The world is facing the third important global power shift.The United States,EU, Japan,Russia,China,and the newly emerging power group are becoming the six big forces in the international center stage,while the former...The world is facing the third important global power shift.The United States,EU, Japan,Russia,China,and the newly emerging power group are becoming the six big forces in the international center stage,while the former three forces and the latter three belong to two groups,waning and waxing respectively.The major shift in the global balance of power is bound to give rise to the transitional multi-polar configuration,which implies a shifting of leadership over the configuration,China and U.S.outweighing other forces,global issues looming large,homogeneity blending with heterogeneity,and a shifting center of world powers.The transitional multi-polar configuration is all about change,upon which China is one of the decisive forces.展开更多
Under the pressure of environmental issues,decarbonization of the entire energy system has emerged as a prevalent strategy worldwide.The evolution of China’s power system will increasingly emphasize the integration o...Under the pressure of environmental issues,decarbonization of the entire energy system has emerged as a prevalent strategy worldwide.The evolution of China’s power system will increasingly emphasize the integration of variable renewable energy(VRE).However,the rapid growth of VRE will pose substantial challenges to the power system,highlighting the importance of power system planning.This letter introduces Grid Optimal Planning Tool(GOPT),a planning tool,and presents the key findings of our research utilizing GOPT to analyze the transition pathway of China’s power system towards dual carbon goals.Furthermore,the letter offers insights into key technologies essential for driving the future transition of China’s power system.展开更多
The analysis refers to the interwar years in Europe.We distinguish four types of coalitions here:(a)Coalitions with other democratic parties,led by a predominant party and most common in multi-party democratic states....The analysis refers to the interwar years in Europe.We distinguish four types of coalitions here:(a)Coalitions with other democratic parties,led by a predominant party and most common in multi-party democratic states.(b)Bringing in ideological opponents on the parts of overarching highly credible national figures such as King George V did in Britain in 1931 in calling upon the charismatic Labour Party leader MacDonald to form a coalition with the still dominant but ailing Conservative Party.(c)The outbidding of more radical political parties by former center parties towards the right or left.One such outcome comes about when this is having a temporary effect only,until the next election is won within the family of democratic parties.Yet,when outbidding is trump the electorate easily might go for the hardest outbidding contender not to be taken over by even greater extremist parties.This process for the analysis of political terrorism and its intention to instigate fear amongst the“neutral”population explains to a large extent why considerable portions of the population are going to side with the most extreme challengers.This is for two reasons,one is pure fear to be out-mastered,the other one is rational choice just to avoid this.(d)The other outcome as to outbidding occurs when the democratic national consensus formation that is still underlying all these processes in normal times is wiped out in times of crises.Democratic national consensus is being lost vis-à-vis a new anti-democratic national consensus formation.Several other theoretical arguments and historical experiences are touched upon.展开更多
The use of an electrical network as close as possible to its limits can lead to its instability in the event of a high amplitude disturbance. The damping of system oscillations can be achieved by conventional means of...The use of an electrical network as close as possible to its limits can lead to its instability in the event of a high amplitude disturbance. The damping of system oscillations can be achieved by conventional means of voltage and speed regulation but also by FACTS (Flexible AC Transmission Systems) devices, which are increasingly used in power networks. In this work, optimal control coordination between a hybrid power flow controller and a three-level inverter was used to improve the transient stability of a transmission line. The UPFC is a combination of a serial compensator (SSSC) and a parallel compensator (STATCOM) both connected to a DC-LINK DC bus. The SSSC acts as a voltage source for the network and injects a voltage that can be adjusted in phase and amplitude in addition to the network voltage;the STATCOM acts as a current source. The approach used is tested in the Matlab Simulink environment on a single machine network. Optimal controller tuning gives a better transient stability improvement by reducing the transport angle oscillations from 248.17% to 9.85%.展开更多
The effect of transition metal ions(M^(2+)=Mn^(2+),Ni^(2+),Co^(2+),Cu^(2+)) on the chemical synthesis of polyaniline(PANI) used as a platinum-free counter electrode(CE) in dye-sensitized solar cells(DSSCs) was investi...The effect of transition metal ions(M^(2+)=Mn^(2+),Ni^(2+),Co^(2+),Cu^(2+)) on the chemical synthesis of polyaniline(PANI) used as a platinum-free counter electrode(CE) in dye-sensitized solar cells(DSSCs) was investigated.PANI was synthesized by co-polymerization of aniline in the presence of different transition metal ions by using potassium dichromate in acidic medium. It was found that the ion doping of PANI showed a certain catalytic activity for the regeneration of traditional iodide/triiodide(I^-/I_3^-) redox couples. The power conversion efficiency(η) of PANI CEs doped with Mn^(2+),Ni^(2+),Co^(2+) (4.41%, 2.36% and 2.10%, respectively) were higher than 1.94%, the value measured for PANI CE without doping. Doping with Cu^(2+)decreased the power conversion efficiency of PANI CE(PANI-Cu^(2+) η = 1.41%). The electrical properties of the PANI, PANI-Ni^(2+), PANI-Co^(2+),PANI-Mn^(2+) and PANI-Cu^(2+) were studied by cyclic voltammetry(CV), impedance(EIS), and Tafel polarization curve. The experimental results confirmed that PANI was affected by the doping of different transition metal ions(M^(2+)=Mn^(2+),Ni^(2+),Co^(2+),Cu^(2+)). These results indicate a potential application of ion doped PANI as counter electrode in cost-effective DSSCs.展开更多
An attempt has been made to explore whether the power relation can be obtained from theoretical considerations. The classical laminar and turbulent boundary layer concepts have been employed to determine appropriate v...An attempt has been made to explore whether the power relation can be obtained from theoretical considerations. The classical laminar and turbulent boundary layer concepts have been employed to determine appropriate values of the scaling lengths associated with vortex shedding and shear layer frequencies to predict the power law relationship with Reynolds number. The predicted results are in good agreement with experimental results. The findings will provide a greater insight into the overall phenomenon involved.展开更多
This paper goes beyond Sino-Nordic Arctic science diplomacy and looks at Sino-Nordic Arctic triple-helix knowledge- based collaborations among academia, business, civil society （the inclusion of which moves beyond th...This paper goes beyond Sino-Nordic Arctic science diplomacy and looks at Sino-Nordic Arctic triple-helix knowledge- based collaborations among academia, business, civil society （the inclusion of which moves beyond the original triple-helix concept）, and government. In light of the potential of science diplomacy for building Sino-Arctic trust under systemic international conditions of power transition and globalization, this is the natural next step toward exploring triple-helix collaborations. Knowledge-based collaborations between academia, business, civil society, and government also open up avenues for innovation and entrepreneurship by both Arctic societies and Chinese society in attempts to address major challenges to sustainable development in these societies. This paper discusses possible triple-helix knowledge-based collaborations with China by each of the five Nordic countries, and highlights the innovation and entrepreneurial talents of summer school students at the University of International Relations in Beijing in developing projects as part of a course entitled ＂The Global Arctic＂.展开更多
Pressure fluctuations signals of a lab-scale fiuidized bed （15 cm inner diameter and 2 m height） at different superficial gas velocities were measured. Recurrence plot （RP） and recurrence rate （RR）, and the simp...Pressure fluctuations signals of a lab-scale fiuidized bed （15 cm inner diameter and 2 m height） at different superficial gas velocities were measured. Recurrence plot （RP） and recurrence rate （RR）, and the simplest variable of recurrence quantification analysis （RQA） were used to analyze the pressure signals. Different patterns observed in RP reflect different dynamic behavior of the system under study. It was also found that the variance of RR （a2R） Could reveal the peak dominant frequencies （PDF） of different dynamic systems： completely periodic, completely stochastic, Lorenz system, and fluidized bed. The results were compared with power spectral density. Additionally, the diagram of σ^2RR provides a new technique for prediction of transition velocity from bubbling to turbulent fluidization regime.展开更多
文摘The world is facing the third important global power shift.The United States,EU, Japan,Russia,China,and the newly emerging power group are becoming the six big forces in the international center stage,while the former three forces and the latter three belong to two groups,waning and waxing respectively.The major shift in the global balance of power is bound to give rise to the transitional multi-polar configuration,which implies a shifting of leadership over the configuration,China and U.S.outweighing other forces,global issues looming large,homogeneity blending with heterogeneity,and a shifting center of world powers.The transitional multi-polar configuration is all about change,upon which China is one of the decisive forces.
基金supported by the National Natural Science Foundation of China(No.52130702,No.52177093)。
文摘Under the pressure of environmental issues,decarbonization of the entire energy system has emerged as a prevalent strategy worldwide.The evolution of China’s power system will increasingly emphasize the integration of variable renewable energy(VRE).However,the rapid growth of VRE will pose substantial challenges to the power system,highlighting the importance of power system planning.This letter introduces Grid Optimal Planning Tool(GOPT),a planning tool,and presents the key findings of our research utilizing GOPT to analyze the transition pathway of China’s power system towards dual carbon goals.Furthermore,the letter offers insights into key technologies essential for driving the future transition of China’s power system.
文摘The analysis refers to the interwar years in Europe.We distinguish four types of coalitions here:(a)Coalitions with other democratic parties,led by a predominant party and most common in multi-party democratic states.(b)Bringing in ideological opponents on the parts of overarching highly credible national figures such as King George V did in Britain in 1931 in calling upon the charismatic Labour Party leader MacDonald to form a coalition with the still dominant but ailing Conservative Party.(c)The outbidding of more radical political parties by former center parties towards the right or left.One such outcome comes about when this is having a temporary effect only,until the next election is won within the family of democratic parties.Yet,when outbidding is trump the electorate easily might go for the hardest outbidding contender not to be taken over by even greater extremist parties.This process for the analysis of political terrorism and its intention to instigate fear amongst the“neutral”population explains to a large extent why considerable portions of the population are going to side with the most extreme challengers.This is for two reasons,one is pure fear to be out-mastered,the other one is rational choice just to avoid this.(d)The other outcome as to outbidding occurs when the democratic national consensus formation that is still underlying all these processes in normal times is wiped out in times of crises.Democratic national consensus is being lost vis-à-vis a new anti-democratic national consensus formation.Several other theoretical arguments and historical experiences are touched upon.
文摘The use of an electrical network as close as possible to its limits can lead to its instability in the event of a high amplitude disturbance. The damping of system oscillations can be achieved by conventional means of voltage and speed regulation but also by FACTS (Flexible AC Transmission Systems) devices, which are increasingly used in power networks. In this work, optimal control coordination between a hybrid power flow controller and a three-level inverter was used to improve the transient stability of a transmission line. The UPFC is a combination of a serial compensator (SSSC) and a parallel compensator (STATCOM) both connected to a DC-LINK DC bus. The SSSC acts as a voltage source for the network and injects a voltage that can be adjusted in phase and amplitude in addition to the network voltage;the STATCOM acts as a current source. The approach used is tested in the Matlab Simulink environment on a single machine network. Optimal controller tuning gives a better transient stability improvement by reducing the transport angle oscillations from 248.17% to 9.85%.
基金Supported by the National Natural Science Foundation of China(21473048,21303039)the Natural Science Foundation of Hebei Province(B2016205161,B2015205163)the 2015 Hebei Province Undergraduate Training Programs for Innovation and Entrepreneurship
文摘The effect of transition metal ions(M^(2+)=Mn^(2+),Ni^(2+),Co^(2+),Cu^(2+)) on the chemical synthesis of polyaniline(PANI) used as a platinum-free counter electrode(CE) in dye-sensitized solar cells(DSSCs) was investigated.PANI was synthesized by co-polymerization of aniline in the presence of different transition metal ions by using potassium dichromate in acidic medium. It was found that the ion doping of PANI showed a certain catalytic activity for the regeneration of traditional iodide/triiodide(I^-/I_3^-) redox couples. The power conversion efficiency(η) of PANI CEs doped with Mn^(2+),Ni^(2+),Co^(2+) (4.41%, 2.36% and 2.10%, respectively) were higher than 1.94%, the value measured for PANI CE without doping. Doping with Cu^(2+)decreased the power conversion efficiency of PANI CE(PANI-Cu^(2+) η = 1.41%). The electrical properties of the PANI, PANI-Ni^(2+), PANI-Co^(2+),PANI-Mn^(2+) and PANI-Cu^(2+) were studied by cyclic voltammetry(CV), impedance(EIS), and Tafel polarization curve. The experimental results confirmed that PANI was affected by the doping of different transition metal ions(M^(2+)=Mn^(2+),Ni^(2+),Co^(2+),Cu^(2+)). These results indicate a potential application of ion doped PANI as counter electrode in cost-effective DSSCs.
文摘An attempt has been made to explore whether the power relation can be obtained from theoretical considerations. The classical laminar and turbulent boundary layer concepts have been employed to determine appropriate values of the scaling lengths associated with vortex shedding and shear layer frequencies to predict the power law relationship with Reynolds number. The predicted results are in good agreement with experimental results. The findings will provide a greater insight into the overall phenomenon involved.
基金China Nordic Arctic Research Center(Polar Research Institute of China)for providing me with a visiting fellowship from 1 March to 28 April,2016funding from the Department of Sociology,Political Science and Community Planning,and the HSL-utdanningsfond(Faculty of Humanities,Social Sciences and Education Teaching Fund),University of Tromso-The Arctic University of Norway,to attend the China-Nordic Arctic Cooperation Symposium in Rovaniemi from 6 to 9 June,2016
文摘This paper goes beyond Sino-Nordic Arctic science diplomacy and looks at Sino-Nordic Arctic triple-helix knowledge- based collaborations among academia, business, civil society （the inclusion of which moves beyond the original triple-helix concept）, and government. In light of the potential of science diplomacy for building Sino-Arctic trust under systemic international conditions of power transition and globalization, this is the natural next step toward exploring triple-helix collaborations. Knowledge-based collaborations between academia, business, civil society, and government also open up avenues for innovation and entrepreneurship by both Arctic societies and Chinese society in attempts to address major challenges to sustainable development in these societies. This paper discusses possible triple-helix knowledge-based collaborations with China by each of the five Nordic countries, and highlights the innovation and entrepreneurial talents of summer school students at the University of International Relations in Beijing in developing projects as part of a course entitled ＂The Global Arctic＂.
基金Supports from the Iran National Science Foundation(INSF) in lran(No.91001766)
文摘Pressure fluctuations signals of a lab-scale fiuidized bed （15 cm inner diameter and 2 m height） at different superficial gas velocities were measured. Recurrence plot （RP） and recurrence rate （RR）, and the simplest variable of recurrence quantification analysis （RQA） were used to analyze the pressure signals. Different patterns observed in RP reflect different dynamic behavior of the system under study. It was also found that the variance of RR （a2R） Could reveal the peak dominant frequencies （PDF） of different dynamic systems： completely periodic, completely stochastic, Lorenz system, and fluidized bed. The results were compared with power spectral density. Additionally, the diagram of σ^2RR provides a new technique for prediction of transition velocity from bubbling to turbulent fluidization regime.
