平流层飞艇光伏电池传热特性

太阳能是平流层飞艇的理想能源,其热特性与飞艇浮力,蒙皮强度息息相关。准确预测飞艇的温度场是飞艇设计的重要步骤,但现有研究缺乏对太阳能电池的热特性分析。本文提出了一种包括太阳辐射,天空、地面长波辐射,蒙皮红外辐射和对流换热的飞艇模型,将几何模型离散化,编写C++程序计算了和分析了光伏电池的转化效率,吸收率、发射率、热阻和飞艇朝向对飞艇热性能、光伏阵列输出功率的影响。结果表明,较大的光伏阵列转化效率,发射率和等效热阻有利于改善飞艇“超冷”和“超热”现象的改善。光伏电池的辐射特性对光伏电池和氦气温度的影响最大：吸收率从0.5增加到0.9,主氦气囊昼夜温差升高约11.2K,光伏电池最高温度升高约29.8K;发射率0.1增加到0.9,主氦气囊昼夜温差降低约15.3K,光伏电池最高温度降低约50.2K。本文计算结果为飞艇的热稳定性的优化提供参考。     

高空科学气球下降过程航迹与热性能耦合分析

考虑高空科学气球动力学与热力学耦合关系,研究分析下降过程飞行航迹与内部氦气热性能.建立高空科学气球热模型和下降过程动力学模型,包括太阳辐射模型、红外辐射模型、对流换热模型等,仿真得到了某高空气球下降过程高度、速度等飞行航迹参数和氦气体积、温度等热性能参数,分析了参数变化规律与变化原因.研究结果表明,高空气球下降过程存在严重超热现象,超热状态变化导致下降速度变化,下降速度变化又导致超热状态改变;下降初始阶段氦气排放质量对下降速度、下降时间和超热状态均存在重要影响.     

基于多层节点模型的平流层浮空器热力学分析

基于两节点热力学模型,研究多层节点模型的平流层浮空器热特性分析方法.对美国国家航空航天局的超长航时气球的仿真结果表明:多层节点模型可给出囊体不同部位的温度分布及氦气温度随时间的变化规律;高空气球囊体顶部和底部的昼夜温差明显小于平流层飞艇内氦气的昼夜温差;高纬度飞行时的氦气温差更小,降低驻空高度可降低氦气温度.研究结果对平流层浮空器热控设计具有重要的参考价值.     

极地海洋工程装备圆管结构的对流换热影响

电伴热是极地海洋工程装备防寒主要措施，而热平衡是对流换热的关键问题.以圆管构件为研究对象，采用有限元数值仿真软件Fluent数值仿真与模型实验相结合的方法，分析了圆管构件在风速为0～40 m/s、温度为-40～0℃的极地环境条件下对流换热系数变化情况；基于数值仿真数据建立了电加热圆管构件对流换热系数的预测模型.结果表明：增大风速和降低温度都会增加圆管构件的对流换热系数；温度低于-30℃或风速大于25 m/s且温度低于-20℃时，温度对圆管的对流换热系数影响增大；实测数据验证了该模型的合理性.     

一种新型的空调系统空气处理方法及其节能分析

针对现有空调系统空气处理方法存在的不足,提出一种热湿分段的空调系统空气处理方法.分析了热湿分段处理方法的原理和过程,通过建立热湿分段处理方法的节能数学模型,研究并得出了表冷器结构、空调回风状态对热湿分段处理方法节能效果的影响规律.结果表明:相对于常规空气处理方法,热湿分段处理方法在表冷器设计换热温差7 ℃、出风温度为16 ℃时,冷水机组COP提高达9.14%以上;在回风干球温度为25 ℃、湿球温度为21 ℃时,冷水机组COP提高达8%以上.     

平流层飞艇太阳能电池热性能数值模型

平流层飞艇太阳能电池的温度对电池转化效率有着显著的影响;同时在正午时分可能对飞艇蒙皮以及内部浮升气体的温度造成不利的影响,并恶化飞艇的"超热"、"超压"现象。因此,很有必要对平流层飞艇太阳能电池热性能进行分析;但是相关研究却不是很全面。建立了平流层飞艇太阳能电池热性能分析数值模型,包括太阳能电池的太阳辐射模型、多层热传递模型。基于该数值模型,开发了MATLAB仿真程序。设计并开展了飞艇太阳能电池温度地面测试试验,对所建的热模型进行了验证。在研究过程中,分析了太阳能电池在一天内的温度变化情况。此外,详细讨论了日期、隔热层、太阳能电池外部封装层透波率以及风速等因素对于太阳能电池温度的影响。可以为平流层飞艇太阳能电池的设计提供有用的参考信息,为平流层飞艇热控制及热设计提供依据。     

飞艇升空过程超压控制可视化仿真

基于Vega与Creator平台研究了飞艇升空过程中飞艇超压控制的三维可视化仿真技术,建立了飞艇升空过程的数学模型与适合研究飞艇升空过程中超压控制的大气模型,并在Creator平台上开发了飞艇的实体模型.基于所建立的数学模型和实体模型,在VC6.0环境下完成了飞艇升空过程超压控制可视化仿真系统,给出了可视化的仿真结果.通过仿真试验分析,结果表明数学模型可行,在设置的超压控制策略下飞艇对环境有一定的自适应能力,能够比较平稳地升到所设定的高度.     

金属大变形过程中温度场的Abaqus模拟

基于Abaqus有限元仿真软件,在考虑到变形热、摩擦热和接触热等因素的情况下,建立了轧件内部温度场的数学模型和轧件空冷及水冷的数学模型,并利用实验获得的金属高温物性参数,对金属的大变形过程进行了有限元建模和仿真,模拟了金属变形过程中纵剖面的温度场分布及变化规律。模拟结果表明,在金属大变形过程中,金属表面的温度变化较大,且是非线性下降的,而金属内部温度变化较小,同时温度与变形量之间相互影响;在热变形过程中,不能忽视金属与环境温度的热交换,这在一定程度上影响着金属表面的温度分布情况;金属与外界发生热交换,交换的热量与外界温度和换热系数有关;金属的变形热对温度场的分布有明显的影响。     

颗粒绕流圆管传热的数值模拟研究

干法粒化后的高炉渣颗粒余热回收工艺主要以空气为冷却介质,由于空气的比热容小从而导致热效率低,因此,提出用自流床余热锅炉来回收高温炉渣颗粒的余热.基于CFD软件,将流动的颗粒当作连续的黏性流体,建立了一个三维数学模型,对颗粒绕流圆管传热的过程进行数值模拟,并验证了模型的正确性,研究了颗粒入口速度、水入口速度以及水入口温度对余热锅炉换热效果的影响规律.数值模拟结果表明:增大颗粒和水入口速度,可提高换热效果;增大水入口温度,传热系数没有变化,但热回收率减小.     

基于斯特林制冷机的氦气氛高低温箱深冷试验研究

为了模拟航天产品试验所需极端温度环境和测试航天产品在较大升降温速率条件下的耐受能力,研制了区别于传统热真空罐的氦气氛高低温试验箱,其净空间尺寸为2m×2.2m,可以通过强制对流与辐射换热相结合的方式提高升降温速率.同时,以液氮和四缸两级斯特林制冷机为双冷源,对高低温箱的降温性能进行测试,考察了高低温箱内空间的降温极限以及达到多个目标温度的降温速率等.结果表明,在液氮与斯特林制冷机共同作用的条件下,通过氦气的强制对流、再将氦气抽除的技术手段,可使热沉温度降至-210℃以下.     

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.