双头单螺杆泵定子衬套热力耦合研究

为研究稠油热采工况下橡胶衬套的温升机理,对高温、含砂稠油工况下螺杆泵的定子橡胶衬套进行摩擦学试验。基于传热学原理,运用有限元方法对双头单螺杆泵橡胶衬套进行热力耦合研究,分析定子橡胶衬套温度场和热应力、应变的变化规律,并研究转速、过盈量、摩擦因数等因素对定子衬套热力耦合的影响。研究结果表明:考虑橡胶滞后生热作用,衬套的温度呈椭圆形分布,沿中心向外递减;衬套的温升,最大热应力和最大位移随转速、过盈量的增大而增大,随摩擦因数的增大而减小;摩擦因数对衬套的热力耦合场影响相对较小。     

气体钻井井底岩石热应力分析

为研究焦耳-汤姆逊冷却效应产生的低温气体与地层的传热现象,采用热传导和热弹性理论方法求得井底温度,建立井底岩石稳态温度和热应力分布模型,并分析井底岩石稳态和非稳态情况下温度和热应力的分布规律.结果表明:井底附近岩石存在低温区,径向热应力和由负压差产生的“拉应力”叠加之后加强了井底岩石向井眼变形的趋势,促使井底岩石破裂;井底岩石热应力随井底气体温度降低而增大,保持适当的井底温度有利于钻头破碎岩石及机械钻速提高;时间对于井底岩石热应力的影响较大,在研究井底低温问题时不可忽略其影响.     

套管-水泥环-地层耦合系统热应力理论解

根据弹性力学和热力学理论,推导了套管-水泥环-地层耦合系统的热应力和热位移理论计算公式,分析了系统热应力和热位移径向分布规律,以及套管温升、弹性模量、热膨胀系数、壁厚、水泥环与地层弹性模量和泊松比等参数对套管热应力和热位移的影响.结果表明:随着离套管中心径向距离的增加,径向热位移和热应力先增大后减小,最大值分别位于地层和套管外壁,而套管上Von Mises应力值迅速下降,最大值位于套管内壁;随着套管温升和套管、水泥环、地层弹性模量与热膨胀系数的增加,套管内壁Von Mises应力和外壁径向压力增大,其中套管参数变化对计算结果影响更明显.在进行稠油热采井套管抗挤毁强度计算时,应考虑热膨胀在套管外壁产生的径向压应力的影响.     

快充条件下18650锂离子电池热-力耦合分析

为研究锂离子电池温升所产生的热应力和形变分布,建立了快充条件下18650锂离子电池的热模型,仿真得到不同环境温度下电池的温度场分布,并在此基础上建立顺序热-力耦合模型,进一步分析电池的热应力和形变分布.结果表明:随着环境温度增加,电池最高温度增大,温差减小,充电末期电池温度稍有下降且降幅随环境温度增加而减小;最大应力值出现在电池柱面外边中间部分,最小应力分布在轴向两端;最大形变分布在电池轴向两端,最小形变出现在电池中心区域;电池的应力和形变随环境温度增加分别呈减小和增大趋势.     

抽水蓄能发电电动机温度场计算及热应力分析

针对机组日常运行时仅通过监测固定点的温度来预防热应力的破坏,无法准确监测不同部位的温升,更无法确定热应力分布来判断因应力导致的破坏情况。以南方电网广州抽水蓄能电站的一台已投运机组为例,通过温度场分析和热-结构耦合场分析计算了其电机全域温升及转子结构的应力。研究结果确定了定子和转子的温度分布情况,以及实际运行时应重点监测温升的部位;评估了转子结构整体热应力分布,并确定了峰值应力位置,为检修计划的制定提供理论依据。     

非均匀长圆柱超导体的热应力分析

用解析法研究了非均匀长圆柱超导体在冷却过程中,随着时间及位置变化的温度场以及热应力应变的分布.其中,假定杨氏模量呈现出与坐标和温度相关的指数形式变化.利用贝塞尔方程解析求解了热传导方程,得到了温度场的分布.结果表明:计算结果与实验结果相符,温度场在很短的时间内达到稳定,并最终趋于液氮温度,而剧烈变化的温度会导致较大的热应力.结果表明,径向应力先增大后减小,直至趋于热平衡状态;环向应力则表现为靠近中心处应力为拉应力,反之靠近边界处为压应力.     

球磨机静压轴承油膜温度场数值模拟与分析

针对球磨机静压轴承经常发生烧瓦现象,基于热传导理论,对静压轴承油膜建立数值分析模型,并利用有限元分析软件ANSYS,得到了油膜温度场分布.研究表明:三维数值模拟分析可以揭示轴瓦面油膜温度分布,解决实际工程中由于油膜很薄导致静压轴承内部温度场无法直接测量获得的问题.油膜产生温升主要是受到剪切及系统发热造成,使得油液粘度变小,从而造成油膜的刚度和承载力等性能的改变.温度峰值区出现在靠近油膜边界处,为防止温升过高,可采取风冷、降低轴瓦比压等措施.分析结果对深入研究静压轴承运行过程中油膜的动态变化和传热机理、优化设计方案具有十分重要意义.     

成形方法对多孔钨组织和性能的影响

研究了单向压制和冷等静压方法制备不同粉末粒度的多孔钨收缩率、组织和显微硬度的变化规律.单向压制的烧结多孔钨,从坯体底部到顶部,径向收缩率逐渐降低,显微硬度增大;经冷等静压复压成形的多孔钨,径向烧结收缩率基本相同,显微硬度分布均匀.随着粉体粒度的增大,多孔钨的密度降低,显微硬度降低.进而分析了多孔钨显微硬度的分布规律与密度及显微组织的关系.     

基于损耗实验的电主轴温度场分析

目的分析高速电主轴温度场分布情况,为研究高速电主轴温升、热变形预测提供理论依据.方法建立高速电主轴1/4三维有限元模型,基于损耗实验计算主轴电机及轴承生热率前提下分析高速电主轴温升分布情况.通过电主轴测试系统建立温升实验,测量高速电主轴外壳不同部位温升验证有限元仿真结论.结果仿真结果表明:高速电主轴稳态温度场中转子处温度最高,温度为84.4℃;高速主轴壳体最高温升出现在电主轴轴头处,温升为23℃,与实验结果相比误差为8.6%.结论通过分析温升仿真和实验得到高速主轴外壳不同部位温升不同,外壳温度变化是一个非线性变化过程,前2000s温度快速升高,2000s后温度逐步稳定.此结论为有效控制高速主轴温升,减小主轴变形及提高主轴精度提供理论基础.     

冲击载荷作用下的锻锤热力耦合分析

以用于径向锻造且由基体、过渡层、耐磨层三部分构成的材料复合锻锤为研究对象,分析瞬态热流、循环冲击载荷和热载荷导致的锻锤裂纹失效问题。通过构建热力耦合模型确定锻锤的裂纹危险区域,探讨冲击载荷、温度场与变形的传递关系,进而得到锻锤分别在冲击载荷、温度场和热力耦合作用下的应力和变形分布特征。研究结果表明,锻锤温度场分布不均匀,热影响区主要位于耐磨层工作面,温度随工作面纵向深度的增加而降低;耐磨层的机械应力远大于热应力,是产生疲劳裂纹的主要原因;锻锤变形主要是机械应力和热应力共同作用的结果,最大变形区域位于耐磨层工作面靠近预变形区一侧。仿真分析结果与锻锤实际失效情形一致,可为锻锤的优化设计提供参考。     

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.     

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.     

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.     

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.     

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.     

On Tragic Consciousness In The Works By Ernest Hemingway

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.