凸轮机构动力学分析的仿真研究

提出了运用领导 具技术对凸轮机构进行动力学分析的方法，介绍了在simulink下的凸轮机构仿真过程，通过一实例得出：该方法具有运算简便、精度高、速度快等特点，同时，通过对仿真参数的修改，可进行凸轮机构的参数优化，在凸轮机构设计过程中，可大幅提高其设计精度和效率。     

平行分度凸轮CAD/CAM系统的研究与开发

为研究通用平行分度凸轮仿真系统,实现平行分度凸轮CAD/CAM一体化,通过对平行分度凸轮分类,再对每一类型的凸轮进行分析与综合,得出凸轮的理论轮廓曲线方程和工作轮廓曲线方程.采用VC++与UG软件开发了平行分度凸轮CAD/CAM系统,该系统给出了界面友好的参数输入对话框,能够完成机构参数的自动综合与轮廓的自动生成,以UG要求的格式保存数据,转入UG环境,生成三维实体模型进行加工仿真,最后通过实例验证了该系统的可靠性.     

弧面分度凸轮的实体造型及数控加工

为了将复杂的凸轮机构可视化,实时地模拟其真实的运动状态,利用空间啮合原理,建立弧面分度凸轮的轮廓曲面方程.采用模块化设计思想,基于VC 面向对象的方法及UG二次开发技术,建立弧面分度凸轮参数化设计系统,实现具有真实感的弧面分度凸轮的三维实体造型.在UG环境下进行装配、仿真与干涉检测,验证设计的合理性.UG实体造型完成后生成数控加工程序,实现对弧面分度凸轮的数控加工.     

基于平面盘形凸轮CAD系统知识库的构建

凸轮机构的设计是一个多因素、多层次的复杂过程,许多公式非标准化.采用专家知识库,通过Visual Basic的开发并结合Access数据库,实现对知识库的维护和修改,从而构建凸轮机构智能设计系统,方便用户使用,该系统具有易用性和智能性,也对改善凸轮机构的设计具有现实的意义.     

高速盘式凸轮的优化和动态设计

本文应用九阶多项式表达凸轮的外形曲线，根据实际设计要求，用优化方法确定该多项式的系数及凸轮机构的结构参数；讨论了系统弹性对凸轮轮廓和接触应力的影响，并且提出了对凸轮轮廓进行修正的方法。     

基于Pro/ENGINEER的凸轮机构设计

通过对凸轮机构的设计特点的分析,针对传统的设计方法中的一些缺点,利用Pro/E软件进行凸轮设计的方法,并进行凸轮机构设计和运动仿真。利用从动件的位移数据表创建图形特征,然后利用该图形特征和关系式工具创建可变截面扫描特征,可准确、快速的生成凸轮实体;利用Pro/E的装配模块,建立机架、凸轮、从动件的连接关系,利用机构仿真模块设定凸轮机构,伺服电机参数等,通过对机构进行运动学仿真和运动结果的分析,提高机构设计的准确性。     

应用单参数曲面族包络面理论计算和分析圆锥凸轮机构

用近代微分几何理论讨论空间凸轮廓面是当今空间凸轮机构设计研究的前沿方向之一．本文应用单参数曲面族包络面理论对摆动从动杆圆锥凸轮机构空间廓面进行了讨论,给出了廓面的数学表达式,构造性地推导出机构的压力角、廓面主曲率等几何特性参数的解析表达式．为空间凸轮机构的计算机辅助设计与制造及可视化处理提供了一条新途径．同时,利用本文结果,不难钭文献[10－11]的结论作为特例导出．本文最后给出了一应用实例,以验证文中结论．     

应用Pro／E对凸轮机构动力学分析的方法

本文从运动仿真角度入手，详细介绍应用野火版Pro／E3．0软件对凸轮机构的运动过程进行分析并记录运动过程中的参数，通过对得到的测量参数的进行系统性分析，提出科学的见解，帮助产品设计者检查所设计的模型是否符合生产实际的需要以及发现在运动过程中出现的问题，有针对性的对零件的欠合理部分进行评估和再设计，以提高产品的性能，使之更好的满足生产实际需求.     

直纹面在弧面凸轮设计中的应用

结合弧面凸轮传统设计常用的空间包络曲面共轭原理的方法及弧面凸轮分度机构的运动特点,利用直纹面及其等距曲面原理生成弧面凸轮的廓面,并在CAD软件UGNX环境下,建立了参数化弧面凸轮的实体模型,这种方法有利于弧面凸轮的快速设计和评估.     

基于Solidworks的平面凸轮机构参数化设计

基于Solidworks对平面凸轮机构进行全参数化设计,根据输入的参数自动生成凸轮的实际轮廓线,并应用虚拟装配与运动仿真技术,实现设计的可视化及机构设计的合理性分析与验证。     

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.     

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.     

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).     

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.