The emergence of Li–Mg hybrid batteries has been receiving attention,owing to their enhanced electrochemical kinetics and reduced overpotential.Nevertheless,the persistent challenge of uneven Mg electrodeposition rem...The emergence of Li–Mg hybrid batteries has been receiving attention,owing to their enhanced electrochemical kinetics and reduced overpotential.Nevertheless,the persistent challenge of uneven Mg electrodeposition remains a significant impediment to their practical integration.Herein,we developed an ingenious approach that centered around epitaxial electrocrystallization and meticulously controlled growth of magnesium crystals on a specialized MgMOF substrate.The chosen MgMOF substrate demonstrated a robust affinity for magnesium and showed minimal lattice misfit with Mg,establishing the crucial prerequisites for successful heteroepitaxial electrocrystallization.Moreover,the incorporation of periodic electric fields and successive nanochannels within the MgMOF structure created a spatially confined environment that considerably promoted uniform magnesium nucleation at the molecular scale.Taking inspiration from the“blockchain”concept prevalent in the realm of big data,we seamlessly integrated a conductive polypyrrole framework,acting as a connecting“chain,”to interlink the“blocks”comprising the MgMOF cavities.This innovative design significantly amplified charge‐transfer efficiency,thereby increasing overall electrochemical kinetics.The resulting architecture(MgMOF@PPy@CC)served as an exceptional host for heteroepitaxial Mg electrodeposition,showcasing remarkable electrostripping/plating kinetics and excellent cycling performance.Surprisingly,a symmetrical cell incorporating the MgMOF@PPy@CC electrode demonstrated impressive stability even under ultrahigh current density conditions(10mAcm–2),maintaining operation for an extended 1200 h,surpassing previously reported benchmarks.Significantly,on coupling the MgMOF@PPy@CC anode with a Mo_(6)S_(8) cathode,the assembled battery showed an extended lifespan of 10,000 cycles at 70 C,with an outstanding capacity retention of 96.23%.This study provides a fresh perspective on the rational design of epitaxial electrocrystallization driven by metal–organic framework(MOF)substrates,paving the way toward the advancement of cuttingedge batteries.展开更多
Effects of three-dimensional(3D)magnetic field perturbations due to feedback control of an unstable n=1(n is toroidal mode number)resistive wall mode(RWM)on the energetic particle(EP)losses are systematically investig...Effects of three-dimensional(3D)magnetic field perturbations due to feedback control of an unstable n=1(n is toroidal mode number)resistive wall mode(RWM)on the energetic particle(EP)losses are systematically investigated for the HL-3 tokamak.The MARS-F(Liu et al 2000 Phys.Plasmas 73681)code,facilitated by the test particle guiding center tracing module REORBIT,is utilized for the study.The RWM is found to generally produce no EP loss for cocurrent particles in HL-3.Assuming the same perturbation level at the sensor location for the close-loop system,feedback produces nearly the same loss of counter-current EPs compared to the open-loop case.Assuming however that the sensor signal is ten times smaller in the close-loop system than the open-loop counter part(reflecting the fact that the RWM is more stable with feedback),the counter-current EP loss is found significantly reduced in the former.Most of EP losses occur only for particles launched close to the plasma edge,while particles launched further away from the plasma boundary experience much less loss.The strike points of lost EPs on the HL-3 limiting surface become more scattered for particles launched closer to the plasma boundary.Taking into account the full gyro-orbit of particles while approaching the limiting surface,REORBIT finds slightly enhanced loss fraction.展开更多
Transport of fast ions is a crucial issue during the operation of ITER.Redistribution of neutral beam injection(NBI)fast ions by the ideal internal magnetohydrodynamic(MHD)instabilities in ITER is studied utilizing th...Transport of fast ions is a crucial issue during the operation of ITER.Redistribution of neutral beam injection(NBI)fast ions by the ideal internal magnetohydrodynamic(MHD)instabilities in ITER is studied utilizing the guiding-center code ORBIT(White R B and Chance M S 1984Phys.Fluids 272455).Effects of the perturbation amplitude A of the internal kink,the perturbation frequency f of the fishbone instability,and the toroidal mode number n of the internal kink are investigated,respectively,in this work.The n=1 internal kink mode can cause NBI fast ions transporting in real space from regions of 0<s≤0.32 to 0.32<s≤0.53,where s labels the normalized plasma radial coordinate.The transport of fast ions is greater as the perturbation amplitude increases.The maximum relative change of the number of fast ions approaches 5%when the perturbation amplitude rises to 500 G.A strong transport is generated between the regions of 0<s≤0.05 and 0.05<s≤0.12 in the presence of the fishbone instability.Higher frequency results in greater transport,and the number of fast ions in 0<s≤0.05 is reduced by 30%at the fishbone frequency of 100 k Hz.Perturbations with higher n will lead to the excursion of fast ion transport regions outward along the radial direction.The loss of fast ions,however,is not affected by the internal MHD perturbation.Strong transport from 0<s≤0.05 to 0.05<s≤0.12 does not influence the plasma heating power of ITER,since the NBI fast ions are still located in the plasma core.On the other hand,the influence of fast ion transport from 0<s≤0.32 to 0.32<s≤0.53 needs further study.展开更多
The critical gradient mode(CGM) is employed to predict the energetic particle(EP) transport induced by the Alfven eigenmode(AE).To improve the model,the normalized critical density gradient is set as an inverse propor...The critical gradient mode(CGM) is employed to predict the energetic particle(EP) transport induced by the Alfven eigenmode(AE).To improve the model,the normalized critical density gradient is set as an inverse proportional function of energetic particle density;consequently,the threshold evolves during EP transport.Moreover,in order to consider the EP orbit loss mechanism in CGM,ORBIT code is employed to calculate the EP loss cone in phase space.With these improvements,the AE enhances EPs radial transport,pushing the particles into the loss cone.The combination of the two mechanisms raises the lost fraction to 6.6%,which is higher than the linear superposition of the two mechanisms.However,the loss is still far lower than that observed in current experiments.Avoiding significant overlap between the AE unstable region and the loss cone is a key factor in minimizing EP loss.展开更多
This case study discusses a 51-year-old woman with a complex cardiovascular condition,cor triatriatum dexter,complicated by sick sinus syndrome.The patient presented with a history of bradycardia,dizziness,and amauros...This case study discusses a 51-year-old woman with a complex cardiovascular condition,cor triatriatum dexter,complicated by sick sinus syndrome.The patient presented with a history of bradycardia,dizziness,and amaurosis,and was admitted to the emergency department due to numbness in her right limb.Diagnostic examinations,including computed tomography(CT)and cardiac color-ultrasound screening,revealed cor triatriatum dexter along with an enlarged left atrium and ventricle.Additional findings included the absence of the inferior vena cava and polysplenic syndrome.Based on these results,double-chamber pacemaker surgery was recommended,supported by cardiac and thoracic-abdominal CT angiography and three-dimensional vascular reconstruction.This case underscores the importance of comprehensive examinations in identifying associated cardiovascular abnormalities.展开更多
Low alloying Mg-2 Gd-0.5(Cu/Ni)alloys for sealing tools in the oil and gas industry were prepared.The differences in the effects of minor Cu and Ni additions on microstructures and properties of the Mg-2 Gd alloy were...Low alloying Mg-2 Gd-0.5(Cu/Ni)alloys for sealing tools in the oil and gas industry were prepared.The differences in the effects of minor Cu and Ni additions on microstructures and properties of the Mg-2 Gd alloy were compared.The results showed that adding Ni was more effective than adding Cu in refining grain sizes,strengthening the basal fiber texture,and promoting the formation of LPSO phases,resulting in higher strength.The tensile yield strength/elongation of the Mg-2 Gd-0.5 Cu alloy,Mg-2 Gd-0.25 Cu-0.25 Ni alloy,and Mg-2 Gd-0.5 Ni alloy was 146 MPa/23.7%,175 MPa/23.1%,and 248 MPa/18.2%,respectively.The decreased elongation was attributed to the basal fiber texture and the presence of coarse LPSO phases.In terms of the corrosion rate in 3.5 wt.%NaCl solution,it rose from 112 mm y^(-1)for the Mg-2 Gd-0.5 Cu alloy to 269 mm y^(-1)for the Mg-2 Gd-0.25 Cu-0.25 Ni alloy and 490 mm y^(-1)for the Mg-2 Gd-0.5 Ni alloy,indicating that the addition of Ni instead of Cu showed a more significant promoting effect on the degradability of Mg alloys,which was related to more refined grains,the stronger basal fiber texture,and a larger amount of LPSO phases.展开更多
China has become the third largest source of outward direct investment (ODI). This paper studies how institutions in the host countries affect the location choices of China's ODI. Based on a deal-level sample from ...China has become the third largest source of outward direct investment (ODI). This paper studies how institutions in the host countries affect the location choices of China's ODI. Based on a deal-level sample from 2002-2011, this paper empirically tests how political institutions, political stability, government effectiveness, regulatory quality, rule of law and contrd of corruption in the host countries affect the location choices of China's ODI. On top of these institutional factors, we study the effects of tax evasion and natural resources in host countries, and their interactions with institutional factors. We find that political institutions in the host countries are not major concerns of the ODI, while government effectiveness, regulatory quality, and control of corruption have significant effects on the locations of ODI. In addition, China's ODI tends to avoid countries with strict legal systems. Tax evasion and resources are also major motives of China's ODI. General institutional quality and tax evasion are substitutes in China's ODI location decisions.展开更多
基金National Natural Science Foundation of China,Grant/Award Number:31770608Postgraduate Research&Practice Innovation Program of Jiangsu Province,Grant/Award Number:KYCX22_1081Jiangsu Specially‐appointed Professorship Program,Grant/Award Number:Sujiaoshi[2016]20。
文摘The emergence of Li–Mg hybrid batteries has been receiving attention,owing to their enhanced electrochemical kinetics and reduced overpotential.Nevertheless,the persistent challenge of uneven Mg electrodeposition remains a significant impediment to their practical integration.Herein,we developed an ingenious approach that centered around epitaxial electrocrystallization and meticulously controlled growth of magnesium crystals on a specialized MgMOF substrate.The chosen MgMOF substrate demonstrated a robust affinity for magnesium and showed minimal lattice misfit with Mg,establishing the crucial prerequisites for successful heteroepitaxial electrocrystallization.Moreover,the incorporation of periodic electric fields and successive nanochannels within the MgMOF structure created a spatially confined environment that considerably promoted uniform magnesium nucleation at the molecular scale.Taking inspiration from the“blockchain”concept prevalent in the realm of big data,we seamlessly integrated a conductive polypyrrole framework,acting as a connecting“chain,”to interlink the“blocks”comprising the MgMOF cavities.This innovative design significantly amplified charge‐transfer efficiency,thereby increasing overall electrochemical kinetics.The resulting architecture(MgMOF@PPy@CC)served as an exceptional host for heteroepitaxial Mg electrodeposition,showcasing remarkable electrostripping/plating kinetics and excellent cycling performance.Surprisingly,a symmetrical cell incorporating the MgMOF@PPy@CC electrode demonstrated impressive stability even under ultrahigh current density conditions(10mAcm–2),maintaining operation for an extended 1200 h,surpassing previously reported benchmarks.Significantly,on coupling the MgMOF@PPy@CC anode with a Mo_(6)S_(8) cathode,the assembled battery showed an extended lifespan of 10,000 cycles at 70 C,with an outstanding capacity retention of 96.23%.This study provides a fresh perspective on the rational design of epitaxial electrocrystallization driven by metal–organic framework(MOF)substrates,paving the way toward the advancement of cuttingedge batteries.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2022YFE03090000 and 2022YFE03060002)National Natural Science Foundation of China(No.12375214)+3 种基金China National Nuclear Corporation Fundamental Research Program(No.CNNC-JCYJ-202236)Innovation Program of Southwestern Institute of Physics(No.202301XWCX006-04)supported by Youth Science and Technology Innovation Team of Sichuan Province(No.2022JDTD0003)US DoE Office of Science(Nos.DE-FG02-95ER54309 and DE-FC02-04ER54698)。
文摘Effects of three-dimensional(3D)magnetic field perturbations due to feedback control of an unstable n=1(n is toroidal mode number)resistive wall mode(RWM)on the energetic particle(EP)losses are systematically investigated for the HL-3 tokamak.The MARS-F(Liu et al 2000 Phys.Plasmas 73681)code,facilitated by the test particle guiding center tracing module REORBIT,is utilized for the study.The RWM is found to generally produce no EP loss for cocurrent particles in HL-3.Assuming the same perturbation level at the sensor location for the close-loop system,feedback produces nearly the same loss of counter-current EPs compared to the open-loop case.Assuming however that the sensor signal is ten times smaller in the close-loop system than the open-loop counter part(reflecting the fact that the RWM is more stable with feedback),the counter-current EP loss is found significantly reduced in the former.Most of EP losses occur only for particles launched close to the plasma edge,while particles launched further away from the plasma boundary experience much less loss.The strike points of lost EPs on the HL-3 limiting surface become more scattered for particles launched closer to the plasma boundary.Taking into account the full gyro-orbit of particles while approaching the limiting surface,REORBIT finds slightly enhanced loss fraction.
基金supported by the National Key Research and Development Program of China(Nos.2022YFE03060002,2019YFE03090100)by the Innovation Program of Southwestern Institute of Physics(No.202001XWCXRC001)partly supported by the Youth Science and Technology Innovation Team of Sichuan Province(No.2022JDTD0003)。
文摘Transport of fast ions is a crucial issue during the operation of ITER.Redistribution of neutral beam injection(NBI)fast ions by the ideal internal magnetohydrodynamic(MHD)instabilities in ITER is studied utilizing the guiding-center code ORBIT(White R B and Chance M S 1984Phys.Fluids 272455).Effects of the perturbation amplitude A of the internal kink,the perturbation frequency f of the fishbone instability,and the toroidal mode number n of the internal kink are investigated,respectively,in this work.The n=1 internal kink mode can cause NBI fast ions transporting in real space from regions of 0<s≤0.32 to 0.32<s≤0.53,where s labels the normalized plasma radial coordinate.The transport of fast ions is greater as the perturbation amplitude increases.The maximum relative change of the number of fast ions approaches 5%when the perturbation amplitude rises to 500 G.A strong transport is generated between the regions of 0<s≤0.05 and 0.05<s≤0.12 in the presence of the fishbone instability.Higher frequency results in greater transport,and the number of fast ions in 0<s≤0.05 is reduced by 30%at the fishbone frequency of 100 k Hz.Perturbations with higher n will lead to the excursion of fast ion transport regions outward along the radial direction.The loss of fast ions,however,is not affected by the internal MHD perturbation.Strong transport from 0<s≤0.05 to 0.05<s≤0.12 does not influence the plasma heating power of ITER,since the NBI fast ions are still located in the plasma core.On the other hand,the influence of fast ion transport from 0<s≤0.32 to 0.32<s≤0.53 needs further study.
基金the National Key R&D Program of China(Grant No.2019TFE03020000)the National Natural Science Foundation of China(Grant Nos.11875021,12005054,and 12005055)the Sichuan Science and Technology Program(Grant No.2020jqqn0070)。
文摘The critical gradient mode(CGM) is employed to predict the energetic particle(EP) transport induced by the Alfven eigenmode(AE).To improve the model,the normalized critical density gradient is set as an inverse proportional function of energetic particle density;consequently,the threshold evolves during EP transport.Moreover,in order to consider the EP orbit loss mechanism in CGM,ORBIT code is employed to calculate the EP loss cone in phase space.With these improvements,the AE enhances EPs radial transport,pushing the particles into the loss cone.The combination of the two mechanisms raises the lost fraction to 6.6%,which is higher than the linear superposition of the two mechanisms.However,the loss is still far lower than that observed in current experiments.Avoiding significant overlap between the AE unstable region and the loss cone is a key factor in minimizing EP loss.
基金Hunan Province Natural Science Foundation(Grant No.2020JJ8061)Hunan Province Science and Technology Innovation Program Project(Project No.2020SK50921)。
文摘This case study discusses a 51-year-old woman with a complex cardiovascular condition,cor triatriatum dexter,complicated by sick sinus syndrome.The patient presented with a history of bradycardia,dizziness,and amaurosis,and was admitted to the emergency department due to numbness in her right limb.Diagnostic examinations,including computed tomography(CT)and cardiac color-ultrasound screening,revealed cor triatriatum dexter along with an enlarged left atrium and ventricle.Additional findings included the absence of the inferior vena cava and polysplenic syndrome.Based on these results,double-chamber pacemaker surgery was recommended,supported by cardiac and thoracic-abdominal CT angiography and three-dimensional vascular reconstruction.This case underscores the importance of comprehensive examinations in identifying associated cardiovascular abnormalities.
基金financially supported by the National Key Research and Development Program of China(No.2019YFC1520303)the Scientific and Technological Research Program of Chongqing Municipal Education Commission(No.KJQN202001527)the Natural Science Foundation of Zhejiang Province(No.LQ18E010003)。
文摘Low alloying Mg-2 Gd-0.5(Cu/Ni)alloys for sealing tools in the oil and gas industry were prepared.The differences in the effects of minor Cu and Ni additions on microstructures and properties of the Mg-2 Gd alloy were compared.The results showed that adding Ni was more effective than adding Cu in refining grain sizes,strengthening the basal fiber texture,and promoting the formation of LPSO phases,resulting in higher strength.The tensile yield strength/elongation of the Mg-2 Gd-0.5 Cu alloy,Mg-2 Gd-0.25 Cu-0.25 Ni alloy,and Mg-2 Gd-0.5 Ni alloy was 146 MPa/23.7%,175 MPa/23.1%,and 248 MPa/18.2%,respectively.The decreased elongation was attributed to the basal fiber texture and the presence of coarse LPSO phases.In terms of the corrosion rate in 3.5 wt.%NaCl solution,it rose from 112 mm y^(-1)for the Mg-2 Gd-0.5 Cu alloy to 269 mm y^(-1)for the Mg-2 Gd-0.25 Cu-0.25 Ni alloy and 490 mm y^(-1)for the Mg-2 Gd-0.5 Ni alloy,indicating that the addition of Ni instead of Cu showed a more significant promoting effect on the degradability of Mg alloys,which was related to more refined grains,the stronger basal fiber texture,and a larger amount of LPSO phases.
文摘China has become the third largest source of outward direct investment (ODI). This paper studies how institutions in the host countries affect the location choices of China's ODI. Based on a deal-level sample from 2002-2011, this paper empirically tests how political institutions, political stability, government effectiveness, regulatory quality, rule of law and contrd of corruption in the host countries affect the location choices of China's ODI. On top of these institutional factors, we study the effects of tax evasion and natural resources in host countries, and their interactions with institutional factors. We find that political institutions in the host countries are not major concerns of the ODI, while government effectiveness, regulatory quality, and control of corruption have significant effects on the locations of ODI. In addition, China's ODI tends to avoid countries with strict legal systems. Tax evasion and resources are also major motives of China's ODI. General institutional quality and tax evasion are substitutes in China's ODI location decisions.