高效液相色谱法测定烟草中的淀粉含量

研究了用高效液相色谱法测定烟草中的淀粉含量，方法检测限为3．0mg／L，相对标准偏差为1．6-2．1％，标准回收率在95～105％之间。新方法用于几种烟草样品中淀粉含量测定，结果令人满意。     

纳米二氧化钛-重铬酸钾协同光催化氧化体系快速测定化学需氧量

以纳米TiO2-K2Cr2O7协同光催化氧化体系为基础,结合分光光度法建立了一种快速测定水样中化学需氧量（COD）的简便方法．本方法具有线性范围宽,抗氯离子干扰能力强等优点．在选定的最佳条件下,线性范围为0．0-150．0mg·L^-1,检测限为0．4mg·L^-1;当氯离子含量在1000．0mg·L^-1以内时,相对误差在±5．0％范围内．     

HPLC测定天麻素的含量和有关物质

目的建立测定天麻素原料药中天麻素的含量及有关物质的高效液相色谱法．方法采用Hypersil C18色谱柱,甲醇·0．01moL·L^-1磷酸二氢钠（8：92,磷酸调节pH至4．0±0．1）为流动相,检测波长为220nm,流速1．0mL·min^-1．结果天麻素在2．5～40．0ug·mL^-1范围内,峰面积与其浓度线性关系良好（r=0．9999）,高、中、低3种浓度的平均加样回收率为99．7％～100．3％RSD为0．44％～0．82％,有关物质的限量为1．0％．结论本法准确、简便、快速,适用于天麻素原料药的质量控制．     

新疆红景天中红景天苷含量的测定

用反相高效液相色谱法，流动相为甲醇-0．1mol／L磷酸二氢钠(15：85)，紫外检测波长为280nm，流速1．0mL／min，测定新疆产红景天中红景天苷含量，结果表明，红景天苷对照品在10～320μg/mL内线性关系良好，r=0．999。平均加样回收率为96．5％；RSD为3．4％。稳定性良好。该法简便，分离完全，结果可靠，适用于红景天苷的含量测定。     

用反相高效液相色谱法测定农药草甘膦含量的研究

建立了柱前衍生紫外检测的反相高效液相色谱法，并用其测定了草甘膦原药压制剂中草甘膦的含量．色谱条件为ODS色谱拄，流动相y（甲醇）：y（水）=2：98，其中水相含w=0．1％的磷酸，流速为0＋8mL／min，紫外检测波长为240nm，拄温为室温．实验表明，草甘膦的线性范围为0．008～0．040mg／mL，平均回收率为101％．该方法简便、灵敏、准确，可作为草甘膦农药质量控制的一种新方法．     

替米考星的高效液相分析

建立了替米考星的高效液相分析方法 .在流动相为水 乙腈 四氢呋喃 磷酸丁胺缓冲液 (体积比为 80 5∶110∶6 0∶2 5 ) ,流速为 1 0mL/min ,色谱柱为ODS柱 (4 6mm× 2 0 0mm ,5 μm)的条件下 ,其保留时间为 6 5min和7 5min(顺式 +反式 ) ,可实现快速分离 .检测波长为 2 80nm时 ,在 2 0～ 8 0 μg的范围内 ,样品量与峰面积呈现良好的线性关系 ,最低检测限为 1 7μg ,方法的回收率在 99%～ 10 1% ,相对标准偏差 (RSD)小于0 5 % .该方法简便、快速 ,稳定性好 ,适用于批量样品的测定     

HPLC法检测发酵液中的木糖和木糖醇

建立高效液相色谱检测发酵液中木糖和木糖醇含量的分析方法．色谱柱为ZORBAX碳水化合物，柱温30℃，流动相为乙腈：水=80：20（V／V），流速1．2mL／min，示差折光检测器检测．木糖和木糖醇在 0．5～40．0mg／mL范围内浓度与峰面积线性关系良好（R2分别为0．9931和0．9947），平均回收率分别为99．80％（n=5，RSD=1.35％）和99．62％（n=5，RSD=1．65％）．方法简便、快速、准确。     

高效液相色谱法对黑米中花色苷成分的测定

建立高效液相色谱(HPLC)检测黑米中花色苷类物质的方法.黑米粉经石油醚和乙酸乙酯去脂后,70％乙醇浸提、超声波处理、浓缩后,进行高效液相检测.该方法花色苷质量浓度在0.005 2～0.052 mg/mL内具有良好的线性关系(R2 =0.999 8),平均回收率为99.72％,RSD为0.91％,花色苷最低检测限为0.1 ng/mL.该方法操作简便快速,精密度和稳定性好,可用于从黑色稻米种质资源中筛选高花色苷含量的黑米品种.     

谷物中脱氧雪腐镰刀菌烯醇含量测定方法的比较

建立了测定谷物中脱氧雪腐镰刀菌烯醇（DON）含量的酶联免疫吸附测定法（ELISA）和高效液相色谱法（HPLC）,利用两种方法对谷物样品进行DON含量测定,并对结果进行了比较．结果表明,ELISA法的检测限为0．043μg/mL,玉米、小麦样品的平均回收率分别为96．8％和97．3％;RSD的平均值分别为8．8％和4．4％;HPLC法的检测限为0．1μg／mL,玉米、小麦样品的平均回收率均为92．7％,RSD的平均值分别为6．8％和3．1％．结果显示,ELISA法相对HPLC法快速简便、回收率高．     

离子色谱法测定矿泉水中F^-、Cl^-等阴离子

建立了矿泉水中F^-、Cl^-,NO3^-、SO4^2-四种阴离子的离子色谱测定方法．方法采用ICS-1000型离子色谱仪．Lonpac AS14A色谱柱,ASRS ULTRA Ⅱ抑制器,8．0mmol·L^-1碳酸钠-1．0mmol·L^-1碳酸氢钠混合液为淋洗液,流速为1．0mL·min^-1．方法的线性范围广、线性相关性好（r=0．9992—0．9999）,相对标准差（RSD）为0．28％～0．91％,平均加标回收率为98．97％-103．4％,最低检测限为0．0111-0．0522mg·L^-1．该法测定矿泉水中F^-、Cl^-、NO3^-、SO4^2-等阴离子,不需外加试剂对抑制器进行再生．具有操作简便、灵敏度高、准确、快速等优点．     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the