氩弧熔铸TiC-TiB_2/Fe复合材料的组织与耐磨性

为改善合金材料的耐磨性能,采用氩弧熔铸技术,以Fe、Ti、B和C粉为原料,按质量分数比45∶30∶20∶5制备原位合成TiC-TiB2/Fe复合材料。通过扫描电镜、X射线衍射仪、洛氏硬度计及摩擦磨损试验机对复合材料的显微组织、物相、洛氏硬度和耐磨性进行分析研究。结果表明:复合材料由原位生成的TiB2和TiC增强颗粒相及α-Fe相组成,颗粒呈块状、板条状和多边形,且颗粒结合地很紧密。复合材料的平均洛氏硬度约为9.37 GPa。在室温干滑动磨损条件下,该熔铸复合材料的耐磨性约是GCr15工具钢的6倍。该研究为原位合成TiC-TiB2/Fe复合材料的制备提供了一种新方法。     

高韧性耐磨钢（W2）的研制

良好的耐磨性能与韧性通常很难兼之，采用高合金风生产成本较高，W2钢则两种特性兼优，且合金成份成本较低，采用合理的化学成分，冶炼工艺，锻造方法和热处理条件，得到了洛氏硬度60．2，冲击韧性σk115J/cm^2的W2钢，其合金元素总量（W＋Mo V Cr)为M2高速工具钢的40％左右，洛氏硬度和耐磨性能达到M2水平，冲击韧性σk则比M2高1．5倍，W2钢性能亦优于日本新研制开发的ES钢，其吨钢生产成本约为M2钢的35％－40％左右。     

Mo和变质处理对高钒高速钢耐磨性的影响

为讨论Mo元素和变质处理对高钒高速钢耐磨性的影响,制备高钒钼高速钢.通过金相法、X射线衍射和摩擦磨损实验对高钒高速钢的显微组织、物相组成和耐磨性能进行分析.结果表明：热处理后的未变质高钒高速钢、变质高钒高速钢和变质高钒钼高速钢的组织主要由马氏体、Fe3C和V2C组成;Mo元素和变质处理使高钒高速钢的碳化物明显细化,大量颗粒状碳化物弥散分布;变质高钒钼高速钢在室温下干磨损60 min,失重量为0.0119 g.该研究为高钒高速钢的发展提供了理论依据.     

热处理对高铬铸铁组织和性能的影响

研究了不同热处理状态下高铬白口铸铁显微组织,探讨了热处理对高铬铸铁冲击韧性和硬度的影响,并确定了组织与性能的相关性。分别采用金相显微镜观察热处理后高铬铸铁显微组织,洛氏硬度计测定高铬铸铁的硬度,冲击试验机测定冲击韧性。结果表明：高铬铸铁随着淬火温度的升高,硬度先升后降,冲击韧性则相反。在1 000℃淬火空冷,并在400℃回火时,材料可以获得良好的综合力学性能。     

硅对中碳低合金贝氏体/马氏体复相耐磨钢的影响

研究了不同含量的硅元素和热处理工艺对中碳低合金钢的组织与性能的影响.在中碳钢中,加入少量的硅、锰、铬合金元素,采用中频感应炉进行熔炼,砂型浇注.炉料由废钢、生铁、硅铁、锰铁、铬铁组成,浇注出的试样用箱式电阻炉加热到910℃,保温2h,于硝盐槽中进行等温淬火,分别为280℃保温1.5h,2h和2.5h.对热处理后的试样和铸态下的原始试样进行洛氏硬度和冲击韧性试验,对比发现,经过热处理后的试样硬度和冲击韧性性能均有明显提高,采用金相显微镜对试样进行组织观察,发现热处理后的试样得到贝氏体与马氏体组织.试验表明:贝氏体与马氏体复相可以有效提高硬度和冲击韧性,冲击韧性最高为27.623J/mm2,洛氏硬度最高达到57.25.     

含镍低铬铸铁腐蚀磨损性能研究

采用MCF-30型冲蚀磨损试验机对两种不同热处理后的低铬铸铁进行冲蚀磨损实验.用扫描电镜(SEM)和X衍射仪等对其组织以及冲蚀后的形貌进行观察分析.实验结果表明,残余奥氏体的存在严重影响了低铬铸铁的耐磨性能;在冲蚀磨损中,过低的冲击韧性导致其表面成块状脱落,耐磨性差.     

Cr3C2颗粒增强型堆焊合金组织与性能分析

对加入Cr3C2的药芯焊丝制备的Cr3C2增强型堆焊合金组织和性能进行了分析。添加Cr3C2的自保护药芯焊丝堆焊工艺性能良好,堆焊表面少飞溅,无裂纹气孔。通过对比实验研究发现,加入Cr3C2的药芯焊丝制备的Cr3C2增强型堆焊合金组织细小,高温冲击韧性明显优于WC颗粒增强型药芯焊丝,合金组织中既有颗粒增强型药芯焊丝堆焊产生的颗粒增强相,又有高铬铸铁型药芯焊丝堆焊产生的高硬度初生碳化物,双重强化机制使堆焊层显微硬度达到含Nb高铬铸铁堆焊层的水平,平均硬度60 HRC以上。     

高钒高速钢与高铬铸铁的滚动磨损性能对比研究

以高铬铸铁为参照，在自制的模拟轧辊磨损试验机上研究了高钒高速钢的滚动磨损性能．结果表明：随磨损循环次数的增加，两种材料的磨损量均直线地增加，高钒高速钢的相对耐磨性是高铬铸铁的4倍以上；高铬铸铁中的裂纹主要由于M7C3的严重碎裂而萌生于M7C3的内部，高钒高速钢中的裂纹则主要萌生于VC与基体的界面，并沿VC的表面扩展．高钒高速钢中VC形状好、不易碎裂及基体硬度高是其耐磨性优良的主要原因．     

耐磨铸铁的研制及其耐磨性的试验研究

通过合金化的方式,制备了两种耐磨铸铁材料,研究了所制备铸铁的组织、相结构、硬度及其耐磨性能。研究表明:Ni-Cr-Mo铸铁形成白口组织,P铁的组织形貌为硬而脆的二元磷共晶(α-Fe+Fe_3P),XRD物相分析表明Ni-Cr-Mo铸铁中形成了新的化合物Cr_(13)Ni_5Si_2、Cr_3Ni_2Si、Cr_(23)C_6,P铁中为Fe_3Si、Fe_2Mn Si。硬度和磨损实验表明两种铸铁都具有较好的耐磨性,Ni-Cr-Mo铸铁的磨损量更低。     

耐磨高速钢辊环的研究

针对常用合金铸铁辊环耐磨性低,而硬质合成辊环成本高情况,采用离心铸造方法,开发了耐磨性能优良的高速钢辊环.实验证明,高速钢辊环的硬度达63～65 HRC,辊面硬度差小于2HRC,冲击韧性大于16 J/cm2.用于线材轧机预精轧段,使用寿命比合金铸铁辊环提高6～10倍,接近了硬质合金辊环的水平.     

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.