煤矿镐形截齿的失效形式与对策

镐形截齿是目前国内外采煤及掘进机械上使用最广泛的一种切割工具.镐形截齿的各种失效形式中磨损失效占比最大约为80%～90%而其他形式失效仅占10%～20%,由于传统截齿硬质合金刀头与支承硬质合金刀头的齿体在硬度和耐磨性上差异过大使得实际使用中硬质合金刀头只产生较少磨损而支撑硬质合金刀头的齿体部分却产生了大量磨损支承强度急...     

扁截齿失效的有限元应力分析

本文运用有限元法,分别计算分析了扁截齿仅在截割力作用和同时在截割力、焊接残余应力作用及缺焊两种状态下的应力分布。对扁截齿硬质合金头脱落、崩刃及刀杆折断的原因,分别从相当应力及硬质合金头焊接面上的张应力、剪应力的分布进行了探讨。     

基于动力学分析的采煤机截齿可靠性

为了计算采煤机截齿的可靠性,对截齿进行了受力分析.将实际工况处理为随机变量,采用概率统计的方法确定采煤机截齿的工作应力及其材料强度.分析认为采煤机截齿的工作应力服从伽马分布和材料强度均服从正态分布,根据应力-强度干涉理论建立求解截齿可靠度的数学模型.为采煤机截齿的故障诊断提出了理论依据.     

硬岩掘进机截齿与齿座的有限元分析

为了明确硬岩掘进机截齿与齿座的受力和应力分布情况,确定其损坏原因,通过MATLAB软件模拟单个截齿载荷,利用ANSYS对单个截齿及齿座进行有限元分析。研究表明：单个截齿的受力随切屑厚度的变化而变化,截齿位置角在π/2处截齿所受的各向载荷最大。截齿的最大变形发生在刀头部位,齿座的最大变形发生在齿座前部。根据研究结果,有针对性地采取措施,可进一步减少截齿及齿座损坏,延长其使用寿命。     

负倒棱对刀头应力分布影响的研究

前言在大前角车刀上使用硬质合金刀头虽然使切削轻快,但由于硬质合金性脆、易崩刀,影响了硬质合金大前角刀具的进一步推广。为此,本文对大前角硬质合金刀具的负倒棱的作用做了理论分析。首先根据材料力学的知识建立了刀头在切削时的受力模型,用弹性理论分析了刀头内应力的分布及负倒棱的倒棱前角及倒棱宽度对刀头内应力分布的影响,然后根据光弹性原理,分析了用环氧树脂制成的大前角刀头模型在模拟自由切削铅的过程中的应力情况,并拍了光     

硬齿面刮削铣刀盘切削应力应变有限元分析

利用大型通用有限元分析软件ANSYS，对弧齿锥齿轮和准双曲面齿轮硬齿面刮削铣刀盘切削进行了应力应变的有限元分析，通过铣刀盘在各种改变参数条件下的应力分布图和变形图，预知刀盘切削时的应力应变大小及分布形式，优化出刀具切削时受力状况良好的刀具几何参数，进—步了解刀具几何参数对刀具强度、刚度等的影响规律，从刀具力学的角度找出刮削刀头易崩刃破损的结构因素。     

镐形截齿应力分布规律研究

利用有限元分析软件ANSYS对AM50型掘进机的镐形截齿进行应力分析得出镐形截齿的应力分布图。为了解镐形截齿内的应力分布规律，进一步改善镐形截齿的受力状况，提高镐形截齿设计质量和延长其使用寿命找到一条途径。     

纵轴式掘进机截齿排列的参数化设计

为了解决掘进机截割头截齿排列理论缺乏、难度大,设计水平低、截割性能差等问题,建立了截齿排列的参数化理论,讨论了包络面、等升角螺旋线、母线的连接、螺旋线上截齿的分布等问题。利用MATLAB GUIDE语言编制计算机程序,设计了"截割头形状设计"面板、"螺旋线设计"面板、"截齿分布"面板、对外接口等截齿排列参数化软件模块,并以实例介绍了纵轴式掘进机截割头截齿排列的参数化实现。结果表明,该方法丰富了截齿排列理论,使设计水平和工作效率明显提高。     

基于ANSYS的不同形状镐齿的有限元分析

为了研究镐齿形状对其强度的影响,取几何尺寸相同、结构形状不同的三种截齿进行比较分析,建立了三种不同形状镐形截齿的结构模型,利用ANSYS软件在同样载荷作用下对各个截齿进行应力分析,得出各截齿的变形图和应力分布图,掌握了每种截齿工作时各点应力大小和易受损的位置,所得结果为正确选择和合理设计截齿结构以及改进截齿的设计、改善镐形截齿的受力状况、提高截齿工作的可靠性和使用寿命提供了重要的依据.     

镐形截齿应力分布规律研究

利用有限元分析软件ANSYS对AM50型掘进机的镐形截齿进行应力分析得出镐形截齿的应力分布图.为了解镐形截齿内的应力分布规律,进一步改善镐形截齿的受力状况,提高镐形截齿设计质量和延长其使用寿命找到一条途径.     

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.