氮化工艺对球铁镀铁层组织结构及耐磨性影响的研究

研究了不同的氮化工艺参数对球墨铸铁镀铁层组织结构及耐磨性的影响．低温镀铁层特殊的组织结构，使得在很低的氮化温度下，镀层仍可完全氮化．镀层中网、条纹随氮化温度升高而粘连粗化．氮化工艺对耐磨性影响的显著性大小顺序为：氮化温度、ＮＨ_３流量、氮化时间．温度升高耐磨性下降；时间延长，耐磨性趋于一致．在试验条件下获得的最佳氮化工艺为：Ｔ＝４５０℃，ＮＨ_３流量为３０Ｎｌ／ｈ，τ＝１ｈ．经该工艺处理获得的镀铁氮化层的耐磨性较之未氮化镀层提高了１６０倍左右．     

氧化锌、氧化亚锡的复合化学镀铜

研究了氧化锌、氧化亚锡两种固体微粒复合化学镀铜的工艺条件。重点探讨了镀液温度、p H值、Zn O及 Sn O浓度对黑碳钢表面复合化学镀铜层耐磨性的影响。结果是 :对 Cu- Zn O镀层 ,当镀液温度为 6 5°C、p H值为 1 2 .5、Zn O含量为 1 0 g/ L时镀层质量最好 ;对 Cu- Sn O镀层 ,当镀液温度为 70°C、p H值为 1 2 .5、Sn O含量为 5g/ L时镀层质量最好。同时 ,本文对 Cu、Cu- Zn O及 Cu- Sn O三种不同镀层的抗氧化性、耐磨性、镀层与基体的结合力作了比较 ,发现三种镀层与基体材料的结合力很强 ,而以 Cu- Sn O镀层抗氧化性及耐磨性为最佳。     

不同加热温度下镀铁层组织和性能的初步研究

本文测定了不同加热温度下镀铁层宏观内应力、显微硬度以及晶粒度和微观应力随加热温度的变化，并观察镀铁层组织的变化．根据测定说明镀铁层宏观内应力随加热温度升高呈指数下降。３００℃以下随加热温度升高硬度略为上升是由于高拉应力镀铁层随加热温度升高应力消除，从而对硬度测定影响减小的缘故。     

铁基SiC复合镀层的制备与性能研究

为提高普通镀铁层的硬度和耐磨性,扩大其在工业生产中的应用范围,进行了铁基复合镀层的制备与性能研究.通过球磨法制备了Si C颗粒(粒径为100~200 nm),向镀铁液中添加Si C颗粒并采用电沉积的方式制备铁基Si C复合镀层.利用显微硬度仪、扫描电子显微镜(SEM)、能谱仪(EDS)、摩擦磨损试验机等对复合镀层的显微硬度、形貌结构、元素成分和摩擦学性能进行测试.结果表明:复合镀层的硬度与普通镀铁层相比显著提高,稳压电压为6 V时复合镀层的显微硬度最大;复合镀层表面微裂纹呈网状结构,截面微裂纹呈短条状结构;镀层中加入Si C颗粒可阻止裂纹的扩展,减小摩擦系数,提高镀层的耐磨性能.     

激光辐照镀铬钢合金化工艺与性能研究

用大功率CO_2 激光器对镀铬 30CrMnSi 钢表面连续搭接式辐照处理,达到了在高含铬量的合金层和镀层与基体界面间获得高含铬量熔渗层两种不同的冶金效果,并实现镀层与基体间冶金结合。对比研究辐照前后耐磨性、阳极极化特性以及盐雾条件下的腐蚀行为,结果表明:激光辐照后耐磨性提高近一倍;激光合金化层耐蚀性明显提高;而熔渗工艺条件的电化学特性与原镀层相当,但原镀层穴蚀和龟裂的倾向得到克服,结合强度得到提高。     

Al-Mn合金镀层的制备与性能

利用AlCl3＋LiAlH4＋MnCl2有机溶剂体系在低碳钢基体上进行了电镀Al-Mn合金的实验，并对不同电镀工艺下Al-Mn合金镀层的表面形貌、成分、结构、厚度、结合力和耐蚀性等进行了研究．实验结果表明，沉积出的Al-Mn合金镀层表面光滑并呈网状分布；镀层中的Mn含量（原子分数）在3％～8％间变化，其中Mn以Al-Mn过饱和固溶体形式存在，且按（200）面的结构进行生长．随电镀时间和电流密度的增加，Al-Mn合金镀层的厚度呈线性增大，但膜层与基体的结合力逐渐降低．Al-Mn合金镀层的耐蚀性随沉积电流密度的增加而减小，随电镀时间的延长呈先增大后减小的规律．Al-Mn合金镀层的沉积速率、结合力和耐蚀性均高于相同沉积条件下的纯铝镀层。Al-Mn合金镀层在AlCl3＋LiAlH4＋MnCl2有机溶剂体系中的最佳沉积工艺为电流密度0．15～0．50A／dm^2、电镀时间30～45min．     

化学镀高磷Ni-P镀层的摩擦磨损性能

制备了一种高磷化学镀镍层并研究其表面形貌;讨论了其在不同温度热处理后的摩擦磨损性能,且与45钢进行了对比.结果表明,Ni-P镀层的耐磨性明显优于45钢,且经500℃热处理后硬度最高,耐磨性最好,可作为耐磨性镀层.在此基础上对化学镀Ni-P镀层的摩擦磨损机理进行了初步探讨,认为200℃热处理后主要表现为粘着磨损,500℃热处理后表现为磨料磨损和粘着磨损共存.     

镍磷化学镀层对基体材料疲劳损伤过程的影响分析

在微观层面上分析了Ni-P化学镀层及晶化处理Ni-P化学镀,两种层对基体疲劳裂纹萌生过程的影响.微观观察表明,由于经晶化处理Ni-P化学镀的脆性显著提高,且与基体的结合力进一步加强,在镀层中更容易形成疲劳裂纹,并且裂纹更加容易向基体扩展,结果使试样的疲劳寿命大幅下降.     

非铁基材料化学镀镍基合金

采用化学镀的方法在钨振子、PVC表面沉积镍基合金。为获得钨振子与镀层同较强的结合力，通过采用不同预处理、热处理方法来完成。实验表明，用以双氧水为主的混合液预处理，Ni-P合金镀层结合力最佳；在保护性气氛中热处理，可大大增强镀层与基体结合力。PVC表面用氯化钯活化可得到导电性良好的镍基合金镀层。     

铁基零件无氰镀铜新工艺

对无氰碱性镀铜镀液成分及镀层性能研究,获得了一种可以在铁基元件上直接镀铜的电镀工艺;研究了各成分对镀层性能的影响,获得了最佳工艺配比.对该新型镀铜工艺在铁基上的镀铜效果、均镀能力、深镀能力和镀层结合力分别进行研究,结果表明该工艺所得镀层与基体结合力良好,镀液工艺简单,容易控制,电流效率高,可以用来作为铁基元件镀铜层的打底和加厚.     

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