金属材料熔点温度多个热物性的测试

通过测定固、液相界面的移动速率来确定金属及合金在熔点温度附近的导热系数、导温系数、电阻率等多个热物性参数。对于熔点温度较低的镓、伍德合金熔点热物性参数可用相变导热反问题的近似分析解求得,对于熔点温度较高的铅、锌的热物性参数可用数值计算与实验相结合的方法测定,并设计了相应的测试装置。测试所得的结果与文献数据吻合较好,误差小于15％,而且测量较简便,该方法可用于金属及合金相变条件下固、液相多个热物性的测试。图2,表1,参10。     

烟草导热系数与含水率、堆密度的综合关系

综合了本课题组长期对烟草导热系数的研究成果，推导出了烟叶和烟丝堆积床等效导热系数与含水率及堆密度的关系式，其计算值与实验值很吻合，并给出了根据一般含湿状态的实验数据得到的若干种不同产地不同级别烟草导热系数基准参数．这一工作为建立烟草热物性数据库奠定了的基础，并推进了对多孔介质导热系数研究的深度．     

金属熔点热物性测试及计算机在线检测

在研究热物性测试新方法的基础上,利用ＰＣＬＤ－７７９多通道隔离板和ＰＣＬ－８１２ＰＧ多功能数据采集、控制卡,通过计算机编程,开发了友好的用户界面,实现了金属熔点附近热物性测试过程中参数的自动检测与条件控制,保证了实验过程中测试系统所要求的边界条件,提高了测试精度;也为热物性测试新方法的系列研究提供了新的测控手段．     

岩土热响应测试及应用中的问题探讨

岩土热物性参数是地源热泵系统设计的重要基础依据,其准确程度决定着地源热泵系统运行的可靠性和经济性。本文介绍了岩土热物性测试设备构成及数据处理模型,并对热响应测试的某些问题进行了讨论。热响应测试是地源热泵工程应用的基础工作,具有重要意义。目前仍需要对其计算模型、测试方法及装置进行研究。     

生物组织热物性参数测试技术

简要介绍了生物组织热物性参数测试技术中具有阶段性突破的几种测试方法，并对其进行评述， 在此基础上对生物组织热物性参数测试技术的发展方向作了简要的论述     

高精度流体热物性测试实验系统的研制

在分析各种流体热物性参数测量要求的基础上,借鉴前人研究经验,结合最新的温度、压力等参数测量与控制技术,完成了流体热物性测试用的温度测量系统、高精度控温油/水槽、高精度控温酒精槽、压力测量系统、真空及配气系统、配套的测试与控制软件等的研制与开发,最终形成了一套相对完整的测试实验系统平台.在实验系统的运行范围内,最佳的温度测量不确定度小于±1mK,恒温槽15min的温度波动度可优于±1mK,压力测量的准确度为量程的0 01%.大量的实际运行结果表明:新研制的流体热物性测试实验系统性能稳定,测试结果可靠,为目前正在进行的流体热物性测试自动化研究奠定了良好的基础.     

基于LabVIEW的食品物性检测系统的研究

基于LabVIEW虚拟仪器技术、计算机系统集成技术和单片机技术,改进了食品物性分析仪,设计了食品物性检测系统.根据检测到的弹性力和位移等数据,通过教字分析得到弹性和酥脆度等物性参教;利用基于虚拟仪器的LabSQL数据库访问工具包,实现了对保存检测数据的数据库的查询和修改,进一步扩大了虚拟仪器技术的测试和应用范围.实验表明,设备运行可靠,且测试数据精确.     

生物热物性全参数辨识技术及其切片实验研究

提出了一套可用于同时确定生物在体组织中随空间变化的导热率K、血液灌注率W_b和代谢热产率q_m以及导温系数α的新方法,从而克服了传统生物热物性测试技术中只能测量常物性的K、W_b和α而q_m难以利用Pennes方程测出的不足,为同时考察活体组织非均匀热参数的空间分布规律找到了一条可行途径,这是一种具有普遍意义性的方法.文中给出了一个针对大鼠头部组织的物性辨识算例,并采用切片实验考察了该方法的实际应用问题,发现采用表面力,热的办法测取材料热物性时,所得结果的精度受热渗透深度限制,并继而提出了采用空间加热措施以提高物性测试精度的设想.     

第7届亚洲热物性会议

第7届亚洲热物性会议于2004年8月23～28日在合肥和黄山举行。亚洲热物性会议是世界上3个（欧洲、美洲、亚洲）系列热物性会议之一，始于1986年，由王补宣院士和日本N.Seki教授倡议创办，每3年举办1次，先后在中国、日本、韩国、印度举办过。本次大会经中国科协批准由中国计量测试学会主办、中国科学技术大学承办。会议主席由中国科学院院士、清华大学王补宣教授担任，会议国内组委会主席由中国工程院院士、中国科大教授范维澄担任，会议执行主席由中国科大工程科学学院热科学和能源工程系陈则韶教授担任。     

低温物性多功能测试系统

本文给出一套测量固体常用低温热参量的计算机控制多功能测试系统，可测量样品的电阻随温度的变化曲线Ｒ（Ｔ）、０～１．８×１０３ＭＰａ压力范围内电阻的温度特性Ｒ（Ｔ，Ｐ）、比热曲线Ｃ（Ｔ）及其ＡＣ磁化率，温区从液氮温度至室温．该系统集固体基本低温物性测量为一体，精度高，测量迅速、方便，为低温领域的物性分析（特别是高温氧化物超导体的研究）带来了极大的便利．     

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.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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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.     

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     

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.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。