周期性环境条件下相变材料对系统热控效果的影响

运行于户外周期性环境条件下的热控系统在工业领域有重要应用价值,降低系统能耗和提高温控效果是其性能改进关键所在.为此,采用实验和仿真手段研究了热控系统围护结构中相变材料(PCM)对系统热控效果的影响.典型气象日研究结果表明,相较于聚苯乙烯,PCM在广州地区能显著降低系统能耗(75.4%)、目标表面温度波动幅度(76.1%)和轴向温差(56.9%),在南京和吐鲁番地区可分别降低目标表面温度波动幅度41.3%和30.6%,但对系统能耗和目标轴向温差无改善;典型气象年结果表明,PCM在广州地区同样表现出热控优势,但热控效果对控温设定点、PCM相变范围和环境温度波动有很强的依赖性,当所选PCM相变范围包含控温设定点且与环境温度波动范围一致时,PCM能最大限度提高热控效果.     

大功率T/R组件相变温控平板热管的散热特性实验研究

为保证大功率相控阵天线T/R组件的长时间稳定工作，提出了一种相变储能平板热管的热控设计方案，该系统中的相变材料和平板热管分别发挥储热和热扩散的作用。实验对比了铝制平板热管和铝合金板的热扩散性能，以及它们分别和相变材料结合后的热控性能。实验结果表明，铝制平板热管的传热性能优于铝合金，在40 W时其冷凝端的最大温差为3.2℃,且等效热阻可维持在0.35 K/W以下；当热源置于侧边时，相比置于中间位置时的蒸汽扩散和液体回流路径较长，平板热管的热扩散性能下降；同时，与使用铝合金作为储热容器底部基板时的局部过热现象相比，采用相变储能平板热管的热控设计，可以将热源的热量进行均匀扩散，降低热流密度，从而表现出更好的温度均匀性，再通过相变储能的方式吸收热量，可以保证天线产品持续工作90 min时的结点温度控制在70℃。对于高纵横比的槽道式平板热管，需要进一步改良槽道的毛细结构，降低蒸汽扩散和液体回流路径的差异对热扩散性能的影响。     

相变贮热材料及其在太空中的应用

相变贮热材料是绿色材料，种类达4300多种，具有清洁和节能等优点。系统地介绍了相变贮热材料分类及其特点，讨论了相变贮热材料在太阳能热动力发电、航天器仪器仪表的恒温控制、舱外航天服方面的应用。     

一种耐高温多层热防护组件结构设计与性能研究

研究了由多种功能层材料组成的热防护组件的结构设计方法与热防护性能.利用仿真计算模拟了高温热环境下由不同厚度的面板层材料与隔热层材料组成的热防护组件的热响应行为,并通过石英灯加热考核验证了优化设计的热防护组件的耐温隔热与可重复使用性能.结果表明,致密的面板层材料具有优异的耐温性能,而由气凝胶组成的隔热层材料具有极低的热导率.根据目标环境匹配设计两种功能层材料厚度,可使多层热防护组件具备经最高温度1 600℃的加热考核后,背温仅为118℃的优异耐温隔热性能.      

变轨高温发动机热辐射对空间站尾部对接机构的热影响

根据空间站尾部变轨发动机和被动式对接机构的几何特点和航天器热控理论,提出一种组合系统的热分析物理、数学模型,着重研究高温变轨发动机热辐射对邻近对接机构的热影响.计算表明,2个高温变轨发动机热辐射对空间站尾部对接机构的热影响范围大致在周向角θ=(90°±30°)～(270°±30°),材料表面的发射率εd是影响对接机构组件温度的重要因素.在整个变轨期间,对接框的周向温差和最高温度已升到90℃,温度绝对增幅高达83℃,均大大超出对接机构温度的设计值,严重威胁机构部件的运动和固定功能,空间站尾部对接机构的热控措施将必不可缺.     

相变微胶囊半径及含量对织物热湿性能影响数值研究

为了指导织物内相变材料的设计,基于织物热湿耦合模型,发展了一个考虑附加相变微胶囊影响的织物内热湿传递模型．采用控制体积法和有限差分法对模型方程进行了求解．预测结果和实验数据吻合良好．基于所建模型,研究了相变微胶囊半径及含量对织物热湿性能影响．数值结果表明,在当织物温度达到相变材料（PCM）的相变温度区间时,相变材料具有延迟织物内温度变化作用．PCM半径越小延迟温度变化幅度越大,但延迟时间短．PCM含量越多延迟织物温度变化的效果越好．     

航天器热控系统的可靠性设计与分析

针对国内外航天器热控制、热管理技术的发展现状,在详细调研各种航天器热控系统组成原理与功能实现方式的基础上,从可靠性的角度出发,归纳、总结了航天器热控系统中串联、并联、表决、储备四种常见的可靠性设计模式及其相应的可靠性分析计算模型,介绍了其在空间站、月球探测系统、火星探测系统等典型航天器上的应用范例,为进一步的航天器热控系统可靠性设计方法与理论分析奠定了基础。     

激光载荷相变材料热控装置力学性能及升温特性研究

针对登月航天器激光载荷热控要求设计了一种采用十八烷作为相变材料的热控装置,使用ANSYS有限元分析软件对该装置的壳体进行了耐压强度分析,并搭建了实验装置,对该热控装置在振动条件以及真空热条件下的力学特性进行了实验研究.结果表明,在实验范围内,相变材料热控装置的壳体不会发生塑性形变和泄露.同时对其升温特性进行了实验研究,分别探讨了不同加热功率以及重力对相变材料升温特性的影响,实验结果表明,相变材料固液共存阶段比单相阶段的升温速率慢、历时长且吸收的热量多,同时,相变材料在发生相变时引起的自然对流对换热的整体效果影响可以忽略.     

相变蓄能砌体外墙中间歇通风的热过程分析

基于焓法模型,利用Fluent软件模拟分析南京地区民用建筑南外墙在夏季典型气候与太阳辐射共同作用下,绝热材料发泡聚苯乙烯(EPS)与相变材料(PCM)在三排孔砌块中不同组合时,间歇通风风速变化对室内的热影响.结果表明:相变墙外孔中为保温材料、内孔中为相变材料(构造B)在流速为2 m/s时效果最佳,在此流速下稳定后的一个周期内,室内温度波动值与热流密度相对于无机械通风分别降低了67.5％和74.04％,且温度波动平均值等于相变温度31.1℃,这样能充分发挥相变材料的作用.     

基于相变材料的锂离子电池热管理

相变材料被动式冷却利用相变材料相变时温度基本保持不变吸收或放出热量的特性,对电池组进行热管理。该冷却方式具有寄生功耗低、温度均匀性好、吸收或释放热量多等特点。但由于相变材料导热系数普遍较低,难以满足电动汽车在高电流密度工况下的电池热管理要求,从而限制了相变材料在电池热管理中的进一步应用。如何有效地提高相变材料的导热系数,同时保证其储热能力和化学稳定性,成为了研究相变材料电池热管理系统的关键问题。通过强化传热措施包括添加导热颗粒、金属翅片、泡沫金属和膨胀石墨可提高相变材料的导热系数。总结了四种强化相变材料传热的措施的研究进展,并概述了其传热措施的影响因素和强化传热效果。     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.