面心纯铝轧制织构的晶体塑性有限元模拟

基于率相关晶体塑性本构模型,分别将Taylor模型和有限单元模型两种多晶模型嵌入大型有限元程序ABAQUS,实现了晶体塑性学有限元模拟. 直接将电子背散射衍射(EBSD)获取的晶粒初始取向输入晶体塑性有限元模型,预测了两种不同应变情况下面心1 050纯铝轧制织构的演化. 模拟结果与EBSD实验测得的织构演化结果有较好的一致性,随着变形程度的增加,预测织构与实测织构变得更加锋锐. 经过比较,Taylor型模型预测出了{4 4 11}〈11 11 8〉的Dillamore取向,而有限单元模型预测出了铜型织构取向,比Taylor模型预测结果更接近实验验证结果. 两种模型并不能预测出{011}〈211〉黄铜取向、{123}〈523〉S取向、{011}〈100〉Goss取向及其他理想取向.     

深冲用冷轧薄钼板晶体空间取向分布的研究

本文利用晶体取向分布函教研究了国产冷轧钼板的直轧和交叉轧制织构。结果表明,直轧钼板的基本织构组分为:{001}〈110〉织构、轧向〈011〉纤维织构和轧面{111}纤维织构;交叉轧制使钼板中{001}〈110〉织构和{111}纤维织构同时明显增加。通过对晶体取向分布特征的全面分析,初步探讨了轧制过程中晶粒转动的规律,为提高钼板深冲性能提供了一定的依据。     

Ta-7.5％W在退火过程中的组织和织构演变

通过金相组织观察、透射电子显微镜(TEM)及显微硬度测试,研究冷轧变形量为95％的Ta-7.5％W合金箔材在1 050,1 200和1 360℃退火时的组织和性能变化,并采用取向密度函数(ODF)分析在此过程中其织构演变规律.对其实验结果进行研究发现:冷轧态Ta-7.5％W合金硬度为HV 300,经1 360℃退火后硬度迅速减小,说明此时合金已发生回复再结晶.轧制后的Ta-7.5％W合金箔材具有各向异性,在轧面∥{111}取向上形成位错胞亚结构,在轧面∥{100}取向上形成了形变带,冷轧态的主要织构为{001}〈110〉,{112} 〈110〉和{110}〈110〉织构;在1 200℃退火时,在轧面∥{111}取向上,再结晶通过亚晶界迁移、亚晶长大形核,而在轧面∥{100}取向上,主要是通过亚晶转动、聚合形核;{001}〈110〉织构增强,{112}〈110〉织构减弱;在1 360℃退火时,{001}〈110〉织构急剧减弱,{111}〈112〉织构增强.     

异步轧制对IF钢冷轧及再结晶织构的影响

研究了异步轧制对IF钢的冷轧及再结晶织构的影响,并且将模拟的剪切应变随辊速比的变化规律应用到以Taylor模型为基础的织构模拟中,分析了剪切应变εxz值对形变织构的影响.结果表明:随着异步轧制速比的增加,冷轧的α纤维织构组分逐渐减少,γ纤维织构组分稍有增加.异步轧制时,附加的切应变是造成这种变化的主要原因;{111}〈uvw〉再结晶晶核的形成与{001}〈110〉织构组分无关.异步轧再结晶{111}〈112〉织构组分体积分数明显多于同步轧,这是由于在冷变形状态下,{111}〈112〉织构组分就明显高于同步轧制条件.     

3004铝合金在轧制及退火过程中织构的演变

应用取向分布函数(ODF)研究和分析了热轧、冷轧及退火对3004铝合金织构的影响·结果表明,热轧后织构类型为(100)[uvw],且(100)[011]旋转立方织构为最强;在冷轧过程中,所有样品的冷轧织构表现为典型的铜式织构特征,随形变量的增加,织构由弱到强,最后稳定在铜织构、黄铜织构和S织构3个织构组分;冷轧样品退火后,退火织构主要由立方织构、退火R/S织构和铜织构组成,其中在300℃和400℃的退火样品中存在强度较高的再结晶立方织构{001}〈100〉,100℃和200℃的退火样品中再结晶立方织构{001}〈1...     

高硅钢近柱状晶初始组织的形变、再结晶行为及磁性能

采用电子背散射衍射技术对高硅钢近柱状晶初始组织直接热轧、温轧、冷轧和退火组织及织构演变进行分析,并测定相应退火板的磁性能.该实验条件下组织与织构演变规律体现了表层剪切细小组织和中心层粗大组织的竞争关系,其中中心层组织与原始立方取向相关或表现为α线取向.柱状晶的影响在最终退火组织中仍存在,少量立方取向区域可遗传到最终退火板中,虽然没有大量出现,仍有效削弱了{111}织构.形变退火过程中与原始立方取向线有关的晶粒尺寸普遍较大,有利于磁性.样品最终的磁感应强度低于文献报导的强{120}〈001〉或{100}〈021〉织构样品,但高于普通无取向高硅钢,且轧向和横向磁感应强度值差异小,所以柱状晶组织有利于无取向高硅钢的制备.     

3%Si无取向硅钢异步轧制织构的演变

对无取向硅钢常化态板材经过异步轧制,轧制速比为1.06,经过一次冷轧到0.5 mm厚,压下率为77.3%,并在保护气氛下进行再结晶退火,考察了异步冷轧织构和再结晶织构形成及演变.常化态板材的初始织构组分以{110}和{113}织构为主,异步冷轧织构主要是由α织构和γ织构组成,快慢辊侧的织构类型没有变化,但慢辊侧α织构和γ织构的取向密度明显高于快辊侧;再结晶退火后α织构取向密度明显减弱,而γ织构的变化主要是{111}〈110〉织构组分的取向密度减弱,{111}〈112〉织构组分的取向密度加强.     

最大熵技术和它在织构分析中的应用

使用最大熵技术,探索了形变量ε对纯铁冷轧织构的影响。结果表明,在形变过程中,形成两组主要织构组分:{100}<011>和{111}丝织构,其中{100}<011>随形变量增加而增加。相反,当形变量大于 54％时,{111}丝织构却倾向于不变。     

微量元素对高纯铝箔立方织构的影响

采用晶体取向分布函数(ODF)研究和分析了在高纯铝中分别加入不同含量的微量稀土或铍对成品高纯铝箔立方织构的影响．研究结果表明添加微量稀土和铍,能改变高纯铝箔变形织构组分含量,单独加稀土时,形变织构变化不大;在单独加铍时,其S取向{123}<634>和Cu取向{112}<111>变化较大,随铍含量增加,其S取向密度f(g)减少,Bs{110}<112>取向密度增加．再结晶退火后,随稀土加入量增加,立方织构{100}<001>取向密度增加,R织构{124}<211>取向密度减少;铍添加较少时能增加成品箔材中立方织构{100}<001>强度,但随铍含量增加,立方织构含量急剧减少,R织构强度相应增加．稀土和铍在铝中溶解度都极小,与铁等微量杂质元素可能形成化合物析出后,能净化基体,减小铁对形成立方织构的阻碍作用,促进再结晶立方取向核心的形成与长大,增加立方织构比例．     

冷变形织构沿纯铜线材径向分布的研究

为了探讨显微组织与形变织构的相关性,对纯铜线材运用精确的线材织构测定方法进行织构测定,采用取向分布函数法(ODF)分析了织构沿纯铜线材径向的分布.研究表明:单晶铜线材表面织构组分由〈100〉,〈112〉与〈110〉组成.由表及里〈100〉呈现增加趋势,并在中心层成为主要织构组分;〈112〉先增加后减少;〈110〉呈现减少趋势.多晶铜线材表面织构组分有〈100〉,〈111〉,〈112〉.由表及里〈100〉呈现先增加后减少;〈111〉呈现增加趋势,并在中心层与〈100〉成为主要织构组分;〈112〉先减少后增加.     

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.