新型高强度铸造铝合金的热处理工艺研究

本论文采用正交实验,对新型高强度铸造铝合金的力学性能影响因子进行分析,确定出最佳的热处理工艺：固溶处理温度550℃,固溶处理时间16h,时效温度150℃,时效时间10h。在此工艺条件下铝合金具有优良的力学性能,抗拉强度σb可达到498MPa,延伸率δ为6．8％。     

新型高强Al-Mg-Si合金热处理工艺

结合力学性能测试、扫描电镜分析、DSC热差分析和金相组织观察,对一种新型高强Al-Mg-Si合金挤压材的固溶与时效制度进行了系统研究.同时得到了该合金挤压材不同时效温度下的力学性能,为工厂实际生产中热处理规程的制定以及深入研究提供详细的参考依据.该挤压材过烧温度572℃,熔化温度为594℃;对其进行560℃/2h固溶处理后,以及170℃/12 h人工时效热处理,可达到最佳峰值时效效果,其抗拉强度、屈服强度和延伸率可依次达到406,340 MPa和18.37%;该合金挤压材发生了充分的再结晶,致使加工硬化完全消除.     

半固态Al-Cu-Mn合金锻件的热处理工艺与组织

利用正交试验法,对Al-Cu-Mn合金半固态锻压件进行了固溶时效热处理.通过对硬度指标的分析,获得了热处理的最佳工艺参数.同时分析了时效后的显微组织.结果表明,Al-Cu-Mn合金半固态锻压件在固溶温度540℃、固溶时间13 h、时效温度165℃、时效时间8 h下,其维氏硬度值可达130 MPa以上;且析出相均匀、弥散地分布在基体上.     

高强耐磨形铝青铜的热处理工艺

采用正交试验方法优化了一种新型高强耐磨变形铝青铜合金的热处理工艺，并研究了时效温度和淬火介质对合金力学性能的影响。试验结果表明，合金的最佳热处理工艺参数为850℃保温1h，火淬，350℃时效1h，空冷。时效温度对合金性能有显著影响，在400℃以下，随时效温度的升高，合金的强度增大，而塑性无明显变化；在400℃以上，随时效温度的升高，合金的强度降低，而塑性显著增大。淬火介质的类型和温度影响合金的力学性能，常温水是理想的淬火固溶介质。     

高强耐磨变形铝青铜的热处理工艺

采用正交试验方法优化了一种新型高强耐磨变形铝青铜合金的热处理工艺 ,并研究了时效温度和淬火介质对合金力学性能的影响 .试验结果表明 ,合金的最佳热处理工艺参数为 85 0℃保温 1h ,水淬 ,35 0℃时效 1h ,空冷 .时效温度对合金性能有显著影响 ,在 4 0 0℃以下 ,随时效温度的升高 ,合金的强度增大 ,而塑性无明显变化 ;在 4 0 0℃以上 ,随时效温度的升高 ,合金的强度降低 ,而塑性显著增加 .淬火介质的类型和温度影响合金的力学性能 ,常温水是理想的淬火固溶介质     

改善锻铝合金强韧性的热处理工艺及机理研究

研究了改善１０号锻铝强韧性的热处理工艺,结果表明,合金经５００℃３００ｍｉｎ固溶淬火,１６７℃,６～１０ｈ时效工艺处理,达取最佳的强韧性效果,同时,对该合金的强韧化机理进行了探讨。     

高强度铝合金热处理工艺研究

高强度铝合金是多元Al－Si合金，本文在确定最佳成份及铸造工艺条件一定的情况下，研究了热处理工艺对机械性能影响的关系．对该合金经不同的固溶温度，不同的时效温度和时效时间进行了试验研究，结果表明：固溶后采用155±5°×6h时效工艺，合金可获得最佳的机械性能．     

高强耐磨铝青铜热处理工艺的研究

通过正交试验和对比试验优化了Cu14AlX铝青铜合金的硬化热处理工艺 ,找出了热处理过程中影响该合金硬化性能的 4种因素的主次顺序是 :固溶温度、时效时间、时效温度和固溶时间 .进一步研究证明通过 84 0～ 880℃油淬固溶和 5 70～ 6 0 0℃空冷时效处理 ,合金能够得到 4 8.2HRC的最高硬度 .硬化的原因是时效过程中共析相γ2 的均匀细化和κ相的弥散析出 .     

ＫＳ１２７５合金的时效过程研究

系统地研究了ＫＳ１２７５合金的热处理时效过程,总结出最佳热处理工艺是５２０℃固溶处理,２２０℃人工时效８h。     

消除7A05铝合金板材各向异性的热处理工艺

为提高7A05铝合金热轧板材的综合力学性能并减少各向异性,对7A05铝合金固溶、预时效、时效和形变处理等工艺对性能的影响进行了系统的研究. 比较了供货态、形变态、回归(RRA)态和采用预时效形变热处理的优化态热处理工艺对综合力学性能的影响. 结果表明:固溶的最佳温度为480 ℃,单级时效最佳工艺为120 ℃,24 h,双级时效中第一级时效最佳工艺为90 ℃,8 h,最佳形变为25%. 通过金相组织和力学性能测试结果表明:由于预时效析出促进形变热处理时亚晶等轴化,优化态强度高,进一步改善了合金性能,减少了轧制板材纵横向力学性能各向异性倾向.     

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.     

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…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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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。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

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