恒壁温时管内强化传热性能的Yong经济分析

通过对管内受迫对流换热过程的Ｙｏｎｇ经济分析，提出了一项管内强化传热性能评能价指标：强化前后单位传热量总传热费用比η，分析结果表明，η不仅能反映采用强化传热措施后换热能力的改善和流动阻力的增大，而且能反映出强化传热管加工制造成本的增加。     

基于Webb指标的管内强化对流换热热力性能的计算及应用

依据Ｗｅｂｂ指标,对管内强化对流换热方式下传热和流阻的综合热力性能进行了推导,得到了相同泵功和换热面积条件下,强化方式换热量与光管换热量之比与管内对流换热努塞尔数Ｎｕ和管内阻力系数λ之间的函数关系式．同理得到了相同泵功和换热量条件下换热面积之比以及相同换热量和换热面积条件下泵功之比的计算式．在此基础上,对进口轴向叶片旋流器强化管内换热的热力性能进行了评价和分析     

管内纵向涡强化换热的阻力特性

为探讨管内纵向涡强化换热的阻力特性,通过理论分析和实验研究,分析了管内雷诺数以及涡发生器的安放位置、间距、高度等参数对管内阻力的影响,得到了管内阻力的拟合公式,并列出图表进行比较分析,进而得到了管内纵向涡发生器强化传热的规律和阻力特性,结果表明：在同一雷诺数下,阻力系数随间距的变化呈一次线性关系;间距相同时,较高的发生器高度对雷诺数较大时的传热有更显著的强化效果;小于纵向涡影响区域的间距设置对于强化换热是不可取的。     

换热管传热过程的熵产分析

基于热力学第一、二定律对换热管由管内到管外的传热过程进行了熵产分析,以管内流体为基准引入了无因次熵产数并得到其计算式;讨论了管内流体雷诺数、管内外流雷诺数比值、无因次入口换热温差及无因次特征尺寸等参数对换热管传热过程不可逆性能的影响。结果表明,存在一最佳的管内流体雷诺数使无因次熵产数最小;无因次熵产数值随管外与管内流体雷诺数的比值的增大而单调递增,随无因次入口换热温差和无因次特征尺寸的增大亦近似成线性增大。结果和方法对进一步完善基本对流换热过程的热力学评价具有一定的意义,同时为换热管双侧强化传热时性能的评价提供理论基础。     

环形窄通道内流动沸腾换热及两相流型研究

实验研究了垂直向上窄缝环形管内流动沸腾换热特性和流型变化，窄缝宽度为1—2．5mm．实验结果表明，窄缝内沸腾传热有明显强化，并出现了区别于常规尺寸管内的两相流型和局部换热特性。     

旗形动态插入件宽度对圆管内油类介质对流换热的影响

探索了旗形强化传热元件宽度对管内油类介质的换热及流阻特性的影响。     

内插螺旋线管传热与阻力特性的试验研究

用插入螺旋线圈来增加管内放热系数,是一种简单和有效的强化换热方式。本文详述了作者在实验室所进行的管内螺旋线圈强化传热的实验研究情况及结果。     

超临界天然气在蛇形盘管内流动与传热的数值模拟

为了更好地研究LNG浸没燃烧式气化器管内流体的流动传热特性,建立了浸没燃烧式气化器管内高压天然气升温跨临界流动传热过程的数值模型,对其轴向与环向的流动传热特性及操作参数的影响进行相关研究,并将模拟结果与现有管内超临界流体传热的关联式进行对比。发现管内传热系数随换热管长先增大后减小,在拟临界点位置达到峰值,且弯头处出现局部传热强化;提高管内质量流量能够显著强化管内传热,但流体跨临界位置也会相对延后;提高管程入口温度和水浴温度均使流体跨临界位置提前,而较高的水浴温度会使传热系数峰值偏低;模拟结果与现有传热关联式的对比结果发现,JacksonHall公式更能准确预测超临界天然气在蛇形盘管内的传热特性,但不能体现弯头处的局部传热强化。研究结果为浸没燃烧式气化器的设计工作提供了依据。     

高压直流电场强化垂直管内沸腾传热试验研究

在分离式热管结构的电水动力学（EHD）强化传热试验台上,采用R11工质、直流高压电场,首次完成了垂直管内沸腾换热的EHD强化试验研究,结果表明：采用EHD技术对垂直管内的沸腾换热有明显的强化效果;低热流密度时,强化效果较好,增大热流密度时,强化效果减弱;当热 流密度维持不变时,强化系数随着电场电压的增大而增大;沸腾换热的最大强化系数为428％。     

绕花丝内插物强化凝结换热实验研究

为了提高管壳式换热器的性能，提出了一种新型管内强化传热技术——绕花丝内插物．对绕花丝内插物的强化换热机理进行了理论分析，建立了绕花丝强化管内凝结换热理论模型，并进行了实验研究．绕花丝内插物可使流体在流动方向上做复杂的三维混合流动，提前诱发湍流发生．研究结果表明，管内插入绕花丝后可使换热量在低温差下出现“陡然”上升现象，提前进入湍流状态，换热量强化比高达3-4倍，而压降相对较低，是光管的2倍左右，此外，将理论计算值与实验数据进行了比较，两者符合得很好，验证了理论模型的正确性和实用性．与其它内插物进行比较，绕花丝内插物不仅强化换热效果好，而且产生压降小。     

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.     

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.     

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.     

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.     

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。     

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.     

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that