As a concept to describe development restrictions,resources and environment carrying capacity（RECC）research has developed over more than 100 years since it was first proposed at the beginning of the 20th century.It ...As a concept to describe development restrictions,resources and environment carrying capacity（RECC）research has developed over more than 100 years since it was first proposed at the beginning of the 20th century.It is now regarded as a significant factor in evaluating the level of cooperation between regional population,resources,and environment;and it is currently used as an effective and operational tool to guide regional sustainable development.This article first reviews the origin of RECC and its early headway.It then reviews the historical development of RECC from single factors,such as land resources carrying capacity,water resources carrying capacity and environmental carrying capacity（environmental capacity）,to more comprehensive research,such as comprehensive evaluation,emergy analysis,and ecological footprint analysis.In general,it appears that comprehensive research will become increasingly important in RECC research.However,there are several deficiencies in the current state of comprehensive research.Firstly,comprehensive RECC research lacks a common measurement standard,though some scholars have attempted to create one.Secondly,the RECC evaluation of open systems and dynamic studies should be strengthened.Thirdly,more attention should be paid to standardization,digitalization,and systematization to promote the applicability of RECC research to national practical demands.展开更多
Mine environmental evaluation is the key to mine environmental study. On the basis of the characteristics of the mine environmental problems, they are classified into （1） three wastes problem, （2） ground distortio...Mine environmental evaluation is the key to mine environmental study. On the basis of the characteristics of the mine environmental problems, they are classified into （1） three wastes problem, （2） ground distortion, （3） contradiction among mine drainage, water supply, ecological environment, （4） desertification, and （5） soil erosion. The evaluation is the basis of mine environmental problem classification and investigation, mine environmental rehabilitation, and the information system constructed can be used for subsequent research of evaluation techniques. A synthetic assessment of the 5 kinds of mine environmental problems can be divided into single-factor or multi-factor synthetic assessments; while by the viewpoint of time, the mine environmental assessment can be classified as the historical assessment, the current status assessment and the forecasting assessment.展开更多
To determine proper flight parameters of an unmanned helicopter for tea plantation frost protection,field experiments were conducted to study the impact of flight height,speed and interval on airflow disturbance and t...To determine proper flight parameters of an unmanned helicopter for tea plantation frost protection,field experiments were conducted to study the impact of flight height,speed and interval on airflow disturbance and temperature rise around tea canopies based on the analysis and simulation of frost protection with a certain helicopter.The relationship between temperature rise after flight and the above flight parameters was established through a regression orthogonal experiment,based on which the optimal combination of flight parameters was obtained through the single-factor golden section method.The results showed that wind speed around tea canopies decreased with the increase of flight height when flight speed was constant.There was a multivariate linear relationship between temperature rise and flight parameters,and the sequence of flight parameters’influence on frost protection effect was flight interval,flight height,flight speed.The optimal combination of flight parameters were flight height of 4.0 m,flight speed of 6.0 m/s and flight interval of 20 min.After the flight with the above parameters air temperature around tea canopies increased 1.6℃ when background thermal inversion strength was 3.8℃.展开更多
To address the serious pollution of heavy metals in AMD,the difficulty and the high cost of treatment,Fe_(3)O_(4)-L was prepared by the chemical co-precipitation method.Based on the single-factor and RSM,the effects o...To address the serious pollution of heavy metals in AMD,the difficulty and the high cost of treatment,Fe_(3)O_(4)-L was prepared by the chemical co-precipitation method.Based on the single-factor and RSM,the effects of particle size,total Fe concentration,the molar ratio of Fe^(2+)to Fe^(3+)and water bath temperature on the removal of AMD by Fe_(3)O_(4)-L prepared by chemical co-precipitation method were analyzed.Static adsorption experiments were conducted on Cu^(2+),Zn^(2+)and Pb^(2+)using Fe_(3)O_(4)-L prepared under optimal conditions as adsorbents.The adsorption properties and mechanisms were analyzed by combining SEM-EDS,XRD and FTIR for characterization.The study showed that the effects of particle size,total Fe concentration and the molar ratio of Fe^(2+)to Fe^(3+)are larger.Obtained by response surface optimization analysis,the optimum conditions for the preparation of Fe_(3)O_(4)-L were a particle size of 250 mesh,a total Fe concentration of 0.5 mol/L,and a molar ratio of Fe^(2+)to Fe^(3+)of 1:2.Under these conditions,the removal rates of Cu^(2+),Zn^(2+),and Pb^(2+)were 94.52%,88.49%,and 96.69%respectively.The adsorption of Cu^(2+),Zn^(2+)and Pb^(2+)by Fe_(3)O_(4)-L prepared under optimal conditions reached equilibrium at 180 min,with removal rates of 99.99%,85.27%,and 97.48%,respectively.The adsorption reaction of Fe_(3)O_(4)-L for Cu^(2+)and Zn^(2+)is endothermic,while that for Pb^(2+)is exothermic.Fe_(3)O_(4)-L can still maintain a high adsorption capacity after five cycles of adsorption-desorption experiments.Cu^(2+),Zn^(2+)and Pb^(2+)mainly exist as CuFe_(2)O_(4),Zn(OH)2,ZnFe_(2)O_(4)and PbS after being adsorbed by Fe_(3)O_(4)-L,which is the result of the combination of physical diffusion,ion exchange and surface complexation reaction.展开更多
基金The National Key Research and Development Program of China(2016YFC0503500)National Science and Technology Major Project(Z2016C01G01)
文摘As a concept to describe development restrictions,resources and environment carrying capacity（RECC）research has developed over more than 100 years since it was first proposed at the beginning of the 20th century.It is now regarded as a significant factor in evaluating the level of cooperation between regional population,resources,and environment;and it is currently used as an effective and operational tool to guide regional sustainable development.This article first reviews the origin of RECC and its early headway.It then reviews the historical development of RECC from single factors,such as land resources carrying capacity,water resources carrying capacity and environmental carrying capacity（environmental capacity）,to more comprehensive research,such as comprehensive evaluation,emergy analysis,and ecological footprint analysis.In general,it appears that comprehensive research will become increasingly important in RECC research.However,there are several deficiencies in the current state of comprehensive research.Firstly,comprehensive RECC research lacks a common measurement standard,though some scholars have attempted to create one.Secondly,the RECC evaluation of open systems and dynamic studies should be strengthened.Thirdly,more attention should be paid to standardization,digitalization,and systematization to promote the applicability of RECC research to national practical demands.
基金China National Natural Science Foundation（Grant No.40572149,40772162）；National Key Project of Scientific and Technical Supporting Programs （2007BAK24B01,2006BAB16B04）；the “973” Project(Grant No.2006CB202205）the Key Projects of Ministry of Education of P.R.China（Grant No.2004-295）.
文摘Mine environmental evaluation is the key to mine environmental study. On the basis of the characteristics of the mine environmental problems, they are classified into （1） three wastes problem, （2） ground distortion, （3） contradiction among mine drainage, water supply, ecological environment, （4） desertification, and （5） soil erosion. The evaluation is the basis of mine environmental problem classification and investigation, mine environmental rehabilitation, and the information system constructed can be used for subsequent research of evaluation techniques. A synthetic assessment of the 5 kinds of mine environmental problems can be divided into single-factor or multi-factor synthetic assessments; while by the viewpoint of time, the mine environmental assessment can be classified as the historical assessment, the current status assessment and the forecasting assessment.
基金The authors are grateful to the financial support by National High Technology Research and Development Program of China(2012AA10A508)National Natural Science Foundation of China(31101089)Priority Academic Program Development of Jiangsu Higher Education Institutions(2014-37)。
文摘To determine proper flight parameters of an unmanned helicopter for tea plantation frost protection,field experiments were conducted to study the impact of flight height,speed and interval on airflow disturbance and temperature rise around tea canopies based on the analysis and simulation of frost protection with a certain helicopter.The relationship between temperature rise after flight and the above flight parameters was established through a regression orthogonal experiment,based on which the optimal combination of flight parameters was obtained through the single-factor golden section method.The results showed that wind speed around tea canopies decreased with the increase of flight height when flight speed was constant.There was a multivariate linear relationship between temperature rise and flight parameters,and the sequence of flight parameters’influence on frost protection effect was flight interval,flight height,flight speed.The optimal combination of flight parameters were flight height of 4.0 m,flight speed of 6.0 m/s and flight interval of 20 min.After the flight with the above parameters air temperature around tea canopies increased 1.6℃ when background thermal inversion strength was 3.8℃.
基金This work was supported by the National Natural Science Foundation of China(41672247)Liaoning Province’s“Program for Promoting Liaoning Talents”(XLYC1807159)+1 种基金the Discipline Innovation Team of Liaoning Technical University(LNTU20TD-21)the Liaoning Provincial Department of Education(LJKZ0324).
文摘To address the serious pollution of heavy metals in AMD,the difficulty and the high cost of treatment,Fe_(3)O_(4)-L was prepared by the chemical co-precipitation method.Based on the single-factor and RSM,the effects of particle size,total Fe concentration,the molar ratio of Fe^(2+)to Fe^(3+)and water bath temperature on the removal of AMD by Fe_(3)O_(4)-L prepared by chemical co-precipitation method were analyzed.Static adsorption experiments were conducted on Cu^(2+),Zn^(2+)and Pb^(2+)using Fe_(3)O_(4)-L prepared under optimal conditions as adsorbents.The adsorption properties and mechanisms were analyzed by combining SEM-EDS,XRD and FTIR for characterization.The study showed that the effects of particle size,total Fe concentration and the molar ratio of Fe^(2+)to Fe^(3+)are larger.Obtained by response surface optimization analysis,the optimum conditions for the preparation of Fe_(3)O_(4)-L were a particle size of 250 mesh,a total Fe concentration of 0.5 mol/L,and a molar ratio of Fe^(2+)to Fe^(3+)of 1:2.Under these conditions,the removal rates of Cu^(2+),Zn^(2+),and Pb^(2+)were 94.52%,88.49%,and 96.69%respectively.The adsorption of Cu^(2+),Zn^(2+)and Pb^(2+)by Fe_(3)O_(4)-L prepared under optimal conditions reached equilibrium at 180 min,with removal rates of 99.99%,85.27%,and 97.48%,respectively.The adsorption reaction of Fe_(3)O_(4)-L for Cu^(2+)and Zn^(2+)is endothermic,while that for Pb^(2+)is exothermic.Fe_(3)O_(4)-L can still maintain a high adsorption capacity after five cycles of adsorption-desorption experiments.Cu^(2+),Zn^(2+)and Pb^(2+)mainly exist as CuFe_(2)O_(4),Zn(OH)2,ZnFe_(2)O_(4)and PbS after being adsorbed by Fe_(3)O_(4)-L,which is the result of the combination of physical diffusion,ion exchange and surface complexation reaction.
