聚氨基丙酸化学修饰电极的制备及其对抗坏血酸的电催化氧化研究

采用电化学聚合法研制了聚氨基丙酸修饰玻碳电极,该电极对抗坏血酸（AA）有良好的电催化氧化作用,AA在修饰电极上的氧化电位较空白裸电极负移450mV。在实验条件下,以线扫伏安法研究了修饰电极测定AA的线性范围为2×10-3～1×10-2mol／L。该电极具有较好的稳定性和重现性。     

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.     

卟啉修饰电极的制备及金属离子的电位溶出行为

目的 :将修饰电极应用于电位溶出分析 .方法 :采用化学吸附法制备出meso -四 (对 -乙基苯基 )卟啉和meso -四 (对 -甲氧基苯基 )卟啉修饰玻碳电极 .研究Zn(Ⅱ ) ,Cu(Ⅱ ) ,Cd(Ⅱ )和Pb(Ⅱ )金属离子在该电极上的电位溶出行为 ,并与预镀汞膜玻碳电极、玻碳电极的电位溶出行为进行了比较 .结果 :溶出时间 (τ)与金属离子浓度均有良好的线性关系 ,最适宜分析的浓度范围是Zn(Ⅱ ) :1× 10 - 7～ 5× 10 - 5mol/L ;Cd(Ⅱ )和Pb(Ⅱ ) :6× 10 - 7～ 5× 10 - 5mol/L ;Cu(Ⅱ ) :5× 10 - 8～2× 10 - 5mol/L .微分电位溶出分析时灵敏度提高一个数量级 ,相对标准偏差为 0 .90 %～ 2 .3% (n=15) .结论 :使用卟啉修饰电极进行电位溶出分析可获得好的重现性和满意的灵敏度     

杯芳烃的主客体化学传感器研究——对苯二酚的测定

选用 C-十一烷基间苯二酚杯 ( 4)芳烃作为主体分子 ,将其修饰在玻碳电极上 ,制成了一种主客体化学传感器 ,对溶液中的客体分子——对苯二酚进行了测定 .该电极具有良好的选择性 ,对 5 .0× 10 - 5 ～ 1.5× 10 - 3m ol/ L 的对苯二酚具有很好的线性响应 ,检测下限为 2 .5× 10 - 5 m ol/ L.同时 ,对修饰前后玻碳电极的表面状态进行了研究     

多巴胺在纳米金修饰微玻碳电极上的电化学行为研究

用电沉积的方式制备了纳米金修饰微玻碳电极 ,该修饰电极能分开多巴胺和抗坏血酸的氧化峰 .研究了溶液pH值、磷酸缓冲溶液浓度对多巴胺电化学行为的影响 .多巴胺氧化峰电流值与其浓度在 5× 10 - 6～ 1× 10 - 4mol/L范围内成线性关系 .     

伏安法测定抗坏血酸的应用研究

采用电聚合方法制备了依来铬黑T修饰玻碳电极,该修饰电极对抗坏血酸(AA)具有较好的催化氧化作用。在优化的实验条件下,AA的氧化电位大大降低,氧化峰电流显著增大,AA浓度在1.0×10-5～2.0×10-3 mol.L-1范围内与氧化峰电流成良好的线性关系。该电极制备简单,响应快,使用方便,用于AA的样品检测,效果良好。     

抗坏血酸在纳米金/石墨烯复合物修饰电极上的电化学行为研究

根据Hummers方法制备了石墨烯(GR),通过在石墨烯修饰玻碳电极(GR/GCE)表面电沉积纳米金粒子(Au NPs)制备了纳米金/石墨烯复合物修饰电极(Au NPs/GR/GCE),采用扫描电镜表征了电极形貌;并用循环伏安法研究了抗坏血酸(AA)在此修饰电极上的电化学行为,在p H=4.0的磷酸氢二钠-柠檬酸缓冲溶液中,AA在复合物修饰电极上产生一灵敏的氧化峰,氧化峰电流显著高于裸玻碳电极(GCE)和石墨烯修饰玻碳电极(GR/GCE);在优化实验条件下,建立了循环伏安法测定AA的方法,氧化峰电流与AA的浓度在7⁵00μmol/L和1500μmol/L和1³0 mmol/L范围内呈良好的线性,检出限为5μmol/L(信噪比=3);用该方法测定维生素C片中AA的含量,回收率在97.69%30 mmol/L范围内呈良好的线性,检出限为5μmol/L(信噪比=3);用该方法测定维生素C片中AA的含量,回收率在97.69%¹03.5%之间.     

Nafion 修饰玻碳电极伏安法测定痕量氧氟沙星的研究

为了探讨氧氟沙星简易的测定方法 ,报道了用Nafion修饰玻碳 (GC)电极测定痕量氧氟沙星的伏安法 .线性扫描过程中 ,在 +1.2 7V处发现一灵敏氧化峰 ,利用该峰可进行氧氟沙星含量的测定 .通过优化测定条件 ,利用该修饰电极测定氧氟沙星的线性范围为 :1× 10 -6～ 3× 10 -5mol/L ,检测限为 1× 10 -8mol/L .用于实际样品溶液中痕量氧氟沙星的测定 ,平均回收率为 99.5 2 % .     

单壁碳纳米管化学修饰电极的制备及其测定鸟瞟呤的研究

报告了一种制备单壁碳纳米管化学修饰电极的方法,并研究了鸟嘌呤在此修饰电极上的电化学行为.鸟嘌呤在单壁碳纳米管修饰玻碳电极上出现一个灵敏的氧化峰,峰电流位于0.64V(vs.SCE).与裸玻碳电极相比,单壁碳纳米管修饰电极显著提高鸟嘌呤的氧化峰电流.优化了各项测定参数,建立了一种直接测定鸟嘌呤的电分析方法.氧化峰电流与鸟嘌呤的浓度在5×10～8-2 × 10-5mol/L之间有很好的线性关系,开路富集3min,检出限为2×10～8mol/L.该方法检测限低、分析速度快、重现性好、准确可靠.     

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