利用瞬态法提取岩样非Darcy流渗透特性

建立了一种测定岩样非Darcy流渗透特性试验系统的动力学模型.基于岩样两端孔隙压差的时间序列,利用差分计算或曲线拟合得到渗流速度及其变化率的时间序列.通过线性回归,得到岩样的Forchheimer非Darcy流渗透特性,即渗透率、非Darcy流β因子和加速度系数.试验结果表明,无论岩样处于峰前还是峰后应力状态,岩样中的渗流都不服从Darcy定律;当非Darcy流β因子为正时,非Darcy流的渗透率κ小于Darcy流的渗透率κD;渗透率(κ和κD)、非Darcy流β因子和加速度系数可近似表示为应变的幂指数函数;三种渗透特性中的每两种整体上存在幂指数关系;在加载的初始阶段,由于孔隙和微裂隙的压缩和闭合,渗透率随应变减小,而非Darcy流β因子和加速度系数随应变增大;随后,由于裂隙的扩展,岩样的渗透率迅速增大,而非Darcy流β因子和加速度系数迅速减小,并在峰值应力附近达各自的极值;由于围压的作用,峰后应力状态下岩样的渗透特性随应变的变化缓慢.图3,参18.     

深埋高围压高水压下低渗透岩石的渗透特性

为了探讨深埋高围压条件下低渗透岩石的渗透特性,取锦屏二级水电站大理岩试样分别进行不同围压条件下全应力—应变过程渗流试验。根据试验结果分析得出:岩石渗透系数变化与体积变形密切相关。因此,采用变形相关的渗透系数来研究岩石在破坏前后不同阶段的渗透系数与体积应变的关系。对于低渗透岩石,在峰前阶段渗透系数变化不明显,峰后破坏阶段渗透系数显著增大。高围压使岩石破坏延迟,岩石峰前阶段的低渗透特性表现的更持久。用变形相关的渗透系数模拟岩体流—固耦合问题更符合实际工程。     

破碎岩石非Darcy流的渗透特性试验研究

一种破碎岩石渗透特性试验专用装置与MTS试验系统结合，可以获得非Darcy流的渗透特性(渗透率和非Darcy流β因子)。介绍该装置的构造、破碎岩石非Darcy流的渗透特性试验方法和特点，得到破碎岩石压实过程中渗透特性与载荷、颗粒直径的回归关系及在某一特定载荷作用下，渗透特性ρβ与破碎岩石颗粒直径成线性关系的结果。这种试验技术对于采矿、土木、水利和交通工程具有重要的实际意义。     

高瓦斯矿煤样非Darcy流的MTS渗透性试验

为了获得某高瓦斯矿煤岩非Darcy流渗透特性,从该矿采集煤样,制作成标准煤样.利用MTS815-02型岩石力学试验系统采用全程位移控制进行了全应力应变过程数控瞬态渗透法试验,计算出了在4MPa围压,15MPa/m孔压时,煤样在不同应变下非Darcy流渗透率、非Darcy流β因子、加速度系数及渗流稳定性指数,并给出了发生渗流失稳所需的压力梯度.研究表明:该煤样具有较强的脆性,在应变保持过程中表现出较大的松弛性能;在全应力应变过程中,该煤样的峰值应力前渗透率比较低,峰值应力后渗透率增大幅度很大;在应变增大过程中,煤样非Darcy流β因子几乎均为负值;煤样的渗流稳定性指数χ的负值只出现在峰值应力后.其渗流失稳灾害表现为瓦斯从煤岩体裂隙涌出甚至发生瓦斯喷出.图5,表1,参8.     

三维应力下破碎砂岩渗透特性试验研究

承压破碎岩体中非稳态渗流是引起多种动力灾害发生的重要因素之一。利用自主研发的破碎岩石三轴渗透试验系统,考虑围压挤出的渗透液总量对碎石孔隙度的影响,进行了三维应力下5~10 mm粒径破碎砂岩的渗透试验,得到了不同轴向压缩位移、不同围压下试样的渗透特性变化规律。结果表明:不同轴向位移下,试样孔隙度随围压的升高呈对数减小,其渗透率随围压的变化逐渐减小,且各自差异性逐渐缩小;同一围压下,随轴向压缩位移增加,孔隙度、渗透率逐渐趋于一个稳定值,其中渗透率量级在10-11~10-13m2之间,表现为试样的孔隙连通性减弱,整体结构趋于稳定;非Darcy流β因子随围压的增加呈非线性增长,其中非Darcy流β因子的量级在108~1011m-1之间,试样原有级配改变明显,非Darcy流β因子增长趋势受有效毛细管数目及其孔径大小的影响,毛细管孔径减小导致渗透液与毛细管壁的相对接触面积增加。该试验结果为可控围压下破碎岩石中的渗流研究提供参考。     

气体渗流系统的失稳及其概率应用

为研究煤体受采动作用后,其渗透特性的变化。采用一种专利装置与MTS815．02型岩石力学试验系统相结合,得到峰后煤样在各种应变下的渗透特性（渗透率和非Darcy流β因子）及统计指标（均值和均方差）。对煤矿瓦斯突出发生的概率进行计算和分析。试验研究表明。煤的渗透特性不是确定的,而是服从某种分布的随机变量,瓦斯突出是否发生具有随机性,随着煤体应变的增加,瓦斯突出发生的概率迅速增加。     

突出矿煤岩微孔隙特征及其渗透特性

从煤与瓦斯突出矿采集煤样,通过扫描电镜对其微结构和孔隙裂隙特征进行了观测。利用MTS815.02型岩石力学实验系统进行了3块标准煤样全应力应变过程的电液伺服试验,给出了主应力差、煤样渗透率、非Darcy流β因子和加速度系数与轴向应变关系曲线。研究表明:该突出矿煤样结构不均一,以粒状、网状、片状结构为主,也可见到鳞片状和压扭性结构;在煤样破坏过程中,由于围压的作用,全应力应变过程中煤样的渗透率随着应变的增大而发生变化,但其变化不很显著;非Darcy流β因子和加速度系数趋势相同,非Darcy流β因子均为负值。     

某突出矿煤岩非Darcy流渗流稳定性实验研究

为了获得煤岩非Darcy流渗透特性,利用MTS-02型岩石力学试验系统采用全程位移控制对煤与瓦斯突出矿煤样进行了全应力应变过程数控瞬态渗透法试验。计算出煤样破坏过程中不同应变下非Darcy流渗透率、非Darcy流β因子、加速度系数及渗流稳定性指数,并给出发生渗流失稳所需的压力梯度。研究表明:该突出矿煤样的渗流稳定性指数χ的负值较多出现在峰值应力后并且其发生渗流失稳所需的压力梯度较大。     

变围压条件下低渗砂岩储层渗透率变化规律研究

试验研究了低渗透砂岩储层岩石的围压 -渗透率关系和围压 -松弛循环 -渗透率关系 ,试验结果表明 :随围压增加岩石的孔隙结构和骨架结构发生变化 ,引起岩石渗透率的下降 .通过对变围压条件下低渗透岩石渗透率变化规律分析 ,找到了一种新的表征围压 -渗透率关系的公式——指数函数线性组合 ,对 5个低渗透区块的 3 1组岩石样品试验数据进行对比和验证 ,该指数函数线性组合的拟合误差在± 5 %以内     

混合破碎岩样渗透特性试验研究

为研究混合破碎岩体内流体渗透规律,利用一套由液压泵、渗透仪以及DDL 600电子万能试验机等构成的破碎岩样渗透试验系统进行了混合破碎岩样渗透特性测定,分析了混合破碎岩样与单种破碎岩样渗透特性的差异.研究表明:混合破碎岩样较单种破碎岩样的非Darcy流特性更显著;随着孔隙度的增加,单种岩样较混合岩样渗透率的变化幅度大,且相同粒径不同岩性岩样的渗透率变化程度和变化趋势呈现较大差异;随着孔隙度的增加,混合岩样的非Darcy流β因子显现减小趋势,且混合岩样较其单种岩样非Darcy流β因子的大小因粒径不同而不同.     

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.     

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     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with