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1.
土壤水分运移温度效应的数值研究   总被引:2,自引:0,他引:2  
分析了土壤水分运移温度效应的机理,基于“表面张力-粘滞流理论”对“六场-相变-扩散模型”中的土水势、非饱和水力传导系数和水分扩散系数三个参数进行了改进,即考虑了它们的温度效应,继而通过对0.2 m×0.2 m的二维砂土剖面的热湿耦合运移进行了为期60 d的数值计算,通过比较原模型和改进模型的计算结果,考察了土壤水分运移温度效应的大小.计算结果表明:第10 d,20 d,30 d,40 d,50 d和60 d时,温度效应对土壤水分含量的相对影响分别为4.98%,5.57%,6.23%,6.96%,7.78%和8.7%.同时发现,土壤水分运移的温度效应在土壤表层表现得最为明显.  相似文献   

2.
运用多孔介质"七场一相变一扩散"模型(简称七场模型),结合多孔介质溶质运移理论,建立了土壤热、湿、气及盐分耦合运移的数学模型.与一般研究溶质运移的模型不同,计算模型中所涉及的变量均在模型内求解,使模型具有较好的封闭性和相对的独立性.通过数值模拟研究了土壤中的盐分上升过程,结果表明模拟盐分上升趋势与实验结果一致,但模拟精度仍有待提高.  相似文献   

3.
非饱和含湿多孔介质传热传质的渗流模型研究   总被引:9,自引:0,他引:9  
综述了非饱和含湿多孔介质传热传质模型研究的发展。从多相渗流和扩散迁移机制出发建立以温度、压力和饱和度为基本变量的实用化三参数模型。该模型由一组描述水-汽质量守恒、空气质量守恒和能量守恒的非线性偏微分方程组成。利用该模型对埋管的热过程、砂土物性测量、毛细滞后现象、回湿过程、突发高温作用下多孔介质内部的传热传质过程和冻融过程进行了研究。为了模型的进一步应用,仍需对束缚水饱和度以下毛细压力与饱和度的关系、导热系数的影响因素及其获取方法、非饱和多孔介质传热传质的边界效应和滞后效应的物理机理等方面深入研究。非饱和多孔介质中溶质的运移更是一个饶有意义的研究课题。  相似文献   

4.
提出了非饱和多孔介质热湿传输的一般数学模型,此模型引入了在非饱和多孔介质中同时发生热质交换的多种传输机制,以使质量、动量和能量方程得到改进.引用由Whitaker建立的体积平均法,讨论达西定律应用于非饱和多孔介质的限制.  相似文献   

5.
虽然原地爆破浸出采铀技术是一种经济、高效、适合我国铀矿床特点的新的开采技术,但它所引起的井下氡污染已不容忽视.根据原地爆破浸出采铀采场铀矿堆所具有的松散、破碎和非均匀的特性,将铀矿堆抽象为松散破碎射气介质,基于多孔介质中的气-液两相渗流理论和氡运移的扩散-渗流理论,建立了松散破碎射气介质中氡运移的气液两相耦合作用数学模型,并采用有限差分法求出了模型的数值解.通过数值解研究了松散破碎射气介质中气-液两相渗流状态下氡的活度浓度分布特征,为松散破碎射气介质中氡的运移状况的预测和预报,及原地破碎浸出采场氡污染的治理与控制提供了理论依据.  相似文献   

6.
多孔介质对流干燥过程数值模拟   总被引:1,自引:0,他引:1  
为研究含湿毛细孔介质干燥过程的相变现象,建立了相变的传热传质数学模型.模型中以残余饱和度将多孔介质划分为湿区与干区,湿区和干区以“蒸发界面”动态边界相互耦合.用有限差分方法对多孔介质一维干燥过程进行了计算,数值解表明:干区是等速干燥与降速干燥的分界点;干燥初期多孔介质压力升高,温度下降;随后在等速干燥段温度分布保持不变,在出现干区时再度升高.干区出现的初期,蒸发界面向多孔介质内部推进的速度较慢,在到达介质厚度10%左右时出现转折,随后推进速度加快.  相似文献   

7.
非饱和多孔介质热湿传输的一般数学模型   总被引:1,自引:2,他引:1  
提出了非饱和多孔介质热湿传输的一般数学模型,此模型引入了在非饱和多孔介质中同时发生热质交换的多种传输机制,以使质量、动量和能量方程得到改进,引用由Whitaker建立的体积平均法,讨论达西定律应用于非饱和多孔介质的限制。  相似文献   

8.
根据多孔介质的对流-辐射能量转换效应,在圆筒型管式加热炉中加装多孔介质后,使炉内温度显著升高,排烟温度明显降低.在内径为400mm的模型炉实验中,有多孔介质时的炉温比无多孔介质时的炉温升高约50~100℃,有多孔介质时的炉子热效率比无多孔介质时炉子热效率提高约10个百分点.实验结果与理论计算符合得较好.  相似文献   

9.
针对传统斯特林机加热器加热管管外出现“热点”现象,提出斯特林机的多孔介质型加热器,以提高加热管外传热平均温度。通过改进纽曼与包克附壁射流模型,提出斯特林机加热器多孔介质模型。通过本多孔介质模型下流动传热特性与Fu x.方程下的对流换热特性对比、同时分析不同流速与孔径下的加热管换热系数,验证出:在附壁效应下,多孔介质模型对碳化硅等大孔径、内部结构均匀且形状变化平滑的泡沫型多孔介质有较好的拟合特性。  相似文献   

10.
CPL蒸发器多孔芯温压变化的数值模拟   总被引:1,自引:0,他引:1  
应用二维气液两相分层饱和多孔介质模型,对蒸发器多孔芯内的传热传质过程进行了非稳态数值模拟.根据多孔芯内气液相界面移动时,内部温度场和压力场分布的计算特性,分析了系统启动和变工况运行过程中多孔芯温度和压力的变化机制。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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。  相似文献   

19.
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.  相似文献   

20.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

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