QuEchERS-UPLC-MS/MS法测定蔬菜中5种植物生长调节剂

应用超高效液相色谱-串联质谱联用(UPLC-MS/MS)技术,建立了同时检测蔬菜中5种植物生长调节剂的检测方法。样品经乙腈提取,QuEchERS法净化后,Waters HSST_3超高效液相色谱柱分离,方法回收率在73.8%~96.3%之间;相对标准偏差(n=3)范围为1.4%~8.5%。方法检出限范围为1.1×10~(-3)~1.86×10~(-2)mg/kg。     

超高效液相色谱-串联质谱法测定食品接触塑料中3种苯并三唑类紫外吸收剂的特定迁移量

建立了超高效液相色谱-串联质谱法测定食品接触塑料中3种苯并三唑类紫外吸收剂特定迁移量的检测方法。样品使用蒸馏水、3%(w/v)醋酸、10%(v/v)乙醇溶液、90%(v/v)乙醇溶液、橄榄油浸泡处理,水基食品模拟物直接进样,橄榄油用甲醇正庚烷提取后进样。用Waters ACQUITY UPLC BEH C18(100×2.1mm,1.7μm)色谱柱分离,甲醇和0.1%(v/v)甲酸水溶液为流动相进行梯度洗脱,在电喷雾正离子模式下,采用多反应监测(MRM)模式进行定性和定量分析。结果表明,3种苯并三唑类紫外吸收剂线性关系良好,相关系数(r)均大于0.991,检出限为0.6~4.0μg/kg,5.0、20.0和50.0μg/L水平下的加标回收率在65.2%~87.2%之间,相对标准偏差在1.2%~4.0%(n=6)之间。方法准确、简便,可用于食品接触塑料中3种苯并三唑类紫外吸收剂的快速筛查和定量分析。     

超高效液相色谱-二极管阵列检测法测定油基类保健食品中的维生素K2的含量

建立了超高效液相色谱-二极管阵列检测法(UPLC-PDA)测定油基类保健食品中维生素K 2(七烯甲萘醌)含量的方法。试验显示维生素K 2对紫外光、强碱条件敏感。样品经脂肪酶酶解后,皂化、萃取、复溶,C 18色谱柱(100×2.1 mm,1.7μm)分离,甲醇为流动相,流速为0.3 mL/min,254 nm检测。本法在1.0~20.0 mg/L线性关系良好,R 2=0.9999。当取样量为1 g,定容至10 mL时,方法LOD为1μg/g,LOQ为3μg/g,RSD为1.2%,加标回收率为98.7%~102.2%。该法准确、高效,对各类保健食品具有良好的普适性。     

超高效液相色谱-串联质谱法测定食用菌中农药多残留研究

采用超高效液相色谱-串联质谱(UPLC-MS/MS)技术,建立了同时检测食用菌中10种农药的多残留检测方法。样品经乙腈提取,氨基固相萃取柱净化,Waters HSST3超高效液相色谱柱分离,进入电喷雾串联四极杆质谱进行检测,采用多反应监测(MRM)分析,对液质分离条件和样品前处理条件进行了优化。结果表明10种农药在10~200μg/L范围内线性良好(r≥0.9985)。在0.01、0.05mg/kg浓度范围内,平均加标回收率在80.3%~102.6%之间;相对标准偏差RSD(%)≤9.8%。该方法的最低检出限范围为1.72×10-4~9.28×10-3mg/kg。该方法简便、快速、灵敏、净化效果好,测定结果满足食用菌农药多残留的检测要求。     

高效液相色谱法测定去叔丁基杯[6]芳烃的含量

目的 :建立测定去叔丁基杯[6]芳烃含量的高效液相色谱方法。方法 :采用Diamonsil C_(18)色谱柱色谱柱(250 mm×4.6 mm,5 um);流动相为甲醇(加入0.1%三氟乙酸);流速:1.0 m L/min;检测波长为206nm;柱温40℃;进样体积:20μL。结果 :去叔丁基杯[6]芳烃主峰分离良好,HPLC测定的线性范围为10.0~60.0μg/m L(r=0.9998),该方法在仪器精密度、日内精密度、日间精密度以及重复性方面RSD均在2%以下。结论 :用高效液相色谱法对去叔丁基杯[6]芳烃进行含量测定,方法简单,结果准确可靠。     

SPE-UPLC-MS/MS法测定牛奶中β-内酰胺类药物残留

本试验应用固相萃取技术(SPE),结合超高效液相色谱-串联质谱联用仪(UPLC-MS/MS),建立了快速测定生鲜乳中!-内酰胺类药物残留的方法。样品经乙腈提取,Oaiss PRiME HLB固相萃取小柱净化后,以0.1%甲酸乙腈溶液和0.1%水溶液为流动相,Waters C_(18)色谱柱进行分离;多反应监测(MRM)模式,外标法进行定量。方法回收率在70.1%~95.5%之间;相对标准偏差(n=3)范围为1.0%~9.1%;线性范围为0.002~0.100mg/L;检出限为0.1~0.6μg/kg;定量限为0.3~1.8μg/kg。表明该方法专属性强、灵敏度高,适用于生鲜乳中β-内酰胺类药物残留的测定。     

HPLC-MS联用法测定猪肉组织中5种磺胺类药物的残留

建立一种用高效液相色谱与质谱联用法测定猪肉组织中磺胺类药物残留的方法,该方法检测猪肉中的磺胺类药物快速、准确。样品经2%的醋酸水溶液提取后通过固相萃取柱净化,用甲醇洗脱,吹干,然后用流动相A溶解,用DAD及MS检测器检测。采用AgilentHC-C18(4.6×250mm,5μm)色谱柱,以0.3%甲酸和5%甲醇的水溶液-0.3%甲酸的甲醇溶液为流动相进行梯度洗脱。在添加水平为0.1mg/kg,0.2mg/kg,0.5mg/kg时,对于不同的药物,回收率范围为55.3%~102.8%,相对标准偏差在0.79%~10.4%之间,方法的最低检出限为0.1~0.5ppb。通过大量的实验结果表明,该方法适用于猪肉组织中磺胺类药物的残留测定。     

婴儿配方奶粉中叶黄素测定

建立高效液相色谱法测定婴儿配方奶粉中叶黄素的检测方法。采用色谱柱为Carotenoid C30色谱柱（250.0mm×4.6mm,5μm）,流动相为甲醇和甲基叔丁基醚,梯度洗脱,紫外检测器,检测波长445nm。结果表明,叶黄素浓度在0.05～2.0μg/mL之间呈线性关系,线性方程为：y=379874.03X＋14289.56,相关系数R2=0.9990;奶粉的含量为50～500μg/100g时,回收率在92.8～103.5%之间,RSD%在1.2～3.5%之间;检出限为5μg/100g。该方法操作快捷简便,结果准确。     

超高效液相色谱-质谱法测定有机农药制剂中烷基酚聚氧乙烯醚

建立了超高效液相色谱-质谱法(UPLC-MS)测定乳油、微乳剂、悬浮剂、水乳剂、可溶液剂和水剂6类有机农药液体制剂中辛基酚聚氧乙烯醚和壬基酚聚氧乙烯醚的含量。样品经甲醇超声辅助提取,稀释后采用BEH C18色谱柱(2.1 mm×100 mm×1.7μm)分离,以10 mmol/L乙酸铵溶液和甲醇为流动相,梯度洗脱,柱温为30℃,流速为0.3 mL/min,电喷雾电离正离子模式,选择离子监测(SIR)模式定量。结果表明,辛基酚聚氧乙烯醚(OPEO)和壬基酚聚氧乙烯醚(NPEO)在50~10000μg/L浓度范围内的线性关系良好(r>0.999),在5、20、100 mg/kg添加水平内的添加回收率为81.8%~115.5%,相对标准偏差为1.1%~9.8%,两种化合物的定量限均为50μg/L。该方法操作简便、快速、准确、稳定性好,适用于有机农药中烷基酚聚氧乙烯醚类助剂的定性分析和定量检测。     

亲水性Obelisc R液相色谱-串联质谱法测定猪肉样品中氨基糖苷类药物残留

建立了高效液相色谱-串联质谱法测定猪肉中9种氨基糖苷类药物(壮观霉素、潮霉素B、双氢链霉素、链霉素、阿米卡星、卡那霉素、安普霉素、妥布霉素、庆大霉素)残留量。待测样品中的氨基糖苷类药物经磷酸盐缓冲溶液提取,调节pH值后,经SupelMIP~ SPE-Aminoglycosides分子印迹固相萃取柱净化、浓缩、定容,然后采用Obelisc R高效液相色谱柱分离,以串联质谱法正离子模式检测。该方法在20~1 000μg/L范围内线性关系良好。在线性范围内,分别进行高、中、低3个浓度的添加实验,样品的回收率在76.9%~89.4%之间,相对标准偏差在3.56%~11.4%之间。该方法简便、快速、准确,可以满足猪肉中氨基糖苷类药物残留的测定需求。     

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...     

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。     

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.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.