A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the ...A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the vibrated velocity in the stern plate and main engine foundations is tested during the trial trip. Then, the excited force of the propeller and main engine is derived using the vibrated velocity and admittance matrix.Based on the excited force, the cabin-simulated vibrated velocity is compared with the tested vibrated velocity, and the tolerance is within the allowable scope in engineering. Loading the excited forces on the boundary element model, the distribution characteristics of sound level underwater are analyzed. Then, forces excited by the main engine and propeller are loaded on the model, and the contribution ratio of excitation sources to underwater acoustic radiation is analyzed. The result provides a reference for vibration assessment in the early stage and control in the late stage.展开更多
An indoor thermal environment is affected by various heat elements,such as heat transfer through walls,solar radiation,and heat emissions from people,lighting and equipment.To promote both local thermal comfort and bu...An indoor thermal environment is affected by various heat elements,such as heat transfer through walls,solar radiation,and heat emissions from people,lighting and equipment.To promote both local thermal comfort and building energy efficiency,demand-oriented ventilation(such as personalized ventilation)has been developed.When using this method,a good understanding on indoor temperature distribution becomes necessary.For this purpose,an index known as Contribution Ratio of Indoor Climate(CRI)has been developed through extraction from the calculation results of Computational Fluid Dynamics(CFD).This index can be used to analyze the independent contribution of each heat element to indoor temperature distribution.In this paper,a complete and detailed introduction of the CRI is given,including its basic premises,definitions,and mathematical meaning.Particularly,calculation method of the CRI in natural convection airflow fields is further developed.Two cases(forced and natural convection airflow fields)have been carried out in different scenarios,with results showing that the CRI of a heat source had higher values in the area around itself.Also,it had a larger influence range in forced convection airflow field because of the convective airflow,while relatively larger CRI values only appear in the area above the heat source in the natural convection airflow field because of the heat plume.As a useful index for understanding the form of indoor temperature field,the CRI has guiding significance for regulating air-conditioning/ventilation systems to build better indoor thermal environment.展开更多
Scientific and technical progress has been the driving forces of enterprises development.Milk productive enterprises are developing faster and growing better.It is very important to measure the contributive ratio of s...Scientific and technical progress has been the driving forces of enterprises development.Milk productive enterprises are developing faster and growing better.It is very important to measure the contributive ratio of scientific and technical progress in milk productive enterprises.And the appraisement could help to develop milk productive enterprises.The model C^2GS^2 was established to appraise the contributive ratio of scientific and technical progress in milk productive enterprises in the research.And the appraisement on the contributive ratio of scientific and technical progress in milk productive enterprises was made by the model.In the results of appraisement,science and technology play a main role in milk productive enterprises.It is shown that our milk productive enterprises are developed by scientific and technical progress while not by input of productive factors.展开更多
To stimulate economic growth,the Chinese government implemented three consecutive policies between 2016 and 2019 to reduce the corporate endowment insurance contribution ratio(CEICR),the highest payment item for Chine...To stimulate economic growth,the Chinese government implemented three consecutive policies between 2016 and 2019 to reduce the corporate endowment insurance contribution ratio(CEICR),the highest payment item for Chinese companies.Using China's CEICR reduction policies as a quasi-natural experiment,this paper evaluates the impact of corporate payment burden reduction on employee wages.Generally,reducing CEICR appears to prompt companies to increase employee wages.Corporate cash flow is a possible channel of influence.Moreover,the positive effect is found to be more pronounced in companies that are more labor intensive,performing better in labor payment compliance,and located in regions with higher pressure for elderly care.This paper offers evidence in favor of implementing CEICR reduction policies from the perspective of improving the well-being of employees.展开更多
China is the largest producer and consumer of vegetables,its vegetable industry is playing an important role in the domestic agricultural sector and global vegetable export market.It is important to promote the long-t...China is the largest producer and consumer of vegetables,its vegetable industry is playing an important role in the domestic agricultural sector and global vegetable export market.It is important to promote the long-term sustainable development of Chinese vegetable industry for food security and quality of people’s lives.To find out the intrinsic way to promote the development of Chinese vegetable industry,this paper analyzed the influencing factors of Chinese vegetable production by utilizing the LMDI method and demonstrated the spatial-temporal characteristics of vegetable production through application of the Arc-GIS spatial autocorrelation analysis method.The results showed that the influencing factors of vegetable production were the cultivated land area,multiple cropping index,vegetable planting proportion and vegetable yield per hectare in China.The major driving factor had changed from vegetable planting proportion to vegetable yield per hectare.The influencing degrees of factors on vegetable production are different in different regions,regionalization is therefore a major feature of Chinese vegetable production.The government should take production technology,regionalization-driven effect,and marketing integration into consideration to promote the development of Chinese vegetable industry.展开更多
文摘A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the vibrated velocity in the stern plate and main engine foundations is tested during the trial trip. Then, the excited force of the propeller and main engine is derived using the vibrated velocity and admittance matrix.Based on the excited force, the cabin-simulated vibrated velocity is compared with the tested vibrated velocity, and the tolerance is within the allowable scope in engineering. Loading the excited forces on the boundary element model, the distribution characteristics of sound level underwater are analyzed. Then, forces excited by the main engine and propeller are loaded on the model, and the contribution ratio of excitation sources to underwater acoustic radiation is analyzed. The result provides a reference for vibration assessment in the early stage and control in the late stage.
基金The authors gratefully acknowledge the coordinated support from the Natural Science Foundation of China(Grant No.5190080465)This research was also supported by the joint research project of the Wind Engineering Research Center,Tokyo Polytechnic University.(MEXT(Japan)Promotion of Distinctive Joint Research Center Program Grant Number:JPMXP0619217840,JURC grant number 20202007).
文摘An indoor thermal environment is affected by various heat elements,such as heat transfer through walls,solar radiation,and heat emissions from people,lighting and equipment.To promote both local thermal comfort and building energy efficiency,demand-oriented ventilation(such as personalized ventilation)has been developed.When using this method,a good understanding on indoor temperature distribution becomes necessary.For this purpose,an index known as Contribution Ratio of Indoor Climate(CRI)has been developed through extraction from the calculation results of Computational Fluid Dynamics(CFD).This index can be used to analyze the independent contribution of each heat element to indoor temperature distribution.In this paper,a complete and detailed introduction of the CRI is given,including its basic premises,definitions,and mathematical meaning.Particularly,calculation method of the CRI in natural convection airflow fields is further developed.Two cases(forced and natural convection airflow fields)have been carried out in different scenarios,with results showing that the CRI of a heat source had higher values in the area around itself.Also,it had a larger influence range in forced convection airflow field because of the convective airflow,while relatively larger CRI values only appear in the area above the heat source in the natural convection airflow field because of the heat plume.As a useful index for understanding the form of indoor temperature field,the CRI has guiding significance for regulating air-conditioning/ventilation systems to build better indoor thermal environment.
基金Supported by Fund of Post Doctoral Research in Heilongjiang Province(LSZH-04052)Fund of Scientific and Technical Research Projects(10551039)
文摘Scientific and technical progress has been the driving forces of enterprises development.Milk productive enterprises are developing faster and growing better.It is very important to measure the contributive ratio of scientific and technical progress in milk productive enterprises.And the appraisement could help to develop milk productive enterprises.The model C^2GS^2 was established to appraise the contributive ratio of scientific and technical progress in milk productive enterprises in the research.And the appraisement on the contributive ratio of scientific and technical progress in milk productive enterprises was made by the model.In the results of appraisement,science and technology play a main role in milk productive enterprises.It is shown that our milk productive enterprises are developed by scientific and technical progress while not by input of productive factors.
基金grateful to anonymous referees for their very helpful comments and suggestions,which significantly improved the paper.
文摘To stimulate economic growth,the Chinese government implemented three consecutive policies between 2016 and 2019 to reduce the corporate endowment insurance contribution ratio(CEICR),the highest payment item for Chinese companies.Using China's CEICR reduction policies as a quasi-natural experiment,this paper evaluates the impact of corporate payment burden reduction on employee wages.Generally,reducing CEICR appears to prompt companies to increase employee wages.Corporate cash flow is a possible channel of influence.Moreover,the positive effect is found to be more pronounced in companies that are more labor intensive,performing better in labor payment compliance,and located in regions with higher pressure for elderly care.This paper offers evidence in favor of implementing CEICR reduction policies from the perspective of improving the well-being of employees.
基金the financial support from Beijing Social Science Foundation(16YJA007)the earmarked fund for Beijing Innovation Consortium of Agriculture Research System(BAIC07-2013).
文摘China is the largest producer and consumer of vegetables,its vegetable industry is playing an important role in the domestic agricultural sector and global vegetable export market.It is important to promote the long-term sustainable development of Chinese vegetable industry for food security and quality of people’s lives.To find out the intrinsic way to promote the development of Chinese vegetable industry,this paper analyzed the influencing factors of Chinese vegetable production by utilizing the LMDI method and demonstrated the spatial-temporal characteristics of vegetable production through application of the Arc-GIS spatial autocorrelation analysis method.The results showed that the influencing factors of vegetable production were the cultivated land area,multiple cropping index,vegetable planting proportion and vegetable yield per hectare in China.The major driving factor had changed from vegetable planting proportion to vegetable yield per hectare.The influencing degrees of factors on vegetable production are different in different regions,regionalization is therefore a major feature of Chinese vegetable production.The government should take production technology,regionalization-driven effect,and marketing integration into consideration to promote the development of Chinese vegetable industry.
