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综放采场围岩支承压力分布及动力灾害的层厚效应 被引量:50
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作者 谢广祥 杨科 +1 位作者 常聚才 王磊 《煤炭学报》 EI CAS CSCD 北大核心 2006年第6期731-735,共5页
以谢桥矿1151(3)综放工作面地质及开采技术条件为背景,采用大型非线性三维计算机数值模拟,对不同开采高度(3.0,5.4,8.0,12.0 m)进行模拟研究.研究表明:不同采高工作面围岩支承压力分布规律存在明显差异,随着煤层一次采高的增加,工作面... 以谢桥矿1151(3)综放工作面地质及开采技术条件为背景,采用大型非线性三维计算机数值模拟,对不同开采高度(3.0,5.4,8.0,12.0 m)进行模拟研究.研究表明:不同采高工作面围岩支承压力分布规律存在明显差异,随着煤层一次采高的增加,工作面煤体内和采空侧煤柱内支承压力峰值呈下降趋势,峰值位置超前工作面距离增大,煤体抵抗损伤应变能的区域变大;工作面侧向实体煤支承压力峰值沿走向在工作面前方与煤层厚度无明显关系,而在工作面后方随采高逐渐降低,峰值位置离煤壁也越远.应用损伤力学和能量法分析了支承压力分布对煤与瓦斯突出层厚效应影响规律,表明综放开采随一次开采高度的增加,采场周围煤岩体内积聚的弹性能降低且抵抗损伤变形的能力增强,有利于减缓动力灾害. 展开更多
关键词 综放开采 支承压力 动力灾害 层厚效应
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非对称综放开采煤层三维应力分布特征及其层厚效应研究 被引量:16
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作者 谢广祥 杨科 常聚才 《岩石力学与工程学报》 EI CAS CSCD 北大核心 2007年第4期775-779,共5页
基于非对称综放开采布置特点,以谢桥煤矿1151(3)综放面地质技术条件为背景,采用计算机数值模拟,并结合现场实测研究,揭示非对称开采煤层三维应力分布及一次开采煤厚变化对应力分布的影响规律。研究结果表明,非对称开采工作面煤层应力呈... 基于非对称综放开采布置特点,以谢桥煤矿1151(3)综放面地质技术条件为背景,采用计算机数值模拟,并结合现场实测研究,揭示非对称开采煤层三维应力分布及一次开采煤厚变化对应力分布的影响规律。研究结果表明,非对称开采工作面煤层应力呈非对称分布,煤柱侧工作面煤层应力峰值及其超前距离和应力降低区的范围最大;随一次开采煤厚的增加,煤层应力峰值降低,峰值距煤壁的距离增大,应力向煤层深部煤体转移。研究为煤柱合理留设、巷道合理布置、采场围岩稳定性控制、提高煤炭资源采出率、安全高效开采等方面提供理论依据。 展开更多
关键词 采矿工程 非对称 综放开采 三维应力 层厚效应
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Oxide Thickness Effects on n-MOSFETs Under On-State Hot-Carrier Stress
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作者 胡靖 穆甫臣 +1 位作者 许铭真 谭长华 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第3期290-295,共6页
Hot carrier induced (HCI) degradation of surface channel n MOSFETs with different oxide thicknesses is investigated under maximum substrate current condition.Results show that the key parameters m and n of H... Hot carrier induced (HCI) degradation of surface channel n MOSFETs with different oxide thicknesses is investigated under maximum substrate current condition.Results show that the key parameters m and n of Hu's lifetime prediction model have a close relationship with oxide thickness.Furthermore,a linear relationship is found between m and n .Based on this result,the lifetime prediction model can be expended to the device with thinner oxides. 展开更多
关键词 HCI hot carrier effect oxide thickness effect lifetime prediction model device reliability
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Arch structure effect of the coal gangue flow of the fully mechanized caving in special thick coal seam and its impact on the loss of top coal 被引量:9
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作者 Zhang Ningbo Liu Changyou 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第4期593-599,共7页
Based on the characteristics of the top coal thickness of the fully mechanized caving in special thick coal seam,the long distance of coal gangue caving,as well as the different sizes of the coal gangue broken fragmen... Based on the characteristics of the top coal thickness of the fully mechanized caving in special thick coal seam,the long distance of coal gangue caving,as well as the different sizes of the coal gangue broken fragment dimension and spatial variation of drop flow,this paper uses laboratory dispersion simulation experiment and theoretical analysis to study the arch structure effect and its influence rule on the top coal loss in the process of coal gangue flow.Research shows that in the process of coal gangue flow,arch structure can be formed in three types:the lower arch structure,middle arch structure,and upper arch structure.Moreover,the arch structure has the characteristics of dynamic random arch,the formation probability of dynamic random arch with different layers is not the same,dynamic random arch caused the reduction of the top coal fluency;analyzing the dynamic random arch formation mechanism,influencing factors,and the conditions of instability;the formation probability of the lower arch structure is the highest,the whole coal arch and the coal gangue arch structure has the greatest impact on top coal loss.Therefore,to prevent or reduce the formation of lower whole coal arch structure,the lower coal gangue arch structure and the middle whole coal arch structure is the key to reduce the top coal loss.The research conclusion provides theoretical basis for the further improvement of the top coal recovery rate of the fully mechanized caving in extra thick coal seam. 展开更多
关键词 Extra thick coal seam Coalgangue flow Top coalloss Dynamic random arch effect
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Effects of Density and Thickness of Interlayer on RT Instability of Interfaces 被引量:1
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作者 程涛 刘升贵 +3 位作者 刘晓旸 郝耐 滕爱萍 李英骏 《Communications in Theoretical Physics》 SCIE CAS CSCD 2014年第5期649-653,共5页
This work focuses on the characteristics of the Rayleigh-Taylor Instability (RTI) of the interfaces formed by two semi-infinitely distributed fluids and one interlayer. In consideration of the coupling effects betwe... This work focuses on the characteristics of the Rayleigh-Taylor Instability (RTI) of the interfaces formed by two semi-infinitely distributed fluids and one interlayer. In consideration of the coupling effects between the interfaces, the expression of the growth rate is obtained. The result reveals that the instability growth rate depends on the density and thickness of the interlayer. It is found that /f the interlayer thickness is less than 0.6 times of the disturbing wavelength, the coupling effects should be considered. 展开更多
关键词 plasma INSTABILITY interface coupling
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Is quantum capacitance in graphene a potential hurdle for device scaling?
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作者 Jaeho Lee Hyun-Jong Chung +6 位作者 David H. Seo Jaehong Lee Hyungcheol Shin Sunae Seo Seongjun Park Sungwoo Hwang Kinam Kim 《Nano Research》 SCIE EI CAS CSCD 2014年第4期453-461,共9页
Transistor size is constantly being reduced to improve performance as well as power consumption. For the channel length to be reduced, the corresponding gate dielectric thickness should also be reduced. Unfortunately,... Transistor size is constantly being reduced to improve performance as well as power consumption. For the channel length to be reduced, the corresponding gate dielectric thickness should also be reduced. Unfortunately, graphene devices are more complicated due to an extra capacitance called quantum capacitance (CQ) which limits the effective gate dielectric reduction. In this work, we analyzed the effect of CQ on device-scaling issues by extracting it from scaling of the channel length of devices. In contrast to previous reports for metal-insulator- metal structures, a practical device structure was used in conjunction with direct radio-frequency field-effect transistor measurements to describe the graphene channels. In order to precisely extract device parameters, we reassessed the equivalent circuit, and concluded that the on-state model should in fact be used. By careful consideration of the underlap region, our device modeling was shown to be in good agreement with the experimental data. CQ contributions to equivalent oxide thickness were analyzed in detail for varying impurity concentrations in graphene. Finally, we were able to demonstrate that despite contributions from CQ, graphene's high mobility and low-voltage operation allows for ~raphene channels suitable for next generation transistors. 展开更多
关键词 GRAPHENE equivalent circuit quantum capacitance intrinsic delay
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