This paper emphasizes the effect of spillovers on R&D (Research and Development) level. When competing firms have spillovers to each other in R&D, cooperation will always increase fi...This paper emphasizes the effect of spillovers on R&D (Research and Development) level. When competing firms have spillovers to each other in R&D, cooperation will always increase firms' profits. Only if the positive spillover is large enough, the cooperative R&D level will be larger than the non\|cooperative R&D level. The cooperative level will be smaller than the non\|cooperative level if the positive spillover is small enough. However, the cooperative level is always smaller than the non\|cooperative level while there're negative spillovers to each other. R&D levels are the function of the spillover and will change with the spillover. The changing regularity is related to the sign of spillover and to whether they're cooperative or not. Spillovers made by the competing firms are usually different. When spillovers are small enough, the larger the spillover obtained from the other, the smaller the firm will invest in R&D; inversely, when the spillover is large enough, the larger spillovers obtains from the other, the larger the firm will invest in R&D.展开更多
Aquatic ecosystems require ecological water allocation to prevent from being damaged by natural disasters and undue exploitation. This paper discusses and estimates the ecological water requirements (EWRs) of typica...Aquatic ecosystems require ecological water allocation to prevent from being damaged by natural disasters and undue exploitation. This paper discusses and estimates the ecological water requirements (EWRs) of typical areas in the Huaihe Basin to determine rational allocations of water resources and pro- mote regional improvements of the ecological environment. The main river course, including Hongze Lake and Nansi Lake, was selected as the study subject. Calculational methods for the river and lake EWRs were based on the reasonableness of the results and data availability. The monthly guarantee rate method was used to calculate monthly, flood period, non-flood period, and annual EWRs for the main river course and the main tributaries at two different guarantee rates. The minimum water level method was used to calculate annual EWRs for Hongze Lake and the upper and lower Nansi Lake of 1.521×10^9 m^3, 0.637×10^9 m^3, and 0.306×10^9 m^3. The results were used to evaluate the rationality of the quantity of water resources allocated to ecological uses in the Huaihe Basin during 1998-2003. The result shows that the present water resource allocations in the Huaihe Basin cannot satisfy the basic ecological requirements for some years, especially years with less precipitation.展开更多
Polar ships need to meet stringent safety and environmental requirements.Usually those ships are classified by diferent ice classes based on ice operation capability.However,the polar ships are also trapped by severe ...Polar ships need to meet stringent safety and environmental requirements.Usually those ships are classified by diferent ice classes based on ice operation capability.However,the polar ships are also trapped by severe ice condition due to low propulsion power.Therefore,it is a realistic question to design the appropriate minimum propulsion power for ice operation.This paper focuses on the ice resistance and its related propulsion power for the ships with polar code(PC)classes.In consideration of seven typical polar ice conditions related to the PC rule of International Association of Classification Societies(IACS),a prediction method of ice resistance is developed by Lindqvist's model.The results are compared with those of Lindqvist's model and Riska's model by using two real ship lines.The comparison among propulsion requirements of representative classification societies is made,and a formula of minimum propulsion power is presented on the basis of ice resistance by revised Finnish-Swedish Ice Class Rules(FSICR)method.The results are verified by the actual values from seven ice class ships.A relatively good agreement is achieved.As a conclusion,the presented prediction method of ice resistance and minimum propulsion power is recommended for evaluation of ice resistance and its related propulsion power during the process of developing polar ships.展开更多
文摘This paper emphasizes the effect of spillovers on R&D (Research and Development) level. When competing firms have spillovers to each other in R&D, cooperation will always increase firms' profits. Only if the positive spillover is large enough, the cooperative R&D level will be larger than the non\|cooperative R&D level. The cooperative level will be smaller than the non\|cooperative level if the positive spillover is small enough. However, the cooperative level is always smaller than the non\|cooperative level while there're negative spillovers to each other. R&D levels are the function of the spillover and will change with the spillover. The changing regularity is related to the sign of spillover and to whether they're cooperative or not. Spillovers made by the competing firms are usually different. When spillovers are small enough, the larger the spillover obtained from the other, the smaller the firm will invest in R&D; inversely, when the spillover is large enough, the larger spillovers obtains from the other, the larger the firm will invest in R&D.
基金the National Key Basic Research and Development (973) Program of China (No. 2006CB403407)
文摘Aquatic ecosystems require ecological water allocation to prevent from being damaged by natural disasters and undue exploitation. This paper discusses and estimates the ecological water requirements (EWRs) of typical areas in the Huaihe Basin to determine rational allocations of water resources and pro- mote regional improvements of the ecological environment. The main river course, including Hongze Lake and Nansi Lake, was selected as the study subject. Calculational methods for the river and lake EWRs were based on the reasonableness of the results and data availability. The monthly guarantee rate method was used to calculate monthly, flood period, non-flood period, and annual EWRs for the main river course and the main tributaries at two different guarantee rates. The minimum water level method was used to calculate annual EWRs for Hongze Lake and the upper and lower Nansi Lake of 1.521×10^9 m^3, 0.637×10^9 m^3, and 0.306×10^9 m^3. The results were used to evaluate the rationality of the quantity of water resources allocated to ecological uses in the Huaihe Basin during 1998-2003. The result shows that the present water resource allocations in the Huaihe Basin cannot satisfy the basic ecological requirements for some years, especially years with less precipitation.
基金the National Natural Science Foun-dation of China(Nos.51809124 and 51911530156)the Natural Science Foundation of Jiangsu Province(No.BK20170576)+1 种基金the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(No.17KJB580006)the Project of State Key Lab-oratory of Ocean Engineering of Shanghai Jiao Tong University(No.1704,1807)。
文摘Polar ships need to meet stringent safety and environmental requirements.Usually those ships are classified by diferent ice classes based on ice operation capability.However,the polar ships are also trapped by severe ice condition due to low propulsion power.Therefore,it is a realistic question to design the appropriate minimum propulsion power for ice operation.This paper focuses on the ice resistance and its related propulsion power for the ships with polar code(PC)classes.In consideration of seven typical polar ice conditions related to the PC rule of International Association of Classification Societies(IACS),a prediction method of ice resistance is developed by Lindqvist's model.The results are compared with those of Lindqvist's model and Riska's model by using two real ship lines.The comparison among propulsion requirements of representative classification societies is made,and a formula of minimum propulsion power is presented on the basis of ice resistance by revised Finnish-Swedish Ice Class Rules(FSICR)method.The results are verified by the actual values from seven ice class ships.A relatively good agreement is achieved.As a conclusion,the presented prediction method of ice resistance and minimum propulsion power is recommended for evaluation of ice resistance and its related propulsion power during the process of developing polar ships.