超高效液相色谱-串联质谱测定食品中碱性桃红T染料

建立了用超高效液相色谱-串联质谱检测食品中非法添加物碱性桃红T染料的方法.样品经80%碱化甲醇提取,在碱性条件下用聚酰胺固相萃取小柱富集、净化,并经酸化甲醇洗脱后通过超高效液相色谱-串联四极杆质谱仪检测.液相色谱条件:分离柱为Waters Acquity BEHC18柱(1.7μm,2.1 mm×100 mm);流动相为0.4%甲酸水溶液-纯甲醇;流速0.3 mL.min-1.碱性桃红T的检测限为0.3μg.kg-1,6种食品样品的回收率为83.9%~92.5%,相对标准偏差(RSD)为5.6%~8.3%(n=6).在16~800μg.kg-1浓度范围内呈良好的线性关系,线性回归系数r为0.996 6.     

固相萃取-高效液相色谱法测定枸杞子中吡虫啉残留量

建立固相萃取-高效液相色谱法测定枸杞子中吡虫啉残留量.样品用乙腈提取,中性氧化铝和活性炭固相萃取柱净化,分析时采用Inertsil(R) ODS-3(25cm×4.6 mm,5μm)色谱柱分离,以乙腈-水为流动相梯度洗脱,流速1.0 mL/min,检测波长为270 nm,柱温35 ℃.试验结果表明,在0.02～5.0 mg/L范围内,吡虫啉峰面积与浓度呈良好的线性关系(r=0.9999),枸杞子样品中吡虫啉能得到良好的分离,回收率及重复性良好.     

固相萃取联合液相色谱-三重四级杆质谱测定饮用水中的亚硝胺类物质

用椰壳活性炭小柱对水样中的亚硝胺进行固相萃取,以SB-C8柱为分离柱,不同体积比的甲酸和甲醇为流动相进行梯度洗脱,采用大气压化学电离源和多重反应检测模式,建立了固相萃取(SPE)技术联合液相色谱-三重四级杆质谱(LC-TQMS)测定饮用水中8种亚硝胺消毒副产物的方法.考察上样时间、洗脱液量、氮吹时间和pH对回收率的影响,并优化固相萃取过程.结果表明,固相萃取过程中,上样时间1.5h,洗脱用量13mL,氮吹时间75min和pH 8时可以获得较高的回收率,8种N-亚硝胺类化合物在1～100μg·L~(-1)范围内线性关系良好,相关系数均大于0.99,8种N-亚硝胺类化合物的加标回收率为67.05%～93.78%,相对标准偏差为3.08%～9.23%(n=6),方法的检出限和仪器检出限分别为0.55～3.12μg·L~(-1)和0.12～1.95μg·L~(-1).     

气相色谱-质谱法测定鱼肉中丁香酚的残留

研究建立一种鱼肉中丁香酚(eugenol)残留量的固相萃取-气相色谱-质谱检测方法.样品采用正己烷提取,硅胶柱净化,乙酸乙酯洗脱,气相色谱-质谱测定,内标法定量.丁香酚的响应值与其质量浓度在0.005~0.5 mg·L-1范围内的线性关系良好,相关系数为0.999 8;10~200μg·kg-1添加浓度的日内和日间平均回收率为80.6%~93.2%,相对标准偏差为3.47%~8.47%;检出限为5μg·kg-1,最低定量限为10μg·kg-1.该方法适用于鱼肉中丁香酚残留的检测.     

固相萃取与高效液相色谱联用快速测定鲜奶中的三聚氰胺

采用固相萃取-高效液相色谱法测定鲜奶样品中的三聚氰胺.固相萃取柱为Strata-X-C,液相色谱柱Thermo BDS HYPERSIL C8(4.6 mm×250 mm,5μm);流动相为乙腈:0.01 mol/L辛烷磺酸钠-柠檬酸缓冲溶液(10:90,V:V),检测波长为 238 nm.三聚氰胺峰的保留时间为 8.25 min.三聚氰胺在 1.0～50μg/mL 范围内具有良好的线性关系(R=0.997),在添加量为30,60,90 mg/kg 时,三聚氰胺标准加入回收率为90.40%～91.10%,RSD为1.14%～1.88%.方法检出限为0.1 mg/kg.     

顶空固相微萃取-气相色谱法测定洗涤制品中二噁烷

本文采用顶空-固相微萃取-毛细管气相色谱联用技术测定了洗涤制品中二噁烷量。使用自制萃取头(苯-丙共聚物与PEG-20复合)。顶空平衡温度为80℃,萃取时间为40min。使用石英毛细管柱:28m×0.32mm×0.4μmi.d.内壁涂有SE-30固定液。外标法定量,二噁烷测定结果的相对标准偏差(RSD)为9.33%;在0.35μg/g-160μg/g范围,色谱峰面积与质量浓度之间呈良好线性关系,线性相关系数(R)为0.9998;回收率为98.7%～102%。     

磁固相萃取与高效液相色谱法联用测定蜂蜜中的苯酚残留量

建立了一种磁固相萃取和高效液相色谱相结合测定蜂蜜中苯酚含量的新方法.制备了磁性氧化石墨烯复合材料,作为磁固相萃取吸附剂,通过红外光谱对其进行表征,并优化了影响磁固相萃取效率的一些主要因素,包括吸附剂用量、萃取时间和洗脱时间、样品pH值和样品体积、洗脱剂种类和用量等.在最佳条件下,该方法的线性范围为0.05μg·L~(-1)～125μg·L~(-1),线性相关系数(R~2)为0.998 6,检出限为0.02μg·L~(-1)(S/N=3),回收率为87.3%～92.0%,相对标准偏差(RSD)为3.1%(c=0.1μg·L~(-1),n=7).结果表明,该方法成功地应用于测定蜂蜜样品中的苯酚含量.     

液相色谱-串联质谱法同时快速测定婴幼儿谷物食品中3种莨菪烷生物碱

采用固相萃取净化去除样品中蛋白类物质的干扰,建立婴幼儿谷物食品中3种莨菪烷生物碱的液相色谱-串联质谱检测方法.样品经体积分数为80％(v/v)乙腈水溶液提取后,经Oasis PRiME HLB SPE固相萃取柱净化.净化后的样品采用Agilent Poroshell 120 EC-C18柱(2.7μm,3.0 mm×75 mm)分离,以0.1％(v/v)甲酸乙腈溶液和0.1％(v/v)甲酸水溶液为流动相,梯度洗脱,多反应监测正离子模式扫描,采用基质溶液外标法定量.3种莨菪烷生物碱在1.0～50.0μg·L-1浓度范围内线性关系良好(R2﹥0.999),方法的检出限均为0.5μg·kg-1;回收率为86.8％ ～103.3％,相对标准偏差为5.2％ ～8.9％.该方法前处理操作简便,灵敏度和准确度高,可实现婴幼儿谷物食品中3种莨菪烷生物碱的同时快速测定.     

高效液相色谱法测定启脾丸中橙皮苷的含量

目的:建立启脾丸中橙皮苷含量的HPLC测定方法.方法:色谱柱为ZORBAX Eclipse XDB-C18(4.6 mm×150 mm,5μm),流动相为0.2 mol.L-1醋酸铵-冰醋酸-甲醇(57.24∶2.76∶40),柱温23℃,流速为0.8 mL.min-1,检测波长为285 nm,进样量为5μL,外标峰面积法定量.结果:橙皮苷保留时间为5.6 min,进样量在0.04μg～0.36μg范围内线性关系良好,线性回归方程为Y=429.23X-206.79,r=0.9998,平均回收率为95.878%,RSD=1.963%.结论:该法快速准确、重现性好、结果满意,可用于该药物的质量控制.     

高效液相色谱法分析红色毛癣菌麦角甾醇的含量

采用反相高效液相色谱法,建立了测定红色毛癣菌中麦角甾醇含量的方法.样品经过皂化、提取后定量测定.用Waters symmetry shieldTM RP C18色谱柱(4.6mm×150mm,5μm),流动相为100 %甲醇,流速为1.0 mL/min,检测波长为282 nm,保留时间定性,外标法定量.麦角甾醇的保留时间为8.9 min.麦角甾醇在0.93～29.75 mg/L浓度范围内,峰面积与浓度呈线性关系,相关系数分别为0.9998.添加回收率实验表明,麦角甾醇的平均添加回收率为94.8%～96.3%;相对标准偏差为1.8%～3.3%;麦角甾醇的最低检出浓度为0.008 mg/L.本方法准确、简便、重现性好,可用于真菌中麦角甾醇的含量测定.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme