同时测定水样中邻苯二酚和对苯二酚的电分析方法

用循环伏安法研究了邻苯二酚（Catechol,CAT）和对苯二酚（Hydroquinone,HQ）在十六烷基溴化吡啶（Cetylpyrid Bromide,CPB）和十二烷基苯磺酸钠（Sodium Dodecyl Benzene Sulfonate,SDBS）水溶液中的电化学行为.在CPB水溶液中,CAT和HQ的氧化峰电位正移,还原峰电位负移,氧化还原峰电流增大;在SDBS水溶液中,CAT和HQ的氧化峰电位负移,还原峰电位正移,氧化还原峰电流减小.用循环伏安法和微分脉冲伏安法研究了CAT和HQ共存体系的伏安行为,当体系中无CPB存在时,CAT氧化峰与HQ氧化峰发生严重重叠;当体系中加入1.0×10^-3mol/L CPB时,CAT与HQ氧化峰电位相差100 mV,从而实现了CAT和HQ的选择性测定,以此提出了同时测定生活用自来水样中CAT和HQ含量的电分析方法.     

聚对苯二酚修饰电极的制备及其对抗坏血酸的催化氧化作用

采用电化学方法制备聚对苯二酚薄膜修饰玻碳电极（PHQ/GCE）,并用该电极对抗坏血酸（AA）进行测定.研究发现：在0.2 mol/L Na2HPO4-NaH2PO4（PBS,pH 7.0）缓冲溶液中,以0.1 mol/L KCl作支持电解质,PHQ/GCE对AA有明显的催化氧化作用.同时,应用线性扫描循环伏安法对AA进行定量分析,其氧化峰电流与AA浓度在5.0×10-6～1.0×10-1 mol/L范围内呈现良好的线性关系,检出限为1.0×10-7 mol/L.对此机理进行详细研究,结果表明聚对苯二酚修饰玻碳电极上带有的酚羟基与脱氢抗坏血酸自由基之间形成的氢键是电催化氧化的主要原因.     

多巴胺在FcA/Nafion/GCE上的电化学行为及其SWV测定应用

研究了多巴胺（Dopamine,DA）在二茂铁乙酸（Ferrocenyl Acetic Acid,FcA）和Nation聚合物薄膜修饰玻碳电极（FcA／Nation／GCE）上的电化学行为,测定了DA在该修饰电极上的动力学参数,并用方波伏安法（SWV）对DA在FcA／Nation／GCE上的测定应用进行了研究．结果表明,与GCE相比,DA在FcA／Nation／GCE上的峰电流增大约10倍,氧化峰电位负移60mV,表明FcA／Nation／GCE对DA有良好的电化学催化作用;同时测得DA在FcA／Nation／GCE上的电子转移系数口为0．44,反应速率常数k。为0．106cm／s,表观扩散系数D0为5．4×10^-6cm^2／s．用SwV方法测得DA浓度在1．0×10^-5～2．0×10^-3mol／L范围内氧化峰电流（Jpa）与其呈良好的线性关系,线性拟舍方程为Jpa（μA）=47．524＋16．508c（10mol／L）,相关系数R=0．9989,检出限为1．0×10^-6mol／L,相对标准偏差为0．9％～1．1％,回收率为97．5％～100．1％．该测定方法简单快捷,测定结果令人满意．     

硫代硫酸钠在10-甲基吩噻嗪修饰碳糊电极上的电催化氧化及电分析方法

运用循环伏安法（Cyclic Voltammetry,CV）研究了硫代硫酸钠（Sodium Thiosulfate,ST）在10-甲基吩噻嗪修饰碳糊电极（10-Methylphenothiazine,MPT/CPE）上的电催化氧化行为.结果表明,ST在裸碳糊电极（Carbon Paste Electrode,CPE）上的直接电化学氧化过程十分迟缓,但在MPT/CPE上于0.572 V处出现一不可逆氧化峰,氧化峰电流大幅度增大,表明MPT/CPE对ST电化学氧化有显著的催化作用.同时测定了ST在MPT/CPE上的电极过程动力学参数,即电荷传递系数α=0.62,电催化氧化反应速率常数k=（2.92±0.06）×102（mol/L）-1.s-1.用微分脉冲伏安法（Differtial Pulse Voltam-metry,DPV）测得ST催化氧化反应峰电流与其浓度在2.0×10-4-1.0×10-2mol/L范围内呈良好的线性关系,线性回归方程Ipa（μA）=16.458c（10-3mol/L）＋8.835,R=0.999 4,检测限为6.7×10-5mol/L.对市售ST注射剂含量进行了电化学定量测定,所得结果令人满意。     

高同型半胱氨酸的单扫描极谱法测定

研究了单扫描极谱法快速测定血清中高同型半胱氨酸（Hcy）的方法.在HAc-NH4Ac （pH 6.0） 底液中,Hcy在-0.52 V（vs.SCE）处产生一敏锐的还原波,在4.00×10^-7～5.90×10^-5 mol/L浓度范围内,一阶导数峰电流与其浓度呈线性关系,检出限为5.00×10^-8 mol/L,RSD为3.5%（n=8）,方法回收率为94.3%～106%.方法简便、快速.     

铜离子在聚L-谷氨酸修饰玻碳电极上的电化学行为研究

采用循环伏安法制备了聚L-谷氨酸修饰玻碳电极,研究了铜离子在该修饰电极上的电化学行为,并提出了一种新的用于检测铜离子的方法.在pH值为6.86的混合磷酸盐缓冲溶液中,铜离子的阳极氧化峰电流与其浓度在1×10-7~1×10-3mol L范围内呈较好的线性关系,相关系数为0.999 5,检出限为0.1 nmol L.实验结果表明,该修饰电极制作简便,重复性和稳定性良好,可望用于铜离子定量检测.     

流动注射化学发光测定人血清中双嘧达莫的含量

碱性条件下,双嘧达莫对luminol-K3Fe（CN）6-K4Fe（CN）6发光体系的有显著的增强作用.基于此建立了一种流动注射化学发光法测定片剂和人血清中双嘧达莫含量的方法.方法的线性范围是（9.0×10^-9～1.8×10^-8 mol/L）,1.8×10^-8～1.8×10^-6 mol/L,检出限为1.0×10^-9 mol/L （S/N=3）.相对标准偏差为0.8%（双嘧达莫1.0×10^-7 mol/L,n=10）.     

新橙皮苷二氢查尔酮的电化学行为研究

采用循环伏安法和线性扫描伏安法研究了新橙皮苷二氢查尔酮在玻碳电极上的电化学行为。在pH=4．8的醋酸／醋酸钠缓冲溶液中,新橙皮苷二氢查尔酮的循环伏安图上呈现出一对氧化还原峰,其电化学过程表现出良好的可逆性。实验结果表明,电化学过程中新橙皮苷二氢查尔酮的电子转移数n为2,参与反应的质子数也为2。新橙皮苷二氢查尔酮的还原峰峰电流与其浓度在2．8×10^-7mol·L^-1至3．1×10^-6mol·L^-1范围内呈现出良好的线性关系。对1．1×10^-6mol·L^-1新橙皮苷二氢查尔酮溶液连续6次测定的RSD为2．2％,检出限为1．1×10^-7mol·L^-1     

L-半胱氨酸修饰金电极的制备及应用研究

通过电化学方法制得L-半胱氨酸修饰金电极,以该修饰电极为工作电极,建立了一种灵敏的、选择性的测定痕量铜离子的新方法．用该电极在含铜离子的NaH2PO4-Na2HPO4缓冲液中搅拌富集,对不同浓度的铜离子进行电化学测定时仅仅是峰电流发生改变,且峰电流随铜离子浓度的增大而增大,在1×10^-9～1×10^-5mol／L之间出现良好的线性关系．其最低检测限可达10^-10mol／／L.     

电沉积咖啡酸玻碳修饰电极对抗坏血酸的催化氧化

在pH=7.0的磷酸缓冲溶液中采用电沉积技术将咖啡酸修饰于玻碳电极表面制备了一层稳定的薄膜,该修饰电极制备简单,稳定性良好.用循环伏安法研究了抗坏血酸在修饰电极上的电化学行为,其氧化峰电流与抗坏血酸的浓度和pH值有关,当pH值达到7.7时,抗坏血酸在修饰电极上的氧化峰电流最大,氧化峰电流与抗坏血酸浓度在4.0×10-5～2.0×10-2mol/L范围成良好的线性关系,检测限为1.0×10-5mol/L,方法简单、快速、准确,可应用于抗坏血酸药片的检测.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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