鸡精中呈味核苷酸二钠的高效液相色谱法测定

建立了高效液相色谱法测定呈味核苷酸二钠(IMP和GMP)含量的方法.以四丁基磷酸铵和磷酸二氢钾配以一定比例的乙腈为流动相,采用高耐水系Waters RP 18色谱柱,通过色谱条件的优化,获得了定性定量重复性相对标准偏差<2%的标准品色谱图,其中,IMP标准曲线在60～600μg/mL范围内的线性相关系数为R=1.0000,GMP标准曲线在50～480μg/mL范围内的线性相关系数为R=0.999 9.测得某品牌的鸡精内IMP质量含量为0.54%,GMP质量含量为0.60%,两次测定结果的精密度GMP为0.73%,IMP为1.17%.     

一阶导数光谱法测定舒尔芬片中双氯芬酸钠和磷酸可待因的含量

本文采用一阶导数光谱法测定舒尔芬片中双氯芬酸钠和磷酸可待因的含量.实验结果表明,在190nm～360nm波长范围内,在247.8nm处,磷酸可待因为吸收谷,双氯芬酸钠的D值为零,而在261.8nm处,双氯芬酸钠为吸收峰,磷酸可待因的D值为零,且在247.8m和261.8nm波长下,二者的浓度均与各自的振幅具有良好的线性关系,其相关系数分别为0.9999和0.9999.该方法不经分离即可同时测定舒尔芬片中双氯芬酸钠和磷酸可待因的含量,且简便、准确,回收率分别为101.9%和101.7%.     

分光光度法测定竹叶提取物中总黄酮含量的改进

针对测定竹叶提取物中总黄酮含量的分光光度法，作出部分优化：以碱性显色体系显色，增加显色剂用量，分别使用芦丁和异荭草苷作为标准品，制作标准曲线，竹叶提取物中总黄酮测定结果存在差异。在浓度0～40 mg/L范围内，芦丁、异荭草苷标准曲线的相关系数(r²)分别为0.9999、0.9998,平均加标回收率为97.93%、99.65%,对应测出总黄酮含量分别为30.3%与26.3%,RSD为1.35%、0.7%(n=6)。与高效液相色谱法测定结果比较，实验结果表明用异荭草苷制作标准曲线优于芦丁。     

离子色谱法测定环境空气中氯化氢含量

用碳酸钠-碳酸氢钠吸收环境空气中氯化氢(HCl),离子色谱法测定吸收液中的氯离子含量,根据采气量计算空气中HCl含量.在最佳条件下本方法的线性范围为0.25-6.00μg /ml,检出限为0.02μg Clˉ/ml,工作曲线的回归方程为Y=-3.199 + 16.67 Cl-(μg /ml),r = 0.9992, 相对标准偏差≤2.62%,标准回收率9.44～98.6%.该方法灵敏度高,检出限低,结果准确,适用于环境空气中低含量HCl的测定.     

高效液相色谱法测定脑络通片中维生素B6的含量

采用高效液相色谱法(HPLC)测定脑络通片中维生素B6的含量.色谱柱为C18 柱(250 mm×4.6 mm,5 m),流动相:甲醇-0.01%三乙醇胺溶液(用磷酸调pH值至2.5)为1:99,检测波长291 nm.维生素B6含量测定的线性范围是10.6～95.4μg/ml,r=0.9998(n=6),回收率为99.28%,RSD=1.90%.本方法灵敏、简便、准确,可以用于脑络通片中维生素B6的含量测定.     

三磷酸胞苷二钠-乙基紫体系的显色反应及其分析应用

在pH6.3的BR缓冲体系中,乙基紫与三磷酸胞苷二钠作用,形成离子缔合物,其最大显色波长位于594 nm处,在最大显色波长处,三磷酸胞苷二钠的浓度与溶液的显色强度呈良好的线性关系,可用于三磷酸胞苷二钠的测定.在波长594 nm处,三磷酸胞苷二钠的浓度在0.13×10-6～5.0×10-6g/mL范围内符合比尔定律,相关系数R=0.999 5,摩尔吸光系数为1.8×104L/(mol.cm),检出限为0.038μg/mL.方法快速灵敏、操作简便,用于样品中三磷酸胞苷二钠的测定,结果满意.     

黑骨藤中总黄酮含量的测定

对采自不同产地、不同年份黑骨藤的总黄酮含量进行了测定.以芦丁为对照品,检测波长510 nm,绘制标准曲线,采用紫外分光光度法测定总黄酮的相对百分含量.芦丁对照品在2.065～103.250 mg.L-1范围内有良好的线性关系(r=0.999 90),平均回收率为98.03%,RSD值为1.40%.采用分光光度法测定黑骨藤的总黄酮含量操作简便、结果可靠,为评价黑骨藤的质量提供了依据.     

新疆阿克苏恰麻古多糖的提取及含量测定

文章研究恰麻古中多糖的含量.采用紫外-可见分光光度法测定恰麻古多糖的含量,以葡萄糖为对照品,以苯酚-浓硫酸为显色剂,在486nm处测定样品溶液的吸光度.标准曲线为A=8.445x+0.0381,r=0.9998,回收率为101.7%,RSD=2.0%,恰麻古多糖的含量为9.01%.本方法具有操作简单,灵敏度高,可作为恰麻古多糖的含量测定方法.     

微波消解-火焰原子吸收法连续测定三氯苯肼中的铬、铁含量

采用微波消解-火焰原子吸收法,利用金属离子混合标液进行标准曲线测定,实现了2,4,6-三氯苯肼中微量铬和铁的快速连续测定.结果表明:混合标准溶液中铬的标准曲线为:A=0.087+0.028C,相关系数r=0.999 4;铁回归方程为A=0.048 8+0.127 6C,相关系数r=0.998 1.用该法测得三氯苯肼试样中的铬、铁含量分别为3.170 mg/L、1.620 mg/L;相对标准偏差分别为1.02%和1.79%;平均加标回收率为101%和99%.     

分光光度法测定硝普钠注射液中硝普钠的含量

在碱性条件下, 在含有苯酚和盐酸羟胺的溶液中加入硝普钠, 有蓝色物质生成, 该物质在波长690 nm处有最大吸收. 由此建立了测定硝普钠注射液中硝普钠含量的新的分光 光度分析法. 该方法线性范围1.0×10^-5～8.0×10^-5 mol/L, 标 准溶液测定的相对标准偏差为0.57％（n=6）, 实际样品测定的回收率＞95%, 与标准方法 对照分析的相对误差为-1.2%～0.91% , 40倍的Cl^-, SO^2-₄ , HCO^－_３, Mg²⁺和Ca²⁺不干扰 测定.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

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