C50高强泵送砼的研制与应用

详细介绍C50高强泵送砼采用各种常规原材料的选配，掺用ZD—18高效泵送剂可提高混凝土的早期强度，与不掺泵送剂的砼相比，掺1％泵送剂的混凝土，其硬化后的强度3天可提高49％，7天可提高43％，28天可提高26％。     

对管道泵施工和泵送混凝土骨料选择的探讨

在建设工程中，通常把可以使用混凝土泵作业，并能通过管道输送装置将提前拌合好的混凝土拌和物传送到指定的施工作业面的混凝土，称之为泵送混凝土。泵送混凝土要求具有较好的流动性，以防止混凝土拌合物在运输过程以及现场管道传输中发生离析和堵塞，因此，泵送混凝土对骨料的要求相对很严格。结合工作实际，就混凝土输送泵施工中，对泵送混凝土的骨料选择进行了阐述。     

C50高性能泵送混凝土的试验研究

为了降低配制高性能混凝土的成本，采用闽江优质江砂和蓟县产的Ⅱ类河砂混用，以及天津军粮城电厂Ⅱ级粉煤灰和唐山第三水泥厂生产的S75Ⅲ级磨细矿粉作为矿物掺合料配制C50高性能泵送混凝土，结果表明采用混用砂和选择Ⅱ级粉煤灰，S75Ⅲ级磨细矿粉的掺用对混凝土强度影响不大，反而对混凝土拌合物长距离泵送作业，混凝土拌合物坍落度经时损失，降低混凝土的水化热和早期强度要求不高的结构混凝土更为有利。     

泵送钢纤维混凝土的地面施工

阐述了泵送钢纤维混凝土地面施工的若干技术问题,包括对泵送钢纤维混凝土配合比的确定以及泵送钢纤维混凝土的生产、质量控制、运输、浇注、养护等。     

唐山地区泵送混凝土强度发展规律

通过对唐山地区泵送混凝土强度试验分析,得出了泵送混凝土在标准养护、自然养护条件下强度发展规律,给出了唐山地区泵送混凝土在同条件养护下强度等效龄期为600℃·d,强度代表值乘以强度折算系数1．052。     

浅谈泵送混凝土的施工

<正>泵送砼适用于整体砼浇筑、运输不便的砼浇筑、大体积砼浇筑。它与传统的施工方法不同,除满足设计强度、耐磨性之外,还要满足管道输送对混凝土拌和物的要求,即良好的可泵性。所谓可泵性是指混凝土拌和物能顺利通过管道,摩擦阻力小,不离析, 不堵塞和粘聚陛良好的特性。泵送混凝土对材料、     

唐山地区泵送混凝土强度发展规律

通过对唐山地区泵送混凝土强度试验分析,得出了泵送混凝土在标准养护、自然养护条件下强度发展规律,给出了唐山地区泵送混凝土在同条件养护下强度等效龄期为600℃·d,强度代表值乘以强度折算系数1.052.     

浅谈泵送砼施工应用中的注意事项

泵送混凝土是指混凝土从砼搅拌运输车或储料斗中卸人混凝土泵的料斗,利用泵的压力将混凝土沿管道直接水平或垂直输送到浇筑地点的工艺.它具有输送能力大(水平运输距离达800m,垂直运输距离达300m)、速度快、效率高、节省人力、能连续作业等特点.本论述主要介绍了砼原材料的选择,以及泵送砼的技术要求和泵送过程中的注意事项.     

环保混凝土的可泵性试验研究

在混凝土拌和物中掺入活性粉煤灰和适量的FDN-P泵送剂，两者的复合作用使混凝土的工作性得以改善，耐久性、强度得以提高，环保混凝土的可泵性得以解决。     

外加剂对混凝土早期徐变特性影响试验研究

利用自行设计的杠杆卧拉式徐变测定装置对早龄期掺外加剂混凝土进行徐变特性试验研究,研究外加剂对于混凝土早期徐变特性的影响。研究表明,缓凝、泵送混凝土增强剂对混凝土早期拉伸徐变有一定的影响,在同水灰比及水泥用量条件下,加载时混凝土强度越低,徐变越大。     

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.     

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of