高效液相色谱-串联质谱法测定烟草中马来酰肼残留量

建立了高效液相色谱-串联质谱（LC-MS/MS）测定烟草中马来酰肼农药残留的方法。烟草样品经盐酸溶液加热回流萃取,冷却后过膜稀释,多反应监测正离子模式测定,氘代马来酰肼同位素内标定量。结果表明,马来酰肼的定量限为0.27 mg/kg,加标回收率在90.3%~101.5%之间,相对标准偏差（RSD）小于5.5%;采用该方法对12个烟草样品进行检测,马来酰肼在其中10个样品中无检出,将有检出的2个样品与标准方法的测定值进行比较,结果显示两组数据的一致性较好,无显著性差异。该方法前处理简单、灵敏度高、稳定性好,适用于烟草样品中马来酰肼残留量的测定。     

二苯碳酰二肼分光光度法测定磁性材料中的铬(Ⅵ)

在硫酸介质中,二苯碳酰二肼可与铬(VI)发生显色反应生成紫红色的络合物,该络合物在540 nm波长处有最大吸收峰,由此建立测定磁性材料中铬(VI)含量的分光光度分析方法。本文对测定波长、显色pH值、显色剂用量以及显色时间等实验条件进行优化,在最佳实验条件下,络合物在540nm处的吸光度值与铬(VI)的浓度在0～0.3mg/L范围内呈良好的线性关系,其线性方程为A=0.839C-0.0048(c∶mg/L),相关系数r=0.9999;检出限为3.85×10~(-4)mg/L,回收率为94%～105%。采用碱浸煮方法提取磁性材料中的铬(VI),并用该方法对样品中铬(VI)的含量进行测定,并与SGS测得的结果进行对比。结果表明,该法的测定结果与SGS测得的结果相一致。该方法具有操作简便、快捷的优点,用于磁性材料中铬(VI)的测定,所得结果令人满意。     

电感耦合等离子体发射光谱法测定锆材中的铪、铁、铬

建立了电感耦合等离子体发射光谱法(ICP-AES)同时测定锆材中铪、铁、铬元素含量的方法。样品用硝酸-氢氟酸溶解,探讨了基体锆对元素铪、铁、铬以及铪、铁、铬相互之间的干扰情况,确定了铪、铁、铬元素最佳分析谱线分别为264.141nm,238.204nm,267.716nm。线性相关系数r≥0.9999,加标回收率均为95%~105%,铪、铁、铬的相对标准偏差小于3%(n=11)。该方法简便、快速、准确,满足锆材日常生产的检测要求。     

碰撞反应池-电感耦合等离子体质谱仪测定卷烟纸中的Na、K和Ca

为控制卷烟纸质量稳定性,建立了卷烟纸中Na、K和Ca的碰撞反应池-电感耦合等离子体质谱仪测定方法。方法采用10%硝酸溶液提取卷烟纸中目标物,采用离线内标、在线稀释法和耐高盐基质方法消除样品基体效应,采用碰撞反应池消除目标物的多原子干扰,用仪器自带新型正交检测器系统(ODS)提高样品动态测定范围。结果表明:方法检出限在之间0.08~0.20mg/kg,加标回收率在98.2~103.2之间,精密度小于3.4%。表明方法前处理简便快速、结果准确可靠,可用于卷烟纸中Na、K和Ca的同时测定。     

高效液相色谱仪串联三重四级杆质谱法快速测定姜茶中的姜黄素

建立了高效液相色谱串联三重四级杆质谱法(LC-MS/MS)测定姜茶中的姜黄素的方法。对样品的前处理方法及LC-MS/MS分析条件进行了优化,样品以甲醇为提取溶剂,超声提取,LC-MS/MS多反应监测模式(MRM)进行测定。姜黄素在0.005~0.1μg/mL范围内均呈良好的线性关系,相关系数为0.999;检出限为1.0μg/kg。标准加标回收试验,姜黄素添加浓度分别为5.0,10.0,20.0μg/kg,平均回收率为92.5%~102.5%,相对标准偏差(RSD)2.0%~2.5%。方法简便、快速、溶剂用量少,可消除姜油带来的干扰,结果准确可靠,适合进行批量样品的测定。     

聚乙二醇-二苯偶氮羰酰肼萃取分光光度法测定原油中的铬(VI)

研究了铬(VI)-二苯偶氮羰酰肼(DPCO)-聚乙二醇(PEG)体系的萃取行为和显色条件。在pH值为2.0的盐酸-氯化钾缓冲溶液中,络合物中的铬(VI)可被PEG相全部萃取,在PEG相中络合物的最大吸收峰位于550nm处,铬(VI)含量在0~25μg/10mL范围内符合比尔定律,表观摩尔吸收系数ε550=3.13×104L·mol-1·cm-1。人工合成样品中铬(VI)的平均回收率为96.84%。采用该方法测定了辽河原油和沙特原油中的铬(VI),其相对标准偏差分别为2.7%和2.8%,平均回收率分别为99.17%和96.64%。实验证明,该方法具有操作简便、分析速度快、精密度好的优点,是集萃取和显色为一体的测定原油中铬(VI)的较好方法。     

硫酸钡比浊法测定烟草中硫酸根(SO2-4)离子

烟草中硫酸根离子的含量会影响其燃烧性、质量和吃味.为快速准确大量地测定烟草中硫酸根离子的含量,本文介绍了硫酸钡(BaSO4)比浊法测定烟草中硫酸根离子的方法.将烟草样品进行干灰化后制成待测液,定容至100 mL,在弱酸性条件下,SO2-4和BaCl2作用生成溶解度很小的BaSO4白色沉淀.浓度在2～40mg/L范围内,其浑浊度与溶液中SO2-4浓度成正比,通过比浊法即可测定溶液中的SO2-4浓度.     

红外分光光度法测定处理后油气田含油污泥中石油类

建立了红外分光光度法测定油气田含油污泥中石油类的方法,并对方法中提取频率和时间、提取次数、硅酸镁吸附方式及填充高度、空白试验的制备进行优化。实验结果表明,方法检出限为0.02 mg/g,空白加标样品测定的精密度在2.2%~8.9%之间,加标回收率在92.5%~100%之间;实际样品测定相对标准偏差在2.4%~8.9%之间,加标回收率在88.2%~104%之间。本方法前处理操作简单,样品用量较少,测定结果的准确度和精密度较好,检出限低,可适用于处理后油气田含油污泥中石油类的准确测定。     

微波消解-电感耦合等离子体-质谱法测定塑料包装材料中痕量重金属元素

采用微波消解法预处理聚乙烯(PE)、聚丙烯(PP)、聚苯乙烯(PS)和丙烯腈-丁二烯-苯乙烯共聚物(ABS)等常用塑料包装材料样品,考察了消解介质、消解温度和保持时间对消解结果的影响,优化选择了电感耦合等离子体-质谱法(ICP-MS)的测定参数和内标元素.在选定的最佳消解和测定条件下,建立了微波消解-电感耦合等离子体-质谱法测定塑料包装材料中微量砷铅镉铬汞的方法.方法测定下限介于0.06～0.10μg/g之间,加标回收率在93%-106%之间,RSD＜8%.方法准确可靠,可用于实际样品分析.     

同位素稀释-电感耦合等离子体质谱法测定沉积物中铬和汞

采用同位素稀释-电感耦合等离子体质谱法（ID-ICP-MS）测定沉积物中铬和汞,分别以铬、汞单元素溶液标准物质标定⁵³Cr和²⁰²Hg浓缩同位素,将稀释剂与样品混合均匀后,加酸进行消解。对质谱测定过程的数据采集参数进行优化,探究基体效应以及H2和He两种模式对铬测定的影响。为防止汞的记忆效应干扰比值的测定,采用5 mg/L EDTA、2.5 mg/L Au溶液和3%硝酸交替冲洗管路系统,分别测定了²⁰⁰Hg/²⁰²Hg和¹⁹⁹Hg/²⁰²Hg两组比值,并比较测定结果。结果显示：积分时间为0.5 s时,同位素比值的测定精密度较好,对测定样品进行稀释能够消除质谱及基体效应干扰。H₂和He模式均适用于该类样品中铬的测定,²⁰⁰Hg/²⁰²Hg和¹⁹⁹Hg/²⁰²Hg两组比值对汞的测定结果无显著性差异,沉积物中铬和汞含量分别为81.7 mg/kg和0.471 mg/kg,相对标准偏差分别为0.35%和0.99%。采用美国NIST2709a标准物质进行方法验证,验证结果与标准值一致。该方法准确度高、精密度良好,适用于沉积物、土壤等基体样品中铬和汞的高准确度测定。     

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.     

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....     

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。     

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.