聚吡咯修饰电极测定抗坏血酸的研究

对掺铁氰根聚吡咯电极的聚合、伏安行为、电催化效应及其在抗坏血酸测定中的应用进行了研究.该膜电极性能稳定,对抗坏血酸催化效果好,抗坏血酸浓度在5×10-6~6×10-3 mol/l范围内有很好的线性关系,用于测定果汁饮料中抗坏血酸获得满意结果.     

抗坏血酸在半胱氨酸自组装膜上的电化学行为及应用

半胱氨酸自组装修饰金修饰电极对抗坏血酸(Vc)具有很高的电催化氧化活性.在pH 2.0的0.1 mol/L缓冲溶液中,可得到一对准可逆的氧化还原峰.电极反应受扩散控制.氧化峰电流与抗坏血酸浓度在5.0×10-6～1.1×10-3 mol/L范围内成线性关系,检测限为1.0×10-6 mol/L.该分析方法应用于果汁中的抗坏血酸分析,结果令人满意.     

尾式吡啶基锰卟啉修饰电极的作用行为及应用

用电化学法研究了氯化5-[o-(4-(3-吡啶氧基)丁氧基)苯基]-10,15,20-三苯基锰(Ⅲ)卟啉修饰碳糊电极对抗坏血酸催化作用,以及不同pH下抗坏血酸(H_2A)和OH~-在[PyTPP Mn(Ⅲ)]CI的作用机制．pH2．2～5．2范围内,修饰电极对H_2A为一质子参与的电催化机理;随着pH的增加,OH~-和H_2A在电极上形成电催化氧化竞争,pH＞8．2时,由于OH~-逐渐占据了电活性中心,导致OH~-优先于H_2A在电极上电催化氧化,电化学和UV-Vis光谱证明OH~-与卟啉金属中心强烈作用,形成了氢氧根桥联锰卟啉二聚体结构,该修饰电极在酸性条件(pH4．0左右)用于H_2A的测定,在3．992×10~(-6)～4．602×10~(-4)M浓度范围内线性回归方程为Y=0．1449X+0．05894,R=0．9977(n=11);检测限可达7．067×10~(-7)M,并且电极在常温下保存1月,活性仍然稳定。     

酞菁铁-邻苯二甲酸二正辛酯修饰碳糊电极测定抗坏血酸的研究与应用

制备了酞菁铁-邻苯二甲酸二正辛酯修饰碳糊电极,发现该电极对抗坏血酸的电氧化具有催化作用.在最优化条件下,抗坏血酸的氧化峰电流与其浓度在1.0×10-6～3.4×10-4mol/L范围内成良好的线性关系,检测限为3.2×10-7mol/L.初步讨论了电催化机理.该电极已成功用于果汁和药品维生素C片中的抗坏血酸含量的测定.     

L-半胱氨酸自组装膜修饰电极对抗坏血酸的电催化氧化及其分析应用

研究了L-半胱氨酸自组装膜修饰电极(L-Cys/Au SANs)的制备方法和其电化学行为,发现该电极对抗坏血酸(AA)具有明显的电催化氧化作用,在pH 4.03的BR缓冲溶液中,AA在L-半胱氨酸自组装膜修饰电极上产生一灵敏的氧化峰,峰电流与AA浓度分别在8.0×10-7-8.0×10-6mol·L-1和4.0×10-5-4.0×10-4 mol·L-1范围内呈良好的线性关系,相关系数分别为0.997 0和0.996 7,检测限为1.6×10-7mol·L-1.该方法可用于AA的测定.     

对目视比色法测定碘酸铜溶度积的探讨

本文用目视比色法测定碘酸铜的溶度积常数,经过对试剂浓度、用量、操作方法等反复试验,测得K_(spcu(IO_3)_2)值能稳定在1.4× 10~(-7)—1.9×10~(-7)范围,比催化动力学测定值1.7×10~(-7)—3.6×10~(-7)更接近文献值1.4×10~(-7)。经大一无机实验课实践证明,效果良好。     

丙烯酸丁酯与罗布麻纤维的接枝共聚及产物物理性能的研究

本文以硝酸铈铵为引发剂,研究了丙烯酸丁酯与罗布麻纤维的接枝共聚反应规律及产物的物理性能。当铈离子浓度为6.5×10~(-3)～14×10~(-3)mol/L,单体浓度为0.7×10~(-1)～1.2×lO~(-1)mol/L,氢离子浓度为7×10~(-2)～1O×10~(-2)mol/L,40℃,反应3h,可以得到较高接枝率。接枝纤维断裂伸长比纯纤维有所提高,改善了柔顺性。     

多壁碳纳米管修饰电极对抗坏血酸的电催化作用

对抗坏血酸在多壁碳纳米管修饰电极上的电化学行为的研究表明,与裸玻碳电极相比,抗坏血酸在多壁碳纳米管修饰电极上具有更高的氧化峰电流和更低的氧化电位。实验优化了支持电解质、pH值、扫描速度等测定条件,此法测定抗坏血酸的线性范围为(1.0×10-5~5.0×10-4)mol.L-1,检测下限为8.0×10-7mol.L-1。此修饰电极制作简便,重现性和稳定性较好。     

抗坏血酸在α-环糊精掺杂纳米碳管涂层电极上的伏安行为

制备了α-环糊精掺杂纳米碳管涂层电极并应用于抗坏血酸的电催化氧化,结果表明,氧化电位降低了280 mV,电流响应明显增加.我们首次结合两种物质的特性纳米碳管的导电性及催化性能、α-环糊精的分子认知能力,对电极表面进行修饰.实验了抗坏血酸与α-环糊精超分子络合物的特性.差示脉冲技术用于定量分析抗坏血酸,线性范围为2.5×10-6～1.0×10-3mol*dm-3     

聚氯乙烯的GPC浓度效应的研究

以分子量为15.5×10~4、12.69×10~4、6.67×10~4(分子量分布宽度分别为1.83、1.59、1.38)的宽分布聚氯乙烯样品,进行了GPC测定(THF,25℃)。结果表明:GPC淋洗体积(V_(es))与浓度c呈线性函数关系。特性粘数[η]与dV_(es)/dc的关系是通过原点的直线。这与Song,M.S.提出的GPC淋洗体积与浓度依赖关系的新简化理论模型相符合。经宽分布校正后,利用GPC浓度效应可测定第二维利系数,其值分别为0.84×10~(-3)、1.00×10~(-3)、1.32×10~(-3)。     

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