配置高强钢筋混凝土梁抗弯刚度的研究

随着高强钢筋的使用,混凝土梁的变形计算和控制显得更为重要.为了研究配置HRB500级高强钢筋混凝土梁的变形性能,对28根配置500MPa钢筋的混凝土梁进行了受弯刚度试验和分析,研究结果表明,现行国家混凝土规范GB 50010-2002刚度计算公式和作者提出公式与试验值吻合较好,适用于配置高强钢筋的混凝土梁变形计算.结合本次试验数据,对国内各规范的刚度计算方法进行了比较研究,并对影响刚度的主要因素进行了分析,提出了刚度计算公式进一步简化的建议.     

高强钢筋高强混凝土预应力梁短期刚度研究

通过对12根足尺高强钢筋高强混凝土预应力梁的抗弯性能试验,分析了现有规范刚度计算公式的适用性以及换算配筋率、混凝土强度等级等因素对梁短期刚度的影响.研究结果表明,梁的短期刚度随换算配筋率的增大、混凝土强度等级的提高而增强;中美混凝土规范刚度计算公式对于高强钢筋高强混凝土预应力梁仍然适用.试验研究结果可为高强钢筋高强混凝土预应力梁在实际工程中的应用提供参考依据.     

考虑预应力筋拉应变滞后的混凝土梁刚度统一

根据裂缝间钢筋平均应变符合平截面假定,分别考虑预应力筋与非预应力筋处于相同和不同水平位置处,详细推导了裂缝截面处后张有黏结预应力筋的拉应变滞后系数.结合前期完成的刚度计算规范比较结果,借鉴精度较好的刚度计算模式,并通过大量挠度试验数据,提出了考虑预应力筋拉应变滞后特点的混凝土梁刚度计算公式.结果表明:不论对钢筋混凝土梁,还是对各类预应力混凝土梁,该刚度公式计算值与实测值均符合较好,从而将钢筋混凝土梁和预应力混凝土梁的刚度公式统一起来;特别是对后张有黏结和无黏结预应力混凝土梁,相比现行混凝土结构设计规范刚度公式,该刚度公式计算精度更高,可为规范修订提供参考.     

高强钢筋高强混凝土梁刚度的试验研究

通过对高强钢筋高强混凝土梁和普通钢筋高强混凝土梁的试验研究，探讨了其受力变形特点，提出了高强钢筋高强混凝土梁的刚度计算方法和一系列计算公式，计算结果与试验结果符合较好     

非对称配置型钢混凝土T型梁变形性能

通过对非对称配置型钢混凝土T型梁的受力和变形分析,推出非对称配置的型钢混凝土T型梁的短期刚度计算公式.公式由三部分组成,每一部分的物理意义明确,容易理解.实际试验结果与公式计算结果吻合较好.且该公式可以退化为对称配置的型钢混凝土梁和钢筋混凝土梁的短期刚度计算公式,具有广泛的使用价值.     

高强钢筋混凝土梁刚度的试验研究

通过对高强钢筋高强混凝土梁和普通钢筋高强混凝土梁的试验探讨，探讨了其受力变形特点，提出了高强钢筋高强混凝土梁的刚度计算方法一系列计算公式，计算结果与试验结果符合较好。     

高强钢筋高强混凝土预应力梁抗弯性能试验研究

通过对12根高强钢筋高强混凝土预应力梁的抗弯试验,观测试验梁的破坏现象和失效过程,研究混凝土强度等级、非预应力高强钢筋配筋率、预应力钢筋配筋率等因素对其抗弯性能的影响规律.试验结果表明,高强钢筋高强混凝土预应力适筋梁破坏过程包括开裂前阶段、带裂缝工作阶段和钢筋屈服后直至失效3个阶段,各阶段破坏模式与普通钢筋混凝土梁受弯破坏相似,均为延性破坏.混凝土强度等级以影响钢筋屈服后的抗弯性能为主,高强度等级混凝土试验梁的后期承载力下降较小.非预应力筋配筋率显著影响试验梁开裂后的抗弯性能,即相同变形时,配筋率越高承载力越高.相同张拉控制应力条件下,预应力筋配筋率越高开裂弯矩越大;相同弯矩作用下,预应力配筋率越高变形越小,其极限承载力也越高.     

无黏结预应力混凝土梁短期裂缝试验

通过八根无黏结预应力混凝土梁和两根普通混凝土梁的短期裂缝试验,研究了配置HRBF500钢筋的无黏结预应力混凝土梁的裂缝间距和宽度,并对"混凝土结构设计规范GB50010—2010";裂缝计算公式的适用性进行了评析.研究表明:规范GB50010的裂缝计算模式对配HRBF500钢筋的无黏结预应力混凝土梁仍适用,但按规范GB50010计算的平均裂缝宽度和最大裂缝宽度总体上比试验值偏大,计算值与试验值之比平均分别为1.333和1.403.根据试验结果,建议将裂缝间混凝土伸长对裂缝宽度的影响系数αc和短期裂缝宽度扩大系数τs调整为0.58和1.54,调整后的计算值与试验值符合较好.     

非对称配置型钢混凝土T型梁变形性能

通过对非对称配置型钢混凝土T型梁的受力和变形分析，推出非对称配置的型钢混凝土T型梁的短期刚度计算公式。公式由三部分组成，每一部分的物理意义明确，容易理解。实际试验结果与公式计算结果吻合较好。且该公式可以退化为对称配置的型钢混凝土梁和钢筋混凝土梁的短期刚度计算公式，具有广泛的使用价值。     

高性能预应力混凝土梁挠度试验与计算方法

进行了配有高强度低松弛钢绞线、预应力比率0.66～1.00、混凝土强度等级C40～C80的14根先张法高性能预应力混凝土梁的加载全过程试验,研究了预应力比率和截面开裂等因素对试验梁挠度的影响.通过将试验结果与《混凝土结构设计规范》(GB50010—2002)相关计算公式对比分析,得出规范变形计算公式对于未开裂梁是适用的,对于预应力比率不大于0.66的梁开裂后也是适用的;随着预应力比率提高,开裂后梁挠度试验值与规范公式计算值的比值逐渐减小,当预应力比率1.00时其比值仅为0.60.为此,根据试验结果提出了适用于这种高性能预应力混凝土梁的修正的挠度计算方法.     

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the