In this study,the permeabilities of Berea and Otway sandstones were measured under different confining pressures,and porosity was investigated through mercury intrusion porosimetry(MIP).The total porosities of the Ber...In this study,the permeabilities of Berea and Otway sandstones were measured under different confining pressures,and porosity was investigated through mercury intrusion porosimetry(MIP).The total porosities of the Berea and Otway sandstones were approximately 17.4%and 25%,respectively.Pore size distributions of each sandstone were almost the same,but the pores in the Otway sandstone were slightly narrower.However,the permeability of the Otway sandstone was smaller than that of the Berea sandstone by one order of magnitude.Three-dimensional(3D)void geometry and geometrical properties of the void spaces relevant to flow were compared to obtain the relation between the permeability differences and porosities of the two sandstones.The 3D geometrical analysis using microfocus X-ray computed tomography(CT)was performed,and the pore geometries of both sandstones were compared using the 3D medial axis(3DMA)method.Pore and throat radii,pore coordination number,tortuosity,number of connecting paths,connecting path volume,and other factors were determined using 3DMA.The Otway sandstone was characterized by a small effective throat/pore radius ratio.Based on the fluid flow mechanism,the lower effective throat/pore radius ratio results in a lower permeability induced by the fluid energy loss,which means that the 3D geometrical shape of void spaces affects the permeability value.展开更多
基于机电一体化概念设计平台MCD完成了三轴立体仓库模型的设计和仿真调试运行。首先根据“功能-行为-结构”的建模方法确定模型的基本构架为三轴立体结构,并对其进行建模和装配。其次对MCD的仿真环境进行搭建,为三轴立体仓库模型定义了...基于机电一体化概念设计平台MCD完成了三轴立体仓库模型的设计和仿真调试运行。首先根据“功能-行为-结构”的建模方法确定模型的基本构架为三轴立体结构,并对其进行建模和装配。其次对MCD的仿真环境进行搭建,为三轴立体仓库模型定义了物理及运动属性,创建位置控制及碰撞传感器,建立信号和信号适配器,搭建玩具盒搬运入库的仿真序列。最后使用TIA Portal对入库功能进行PLC编程,建立HMI的工作界面,联合MCD和TIA Portal两者进行信号的映射,通过MCD平台、 TIA Portal及高功能仿真器三者建立仿真系统,实现三轴立体仓库模型虚拟样机的机电联合调试。验证了其结构组成和控制逻辑是可行的。展开更多
The construction of new campus of Institute of Technology,Jiangxi Normal University was based on "returning to teaching",natural ecological conditions of the local area and enclosed house characterized by &q...The construction of new campus of Institute of Technology,Jiangxi Normal University was based on "returning to teaching",natural ecological conditions of the local area and enclosed house characterized by "Gan-Po culture"(culture of Jiangxi and Lake Poyang) were integrated into the design,and innovative auxiliary pedestrian roads introduced,so as to build an ecological,natural and humanistic campus with regional characteristics,multiple-level and three-dimensional development. A novel mode was given to the campus construction from a brand-new perspective.展开更多
We derive for crystal optics in coordinate-invariant way the cone approximation of refraction vectors in the neighborhood of optic axes and determine its invariants and eigenvectors. It proved to describe an elliptic ...We derive for crystal optics in coordinate-invariant way the cone approximation of refraction vectors in the neighborhood of optic axes and determine its invariants and eigenvectors. It proved to describe an elliptic cone. The second invariant of the operator of the wave equation with respect to similarity transformations determines the special cases of degeneration including the optic axes where the polarization of the waves due to self-intersection of the dispersion surface is not uniquely determined. This second invariant is included in all investigations and it is taken into account in the illustrations. It is biquadratic in the refraction vectors and the corresponding forth-order surface in three-dimensional space splits in two separate shells and a non-rational product decomposition describing this is found. We give also a more general classification of all possible solutions of an equation with an arbitrary three-dimensional operator.展开更多
基金This work was supported by the Basic Research and Development Project of the Korea Institute of Geoscience and Mineral Resources(Grant No.20-3115).
文摘In this study,the permeabilities of Berea and Otway sandstones were measured under different confining pressures,and porosity was investigated through mercury intrusion porosimetry(MIP).The total porosities of the Berea and Otway sandstones were approximately 17.4%and 25%,respectively.Pore size distributions of each sandstone were almost the same,but the pores in the Otway sandstone were slightly narrower.However,the permeability of the Otway sandstone was smaller than that of the Berea sandstone by one order of magnitude.Three-dimensional(3D)void geometry and geometrical properties of the void spaces relevant to flow were compared to obtain the relation between the permeability differences and porosities of the two sandstones.The 3D geometrical analysis using microfocus X-ray computed tomography(CT)was performed,and the pore geometries of both sandstones were compared using the 3D medial axis(3DMA)method.Pore and throat radii,pore coordination number,tortuosity,number of connecting paths,connecting path volume,and other factors were determined using 3DMA.The Otway sandstone was characterized by a small effective throat/pore radius ratio.Based on the fluid flow mechanism,the lower effective throat/pore radius ratio results in a lower permeability induced by the fluid energy loss,which means that the 3D geometrical shape of void spaces affects the permeability value.
文摘基于机电一体化概念设计平台MCD完成了三轴立体仓库模型的设计和仿真调试运行。首先根据“功能-行为-结构”的建模方法确定模型的基本构架为三轴立体结构,并对其进行建模和装配。其次对MCD的仿真环境进行搭建,为三轴立体仓库模型定义了物理及运动属性,创建位置控制及碰撞传感器,建立信号和信号适配器,搭建玩具盒搬运入库的仿真序列。最后使用TIA Portal对入库功能进行PLC编程,建立HMI的工作界面,联合MCD和TIA Portal两者进行信号的映射,通过MCD平台、 TIA Portal及高功能仿真器三者建立仿真系统,实现三轴立体仓库模型虚拟样机的机电联合调试。验证了其结构组成和控制逻辑是可行的。
基金Supported by Jiangxi Provincial Planning Program of Arts and Social Sciences(YG2012121)
文摘The construction of new campus of Institute of Technology,Jiangxi Normal University was based on "returning to teaching",natural ecological conditions of the local area and enclosed house characterized by "Gan-Po culture"(culture of Jiangxi and Lake Poyang) were integrated into the design,and innovative auxiliary pedestrian roads introduced,so as to build an ecological,natural and humanistic campus with regional characteristics,multiple-level and three-dimensional development. A novel mode was given to the campus construction from a brand-new perspective.
文摘We derive for crystal optics in coordinate-invariant way the cone approximation of refraction vectors in the neighborhood of optic axes and determine its invariants and eigenvectors. It proved to describe an elliptic cone. The second invariant of the operator of the wave equation with respect to similarity transformations determines the special cases of degeneration including the optic axes where the polarization of the waves due to self-intersection of the dispersion surface is not uniquely determined. This second invariant is included in all investigations and it is taken into account in the illustrations. It is biquadratic in the refraction vectors and the corresponding forth-order surface in three-dimensional space splits in two separate shells and a non-rational product decomposition describing this is found. We give also a more general classification of all possible solutions of an equation with an arbitrary three-dimensional operator.
