[Obective] This study amied to evaluate the direct usage value of Liangzi Lake, like plants and animal resources and water storage value. [Method] It was measured through the market value method. The physical environm...[Obective] This study amied to evaluate the direct usage value of Liangzi Lake, like plants and animal resources and water storage value. [Method] It was measured through the market value method. The physical environment was introduced and the productivity of the lake was investigated both through the literature materials and the investigations. The market value method was clarified in this paper as well as its operation process and the application fields. [Result] Based on the introduction of the current situation in Liangzi Lake, the direct usage value was estimated as 1.32 billion Yuan/year. Plant resources value was 318 million Yuan/year; animal resources value was 675 million Yuan/year; and water storage value was 325 million Yuan/year for the three parts. [Conclusion] This paper will attract more attention to the emphasis of the reasonable development of nature sources.展开更多
The Internet of Things （loT） is called the world＇ s third wave of the information industry. As the core technology of IoT, Cognitive Radio Sensor Networks （CRSN） technology can improve spectrum utilization effici...The Internet of Things （loT） is called the world＇ s third wave of the information industry. As the core technology of IoT, Cognitive Radio Sensor Networks （CRSN） technology can improve spectrum utilization efficiency and lay a sofid foundation for large-scale application of IoT. Reliable spectrum sensing is a crucial task of the CR. For energy de- tection, threshold will determine the probability of detection （Pd） and the probability of false alarm Pf at the same time. While the threshold increases, Pd and Pf will both decrease. In this paper we focus on the maximum of the difference of Pd and Pf, and try to find out how to determine the threshold with this precondition. Simulation results show that the proposed method can effectively approach the ideal optimal result.展开更多
The spacing–burden(S/B) ratio plays significant role on rock fragmentation and proper utilization of explosive energy to minimize the undesirable damage.Low S/B ratio generates fine fragments due to pressure rings co...The spacing–burden(S/B) ratio plays significant role on rock fragmentation and proper utilization of explosive energy to minimize the undesirable damage.Low S/B ratio generates fine fragments due to pressure rings coalescence of two blast holes,whereas boulder generations were observed above optimum S/B ratio.Both conditions are not acceptable because of wastage of explosive energy.Therefore,to resolve this issue,a numerical model study was conducted to optimize the S/B ratio and to envisage its effect on rock fragmentation based on utilization of explosive energy.Finite element simulation tool was used to see the extent of two blast hole influence area variation with varying S/B ratio.The better results were obtained at S/B ratio of 1:2 with optimum utilization of peak explosive energy.The performance was observed based on peak kinetic energy,peak pressure,radial and hoop stresses on centre of the two blast holes,where pressure rings coalescence.展开更多
The urgency of increasing energy efficiency in new building design and retrofits has pushed lighting simulation to play a central role in sustainable lighting design. The shape of the building and its orientation, the...The urgency of increasing energy efficiency in new building design and retrofits has pushed lighting simulation to play a central role in sustainable lighting design. The shape of the building and its orientation, the reflectances of building surfaces and glazed areas are important parameters in the daylighting design of buildings. Glazing systems can cut energy consumption and associated pollution sources, reduce peak demand, enhance daylighting performance and improve occupant comfort. This paper presents the results of a numerical and experimental comparison between the performances of an office building with and without external sunscreens. The aim was to analyse the illuminance distribution and some investigations have also been made with regards to the effect on daylight in rooms when sunscreens are used. The experimental results were obtained using an office building scale model and sky simulator. The numerical results were obtained through radiance, the ray-tracing program, to accurately predict the light levels and produce photo realistic images of the architectural space in all sky conditions： Illuminance values were obtained respectively through reference point measurements. The daylighting performances of the office building model with and without the sunscreens have been compared and analysed.展开更多
Miyun County,located in the northeast of Chinese capital Beijing,was underwent remarkable variations in land use in recent years.This paper aimed to detect changes in land use of Miyun from 1997 to 2005,and to qualify...Miyun County,located in the northeast of Chinese capital Beijing,was underwent remarkable variations in land use in recent years.This paper aimed to detect changes in land use of Miyun from 1997 to 2005,and to qualify the response of ecosystem to LUCC based on ecosystem services valuation.With two-periods TM images,we got land use change data,and then ecosystem services values were calculated using ecosystem services valuation coefficients proposed by Chinese scholar Xie Gaodi.Results showed that water area,farm land and unused land decreased while residential land,forest land,grassland and orchard land increased during the study period.The loss of ESV was RMB 206 million and the main reason was the decrease of water area and farm land area.As for spatial variation,there were most dramatically land use change and ESV decline in reservoir ecological protection region.The coefficient sensitivity analysis indicates that valuation coefficients used in the study are suitable and results are reasonable.The driving forces of ESV loss were rapid population growth and economic development.More work should be done to make eco-environment stay healthy.展开更多
Active exploitation of solar energy is achieved in systems that absorb this energy through flat collectors. Hot water can be used for space heating, when its temperature is high, but it is used largely for DHW （domes...Active exploitation of solar energy is achieved in systems that absorb this energy through flat collectors. Hot water can be used for space heating, when its temperature is high, but it is used largely for DHW （domestic hot water） needs. Now days, this technology has resulted as the most viable for exploitation of solar energy, and various countries such as Israel, Turkey, and Greece provide hot water for residential and service sectors using systems of solar panels. In this proceeding we are writing about the dimension of the solar panels surface based to the net present value in Hotels of Albania.展开更多
Oases are important habitats for human survival and development in northwest arid China;however, they are fragile. To realize ecological construction and sustainable development in northwest China, an analysis of the ...Oases are important habitats for human survival and development in northwest arid China;however, they are fragile. To realize ecological construction and sustainable development in northwest China, an analysis of the economic and ecological benefits of the oasis system with a focus on sustainability and land use optimization of oasis agro-economic systems are needed. This paper selects Fukang City as a study area. It is located on the northern slope of Mt Tianshan, Xinjiang Uygur Autonomous Region. The authors discuss the ecological and economic benefits of the oasis system, annual variation and establish an optimized allocation scheme of oasis land use structure in Fukang City based on emergy analysis and linear programming modeling. From 1996 to 2006 the oasis system was in a weak sustainable development state. Ecological and economic benefits analysis of the oasis system based on emergy analysis shows that the development of an oasis system in Fukang City is restricted by land, climate and water resources, being a typical example of the high-input and low-output type. The comparative advantage analysis of oasis cropping based on economics and ecological economics shows that the farming structure will vary across different goals. If the maximum ecological efficiency is pursued, farming structure is determined by emergy density;and if the maximum ecological and economic benefits with limited water resources are pursued, farming structure is determined by the emergy value per unit area of irrigation.展开更多
Electrocatalysis is deemed as a promising approach for sustainable energy conversion and chemical production.Although a variety of cathode reactions(e.g.,hydrogen evolution and CO_(2)/N_(2)reduction)produce valuable f...Electrocatalysis is deemed as a promising approach for sustainable energy conversion and chemical production.Although a variety of cathode reactions(e.g.,hydrogen evolution and CO_(2)/N_(2)reduction)produce valuable fuels and chemicals,the extensively studied oxygen evolution reaction(OER)at anode only generates O_(2),which is not a high-value product.Substituting the OER with thermodynamically more favorable biomass derivative oxidation reactions(BDORs)not only enables energy-saving electrocatalysis,but also provides value-added anode products.Recent achievements have demonstrated that non-noble electrocatalysts are promising for BDORs.Herein,we provide a comprehensive review on recent achievements in the field of electrochemical BDORs catalyzed by non-noble catalysts.We start by summarizing the electrocatalytic oxidation of different types of biomass-derived substrates,aiming to show the advantages of the electrocatalytic pathway and to introduce the state-of-the-art non-noble catalysts.The reaction mechanisms of non-noble-material-catalyzed BDORs are then summarized and classified into three types according to the acceptor of hydrogen species during the dehydrogenation of biomass derivatives.Subsequently,discussions are devoted to the strategies for promoting the performances of non-noble electrocatalysts.Finally,we propose our opinions regarding future trends and major challenges in this field.展开更多
文摘[Obective] This study amied to evaluate the direct usage value of Liangzi Lake, like plants and animal resources and water storage value. [Method] It was measured through the market value method. The physical environment was introduced and the productivity of the lake was investigated both through the literature materials and the investigations. The market value method was clarified in this paper as well as its operation process and the application fields. [Result] Based on the introduction of the current situation in Liangzi Lake, the direct usage value was estimated as 1.32 billion Yuan/year. Plant resources value was 318 million Yuan/year; animal resources value was 675 million Yuan/year; and water storage value was 325 million Yuan/year for the three parts. [Conclusion] This paper will attract more attention to the emphasis of the reasonable development of nature sources.
基金supported in part by the National Natural Science Foundation of China(Grant Nos.60971082,60872049,60972073and60871042)the National Key Basic Research Program of China(Grant No.2009CB320400)+1 种基金the National Great Science Specific Project(Grant Nos.2009ZX03003-001,2009ZX03003-011and2010ZX03001003)Chinese Universities Scientific Fund,China
文摘The Internet of Things （loT） is called the world＇ s third wave of the information industry. As the core technology of IoT, Cognitive Radio Sensor Networks （CRSN） technology can improve spectrum utilization efficiency and lay a sofid foundation for large-scale application of IoT. Reliable spectrum sensing is a crucial task of the CR. For energy de- tection, threshold will determine the probability of detection （Pd） and the probability of false alarm Pf at the same time. While the threshold increases, Pd and Pf will both decrease. In this paper we focus on the maximum of the difference of Pd and Pf, and try to find out how to determine the threshold with this precondition. Simulation results show that the proposed method can effectively approach the ideal optimal result.
文摘The spacing–burden(S/B) ratio plays significant role on rock fragmentation and proper utilization of explosive energy to minimize the undesirable damage.Low S/B ratio generates fine fragments due to pressure rings coalescence of two blast holes,whereas boulder generations were observed above optimum S/B ratio.Both conditions are not acceptable because of wastage of explosive energy.Therefore,to resolve this issue,a numerical model study was conducted to optimize the S/B ratio and to envisage its effect on rock fragmentation based on utilization of explosive energy.Finite element simulation tool was used to see the extent of two blast hole influence area variation with varying S/B ratio.The better results were obtained at S/B ratio of 1:2 with optimum utilization of peak explosive energy.The performance was observed based on peak kinetic energy,peak pressure,radial and hoop stresses on centre of the two blast holes,where pressure rings coalescence.
文摘The urgency of increasing energy efficiency in new building design and retrofits has pushed lighting simulation to play a central role in sustainable lighting design. The shape of the building and its orientation, the reflectances of building surfaces and glazed areas are important parameters in the daylighting design of buildings. Glazing systems can cut energy consumption and associated pollution sources, reduce peak demand, enhance daylighting performance and improve occupant comfort. This paper presents the results of a numerical and experimental comparison between the performances of an office building with and without external sunscreens. The aim was to analyse the illuminance distribution and some investigations have also been made with regards to the effect on daylight in rooms when sunscreens are used. The experimental results were obtained using an office building scale model and sky simulator. The numerical results were obtained through radiance, the ray-tracing program, to accurately predict the light levels and produce photo realistic images of the architectural space in all sky conditions： Illuminance values were obtained respectively through reference point measurements. The daylighting performances of the office building model with and without the sunscreens have been compared and analysed.
基金supported by the Hi-tech Research and Development Program of China(Grant No.2006AA120108)
文摘Miyun County,located in the northeast of Chinese capital Beijing,was underwent remarkable variations in land use in recent years.This paper aimed to detect changes in land use of Miyun from 1997 to 2005,and to qualify the response of ecosystem to LUCC based on ecosystem services valuation.With two-periods TM images,we got land use change data,and then ecosystem services values were calculated using ecosystem services valuation coefficients proposed by Chinese scholar Xie Gaodi.Results showed that water area,farm land and unused land decreased while residential land,forest land,grassland and orchard land increased during the study period.The loss of ESV was RMB 206 million and the main reason was the decrease of water area and farm land area.As for spatial variation,there were most dramatically land use change and ESV decline in reservoir ecological protection region.The coefficient sensitivity analysis indicates that valuation coefficients used in the study are suitable and results are reasonable.The driving forces of ESV loss were rapid population growth and economic development.More work should be done to make eco-environment stay healthy.
文摘Active exploitation of solar energy is achieved in systems that absorb this energy through flat collectors. Hot water can be used for space heating, when its temperature is high, but it is used largely for DHW （domestic hot water） needs. Now days, this technology has resulted as the most viable for exploitation of solar energy, and various countries such as Israel, Turkey, and Greece provide hot water for residential and service sectors using systems of solar panels. In this proceeding we are writing about the dimension of the solar panels surface based to the net present value in Hotels of Albania.
基金National Basic Research Program of China(2009CB421307)National Natural Science Foundation of China(40971282)
文摘Oases are important habitats for human survival and development in northwest arid China;however, they are fragile. To realize ecological construction and sustainable development in northwest China, an analysis of the economic and ecological benefits of the oasis system with a focus on sustainability and land use optimization of oasis agro-economic systems are needed. This paper selects Fukang City as a study area. It is located on the northern slope of Mt Tianshan, Xinjiang Uygur Autonomous Region. The authors discuss the ecological and economic benefits of the oasis system, annual variation and establish an optimized allocation scheme of oasis land use structure in Fukang City based on emergy analysis and linear programming modeling. From 1996 to 2006 the oasis system was in a weak sustainable development state. Ecological and economic benefits analysis of the oasis system based on emergy analysis shows that the development of an oasis system in Fukang City is restricted by land, climate and water resources, being a typical example of the high-input and low-output type. The comparative advantage analysis of oasis cropping based on economics and ecological economics shows that the farming structure will vary across different goals. If the maximum ecological efficiency is pursued, farming structure is determined by emergy density;and if the maximum ecological and economic benefits with limited water resources are pursued, farming structure is determined by the emergy value per unit area of irrigation.
基金supported by the National Natural Science Foundation of China (21978147 and 21935001)Haihe Laboratory of Sustainable Chemical Transformationssupported by the Shuimu Tsinghua Scholar Program (2021SM072)
文摘Electrocatalysis is deemed as a promising approach for sustainable energy conversion and chemical production.Although a variety of cathode reactions(e.g.,hydrogen evolution and CO_(2)/N_(2)reduction)produce valuable fuels and chemicals,the extensively studied oxygen evolution reaction(OER)at anode only generates O_(2),which is not a high-value product.Substituting the OER with thermodynamically more favorable biomass derivative oxidation reactions(BDORs)not only enables energy-saving electrocatalysis,but also provides value-added anode products.Recent achievements have demonstrated that non-noble electrocatalysts are promising for BDORs.Herein,we provide a comprehensive review on recent achievements in the field of electrochemical BDORs catalyzed by non-noble catalysts.We start by summarizing the electrocatalytic oxidation of different types of biomass-derived substrates,aiming to show the advantages of the electrocatalytic pathway and to introduce the state-of-the-art non-noble catalysts.The reaction mechanisms of non-noble-material-catalyzed BDORs are then summarized and classified into three types according to the acceptor of hydrogen species during the dehydrogenation of biomass derivatives.Subsequently,discussions are devoted to the strategies for promoting the performances of non-noble electrocatalysts.Finally,we propose our opinions regarding future trends and major challenges in this field.
