毛细管气相色谱法测定塑料包装及其内食品中酞酸酯

建立了用毛细管气相色谱-氢火焰离子化检测器测定塑料食品袋及袋内包装食品中5种酞酸酯（邻苯二甲酸二甲酯（DMP）、邻苯二甲酸二乙酯（DEP）、邻苯二甲酸二丁酯（DBP）、邻苯二甲酸二正辛酯（DOP）和邻苯二甲酸二（2-乙基己基）酯（DEHP））的方法。样品用无水乙醇超声提取，经干燥脱水过0．45μm滤膜过滤，直接注入气相色谱仪进行分析。用保留时间定性，外标法定量。5种酞酸酯的回收率为71．5％～125．5％；精密度（RSD）为1．6％～3．2％；DMP、DEP、DBP、DOP和DEHP的检测限分别为0．18ng、0．13ng，0．13 ng、0．15ng和0．14 ng。该方法准确度和灵敏度高，样品用量少，前处理简单，可同时测定塑料食品袋及包装内食品中5种酞酸酯。     

微波消解—氢化物原子荧光光谱法测定番茄酱中的铅

本文采用微波消解技术溶解番茄酱，以氢化物—原子荧光光谱法测定铅，研究并确定了酸介质及其浓度、还原剂用量以及番茄酱中常见元素对测定的干扰情况；以及氧化剂的选择、使用方法进行了讨论。方法的线性范围为0-150ng／mL，检出限为0．4ng／mL，精密度为2．6％～3．1％，回收率为92％-104％。     

ICP—AES法同时测定自来水中的钙、镁、钠

本文采用ICP—AES法同时直接测定自来水中的钙、镁、钠。精密度为0．4％-0．7％；回收率为97％-104％。试验证明该方法完全能够满足水质监测的需要。     

原子荧光法同时测定水产品中砷和汞

采用微波消解样品，原子荧光法（AFS）同时测定水产品中砷和汞。研究了仪器条件、酸度、硼氢化钾浓度等对测定的影响，砷和汞的检测限为0．05μg／L和0．01μg／L；相对标准偏差为1．46％和1．51％；回收率为84.9％～112．5％和90．0％～115．0％，用该方法分析水产品，结果满意。     

微波消解电感耦合等离子体质谱测定糖果中钛含量

建立了电感耦合等离子质谱（ICP-MS）测定糖果中钛含量的方法,从而推断出食品生产中添加二氧化钛量及食品中的钛残留量是否超标。结果表明,该方法在1．0～100．0g／L范围内呈良好线性关系（r=0．9999）,加标回收率为97．7％～102．2％,测定结果的相对标准偏差为1．04％（n=6）。该方法检出限低,操作简便、快捷、准确,线性范围宽,适用于糖果等食品中钛含量的准确测定。     

蒸气发生-原子荧光光谱法测定绿色食品生产基地中的砷、锑和汞

研究了VG—AFS法测定土壤样品中微量As、Sb和Hg在两种不同方式王水消解方法时对分析结果的影响，以及优化了各种分析条件，拟定了分析方法。本法经国家一级土壤标样测定验证，结果与标准值吻合。测得砷、锑和汞的方法检出限分别为0．028ug/g、0．028ug／g和0．009ug/g；相对标准偏差(n=6)分别为1．9％、5．5％和5．0％。     

原子荧光光谱法测定焦亚硫酸钠中微量砷

建立了用原子荧光光谱法测定食品添加剂焦亚硫酸钠中微量砷的方法。方法灵敏度高，准确度好。在选定的试验条件下，荧光强度与砷浓度在0～150ng/mL范围内成线性关系，相关系数0．9993，检出限0.4ng／mL，回收率98．0％～100．5％，相对标准偏差不超过3．7％     

FAAS法对人体血样中铅、锌和铁的测定与研究

本文使用了火争原子吸收光谱法测定人体血样中铅、锌、铁的方法。确立了最佳样品处理方法和仪器的工作条件。在拟定的实验条件下，测定铅的特征浓度为0．010ug/ml/1%吸收；测定锌的特征浓度为0．002ug/ml 1/%吸收；测定铁的特征浓度为0．014ug/ml／1％吸收。回收率分别为铅99．2％－101．5％，锌92．5％－98．6％，铁98．8％－103．4％。     

火焰原子吸收光谱法测定锡铅焊料中铜铁锌

研究了火焰原子吸收光谱法测定锡铅焊料中铜、铁、锌的方法。样品采用盐酸和过氧化氢溶解，对测定条件进行了研究，不用分离铅、锡，直接测定此三种元素。方法简便，能满足锡铅焊料测定的要求。相对标准偏差1．1％—3．0％，回收率96％—103％。     

工作场所空气中碳酸镁离子色谱分析方法的研究

目的：建立工作场所空气中碳酸镁的离子色谱测定方法。方法：滤膜采集空气中的碳酸镁，样品经EDTA络合剂螯合后，离子色谱测定。结果：空气中碳酸镁浓度在0．073mg／m^3-72．92mg／m^3，变异系数均小于2％；回归方程y=0．4397x-0．0256，r=0．9998；检出限0．01μg／mL；回收率为大于等于90％。结论：本方法适合用于工作场所空气中碳酸镁浓度的测定，并能实现与空气中阴离子同时分析测定。     

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.     

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.