杏花矿井下局扇双电源供电的改进

瓦斯已经是煤矿企业的最重要的自然灾害之一。而杏花矿是高瓦斯矿井,瓦斯治理尤为重要。本文通过对杏花煤矿井下局扇三专双电源供电的原理进行分析,对杏花煤矿井下局扇双电源供电进行了改进,使杏花矿井下局扇供风基本实现不间断供风,减少了井下掘进面瓦斯超限的安全隐患。     

局扇进风口元件结构形式对其噪声性能影响的试验研究

对进气部件结构形式、局扇的噪声及空气动力性能进行了试验研究，并提出了改进设计方案。试验结果表明，设计结构合理的局扇进风口部件不但可以提高局扇的空气动力性能而且可以明显地降低局扇的噪声     

谢桥矿掘进工作面局扇三路供电改造及设计

针对我国煤矿瓦斯事故高发等情况,我们在对掘进工作面通风存在的各种问题进行了分析和研究,并对掘进工作面局扇进行了三路供电安全技术改造,在"三专两闭锁"的基础上,实现了局扇"一主两备,三个局扇间的自动切换"的安全改造目标,基本杜绝了瓦斯超限事故,安全经济效益巨大。     

双三专供电方式在煤矿中的应用

近几年来煤矿瓦斯事故不断发生。瓦斯已经成为煤矿企业危害最大的自然灾害之一。而不少矿下作业都属于高瓦斯矿井,瓦斯治理尤为重要。本文通过对煤矿井下局扇双三专供电的原理进行分析和讨论,为了实现风电闭锁和瓦斯电闭锁功能,在每路风机的开关电源侧分别安装一台智能型断电仪,分别为各自的风机服务,受控于监测系统的地面中心站。每一组风机开关的常开接点与断电仪常闭接点串联形成输出的控制线路与另一组风机形成的控制线路并联,这样的话就实现了风电闭锁和瓦斯电闭锁功能。而且,为了风机的切换方便,采用了主副局扇自动切换的方式,当主局扇突然停止运转时,副局扇自动启动,且反应时间很短,从而保证了工作面的正常通风,使矿井下局扇供风基本实现不间断供风,消除了井下采掘面瓦斯超限的安全隐患,并且已经在矿下作业得到了广泛的应用。     

矿山巷道通风局扇自动化控制系统研究

该文针对矿山阶段水平巷道通风存在的实际问题，阐述了实现通风局扇自动化控制的有效途径与方法，为保证通风局扇工作安全，降低通风费用提供有益借鉴。     

煤矿局部通风机噪声机理及控制方法

分析了矿用轴流式局部通风机(简称局扇)噪声产生的机理,分析了从局扇噪声源和传播途径上噪声控制的方法,为局扇的降噪提供了参考.     

煤矿掘进巷道瓦斯智能控制系统

针对煤矿掘进巷道的局扇恒速运转问题,提出先进的模糊控制器设计方式.系统采用通风局扇智能控制和变频器,实现了瓦斯体积分数与局部通风机变频调速的模糊控制.用MATLAB智能控制工具箱进行了仿真实验,结果表明:该方法能较好地实现掘进巷道的正常通风和瓦斯排放,达到节能运行的目的.     

轴流局扇的噪声及消声器的研制

通过分析局扇噪声频谱特性,作者研制出一种双层微穿孔板消声器。在JBT-51(5.5KW)局扇上试验,结果表明,这类消声器能使局扇噪声显著降低,而且具有对局扇气动性能影响较小的优点。     

局扇烧坏原因分析及预防措施

本文介绍了梅花井煤矿长距离通风的重要性，从局扇烧坏的原因、防止局部扇烧坏措施等方面进行了分析此较，为煤矿巷道掘进生产中提高通风质量提供了保证措施。     

浅谈均压通风在火区下采煤中的应用

因为井下空区封闭不严,煤又存在自燃发火倾向,针对这种情况,对临近面可采用了单面单局扇、单面双局扇、双面双局扇采煤和回撤等多种形式的均压通风,以有效保证了回采块段的安全生产.     

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     

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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has