低温生成Fe—Al金属间化合物覆层组织结构分析

在500—600℃的低温下，用机械能助渗铝方法，在钢表面得到了Fe-Al金属间化合物覆层。用EPMA、XRD、TEM分析了金属间化合物覆层的组织结构。结果表明，金属间化合物覆层由Fe2Al5相以及少量的FeAl、Fe3Al和非晶态相构成，覆层表面断续分布着铁、铝氧化物颗粒，该氧化物颗粒先于Fe2A15、FeAl等金属间化合物形成。     

Fe3(Si1-x,Alx)金属间化合物的制备及其力学性能研究

采用真空电弧熔炼退火制备了Fe3(Si1-x,Alx)(x=0.2,0.4,0.6)Fe3Si基金属间化合物.通过XRD和SEM对制备出的试样进行表征,同时对其显微硬度、压缩强度及弯曲强度等力学性能进行了综合分析.结果表明,Fe3(Si1-x,Alx)金属间化合物仍然保持Fe3Si物相不变.Al的合金化改性降低了Fe3Si金属间化合物的显微硬度,有利于改善Fe3Si的脆性.Fe3(Si0.67,Al0.33)表现出较Fe3Si高的抗压和抗弯强度,这是其适中的有序度值与变形过程中加工硬化作用的综合结果.Fe3(Si1-x,Alx)表现出明显的二次解理特征,这利于断裂过程中裂纹能量的释放,从而提高其强度.     

Fe3Al网络结构增强Al基复合材料的磨损特性

采用机械球磨及退火工艺制备Fe3Al金属间化合物粉体,通过有机前驱体的制备、负压浸渗法制备Fe3Al/Al网状结构复合材料。经扫描电镜、摩擦磨损试验机分析研究该材料的磨损性能。结果表明,Fe3Al/Al复合材料的磨损失重量随网络结构增强体Fe3Al体积分数的增加而降低,随磨擦时间和摩擦载荷的增加而增加。当φ(Fe3Al)=20%,摩擦载荷=90 N,磨球转数=1 000 r/min,摩擦时间=20 min时,试样磨损失重量仅为24 mg,较纯铝试样降低了85%;Fe3Al/Al复合材料磨损机制是在"磨粒磨损"和"黏着磨损"间交替往复混合进行。     

Al/Fe/Ni界面固态扩散实验分析

采用“铆钉法”制备了含有Al／Fe／Ni和Fe／Ni两相界面和Al／Fe／Ni三相交接点的扩散偶,利用光学显微镜、扫描电镜背散射技术和微区能谱分析技术对扩散偶的界面反应区域进行了观察分析。结果表明,两相界面处金属间化合物新相的生成受扩散动力学和热力学双重因素的控制,Al／Ni和Al／Fe两相界面均生成富Al金属间化合物,Fe／Ni界面上只存在界面模糊的固溶体组织,Al／Fe／Ni三相交接点附近没有三元金属间化合物生成。     

Fe_3Al基金属间化合物固溶强化和析出强化

Fe3Al金属间化合物作为一种结构材料逐渐被广泛应用在许多工程领域,许多研究致力于改善Fe3Al的室温塑性和高温强度。固溶强化和析出强化被认为可以改善力学性能。微合金化是主要的方法。本文综述了合金化Fe3Al的强化机制。其推广使用与一些相关的实用化技术是分不开的。对Fe3Al金属间化合物微合金化被认为是改善其综合性能的有效途径之一,本文主要综述近年来微合金化对Fe3Al金属间化合物性能的方面的影响。     

超重力场辅助燃烧合成技术制备Fe3Al合金及其抗氧化性能研究

本课题利用超重力场辅助的两步燃烧合成技术成功制备了Fe3Al合金.首先利用Al/Fe2O3之间的铝热反应释放的高热量使得产物(Fe和Al2O3)转变成高温混合熔体,Fe熔体在1000 g超重力场的作用下迅速从高温混合熔体中分离,并和底部的纳米铝粉发生二次燃烧合成,生成致密的Fe3Al金属间化合物.Fe3Al样品中仅存在...     

Ni3Al金属间化合物材料的制备工艺和研究发展现状

Ni3Al金属间化合物由于具有优良的力学性能被广泛应用于工程领域和工业领域中。该文讲述Ni3Al金属间化合物材料的概述和制备工艺，力学性能，研究发展现状和应用现状等。该文讲述Ni3Al金属间化合物及其复合材料的制备工艺，力学性能和其他性能以及研究发展现状等，并介绍了Ni3Al金属间化合物在工程领域中的应用。该文最后介绍了Ni3Al金属间化合物材料的研究发展趋势和研究发展方向。     

光束合金化合成Fe-Al系金属间化合物涂层的微观特征

为了改善钢铁材料的耐高温腐蚀性能,用光束合金化方法在45钢表面合成了Fe-Al金属间化合物涂层.采用扫描电子显微镜、能量弥散X射线分析和X射线衍射研究了光束合金化工艺参数(粉末预置量m和热输入量q)对合金化层的化学成分、显微组织及其物相组成的影响.实验结果表明: 减小比能量(E＝q/m)将导致合金化层的熔宽和熔深减小,从而使合金化层含Fe量减少,含Al量增加; 该实验条件下,获得了Fe/Al原子数比为2.4～19.2的合金化层.由比能量决定的Fe/Al原子数比是合金化层显微组织及其物相组成的重要影响因素,合金化层的显微组织有3种类型: α-Fe固溶体、α-Fe固溶体 Fe3Al金属间化合物及FeAl AlFe3C0.5金属间化合物.降低热输入或增加粉末预置量均可引起合金化层中Fe/Al原子数比的降低,有助于Fe-Al系(Fe3Al或FeAl)金属间化合物的合成.     

机械合金化制备纳米Al_(70)Fe_(25)Ni_5合金

采用X射线衍射(XRD)、扫描电子显微镜(SEM)、差热分析仪(DTA)等研究了Al70Fe25Ni5元素混合粉末在机械合金化过程中的结构演变及热稳定性.结果表明:球磨0.5h后有部分非晶生成,球磨5h后的粉体,退火处理后生成Al5Fe2和Al3Ni2金属间化合物.球磨500h后得到纳米金属间化合物.     

原位合成VC和TiC颗粒对Fe3Al基合金显微组织的影响

以Fe3Al金属间化合物作为基体,采用反应铸造法制备了含VC,TiC颗粒Fe3Al基合金并研究了颗粒相在Fe3Al合金中的形成机理及颗粒相的加入对Fe3Al基合金显微组织结构的影响。结果表明,TiCp在高温液态熔体中原位合成,且在基体中均匀分布,可以作为异质形核核心而细化Fe3Al基合金铸定组织,从而改善Fe3Al合金的热加工性能;VCp是在固相中形核并长大的,对铸态组织的细化作用下明显,但其对热加工后再结晶组织的细化作用甚于TiCp。     

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).     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.