维多利亚蓝B荧光熄灭法测定痕量亚硝酸根

研究了在稀盐酸介质中维多利亚蓝B与亚硝酸根发生的亚硝化反应 ,基于维多利亚蓝B的荧光强度随亚硝酸根的加入量增加而明显降低的现象 ,建立了测定亚硝酸根的荧光熄灭法。该方法的测定范围为 0 .0 15～ 0 .5 0 0 μg·mL-1方法的检出限为 0 .0 0 5 μg·mL-1。方法操作简便、反应迅速、灵敏度高 ,以用于环境水样中痕量亚硝酸根的测定结果令人满意     

催化动力学光度法测定痕量亚硝酸根

研究在稀盐酸介质中,亚硝酸根对溴酸钾氧化罗丹明B褪色的催化反应,建立测定痕量亚硝酸根的催化反应光度法.该方法测定亚硝酸根的最大吸收波长540nm,表观摩尔吸光系数为2.9×105L·mol-1·cm-1.方法检出限为8.27×10-10g·mL-1在0～6.5μg/25mL范围内符合比耳定律,用于水果、蔬菜、肉制品、罐头样品中痕量亚硝酸根的测定,结果满意.     

溴酸钾氧化尼罗蓝催化光度法测定痕量亚硝酸根

基于在室温和酸性介质中,亚硝酸根对溴酸钾氧化尼罗蓝褪色反应的催化作用,建立了测定痕量亚硝酸根的催化光度新方法。测定亚硝酸根的线性范围为80～5000 ng·mL~(-1),检出限为51ng·mL~(-1)。用于水及食品中痕量亚硝酸根的测定。     

钒(Ⅴ)催化偶氮胂(Ⅲ)褪色反应特性的研究

研究了在磷酸介质中,钒(Ⅴ)对KIO4氧化偶氮胂(Ⅲ)褪色反应的催化作用及柠檬酸的活化作用,测定了体系的动力学性质,确定了反应的最佳条件,建立了测定痕量钒的新方法.实验表明,无柠檬酸时体系为准一级反应,表观速率常量为3.7×10-4s-1,表观活化能为99.4kJ·mol-1,钒的量在0～9.0×10-5g·L-1范围内与log(A0/A)呈线性关系,检出限为1.3×10-7g·L-1.有柠檬酸时为准零级反应,表观速率常量为1.6×10-3s-1,表观活化能为82.9kJ·mol-1,钒的量在0～5.0×10-5g·L-1范围内与ΔA呈线性关系,检出限为7.8×10-8g·L-1.本法简单快速,灵敏度较高,用于钢样中痕量钒的测定,结果较满意.     

间苯二酚偶联反应测定痕量亚硝酸根的光度法研究

研究了对氨基苯磺酸与亚硝酸根在盐酸介质中重氮化,然后在氨性缓冲溶液中与间苯二酚偶联成偶氮染料的反应.偶联产物的最大吸收波长在430nm.据此建立了一个简单、快捷、选择性较好的测定痕量亚硝酸根的可见光分光光度法.其表观摩尔吸光系数为3.6×104L·mol-1·cm-1,测定的线性范围为O～2.0 mg/L.用于水和蔬菜样品中痕量亚硝酸根的测定,结果满意.     

β-萘酚重氮偶联反应分光光度法测定痕量亚硝酸盐

研究了对氨基苯磺酸与亚硝酸根在盐酸介质中重氮化,然后在氨性溶液中与β-萘酚偶联成偶氮染料的反应.偶联产物的最大吸收波长在485nm.据此建立了一个简单、快捷、选择性较好的测定痕量亚硝酸根的可见分光光度法.该法的表观摩尔吸光系数为2.3×104L·mol-1·cm-1,测定的线性范围为0～2.8mg/L,用于水和蔬菜样品中亚硝酸根的测定,结果令人满意.     

β-萘酚重氮偶联反应分光光度法测定痕量亚硝酸盐

研究了对氨基苯磺酸与亚硝酸根在盐酸介质中重氮化 ,然后在氨性溶液中与 β -萘酚偶联成偶氮染料的反应 偶联产物的最大吸收波长在 485nm .据此建立了一个简单、快捷、选择性较好的测定痕量亚硝酸根的可见分光光度法 该法的表观摩尔吸光系数为 2 .3× 1 0 4 L·mol- 1·cm- 1,测定的线性范围为 0～ 2 .8mg L ,用于水和蔬菜样品中亚硝酸根的测定 ,结果令人满意     

间苯二酚偶联反应测定痕量亚硝酸根的光度法研究

研究了对氨基苯磺酸与亚硝酸根在盐酸介质中重氮化,然后在氨性缓冲溶液中与间苯二酚偶联成偶氮染料的反应。偶联产物的最大吸收波长在430nm,据此建立了一个简单、快捷、选择性较好的测定痕量亚硝酸根的可见光分光光度法,其表观摩尔吸光系数为3.6×10~4L·mol~(-1)·cm~(-1),测定的线性范围为0～2.0mg/L,用于水和蔬菜样品中痕量亚硝酸根的测定,结果满意。     

催化动力学光度法测定痕量铁的研究

研究在稀硫酸介质中,Fe(Ⅲ)催化过氧化氢氧化亚甲蓝褪色反应的适宜条件与动力学性质,建立了催化动力学光度法测定痕量铁的新方法.用固定时间法在645nm处监测催化反应,线性范围为0.044～40.0μg·L-1,检出限0.037μg·L-1,反应的表观速率常量为1.13×10-3s-1,表观活化能为93.3kJ·mol-1.本方法应用于农产品和蒙药样品中痕量铁的测定,相对标准偏差1.3%～4.0%,结果较为满意.     

阻抑动力学光度法测定痕量亚硝酸根的研究

实验发现,在一定条件下,亚硝酸根对Mn（Ⅱ）催化KIO4氧化溴甲酚绿褪色反应有显著的阻抑作用,这是一个新的指示反应。研究了该指示反应的动力学条件,给出了一种方便、灵敏地测定痕量亚硝酸根的新方法,该法测定亚硝酸根的线性范围是0．04μg·mL^-1～0.4×10μg·mL^-1,检测限为7．5×10^-3μg·mL^-1;除Ⅰ^-外20多种共存离子不干扰亚硝酸根的Ⅰ测量,Ⅰ的干扰可通过加入数滴0．2％的HgCl2的方法予以消除,方法应用于水和蔬菜中亚硝酸根的测定,结果令人满意。     

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.     

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of