纳米坡缕石改进水润滑轴承性能的研究

水润滑轴承的摩擦性能取决于橡胶轴瓦的润滑状态、硬度、动态粘弹性等.选取坡缕石(AT)纳米粉体,经硅烷偶联剂KH-550表面改性处理后,加入NBR制成AT/NBR橡胶轴瓦硫化胶试件与AT/NBR水润滑轴承试件.检测表明,AT/NBR橡胶轴瓦硫化胶试件的综合力学性能、硬度提高.动态力学分析仪DMA测得,NBR,AT/NBR橡胶轴瓦硫化胶试件0℃时的损耗因子大约相等,表明两者的湿滑能力基本不变.通过轴承摩擦磨损试验机,测出AT/NBR轴承试件的水润滑摩擦噪声、摩擦系数与磨损量降低.以上实验表明,AT/NBR轴承试件比NBR轴承试件的摩擦磨损等性能指标有所提高,并达到了美军标(船舶)MIL-DTL-17901C(SH)的规定.     

结构参数对水润滑橡胶合金轴承摩擦噪声的影响分析

为了研究水润滑橡胶合金轴承结构参数对其低速重载工况下摩擦噪声的影响,使用复模态分析方法建立了水润滑橡胶合金轴承系统仿真模型,采用专业仿真软件分析了不同摩擦系数及结构参数条件下摩擦噪声产生的概率,进而研究结构参数对摩擦噪声的影响,进行了平板型和圆弧型结构的水润滑橡胶合金轴承摩擦噪声的对比实验。研究结果表明,水润滑橡胶合金轴承的水槽半径大小、摩擦面形状以及摩擦副的摩擦系数对水润滑橡胶合金轴承的摩擦噪声有较大影响,而水槽的形状对轴承摩擦噪声的影响不大。对一定结构尺寸的水润滑橡胶合金轴承,水槽半径为4mm、平面型摩擦面的结构可以大大减少轴承出现摩擦噪声的可能性,相关实验结果与计算结果是吻合的。     

橡胶衬层硬度和厚度对水润滑轴承系统跳动量的影响

根据舰船推进装置对水润滑轴承系统的运行精度要求,通过建立水润滑橡胶轴承系统有限元接触模型,研究不同橡胶硬度、厚度对直槽和螺旋槽水润滑橡胶轴承系统跳动量的影响规律,提出水润滑轴承系统跳动量控制方法。研究结果表明,水润滑橡胶轴承系统跳动量随橡胶硬度增大而减小,随橡胶厚度增大而增大。当橡胶硬度在85~95Shore A时,轴承系统主轴跳动量较小。在保证沟槽尺寸的前提下,尽量设计成较薄的橡胶厚度。相比直槽结构,螺旋槽水润滑橡胶轴承系统跳动量更小。因此,科学合理地设计水润滑橡胶轴承橡胶衬层材料硬度和几何结构,能显著减小轴承系统的跳动量,提高运行精度。     

纳米MoS_2复合陶瓷层结构与性能

为提高铝合金的表面硬度并降低其在摩擦磨损过程中的摩擦系数,在电解液中添加二硫化钼纳米粒子,利用微弧氧化技术在ZL109铝合金表面制备出含有二硫化钼的复合陶瓷层,且其表现出良好的摩擦学性能.添加二硫化钼纳米粒子后,陶瓷层的表面粗糙度降低,但是硬度未发生明显改变.在摩擦磨损试验中,复合陶瓷层的摩擦系数相对普通陶瓷层有所降低.在二硫化钼纳米粒子质量浓度为5g/L时,陶瓷层的摩擦系数最低,相对普通陶瓷层下降47%.     

微米级二硫化钼作为添加剂的润滑油性能研究

将表面改性后的微米级二硫化钼添加至基础油中,利用MRS-10W型和M-2000型试验机,对所制备润滑油的摩擦学性能进行测定.结果表明,基础油中添加含量为1.5%的微米级二硫化钼后,润滑油的最大无卡咬载荷提高了15.5%,摩擦副之间的摩擦系数降低了33.1%,磨损量减少了43.5%.     

纳米微晶纤维素替代炭黑补强天然橡胶

采用纳米微晶纤维素(NCC)部分替代炭黑,制备了天然橡胶/纳米微晶纤维素/炭黑复合材料(NR/NCC/CB),研究了NCC对NR/CB复合材料性能的影响.结果表明,NCC提高了CB补强NR的扯断伸长率,并保持在500%以上,永久变形下降至30%以下,且NR/NCC/CB的拉伸强度和撕裂强度基本保持或略优于NR/CB,硬度则基本保持不变;NCC替代炭黑的量为5phr～20phr时,材料仍能保持良好的耐磨耗性能;NCC替代炭黑的量低于15phr时,材料的抗曲挠龟裂性能得到改善;NCC的加入还改善了材料的热空气老化性能,降低了材料的压缩疲劳生热,当NCC取代CB的量为10 phr时,复合材料的生热达到最低值13.0℃.     

柴油机活塞环-缸套典型材料摩擦磨损特性的研究

作者利用M200型摩擦磨损试验机、2001型轮廓仪、S-570型扫描电子显微镜Talyserf-S200型圆度仪等测试仪器,对中小型柴油机活塞环—缸套摩擦副常用的典型材料,进行交替配对组成九对摩擦副、在一定的速度及润滑条件下,以载荷及时间为参变量,考察它们的摩擦磨损特性。试验表明,合适的材料组配可以大大提高摩擦副的摩擦磨损性能,摩擦系数随载荷的变化而变化,在一定的载荷作用下,由于材料的塑性变形及石墨的润滑作用可使摩擦系数降低,摩擦系数与磨损量之间不能建立对应的函数关系。在合适的金相组织范围内较硬材质具有较高耐磨性,而活塞环材质硬度比缸套材质硬度较高时(本试验为40HB)摩擦副的磨损量最小。     

316L/45#钢在MoS2水基润滑液润滑下的摩擦磨损性能

通过316L不锈钢与45#钢在去离子水、二硫化钼水基润滑液、30#机械油3种工况下,分别改变其载荷进行滑动摩擦实验,比较其摩擦磨损性能并分析磨损机制。结果表明,载荷为250 N时,MoS2水基润滑液润滑工况下的摩擦系数比去离子水工况下降低67.3%,磨损量降低了83.5%;摩擦系数比30#机械油工况下增加12.5%,磨损量增加147.1%。     

45#钢在含有微米级二硫化钼的18#齿轮油中的摩擦磨损性能

通过45#钢在二硫化钼质量分数分别为0％,0．5％,1％,1．5％,2％的18#齿轮油润滑的5种工况下,进行不同载荷的滑动摩擦试验,比较其摩擦磨损性能并分析磨损机制。结果表明,载荷为300N时,二硫化钼质量分数为2％的18#齿轮油中45#钢磨损量比其在基础油工况下降低了43．5％,摩擦系数降低了33．1％。二硫化钼质量分数为2％时18#齿轮油的抗摩擦磨损性能最好。     

316L／45#钢在MoS2水基润滑液润滑下的摩擦磨损性能

通过316L不锈钢与45#钢在去离子水、二硫化钼水基润滑液、30#机械油3种工况下,分别改变其载荷进行滑动摩擦实验,比较其摩擦磨损性能并分析磨损机制。结果表明,载荷为250N时,MoS2水基润滑液润滑工况下的摩擦系数比去离子水工况下降低67．3％,磨损量降低了83．5％;摩擦系数比30#机械油工况下增加12．5％,磨损量增加147．1％。     

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.     

A computer generator for randomly layered structures

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

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.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

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.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with