The paper presented a new regular pattern （network structure ） of great earthquakes occurred in China's Mainland during the past 700 years, which may be helpful to improve the understanding of great earthquakes ...The paper presented a new regular pattern （network structure ） of great earthquakes occurred in China's Mainland during the past 700 years, which may be helpful to improve the understanding of great earthquakes and can serve as a base for the study of prediction of future great earthquakes. It can be done because there are quite complete and confident records of historical and recent earthquakes in a wide extent in China.展开更多
Natural gas is widely used because it is environmentally friendly,particularly in reducing carbon emission and improving the Air Quality Index(AQI)around densely populated cities.China has initiated a coal-to-gas proj...Natural gas is widely used because it is environmentally friendly,particularly in reducing carbon emission and improving the Air Quality Index(AQI)around densely populated cities.China has initiated a coal-to-gas project(CGP)to improve the air quality in northern China.As a subcompany of China National Petroleum Corporation,PetroChina Natural Gas Marketing North Company has been focusing on natural gas resource allocation while considering numerous issues such as ensuring the bottom line of livelihood requirements in winter and the performance of economic indicators for an entire calendar year in the northern part of China.Therefore,the accurate prediction of natural gas consumption is important to PetroChina Natural Gas Marketing North Company.It has become a challenge to forecast natural gas consumption because the natural gas market has changed considerably because of the CGP.Natural gas consumption cannot be forecasted using conventional models.This study analyzes the characteristics of the CGP based on the data obtained from rural individual users and company users.Based on the analysis,the gas consumption in winter is predicted using two different forecasting approaches.The methods presented in this paper provide a basis for formulating effective measures for natural gas scheduling in the northern part of China.展开更多
In view of the seismic exploration problem of thin sand reservoirs in the Songliao Basin, this paper puts forward a migration imaging method using CGP （common geophone point） stacked cylindrical waves. By this means...In view of the seismic exploration problem of thin sand reservoirs in the Songliao Basin, this paper puts forward a migration imaging method using CGP （common geophone point） stacked cylindrical waves. By this means, seismic data should be acquired from a midpoint shooting layout system with small shot-point spacing and small geophone interval. Using such seismic data, CGP gathers are first stacked to compose a cylindrical wave section. The cylindrical wave section is migrated and imaged by means of the ray path downward continuation of the down-going wave and the wave equation downward continuation of the upgoing wave. The results from the modeling analysis and the data processing of the TK8157 seismic line in the Songliao Basin shows that the proposed migration imaging method has higher seismic resolution and fidelity. Furthermore, the proposed method is proven to be more effective for discovering small sand bodies, small faults, stratigraphic pinch-outs, and so on.展开更多
Chaotic genetic patchiness （CGP） refers to surprising patterns of spatial and temporal genetic structure observed in some marine species at a scale where genetic variation should be efficiently homogenized by gene f...Chaotic genetic patchiness （CGP） refers to surprising patterns of spatial and temporal genetic structure observed in some marine species at a scale where genetic variation should be efficiently homogenized by gene flow via larval dispersal. Here we review and discuss 4 mechanisms that could generate such unexpected patterns： selection, sweepstakes reproductive success, collective dispersal, and temporal shifts in local population dynamics. First, we review examples where genetic differentiation at specific loci was driven by diversifying selection, which was historically the first process invoked to explain CGP. Second, we turn to neutral demographic processes that may drive genome-wide effects, and whose effects on CGP may be enhanced when they act together. We discuss how sweepstakes reproductive success accelerates genetic drift and can thus generate genetic structure, provided that gene flow is not too strong. Collective dispersal is another mechanism whereby genetic structure can be maintained regardless of dispersal intensity, because it may prevent larval cohorts from becoming entirely mixed. Theoretical analyses of both the sweepstakes and the collective dispersal ideas are presented. Finally, we discuss an idea that has received less attention than the other ones just mentioned, namely temporal shifts in local population dynamics.展开更多
Constrained groove pressing(CGP)is a severe plastic deformation(SPD)technique used as a strengthening method for sheet metal.In the current work,an optimal/cost-saving design for CGP dies was attained using the stress...Constrained groove pressing(CGP)is a severe plastic deformation(SPD)technique used as a strengthening method for sheet metal.In the current work,an optimal/cost-saving design for CGP dies was attained using the stress analysis tool in SolidWorks Simulation Xpress wizard.This study examined low-cost and widely industrially applied aluminium materials,i.e.,pure 1050 Al and 5052 Al alloy.Each material was subjected to three passes of the CGP process using a 150 tons capacity press.For both materials,inter-pass annealing treatment was undertaken before the third pass.The effect of the number of CGP passes on the microstructure and tensile properties was studied after each pass.For CGPed pure 1050 Al with respect to the as-received material,the ultimate tensile strength(UTS),yield strength(YS)and YS/UTS ratio increased with an increasing number of CGP passes until the second pass,while elongation decreased with the number of passes.For CGPed 5052 Al alloy,the UTS and YS increased after the first pass and then decreased after the second pass.Variations in the elongation and YS/UTS ratio of 5052 Al alloy after the CGP process were insignificant.After inter-pass annealing and applying the third CGP pass,the strength of pure 1050 Al decreased,and that of 5052 Al alloy increased,which was attributed to the influence of composition on their structures.The strength-ductility balance decreased with an increasing number of CGP passes in both materials.展开更多
回顾了改革开放初期,经国家教育部批准的中美化学研究生项目的由来和实施情况。该项目是由美国科学院院士,著名有机化学家,哈佛大学终身教授多林(William von E.Doering)创导和联系的,由复旦大学负责具体组织工作。该项目的实施对中国...回顾了改革开放初期,经国家教育部批准的中美化学研究生项目的由来和实施情况。该项目是由美国科学院院士,著名有机化学家,哈佛大学终身教授多林(William von E.Doering)创导和联系的,由复旦大学负责具体组织工作。该项目的实施对中国化学学科的发展和人才培养产生了深远的影响。展开更多
The refinery of Yanshan Petrochemical Company has twice retrofitted a 2.0-Mt/a RFCC unit with the MIP-CGP technology aimed at maximization of isoparaffins/clean gasoline and increased output of propylene. By modifying...The refinery of Yanshan Petrochemical Company has twice retrofitted a 2.0-Mt/a RFCC unit with the MIP-CGP technology aimed at maximization of isoparaffins/clean gasoline and increased output of propylene. By modifying the riser reactor with addition of the second reaction zone coupled with an added external catalyst cooler outside the regenerator and adoption of the CGP catalyst to control the cracking depth the refiners have realized the target of reducing olefin content in gasoline and increasing the yield of LPG. The results of retrofitting the RFCC unit have revealed that after revamp of FCC unit the yield of LPG was increased by 7.31%, the conversion rate was increased by 9.06%, and the total liquid yield was decreased by 0.3%. After revamp of the RFCC unit the olefin content in gasoline was reduced by 19.5 v%, and the RON rating of gasoline was increased by 0.7 units to meet the demand of Beijing municipality for manufacture of the Olympic clean gasoline.展开更多
基金The Central Level,Scientific Research Institutes for Basic R & D Special Fund Business (No.2060302)National Natural Science Foundation of China(No.40841016,No.40372131 and No.40702056)Old Experts Science Foundation of China Earthquake Administration(No.201039)
文摘The paper presented a new regular pattern （network structure ） of great earthquakes occurred in China's Mainland during the past 700 years, which may be helpful to improve the understanding of great earthquakes and can serve as a base for the study of prediction of future great earthquakes. It can be done because there are quite complete and confident records of historical and recent earthquakes in a wide extent in China.
基金supported by the National Natural Science Foundation of China (No. 51504271)
文摘Natural gas is widely used because it is environmentally friendly,particularly in reducing carbon emission and improving the Air Quality Index(AQI)around densely populated cities.China has initiated a coal-to-gas project(CGP)to improve the air quality in northern China.As a subcompany of China National Petroleum Corporation,PetroChina Natural Gas Marketing North Company has been focusing on natural gas resource allocation while considering numerous issues such as ensuring the bottom line of livelihood requirements in winter and the performance of economic indicators for an entire calendar year in the northern part of China.Therefore,the accurate prediction of natural gas consumption is important to PetroChina Natural Gas Marketing North Company.It has become a challenge to forecast natural gas consumption because the natural gas market has changed considerably because of the CGP.Natural gas consumption cannot be forecasted using conventional models.This study analyzes the characteristics of the CGP based on the data obtained from rural individual users and company users.Based on the analysis,the gas consumption in winter is predicted using two different forecasting approaches.The methods presented in this paper provide a basis for formulating effective measures for natural gas scheduling in the northern part of China.
文摘In view of the seismic exploration problem of thin sand reservoirs in the Songliao Basin, this paper puts forward a migration imaging method using CGP （common geophone point） stacked cylindrical waves. By this means, seismic data should be acquired from a midpoint shooting layout system with small shot-point spacing and small geophone interval. Using such seismic data, CGP gathers are first stacked to compose a cylindrical wave section. The cylindrical wave section is migrated and imaged by means of the ray path downward continuation of the down-going wave and the wave equation downward continuation of the upgoing wave. The results from the modeling analysis and the data processing of the TK8157 seismic line in the Songliao Basin shows that the proposed migration imaging method has higher seismic resolution and fidelity. Furthermore, the proposed method is proven to be more effective for discovering small sand bodies, small faults, stratigraphic pinch-outs, and so on.
文摘Chaotic genetic patchiness （CGP） refers to surprising patterns of spatial and temporal genetic structure observed in some marine species at a scale where genetic variation should be efficiently homogenized by gene flow via larval dispersal. Here we review and discuss 4 mechanisms that could generate such unexpected patterns： selection, sweepstakes reproductive success, collective dispersal, and temporal shifts in local population dynamics. First, we review examples where genetic differentiation at specific loci was driven by diversifying selection, which was historically the first process invoked to explain CGP. Second, we turn to neutral demographic processes that may drive genome-wide effects, and whose effects on CGP may be enhanced when they act together. We discuss how sweepstakes reproductive success accelerates genetic drift and can thus generate genetic structure, provided that gene flow is not too strong. Collective dispersal is another mechanism whereby genetic structure can be maintained regardless of dispersal intensity, because it may prevent larval cohorts from becoming entirely mixed. Theoretical analyses of both the sweepstakes and the collective dispersal ideas are presented. Finally, we discuss an idea that has received less attention than the other ones just mentioned, namely temporal shifts in local population dynamics.
文摘Constrained groove pressing(CGP)is a severe plastic deformation(SPD)technique used as a strengthening method for sheet metal.In the current work,an optimal/cost-saving design for CGP dies was attained using the stress analysis tool in SolidWorks Simulation Xpress wizard.This study examined low-cost and widely industrially applied aluminium materials,i.e.,pure 1050 Al and 5052 Al alloy.Each material was subjected to three passes of the CGP process using a 150 tons capacity press.For both materials,inter-pass annealing treatment was undertaken before the third pass.The effect of the number of CGP passes on the microstructure and tensile properties was studied after each pass.For CGPed pure 1050 Al with respect to the as-received material,the ultimate tensile strength(UTS),yield strength(YS)and YS/UTS ratio increased with an increasing number of CGP passes until the second pass,while elongation decreased with the number of passes.For CGPed 5052 Al alloy,the UTS and YS increased after the first pass and then decreased after the second pass.Variations in the elongation and YS/UTS ratio of 5052 Al alloy after the CGP process were insignificant.After inter-pass annealing and applying the third CGP pass,the strength of pure 1050 Al decreased,and that of 5052 Al alloy increased,which was attributed to the influence of composition on their structures.The strength-ductility balance decreased with an increasing number of CGP passes in both materials.
文摘The refinery of Yanshan Petrochemical Company has twice retrofitted a 2.0-Mt/a RFCC unit with the MIP-CGP technology aimed at maximization of isoparaffins/clean gasoline and increased output of propylene. By modifying the riser reactor with addition of the second reaction zone coupled with an added external catalyst cooler outside the regenerator and adoption of the CGP catalyst to control the cracking depth the refiners have realized the target of reducing olefin content in gasoline and increasing the yield of LPG. The results of retrofitting the RFCC unit have revealed that after revamp of FCC unit the yield of LPG was increased by 7.31%, the conversion rate was increased by 9.06%, and the total liquid yield was decreased by 0.3%. After revamp of the RFCC unit the olefin content in gasoline was reduced by 19.5 v%, and the RON rating of gasoline was increased by 0.7 units to meet the demand of Beijing municipality for manufacture of the Olympic clean gasoline.
