纳米LaF3在润滑油中的分散稳定性对其摩擦学性能的影响

用醇水法制备了表面修饰纳米LaF3,通过相转移将纳米LaF3从水相转移到油相(500SN基础油)得到纳米LaF3含量为10.2%(质量百分数)的液体添加剂。采用X-射线衍射仪(XRD)和透射电镜(TEM)分析了纳米LaF3的结构和形貌。用四球机考察了其摩擦学性能及用扫描电子显微镜(SEM)观察了摩斑表面形貌。结果表明:颗粒状纳米LaF3平均粒径为9~17 nm,液体添加剂中的纳米粒子在基础油中的分散稳定性和摩擦学性能大大高于用溶剂洗涤法制得的LaF3干粉粒子,纳米粒子在基础油中的分散稳定性对其摩擦学性能影响很大。     

新型锌锡复合润滑剂及其对钢损伤表面的润滑修复性能

为改善钢类机械零件磨损自修复性能,该文研制了含活化的锌、锡两种添加剂的新型磨损自修复润滑剂,并在改进的MS-800型摩擦磨损试验机上,考察了使用该润滑剂的钢-钢面接触摩擦副的磨损自修复行为及其摩擦学性能。用X射线能谱仪和扫描电子显微镜分析了钢试样表面的化学元素分布、形成的修复涂层厚度及其表面形貌。结果表明,研制的锌锡复合润滑剂对钢损伤表面具有良好的润滑修复和减摩抗磨性能,可在机械运转中在钢受损摩擦表面形成20μm厚的修复涂层。     

汽车发动机应用金属磨损自修复材料技术的研究

通过在汽车发动机的润滑系统中应用金属磨损自修复材料技术,研究自修复材料保护层的摩擦性能、显微硬度,在行车试验中研究自修复材料技术对发动机的动力性能、节油、尾气等综合性能指标,并在形成自修复材料保护层的性能下进行了无机油行驶的研究.实验证明自修复材料可对已磨损的零件表面进行不拆卸原位修复,自修复材料保护层具有超低的摩擦系数.     

修复-润滑双功能微胶囊/环氧树脂复合材料的摩擦学性能研究

以润滑剂（亚麻籽油、聚α烯烃或1-丁基-3-甲基咪唑六氟磷酸盐）和修复剂（邻苯二甲酸二丁酯）为芯材,脲醛树脂为壳材,采用原位聚合法合成了双芯材微胶囊,将微胶囊填充在环氧树脂中得到固体自润滑复合材料;使用扫描电子显微镜（SEM）、傅里叶变换红外光谱仪（FT-IR）、热重分析仪（TGA）对微胶囊进行了表征;使用摩擦磨损试验机、三维白光干涉仪、光学显微镜、扫描电子显微镜测试了微胶囊/环氧树脂复合材料的摩擦和修复性能。结果表明,微胶囊在整体上呈球形,结构完整,两种芯材均成功包覆;当加入质量分数为10%的微胶囊（芯材为亚麻籽油和邻苯二甲酸二丁酯）时,与环氧树脂相比,在摩擦试验测试1 200 s后自润滑复合材料的摩擦系数降低了约90%,在磨损试验测试2 h后其磨损体积减小约3个数量级（由10¹⁰ μm³减小到10⁷ μm³）;被划伤的复合材料经50℃加热1 h后,与加热前相比划痕变窄、变浅。以上结果表明,制备的双功能微胶囊/环氧树脂复合材料的耐摩擦磨损性能相对环氧树脂有所提高,同时具有良好的自修复特性,极大地提高了复合材料的综合使用性能。     

齿轮传动的磨损自修复

研制适用于钢/钢摩擦副的含软金属Sn,Zn粉体的自修复润滑剂,在摩擦磨损试验机上考察该润滑剂的修复性能和摩擦学性能,用ANSYS软件仿真计算齿轮传动的齿面接触应力.研究结果表明,研制的Sn-Zn修复润滑剂可在钢表面摩擦形成修复层,在不同载荷下有良好的减摩和抗磨性能.仿真计算结果显示,该修复润滑剂可使修复齿面的接触应力降低16.7%.     

抗氧剂对以α-磷酸锆作为固体润滑剂的锂基脂摩擦学性能影响

以α-ZrP为固体润滑剂,分别以2,6-二叔丁基对甲酚(BHT)和二苯胺(DPA)为抗氧剂,制备了锂基润滑脂。分别采用SRV高频线性往复摩擦磨损试验机和四球机摩擦磨损试验机考察了这两种抗氧剂对α-ZrP锂基脂摩擦磨损性能的影响,用3D白光干涉仪、扫描电镜(SEM)和能谱仪(EDS)观察并分析了磨痕表面形貌和主要元素。结果表明,当复配抗氧剂质量分数为1.0%时,α-ZrP锂基脂在保持减摩性能稳定的同时,抗磨性能得到明显提升,有效地延长了润滑脂寿命。     

超细添加剂润滑脂超声制备与润滑减磨分析

研究了超细化添加剂润滑脂的超声制备方法,统计分析了亚微米MoS2添加剂和纳米C添加剂在润滑脂中的分布规律,在摩擦试验机上测试了所制备润滑脂摩擦性能,探讨了添加剂对润滑脂润滑效果的影响.结果表明,添加剂的超细化使其在润滑脂中的分布更加均匀,颗粒更加细小,润滑脂的润滑效果更好.     

室温下简易合成LaF3纳米粒子

以十六烷基三甲基溴化铵(CTAB)作表面活性剂,室温下直接沉淀反应制备LaF3纳米粒子,并用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和荧光分光光度计进行了结构和光谱表征.结果表明,LaF3纳米粒子呈片状,直径40 nm左右,结晶性能良好.     

Fe3O4复合丁腈橡胶的力学和摩擦学性能

研究了填充纳米Fe3O4粒子对丁腈橡胶(NBR)力学性能、摩擦学性能的影响.结果表明:填充纳米Fe3O4粒子后丁腈橡胶的力学性能略有降低,但其表现了良好的抗磨、减摩性能,其中填充质量分数为12%时材料的摩擦学性能最优.随着填充质量分数的增加,材料的磨损形式由犁削和粘着磨损逐步转变为粘着、疲劳剥落.磁性纳米Fe3O4粒子有利于在摩擦表面形成自修复膜,从而起到抗磨、减摩的作用.     

石墨烯作为润滑油添加剂在高温工况下的摩擦学性能

为了探究石墨烯作为润滑油添加剂在高温工况下摩擦学性能和抗黏着性能,采用四球摩擦磨损试验机对添加石墨烯的基础油进行摩擦磨损实验。用XRD对石墨烯进行表征,用基础油和添加不同质量分数的石墨烯润滑油进行对比。结果表明:在润滑油中添加石墨烯能显著提高摩擦副在高温工况下的摩擦学性能和抗黏着性能。在质量分数为0. 03%时,其摩擦系数约降低22. 5%,磨斑直径约减少48. 9%,抗黏着时间约增加44. 9%。     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

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