气相色谱-质谱法同时测定蜂蜜中的双甲脒及其代谢物残留

建立了一种用气相色谱．质谱法(GC-MS)测定蜂蜜中的双甲脒及其代谢物(2，4-二甲基苯胺)残留的方法。蜂蜜样品用pH为11．0的水溶液溶解，其中的双甲脒和2，4-二甲基苯胺残留用正己烷超声波提取后直接用GC-MS测定。样品添加浓度在10μg／kg～200μg／kg时，双甲脒和2，4-二甲基苯胺的添加回收率在60％～120％之间，检出限均为10μg／kg。     

液相质谱法同时测定水产品中氯霉素和硝基呋喃类代谢物残留量的研究

本文研究建立了同时测定水产品中氯霉素和硝基呋喃类药物代谢产物的方法。先将与蛋白质结合的硝基呋喃类药物代谢物在酸性条件下水解,用2-硝基苯甲醛衍生后,以乙酸乙酯提取,经净化浓缩,用液相色谱质谱联用仪测定,内标法定量。样品中硝基呋喃类代谢物和氯霉素残留量检测的线性范围分别在0．25μg/kg～100μg／kg和0．1μg／kg～100μg／kg之间,最低检出限分别为0．25μg／kg和0．1μg／kg。添加回收率均在80％～110％之间。结果表明,该方法具有简单、快速、灵敏等特点,适用于水产品中硝基呋喃类代谢物和氯霉素残留量的同时分析。     

超高效液相色谱串联质谱法检测婴儿配方奶粉中的双氰胺

目的：建立一种婴儿配方奶粉中双氰胺残留量的超高效液相色谱质谱检测方法。方法：采用三氯乙酸溶液沉淀蛋白,处理液用watersSep—PakAc2固相萃取柱净化,用超高效液相色谱一串联质谱仪测定,外标法定量。结果：在0．10I．Lg／mL-50．0μg／mL范围内,线性良好,线性方程为y=2310．43×x＋1．01815,相关系数为0．999826（n=6）。加标回收率在90％～110％,相对标准偏差在10％1）2内。最低检出限为0．05mg／kg。结论：本方法操作简便,检出限低,重复性好,适合婴儿配方奶粉中双氰胺残留的测定。     

高效液相色谱法检测水产品中喹诺酮类药物残留

论述了高效液相色谱法检测水产品中恩诺沙星、环丙沙星、诺氟沙星、恶喹酸等合成抗菌剂残留的方法。样品以乙腈为提取剂，经脱脂、净化、浓缩，用流动相溶解。用高效液相色谱荧光检测器测定恩诺沙星、环丙沙星、诺氟沙星，利用荧光检测器的波长可变程序，又能同时检测恶喹酸。各标准曲线线性范围0．005-0．2μg／mL，线性相关系数r=0．9911—0．9943实验回收率68.6-82.3％，RSD在5．85％-8．12％（n=5），检测低限分别为1μg／Kg，2μg／Kg，2μg／Kg，2μg／Kg。     

反相离子对色谱柱后衍生法测定生物组织中四种生物胺的含量

采用反相色谱柱后衍生法测定肌肉组织中的酪胺、亚精胺、腐胺和尸胺含量。样品经0．6mol／L的高氯酸溶液匀浆提取；流动相为10mmol／L的辛烷磺酸钠溶液（pH5．2）与0．1mol／L乙酸钠溶液一乙腈（pH4．5），流速1mL／min；柱后衍生液为0．1％邻苯二甲醛（OPA）溶液（pH10．5～11．0），流速0．5mL／min；Discovery C18分离柱和保护柱；荧光检测器的激发波长和发射波长分别为340nm和450nm；采用62rain的梯度洗脱程序；外标法定量测定。该方法在0．2～10μg／mL的浓度范围内具有良好的线性关系，酪胺、亚精胺、腐胺、尸胺的方法回收率在85．2％～103．3％之间，最低检测限为0．2μg／mL。     

原子荧光法测定水产品中的无机砷

对原子荧光光谱法测定水产品中无机砷的不同前处理条件进行了分析和比较，获得最佳试验条件。在最佳试验条件下，无机砷的方法检出限为1．0μg／kg，RSD=1．5％。在0．5，1．0，2．0mg／kg三种添加水平下，方法回收率范围为88．0～96．0％。     

固相萃取-离子色谱法测定乳清粉中的硝酸盐

研究了采用固相萃取-离子色谱法测定乳清粉中的硝酸盐。用30mM的KOH溶液等度淋洗，流速为1．0mL／min，采用AS11-HC型阴离子色谱柱进行分析。在此检测条件下，硝酸盐有很好的线性（r=0．9999）。该方法的最小检出限为500μg／kg，回收率为87．5％-105％，RSD〈5％。实验结果表明，采用固相萃取-离子色谱法测定乳清粉中的硝酸盐，不仅样品前处理简便、快速，且检测结果准确。     

气相色谱-质谱法测定玉米中50种残留农药

粉碎好的玉米使用乙腈超声提取，再经碳十八和活性碳氨基串联固相萃取柱净化，采用GC—EI—MS的选择离子监测（SIM）方式和外标法定量方法，同时分析测定了玉米中的50种农药残留量。该方法回收率在62．8％-119．2％之间，相对标准偏差小于12．1％，50种农药的检出限（LOD）最小为0．8μg／kg，最高为7．2μg／kg。该方法快速、灵敏、准确。各项技术指标满足国内外农药残留检测的要求，能够应用于玉米试样中痕量农药残留的分析。     

依诺沙星在胶束体系中的荧光特性研究及应用

文章研究了依诺沙星在胶束体系中的荧光性质，发现十二烷基硫酸钠(SDS)对依诺沙星有较强的增敏作用，据此建立了胶束增敏荧光光度法测定痕量依诺沙星的新方法。经标准样品测定，依诺沙星浓度在0．03μg／mL～0．6μg／mL范围内与荧光强度呈良好的线性关系，检测限为0．01μg／mL，回收率为96．7％～99．2％，相对标准偏差为2．2％～3．9％。该法用于依诺沙星片剂的含量测定，结果令人满意。     

流动注射化学发光法测定复杂物料中的铌和钽

利用在碱性介质条件下，铌和钽对鲁米诺－H2O2－K3Fe（CN）6化学发光体系抑制作用，结合在线离子交换方法分离干扰离子，达到在线检测的目的。验证了铌和钽对化学发光体系抑制的线性关系。方法的检出限是铌：0．03μg／mL,钽：0．04μg／mL。测定铌和钽的线性范围为0．1－1μg／mL／。测定0．1μg／mL铌和钽9次的相对标准偏差分别为4．5％和5．1％。     

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.