To the Editor:Salam et al.found that more than half(54.2%)of Indonesian parents surveyed were willing to pay for a dengue vaccination[1].Using the Health Belief Model,the study identified four constructs that signific...To the Editor:Salam et al.found that more than half(54.2%)of Indonesian parents surveyed were willing to pay for a dengue vaccination[1].Using the Health Belief Model,the study identified four constructs that significantly influenced willingness to pay,including Perceived Susceptibility,Perceived Severity,Perceived Benefits,and Cues to Action[1].Interestingly,Perceived Barriers,including cost and potential side effects,did not show a significant effect[1].展开更多
This work concerns defense guidance problems for 3-player target–defender–attacker engagement scenarios,in which the defender is launched to capture the incoming attacker in advance of the target being hit;a line-of...This work concerns defense guidance problems for 3-player target–defender–attacker engagement scenarios,in which the defender is launched to capture the incoming attacker in advance of the target being hit;a line-of-sight(LOS)triangle-based prescribed-time guidance is derived as an interception strategy for the defender.Integrating both the attacker–target and defender–attacker perspectives into the relative engagement model,the 3-player nonlinear engagement model is deduced considering the second-order lag dynamics of the actuator.Next,to reduce the defender and attacker overload ratio,the LOS triangle-guidance concept is presented to keep the defender on the LOS frame between the attacker and the target,in which the lateral overloads of the defender and attacker cancel each other out.In addition,in order to achieve perfect capture of the attacker in advance,the prescribed-time control can preallocate convergence time such that the defender can be guided and kept at the LOS frame between the attacker and the target in the preset time.What is even more unique is that the proposed guidance law design ignores the maneuvering of the attacker;i.e.,the overload of the attacker is unknown,which is treated as a disturbance and estimated by the improved adaptive law.Numerical simulations are executed to validate performance and superiority,which has potential application value.展开更多
The trivalent dysprosium-doped yellow phosphor is an important component for realizing single-matrix white light.However,concentration quenching and thermal quenching greatly limit its application.White light phosphor...The trivalent dysprosium-doped yellow phosphor is an important component for realizing single-matrix white light.However,concentration quenching and thermal quenching greatly limit its application.White light phosphors,Li_(3)Ba_(2)Gd_(3)(WO_(4))_(8):Dy^(3+),Tm^(3+),with a stratified scheelite structure were prepared via a high-temperature solid-reaction.Calculated using the Kubelka–Munk model,the band gap of the host is 3.71 eV,which is suitable for near-ultraviolet white LEDs.展开更多
The dynamic behavior of a cavitation bubble near an asymmetric hydrofoil is investigated experimentally through high-speed photography and theoretically using a Kelvin impulse model.The typical deformations arising du...The dynamic behavior of a cavitation bubble near an asymmetric hydrofoil is investigated experimentally through high-speed photography and theoretically using a Kelvin impulse model.The typical deformations arising during bubble collapse near the hydrofoil are analyzed qualitatively.The effects of the bubble position and the hydrofoil’s eccentricity angle are analyzed quantitatively.The spatial distribution of the Kelvin impulse near the hydrofoil are explored.Different morphological evolutions of a bubble near an asymmetric hydrofoil are revealed,with B-shaped,heart-shaped,and arc-shaped collapses.The velocity of the bubble interface close to the hydrofoil is significantly affected by the bubble-hydrofoil distance and the hydrofoil’s eccentricity angle,increasing as both the distance and the eccentricity angle grow.It is found that the Kelvin impulse sensitivity varies at different positions with respect to the asymmetric hydrofoil,being higher at the head and tail,and lower in the middle.展开更多
This study integrates first-principles calculations,computational chemistry,system simulations,experiments,and machine learning to identify redox perovskite oxides for solar thermochemical hydrogen production.Using tw...This study integrates first-principles calculations,computational chemistry,system simulations,experiments,and machine learning to identify redox perovskite oxides for solar thermochemical hydrogen production.Using two random forest regressions and one classification model,the approach predicts materials’stability and the enthalpy of oxygen vacancy formation(Δh_(o)),a critical property for selecting materials for thermochemical hydrogen production.B-site composition significantly influencesΔho predictions.The methodology led to the discovery of Ba_(0.875)Ca_(0.125)Zr_(0.875)Mn_(0.125)O_(3)(BCZM),which reduces at temperatures up to 250°C lower than CeO_(2)and is expected to outperform other perovskites in water splitting.However,CeO_(2)remains the benchmark for solar thermochemical hydrogen production.The combined use of machine learning and DFT calculations refined 4ho predictions and provided insights into experimental results.This framework not only enhances database creation for material screening but also establishes a novel approach for perovskite discovery for hydrogen production applications.展开更多
The integration of numerous distributed energy resources and power electronic devices introduces a wide spectrum of frequency disturbances,which significantly challenge the stability of modern power systems.Therefore,...The integration of numerous distributed energy resources and power electronic devices introduces a wide spectrum of frequency disturbances,which significantly challenge the stability of modern power systems.Therefore,there is an urgent need to enhance the current monitoring level of modern power systems.This paper proposes a novel busbar current inversion scheme based on an elliptical magnetic sensor array.By establishing a simulation model,the effect of structural parameters of the elliptical array on its current measurement accuracy was analysed.The anti-interference capability of the elliptical array in complex environments such as busbar displacement and crosstalk was studied,and principles for designing array parameters under different current sensor standards were established.Experiments conducted on the proposed current sensing scheme demon-strated that the designed current array has a range of 0-150 A,with a current mea-surement error below 0.1% without external interference and not exceeding 1%during busbar displacement.Under conditions of crosstalk,the measurement accuracy achieved was class 0.5.The sensor array possesses high measurement accuracy,robust anti-interference capability,low power consumption,compact size and a noncontact nature.It exhibits significant potential for extensive application in novel business scenarios within the power system.展开更多
The Longchuan River basin lies within the China Sichuan-Yunnan rhomboid block.The NS-trending Yuanmou-Lvzhi River Fault(YLF),NW-trending Chuxiong-Nanhua Fault(CNF)and Shiyang-Huoshaotun Fault(HSF)are found within the ...The Longchuan River basin lies within the China Sichuan-Yunnan rhomboid block.The NS-trending Yuanmou-Lvzhi River Fault(YLF),NW-trending Chuxiong-Nanhua Fault(CNF)and Shiyang-Huoshaotun Fault(HSF)are found within the basin.The nature of the faults is complex,and the tectonic activity distribution characteristics require further clarification.By extraction from a digital elevation model,the measured longitudinal profile and the geomorphic indices of the Longchuan River,basin showed a stream-length gradient index(SL)of 49–650,hypsometric integral(HI)of 0.27–0.58,drainage basin asymmetry factor(AF)of 3.29–27.47,basin shape index(BS)of 0.87–2.75,valley floor width-to-height ratio(VF)of 0.06–5.40,and evaluation of relative tectonic activity(Iat)of 1.6–2.6.Results showed that river morphology and geomorphological indices in the Longchuan River basin were influenced by tectonic activity,bedrock lithology,climatic conditions,and development time,with tectonic activity playing a dominant role.The relative tectonic activity of the Longchuan River basin was zoned,with a gradual increase in relative tectonic activity from the south to the north.That the slip fault zone primarily controls the tectonic deformation of the Longchuan River basin in central Yunnan and the dynamics of the central Yunnan massif are consistent with the“rigid block lateral extrusion”1model.展开更多
文摘To the Editor:Salam et al.found that more than half(54.2%)of Indonesian parents surveyed were willing to pay for a dengue vaccination[1].Using the Health Belief Model,the study identified four constructs that significantly influenced willingness to pay,including Perceived Susceptibility,Perceived Severity,Perceived Benefits,and Cues to Action[1].Interestingly,Perceived Barriers,including cost and potential side effects,did not show a significant effect[1].
基金cosupported by the National Natural Science Foundation of China(Nos.12072090,12322202,12172013,12302056).
文摘This work concerns defense guidance problems for 3-player target–defender–attacker engagement scenarios,in which the defender is launched to capture the incoming attacker in advance of the target being hit;a line-of-sight(LOS)triangle-based prescribed-time guidance is derived as an interception strategy for the defender.Integrating both the attacker–target and defender–attacker perspectives into the relative engagement model,the 3-player nonlinear engagement model is deduced considering the second-order lag dynamics of the actuator.Next,to reduce the defender and attacker overload ratio,the LOS triangle-guidance concept is presented to keep the defender on the LOS frame between the attacker and the target,in which the lateral overloads of the defender and attacker cancel each other out.In addition,in order to achieve perfect capture of the attacker in advance,the prescribed-time control can preallocate convergence time such that the defender can be guided and kept at the LOS frame between the attacker and the target in the preset time.What is even more unique is that the proposed guidance law design ignores the maneuvering of the attacker;i.e.,the overload of the attacker is unknown,which is treated as a disturbance and estimated by the improved adaptive law.Numerical simulations are executed to validate performance and superiority,which has potential application value.
基金financially supported by the National Natural Science Foundation of China(No.51902354 and 22061020)the Science and Technology Program of Jiangxi Province(No.20192BBEL50017and 20202ACBL203002)+2 种基金the Characteristic Innovation Projects in Colleges and Universities in Guangdong Province(No.2021KTSCX128)theGDAS’Project of Science and Technology Development(No.2022GDASZH-2022010104 and 2022GDASZH-2022030604-04)the Special Found Project of Institute of Rare Metals,Guangdong Academy of Sciences(No.XYS2020-02).
文摘The trivalent dysprosium-doped yellow phosphor is an important component for realizing single-matrix white light.However,concentration quenching and thermal quenching greatly limit its application.White light phosphors,Li_(3)Ba_(2)Gd_(3)(WO_(4))_(8):Dy^(3+),Tm^(3+),with a stratified scheelite structure were prepared via a high-temperature solid-reaction.Calculated using the Kubelka–Munk model,the band gap of the host is 3.71 eV,which is suitable for near-ultraviolet white LEDs.
基金supported by the National Natural Science Foundation of China(Project No.51976056).
文摘The dynamic behavior of a cavitation bubble near an asymmetric hydrofoil is investigated experimentally through high-speed photography and theoretically using a Kelvin impulse model.The typical deformations arising during bubble collapse near the hydrofoil are analyzed qualitatively.The effects of the bubble position and the hydrofoil’s eccentricity angle are analyzed quantitatively.The spatial distribution of the Kelvin impulse near the hydrofoil are explored.Different morphological evolutions of a bubble near an asymmetric hydrofoil are revealed,with B-shaped,heart-shaped,and arc-shaped collapses.The velocity of the bubble interface close to the hydrofoil is significantly affected by the bubble-hydrofoil distance and the hydrofoil’s eccentricity angle,increasing as both the distance and the eccentricity angle grow.It is found that the Kelvin impulse sensitivity varies at different positions with respect to the asymmetric hydrofoil,being higher at the head and tail,and lower in the middle.
基金funding from ARENA as part of ARENA’s Research and Development Program–Renewable Hydrogen for ExportAC and RP gratefully acknowledge the financial support by Programa Atracción de Talento Fellowship of“Comunidad de Madrid”(2022-T1/AMB-23875)+2 种基金J.C.,A.B.,and A.C.thank Comunidad de Madrid”for the financial support to ACES4NET0-CM project(TEC-2024/ECO-116),through the R&D activities programme“Tecnologías 2024”.SD acknowledges support from the University of Newcastle Priority Research Centre for Frontier Energy Technologies and UtilizationM.V.G.P.thanks for the Grant PID2021-128915NB-I00 funded by MCIN/AEI/10.13039/501100011033 and by ERDF,UE.A.B.and L.M.gratefully acknowledge the financial support by Programa de Atracción de Talento Fellowship of“Comunidad de Madrid”(2020-T1/AMB-19884)A.B.also acknowledge the funding from Consolidacion Investigadora Fellowship(CNS2023-144887).We thank B.Baldassarri for helpful discussions.Computer time provided by the RES(Red Española de Supercomputación)resources at MareNostrum(BSC,Barcelona)node is acknowledged.
文摘This study integrates first-principles calculations,computational chemistry,system simulations,experiments,and machine learning to identify redox perovskite oxides for solar thermochemical hydrogen production.Using two random forest regressions and one classification model,the approach predicts materials’stability and the enthalpy of oxygen vacancy formation(Δh_(o)),a critical property for selecting materials for thermochemical hydrogen production.B-site composition significantly influencesΔho predictions.The methodology led to the discovery of Ba_(0.875)Ca_(0.125)Zr_(0.875)Mn_(0.125)O_(3)(BCZM),which reduces at temperatures up to 250°C lower than CeO_(2)and is expected to outperform other perovskites in water splitting.However,CeO_(2)remains the benchmark for solar thermochemical hydrogen production.The combined use of machine learning and DFT calculations refined 4ho predictions and provided insights into experimental results.This framework not only enhances database creation for material screening but also establishes a novel approach for perovskite discovery for hydrogen production applications.
基金National Key Research and Development Program of China,Grant/Award Number:2022YFB2402900Science and Technology Project of State Grid,Grant/Award Number:52060023001T。
文摘The integration of numerous distributed energy resources and power electronic devices introduces a wide spectrum of frequency disturbances,which significantly challenge the stability of modern power systems.Therefore,there is an urgent need to enhance the current monitoring level of modern power systems.This paper proposes a novel busbar current inversion scheme based on an elliptical magnetic sensor array.By establishing a simulation model,the effect of structural parameters of the elliptical array on its current measurement accuracy was analysed.The anti-interference capability of the elliptical array in complex environments such as busbar displacement and crosstalk was studied,and principles for designing array parameters under different current sensor standards were established.Experiments conducted on the proposed current sensing scheme demon-strated that the designed current array has a range of 0-150 A,with a current mea-surement error below 0.1% without external interference and not exceeding 1%during busbar displacement.Under conditions of crosstalk,the measurement accuracy achieved was class 0.5.The sensor array possesses high measurement accuracy,robust anti-interference capability,low power consumption,compact size and a noncontact nature.It exhibits significant potential for extensive application in novel business scenarios within the power system.
基金central Yunnan Province(1:50,000)Chuxiong City,central Yunnan Province(Grant/Award Numbers:DD20220987)the National Natural Science Foundation of China(Grant/Award Numbers:41972118).
文摘The Longchuan River basin lies within the China Sichuan-Yunnan rhomboid block.The NS-trending Yuanmou-Lvzhi River Fault(YLF),NW-trending Chuxiong-Nanhua Fault(CNF)and Shiyang-Huoshaotun Fault(HSF)are found within the basin.The nature of the faults is complex,and the tectonic activity distribution characteristics require further clarification.By extraction from a digital elevation model,the measured longitudinal profile and the geomorphic indices of the Longchuan River,basin showed a stream-length gradient index(SL)of 49–650,hypsometric integral(HI)of 0.27–0.58,drainage basin asymmetry factor(AF)of 3.29–27.47,basin shape index(BS)of 0.87–2.75,valley floor width-to-height ratio(VF)of 0.06–5.40,and evaluation of relative tectonic activity(Iat)of 1.6–2.6.Results showed that river morphology and geomorphological indices in the Longchuan River basin were influenced by tectonic activity,bedrock lithology,climatic conditions,and development time,with tectonic activity playing a dominant role.The relative tectonic activity of the Longchuan River basin was zoned,with a gradual increase in relative tectonic activity from the south to the north.That the slip fault zone primarily controls the tectonic deformation of the Longchuan River basin in central Yunnan and the dynamics of the central Yunnan massif are consistent with the“rigid block lateral extrusion”1model.
