38CrMoAl与多种涂层材料的结合性能分析

利用ANSYS workbench软件对涂层与基体进行建模,采用有限元方法分析38CrMoAl基材与TiN、TiC、SiC和DLC涂层材料之间的结合力情况,研究了结合力随涂层不同及施加载荷不同的变化.结果表明:当TiN、TiC、SiC涂层与基体结合时,残余应力主要集中在涂层与基体的结合处,在涂层表面与基体内部的分布较为均匀,而DLC涂层由于具有较好的导热性,能够快速的将残余应力导向基体中;残余应力与扩散距离的关系在涂层表面处呈现非线性的变化,而在涂层界面和涂层整体则是随着应力扩散距离的增加,先急速减少再到基本保持不变.所以,采用适当的涂层制备工艺,对残余应力的改变与材料的使用性能会有很大的影响.     

基体温度对氮化钛涂层微观结构的影响

双辉离子渗金属(DGPSA)技术,在硬质合金基体表面上沉积氮化钛(TiN)涂层,通过x射线衍射(XRD)表征和显微硬度计测试,研究了基体温度对TiN涂层微观结构及其性能的影响．实验结果表明：所制备的TiN涂层均为面心立方结构,并且基体温度明显影响TiN涂层的织构系数、晶粒尺寸、晶格常数、残余应力、微观硬度和耐磨性能．当基体温度为650～780℃时,所沉积TiN涂层具有最小的晶粒尺寸、最高的显微硬度、最大的品格 常数和最好的耐磨性能．     

基于微晶刚玉砂轮的20 CrMnTi齿轮成型磨削表面完整性

为研究微晶刚玉砂轮成型磨削20CrMnTi齿轮的表面完整性,开展了20CrMnTi齿轮成型磨削试验,分析了砂轮线速度、轴向进给速度及径向进给量对齿面粗糙度、表层/次表层显微硬度、微观组织和残余应力的影响规律,探讨了由磨削引起的磨削烧伤、微观裂纹等损伤缺陷的形成机理,结果表明:径向进给量对表面粗糙度的影响最显著,砂轮线速度次之,轴向进给速度最不显著;磨削温度过高会导致磨削烧伤,淬火烧伤使得表面硬度提高5%~20%,回火烧伤则导致表面硬度不同程度地下降;表层组织从外至内分别为白层、暗层和基体组织,白层主要由致密的马氏体+碳化物+残余奥氏体组成;砂轮线速度和径向进给量的增大使得由磨削引起的残余拉应力增大,表面残余压应力下降并逐渐向拉应力转变,当表面最终残余拉应力大于材料的断裂强度时,表面产生微观裂纹.     

316L带极埋弧堆焊残余应力和微观组织的表征

在Q345R表面堆焊焊带309L和316L,其中309L为过渡层。依据标准对熔敷金属进行试验;对试样进行残余应力测定;使用电子背散射技术观察熔敷金属309L层、基体Q345R侧和熔合线附近的微观组织特征。结果表明：熔敷金属铁素体含量、化学成分、晶间腐蚀都满足标准要求;熔敷金属残余应力为压应力,从上表面到316L与309L界面残余应力逐步增大,从316L与309L界面到309L与Q345R界面残余应力逐渐减小,从309L与Q345R界面到基体残余应力逐渐增大。在熔合线附近出现晶粒细化的现象,在热影响区,距离熔合线越近,热输入越大,晶粒直径也越大;熔敷金属层,晶粒倾向于沿着垂直于熔合线的方向生长。     

等离子喷涂制备铁基非晶-纳米复合涂层

以一种多元素铁基非晶合金粉末(含C,si,B,Cr,W,Mo,Ni,Fe等)作为喷涂材料,用大气等离子喷涂在316L不锈钢基体上制备涂层.用X射线衍射仪检测涂层的晶型结构,扫描电镜观察涂层的形貌,透射电镜观察涂层的微观组织结构,显微硬度仪测量涂层的显微硬度,纳米压痕仪测量涂层的硬度及弹性模量,并用谢乐公式计算了晶粒尺寸.结果表明:所制备的涂层均匀致密,与基体结合良好;涂层含有非晶和纳米颗粒;这种非晶-纳米复合涂层具有很高的硬度和弹性模量.     

电弧离子镀制备Cr-O-N涂层及生长机理探讨

为了弄清O2和N2的流量变化和基体负偏压对涂层微观结构的影响,利用电弧离子镀技术制备了Cr-O-N涂层,对涂层样品进行了X射线衍射分析,扫描电镜和原子力显微镜观察,电子探针成分分析,结果表明Cr-O-N涂层含CrN和Cr2O3相,衍射峰的择优取向、涂层的表面粗糙度、相含量和化学成分与制备过程中的气体流量、基体负偏压等因素密切相关:随着氧流量的增加,涂层的表面粗糙度上升,涂层中氧元素含量和Cr2O3相含量增多;基体负偏压的升高有利于涂层沿CrN(220),Cr2O3(300)面择优生长和涂层的致密性提高.     

硬质合金TiN涂层的残余热应力数值分析

采用有限元方法分析了硬质合金氮化钛涂层的热残余应力,试样采用圆柱体状的轴对称几何模型和自由边界条件,分析了涂层厚度、基体参数和过渡层对残余热应力的影响.计算表明:TiN涂层中出现较大的拉应力(1 GPa以上),而硬质合金基体中出现较大的压应力(-0.8 GPa左右).涂层中的拉应力随硬质合金基体中钴的质量分数和涂层厚度的增加而明显减小,因此通过增加基体中的钴的质量分数和涂层厚度可以减小涂层中的拉应力.当采用TiC过渡层时,涂层应力可以减小25%,且采用TiCN梯度过渡层时效果更好.     

双层辉光离子渗金属技术沉积氮化钛薄膜的微观结构研究

采用双层辉光离子渗金属技术,在硬质合金基体表面上制备了氮化钛（TiN）薄膜,通过微观结构和显微硬度分析,研究了基体温度对TiN薄膜性能的影响.实验结果表明：所有TiN样品均具有面心立方结构,并且薄膜生长的择优取向、晶粒尺寸、晶面间距、晶格常数和微观硬度等都与基体温度密切相关.当基体温度为650～780℃时,TiN薄膜具有最小的晶粒尺寸（26.9 nm）和最大的显微硬度（2204 HV）.     

拉伸螺杆表面真空烧结镍基合金界面组织研究

文章利用真空粉末烧结法在螺杆表面上制备镍基合金涂层,研究了涂层的组织及性能,分析了涂层与钢基体界面形成的特点、涂层的微观硬度分布及耐磨性能。结果表明,所获涂层与基体之间形成了良好的冶金结合,且涂层结构致密,表面具有较高的硬度。     

真空烧结Cr/WC-Ni基合金涂层的组织结构及力学性能研究

以Cr12MoV模具钢为基体材料,将调配好的WC-Ni60、Cr/WC-Ni60基复合原料均匀涂敷于处理好的基体样品上,经真空烧结制备出复合硬质合金涂层.实验结果表明,涂层结构均匀、致密,Cr/WC-Ni60基涂层的表面硬度高于WC-Ni60基复合涂层.     

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