高效液相色谱-电感耦合等离子体质谱联用技术测定畜禽肉制品中八种砷形态化合物

建立了畜禽肉制品中三价砷［As(Ⅲ)］、一甲基砷(MMA)、二甲基砷(DMA)、五价砷［As(Ⅴ)］、阿散酸(p-ASA)、 洛克沙砷(ROX)、4-羟基苯砷酸(4-HPAA)和4-硝基苯砷酸(4-NPAA)等砷形态化合物的高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)分析方法。以甲醇-水(1∶1,V/V)作为提取剂,采用超声水浴对样品进行前处理,选取Dionex IonPac AS14 阴离子交换柱作为分析柱,50 mmol/L (NH₄)₂HPO₄(pH 7.3)为流动相,对畜禽肉制品中的砷形态化合物进行分析测定。结果表明,8种砷形态化合物的线性范围为1~300 μg/L,相关系数(R²)均大于0.999,检出限为0.1~0.5 μg/L。以精密度考察方法重现性,相对标准偏差（RSD）均小于5%,方法加标回收率在80.8%~105.7%之间。通过对实际样品的分析测定,发现在畜禽肉制品中的有机砷制剂主要为三价砷阿散酸和洛克沙砷,另外还有一种未知的砷化合物,有待进一步研究确认。     

液相色谱—原子荧光光度计联用测定三种含砷药物的形态

本文以AF-610D2色谱-原子荧光联用仪为检测平台,建立了分离含砷药物中对氨苯基砷酸(PASA)、2-硝基苯基砷酸(NPAA)和4-羟基-3-硝基苯基砷酸(NHPAA)三种有机砷制剂的砷形态分析方法。在优化色谱分离和检测条件下,浓度均为100ng/mL的三种砷药物混合溶液7次重复测定,色谱峰的相对标准偏差(RSD)分别为1.74%、1.02%和1.62%;100μL进样线性范围在10-2000ng/mL之间,相关系数均可达0.999以上;检出限分别为0.22ng/mL,0.24ng/mL和0.42%。     

土壤中砷的形态分析方法研究及应用

用高效液相色谱-氢化物发生-原子荧光法分离和测定土壤中As（Ⅲ）、DMA、MMA、As（Ⅴ）,考察（NH4）2HPO4溶液浓度、pH值、流速对分离的影响,HG-AFS分析条件对峰信号的影响及不同提取剂对土壤中砷形态的提取效果,在确定好各种操作参数下各组分在13min内得到很好的分离,检出限0.43-0.67μg/L,样品加标回收率89.9%～104.5%,相对标准偏差4.88%～6.52%,样品提取率73.5%～82.7%。     

超声辅助酶法提取-高效液相色谱-原子荧光光谱联用技术测定大米中6种硒形态

建立了同时检测大米中6种硒形态的超声辅助酶法提取-高效液相色谱-原子荧光光谱联用检测方法(HPLC-AFS)。利用链霉蛋白酶E,超声提取30min,使用Hamilton PRP-X100色谱柱(250mm×4.1mm,10μm),99%的5mmol/L pH为4.70柠檬酸的缓冲溶液和1%的甲醇洗脱,原子荧光检测,结果显示:各目标物方法检出限在0.5～3.1μg/L,相关系数≥0.9992,回收率为80%～114%。本方法适用于大米中6种硒形态检测。     

HPLC-ICP-MS法分析太湖沉积物中砷的形态及分布特征

以0.3 mol/L磷酸和0.1 mol/L抗坏血酸为提取试剂,对沉积物样品进行微波萃取。以2.0 mmol/L NaH₂PO₄/0.2 mmol/L EDTA(pH 6.0)为流动相,采用高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)联用技术测定萃取液中As（Ⅲ）、As（Ⅴ）、MMA和DMA的含量。4种形态砷的色谱峰在10 min内可以得到完全分离,标准曲线线性良好,样品的加标回收率范围为94.2%~110%,样品中砷形态的提取效率为80.4%~98.7%。研究表明,太湖表层沉积物中的砷主要为无机形态,未检出有机砷形态,As（Ⅴ）形态的含量高于As（Ⅲ）,说明太湖表层沉积物基本上处于氧化性沉积环境中。近20年来,太湖湖底沉积物中砷的含量有了显著增加。检测的沉积剖面沉积物中砷的形态亦为无机形态,各沉积剖面沉积物中砷形态的相对比例没有显著差异。     

HPLC-ICP-MS法分析测定富硒保健品中的硒形态

确定保健品中硒形态(亚硒酸根、硒酸根),采用水浴振荡提取的前处理方法,液相色谱柱选用IonPac AS11(250 mm×4 mm)分析柱+IonPac AG11(50 mm×4 mm)保护柱,对其进行分离,ICP-MS检测。本文探讨色谱柱、流动相、样品前处理方法的选择,并且在液体、胶囊、鱼油、片状保健品中进行加标回收实验,亚硒酸根、硒酸根的回收率为79.7%-116.4%,精密度(RSD)小于15%。该方法具有灵敏度高、干扰小、样品前处理简单等优点,可以用于保健品中硒形态的筛查和测定。     

高效液相色谱-电感耦合等离子体质谱法分析经牛黄解毒片暴露后大鼠血清中砷形态

采用高效液相色谱-电感耦合等离子体质谱联用技术测定经牛黄解毒片暴露后大鼠血清中的砷形态。以乙腈为提取剂,采用60 ℃水浴超声提取法对血清样品进行前处理,提取液以13 000 r/min离心10 min,上清液过0.45 μm滤膜。采用Dionex IonPac AS19分析柱(250 mm×4 mm×10 μm),以20 mmol/L碳酸铵(pH 9.7)-3%甲醇溶液作为流动相,分析经牛黄解毒片暴露后大鼠血清中的砷形态。结果表明,AsB、DMA(Ⅴ)、As(Ⅲ)、MMA(Ⅴ)和As(Ⅴ)的检出限分别为0.05、0.05、0.08、0.10和0.10 μg/L;线性相关系数（R²）大于0.999;加标回收率在86.3%~109.2%之间,相对标准偏差RSD小于5%。通过对经牛黄解毒片暴露后大鼠血清中砷形态的分析发现,DMA(Ⅴ)和U1为主要的砷形态,另外含有少量的AsB和U2。该方法灵敏度高、提取效率好,实现了多种已知和未知砷形态的同时分离,可为研究牛黄解毒片在大鼠血液中的代谢提供技术支持。     

用液相色谱-等离子质谱联用法测定有机胂制剂中的无机砷含量

砷的毒性大小顺序为As3+>As5+>R-As-X.,有机胂作为动物抗病原微生物和促生长类饲料添加剂,在饲料中应用极为普遍。但有机胂中无机砷含量有多高,对环境的影响有多大,畜产品中砷的残留有多高等问题都无相应的检测数据加以论证。因此,了解有机胂制剂中的无机砷含量与有机胂制剂分解速度意义重大。应用液相色谱-等离子质谱联用的方法分析样品中的无机砷。采用20%(体积比)甲醇水溶液作为萃取剂,将样品进行预处理,再以5mmol/L四丁氢铵,2mmol/L丙二酸和5%(体积分数)甲醇水溶液作为流动相(pH5.9),C18色谱柱(150mm×4mmi.d.,5μm)将样品萃取液进行液相色谱分离,最后进入等离子质谱仪定量分析。测定对氨基苯胂酸和硝基羟基苯胂酸无机砷含量。     

毛细管电泳-电感耦合等离子体质谱法对砷形态分析

建立了使用毛细管电泳与电感耦合等离子体质谱联用技术(CE-ICP-MS)对5种形态的砷化合物砷甜菜碱(As B)、砷胆碱(As C)、三价砷(As3+)、二甲基砷(DMA)和一甲基砷(MMA)进行形态分析的实验方法。结果表明,使用摩尔体积比为4:1的50mmol/L H3BO3~12.5mmol/L Na2B4O7混合溶液作为缓冲溶液,在p H值为9.1,分离电压为18KV的实验条件下分析结果最为理想。5种砷化物的峰面积相对标准偏差(RSD)在5%以内,检出限(3S/N)为1.6ug/L~3.1ug/L。应用该方法成功地对虾肉中的砷化物进行了分析,回收率为88%~112%。该方法具有分析速度快、灵敏度高等优点,可用于虾肉样品中砷元素的形态分析。     

不同浸提方法对土壤及蜈蚣草中砷形态浸提效果

采用几种常见浸提方法对砷污染土壤和蜈蚣草样品进行处理,并使用LC-AFS测定砷形态,重点考察不同浸提方法对样品砷浸提效果的差异,以及其形态分布特征。结果表明:土壤和蜈蚣草中砷主要以As(Ⅲ)和As(Ⅴ)的无机形态存在。土壤、蜈蚣草根和蜈蚣草叶中As(Ⅲ)所占比例分别为11.6%,24.2%和73.8%。磷酸150℃高温浸提对土壤的浸提效率最高,可达41.0%;甲醇/水(1:9)超声浸提对蜈蚣草根和叶有最高的浸提效率,分别为60.2%和82.5%。样品加标回收率和相对标准偏差分别在92.7%～108.4%和2.05%～10.49%范围内。     

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.