脉冲电流聚合苯胺

采用脉冲电流和恒电流分别合成聚苯胺,通过循环伏安曲线和电镜扫描照片对它的电化学性质进行表征,脉冲电流合成聚苯胺的峰值电流比恒电流的高,其电化学活性更强.两种方法合成的膜结构不同,脉冲电流合成的聚苯胺是纳米纤维结构,恒电流合成的聚苯胺是颗粒结构.并且在硫酸、硝酸不同介质条件下的聚苯胺的扫描电镜图相似,均为纤维结构.     

稀土添加剂对电沉积磷酸钙涂层的影响

采用电化学沉积的方法在钛合金(Ti-6Al-4V)表面制备生物涂层.通过加入添加剂稀土硝酸镧和氧化钇制备了两种磷酸钙盐/稀土复合涂层.试验研究了稀土对涂层的微观形貌及涂层厚度的影响.结果表明:稀土的加入使涂层变得更为均匀致密.与单一涂层相比,稀土盐的添加有效的提高了涂层的厚度.XRD分析表明,稀土的加入并没有影响磷酸钙的生成.     

微弧氧化-电化学共沉积磷酸钙类涂层的研究

本项工作采用电沉积的方法在微孤氧化后的钛基体上制备了磷酸钙类涂层.室温条件下在300V恒压下阳极氧化1min,形成均匀孔洞的钛片,孔洞周围有较规则的突起,在此基础上进行电沉积不同时间获得磷酸钙类涂层.用扫描电子显微镜(SEM)、X射线衍射(XRD)等手段对涂层进行了表征,体外模拟后涂层表面形成了羟基磷灰石,锐钛矿型TiO2,金红石型TiO2.涂层的磨损试验结果表明,该涂层的摩擦磨损性能得到了极大的改善.     

沉积时间对真空离子镀TiC涂层微磨具表面性能的影响

采用真空电弧离子镀膜方法进行微磨具表面涂层制备实验研究,实验选择不同沉积时间做单因素实验进行涂层制备.分析了不同沉积时间的涂层物相组成,研究了不同沉积时间对涂层表面形貌的影响规律,探讨了其对摩擦系数和粗糙度的影响变化规律,以及对涂层厚度的影响规律,选出合理的沉积时间制备涂层微磨具.实验结果表明:钛镀层和金刚石发生界面反应,形成稳定的碳化钛层;随着沉积时间增加,摩擦系数不断增加,而粗糙度逐渐降低,涂层厚度逐渐增加.研究结果为涂层微磨具制备与提高微磨具的耐磨性和使用寿命提供了理论参考和实验依据.     

叠层模板电沉积中沉积均匀性的实验研究

为了改善叠层模板电沉积技术(LTE)中沉积层的均匀性,以减少辅助工序的工作量,采用直流电流、正脉冲电流和换向脉冲电流3组电流配置进行对比实验,对电流参数包括换向脉冲的脉宽、频率,工作时间、关断时间以及电流密度作了调整和优化.通过对宏观厚度和微观形貌的测量,发现:换向电流配置条件下,模板沉积层具有较好的均匀性, 换向脉冲电流的应用可以有效减少LTE工艺的加工难度和加工时间.文中还就换向电流对沉积层整平修饰的作用机理进行了理论分析,并采用优化的换向电流参数制备出了一批截面为20mm×20mm、厚度为4mm的铜质金属实体,证明了该技术的可行性.     

CNTs对MH/Ni电池正极电化学性能的影响

采用化学气相沉积法制备碳纳米管,将碳纳米管作为添加剂掺杂制备MH/Ni电池正极,研究了正极中添加不同含量在不同充放电制度下对电化学性能的影响. 结果表明,在30 mA/g恒电流放电条件下,添加了碳纳米管的模拟电池放电性能并没有得到改善,而且比没有添加的要差些;但在60 mA/g恒电流放电条件下,添加碳纳米管的作用比较明显,添加量为质量分数1%的碳纳米管电化学性能较好,在第40和80次循环时放电容量分别为272.2 mAh/g 和260.3 mAh/g,而且放电平台比较平稳.     

沉积工艺对聚苯胺涂层电学性能的影响及其抗磨损性能

神经电极表面涂层对电极性能有重要影响,其中沉积工艺是重要的影响参量.本文着重考察涂层沉积工艺对其电学性能的影响,并对最佳沉积工艺所得涂层的抗磨损性能进行研究.具体而言,在控制沉积过程中电极通过电荷量相当的前提下,比较3种聚苯胺电化学沉积方法的优劣.结果显示:相比裸电极,循环伏安沉积电极阻抗降低了29.7%,CV面积增加了4.05倍;恒电流沉积电极阻抗降低了39.8%,CV面积增加了5.4倍;恒电位沉积电极阻抗降低了4.3%,CV面积增加了4.9倍,恒电流法效果最佳.较低的阻抗及较大的CV面积意味着较好的电学性能.在此标准下,恒电流沉积时间为600～700 s时,沉积效果较好.为考察聚苯胺涂层磨损后对电极性能改善效果的影响,设计了一种模拟体内磨损装置进行相关试验.结果显示:磨损过程中涂层的电学性能改善效果逐渐下降,经4 h磨损后,修饰电极的阻抗值甚至高于裸电极阻抗.因此,在对导电涂层的评估中,其抗磨损性能应引起重视.     

换向电流在叠层模板电沉积中的研究和应用

摘 要： 叠层模板电沉积是一种通过逐层模板沉积以成形复杂金属结构的新型制造技术。通过前期实验,认为该技术的关键在于保证单层表面的沉积质量以确保沉积逐层顺利进行,而调整电流参数配置可以有效地改善表面的沉积质量。本文分析了双脉冲电流对铸层的整平修饰作用,认为其中的负向脉冲电流可以腐蚀削减铸层表面微观突起的生长高度。试验中采用3种电流配置进行对比实验,配置分别为：纯直流配置、正脉冲电流和双脉冲电流。实验对电流参数包括正负脉冲的脉宽、频率,工作时间、关断时间以及电流密度作了调整和优化。实验结果验证了理论分析,通过宏观厚度测量和微观形貌,表明双脉冲电流配置条件下,模板电铸层的均匀性具有明显的改善。实验中制备出一批截面为20mm×20mm,厚度为4-7mm具有一定几何形状的铜质金属实体。     

NiTi形状记忆合金表面电化学沉积-碱处理制备HA生物活性涂层

采用电化学沉积-碱处理,在低温条件下从含钙和磷离子的电解水溶液中在NiTi形状记忆合金表面沉积了磷酸钙涂层,经碱处理获得羟基磷灰石(HA)涂层.对涂层的组织形貌和相组成进行了分析,并研究了实验工艺对涂层结构的影响.研究结果表明,电化学沉积涂层CaHPO4*2H2O经碱处理后转变为羟基磷灰石;对试样进行表面处理,同时在电解液中加入有机溶剂得到的涂层更均匀、更致密.     

MnO_2/碳纳米管膜柔性复合材料的制备及其电容性能

为了获得比电容大、工作稳定性高的柔性超级电容器,在碳纳米管膜上利用恒电流沉积法在不同沉积时间和沉积电流密度下沉积MnO_2,制备出了MnO_2/碳纳米管膜柔性超级电容器电极材料.分别利用扫描电镜和X线衍射对所得电极材料的形貌和结构进行表征,并通过恒电流充放电测试和交流阻抗谱研究了复合材料的电容性能.结果表明:复合材料的电容性能可以通过调节MnO_2的沉积电流密度和沉积时间来控制;沉积电流密度为1 A/g、沉积时间为20 min条件下制备所得MnO_2/碳纳米管膜复合材料的比电容可达356 F/g,是纯碳纳米管膜比电容的7.5倍.此外,MnO_2/碳纳米管膜复合材料的比电容经200次充放电循环后维持在初始值的96.6%,显示出良好的循环稳定性,在高性能柔性超级电容器应用方面展现了一定的前景.     

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.     

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