煤体变形及其瓦斯排放的相关性试验研究

通过大煤样的瓦斯排放试验研究，揭示了顺序加栽与逆序加载下的煤体变形与瓦斯排放量以及排放时间的相关性。试验结果表明：无论何种加栽方式，煤体变形与瓦斯排放量服从抛物线方程；与排放时间呈唯一对应的非线性关系。这些结论对于检测煤层瓦斯抽放率以及合理确定煤巷的维护周期具有重要的参考价值。     

瓦斯排放过程中煤体有效应力规律的实验研究

以潞安矿区3号煤层煤为样本,在实验的基础上,研究了瓦斯排放过程中煤体孔隙压力、有效应力的变化规律,揭示了煤体孔隙压力、有效应力以及等效孔隙压系数随时间的变化规律。实验结果表明,煤体的有效应力与瓦斯排放时间服从对数规律,即iσ=ailn（t）＋iσ0;煤体的等效孔隙压系数与瓦斯排放时间服从对数规律,即α=α0-cln（t）,并且在此过程中,煤体的等效孔隙压系数值是瓦斯排放时间的函数。实验结果对研究煤层中瓦斯的流动规律以及煤层气的开发具有重要的参考价值。     

考虑损伤的含瓦斯煤有效应力方程

 煤层开采和瓦斯抽放引起的煤体损伤演化不仅使煤体力学性质发生改变,而且还影响煤与瓦斯的相互作用。本文基于损伤力学与多孔介质理论,并考虑煤体吸附瓦斯膨胀变形效应,建立了压缩条件下含瓦斯煤体的有效应力方程,得到了与含瓦斯煤体损伤演化相关的孔隙压有效应力系数和吸附有效应力。利用含瓦斯煤体有效应力方程和线弹性本构模型,计算分析了不同应力条件下含瓦斯煤体的变形与有效应力系数演化特征。结果表明,计算值与试验结果一致性较好,可以有效描述含瓦斯煤体的损伤力学行为。     

安林煤矿八采区延深段水力冲孔技术研究

水力冲孔通过冲出一定量的煤炭和排放部分瓦斯,使煤体的应力降低,周围煤体得到不同程度的卸压,从而使煤体的透气性系数提高,增大了瓦斯的自然排放量和抽采量。     

煤体有效应力与膨胀应力之间关系的分析

有效应力公式是研究岩体和流体相互作用的基础公式之一,为了更加真实的描述煤体的受力状态,采用理论分析和试验分析的方法,分析了这种由于煤吸附瓦斯发生膨胀在约束条件下所产生的膨胀应力与有效应力的关系,并得出了膨胀应力与有效应力之间的关系式。分析可知,煤吸附瓦斯将发生膨胀变形,吸附量越大,膨胀变形越大,当这种变形受阻时将会产生膨胀应力膨胀应力的存在,将使煤体应力增加,煤体强度降低,煤体更易破碎,将增加煤与瓦斯突出的危险性。     

煤与瓦斯突出多因素影响规律与能量判据实验研究

为分析煤与瓦斯突出多因素耦合影响规律,开展了多组不同条件下含瓦斯煤快速揭露致突模拟试验.将模拟试验结果与突出能量模型相结合,计算突出潜能与突出耗能的定量关系,分析得出突出临界瓦斯压力与煤体强度呈正相关,与轴向应力呈负相关,验证了能量判据对突出激发的必要性.选取煤体弹性能、瓦斯膨胀能、煤体强度及密度等参数建立了两个综合考虑多影响因素的无量纲参数,进而拟合得出发生剧烈突出的能量判据公式.结果表明:瓦斯压力及轴向应力越大,煤体强度越小,突出危险性越高;各因素对煤与瓦斯突出危险性的影响重要程度排序为:瓦斯压力＞煤体强度＞轴向应力.     

含瓦斯煤体破坏过程中AE序列关联维数演化分析

利用分形理论对无瓦斯和含瓦斯煤体失稳破坏中的声发射序列关联维数演化特征进行了分析。结果表明,单轴载荷条件下煤体的声发射时间序列在各变形阶段具有明显的分形特征,各变形阶段的声发射过程具有不同的自相似性,其关联维数可描述煤样力学状态;三轴加载过程中,无瓦斯和含瓦斯煤样的声发射时间序列随应力水平的变化趋势和声发射关联维数变化趋势相似;弹性阶段后,煤样的声发射时间序列关联维数的突降,可以作为破坏的“前兆”,这一特征不随围压变化、瓦斯压力的存在与否而发生变化。     

含瓦斯煤体内多场耦合及损伤断裂机理

为了揭示含瓦斯煤体内应力场-瓦斯场-裂隙场三场之间的耦合关系及其损伤断裂机理.运用弹性力学、损伤力学及瓦斯渗流理论,通过建立损伤变量,描述煤体在有效应力作用下裂隙场的变化,同时给出损伤变量对煤体内孔隙率的影响以及煤体受损伤后有效应力的变化方程;根据所建耦合方程,考虑煤体在应力场-瓦斯场-裂隙场耦合作用下煤体内的微小变形对煤体宏观性能的影响,给出了不同损伤情况下煤体内瓦斯压力的分布规律.揭示了多场耦合作用下煤体内大量微损伤积累通过跨尺度的非线性串级发展而诱发煤体的宏观灾变,并从能量角度给出了含瓦斯煤体的损伤断裂准则.     

含瓦斯煤体非线性应力-应变模型研究

含瓦斯煤体的应力-应变本构模型是煤岩工程领域研究的一个重要课题。结合不同含水率与围压下的含瓦斯煤体应力-应变曲线发展特点,采用邓肯-张双曲线模型、指数模型以及修正的邓肯-张模型对含瓦斯煤体常规三轴压缩试验的应力-应变曲线进行了拟合,并从强度与变形特征角度展开了对比分析。研究结果表明:相对于邓肯-张模型及指数模型而言,修正的邓肯-张模型能更好地反映含瓦斯煤体强度随围压与饱和度变化的规律,破坏强度理论值与实测值的相对误差都在5%以内;模型切线模量理论值虽较实测值偏低,但作为材料变形参数设计值是偏安全的。     

吸附瓦斯对煤体渗透性影响的试验研究

在不同的围压、轴压、渗透压组合条件下,对乡宁2号焦煤100mm×100mm×200mm的大尺寸煤样进行了瓦斯气体吸附前后的渗透性试验。结果表明:乡宁2号焦煤的渗透率随体积应力呈阶段性变化规律,在加载初期,渗透率随体积应力有一定程度增加,随后开始迅速降低;在加载后期,渗透率缓慢下降;体积应力较低时,提高渗透压能在一定程度上提高煤体渗透率,但是随着体积应力的增长,这一作用效果减弱;煤体吸附瓦斯后,在相同体积应力与渗透压条件下,煤体的渗透率下降十分明显,平均降低9.14%～26.99%。     

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