒的测定,分析精密度好,准确度高。微波消解原子荧光测定土壤的检出限为0.05μg/L,王水水浴锅消解土壤的检出限为0.05μg/L,王水水浴锅消解水质样品的检出限为0.07μg/L,相对标准偏差小于6.0%,回收率为87.1%108%。相比之下,如果只测定土壤或水质样品中的硒,则选择水浴锅消解较为简便,如要同时测定土壤中的其它重金属,则选择微波消解更为简便     

分段流动分析法测定海水中的硝酸盐氮

采用分段流动分析法测定海水中的硝酸盐氮,通过实验,方法检测限为0.03μg/L;对两种不同浓度的标准样品分析,测定值在其保证值范围内,相对标准差<2%,准确度和精密度均较好;采集6个广西近岸海域监测点的水样与国标法进行对比实验,结果有良好的一致性;循环周期约100s,每小时可测定36个样品,分析速度快,尤适合大批量样品的测定.     

流动注射法测定饮用水中氰化物

目的建立测定水中氰化物的流动注射分析法。方法一般样品直接进样,如果样品中含有游离余氯时先用无水亚硫酸钠溶液除氯后再测定。应用FIA6000型全自动流动注射分析仪直接在线蒸馏测定饮用水中氰化物。结果该测定方法相关性好,相关系数为0.9999,线性范围宽2.0～90.0μg/L,精密度RSD为1.95%～2.30%,方法检出限为0.156μg/L。结论方法简便、快速,干扰少,灵敏度高,有较高的实用价值,特别适合大批样品的测定。     

流动注射在线测定环境水样中的氰化物

利用流动注射在线测定环境水样中的氰化物（CN）。实验结果表明,该方法能够满足日常水质分析的要求,做到快速准确。测定范围为2.0-100μg/L,检测限为0.783μg/L,分析速率为18个样/h,加标回收率为：96.7%-102.6%.     

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.