Dry sliding friction and wear test of Nb containing low carbon microalloyed steel was carried out at room temperature,and the effect of Nb on the wear behavior of the steel,as welll as the mechanism was studied.Scanni...Dry sliding friction and wear test of Nb containing low carbon microalloyed steel was carried out at room temperature,and the effect of Nb on the wear behavior of the steel,as welll as the mechanism was studied.Scanning electron microscopy(SEM) and energy dispersive spectrometry(EDS) were employed to analyze the morphology and composition of the worn surface,and the structure evolution of the plastic deformation layer.The carbide content and type in the steel were analyzed by the electrolytic extraction device and X-ray diffraction(XRD).The experimental results demonstrate that the addition of 0.2% Nb can refine the grain and generate Nb C to improve the wear resistance of the steel.By enhancing the load and speed of wear experiment,the wear mechanism of the test steel with 0.2% Nb changes from slight oxidation wear to severe adhesion wear and oxidation wear.Compared with the load,the increase in the rotation speed exerts a greater influence on the wear of the test steel.展开更多
The construction of relevant standards for building carbon emission assessment in China has just started,and the quantitative analysis method and evaluation system are still imperfect,which hinders the development of ...The construction of relevant standards for building carbon emission assessment in China has just started,and the quantitative analysis method and evaluation system are still imperfect,which hinders the development of low-carbon building design.Therefore,the use of intelligent energy management system is very necessary.The purpose of this paper is to explore the design optimization of low-carbon buildings based on intelligent energy management systems.Based on the proposed quantitative method of building carbon emission,this paper establishes the quota theoretical system of building carbon emission analysis,and develops the quota based carbon emission calculation software.Smart energy management system is a low-carbon energy-saving system based on the reference of large-scale building energy-saving system and combined with energy consumption.It provides a fast and effective calculation tool for the quantitative evaluation of carbon emission of construction projects,so as to realize the carbon emission control and optimization in the early stage of architectural design and construction.On this basis,the evaluation,analysis and calculation method of building structure based on carbon reduction target is proposed,combined with the carbon emission quota management standard proposed in this paper.Taking small high-rise residential buildings as an example,this paper compares and analyzes different building structural systems from the perspectives of structural performance,economy and carbon emission level.It provides a reference for the design and evaluation of low-carbon building structures.The smart energy management system collects user energy use parameters.It uses time period and time sequence to obtain a large amount of data for analysis and integration,which provides users with intuitive energy consumption data.Compared with the traditional architectural design method,the industrialized construction method can save 589.22 megajoules(MJ)per square meter.Based on 29270 megajoules(MJ)per ton of standard coal,the construction area of the case is about 8000 m2,and the energy saving of residential buildings is 161.04 tons of standard coal.This research is of great significance in reducing the carbon emission intensity of buildings.展开更多
Low carbon landscape development is an emerging approach of landscape design,which aims to promote sustainable development,and reduce energy consumption and environmental impact by reducing carbon emissions.As an impo...Low carbon landscape development is an emerging approach of landscape design,which aims to promote sustainable development,and reduce energy consumption and environmental impact by reducing carbon emissions.As an important component of low carbon landscape construction,the construction of urban pocket park system based on mini-parks plays a crucial role in improving the urban greening level,increasing the urban green space,alleviating the urban pressure,improving the living and healthy environment of urban residents,and promoting the urban ecological balance.Taking Chaowai district of Beijing as an example,this paper calculates the ecological value of trees including energy contribution,carbon sequestration,ability to improve rainfall runoff and aesthetic value by collecting the information of trees and the plot on which the trees are located through the i-Tree platform,which provides important reference value for the urban pocket park system planning to create low carbon comprehensive benefits.展开更多
Considering the growing prominence of global environmental issues,a low-carbon economy has emerged as a crucial direction for economic development across various countries.As the world’s second-largest economy,China ...Considering the growing prominence of global environmental issues,a low-carbon economy has emerged as a crucial direction for economic development across various countries.As the world’s second-largest economy,China has also witnessed the influence of a low-carbon economy on its international trade development.This article aims to commence with an exploration of the development background,meaning,and significance of a low-carbon economy.Subsequently,it delves into an in-depth analysis of the impact that a low-carbon economy has on China’s international trade.The article concludes by proposing pertinent countermeasures and suggestions.展开更多
With the continuous implementation of national measures related to carbon neutrality strategy,the concept of a low-carbon economy has been deeply rooted in people’s hearts.Low-carbon tourism has gradually become an i...With the continuous implementation of national measures related to carbon neutrality strategy,the concept of a low-carbon economy has been deeply rooted in people’s hearts.Low-carbon tourism has gradually become an inevitable trend,and the tourism industry is also undergoing orderly transformation and upgrading.To promote the sustainable development of the tourism industry,the tourism and hotel industry should also shift towards a low-carbon and green model.Hotel activities can easily bring related environmental issues,such as energy consumption,garbage generation,ecological pollution,etc.Therefore,building a green hotel will bring huge social and economic benefits to the low-carbon tourism industry.This article will address the above issues and take a low-carbon economy as the starting point,proposing sustainable development strategies and suggestions for green hotels from both the internal and external environment of the hotel,creating a low-carbon management atmosphere,and promoting the low-carbon operation of the green hotel industry.展开更多
The impact energy prediction model of low carbon steel was investigated based on industrial data. A three-layer neural network, extreme learning machine, and deep neural network were compared with different activation...The impact energy prediction model of low carbon steel was investigated based on industrial data. A three-layer neural network, extreme learning machine, and deep neural network were compared with different activation functions, structure parameters, and training functions. Bayesian optimization was used to determine the optimal hyper-parameters of the deep neural network. The model with the best performance was applied to investigate the importance of process parameter variables on the impact energy of low carbon steel. The results show that the deep neural network obtains better prediction results than those of a shallow neural network because of the multiple hidden layers improving the learning ability of the model. Among the models, the Bayesian optimization deep neural network achieves the highest correlation coefficient of 0.9536, the lowest mean absolute relative error of 0.0843, and the lowest root mean square error of 17.34 J for predicting the impact energy of low carbon steel. Among the variables, the main factors affecting the impact energy of low carbon steel with a final thickness of7.5 mm are the thickness of the original slab, the thickness of intermediate slab, and the rough rolling exit temperature from the specific hot rolling production line.展开更多
A series of self-reducing bifunctional Ni-W/SBA-15 catalysts were synthesized using biomass-based carbon source as the reducing agent without conventional further reduction step. The self-reducing catalysts were perfo...A series of self-reducing bifunctional Ni-W/SBA-15 catalysts were synthesized using biomass-based carbon source as the reducing agent without conventional further reduction step. The self-reducing catalysts were performed on the hydrogenolysis of cellulose to low carbon polyols. The effects of calcination temperature and metallic loading contents for cellulose hydrogenolysis reaction were investigated detailedly.The optimal calcination temperature was found to be 673 K by TG analysis. The active metal nanoparticles with a better dispersion were observed using SEM and element mapping technology. The yield of low carbon polyols using the catalyst with the receipt of 10%Ni-15%W/SBA-15-673 K can reach as high as68.14%, of which the ethylene glycol(EG) accounts for 61.04%.展开更多
On the basis of the concept and characteristics of circular economy, this paper analyzes the restraining factors of China's circular agricultural development as follows: issues concerning agriculture, countryside ...On the basis of the concept and characteristics of circular economy, this paper analyzes the restraining factors of China's circular agricultural development as follows: issues concerning agriculture, countryside and farmers are outstanding; the problems of agricultural resources and agricultural ecological environment are serious; the quality of agricultural products cannot meet the demand of domestic and international market for food. Based on the internal requirements of low carbon economic development, this paper advances four innovative models concerning China's circular agricultural development as follows: the model of combining planting and breeding of agriculture, the developmental model of leisure and sightseeing, ecological integration model, and the developmental model of reusing agricultural byproducts. Every region should choose or create different circular agricultural model in different domains, in order to better use agricultural resources, reduce the consumption of agricultural energy inputs, reduce the emission of agricultural greenhouse gas, develop low carbon agriculture, and make great contribution for meeting the international challenges and promoting China's agricultural development.展开更多
This work intends to provide a comprehensive review on the development of Al_(2)O_(3)-C refractories with low/ultra-low carbon content.It covers three parts:carbon materials,microstructure optimization of the refracto...This work intends to provide a comprehensive review on the development of Al_(2)O_(3)-C refractories with low/ultra-low carbon content.It covers three parts:carbon materials,microstructure optimization of the refractory matrix by ceramic phases,and application of metal Al as raw material.Carbon black,expanded graphite,and ultrafine microcrystalline graphite,as price-competitive carbon materials,can be chosen to prepare the low-carbon Al_(2)O_(3)-C refractories after some special treatment.Ni/Co/Fe-catalyzed phenolic resin contributes to improving the properties of the low-carbon Al_(2)O_(3)-C refractories.The performance deterioration of the low-carbon Al_(2)O_(3)-C refractories can also be improved by in-situ formed or pre-synthesized ceramic phases.Metal Al,characterized by plasticity forming,acceleration of sintering,oxidation resistance,and high reactivity,can be used as raw materials to completely replace graphite,and the prepared resin bonded Al-Al_(2)O_(3)based refractories are one novel development direction of the ultra-low carbon Al_(2)O_(3)-C refractories.展开更多
The low carbon Nb-Ti microalloyed tested steel was prepared by the process of vacuum induction furnace smelting,forging and hot rolling.The new steel aims to meet the demand of high strength,high toughness and high pl...The low carbon Nb-Ti microalloyed tested steel was prepared by the process of vacuum induction furnace smelting,forging and hot rolling.The new steel aims to meet the demand of high strength,high toughness and high plasticity for building facilities.The effects of quenching process on microstructure and mechanical properties of tested steel were investigated.The results showed that prior austenite grain size,phase type and precipitation behavior of(Nb,Ti)(C,N)play important roles in mechanical properties of the steel.Through modified appropriately,the model of austenite grain growth during heating and holding is d^(5.7778)=5.6478^(5.7778)+7.04×10^(22)t^(1.6136)exp(-427.15×10~3/(RT)).The grain growth activation energy is Q_g=427.15 kJ.During quenching,the microscopic structures are mainly martensite and lath bainite which contains lots of lath substructure and dislocations.The content of phases,fine and coarsening(Nb,Ti)(C,N)precipitated changes during different quenching temperatures and holding time.Finally compared with the hardness value,the best quenching process can be obtained that heating temperature and holding time are900℃and 50 mins,respectively.展开更多
This study develops a comprehensive analysis framework and socio-economic energy system model that interlinks demographic change and energy system in order to analyze the urbanization process and its relation with Chi...This study develops a comprehensive analysis framework and socio-economic energy system model that interlinks demographic change and energy system in order to analyze the urbanization process and its relation with China's long-term CO2 emissions trend as China'economy enters the“new normal”stage.The results show that,around 300 million people are expected to migrate from rural areas to urban areas by 2050 following a trend,in which people are moving gradually from small and medium city groups to large and super city groups.The migration trend together with the improvement in living standard will promote China's infrastructure construction,industry production,and energy service demand growth.Under the Business as Usual(BAU)scenario,total primary energy consumption in China will reach 8.4 Gtce by 2050,energyrelated CO2 emissions will increase to 17.6 Gt,which is 83%higher than the 2013 level.While in the Low Carbon Transition(LCT)scenario with technology innovation,the total primary energy demand for China in 2050 could be controlled at^6 Gtce;CO2 emissions would peak during 2020—2025,and be reduced by 78%by 2050 compared to the BAU scenario.In the transition process,non-fossil fuel power generation and energy efficiency technologies have the largest mitigation potentials.Industry and power sectors would peak first before 2020,followed by the building and transport sectors which are projected to peak around 2030.The total additional capital investment required for LCT would account for 1.5%of GDP.Therefore,it is technologically and economically feasible for China to implement new urbanization strategy.展开更多
The formation mechanism of the spheroidal carbide in the ultra-low carbon ductile cast iron fabricated by the metal mold casting technique was systematically investigated. The results demonstrated that the spheroidal ...The formation mechanism of the spheroidal carbide in the ultra-low carbon ductile cast iron fabricated by the metal mold casting technique was systematically investigated. The results demonstrated that the spheroidal carbide belonged to eutectic carbide and crystallized in the isolated eutectic liquid phase area. The formation process of the spheroidal carbide was related to the contact and the intersection between the primary dendrite and the secondary dendrite of austenite. The oxides of magnesium, rare earths and other elements can act as heterogeneous nucleation sites for the spheroidal carbide. It was also found that the amount of the spheroidal carbide would increase with an increase in carbon content. The cooling rate has an important influence on the spheroidal carbide under the same chemical composition condition.展开更多
Low carbon agriculture is a new production mode of green agriculture development to face the challenge of the global climate change, and a kind of innovation on developing circular agriculture. Up to now, low carbon a...Low carbon agriculture is a new production mode of green agriculture development to face the challenge of the global climate change, and a kind of innovation on developing circular agriculture. Up to now, low carbon agricultural development approaches are lacking of deep and systematical researches. Therefore, the paper briefly analyzed the situation and the existing problems of China's low carbon agricultural development, and then put forward the approaches to promote the low carbon agricultural development.展开更多
In order to understand the effects of titanium,zirconium and magnesium on inclusions and the impact toughness of heat affected zone(HAZ) of steel,four low carbon steels deoxidized by titanium,zirconium and magnesium...In order to understand the effects of titanium,zirconium and magnesium on inclusions and the impact toughness of heat affected zone(HAZ) of steel,four low carbon steels deoxidized by titanium,zirconium and magnesium were obtained.After melting,forging,rolling and welding simulation,the inclusion characteristics (size,distribution,morphology and chemistry) analysis,Charpy-type test and the fracture observation of the specimens after the Charpy-type test were carried out respectively.The following results were found.A linear relationship exists between inclusions density and Ti content when Ti content ranges from 0.004%to 0.032% without Mg,and the proportion of inclusions in diameter less than 0.5μm decreases with the increasing of Ti content in steel.The density of inclusion increases rapidly when adding Ti-Zr-Mg deoxidant.The addition of Ti-Zr-Mg can enhance the impact toughness of HAZ after welding simulation.The maximal impacting energy after welding simulation is 249 J at 253 K.The complex particles of MgO-ZrO2-TiOx-MnS are most benefit to enhance impact toughness.展开更多
<正>Copper and sulfur are typical residual elements or impurity elements in steel.Sufficient removal of them during steelmaking process is difficult for copper and costly for sulfur.Utilization of copper and sul...<正>Copper and sulfur are typical residual elements or impurity elements in steel.Sufficient removal of them during steelmaking process is difficult for copper and costly for sulfur.Utilization of copper and sulfur in steel, especially in steel scrap,has been an important issue for a long period for metallurgists.Copper and sulfur may combine to form copper sulfide,which may provide a prospect to avoid the detrimental effects of copper and sulfur in steel.Unfortunately the formation mechanism of copper sulfide in steel has not been completely clarified so far. In the present paper,solution treatment of samples containing copper and sulfur are firstly performed at 1623 K for 2.7×10~3 s followed by quenching into water.The samples are then isothermally heat-treated at 673 K,873 K, 1073 K,1273 K and 1373K for different time followed by quenching into water again.The size,morphology, constituent and crystallography of sulfide precipitates in these samples are investigated by scanning electron microscope(SEM) and TEM equipped with EDS.Fine copper sulfides(less than 100 nm) are observed to coexist with silicon oxide in samples even isothermally heat-treated at 1 373 K for 1.44×10~4 s;Film-like copper sulfides are generally observed to co-exist with iron sulfide in all samples;Plate-like copper sulfides are observed especially in sample isothermally heat-treated at 1 073 K for 1.44×10~4 s.The formation mechanisms of these copper sulfides have been discussed.展开更多
With urban economic growth,the urban ecological and environmental pollution is deteriorating. In turn,ecological and environmental pollution restricts urban economic growth. To realize coordinated development of urban...With urban economic growth,the urban ecological and environmental pollution is deteriorating. In turn,ecological and environmental pollution restricts urban economic growth. To realize coordinated development of urban economic growth and urban ecological environment,it is recommended to vigorously develop low carbon economy. On the basis of basic situations of ecological and environmental pollution in Jiangxi Province,following the connotation and development principle of the low carbon economy,this paper discussed ideas of ecological and environmental protection in Jiangxi Province,to lay a solid foundation for better promoting social and economic growth.展开更多
Initial process is influenced by substrate microstructure according to the study of initial stage of electroless plating on low carbon steel and pure iron. For low carbon steels, depositing on cementite is prior to th...Initial process is influenced by substrate microstructure according to the study of initial stage of electroless plating on low carbon steel and pure iron. For low carbon steels, depositing on cementite is prior to that on ferrite, and for pure iron, the grain boundaries and some favourable grains are deposited more easily. The initial reactions of electroless depositing of Ni-P alloy have been tentatively展开更多
In Jilin Province,China,economic development,high output and rational use of resources have become a pair of unrelieved contradictions.The coupling of eco-environmental and socioeconomic systems is not a simple linear...In Jilin Province,China,economic development,high output and rational use of resources have become a pair of unrelieved contradictions.The coupling of eco-environmental and socioeconomic systems is not a simple linear addition of these two systems to form an advanced composite system.Therefore,the analysis of the coupling degree between ecological environment and socioeconomic system from the perspective of dissociative structure can be expressed through the establishment of a system coupling model to express the relationship between the two systems.On this basis,a series of analytical indicators are constructed to quantitatively evaluate and qualitatively analyse the coupling between ecological environment and socioeconomy.展开更多
Currently urban issues show a dramatically increasing rely on auto use,which seriously affects the sustainable development of the city and makes how to build low-carbon cities become one of the urgent problems to be s...Currently urban issues show a dramatically increasing rely on auto use,which seriously affects the sustainable development of the city and makes how to build low-carbon cities become one of the urgent problems to be solved in the process of urban development.Therefore,low-carbon cities have become principles for China’s next generation of growth and the research hot spot of urban traffic planning.By taking a look at the concepts such as Compact City,transit-oriented development(TOD)city and‘small block’zoning,the article combined the relationship between urban spatial layout patterns and traffic development mode to build a green,low-carbon and sustainable urban development model.Finally,taking the urban design of the new district in the east of Handan City as an example,this research applied the concepts and approaches to planning practice,hoping to provide reference for building low carbon cities.展开更多
Realizing “carbon peaking” and “carbon neutrality” is a major strategic decision made by China to coordinate domestic and international situations.In order to achieve the “double carbon” goal,it is also necessar...Realizing “carbon peaking” and “carbon neutrality” is a major strategic decision made by China to coordinate domestic and international situations.In order to achieve the “double carbon” goal,it is also necessary for relevant practitioners to actively put into practice to improve the participation of residents and advocate low carbon life while formulating the policy action plan.Community is an important place for human activities and one of the main spatial types of carbon emissions in cities.Doing a good job in planning energy conservation and emission reduction in the community plays an important role in achieving the “double carbon” goal.Through the analysis of classic low carbon community practice cases at home and abroad,6 planning and design methods for low carbon community are concluded,and the development status of low carbon community in China is reflected and summarized.展开更多
文摘Dry sliding friction and wear test of Nb containing low carbon microalloyed steel was carried out at room temperature,and the effect of Nb on the wear behavior of the steel,as welll as the mechanism was studied.Scanning electron microscopy(SEM) and energy dispersive spectrometry(EDS) were employed to analyze the morphology and composition of the worn surface,and the structure evolution of the plastic deformation layer.The carbide content and type in the steel were analyzed by the electrolytic extraction device and X-ray diffraction(XRD).The experimental results demonstrate that the addition of 0.2% Nb can refine the grain and generate Nb C to improve the wear resistance of the steel.By enhancing the load and speed of wear experiment,the wear mechanism of the test steel with 0.2% Nb changes from slight oxidation wear to severe adhesion wear and oxidation wear.Compared with the load,the increase in the rotation speed exerts a greater influence on the wear of the test steel.
基金supported by“Key Technology Research on Operational Performance Improvement of the Green Building”(2020YFS0060)Key Project of Science and Technology Department of Sichuan Province+2 种基金supported by“Creative VR Teaching and Learning Research Based on‘PBL+’and Multidimensional Collaboration”(JG2021-721)“Reform in the Mode and Practice of Architecture Education with the Characteristics of Geology”(JG2021-672)Education Quality and Teaching Reform Project of Higher Education in Sichuan Province in 2021–2023.
文摘The construction of relevant standards for building carbon emission assessment in China has just started,and the quantitative analysis method and evaluation system are still imperfect,which hinders the development of low-carbon building design.Therefore,the use of intelligent energy management system is very necessary.The purpose of this paper is to explore the design optimization of low-carbon buildings based on intelligent energy management systems.Based on the proposed quantitative method of building carbon emission,this paper establishes the quota theoretical system of building carbon emission analysis,and develops the quota based carbon emission calculation software.Smart energy management system is a low-carbon energy-saving system based on the reference of large-scale building energy-saving system and combined with energy consumption.It provides a fast and effective calculation tool for the quantitative evaluation of carbon emission of construction projects,so as to realize the carbon emission control and optimization in the early stage of architectural design and construction.On this basis,the evaluation,analysis and calculation method of building structure based on carbon reduction target is proposed,combined with the carbon emission quota management standard proposed in this paper.Taking small high-rise residential buildings as an example,this paper compares and analyzes different building structural systems from the perspectives of structural performance,economy and carbon emission level.It provides a reference for the design and evaluation of low-carbon building structures.The smart energy management system collects user energy use parameters.It uses time period and time sequence to obtain a large amount of data for analysis and integration,which provides users with intuitive energy consumption data.Compared with the traditional architectural design method,the industrialized construction method can save 589.22 megajoules(MJ)per square meter.Based on 29270 megajoules(MJ)per ton of standard coal,the construction area of the case is about 8000 m2,and the energy saving of residential buildings is 161.04 tons of standard coal.This research is of great significance in reducing the carbon emission intensity of buildings.
基金Sponsored by General Project of Natural Science Foundation of Beijing City(8202017)Youth Talent Support Program of 2018 Beijing Municipal University Academic Human Resources Development(PXM2018_014212_000043).
文摘Low carbon landscape development is an emerging approach of landscape design,which aims to promote sustainable development,and reduce energy consumption and environmental impact by reducing carbon emissions.As an important component of low carbon landscape construction,the construction of urban pocket park system based on mini-parks plays a crucial role in improving the urban greening level,increasing the urban green space,alleviating the urban pressure,improving the living and healthy environment of urban residents,and promoting the urban ecological balance.Taking Chaowai district of Beijing as an example,this paper calculates the ecological value of trees including energy contribution,carbon sequestration,ability to improve rainfall runoff and aesthetic value by collecting the information of trees and the plot on which the trees are located through the i-Tree platform,which provides important reference value for the urban pocket park system planning to create low carbon comprehensive benefits.
文摘Considering the growing prominence of global environmental issues,a low-carbon economy has emerged as a crucial direction for economic development across various countries.As the world’s second-largest economy,China has also witnessed the influence of a low-carbon economy on its international trade development.This article aims to commence with an exploration of the development background,meaning,and significance of a low-carbon economy.Subsequently,it delves into an in-depth analysis of the impact that a low-carbon economy has on China’s international trade.The article concludes by proposing pertinent countermeasures and suggestions.
文摘With the continuous implementation of national measures related to carbon neutrality strategy,the concept of a low-carbon economy has been deeply rooted in people’s hearts.Low-carbon tourism has gradually become an inevitable trend,and the tourism industry is also undergoing orderly transformation and upgrading.To promote the sustainable development of the tourism industry,the tourism and hotel industry should also shift towards a low-carbon and green model.Hotel activities can easily bring related environmental issues,such as energy consumption,garbage generation,ecological pollution,etc.Therefore,building a green hotel will bring huge social and economic benefits to the low-carbon tourism industry.This article will address the above issues and take a low-carbon economy as the starting point,proposing sustainable development strategies and suggestions for green hotels from both the internal and external environment of the hotel,creating a low-carbon management atmosphere,and promoting the low-carbon operation of the green hotel industry.
基金financially supported by the National Natural Science Foundation of China (No.U1960202)the China Post-doctoral Science Foundation funded Projects (No.2019M651467)the Natural Science Foundation Joint Fund Project of Liaoning Province, China (No.2019-KF-2506)。
文摘The impact energy prediction model of low carbon steel was investigated based on industrial data. A three-layer neural network, extreme learning machine, and deep neural network were compared with different activation functions, structure parameters, and training functions. Bayesian optimization was used to determine the optimal hyper-parameters of the deep neural network. The model with the best performance was applied to investigate the importance of process parameter variables on the impact energy of low carbon steel. The results show that the deep neural network obtains better prediction results than those of a shallow neural network because of the multiple hidden layers improving the learning ability of the model. Among the models, the Bayesian optimization deep neural network achieves the highest correlation coefficient of 0.9536, the lowest mean absolute relative error of 0.0843, and the lowest root mean square error of 17.34 J for predicting the impact energy of low carbon steel. Among the variables, the main factors affecting the impact energy of low carbon steel with a final thickness of7.5 mm are the thickness of the original slab, the thickness of intermediate slab, and the rough rolling exit temperature from the specific hot rolling production line.
基金supported by scientific research project of Zhejiang Provincial Education Department(Grant No.Y20112088,China)Science and technology project of Zhejiang Province(Grant No.2011R09028-10,China)
文摘A series of self-reducing bifunctional Ni-W/SBA-15 catalysts were synthesized using biomass-based carbon source as the reducing agent without conventional further reduction step. The self-reducing catalysts were performed on the hydrogenolysis of cellulose to low carbon polyols. The effects of calcination temperature and metallic loading contents for cellulose hydrogenolysis reaction were investigated detailedly.The optimal calcination temperature was found to be 673 K by TG analysis. The active metal nanoparticles with a better dispersion were observed using SEM and element mapping technology. The yield of low carbon polyols using the catalyst with the receipt of 10%Ni-15%W/SBA-15-673 K can reach as high as68.14%, of which the ethylene glycol(EG) accounts for 61.04%.
文摘On the basis of the concept and characteristics of circular economy, this paper analyzes the restraining factors of China's circular agricultural development as follows: issues concerning agriculture, countryside and farmers are outstanding; the problems of agricultural resources and agricultural ecological environment are serious; the quality of agricultural products cannot meet the demand of domestic and international market for food. Based on the internal requirements of low carbon economic development, this paper advances four innovative models concerning China's circular agricultural development as follows: the model of combining planting and breeding of agriculture, the developmental model of leisure and sightseeing, ecological integration model, and the developmental model of reusing agricultural byproducts. Every region should choose or create different circular agricultural model in different domains, in order to better use agricultural resources, reduce the consumption of agricultural energy inputs, reduce the emission of agricultural greenhouse gas, develop low carbon agriculture, and make great contribution for meeting the international challenges and promoting China's agricultural development.
文摘This work intends to provide a comprehensive review on the development of Al_(2)O_(3)-C refractories with low/ultra-low carbon content.It covers three parts:carbon materials,microstructure optimization of the refractory matrix by ceramic phases,and application of metal Al as raw material.Carbon black,expanded graphite,and ultrafine microcrystalline graphite,as price-competitive carbon materials,can be chosen to prepare the low-carbon Al_(2)O_(3)-C refractories after some special treatment.Ni/Co/Fe-catalyzed phenolic resin contributes to improving the properties of the low-carbon Al_(2)O_(3)-C refractories.The performance deterioration of the low-carbon Al_(2)O_(3)-C refractories can also be improved by in-situ formed or pre-synthesized ceramic phases.Metal Al,characterized by plasticity forming,acceleration of sintering,oxidation resistance,and high reactivity,can be used as raw materials to completely replace graphite,and the prepared resin bonded Al-Al_(2)O_(3)based refractories are one novel development direction of the ultra-low carbon Al_(2)O_(3)-C refractories.
基金Sponsored by the Major State Basic Research Development Program of China(Grant No.2010CB630801)
文摘The low carbon Nb-Ti microalloyed tested steel was prepared by the process of vacuum induction furnace smelting,forging and hot rolling.The new steel aims to meet the demand of high strength,high toughness and high plasticity for building facilities.The effects of quenching process on microstructure and mechanical properties of tested steel were investigated.The results showed that prior austenite grain size,phase type and precipitation behavior of(Nb,Ti)(C,N)play important roles in mechanical properties of the steel.Through modified appropriately,the model of austenite grain growth during heating and holding is d^(5.7778)=5.6478^(5.7778)+7.04×10^(22)t^(1.6136)exp(-427.15×10~3/(RT)).The grain growth activation energy is Q_g=427.15 kJ.During quenching,the microscopic structures are mainly martensite and lath bainite which contains lots of lath substructure and dislocations.The content of phases,fine and coarsening(Nb,Ti)(C,N)precipitated changes during different quenching temperatures and holding time.Finally compared with the hardness value,the best quenching process can be obtained that heating temperature and holding time are900℃and 50 mins,respectively.
基金the China Postdoctoral Science Foundation(2019M650725)Shenzhen Low Carbon City Big Data Engineering Laboratory(ShenzhneDRC[2017]1089)Discipline Construction Program on Combating Climate Change and Low Carbon Economics of the Harbin Institute of Technology,Shenzhen,China(ShenzhenDRC[2018]725).
文摘This study develops a comprehensive analysis framework and socio-economic energy system model that interlinks demographic change and energy system in order to analyze the urbanization process and its relation with China's long-term CO2 emissions trend as China'economy enters the“new normal”stage.The results show that,around 300 million people are expected to migrate from rural areas to urban areas by 2050 following a trend,in which people are moving gradually from small and medium city groups to large and super city groups.The migration trend together with the improvement in living standard will promote China's infrastructure construction,industry production,and energy service demand growth.Under the Business as Usual(BAU)scenario,total primary energy consumption in China will reach 8.4 Gtce by 2050,energyrelated CO2 emissions will increase to 17.6 Gt,which is 83%higher than the 2013 level.While in the Low Carbon Transition(LCT)scenario with technology innovation,the total primary energy demand for China in 2050 could be controlled at^6 Gtce;CO2 emissions would peak during 2020—2025,and be reduced by 78%by 2050 compared to the BAU scenario.In the transition process,non-fossil fuel power generation and energy efficiency technologies have the largest mitigation potentials.Industry and power sectors would peak first before 2020,followed by the building and transport sectors which are projected to peak around 2030.The total additional capital investment required for LCT would account for 1.5%of GDP.Therefore,it is technologically and economically feasible for China to implement new urbanization strategy.
基金financially supported by the Hebei Province Science and Technology Support Program(No.14211007D)
文摘The formation mechanism of the spheroidal carbide in the ultra-low carbon ductile cast iron fabricated by the metal mold casting technique was systematically investigated. The results demonstrated that the spheroidal carbide belonged to eutectic carbide and crystallized in the isolated eutectic liquid phase area. The formation process of the spheroidal carbide was related to the contact and the intersection between the primary dendrite and the secondary dendrite of austenite. The oxides of magnesium, rare earths and other elements can act as heterogeneous nucleation sites for the spheroidal carbide. It was also found that the amount of the spheroidal carbide would increase with an increase in carbon content. The cooling rate has an important influence on the spheroidal carbide under the same chemical composition condition.
文摘Low carbon agriculture is a new production mode of green agriculture development to face the challenge of the global climate change, and a kind of innovation on developing circular agriculture. Up to now, low carbon agricultural development approaches are lacking of deep and systematical researches. Therefore, the paper briefly analyzed the situation and the existing problems of China's low carbon agricultural development, and then put forward the approaches to promote the low carbon agricultural development.
文摘In order to understand the effects of titanium,zirconium and magnesium on inclusions and the impact toughness of heat affected zone(HAZ) of steel,four low carbon steels deoxidized by titanium,zirconium and magnesium were obtained.After melting,forging,rolling and welding simulation,the inclusion characteristics (size,distribution,morphology and chemistry) analysis,Charpy-type test and the fracture observation of the specimens after the Charpy-type test were carried out respectively.The following results were found.A linear relationship exists between inclusions density and Ti content when Ti content ranges from 0.004%to 0.032% without Mg,and the proportion of inclusions in diameter less than 0.5μm decreases with the increasing of Ti content in steel.The density of inclusion increases rapidly when adding Ti-Zr-Mg deoxidant.The addition of Ti-Zr-Mg can enhance the impact toughness of HAZ after welding simulation.The maximal impacting energy after welding simulation is 249 J at 253 K.The complex particles of MgO-ZrO2-TiOx-MnS are most benefit to enhance impact toughness.
文摘<正>Copper and sulfur are typical residual elements or impurity elements in steel.Sufficient removal of them during steelmaking process is difficult for copper and costly for sulfur.Utilization of copper and sulfur in steel, especially in steel scrap,has been an important issue for a long period for metallurgists.Copper and sulfur may combine to form copper sulfide,which may provide a prospect to avoid the detrimental effects of copper and sulfur in steel.Unfortunately the formation mechanism of copper sulfide in steel has not been completely clarified so far. In the present paper,solution treatment of samples containing copper and sulfur are firstly performed at 1623 K for 2.7×10~3 s followed by quenching into water.The samples are then isothermally heat-treated at 673 K,873 K, 1073 K,1273 K and 1373K for different time followed by quenching into water again.The size,morphology, constituent and crystallography of sulfide precipitates in these samples are investigated by scanning electron microscope(SEM) and TEM equipped with EDS.Fine copper sulfides(less than 100 nm) are observed to coexist with silicon oxide in samples even isothermally heat-treated at 1 373 K for 1.44×10~4 s;Film-like copper sulfides are generally observed to co-exist with iron sulfide in all samples;Plate-like copper sulfides are observed especially in sample isothermally heat-treated at 1 073 K for 1.44×10~4 s.The formation mechanisms of these copper sulfides have been discussed.
文摘With urban economic growth,the urban ecological and environmental pollution is deteriorating. In turn,ecological and environmental pollution restricts urban economic growth. To realize coordinated development of urban economic growth and urban ecological environment,it is recommended to vigorously develop low carbon economy. On the basis of basic situations of ecological and environmental pollution in Jiangxi Province,following the connotation and development principle of the low carbon economy,this paper discussed ideas of ecological and environmental protection in Jiangxi Province,to lay a solid foundation for better promoting social and economic growth.
文摘Initial process is influenced by substrate microstructure according to the study of initial stage of electroless plating on low carbon steel and pure iron. For low carbon steels, depositing on cementite is prior to that on ferrite, and for pure iron, the grain boundaries and some favourable grains are deposited more easily. The initial reactions of electroless depositing of Ni-P alloy have been tentatively
基金Sponsored by Jilin Province Higher Education Scientific Research Subject (JGJX2020D583)。
文摘In Jilin Province,China,economic development,high output and rational use of resources have become a pair of unrelieved contradictions.The coupling of eco-environmental and socioeconomic systems is not a simple linear addition of these two systems to form an advanced composite system.Therefore,the analysis of the coupling degree between ecological environment and socioeconomic system from the perspective of dissociative structure can be expressed through the establishment of a system coupling model to express the relationship between the two systems.On this basis,a series of analytical indicators are constructed to quantitatively evaluate and qualitatively analyse the coupling between ecological environment and socioeconomy.
基金Training Project of School of Architecture and Art,Hebei University of Engineering(2020-KJZD-001).
文摘Currently urban issues show a dramatically increasing rely on auto use,which seriously affects the sustainable development of the city and makes how to build low-carbon cities become one of the urgent problems to be solved in the process of urban development.Therefore,low-carbon cities have become principles for China’s next generation of growth and the research hot spot of urban traffic planning.By taking a look at the concepts such as Compact City,transit-oriented development(TOD)city and‘small block’zoning,the article combined the relationship between urban spatial layout patterns and traffic development mode to build a green,low-carbon and sustainable urban development model.Finally,taking the urban design of the new district in the east of Handan City as an example,this research applied the concepts and approaches to planning practice,hoping to provide reference for building low carbon cities.
基金Sponsored by General Project of Natural Science Foundation of Beijing (8202017)Youth Talent Support Program of 2018 Beijing Municipal University Academic Human Resources Development (PXM2018_014212_000043)。
文摘Realizing “carbon peaking” and “carbon neutrality” is a major strategic decision made by China to coordinate domestic and international situations.In order to achieve the “double carbon” goal,it is also necessary for relevant practitioners to actively put into practice to improve the participation of residents and advocate low carbon life while formulating the policy action plan.Community is an important place for human activities and one of the main spatial types of carbon emissions in cities.Doing a good job in planning energy conservation and emission reduction in the community plays an important role in achieving the “double carbon” goal.Through the analysis of classic low carbon community practice cases at home and abroad,6 planning and design methods for low carbon community are concluded,and the development status of low carbon community in China is reflected and summarized.