The microbial community structures in an integrated two-phase anaerobic reactor（ITPAR）were investigated by 16 S r DNA clone library technology. The 75 L reactor was designed with a 25 L rotating acidogenic unit at t...The microbial community structures in an integrated two-phase anaerobic reactor（ITPAR）were investigated by 16 S r DNA clone library technology. The 75 L reactor was designed with a 25 L rotating acidogenic unit at the top and a 50 L conventional upflow methanogenic unit at the bottom, with a recirculation connected to the two units. The reactor had been operated for 21 stages to co-digest fruit/vegetable wastes and wheat straw, which showed a very good biogas production and decomposition of cellulosic materials. The results showed that many kinds of cellulose and glycan decomposition bacteria related with Bacteroidales,Clostridiales and Syntrophobacterales were dominated in the reactor, with more bacteria community diversities in the acidogenic unit. The methanogens were mostly related with Methanosaeta, Methanosarcina, Methanoculleus, Methanospirillum and Methanobacterium; the predominating genus Methanosaeta, accounting for 40.5%, 54.2%, 73.6% and 78.7% in four samples from top to bottom, indicated a major methanogenesis pathway by acetoclastic methanogenesis in the methanogenic unit. The beta diversity indexes illustrated a more similar distribution of bacterial communities than that of methanogens between acidogenic unit and methanogenic unit. The differentiation of methanogenic community composition in two phases, as well as pH values and volatile fatty acid（VFA） concentrations confirmed the phase separation of the ITPAR. Overall, the results of this study demonstrated that the special designing of ITPAR maintained a sufficient number of methanogens, more diverse communities and stronger syntrophic associations among microorganisms, which made two phase anaerobic digestion of cellulosic materials more efficient.展开更多
A water model with a geometric similarity ratio of 1：5 was developed to investigate the gas-liquid mass transfer and flow charac- teristics in a Peirce-Smith converter. A gas mixture of CO2 and Ar was injected into a...A water model with a geometric similarity ratio of 1：5 was developed to investigate the gas-liquid mass transfer and flow charac- teristics in a Peirce-Smith converter. A gas mixture of CO2 and Ar was injected into a NaOH solution bath. The flow field, volumetric mass transfer coefficient per unit volume （Ak/V; where A is the contact area between phases, V is the volume, and k is the mass transfer coeffi- cient）, and gas utilization ratio （t/） were then measured at different gas flow rates and blow angles. The results showed that the flow field could be divided into five regions, i.e., injection, strong loop, weak loop, splashing, and dead zone. Whereas the Ak/V of the bath increased and then decreased with increasing gas flow rate, and n steadily increased. When the converter was rotated clockwise, both Ak/F and t/increased. However, the flow condition deteriorated when the gas flow rate and blow angle were drastically increased. Therefore, these para- meters must be controlled to optimal conditions. In the proposed model, the optimal gas flow rate and blow angle were 7.5 m3.h-1 and 10°, respectively.展开更多
A numerical model was established to simulate the flow field in a Peirce–Smith converter bath, which is extensively adopted in copper making. The mean phase and velocity distribution, circular area, and mean wall she...A numerical model was established to simulate the flow field in a Peirce–Smith converter bath, which is extensively adopted in copper making. The mean phase and velocity distribution, circular area, and mean wall shear stress were calculated to determine the optimal operation parameter of the converter. The results showed that the slag phase gathered substantially in the dead zone. The circular flow was promoted by increasing the gas flow rate, Q, and decreasing the nozzle height, h. However, these operations significantly aggravate the wall shear stress. Reducing the nozzle diameter, d, increases the injection velocity, which may accelerate the flow field. However, when the nozzle diameter has an interval design, the bubble behaviors cannot be combined, thus, weakening the injection efficiency. Considering the balance between the circular flow and wall shear stress in this model, the optimal operation parameters were Q = 30000–35000 m^3/h, h = 425–525 mm, and d = 40 & 50 mm.展开更多
We constructed a 1：10 cold water experimental model by geometrically scaling down an Isa smelting furnace. The mixing processes at different liquid heights, lance diameters, lance submersion depths, and gas flow rate...We constructed a 1：10 cold water experimental model by geometrically scaling down an Isa smelting furnace. The mixing processes at different liquid heights, lance diameters, lance submersion depths, and gas flow rates were subsequently measured using the conductivity method. A new criterion was proposed to determine the mixing time. On this basis, the quasi-equations of the mixing time as a function of different parameters were established. The parameters of the top-blown smelting process were optimized using high-speed photography. An excessively high gas flow rate or excessively low liquid height would enhance the fluctuation and splashing of liquid in the bath, which is unfavorable for material mixing. Simultaneously increasing the lance diameter and the lance submersion depth would promote the mixing in the bath, thereby improving the smelting efficiency.展开更多
China’s coastal wetlands provide breeding,migration stopover,and wintering habitats for about 230 waterbird species,which is more than a quarter of all waterbirds in the world.Large-scale and high intensity human act...China’s coastal wetlands provide breeding,migration stopover,and wintering habitats for about 230 waterbird species,which is more than a quarter of all waterbirds in the world.Large-scale and high intensity human activities have resulted in serious loss and degradation of coastal wetlands over the past half century,causing population declines in many waterbirds.Through a literature review and expert surveys,this article reviews conservation measures taken in recent decades to protect waterbirds in China’s coastal wetlands and provides recommendations for future conservation action from three aspects:policy and administration,habitat conservation and management,and multiparty participation.Over the past decades,many conservation legislation,regulations and action plans at the national level and more site-specific measures and interventions have been implemented,with notable improvement in the effectiveness in policy making and multi-stakeholder participation.Accordingly,some threats to waterbirds have been mitigated and many key sites for waterbirds have been designated as strictly protected nature reserves.However,some critical issues still remain,mostly related to habitat conservation and management,such as coastal wetland restoration,control of invasive Spartina alterniflora,control of environmental pollution,and improvement of artificial habitat quality.We highlight that protecting natural tidal wetlands and improving habitat quality are critical for the conservation of coastal waterbirds,especially those highly dependent on the intertidal wetlands.China has demonstrated strong commitment to ecological conservation and restoration for the future,in terms of both funding and policies for biodiversity and wetland ecosystems.It is important that this commitment to conserve coastal waterbirds is supported continuously by science-and evidence-based decisions and actions.展开更多
Based on the revised reduction models of the 14 low-carbon ICT solutions from Chongqing Mobile of the China Mobile Group,the CO2e emission reduction brought about by low-carbon ICTs of the wireless telecom sector of C...Based on the revised reduction models of the 14 low-carbon ICT solutions from Chongqing Mobile of the China Mobile Group,the CO2e emission reduction brought about by low-carbon ICTs of the wireless telecom sector of Chongqing Mobile,the entire China Mobile Group and the whole China in 2009 is calculated.And then the CO2e emission reduction potentials in 2010,2020 and 2030 are calculated in four main important fields of China,i.e.,intelligent transportation,dematerialization,smart work and smart appliances.The ICTs in the telecom sector are mostly dedicated to these fields.It provides a valuable insight into future reduction targets that should be set up for China.展开更多
Producing renewable e-methanol from e-hydrogen and diverse carbon sources is an essential way for clean methanol preparation.Despite this,the technical and economic feasibility of different e-methanols has yet to be t...Producing renewable e-methanol from e-hydrogen and diverse carbon sources is an essential way for clean methanol preparation.Despite this,the technical and economic feasibility of different e-methanols has yet to be thoroughly compared,leaving the most promising pathway to achieve commercialization yet evident.This paper reports a preliminary analysis of the lifecycle greenhouse gas(GHG)emissions and costs of four renewable e-methanols with different carbon sources:bio-carbon,direct air capture(DAC),fossil fuel carbon capture(FFCC),and fossil.The results indicate that renewable e-methanol costs(4167−10250 CNY/tonne)2−4 times the market rate of grey methanol.However,with the carbon tax and the projected decline in e-H2 costs,blue e-methanol may initially replace diesel in inland navigation,followed by a shift from heavy fuel oil(HFO)to green e-methanol in ocean ship-ping.Furthermore,the e-H2 cost and the availability of green carbon are vital factors affecting cost-effectiveness.A reduction in e-H2 cost from 2.1 CNY/Nm3 to 1.1 CNY/Nm3 resulting from a transition from an annual to a daily scheduling period,could lower e-methanol costs by 1200 to 2100 CNY.This paper also provides an in-depth discussion on the challenges and opportunities associated with the various green carbon sources.展开更多
I Unstable situation brings concerns about international capital flows in China. International capital flows refers to the country-to-country or region-to-region movement of capital.It consists of the inflow and outfl...I Unstable situation brings concerns about international capital flows in China. International capital flows refers to the country-to-country or region-to-region movement of capital.It consists of the inflow and outflow of capital in the form of FDI,FPI,international borrowing展开更多
This paper elaborates on the key points of the latest developments in methane emissions reduction policies in the European Union(EU)and the United States(U.S.)and makes a comparative analysis of their policy framework...This paper elaborates on the key points of the latest developments in methane emissions reduction policies in the European Union(EU)and the United States(U.S.)and makes a comparative analysis of their policy frameworks.There are similarities between the EU and the U.S.in terms of methane emissions reduction measures,but there are also significant differences.For instance,the EU has proposed requirements for fossil energy imports,placing greater emphasis on the role of international organizations.On the basis of comparative analysis,this paper presents insights for China from the perspectives of the target,policy,data,emission reduction path,utilization as energy,and international influence.展开更多
Forestation is important for sequestering atmospheric carbon,and it is a cost-effective and nature-based solution(NBS)for mitigating global climate change.Here,under the assumption of forestation in the potential plan...Forestation is important for sequestering atmospheric carbon,and it is a cost-effective and nature-based solution(NBS)for mitigating global climate change.Here,under the assumption of forestation in the potential plantable lands,we used the forest carbon sequestration(FCS)model and field survey involving 3365 forest plots to assess the carbon sequestration rate(CSR)of Chinese existing and new forestation forests from 2010 to 2060 under three forestation and three climate scenarios.Without considering the influence of extreme events and human disturbance,the estimated average CSR in Chinese forests was 0.358±0.016 Pg C a^(-1),with partitioning to biomass(0.211±0.016 Pg C a^(-1))and soil(0.147±0.005 Pg C a^(-1)),respectively.The existing forests account for approximately 93.5%of the CSR,which will peak near 2035,and decreasing trend was present overall after 2035.After 2035,effective tending management is required to maintain the high CSR level,such as selective cutting,thinning,and approximate disturbance.However,new forestation from 2015 in the potential plantable lands would play a minimal role in additional CSR increases.In China,the CSR is generally higher in the Northeast,Southwest,and Central-South,and lower in the Northwest.Considering the potential losses through deforestation and logging,it is realistically estimated that CSR in Chinese forests would remain in the range of 0.161–0.358 Pg C a^(-1) from 2010 to 2060.Overall,forests have the potential to offset 14.1%of the national anthropogenic carbon emissions in China over the period of 2010–2060,significantly contributing to the carbon neutrality target of 2060 with the implementation of effective management strategies for existing forests and expansion of forestation.展开更多
Chu Xiuan(Jon-Jon),Chu Xiuzhen(Susan)andChen Ziwen(June),from the Guilin Orphan-age look just like three normal toddlers,butthese three orphans were all sentenced to an early death.All three suffered from a life-threa...Chu Xiuan(Jon-Jon),Chu Xiuzhen(Susan)andChen Ziwen(June),from the Guilin Orphan-age look just like three normal toddlers,butthese three orphans were all sentenced to an early death.All three suffered from a life-threatening heart defect.展开更多
基金supported by the Major Science and Technology Programs for Water Pollution Control and Management of China(No.2012ZX07205-001)the National Science and Technology Support Program(No.2008BADC4B18)
文摘The microbial community structures in an integrated two-phase anaerobic reactor（ITPAR）were investigated by 16 S r DNA clone library technology. The 75 L reactor was designed with a 25 L rotating acidogenic unit at the top and a 50 L conventional upflow methanogenic unit at the bottom, with a recirculation connected to the two units. The reactor had been operated for 21 stages to co-digest fruit/vegetable wastes and wheat straw, which showed a very good biogas production and decomposition of cellulosic materials. The results showed that many kinds of cellulose and glycan decomposition bacteria related with Bacteroidales,Clostridiales and Syntrophobacterales were dominated in the reactor, with more bacteria community diversities in the acidogenic unit. The methanogens were mostly related with Methanosaeta, Methanosarcina, Methanoculleus, Methanospirillum and Methanobacterium; the predominating genus Methanosaeta, accounting for 40.5%, 54.2%, 73.6% and 78.7% in four samples from top to bottom, indicated a major methanogenesis pathway by acetoclastic methanogenesis in the methanogenic unit. The beta diversity indexes illustrated a more similar distribution of bacterial communities than that of methanogens between acidogenic unit and methanogenic unit. The differentiation of methanogenic community composition in two phases, as well as pH values and volatile fatty acid（VFA） concentrations confirmed the phase separation of the ITPAR. Overall, the results of this study demonstrated that the special designing of ITPAR maintained a sufficient number of methanogens, more diverse communities and stronger syntrophic associations among microorganisms, which made two phase anaerobic digestion of cellulosic materials more efficient.
基金financially supported by the National Natural Science Foundation of China(No.51504018)the China Postdoctoral Science Foundation(2015M580986)the Fundamental Research Funds for the Central Universities(FRF-TP-17-038A2)
文摘A water model with a geometric similarity ratio of 1：5 was developed to investigate the gas-liquid mass transfer and flow charac- teristics in a Peirce-Smith converter. A gas mixture of CO2 and Ar was injected into a NaOH solution bath. The flow field, volumetric mass transfer coefficient per unit volume （Ak/V; where A is the contact area between phases, V is the volume, and k is the mass transfer coeffi- cient）, and gas utilization ratio （t/） were then measured at different gas flow rates and blow angles. The results showed that the flow field could be divided into five regions, i.e., injection, strong loop, weak loop, splashing, and dead zone. Whereas the Ak/V of the bath increased and then decreased with increasing gas flow rate, and n steadily increased. When the converter was rotated clockwise, both Ak/F and t/increased. However, the flow condition deteriorated when the gas flow rate and blow angle were drastically increased. Therefore, these para- meters must be controlled to optimal conditions. In the proposed model, the optimal gas flow rate and blow angle were 7.5 m3.h-1 and 10°, respectively.
基金financially supported by the Guangxi Innovation-Driven Development Project (No.AA18242042-1)the National Natural Science Foundation of China (No.51504018)
文摘A numerical model was established to simulate the flow field in a Peirce–Smith converter bath, which is extensively adopted in copper making. The mean phase and velocity distribution, circular area, and mean wall shear stress were calculated to determine the optimal operation parameter of the converter. The results showed that the slag phase gathered substantially in the dead zone. The circular flow was promoted by increasing the gas flow rate, Q, and decreasing the nozzle height, h. However, these operations significantly aggravate the wall shear stress. Reducing the nozzle diameter, d, increases the injection velocity, which may accelerate the flow field. However, when the nozzle diameter has an interval design, the bubble behaviors cannot be combined, thus, weakening the injection efficiency. Considering the balance between the circular flow and wall shear stress in this model, the optimal operation parameters were Q = 30000–35000 m^3/h, h = 425–525 mm, and d = 40 & 50 mm.
基金financially supported by the National Natural Science Foundation of China(No.51504018)the China Postdoctoral Science Foundation(No.2015M580986)the Fundamental Research Funds for the Central Universities(No.FRF-TP-15-069A1)
文摘We constructed a 1：10 cold water experimental model by geometrically scaling down an Isa smelting furnace. The mixing processes at different liquid heights, lance diameters, lance submersion depths, and gas flow rates were subsequently measured using the conductivity method. A new criterion was proposed to determine the mixing time. On this basis, the quasi-equations of the mixing time as a function of different parameters were established. The parameters of the top-blown smelting process were optimized using high-speed photography. An excessively high gas flow rate or excessively low liquid height would enhance the fluctuation and splashing of liquid in the bath, which is unfavorable for material mixing. Simultaneously increasing the lance diameter and the lance submersion depth would promote the mixing in the bath, thereby improving the smelting efficiency.
基金financially supported by National Key Research and Development Program of China (2022YFF1301004)the National Natural Science Foundation of China (31830089 and 32170518)TP’s work in the East Asian-Australasian Flyway through Global Flyway Network was supported by WWF-Netherlands,the MAVA Foundation and many other benefactors
文摘China’s coastal wetlands provide breeding,migration stopover,and wintering habitats for about 230 waterbird species,which is more than a quarter of all waterbirds in the world.Large-scale and high intensity human activities have resulted in serious loss and degradation of coastal wetlands over the past half century,causing population declines in many waterbirds.Through a literature review and expert surveys,this article reviews conservation measures taken in recent decades to protect waterbirds in China’s coastal wetlands and provides recommendations for future conservation action from three aspects:policy and administration,habitat conservation and management,and multiparty participation.Over the past decades,many conservation legislation,regulations and action plans at the national level and more site-specific measures and interventions have been implemented,with notable improvement in the effectiveness in policy making and multi-stakeholder participation.Accordingly,some threats to waterbirds have been mitigated and many key sites for waterbirds have been designated as strictly protected nature reserves.However,some critical issues still remain,mostly related to habitat conservation and management,such as coastal wetland restoration,control of invasive Spartina alterniflora,control of environmental pollution,and improvement of artificial habitat quality.We highlight that protecting natural tidal wetlands and improving habitat quality are critical for the conservation of coastal waterbirds,especially those highly dependent on the intertidal wetlands.China has demonstrated strong commitment to ecological conservation and restoration for the future,in terms of both funding and policies for biodiversity and wetland ecosystems.It is important that this commitment to conserve coastal waterbirds is supported continuously by science-and evidence-based decisions and actions.
基金supported by National Natural Science Foundation of China under Grant No. 71001010Fundamental Research Funds for Central Universities under Grant No.2009RC1001
文摘Based on the revised reduction models of the 14 low-carbon ICT solutions from Chongqing Mobile of the China Mobile Group,the CO2e emission reduction brought about by low-carbon ICTs of the wireless telecom sector of Chongqing Mobile,the entire China Mobile Group and the whole China in 2009 is calculated.And then the CO2e emission reduction potentials in 2010,2020 and 2030 are calculated in four main important fields of China,i.e.,intelligent transportation,dematerialization,smart work and smart appliances.The ICTs in the telecom sector are mostly dedicated to these fields.It provides a valuable insight into future reduction targets that should be set up for China.
基金supported by the National Natural Science Foundation of China(U22A20220)the China Postdoctoral Science Foundation(2023M741887).
文摘Producing renewable e-methanol from e-hydrogen and diverse carbon sources is an essential way for clean methanol preparation.Despite this,the technical and economic feasibility of different e-methanols has yet to be thoroughly compared,leaving the most promising pathway to achieve commercialization yet evident.This paper reports a preliminary analysis of the lifecycle greenhouse gas(GHG)emissions and costs of four renewable e-methanols with different carbon sources:bio-carbon,direct air capture(DAC),fossil fuel carbon capture(FFCC),and fossil.The results indicate that renewable e-methanol costs(4167−10250 CNY/tonne)2−4 times the market rate of grey methanol.However,with the carbon tax and the projected decline in e-H2 costs,blue e-methanol may initially replace diesel in inland navigation,followed by a shift from heavy fuel oil(HFO)to green e-methanol in ocean ship-ping.Furthermore,the e-H2 cost and the availability of green carbon are vital factors affecting cost-effectiveness.A reduction in e-H2 cost from 2.1 CNY/Nm3 to 1.1 CNY/Nm3 resulting from a transition from an annual to a daily scheduling period,could lower e-methanol costs by 1200 to 2100 CNY.This paper also provides an in-depth discussion on the challenges and opportunities associated with the various green carbon sources.
文摘I Unstable situation brings concerns about international capital flows in China. International capital flows refers to the country-to-country or region-to-region movement of capital.It consists of the inflow and outflow of capital in the form of FDI,FPI,international borrowing
文摘This paper elaborates on the key points of the latest developments in methane emissions reduction policies in the European Union(EU)and the United States(U.S.)and makes a comparative analysis of their policy frameworks.There are similarities between the EU and the U.S.in terms of methane emissions reduction measures,but there are also significant differences.For instance,the EU has proposed requirements for fossil energy imports,placing greater emphasis on the role of international organizations.On the basis of comparative analysis,this paper presents insights for China from the perspectives of the target,policy,data,emission reduction path,utilization as energy,and international influence.
基金supported by the National Natural Science Foundation of China(31988102,32171544)the National Science and Technology Basic Resources Survey Program of China(2019FY101300)the Youth Innovation Research Project from Key Laboratory of Ecosystem Network Observation and Modeling,Chinese Academy of Sciences。
文摘Forestation is important for sequestering atmospheric carbon,and it is a cost-effective and nature-based solution(NBS)for mitigating global climate change.Here,under the assumption of forestation in the potential plantable lands,we used the forest carbon sequestration(FCS)model and field survey involving 3365 forest plots to assess the carbon sequestration rate(CSR)of Chinese existing and new forestation forests from 2010 to 2060 under three forestation and three climate scenarios.Without considering the influence of extreme events and human disturbance,the estimated average CSR in Chinese forests was 0.358±0.016 Pg C a^(-1),with partitioning to biomass(0.211±0.016 Pg C a^(-1))and soil(0.147±0.005 Pg C a^(-1)),respectively.The existing forests account for approximately 93.5%of the CSR,which will peak near 2035,and decreasing trend was present overall after 2035.After 2035,effective tending management is required to maintain the high CSR level,such as selective cutting,thinning,and approximate disturbance.However,new forestation from 2015 in the potential plantable lands would play a minimal role in additional CSR increases.In China,the CSR is generally higher in the Northeast,Southwest,and Central-South,and lower in the Northwest.Considering the potential losses through deforestation and logging,it is realistically estimated that CSR in Chinese forests would remain in the range of 0.161–0.358 Pg C a^(-1) from 2010 to 2060.Overall,forests have the potential to offset 14.1%of the national anthropogenic carbon emissions in China over the period of 2010–2060,significantly contributing to the carbon neutrality target of 2060 with the implementation of effective management strategies for existing forests and expansion of forestation.
文摘Chu Xiuan(Jon-Jon),Chu Xiuzhen(Susan)andChen Ziwen(June),from the Guilin Orphan-age look just like three normal toddlers,butthese three orphans were all sentenced to an early death.All three suffered from a life-threatening heart defect.
