小孔节流静压轴承的模糊可靠性设计

对小孔节流静压轴承进行模糊可靠性设计.在设计中利用"可靠度"这一协调性指标,从轴承的整体利益出发,建立了以轴承的刚度最高为目标函数的模糊可靠性设计模型,编制了相应的软件进行相关的计算.实例计算表明了此方法的正确性和可行性.在液体静压轴承的使用中大部分采用定压供油系统,都是以节流器作为该系统的压力补偿元件.由于节流器的结构形式不同,使轴承上对置的油腔所产生的压力差也不同,即轴承的承载能力和压力油膜的刚度不同.     

曲轴连杆轴颈静压轴承的设计与数值模拟

针对静压轴承在曲轴连杆主轴颈上的应用问题,设计了油腔位于连杆主轴颈上的特殊结构静压轴承和油路通道.为了保证油源压力和轴承直径的均衡,改进了静压轴承的设计方法,确定了油源压力,计算了主要参数,最后确定了满足刚度无穷大条件的κ-β0值.采用流体动力学仿真软件对所设计的静压轴承进行仿真分析,得到了轴承的压力等高线和速度矢量图...     

气体静压球面轴承设计理论及其应用

为解决地面模拟空中飞行控制装置的支承问题,试制了气体静压万向球轴承。首先借鉴已比较成熟的气体静压轴颈轴承和气体静压止推轴承的设计方法,根据拓扑理论和力系等效原理将球体转化为等效的圆柱体,对气体静压球轴承进行近似设计。最后应用该设计理论,成功加工出气体静压球面轴承。     

准气体动力循环Power MEMS气体静压轴承

为追求微细尺度条件下超高能量密度的目标,提出了Power MEMS准气体动力循环发动机的概念.鉴于Power MEMS准气体动力循环发动机能够自行提供高压气源的结构特征以及气体静压轴承在性能上的优点,提出了将气体静压轴承应用于该Power MEMS发动机的研究和Power MEMS准气体动力循环发动机中气体静压径向轴承和止推轴承的结构形式的选择,指出了微细尺度下气体静压轴承的设计要点;运用气体静压润滑的基本原理对气体轴承的结构及运行参数进行了分析,获取了径向轴承和止推轴承的参数设计;通过气体轴承静态性能的计算,从承载能力方面验证了将所设计的气体轴承应用于Power MEMS准气体动力循环发动机中的可行性.     

不等面积油腔滑阀反馈节流径向轴承刚度分析及其在冷轧机上的应用

一、前言近年来静压新技术在国内应用愈来愈广,对于具有对称等面积的油腔结构的静压轴承,已经有了较多的理论分析、设计计算和实际应用。静压轴承逐步推广应用于大型机床,解决具有各种特殊要求载荷条件,提高轴承的承载能力,可以采用不等面积油腔结构的静压轴承。本文就图1结构的轴承,通过引进面积比等参数,导出其无量纲的刚度曲线方程,提出计算方法和设计参数的一些选取方案,并将它应用于广州第三軋钢厂的冷軋机的设计计算上。     

新型动静压轴承试验台的设计与研究

为深入研究不同工况下动静压滑动轴承的静、动特性,设计、制造和调试成功了一台通用的新型动静压轴承试验台。在该试验台能进行静压和动静压轴承的静特性和动特性试验,并能进行实验数据的自动采集与处理。为中小型滑动轴承设计提供一整套有效的实验研究方法和设备。     

高精度空气静压轴承的研究

空气静压轴承是高精度轴承的发展方向之一。 文中阐述了高精度空气静压轴承的基本原理、设计特点和设计理论。将常用的孔式节流器的环形孔改进为倒角孔,通过气膜压力、轴承刚度等测量的结果表明:采用倒角孔节流器的轴承不仅能减小气体散流、非轴向流和负压的能量损失,而且在不改变轴承间隙和节流小孔孔径的条件下改变表压力比值,提高轴承的回转精度和刚度。 本文还介绍了高精度空气静压轴承的实验装置、制造方法,以及供气装置。     

轧辊磨床砂轮主轴轴承的故障修复

通过对静压轴承工作原理的阐述,分析了50″磨床砂轮主轴轴承故障产生的原因.在检修中,采取各种措施保持轴承轴颈外表面与轴承内表面的间隙,保持静压轴承内腔的液阻,建立静压轴承的压力,从而排除静压轴承故障,达到修复的目的.     

圆隙缝动静压轴承承载刚度分析

提出了一种新型动静压滑动轴承－圆隙缝动静压轴承，分析了该轴承的承载能力和刚度及刚度及设计参数对它们的影响，结果表明，该轴承性能优于传统的隙缝式轴承，且加工方便，很有应用前景。     

浮环动静压轴承的稳定性研究

动静压浮环轴承因具有承载能力高、结构紧凑、摩擦功耗低等优点 ,常被用作高速旋转设备的支撑系统。但当转子高速旋转时 ,轴承的油膜就成为转子系统丧失稳定性的原因之一 ,本文在建立内外膜相互作用力学模型的基础上 ,采用Routh Hurwitz判别法等方法 ,推导出浮环动静压轴承的稳定性判别准则和失稳加速度的计算公式 ,为动静压浮环轴承的稳定性设计提供了理论判据     

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…     

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。     

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     

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     

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

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

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.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.