电化学氧化后碳纤维的表面性质

研究了粘胶基碳纤维在不同电解质中经过电化学氧化后的润湿性能和BET比表面,并用XPS分析了电化学氧化前后碳纤维的表面基团。实验结果表明,电化学氧化可以明显增加碳纤维的润湿性能和比表面积。XPS的分析结果表明,经过不同电解质电化学氧化后碳纤维表面含氧基团的增加,尤其是强亲水性羧基的增加是碳纤维表面润湿性能提高的主要原因。     

炭黑的pH值与氧含量、表面酸性含氧基团含量的规律性

炭黑的表面性质对其应用有重要影响，本文研究了炭黑的元素组成、pH值、表面酸性含氧基团含量以及它们之间的相互关系。实验结果表明，炭黑的pH值取决于其氧含量，两者存在指数关系．详细讨论了测定条件对炭黑表面酸性含氧基团测定结果的影响。实验结果表明，中和反应时间为90min、碱溶液浓度为0．05mol／L时，实验的重复性较好，同时测定了炭黑表面羧基、酚羟基、内酯基等酸性含氧基团的含量，实验结果表明，炭黑的pH值与其表面酸性基团含量存在指数关联。     

射频冷等离子体处理碳纤维对其表面基团的影响与分析

作者采用经典化学分析法、x射线光电子能谱分析法,研究了碳纤维经氧冷等离子体处理前后表面酸性基团的变化。化学分析结果表明,碳纤维表面酸性基团增加了3.4倍;x射线光电子能谱分析结果表明,碳纤维表面O/C原子比提高1倍,冷等离子体处理条件如处理时间、气体流量、压力及输出功率等对碳纤维表面酸性基团的变化有重大的影响。根据分析结果,还探讨了氧冷等离子体氧化碳纤维表面的反应机理及其表面化学结构的变化规律。作者认为,碳纤维表面处理所产生的酸性基团,是提高碳纤维增强树脂复合材料的层间剪切强度的一个重要因素。     

复合氧化改性活性炭的物性及其对甲苯的吸附性能

利用4种化学试剂(HNO3溶液、NH3溶液、H2O2溶液与Fe(NO3)3溶液)对商业活性炭进行化学氧化改性。在含5%氧气和95%氮气的混合气体中,对改性活性炭进行热复合氧化改性。采用热重分析仪、孔隙分析仪、傅里叶红外分析(FTIR)与Boehm滴定对活性炭结构与表面基团进行测试,并利用改性活性炭对甲苯进行等温吸附实验。研究结果表明:强氧化剂预处理活性炭有助于热复合氧化改性中活性炭微孔孔容的增大;活性炭表面含氧基团由化学氧化改性和热复合氧化改性共同作用产生,热改性温度较低时,其主要由化学氧化改性生成,温度较高时,酸性基团主要来源于氧气与活性炭表面的氧化反应;酸性基团的存在能够促进活性炭吸附甲苯;控制合理的热复合氧化改性条件,既可以增加活性炭表面酸性基团,又可扩充微孔孔容,从而综合提升活性炭对甲苯的吸附能力。     

碳纤维的电化学表面改性及其表面结构演变

采用电化学氧化法对聚丙烯腈(PAN)基碳纤维进行表面改性,联用场发射扫描电子显微镜(FESEM)、拉曼光谱(Raman)和X射线光电子能谱(XPS),表征了碳纤维表面物理化学结构。结合力学性能分析,评价了碳酸氢铵、氯化铵和硫酸铵三种电解质的改性效果,解释了碳纤维表面薄弱层产生的原因,分析了电化学改性碳纤维表面的机理。结果表明,在电化学改性过程中,碳纤维表面活性氧含量呈现梯形变化趋势,最高增幅达87.8%,而活性氮含量则不断增加直到饱和,可达到2倍增幅;相对于羧基等含氧基团,碳纤维复合材料(CFRP)层间剪切强度(ILSS)对胺基等含氮官能团更加敏感;当电解质中存在二价阴离子时,有利于减小碳纤维抗张强度的损失,甚至使其得到提高。     

水热温度对改性活性炭制Pd/AC催化剂性能的影响

文章采用水热硝酸氧化法对活性炭表面基团进行处理,考察了水热温度对活性炭的孔结构、表面含氧基团的影响,对催化剂进行了一系列表征,并评价了Pd/AC催化剂催化甲酸分解的性能。结果表明,随着水热温度的提高,活性炭上含氧基团先增加后减少,水热温度过高会破坏活性炭孔结构,使Pd粒子尺寸先减小后增大,同时催化剂活性先升高后降低。硝酸浓度为1.0mol/L,水热4h,水热温度为150℃时,催化活性最好;在甲酸浓度为0.01mol/L,90℃反应1h情况下,催化甲酸分解率达到92.2%。     

不同电化学条件下氧化后碳纤维表面基团的XPS分析

在不同的电流密度,电解质浓度和处理时间上对粘胶基碳纤维进行电化学氧化,然后用Ｘ－射线光电子能谱分析了氧化后碳纤维的表面基团,讨论了表面基团随着这些电化学条件的变化规律。     

超声波-双氧水联合氧化处理连续碳纤维表面的研究

使用超声波联合双氧水的方法对连续碳纤维（CCF）进行不同时间的表面氧化处理,再以聚酰胺（PA）为基体,热压制备连续碳纤维增强聚酰胺树脂复合材料。利用扫描电子显微镜（SEM）、X射线光电子能谱仪（XPS）和X-射线衍射仪（XRD）对联合氧化后的连续碳纤维表面进行分析表征,利用万能实验机对复合材料进行力学性能测试,结果表明：不同时间的超声波-双氧水联合氧化处理都能增加连续碳纤维表面的粗糙程度和活性官能团数量,其中联合氧化20 min后表面刻蚀效果比较显著,羟基、羰基等含氧官能团质量分数比未处理时提高79%和82%;连续碳纤维增强聚酰胺树脂复合材料的层间剪切强度比未经表面联合氧化处理提高36.8%。综合各项表征结果,20 min联合氧化后的碳纤维综合性能最优。     

氧化石墨片层中含氧官能团的探讨

采用Hummers法合成了氧化石墨(GO)产物,并通过XRD、IR、SEM和XPS等分析方法对产物进行表征分析.结果表明石墨被氧化为氧化石墨后仍具有层状结构,层间距比石墨大,层间含有大量的含氧功能性极性基团,包括羟基、羧基、醚基,未发现文献报道的环氧基团.     

Pt-羧基化CNTs／GC复合修饰电极的制备及对甲醇电催化氧化性能

运用循环伏安法制备Pt-羧基化CNTs／GC复合电极，研究了该电极对CH3OH的电催化氧化行为．结果表明，制得的复合电极对甲醇的氧化呈现了较高的电催化活性．Pt在羧基化碳纳米管上的高度分散和Pt与含氧基团的相互作用，是Pt-羧基化CNTs／GC复合电极对甲醇催化活性较高的原因．     

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.     

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     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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