Using polar equations for conic sections, we research conic circumscribed n-sided polygons（n ≥ 4） deeply on the basis of papers[1-3]. We obtain a general fixed value theorem for directed areas of some triangles in ...Using polar equations for conic sections, we research conic circumscribed n-sided polygons（n ≥ 4） deeply on the basis of papers[1-3]. We obtain a general fixed value theorem for directed areas of some triangles in conic circumscribed n-sided polygons and derive as many as n（n - 3） concurrent points of three lines and some other collinear, equiareal results in conic circumscribed n-sided polygons（n ≥ 4）. So the results of papers[1-3] are unified.展开更多
The Fe-Pb-Zn-Cu polymetallic deposits in the Luziyuan area, are of a sedimentary-reformed type related with magmatic hydrothermalism. Previous researches have suggested that the mineralization is closely related to th...The Fe-Pb-Zn-Cu polymetallic deposits in the Luziyuan area, are of a sedimentary-reformed type related with magmatic hydrothermalism. Previous researches have suggested that the mineralization is closely related to the hidden granites, but little is known about these granites including their burial depth and scale, which has limited the establishment of prospecting models and the optimization of prospecting targets. Geophysical methods have a great exploration depth, and have played a unique role in the prediction of hidden granites. It is shown that granites have low density and high resistivity,展开更多
Energy conservation and emissions reduction have become increasingly significant for automobiles due to the severity of the current energy situation.Hybrid electric vehicle(HEV)technology is one of the most promising ...Energy conservation and emissions reduction have become increasingly significant for automobiles due to the severity of the current energy situation.Hybrid electric vehicle(HEV)technology is one of the most promising solutions.This study investigated the total efficiency of a HEV powertrain.To improve the total efficiency,the engine should be regulated to work at its highest efficiency and drive the wheels directly as much as possible.To accomplish this,we developed an energy management strategy based on the direct drive area(DDA)of the engine’s efficiency map.Several typical HEV models were built to compare the fuel consumption using DDA and rule-based strategies.Furthermore,the function of the HEV transmission system with DDA was considered.The transmission in a HEV should regulate the engine to work at its highest efficiency as much as possible,which is rather different than the regulation in an internal combustion engine vehicle.The functional change may lead to transmission systems with fewer gears but optimal gear ratios.If this trend is realized,the manufacturing cost of HEVs could be largely reduced.展开更多
For radiative direct exchange areas in three dimensional system, the Uniform Deterministic Discrete Method (UDDM) was adopted. The spherical surface dividing method for sending area element and the regular icosahedron...For radiative direct exchange areas in three dimensional system, the Uniform Deterministic Discrete Method (UDDM) was adopted. The spherical surface dividing method for sending area element and the regular icosahedron for sending volume element can meet with the direct exchange area computation of any kind of zone pairs. The numerical examples of direct exchange area in three dimensional system with nonhomogeneous attenuation coefficients indicated that the UDDM can give very high numerical accuracy.展开更多
基金Foundation item： Supported by Natural Science Foundation of China（60675022）
文摘Using polar equations for conic sections, we research conic circumscribed n-sided polygons（n ≥ 4） deeply on the basis of papers[1-3]. We obtain a general fixed value theorem for directed areas of some triangles in conic circumscribed n-sided polygons and derive as many as n（n - 3） concurrent points of three lines and some other collinear, equiareal results in conic circumscribed n-sided polygons（n ≥ 4）. So the results of papers[1-3] are unified.
文摘The Fe-Pb-Zn-Cu polymetallic deposits in the Luziyuan area, are of a sedimentary-reformed type related with magmatic hydrothermalism. Previous researches have suggested that the mineralization is closely related to the hidden granites, but little is known about these granites including their burial depth and scale, which has limited the establishment of prospecting models and the optimization of prospecting targets. Geophysical methods have a great exploration depth, and have played a unique role in the prediction of hidden granites. It is shown that granites have low density and high resistivity,
基金the National Natural Science Foundation of China(71403142,71774100,71690241)Young Elite Scientists Sponsorship Program of the Chinese Association for Science andTechnology(YESS20160140)BeijingNatural Science Foundation(9162008).
文摘Energy conservation and emissions reduction have become increasingly significant for automobiles due to the severity of the current energy situation.Hybrid electric vehicle(HEV)technology is one of the most promising solutions.This study investigated the total efficiency of a HEV powertrain.To improve the total efficiency,the engine should be regulated to work at its highest efficiency and drive the wheels directly as much as possible.To accomplish this,we developed an energy management strategy based on the direct drive area(DDA)of the engine’s efficiency map.Several typical HEV models were built to compare the fuel consumption using DDA and rule-based strategies.Furthermore,the function of the HEV transmission system with DDA was considered.The transmission in a HEV should regulate the engine to work at its highest efficiency as much as possible,which is rather different than the regulation in an internal combustion engine vehicle.The functional change may lead to transmission systems with fewer gears but optimal gear ratios.If this trend is realized,the manufacturing cost of HEVs could be largely reduced.
文摘For radiative direct exchange areas in three dimensional system, the Uniform Deterministic Discrete Method (UDDM) was adopted. The spherical surface dividing method for sending area element and the regular icosahedron for sending volume element can meet with the direct exchange area computation of any kind of zone pairs. The numerical examples of direct exchange area in three dimensional system with nonhomogeneous attenuation coefficients indicated that the UDDM can give very high numerical accuracy.
