直接进样高效液相色谱-柱后衍生法检测水中草甘膦和氨甲基膦酸

本文介绍了直接进样高效液相色谱-柱后衍生法对水中草甘膦和氨甲基膦酸的检测方法。水样直接进样,经高效液相色谱分离后草甘膦和氨甲基膦酸被衍生成强荧光物质,以荧光检测器进行检测;本文还对该方法的准确性和精密度进行了试验,结果表明该法对饮用水中草甘膦和氨甲基膦酸的最低检测限分别为0.015mg/L、0.011mg/L,相对标准偏差（RSDs,n=5）分别为1.63%、0.75%,加标回收率分别为107.52%、109.62%。该方法快速、灵敏度高、精密度好,能够满足生活饮用水对草甘膦及氨甲基膦酸的检测要求。     

高效液相色谱法测定生活用纸中甲醛、乙二醛、戊二醛的迁移量

建立了高效液相色谱测定生活用纸中的甲醛、乙二醛、戊二醛含量的方法,优化了色谱分析的参数,考察了不同的衍生条件,包括检测波长的选择、流动相的选择、衍生反应酸的选择、衍生反应试剂的用量、衍生反应溶剂的用量、衍生反应时间对衍生产物的影响,并对衍生物的稳定性进行了考察。本方法中甲醛、乙二醛、戊二醛在5mg/L～25mg/L范围内线性相关系数均大于0.995,方法检出限分别为0.01135mg/dm²、0.02462mg/dm²、0.04841mg/dm²,高、中、低3个水平加标回收率在90.6%～99.0%之间,相对标准偏差范围为0.36%～2.88%,可满足生活用纸中甲醛、乙二醛、戊二醛检测要求。     

UPLC-MS-MS测定红茶中的茶黄素含量

建立了一种快速测定红茶中4种茶黄素(茶黄素、茶黄素-3-没食子酸酯、茶黄素-3'-没食了酸酯和茶黄素-3,3'-双没食了酸酯)的超高效液相色谱串联质谱的分析方法。样品用70%的甲醇水浴提取,采用Waters ACQUITY BEH C18色谱柱分离,串联四级杆质谱多反应离子监测,外标法定量;色谱系统流速为250μL/min,柱温为30℃,流动相为0.1%甲酸和乙腈,梯度洗脱。结果表明,4种茶黄素在检测范围内线性关系良好,相关系数大于0.995,平均回收率在91.95%~105.37%之间,RSD(n=5)在2.37%~4.03%;方法的检出限在13.2~19.1 ng/m L,方法的定量限在39.7~52.6 ng/m L。所测红茶茶黄素含量为3.32 mg/g、茶黄素-3-没食子酸酯含量为1.96 mg/g、茶黄素-3'-没食了酸酯含量为1.48 mg/g、茶黄素-3,3'-双没食了酸酯0.70 mg/g,茶黄素总量为0.75%。该检测方法能快速检测红茶中的茶黄素含量,能有效分析评价红茶的品质,合理控制红茶生产质量。     

RRLC-Q-TOF-MS法研究人参皂苷Rh1对映异构体在大鼠体内的药代动力学行为

建立了高分离快速液相色谱-四极杆-飞行时间质谱(RRLC-Q-TOF-MS)法同时分离人参皂苷Rh1对映异构体,并研究其在大鼠体内的药代动力学行为。实验采用Agilent SB C18色谱柱,流动相A为水-乙腈（90∶10,V∶V）溶液,流动相B为水-乙腈（10∶90,V∶V）溶液,两种流动相内均含15 mmol/L甲酸铵,流速0.3 mL/min,进样量5 μL,二元线性梯度洗脱分离,在电喷雾负离子模式下进行质谱检测。结果表明,20-(S)和20-(R)人参皂苷Rh1的定量线性范围分别为0.24~39.00 mg/L和0.035~7.80 mg/L,定量限分别为0.20和0.03 mg/L,方法的检测限（S/N=3）分别为0.10和0.02 mg/L。精确度与精密度结果显示：两者的日内精确度分别为89.54%~95.79%和88.76%~94.33%,相对偏差小于5%;日间精确度分别为88.16%~92.41%和88.49%~94.35%,相对偏差小于5%。低、中、高3个浓度的提取回收率均大于90%。该方法可用于分离测定20-(S)和20-(R)人参皂苷Rh1,从而进行人参皂苷Rh1对映异构体在大鼠体内的药代动力学研究。     

高效液相色谱法测定奶粉中羟脯氨酸含量

建立了柱前衍生化高效液相色谱法(HPLC)测定奶粉中羟脯氨酸含量的方法。以2,4-二硝基氟苯为衍生试剂,采用Elite AAK C18色谱柱(250mm×4.6mm i.d.,5μm);0.05mol/L乙酸钠,乙腈/水(50:50,V:V)为流动相梯度洗脱;流速1.2mL/min;检测波长360nm;柱温27℃。结果表明:羟脯氨酸标准品在0.04～10.00mg/L范围内线性相关系数为0.9999;方法检出限为30mg/kg(S/N=10);加标浓度为0.05,8.0mg/L的平行5次测试结果相对标准偏差分别为9.64%和0.36%;0.05,0.1,0.25,0.5,1.0,2.0,8.0mg/L 7个加标水平测试,加标回收率在95.94%～114.87%之间,加标线性曲线的线性相关系数为0.9998。该方法定量结果准确,满足奶粉中羟脯氨酸含量测定的要求,可以作为判断奶粉中是否违禁添加皮革水解蛋白的依据。     

超高效液相色谱-串联质谱法检测牛奶中双氯芬酸钠残留

建立了测定牛奶中双氯芬酸钠残留的超高效液相色谱-串联质谱法。试样经乙酸乙酯提取、正己烷去除脂类,采用C18反相色谱柱进行分离,乙腈-0.1%甲酸水(55+45)为流动相洗脱,电喷雾离子源正离子模式下多反应监测模式(MRM)检测,内标法定量。结果表明,双氯芬酸钠在0.05~5ng/mL浓度范围内线性良好,相关系数0.9996;该方法在牛奶中检测限(LOD,S/N=3)和定量限(LOQ,S/N=10)分别为0.02μg/kg和0.05μg/kg。3个浓度添加水平下,回收率97.6%~113.0%,日内变异系数0.5%~9.5%,日间变异系数1.8%~7.4%。方法快速、灵敏度高、重现性好,能快速准确测定牛奶中双氯芬酸钠残留。     

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。     

超高效液相色谱-串联质谱法检测猪肌肉组织中烯丙孕素残留

建立了测定猪肌肉组织中烯丙孕素残留的超高效液相色谱-串联质谱方法。试样经乙腈和乙酸乙酯提取,低温冷冻去除脂类。采用C18反相色谱柱进行分离,以乙腈-0.1%甲酸水为流动相梯度洗脱,电喷雾离子源正离子模式下多反应监测模式检测,基质匹配外标法定量。结果表明,烯丙孕素在1~50ng/mL浓度范围内线性良好,相关系数大于0.99;该方法在猪肌肉组织中检测限(S/N=3)和定量限(S/N=10)分别为0.3μg/kg和1.0μg/kg。加标回收率68.5%~87.9%,日内变异系数1.1%~6.0%,日间变异系数5.5%~10.7%。方法快速、准确、灵敏度高,能满足猪肌肉组织中烯丙孕素残留定性定量分析。     

凝胶渗透色谱-高效液相色谱法测定食用菌中呋喃丹农药残留

建立了凝胶渗透色谱净化高效液相色谱法检测食用菌类中呋喃丹农药残留量的方法。样品经乙腈提取,氮气吹干,环己烷-乙酸乙酯(1∶1,V/V)溶液溶解后,凝胶渗透色谱进行净化,C18反相高效液相色谱柱分离后,采用液相色谱荧光检测器进行测定,外标法定量。呋喃丹在0.2~5.0ng/mL质量浓度范围内呈良好线性关系,相关系数r大于0.999,测定低限为0.01mg/kg。对空白食用菌样品进行3个浓度水平0.5、1.0和2.0mg/kg的加标回收试验,呋喃丹的加标回收率为78.3%~97.6%,相对标准偏差(RSD)为3.26%~11.69%。本实验所建立的方法简单,灵敏度高,适用于食用菌样品中的呋喃丹农药残留的分析检测。     

分散固相萃取-高效液相色谱-质谱联用法测定大米中的呋喃丹残留

建立了分散固相萃取-液相色谱-电喷雾质谱联用方法定量检测大米中呋喃丹残留量.应用分散固相萃取方法进行前处理,即以乙二胺-N-丙基硅烷(PSA)为吸附剂,乙腈为萃取溶剂,实现样品快速制备;在Agilent Eclipse C18色谱柱上,以甲醇-0.1%乙酸水溶液(50/50,V/V)为流动相,采用选择离子监测模式,以m/z222为检测定量离子.呋喃丹保留时间在6.7min左右,线性范围为0.003mg/L～1mg/L,相关系数0.9998,添加浓度在0.012,0.12,1.2mg/kg时,大米中呋喃丹的平均添加回收率在85%～96%之间,相对标准偏差(RSD,n=5)小于15%,最低检测浓度为0.012mg/kg.该方法灵敏、准确、可靠,定量范围宽,耐用性强,可作为大米中呋喃丹残留的可靠检测方法.     

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...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

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.     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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.