The development of electrical engineering and electronic, communications, smart power grid, and ultra-high voltage transmission technologies have driven the energy system revolution to the next generation: the energy ...The development of electrical engineering and electronic, communications, smart power grid, and ultra-high voltage transmission technologies have driven the energy system revolution to the next generation: the energy internet. Progressive penetration of intermittent renewable energy sources into the energy system has led to unprecedented challenges to the currently wide use of coal-fired power generation technologies. Here, the applications and prospects of advanced coal-fired power generation technologies are analyzed. These technologies can be summarized into three categories:(1) large-scale and higher parameters coal-fired power generation technologies, including 620/650/700 oC ultra-supercritical thermal power and double reheat ultra-supercritical coal-fired power generation technologies;(2) system innovation and specific, highefficiency thermal cycles, which consist of renewable energy-aided coal-fired power generation technologies, a supercritical CO_2 Brayton cycle for coal-fired power plants, large-scale air-cooling coal-fired power plant technologies, and innovative layouts for waste heat utilization and enhanced energy cascade utilization;(3) coal-fired power generation combined with poly-generation technologies, which are represented by integrated gasification combined cycle(IGCC) and integrated gasification fuel cell(IGFC) technologies. Concerning the existing coal-fired power units, which are responsible for peak shaving, possible strategies for enhancing flexibility and operational stability are discussed. Furthermore, future trends for coal-fired power plants coupled with cyber-physical system(CPS) technologies are introduced. The development of advanced, coal-fired power generation technologies demonstrates the progress of science and is suitable for the sustainable development of human society.展开更多
Integrated energy systems(lESs)represent a promising energy supply model within the energy internet.However,multi-energy flow coupling in the optimal configuration of IES results in a series of simplifications in the ...Integrated energy systems(lESs)represent a promising energy supply model within the energy internet.However,multi-energy flow coupling in the optimal configuration of IES results in a series of simplifications in the preliminary planning,affecting the cost,efficiency,and environmental performance of IES.A novel optimal planning method that considers the part-load characteristics and spatio-temporal synergistic effects of IES components is proposed to enable a rational design of the structure and size of IES.An extended energy hub model is introduced based on the“node of energy hub”concept by decomposing the IES into different types of energy equipment.Subsequently,a planning method is applied as a two-level optimization framework-the upper level is used to identify the type and size of the component,while the bottom level is used to optimize the operation strategy based on a typical day analysis method.The planning problem is solved using a two-stage evolutionary algorithm,combing the multiple-mutations adaptive genetic algorithm with an interior point optimization solver,to minimize the lifetime cost of the IES.Finally,the feasibility of the proposed planning method is demonstrated using a case study.The life cycle costs of the IES with and without consideration of the part-load characteristics of the components were$4.26 million and$4.15 million,respectively,in the case study.Moreover,ignoring the variation in component characteristics in the design stage resulted in an additional 11.57%expenditure due to an energy efficiency reduction under the off-design conditions.展开更多
Energy transition towards clean,efficient energy supply has been a common sense of the government and public in China.However,lacking reasonable planning will lead to undisciplined development,resource waste,and exces...Energy transition towards clean,efficient energy supply has been a common sense of the government and public in China.However,lacking reasonable planning will lead to undisciplined development,resource waste,and excessive investment.In this context,this paper investigates potential pathways of Beijing energy transition towards a high-level low-carbon,clean and efficient energy system in 2035 with an extended energysocpe model.Firstly,based on available data,future energy demands are predicted by a newly proposed hybrid forecasting method,which combines the traditional regression model,grey model,and support vector machine model with an entropy-based weighted factor.Secondly,the superstructure-based optimization model is employed to investigate the system configuration and operation strategy of the future Beijing energy system.Finally,the uncertainty impact of electricity price,natural gas price,hydrogen price,and the capital expenditures of electrolyzer and steam methane reforming for hydrogen applications are studied.The forecasting results show that all walks of life will witness a continuously increasing energy demand in multiple sectors of Beijing towards 2035.The planning results suggest that the imported electricity and natural gas will dominate the energy supply of Beijing in 2035 with a contribution of 86%of the energy resources consumption of 384 TWh.Moreover,the energy system presents a high end-use electrification level of 65%and high penetration of efficient technologies,which supply 119 TWh via combined heat and power,26 TWh via heat pump and 95 TWh via district heating network.The energy use of various sectors of energy resources,technologies and end-use are closely related.Hydrogen will have an increased penetration in the private mobility sector,but the locally generated hydrogen is mainly from steam methane reforming technology.展开更多
Venous thromboembolism(VTE)is a complication in children with acute lymphoblastic leukemia(ALL).The Chinese Children’s Cancer Group-ALL-2015 protocol was carried out in China,and epidemiology,clinical characteristics...Venous thromboembolism(VTE)is a complication in children with acute lymphoblastic leukemia(ALL).The Chinese Children’s Cancer Group-ALL-2015 protocol was carried out in China,and epidemiology,clinical characteristics,and risk factors associated with VTE were analyzed.We collected data on VTE in a multiinstitutional clinical study of 7640 patients with ALL diagnosed in 20 hospitals from January 2015 to December 2019.First,VTE occurred in 159(2.08%)patients,including 90(56.6%)during induction therapy and 108(67.92%)in the upper extremities.T-ALL had a 1.74-fold increased risk of VTE(95%CI 1.08–2.8,P=0.022).Septicemia,as an adverse event of ALL treatment,can significantly promote the occurrence of VTE(P<0.001).Catheter-related thrombosis(CRT)accounted for 75.47%(n=120);and,symptomatic VTE,58.49%(n=93),which was more common in patients aged 12–18 years(P=0.023),non-CRT patients(P<0.001),or patients with cerebral thrombosis(P<0.001).Of the patients with VTE treated with anticoagulation therapy(n=147),4.08%(n=6)had bleeding.The VTE recurrence rate was 5.03%(n=8).Patients with VTE treated by non-ultrasoundguided venous cannulation(P=0.02),with residual thrombus(P=0.006),or with short anticoagulation period(P=0.026)had high recurrence rates.Thus,preventing repeated venous puncture and appropriately prolonged anticoagulation time can reduce the risk of VTE recurrence.展开更多
基金supported by the National Nature Science Foundation of China(Grant No.51821004)supported by National Soft Science Projects:"Frontier tracking research on science and technology in the field of energy" program
文摘The development of electrical engineering and electronic, communications, smart power grid, and ultra-high voltage transmission technologies have driven the energy system revolution to the next generation: the energy internet. Progressive penetration of intermittent renewable energy sources into the energy system has led to unprecedented challenges to the currently wide use of coal-fired power generation technologies. Here, the applications and prospects of advanced coal-fired power generation technologies are analyzed. These technologies can be summarized into three categories:(1) large-scale and higher parameters coal-fired power generation technologies, including 620/650/700 oC ultra-supercritical thermal power and double reheat ultra-supercritical coal-fired power generation technologies;(2) system innovation and specific, highefficiency thermal cycles, which consist of renewable energy-aided coal-fired power generation technologies, a supercritical CO_2 Brayton cycle for coal-fired power plants, large-scale air-cooling coal-fired power plant technologies, and innovative layouts for waste heat utilization and enhanced energy cascade utilization;(3) coal-fired power generation combined with poly-generation technologies, which are represented by integrated gasification combined cycle(IGCC) and integrated gasification fuel cell(IGFC) technologies. Concerning the existing coal-fired power units, which are responsible for peak shaving, possible strategies for enhancing flexibility and operational stability are discussed. Furthermore, future trends for coal-fired power plants coupled with cyber-physical system(CPS) technologies are introduced. The development of advanced, coal-fired power generation technologies demonstrates the progress of science and is suitable for the sustainable development of human society.
基金the National Natural Science Foundation of China(Grant No.51821004)supported by the Major Program of the National Natural Science Foundation of China(Grant No.52090062)The author Chengzhou Li also thank the China Scholarship Council(CSC)for the financial support.
文摘Integrated energy systems(lESs)represent a promising energy supply model within the energy internet.However,multi-energy flow coupling in the optimal configuration of IES results in a series of simplifications in the preliminary planning,affecting the cost,efficiency,and environmental performance of IES.A novel optimal planning method that considers the part-load characteristics and spatio-temporal synergistic effects of IES components is proposed to enable a rational design of the structure and size of IES.An extended energy hub model is introduced based on the“node of energy hub”concept by decomposing the IES into different types of energy equipment.Subsequently,a planning method is applied as a two-level optimization framework-the upper level is used to identify the type and size of the component,while the bottom level is used to optimize the operation strategy based on a typical day analysis method.The planning problem is solved using a two-stage evolutionary algorithm,combing the multiple-mutations adaptive genetic algorithm with an interior point optimization solver,to minimize the lifetime cost of the IES.Finally,the feasibility of the proposed planning method is demonstrated using a case study.The life cycle costs of the IES with and without consideration of the part-load characteristics of the components were$4.26 million and$4.15 million,respectively,in the case study.Moreover,ignoring the variation in component characteristics in the design stage resulted in an additional 11.57%expenditure due to an energy efficiency reduction under the off-design conditions.
基金the National Natural Science Foundation of China(No.51821004)the Major Program of the National Natural Science Foundation of China(No.52090062)the Interdisciplinary Innovation Program of North China Electric Power University,and the China Scholarship Council(CSC).
文摘Energy transition towards clean,efficient energy supply has been a common sense of the government and public in China.However,lacking reasonable planning will lead to undisciplined development,resource waste,and excessive investment.In this context,this paper investigates potential pathways of Beijing energy transition towards a high-level low-carbon,clean and efficient energy system in 2035 with an extended energysocpe model.Firstly,based on available data,future energy demands are predicted by a newly proposed hybrid forecasting method,which combines the traditional regression model,grey model,and support vector machine model with an entropy-based weighted factor.Secondly,the superstructure-based optimization model is employed to investigate the system configuration and operation strategy of the future Beijing energy system.Finally,the uncertainty impact of electricity price,natural gas price,hydrogen price,and the capital expenditures of electrolyzer and steam methane reforming for hydrogen applications are studied.The forecasting results show that all walks of life will witness a continuously increasing energy demand in multiple sectors of Beijing towards 2035.The planning results suggest that the imported electricity and natural gas will dominate the energy supply of Beijing in 2035 with a contribution of 86%of the energy resources consumption of 384 TWh.Moreover,the energy system presents a high end-use electrification level of 65%and high penetration of efficient technologies,which supply 119 TWh via combined heat and power,26 TWh via heat pump and 95 TWh via district heating network.The energy use of various sectors of energy resources,technologies and end-use are closely related.Hydrogen will have an increased penetration in the private mobility sector,but the locally generated hydrogen is mainly from steam methane reforming technology.
基金VIVA-China Children's Cancer Foundation and Prof.Pui team.
文摘Venous thromboembolism(VTE)is a complication in children with acute lymphoblastic leukemia(ALL).The Chinese Children’s Cancer Group-ALL-2015 protocol was carried out in China,and epidemiology,clinical characteristics,and risk factors associated with VTE were analyzed.We collected data on VTE in a multiinstitutional clinical study of 7640 patients with ALL diagnosed in 20 hospitals from January 2015 to December 2019.First,VTE occurred in 159(2.08%)patients,including 90(56.6%)during induction therapy and 108(67.92%)in the upper extremities.T-ALL had a 1.74-fold increased risk of VTE(95%CI 1.08–2.8,P=0.022).Septicemia,as an adverse event of ALL treatment,can significantly promote the occurrence of VTE(P<0.001).Catheter-related thrombosis(CRT)accounted for 75.47%(n=120);and,symptomatic VTE,58.49%(n=93),which was more common in patients aged 12–18 years(P=0.023),non-CRT patients(P<0.001),or patients with cerebral thrombosis(P<0.001).Of the patients with VTE treated with anticoagulation therapy(n=147),4.08%(n=6)had bleeding.The VTE recurrence rate was 5.03%(n=8).Patients with VTE treated by non-ultrasoundguided venous cannulation(P=0.02),with residual thrombus(P=0.006),or with short anticoagulation period(P=0.026)had high recurrence rates.Thus,preventing repeated venous puncture and appropriately prolonged anticoagulation time can reduce the risk of VTE recurrence.
