Diesel particulate matter （DPM） is considered to be carcinogenic after prolonged exposure. With more diesel- powered equipment used in underground mines, miners＇ exposure to DPM has become an increasing concern. Th...Diesel particulate matter （DPM） is considered to be carcinogenic after prolonged exposure. With more diesel- powered equipment used in underground mines, miners＇ exposure to DPM has become an increasing concern. This paper used computational fluid dynamics method to study the DPM dispersion in a dead-end entry with loading operation. The effects of different push-pull ventilation systems on DPM distribution were evaluated to improve the working conditions for underground miners. The four push-pull systems considered include： long push and short pull tubing; short push and long pull tubing, long push and curved pull tubing, and short push and curved pull tubing. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup local ventilation, select DPM control strategies and for DPM annual training for underground miners.展开更多
The spatiotemporal features of carbon and nitrogen fluxes over China between 1979 and 2015were simulated by the Atmosphere–Vegetation Interaction Model(AVIM).The carbon fluxes of gross primary production and net prim...The spatiotemporal features of carbon and nitrogen fluxes over China between 1979 and 2015were simulated by the Atmosphere–Vegetation Interaction Model(AVIM).The carbon fluxes of gross primary production and net primary production captured the distribution pattern in China better than MODIS and TRENDY data.The results for nitrogen deposition and biological nitrogen fixation show the good performance of the AVIM simulation compared with the CMIP6 and CABLE data,with a deposition rate>4 g N m-2yr-1in south China.The variation in the gross primary production and net primary production can be up to 300 and 200 g C m-2yr-1in south and southeast China,respectively,and there is a discrepancy between the AVIM and the data from MODIS and TRENDY.This shows the difficulty in simulating the carbon flux in a monsoon climate region and the importance of coupling the nitrogen–carbon fluxes.The standard deviation of nitrogen deposition and biological nitrogen fixation is simulated well by the AVIM and there is a large range in nitrogen deposition of 0.8–1.2 g N m-2yr-1in south China.The climatological mean of the fluxes performs better than the variation in the standard deviation and anomaly and this variation in the carbon–nitrogen flux is the key to decreasing bias in future modeling studies.展开更多
The dynamics of regional convergence include spatial and temporal dimensions. Spatial Markov chain can be used to explore how regions evolve by considering both individual regions and their geographic neighbors. Based...The dynamics of regional convergence include spatial and temporal dimensions. Spatial Markov chain can be used to explore how regions evolve by considering both individual regions and their geographic neighbors. Based on per capita GDP data set of 77 counties from 1978 to 2000, this paper attempts to investigate the spatial-temporal dynamics of regional convergence in Jiangsu. First, traditional Markov matrix for five per capita GDP classes is constructed for later comparison. Moreover, each region’s spatial lag is derived by averaging all its neighbors’ per capita GDP data. Conditioning on per capita GDP class of its spatial lag at the beginning of each year, spatial Markov transition probabilities of each region are calculated accordingly. Quantitatively, for a poor region, the probability of moving upward is 3.3% if it is surrounded by its poor neighbors, and even increases to 18.4% if it is surrounded by its rich neighbors, but it goes down to 6.2% on average if ignoring regional context. For a rich region, the probability of moving down ward is 1.2% if it is surrounded by its rich neighbors, but increases to 3.0% if it is surrounded by its poor neighbors, and averages 1.5% irrespective of regional context. Spatial analysis of regional GDP class transitions indicates those 10 upward moves of both regions and their neighbors are unexceptionally located in the southern Jiangsu, while downward moves of regions or their neighbors are almost in the northern Jiangsu. These empirical results provide a spatial explanation to the "convergence clubs" detected by traditional Markov chain.展开更多
With a scientific consensus reached regarding the anthropogenic effect on global mean temperature, developing reliable regional climate projections has emerged as a new challenge for climate science. A national projec...With a scientific consensus reached regarding the anthropogenic effect on global mean temperature, developing reliable regional climate projections has emerged as a new challenge for climate science. A national project was launched in China in 2012 to study ocean's role in regional climate change. This paper starts with a review of recent advances in the study of regional climate re-sponse to global warming, followed by a description of the Chinese project including the rationale, objectives, and plan for field ob-servations. The 15 research articles that follow in the special issue are highlighted, representing some of the initial results from the project.展开更多
Shandong Peninsula,as a more developed region in Shandong Province even the east coast of China,is facing challenges from resources and environment pressures.This paper tried to track and assess the coordination statu...Shandong Peninsula,as a more developed region in Shandong Province even the east coast of China,is facing challenges from resources and environment pressures.This paper tried to track and assess the coordination status and the dynamic between resource-environment and economy-society systems in Shandong Peninsula during 2001-2008 in order to provide decision support for regional sustainability.An appraisal index system was built including five aspects of harmony degree(A),sustainability degree(B),opening degree(C),stability degree(D) and controllability degree(E).The results showed that:1) The coordination level of resource-environment and economy-society in Shandong Peninsula has continuously grown,and it has undergone three stages:no coordinated degree(2001-2002),weak coordinated degree(2003-2006) and basically coordinated degree(2007-2008).2) Five indexes of criterion hierarchy also increased overall,but each index showed different trends.Harmony degree,sustainability degree and opening degree rose all the time,while stability degree and controllability degree alternately rose and fell.The improvement of controllability degree was the slowest.3) The aggravating trend of environmental pollution was slowing down.The economic growth was driven by industrial growth and urbanization typically and investment was still the main force to pull the regional economic growth.At the same time,technology and education were becoming more and more important for economic growth.The level of foreign capital utility declined and the geographical advantage of Shandong Peninsula was exerted.Meanwhile some characteristics of knowledge economy were presenting.Water resources become the main constraint factor of fast development in Shandong Peninsula.It is necessary to further strengthen the coordination ability of government on regional sustainable development.展开更多
In this work we show that homogeneous Neumann boundary conditions inhibit the Coleman-Weinberg mechanism for spontaneous symmetry breaking in the scalar electrodynamics if the length of the finite region is small enou...In this work we show that homogeneous Neumann boundary conditions inhibit the Coleman-Weinberg mechanism for spontaneous symmetry breaking in the scalar electrodynamics if the length of the finite region is small enough （a = e2Mφ-1, where M, is the mass of the scalar field generated by the Coleman-Weinberg mechanism）.展开更多
The marine area of Japan, including territorial waters and the exclusive economic zone, is the sixth largest in the world at about 4,470,000 km2. Therefore, it is becoming necessary to establish appropriate means of t...The marine area of Japan, including territorial waters and the exclusive economic zone, is the sixth largest in the world at about 4,470,000 km2. Therefore, it is becoming necessary to establish appropriate means of transportation other than ships in order to utilize the area efficiently. In this respect, ultra-light seaplanes are attracting attention from the viewpoint of protecting the natural environment. Accordingly, JRPS （Japan Reinforced Plastics Society） is currently developing FRP （fiber-reinforced plastic） floats for such planes. In this study, we conducted simulations of seaplane behavior during alighting by using the smoothed particle hydrodynamics method, which is one of the functions in the PAM-CRASH solver, and we present the observed trend in the vertical acceleration of the floats as a first step toward deriving the impact force from analytical data.展开更多
文摘Diesel particulate matter （DPM） is considered to be carcinogenic after prolonged exposure. With more diesel- powered equipment used in underground mines, miners＇ exposure to DPM has become an increasing concern. This paper used computational fluid dynamics method to study the DPM dispersion in a dead-end entry with loading operation. The effects of different push-pull ventilation systems on DPM distribution were evaluated to improve the working conditions for underground miners. The four push-pull systems considered include： long push and short pull tubing; short push and long pull tubing, long push and curved pull tubing, and short push and curved pull tubing. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup local ventilation, select DPM control strategies and for DPM annual training for underground miners.
基金jointly supported by the project of the National Key R&D Program of China grant No. 2018YFA0606004the National Natural Science Foundation of China grant Nos.41630532 and 41975112。
文摘The spatiotemporal features of carbon and nitrogen fluxes over China between 1979 and 2015were simulated by the Atmosphere–Vegetation Interaction Model(AVIM).The carbon fluxes of gross primary production and net primary production captured the distribution pattern in China better than MODIS and TRENDY data.The results for nitrogen deposition and biological nitrogen fixation show the good performance of the AVIM simulation compared with the CMIP6 and CABLE data,with a deposition rate>4 g N m-2yr-1in south China.The variation in the gross primary production and net primary production can be up to 300 and 200 g C m-2yr-1in south and southeast China,respectively,and there is a discrepancy between the AVIM and the data from MODIS and TRENDY.This shows the difficulty in simulating the carbon flux in a monsoon climate region and the importance of coupling the nitrogen–carbon fluxes.The standard deviation of nitrogen deposition and biological nitrogen fixation is simulated well by the AVIM and there is a large range in nitrogen deposition of 0.8–1.2 g N m-2yr-1in south China.The climatological mean of the fluxes performs better than the variation in the standard deviation and anomaly and this variation in the carbon–nitrogen flux is the key to decreasing bias in future modeling studies.
基金Under the auspices ofthe National Natural Science Foundation of China (No .40301038)
文摘The dynamics of regional convergence include spatial and temporal dimensions. Spatial Markov chain can be used to explore how regions evolve by considering both individual regions and their geographic neighbors. Based on per capita GDP data set of 77 counties from 1978 to 2000, this paper attempts to investigate the spatial-temporal dynamics of regional convergence in Jiangsu. First, traditional Markov matrix for five per capita GDP classes is constructed for later comparison. Moreover, each region’s spatial lag is derived by averaging all its neighbors’ per capita GDP data. Conditioning on per capita GDP class of its spatial lag at the beginning of each year, spatial Markov transition probabilities of each region are calculated accordingly. Quantitatively, for a poor region, the probability of moving upward is 3.3% if it is surrounded by its poor neighbors, and even increases to 18.4% if it is surrounded by its rich neighbors, but it goes down to 6.2% on average if ignoring regional context. For a rich region, the probability of moving down ward is 1.2% if it is surrounded by its rich neighbors, but increases to 3.0% if it is surrounded by its poor neighbors, and averages 1.5% irrespective of regional context. Spatial analysis of regional GDP class transitions indicates those 10 upward moves of both regions and their neighbors are unexceptionally located in the southern Jiangsu, while downward moves of regions or their neighbors are almost in the northern Jiangsu. These empirical results provide a spatial explanation to the "convergence clubs" detected by traditional Markov chain.
基金supported by the National Basic Research Program of China(2012CB955600)
文摘With a scientific consensus reached regarding the anthropogenic effect on global mean temperature, developing reliable regional climate projections has emerged as a new challenge for climate science. A national project was launched in China in 2012 to study ocean's role in regional climate change. This paper starts with a review of recent advances in the study of regional climate re-sponse to global warming, followed by a description of the Chinese project including the rationale, objectives, and plan for field ob-servations. The 15 research articles that follow in the special issue are highlighted, representing some of the initial results from the project.
基金National Social Science Foundation of China (Grant No.03CJL008)Natural Science Foundation of Shandong Province(Grant No.Y2007E04)
文摘Shandong Peninsula,as a more developed region in Shandong Province even the east coast of China,is facing challenges from resources and environment pressures.This paper tried to track and assess the coordination status and the dynamic between resource-environment and economy-society systems in Shandong Peninsula during 2001-2008 in order to provide decision support for regional sustainability.An appraisal index system was built including five aspects of harmony degree(A),sustainability degree(B),opening degree(C),stability degree(D) and controllability degree(E).The results showed that:1) The coordination level of resource-environment and economy-society in Shandong Peninsula has continuously grown,and it has undergone three stages:no coordinated degree(2001-2002),weak coordinated degree(2003-2006) and basically coordinated degree(2007-2008).2) Five indexes of criterion hierarchy also increased overall,but each index showed different trends.Harmony degree,sustainability degree and opening degree rose all the time,while stability degree and controllability degree alternately rose and fell.The improvement of controllability degree was the slowest.3) The aggravating trend of environmental pollution was slowing down.The economic growth was driven by industrial growth and urbanization typically and investment was still the main force to pull the regional economic growth.At the same time,technology and education were becoming more and more important for economic growth.The level of foreign capital utility declined and the geographical advantage of Shandong Peninsula was exerted.Meanwhile some characteristics of knowledge economy were presenting.Water resources become the main constraint factor of fast development in Shandong Peninsula.It is necessary to further strengthen the coordination ability of government on regional sustainable development.
文摘In this work we show that homogeneous Neumann boundary conditions inhibit the Coleman-Weinberg mechanism for spontaneous symmetry breaking in the scalar electrodynamics if the length of the finite region is small enough （a = e2Mφ-1, where M, is the mass of the scalar field generated by the Coleman-Weinberg mechanism）.
文摘The marine area of Japan, including territorial waters and the exclusive economic zone, is the sixth largest in the world at about 4,470,000 km2. Therefore, it is becoming necessary to establish appropriate means of transportation other than ships in order to utilize the area efficiently. In this respect, ultra-light seaplanes are attracting attention from the viewpoint of protecting the natural environment. Accordingly, JRPS （Japan Reinforced Plastics Society） is currently developing FRP （fiber-reinforced plastic） floats for such planes. In this study, we conducted simulations of seaplane behavior during alighting by using the smoothed particle hydrodynamics method, which is one of the functions in the PAM-CRASH solver, and we present the observed trend in the vertical acceleration of the floats as a first step toward deriving the impact force from analytical data.
