Perovskite materials have emerged as promising candidates for various optoelectronic applications owing to their remarkable optoelectronic properties and easy solution processing.Metal halide perovskites,as direct-ban...Perovskite materials have emerged as promising candidates for various optoelectronic applications owing to their remarkable optoelectronic properties and easy solution processing.Metal halide perovskites,as direct-bandgap semiconductors,show an excellent class of optical gain media,which makes them applicable to the development of low-threshold or even thresholdless lasers.This mini review explores recent advances in perovskite-based laser technology,which have led to chiral single-mode microlasers,low-threshold,external-cavity-free lasing devices at room temperature,and other innovative device architectures.Including self-assembled CsPbBr3 microwires that enable edge lasing.Realized continuous-wave(CW)pumped lasing by perovskite material pushes the research of electrically driven perovskite lasers.The capacity to regulate charge transport in halide perovskites further enhances their applicability in optoelectronic systems.The ongoing integration of perovskite materials with advanced photonic structures holds excellent potential for future innovations in laser technology and photovoltaics.We also highlight the transformative potential of perovskite materials in advancing the next generation of efficient and integrated optoelectronic devices.展开更多
The experimental studies of the wave breaking effects on freak wave generation are presented within a finite-depth random wave train in a laboratory wave tank. The main attention is paid to the abnormal index, AI = Hm...The experimental studies of the wave breaking effects on freak wave generation are presented within a finite-depth random wave train in a laboratory wave tank. The main attention is paid to the abnormal index, AI = Hmas/Hs, being used to characterize the freak waves, and the changes of the coefficient due to wave breaking. The results show that the occurrence probability of freak wave events in non-breaking waves is much larger than that in bleaking waves and such occurrence in deep water is larger than that in shallow water.展开更多
A constrained interpolation profile CIP-based numerical tank is developed to simulate violent free surface flows.The numerical simulation is performed by the CIP-based Cartesian grid method,which is described in the p...A constrained interpolation profile CIP-based numerical tank is developed to simulate violent free surface flows.The numerical simulation is performed by the CIP-based Cartesian grid method,which is described in the present paper.The tangent of hyperbola for interface capturing（THINC） scheme is applied for capturing complex free surfaces.The new model is capable of simulating a flow with violently varied free surface.A series of computations are conducted to assess the developed algorithm and its versatility.These tests include the collapse of water column with and without an obstacle,sloshing in a fixed tank,the generation of regular waves in a tank,the generation of extreme waves in a tank.Excellent agreements are obtained when numerical results are compared with available analytical,experimental,and other numerical results.展开更多
A numerical model was established for simulating wave impact on a horizontal deck by an improved incompressible smoothed particle hydrodynamics (ISPH). As a grid-less particle method, the ISPH method has been widely u...A numerical model was established for simulating wave impact on a horizontal deck by an improved incompressible smoothed particle hydrodynamics (ISPH). As a grid-less particle method, the ISPH method has been widely used in the free-surface hydrodynamic flows with good accuracy. The improvement includes the employment of a corrective function for enhancement of angular momentum conservation in a particle-based calculation and a new estimation method to predict the pressure on the horizontal deck. The simulation results show a good agreement with the experiment. The present numerical model can be used to study wave impact load on the horizontal deck.展开更多
Two different kinds of hot compressions,namely normal-compression and can-compression,were performed on the Mg–11 Gd–4 Y–2 Zn–0.5 Zr alloy,featured with long period stacking ordered(LPSO)phase.The kinking behavior...Two different kinds of hot compressions,namely normal-compression and can-compression,were performed on the Mg–11 Gd–4 Y–2 Zn–0.5 Zr alloy,featured with long period stacking ordered(LPSO)phase.The kinking behavior of LPSO phase and microstructure evolution was investigated to clarify the effect of levels of imposed hydrostatic pressure.The results suggest that the LPSO phases including both the intragranular 14 H-LPSO phase and intergranular 18 R-LPSO phase suffer severe kinking behavior under higher hydrostatic pressure induced by can-compression,which is firstly characterized with more kinking times and smaller relative kinking width.The main reason for such enhanced LPSO kinking during cancompression may be mainly ascribed to the higher dislocation density under a higher level of hydrostatic pressure.Meanwhile,a competitive relationship between the kink behaviors of intergranular 18 R-LPSO phase and intragranular 14 H-LPSO phase was observed.That is,the intergranular 18 R-LPSO phase only kinks obviously on the condition that the surrounded intragranular 14 H-LPSO phase scarcely kinks.In contrast to the distinctive kinking of LPSO phase,the dynamic recrystallization(DRX)mechanism shows less dependence on the hydrostatic pressure.Resultantly,similar DRX fractions and crystallographic texture were attained for two compression processes owing to the similar operation of deformation mode.展开更多
Modified electrically assisted(EA) rapid heating of Al–Si-coated hot stamping steel is suggested, and the intermetallic evolution in the coating during heating is experimentally investigated. In the modified EA rapid...Modified electrically assisted(EA) rapid heating of Al–Si-coated hot stamping steel is suggested, and the intermetallic evolution in the coating during heating is experimentally investigated. In the modified EA rapid heating, a continuous electric current for a suitable duration is applied to a specimen to heat it to a temperature slightly below the melting temperature of the coating. The temperature of the specimen is then kept constant for a specified dwell time. The result of the microstructural analysis shows that the modified EA rapid heating could effectively increase the thickness of the intermetallic layer between the coating and steel substrate much faster than conventional furnace heating and induction heating. The effectiveness of EA rapid heating may be due to the athermal effect of the electric current on the mobility of atoms, in addition to the well-known resistance heating effect. EA rapid heating also provides a technical advantage in that partial austenization can be easily achieved by properly placing the electrodes, as demonstrated in the present study.展开更多
This paper describes the numerical study of nonstratified airflow over a real complex terrain. Attention is focused on the mechanism of a local strong wind induced by a topographic effect. In order to clarify the mech...This paper describes the numerical study of nonstratified airflow over a real complex terrain. Attention is focused on the mechanism of a local strong wind induced by a topographic effect. In order to clarify the mechanism of the occurrence of strong winds accompanied by the effects of terrain, the use of a numerical simulation is very effective, in which conditions can be set without the influence of ground roughness and temperature distribution. As a result, airflow converged to a small basin of mountain terrain in the upper stream, and local strong wind was generated leeward along the slope of the mountain terrain. Furthermore, the influence of the reproduction accuracy of geographical features, that is, horizontal grid resolution, was examined. Consequently, to reproduce the above-mentioned local strong wind, it was shown that horizontal grid resolution from 50 m to about 100 m was necessary.展开更多
The present study compared the prediction accuracy of the three CFD software packages for simulating airflow around a three-dimensional, isolated hill with a steep slope: 1) WindSim (turbulence model: RNG k-ε RANS), ...The present study compared the prediction accuracy of the three CFD software packages for simulating airflow around a three-dimensional, isolated hill with a steep slope: 1) WindSim (turbulence model: RNG k-ε RANS), 2) Meteodyn WT (turbulence model: k-L RANS), which are the leading commercially available CFD software packages in the wind power industry and 3) RIAM-COMPACT (turbulence model: standard Smagorinsky LES), which has been developed by the lead author of the present paper. Distinct differences in the airflow patterns were identified in the vicinity of the isolated hill (especially downstream of the hill) between the RANS results and the LES results. No reverse flow region (vortex region) characterized by negative wind velocities was identified downstream of the isolated hill in the result from the simulation with WindSim (RNG k-ε RANS) and Meteodyn WT (k-L RANS). In the case of the simulation with RIAM-COMPACT natural terrain version (standard Smagorinsky LES), a reverse flow region (vortex region) characterized by negative wind velocities clearly forms. Next, an example of wind risk (terrain-induced turbulence) diagnostics was presented for a large-scale wind farm in China. The vertical profiles of the streamwise (x) wind velocity do not follow the so-called power law wind profile;a large velocity deficit can be seen between the hub center and the lower end of the swept area in the case of the LES calculation (RIAM-COMPACT).展开更多
The increasing demand for hydrogen energy to address environmental issues and achieve carbon neutrality has elevated interest in green hydrogen production,which does not rely on fossil fuels.Among various hydrogen pro...The increasing demand for hydrogen energy to address environmental issues and achieve carbon neutrality has elevated interest in green hydrogen production,which does not rely on fossil fuels.Among various hydrogen production technologies,anion exchange membrane water electrolyzer(AEMWE)has emerged as a next-generation technology known for its high hydrogen production efficiency and its ability to use non-metal catalysts.However,this technology faces significant challenges,particularly in terms of the membrane durability and low ionic conductivity.To address these challenges,research efforts have focused on developing membranes with a new backbone structure and anion exchange groups to enhance durability and ionic conductivity.Notably,the super-acid-catalyzed condensation(SACC)synthesis method stands out due to its user convenience,the ability to create high molecular weight(MW)polymers,and the use of oxygen-tolerant organic catalysts.Although the synthesis of anion exchange membranes(AEMs)using the SACC method began in 2015,and despite growing interest in this synthesis approach,there remains a scarcity of review papers focusing on AEMs synthesized using the SACC method.The review covers the basics of SACC synthesis,presents various polymers synthesized using this method,and summarizes the development of these polymers,particularly their building blocks including aryl,ketone,and anion exchange groups.We systematically describe the effects of changes in the molecular structure of each polymer component,conducted by various research groups,on the mechanical properties,conductivity,and operational stability of the membrane.This review will provide insights into the development of AEMs with superior performance and operational stability suitable for water electrolysis applications.展开更多
Biodegradable metals as electrodes, interconnectors, and device conductors are essential components in the emergence of transient electronics, either for passive implants or active electronic devices, especially in th...Biodegradable metals as electrodes, interconnectors, and device conductors are essential components in the emergence of transient electronics, either for passive implants or active electronic devices, especially in the fields of biomedical electronics. Magnesium and its alloys are strong candidates for biodegradable and implantable conducting materials because of their high conductivity and biocompatibility, in addition to their well-understood dissolution behavior. One critical drawback of Mg and its alloys is their considerably high dissolution rates originating from their low anodic potential, which disturbs the compatibility to biomedical applications. Herein, we introduce a single-phase thin film of a Mg-Zn binary alloy formed by sputtering, which enhances the corrosion resistance of the device electrode, and verify its applicability in biodegradable electronics. The formation of a homogeneous solid solution of single-phase Mg-3Zn was confirmed through X-ray diffraction and transmission electron microscopy. In addition, the dissolution behavior and chemistry was also investigated in various biological fluids by considering the effect of different ion species. Micro-tensile tests showed that the Mg-3Zn alloy electrode exhibited an enhanced yield strain and elongation in relation to a pure Mg electrode. Cell viability test revealed the high biocompatibility rate of the Mg-3Zn binary alloy thin film. Finally, the fabrication of a wireless heater demonstrated the integrability of biodegradable electrodes and highlighted the ability to prolong the lifecycle of thermotherapy-relevant electronics by enhancing the dissolution resistance of the Mg alloy.展开更多
Most organic electrode materials(OEMs)for rechargeable batteries employ n-type redox centers,whose redox potentials are intrinsically limited<3.0 V versus Li^(+)/Li.However,p-type materials possessing high redox po...Most organic electrode materials(OEMs)for rechargeable batteries employ n-type redox centers,whose redox potentials are intrinsically limited<3.0 V versus Li^(+)/Li.However,p-type materials possessing high redox potentials experience low specific capacities because they are capable of only a single redox reaction within the stable electrochemical window of typical electrolytes.Herein,we report 5,11-diethyl-5,11-dihydroindolo[3,2-b]carbazole(DEICZ)as a novel p-type OEM,exhibiting stable plateaus at high discharge potentials of 3.44 and 4.09 V versus Li^(+)/Li.Notably,the second redox potential of DEICZ is within the stable electrochemical window.The mechanism of the double redox reaction is investigated using both theoretical calculations and experimental measurements,including density functional theory calculations,ex situ electron spin resonance,and X-ray photoelectron spectroscopy.Finally,hybridization with single-walled carbon nanotubes(SWCNT)improves the cycle stability and rate performance of DEICZ owing to theπ-πinteractions between the SWCNT and co-planar molecular structure of DEICZ,preventing the dissolution of active materials into the electrolyte.The DEICZ/SWCNT composite electrode maintains 70.4%of its initial specific capacity at 1-C rate and also exhibits high-rate capability,even performing well at 100-C rate.Furthermore,we demonstrate its potential for flexible batteries after applying 1000 bending stresses to the composite electrode.展开更多
QUEST has a divertor configuration with a high and a negative n-index, and the problem of plasma vertical position instability control in QUEST is still under extensive study for achieving high efficiency plasma. The ...QUEST has a divertor configuration with a high and a negative n-index, and the problem of plasma vertical position instability control in QUEST is still under extensive study for achieving high efficiency plasma. The instability we considered is that the toroidal plasma moves either up or down in the vacuum chamber until it meets the vessel wall and is extinguished. The actively controlled coils （HCU and HCL） outside the vacuum vessel are serially connected in feedback with a measurement of the plasma vertical position to provide stabilizing control. In this work, a robust controller is employed by using the loop synthesis method, and provides robust stability over a wide range of n-index. Moreover, the gain of the robust controller is lower than that of a typical proportional derivative （PD） controller in the operational frequency range; it indicates that the robust controller needs less power consumption than the PD controller does.展开更多
The influence of wave breaking on wave statistics for finite-depth random wave trains is investigated experimentally. This paper is to investigate the influence of wave breaking and water depth on the wave statistics ...The influence of wave breaking on wave statistics for finite-depth random wave trains is investigated experimentally. This paper is to investigate the influence of wave breaking and water depth on the wave statistics for random waves on water of finite depth. Greater attention is paid to changes in wave statistics due to wave breaking in random wave trains. The results show skewness of surface elevations is independent of wave breaking and kurtosis is suppressed by wave breaking. Finally, the exceedance probabilities for wave heights are also investigated.展开更多
Three-dimensional ( 3-D) directional wave focusing is one of the mechanisms that contribute to the generation of freak waves. To simulate and analyze this phenomenon,a 3-D wave focusing model is proposed based on the ...Three-dimensional ( 3-D) directional wave focusing is one of the mechanisms that contribute to the generation of freak waves. To simulate and analyze this phenomenon,a 3-D wave focusing model is proposed based on the enhanced high-order spectral method,which solves the fully nonlinear potential flow equations with a free surface within periodic unbounded 3-D domains. The numerical model is validated against a fifth-order Stokes solution for regular waves. Laboratory-scale freak waves are observed with wave components having equal amplitudes. Investigations of the appearance and propagation of freak-wave events in a 3-D open wavefield defined by a directional wave spectrum are then realized.展开更多
A one-channel microwave reflectometer is used to measure the electron densityprofile in a low-density plasma experiment (n_e < 0.27 x 10^(19) m^(-3)) sustained by 2.45 GHzlower hybrid current drive (LHCD) on TRIAM-...A one-channel microwave reflectometer is used to measure the electron densityprofile in a low-density plasma experiment (n_e < 0.27 x 10^(19) m^(-3)) sustained by 2.45 GHzlower hybrid current drive (LHCD) on TRIAM-1M. In order to remove the effect of phase runawayphenomena, a step-like frequency-sweeping way is used and a special phase analysis technique isintroduced. The density profile is reconstructed in TRIAM-1M with the swept frequency ranged from 6GHz to 15 GHz. The corresponding cutoff density is from (0.045 ～ 0.28) x 10^(19) m^(-3) in theordinary polarization mode. The results are in good agreement with the measurements from amulti-channel 2 mm-wavelength interferometer.展开更多
文摘Perovskite materials have emerged as promising candidates for various optoelectronic applications owing to their remarkable optoelectronic properties and easy solution processing.Metal halide perovskites,as direct-bandgap semiconductors,show an excellent class of optical gain media,which makes them applicable to the development of low-threshold or even thresholdless lasers.This mini review explores recent advances in perovskite-based laser technology,which have led to chiral single-mode microlasers,low-threshold,external-cavity-free lasing devices at room temperature,and other innovative device architectures.Including self-assembled CsPbBr3 microwires that enable edge lasing.Realized continuous-wave(CW)pumped lasing by perovskite material pushes the research of electrically driven perovskite lasers.The capacity to regulate charge transport in halide perovskites further enhances their applicability in optoelectronic systems.The ongoing integration of perovskite materials with advanced photonic structures holds excellent potential for future innovations in laser technology and photovoltaics.We also highlight the transformative potential of perovskite materials in advancing the next generation of efficient and integrated optoelectronic devices.
基金supported by the National Natural Science Foundation of China (Grant No.50779004)
文摘The experimental studies of the wave breaking effects on freak wave generation are presented within a finite-depth random wave train in a laboratory wave tank. The main attention is paid to the abnormal index, AI = Hmas/Hs, being used to characterize the freak waves, and the changes of the coefficient due to wave breaking. The results show that the occurrence probability of freak wave events in non-breaking waves is much larger than that in bleaking waves and such occurrence in deep water is larger than that in shallow water.
基金supported by the Fundamental Research Funds for the Central Universities
文摘A constrained interpolation profile CIP-based numerical tank is developed to simulate violent free surface flows.The numerical simulation is performed by the CIP-based Cartesian grid method,which is described in the present paper.The tangent of hyperbola for interface capturing（THINC） scheme is applied for capturing complex free surfaces.The new model is capable of simulating a flow with violently varied free surface.A series of computations are conducted to assess the developed algorithm and its versatility.These tests include the collapse of water column with and without an obstacle,sloshing in a fixed tank,the generation of regular waves in a tank,the generation of extreme waves in a tank.Excellent agreements are obtained when numerical results are compared with available analytical,experimental,and other numerical results.
基金the National High Technology Research and Development Program of China (863 Program,Grant No.2007AA11Z130)
文摘A numerical model was established for simulating wave impact on a horizontal deck by an improved incompressible smoothed particle hydrodynamics (ISPH). As a grid-less particle method, the ISPH method has been widely used in the free-surface hydrodynamic flows with good accuracy. The improvement includes the employment of a corrective function for enhancement of angular momentum conservation in a particle-based calculation and a new estimation method to predict the pressure on the horizontal deck. The simulation results show a good agreement with the experiment. The present numerical model can be used to study wave impact load on the horizontal deck.
基金financially supported by the National Natural Science Foundation of China(Contract No.51305188)。
文摘Two different kinds of hot compressions,namely normal-compression and can-compression,were performed on the Mg–11 Gd–4 Y–2 Zn–0.5 Zr alloy,featured with long period stacking ordered(LPSO)phase.The kinking behavior of LPSO phase and microstructure evolution was investigated to clarify the effect of levels of imposed hydrostatic pressure.The results suggest that the LPSO phases including both the intragranular 14 H-LPSO phase and intergranular 18 R-LPSO phase suffer severe kinking behavior under higher hydrostatic pressure induced by can-compression,which is firstly characterized with more kinking times and smaller relative kinking width.The main reason for such enhanced LPSO kinking during cancompression may be mainly ascribed to the higher dislocation density under a higher level of hydrostatic pressure.Meanwhile,a competitive relationship between the kink behaviors of intergranular 18 R-LPSO phase and intragranular 14 H-LPSO phase was observed.That is,the intergranular 18 R-LPSO phase only kinks obviously on the condition that the surrounded intragranular 14 H-LPSO phase scarcely kinks.In contrast to the distinctive kinking of LPSO phase,the dynamic recrystallization(DRX)mechanism shows less dependence on the hydrostatic pressure.Resultantly,similar DRX fractions and crystallographic texture were attained for two compression processes owing to the similar operation of deformation mode.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Ministry of Science,ICT and Future Planning(MSIP)(NRF-2015R1A5A1037627)the Technology Innovation Program(Industrial Strategic Technology Development Program,10044807.Development of technologies for vehicle body part made from UHSS and Al5000 by electrically assisted manufacturing)funded by the Ministry of Trade,Industry and Energy(MOTIE,Korea)
文摘Modified electrically assisted(EA) rapid heating of Al–Si-coated hot stamping steel is suggested, and the intermetallic evolution in the coating during heating is experimentally investigated. In the modified EA rapid heating, a continuous electric current for a suitable duration is applied to a specimen to heat it to a temperature slightly below the melting temperature of the coating. The temperature of the specimen is then kept constant for a specified dwell time. The result of the microstructural analysis shows that the modified EA rapid heating could effectively increase the thickness of the intermetallic layer between the coating and steel substrate much faster than conventional furnace heating and induction heating. The effectiveness of EA rapid heating may be due to the athermal effect of the electric current on the mobility of atoms, in addition to the well-known resistance heating effect. EA rapid heating also provides a technical advantage in that partial austenization can be easily achieved by properly placing the electrodes, as demonstrated in the present study.
文摘This paper describes the numerical study of nonstratified airflow over a real complex terrain. Attention is focused on the mechanism of a local strong wind induced by a topographic effect. In order to clarify the mechanism of the occurrence of strong winds accompanied by the effects of terrain, the use of a numerical simulation is very effective, in which conditions can be set without the influence of ground roughness and temperature distribution. As a result, airflow converged to a small basin of mountain terrain in the upper stream, and local strong wind was generated leeward along the slope of the mountain terrain. Furthermore, the influence of the reproduction accuracy of geographical features, that is, horizontal grid resolution, was examined. Consequently, to reproduce the above-mentioned local strong wind, it was shown that horizontal grid resolution from 50 m to about 100 m was necessary.
文摘The present study compared the prediction accuracy of the three CFD software packages for simulating airflow around a three-dimensional, isolated hill with a steep slope: 1) WindSim (turbulence model: RNG k-ε RANS), 2) Meteodyn WT (turbulence model: k-L RANS), which are the leading commercially available CFD software packages in the wind power industry and 3) RIAM-COMPACT (turbulence model: standard Smagorinsky LES), which has been developed by the lead author of the present paper. Distinct differences in the airflow patterns were identified in the vicinity of the isolated hill (especially downstream of the hill) between the RANS results and the LES results. No reverse flow region (vortex region) characterized by negative wind velocities was identified downstream of the isolated hill in the result from the simulation with WindSim (RNG k-ε RANS) and Meteodyn WT (k-L RANS). In the case of the simulation with RIAM-COMPACT natural terrain version (standard Smagorinsky LES), a reverse flow region (vortex region) characterized by negative wind velocities clearly forms. Next, an example of wind risk (terrain-induced turbulence) diagnostics was presented for a large-scale wind farm in China. The vertical profiles of the streamwise (x) wind velocity do not follow the so-called power law wind profile;a large velocity deficit can be seen between the hub center and the lower end of the swept area in the case of the LES calculation (RIAM-COMPACT).
基金supported by the KRISS(Korea Research Institute of Standards and Science)MPI Lab.program。
文摘The increasing demand for hydrogen energy to address environmental issues and achieve carbon neutrality has elevated interest in green hydrogen production,which does not rely on fossil fuels.Among various hydrogen production technologies,anion exchange membrane water electrolyzer(AEMWE)has emerged as a next-generation technology known for its high hydrogen production efficiency and its ability to use non-metal catalysts.However,this technology faces significant challenges,particularly in terms of the membrane durability and low ionic conductivity.To address these challenges,research efforts have focused on developing membranes with a new backbone structure and anion exchange groups to enhance durability and ionic conductivity.Notably,the super-acid-catalyzed condensation(SACC)synthesis method stands out due to its user convenience,the ability to create high molecular weight(MW)polymers,and the use of oxygen-tolerant organic catalysts.Although the synthesis of anion exchange membranes(AEMs)using the SACC method began in 2015,and despite growing interest in this synthesis approach,there remains a scarcity of review papers focusing on AEMs synthesized using the SACC method.The review covers the basics of SACC synthesis,presents various polymers synthesized using this method,and summarizes the development of these polymers,particularly their building blocks including aryl,ketone,and anion exchange groups.We systematically describe the effects of changes in the molecular structure of each polymer component,conducted by various research groups,on the mechanical properties,conductivity,and operational stability of the membrane.This review will provide insights into the development of AEMs with superior performance and operational stability suitable for water electrolysis applications.
基金supported by the Renewable Energy Technology Development (Develop technology to enhance reliability and durability for parts of hydrogen storage tank system) (2022303004020B) grant funded by the Korea Energy Technology Evaluation Planning (KETEP)the Ministry of Science and ICT (Development Project for Emerging Research Instruments Technology),(Project Number: (2022)ERIC)06_1Commercialization Promotion Agency for R&D Outcomes (COMPA)。
文摘Biodegradable metals as electrodes, interconnectors, and device conductors are essential components in the emergence of transient electronics, either for passive implants or active electronic devices, especially in the fields of biomedical electronics. Magnesium and its alloys are strong candidates for biodegradable and implantable conducting materials because of their high conductivity and biocompatibility, in addition to their well-understood dissolution behavior. One critical drawback of Mg and its alloys is their considerably high dissolution rates originating from their low anodic potential, which disturbs the compatibility to biomedical applications. Herein, we introduce a single-phase thin film of a Mg-Zn binary alloy formed by sputtering, which enhances the corrosion resistance of the device electrode, and verify its applicability in biodegradable electronics. The formation of a homogeneous solid solution of single-phase Mg-3Zn was confirmed through X-ray diffraction and transmission electron microscopy. In addition, the dissolution behavior and chemistry was also investigated in various biological fluids by considering the effect of different ion species. Micro-tensile tests showed that the Mg-3Zn alloy electrode exhibited an enhanced yield strain and elongation in relation to a pure Mg electrode. Cell viability test revealed the high biocompatibility rate of the Mg-3Zn binary alloy thin film. Finally, the fabrication of a wireless heater demonstrated the integrability of biodegradable electrodes and highlighted the ability to prolong the lifecycle of thermotherapy-relevant electronics by enhancing the dissolution resistance of the Mg alloy.
基金supported by the National Research Foundation(NRF)of Korea grant funded by the Korean government(MSIT)(2023R1A2C2002605)Korea Institute of Science and Technology(KIST,Korea)Institutional Program(2Z06903 and 2E32634)supported by the Basic Science Research Program through the NRF funded by the Ministry of Science(NRF-2021R1A2C4002030)
文摘Most organic electrode materials(OEMs)for rechargeable batteries employ n-type redox centers,whose redox potentials are intrinsically limited<3.0 V versus Li^(+)/Li.However,p-type materials possessing high redox potentials experience low specific capacities because they are capable of only a single redox reaction within the stable electrochemical window of typical electrolytes.Herein,we report 5,11-diethyl-5,11-dihydroindolo[3,2-b]carbazole(DEICZ)as a novel p-type OEM,exhibiting stable plateaus at high discharge potentials of 3.44 and 4.09 V versus Li^(+)/Li.Notably,the second redox potential of DEICZ is within the stable electrochemical window.The mechanism of the double redox reaction is investigated using both theoretical calculations and experimental measurements,including density functional theory calculations,ex situ electron spin resonance,and X-ray photoelectron spectroscopy.Finally,hybridization with single-walled carbon nanotubes(SWCNT)improves the cycle stability and rate performance of DEICZ owing to theπ-πinteractions between the SWCNT and co-planar molecular structure of DEICZ,preventing the dissolution of active materials into the electrolyte.The DEICZ/SWCNT composite electrode maintains 70.4%of its initial specific capacity at 1-C rate and also exhibits high-rate capability,even performing well at 100-C rate.Furthermore,we demonstrate its potential for flexible batteries after applying 1000 bending stresses to the composite electrode.
文摘QUEST has a divertor configuration with a high and a negative n-index, and the problem of plasma vertical position instability control in QUEST is still under extensive study for achieving high efficiency plasma. The instability we considered is that the toroidal plasma moves either up or down in the vacuum chamber until it meets the vessel wall and is extinguished. The actively controlled coils （HCU and HCL） outside the vacuum vessel are serially connected in feedback with a measurement of the plasma vertical position to provide stabilizing control. In this work, a robust controller is employed by using the loop synthesis method, and provides robust stability over a wide range of n-index. Moreover, the gain of the robust controller is lower than that of a typical proportional derivative （PD） controller in the operational frequency range; it indicates that the robust controller needs less power consumption than the PD controller does.
基金Supported by the National Natural Science Foundation of China under Grant No.50579007the National High Technology Research and Development Program of China (863 Program) under Grant No. 2007AA11Z130
文摘The influence of wave breaking on wave statistics for finite-depth random wave trains is investigated experimentally. This paper is to investigate the influence of wave breaking and water depth on the wave statistics for random waves on water of finite depth. Greater attention is paid to changes in wave statistics due to wave breaking in random wave trains. The results show skewness of surface elevations is independent of wave breaking and kurtosis is suppressed by wave breaking. Finally, the exceedance probabilities for wave heights are also investigated.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 50779004)
文摘Three-dimensional ( 3-D) directional wave focusing is one of the mechanisms that contribute to the generation of freak waves. To simulate and analyze this phenomenon,a 3-D wave focusing model is proposed based on the enhanced high-order spectral method,which solves the fully nonlinear potential flow equations with a free surface within periodic unbounded 3-D domains. The numerical model is validated against a fifth-order Stokes solution for regular waves. Laboratory-scale freak waves are observed with wave components having equal amplitudes. Investigations of the appearance and propagation of freak-wave events in a 3-D open wavefield defined by a directional wave spectrum are then realized.
文摘A one-channel microwave reflectometer is used to measure the electron densityprofile in a low-density plasma experiment (n_e < 0.27 x 10^(19) m^(-3)) sustained by 2.45 GHzlower hybrid current drive (LHCD) on TRIAM-1M. In order to remove the effect of phase runawayphenomena, a step-like frequency-sweeping way is used and a special phase analysis technique isintroduced. The density profile is reconstructed in TRIAM-1M with the swept frequency ranged from 6GHz to 15 GHz. The corresponding cutoff density is from (0.045 ～ 0.28) x 10^(19) m^(-3) in theordinary polarization mode. The results are in good agreement with the measurements from amulti-channel 2 mm-wavelength interferometer.
