A novel GO modified g-C_(3)N_(4) nanosheets/flower-like BiOBr hybrid photocatalyst is fabricated by a facile method.The characterization results reveal that wrinkled GO is deposited between g-C_(3)N_(4) nanosheets and...A novel GO modified g-C_(3)N_(4) nanosheets/flower-like BiOBr hybrid photocatalyst is fabricated by a facile method.The characterization results reveal that wrinkled GO is deposited between g-C_(3)N_(4) nanosheets and flower-like BiOBr forming a Z-scheme heterojunction.As a mediator,plicate GO plays a positive role in prompting photogene rated electrons transfe rring through its sizeable 2 D/2 D contact surface area.The g-C3 N4/GO/BiOBr hybrid displays a superior photocatalytic ability to g-C_(3)N_(4) and BiOBr in photodegrading tetracycline(TC),whose removal efficiency could reach 96%within 2 h.Besides,g-C_(3)N_(4)/GO/BiOBr composite can reduce Cr(Ⅵ),and simultaneously treat TC and Cr(Ⅵ)combination contaminant under the visible light The g-C_(3)N_(4)/GO/BiOBr ternary composite also exhibits satisfactory stability and reusability after four cycling experiments.Further,a feasible mechanism related to the photocatalytic process of gC_(3)N_(4)/GO/BiOBr is put forward.This study offers a te rnary hybrid photocatalyst with eco-friendliness and hopeful application in water pollution.展开更多
Articular cartilage injury induced by collision or trauma is a common sports-related condition that may progress to pain,dysfunction,and secondary osteoarthritis(OA).Limited by self-renewal potential,cartilage regener...Articular cartilage injury induced by collision or trauma is a common sports-related condition that may progress to pain,dysfunction,and secondary osteoarthritis(OA).Limited by self-renewal potential,cartilage regeneration faces a quandary while bio-inspired novel strategies are urgently required.In this study,by a soft freezing method and surface modification technique,a multi-functional silk fibroin(SF)plus gelatin methacrylate(GelMA)scaffold laden with melatonin(MT)was prepared.SF-GelMA@MT scaffold demonstrated enhanced biomechanical characteristics and long-acting melatonin release.In vitro treatment with SF-GelMA@MT induced the synthesis of cartilage extracellular matrix(ECM)components.Mechanistically,sustained release of melatonin yielded robust chondroprotective effects via improving mitochondrial polarization and antioxidant properties.SF-GelMA@MT implantation boosted cartilage renascence in a full-thickness cartilage defect model via mitochondria-associated sirtuins 1(SIRT1)-superoxide dismutase 2(SOD2)signaling pathway in vivo.In summary,this research proposed a welldesigned bionic composite scaffold that promotes cartilage regeneration via mitochondrial function enhancement,which is of tremendous potential for cartilage tissue engineering.展开更多
Solar-driven photoelectrochemical(PEC)water splitting systems are highly promising for converting solar energy into clean and sustainable chemical energy.In such PEC systems,an integrated photoelectrode incorporates a...Solar-driven photoelectrochemical(PEC)water splitting systems are highly promising for converting solar energy into clean and sustainable chemical energy.In such PEC systems,an integrated photoelectrode incorporates a light harvester for absorbing solar energy,an interlayer for transporting photogenerated charge carriers,and a co-catalyst for triggering redox reactions.Thus,understanding the correlations between the intrinsic structural properties and functions of the photoelectrodes is crucial.Here we critically examine various 2D layered photoanodes/photocathodes,including graphitic carbon nitrides,transition metal dichalcogenides,layered double hydroxides,layered bismuth oxyhalide nanosheets,and MXenes,combined with advanced nanocarbons(carbon dots,carbon nanotubes,graphene,and graphdiyne)as co-catalysts to assemble integrated photoelectrodes for oxygen evolution/hydrogen evolution reactions.The fundamental principles of PEC water splitting and physicochemical properties of photoelectrodes and the associated catalytic reactions are analyzed.Elaborate strategies for the assembly of 2D photoelectrodes with nanocarbons to enhance the PEC performances are introduced.The mechanisms of interplay of 2D photoelectrodes and nanocarbon co-catalysts are further discussed.The challenges and opportunities in the field are identified to guide future research for maximizing the conversion efficiency of PEC water splitting.展开更多
Electroreduction of CO_(2)shows great potential for global CO_(2)utilization and uptake when collaborated with renewable electricity.Recent advances have been achieved in fundamental understanding and electrocatalyst ...Electroreduction of CO_(2)shows great potential for global CO_(2)utilization and uptake when collaborated with renewable electricity.Recent advances have been achieved in fundamental understanding and electrocatalyst development for CO_(2)electroreduction.We think this research area has progressed to the stage where significant efforts can focus on translating the obtained knowledge to the development of largescale electrolyzers,which have the potential to accelerate the transition of the current energy system into a sustainable and zero-carbon emission energy structure.In this perspective paper,we first critically evaluate the advancement of vapor-feed devices that use CO_(2)as reactants,from the point of view of industry applications.Then,by carefully comparing their performance to the state-of-the-art water electrolyzers which are well-established technology providing realistic performance targets,we looped back and discussed the remaining challenges including electrode catalysts,reaction conditions,mass transporting,membrane,device durability,operation mode,and so on.Finally,we provide perspectives on the challenges and suggest opportunities for generating fundamental knowledge and achieving technological progress toward the development of practical CO_(2)electrolyzers for the goal of building lowcarbon or/and net carbon-free economies.展开更多
BACKGROUND The effect of the number of lymph node dissections(LNDs)during radical resection for colorectal cancer(CRC)on overall survival(OS)remains controver-sial.AIM To investigate the association between the number...BACKGROUND The effect of the number of lymph node dissections(LNDs)during radical resection for colorectal cancer(CRC)on overall survival(OS)remains controver-sial.AIM To investigate the association between the number of LNDs and OS in patients with tumor node metastasis(TNM)stage Ⅰ–Ⅱ CRC undergoing radical resection.METHODS Patients who underwent radical resection for CRC at a single-center hospital between January 2011 and December 2021 were retrospectively analyzed.Cox regression analyses were performed to identify the independent predictors of OS at different T stages.RESULTS A total of 2850 patients who underwent laparoscopic radical resection for CRC were enrolled.At stage T1,age[P<0.01,hazard ratio(HR)=1.075,95%confidence interval(CI):1.019-1.134]and tumour size(P=0.021,HR=3.635,95%CI:1.210-10.917)were independent risk factors for OS.At stage T2,age(P<0.01,HR=1.064,95%CI:1.032-1.098)and overall complications(P=0.012,HR=2.297,95%CI:1.200-4.397)were independent risk factors for OS.At stage T3,only age(P<0.01,HR=1.047,95%CI:1.027-1.066)was an independent risk factor for OS.At stage T4,age(P<0.01,HR=1.057,95%CI:1.039-1.075)and body mass index(P=0.034,HR=0.941,95%CI:0.890-0.995)were independent risk factors for OS.However,there was no association between LNDs and OS in stages Ⅰ and Ⅱ.CONCLUSION The number of LDNs did not affect the survival of patients with TNM stages Ⅰ and Ⅱ CRC.Therefore,insufficient LNDs should not be a cause for alarm during the surgery.展开更多
Objective:To investigate the prevalence of emotional and behavioral problems and related factors of left-behind children in impoverished rural China(mainly in thefirst grade of junior high school).Methods:A cross-sect...Objective:To investigate the prevalence of emotional and behavioral problems and related factors of left-behind children in impoverished rural China(mainly in thefirst grade of junior high school).Methods:A cross-sectional survey of rural households in 27 poverty-stricken counties in 12 provinces across China was conducted using the Strengths and Difficulties Questionnaire(SDQ).Results:The prevalence of emotional and behavioral problems in left-behind children was 11.7%,and that of non-left-behind children was 8.9%.There was statistical difference between the two groups(P<0.01).There are no differences between the two groups in terms of the various factors of SDQ.The incidence of insomnia in the left-behind group was 58.3%,which was higher than that in the non-left-behind group 50.9%(P<0.01);loneliness(62.1%vs.51.8%,P<0.01);running away from home(23.1%vs.18.8%,P<0.01),and self-injury behavior(16.8%vs.12.2%,P<0.01).Left-behind children are more likely to have negative psychological feelings including insomnia,loneliness,self-injury,and run away from home.They also experienced more bullying including maliciously teased by peers,intentionally excluded or isolated,physically threatened or intimidated.All of these factors are associated with their abnormal emotional and behavioural development.Conclusion:The incidence of emotional and behavioral problems of left-behind children in rural areas in poverty-stricken areas is significantly higher than that of non-left-behind children;Logistic regression analysis showed that bullying behavior and abnormal psychological characteristics are significantly associated with left-behind adolescents abnormal emotional and behavioral development.展开更多
Reversible protonic ceramic electrochemical cells(R-PCECs)demonstrate great feasibility for efficient energy storage and conversion.One critical challenge for the development of R-PCECs is the design of novel air elec...Reversible protonic ceramic electrochemical cells(R-PCECs)demonstrate great feasibility for efficient energy storage and conversion.One critical challenge for the development of R-PCECs is the design of novel air electrodes with the characteristics of high catalytic activity and acceptable durability.Here,we report a donor doping of Hf into the B-site of a cobalt-based double perovskite with a nominal formula of PrBa_(0.8)Ca_(0.2)Co_(1.9)Hf_(0.1)O_(5tδ)(PBCCHf_(0.1)),which is naturally reconfigured to a double perovskite PrBa_(0.8-x)Ca_(0.2)Co_(1.9)Hf_(0.1)-xO5tδ(PBCCHf_(0.1)-x)backbone and nano-sized BaHfO3(BHO)on the surface of PBCCHf_(0.1)x.The air electrode demonstrates enhanced catalytic activity and durability(a stable polarization resistance of 0.269Ωcm2 for~100 h at 600℃),due likely to the fast surface exchange process and bulk diffusion process.When employed as an air electrode of R-PCECs,a cell with PBCCHf_(0.1) air electrode demonstrates encouraging performances in modes of the fuel cell(FC)and electrolysis(EL)at 600℃:a peak power density of 0.998 W cm^(-2)and a current density of1.613 A cm^(-2)at 1.3 V(with acceptable Faradaic efficiencies).More importantly,the single-cell with PBCCHf_(0.1) air electrode demonstrates good cycling stability,switching back and forth from FC mode to EL mode0.5 A cm^(-2)for 200 h and 50 cycles.展开更多
Differential electrochemical mass spectrometry(DEMS)is one of the most powerful techniques for both the mechanistic and kinetic study of complicated electrocatalytic reactions.It can provide information on the nature ...Differential electrochemical mass spectrometry(DEMS)is one of the most powerful techniques for both the mechanistic and kinetic study of complicated electrocatalytic reactions.It can provide information on the nature and yields of the products generated,their production rate,and the structure-activity relationship between the electrocatalysts and the target reactions.The precise calibration of the mass signal is a prerequisite for the accurate evaluation of reaction kinetics.In this work,we use the oxidation reactions of CO and HCOOH to demonstrate how certain conditions,such as the flow rate and solution composition,affect the collection efficiency and ionization probability of the species to be detected.These parameters can affect the determination of the mass calibration constant and the accuracy of the subsequent quantitative DEMS analysis.We show the relationship between the mass calibration constant and the flow rate,and provide strategies for eliminating this and the related problems.展开更多
Bimetallic catalysts can improve CO2 reduction efficiency via the combined properties of two metals.CuPd shows enhanced CO2 reduction activity compared to copper alone.Using differential electrochemical mass spectrome...Bimetallic catalysts can improve CO2 reduction efficiency via the combined properties of two metals.CuPd shows enhanced CO2 reduction activity compared to copper alone.Using differential electrochemical mass spectrometry(DEMS)and electrochemical infrared(IR)spectroscopy,volatile products and adsorbed intermediates were measured during CO2 and CO reduction on Cu and CuPd.The IR band corresponding to adsorbed CO appears 300 mV more positive on CuPd than that on Cu,indicating acceleration of CO2 reduction to CO.Electrochemical IR spectroscopy measurements in CO-saturated solutions reveal similar potentials for CO adsorption and CO3^2-desorption on CuPd and Cu,indicating that CO adsorption is controlled by desorption of CO3^2-.DEMS measurements carried out during CO reduction at both electrodes showed that the onset potential for reduction of CO to CH4 and CH3OH on CuPd is about 200 mV more positive than that on Cu.We attribute these improvements to interaction of Cu and Pd,which shifts the d-band center of the Cu sites.展开更多
This article did a research about exhaust gas constituent inside the catalytic combustion furnace with Pd-based honeycomb monoliths of lean natural gas-air mixtures and discussed the feature of the exhaust gas. In add...This article did a research about exhaust gas constituent inside the catalytic combustion furnace with Pd-based honeycomb monoliths of lean natural gas-air mixtures and discussed the feature of the exhaust gas. In addition, the near-zero pollutant emissions of catalytic combustion burner was proved by a test report provided by NIM. From a low-carbon prospective, the application prospect of catalytic combustion furnace was展开更多
Production of green hydrogen through water electrolysis powered by renewable energy sources has garnered increasing attention as an attractive strategy for the storage of clean and sustainable energy.Among various ele...Production of green hydrogen through water electrolysis powered by renewable energy sources has garnered increasing attention as an attractive strategy for the storage of clean and sustainable energy.Among various electrolysis technologies,the emerging anion exchange membrane water electrolyser(AEMWE)exhibits the most potential for green hydrogen production,offering a potentially costeffective and sustainable approach that combines the advantages of high current density and fast start from proton exchange membrane water electrolyser(PEMWE)and low-cost catalyst from traditional alkaline water electrolyser(AWE)systems.Due to its relatively recent emergence over the past decade,a series of efforts are dedicated to improving the electrochemical reaction performance to accelerate the development and commercialization of AEMWE technology.A catalytic electrode comprising a gas diffusion layer(GDL)and a catalyst layer(CL)is usually called a gas diffusion electrode(GDE)that serves as a fundamental component within AEMWE,and also plays a core role in enhancing mass transfer during the electrolysis process.Inside the GDEs,bubbles nucleate and grow within the CL and then are transported through the GDL before eventually detaching to enter the electrolyte in the flow field.The transfer processes of water,gas bubbles,charges,and ions are intricately influenced by bubbles.This phenomenon is referred to as bubble-associated mass transfer.Like water management in fuel cells,effective bubble management is crucial in electrolysers,as its failure can result in various overpotential losses,such as activation losses,ohmic losses,and mass transfer losses,ultimately degrading the AEMWE performance.Despite significant advancements in the development of new materials and techniques in AEMWE,there is an urgent need for a comprehensive discussion focused on GDEs,with a particular emphasis on bubbleassociated mass transfer phenomena.This review aims to highlight recent findings regarding mass transfer in GDEs,particularly the impacts of bubble accumulation;and presents the latest advancements in designing CLs and GDLs to mitigate bubble-related issues.It is worth noting that a series of innovative bubble-free-GDE designs for water electrolysis are also emphasized in this review.This review is expected to be a valuable reference for gaining a deeper understanding of bubble-related mass transfer,especially the complex bubble behavior associated with GDEs,and for developing innovative practical strategies to advance AEMWE for green hydrogen production.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21667019,22066017,and 22002057)the Key Project of Natural Science Foundation of Jiangxi Province(No.20171ACB20016)+11 种基金the Jiangxi Province Major Academic and Technical Leaders Cultivating Object Program(No.20172BCB22014)the Science and Technology Department of Jiangxi Province(Nos.20181BCB18003 and 20181ACG70025)the Key Laboratory of Photochemical Conversion and Optoelectronic Materials,TIPC,CSA(No.PCOM201906)the Key Project of Science and Technology Research of the Jiangxi Provincial Department of Education(Nos.DA201602063 and GJJ191044)the Aviation Science Foundation of China(No.2017ZF56020)Fujian Key Laboratory of Measurement and Control System for of Shore Environment(No.S1-KF1703)the Doctor’s Start-up Fund of Nanchang Hangkong University(No.EA201902286)the National Natural Science Foundation of China(Nos.51702284,21878270 and 21922811)Zhejiang Provincial Natural Science Foundation of China(No.LR19B060002)the Fundamental Research Funds for the Central Universitiesthe Startup Foundation for Hundred-Talent Program of Zhejiang University。
文摘A novel GO modified g-C_(3)N_(4) nanosheets/flower-like BiOBr hybrid photocatalyst is fabricated by a facile method.The characterization results reveal that wrinkled GO is deposited between g-C_(3)N_(4) nanosheets and flower-like BiOBr forming a Z-scheme heterojunction.As a mediator,plicate GO plays a positive role in prompting photogene rated electrons transfe rring through its sizeable 2 D/2 D contact surface area.The g-C3 N4/GO/BiOBr hybrid displays a superior photocatalytic ability to g-C_(3)N_(4) and BiOBr in photodegrading tetracycline(TC),whose removal efficiency could reach 96%within 2 h.Besides,g-C_(3)N_(4)/GO/BiOBr composite can reduce Cr(Ⅵ),and simultaneously treat TC and Cr(Ⅵ)combination contaminant under the visible light The g-C_(3)N_(4)/GO/BiOBr ternary composite also exhibits satisfactory stability and reusability after four cycling experiments.Further,a feasible mechanism related to the photocatalytic process of gC_(3)N_(4)/GO/BiOBr is put forward.This study offers a te rnary hybrid photocatalyst with eco-friendliness and hopeful application in water pollution.
基金supported by the National Natural Science Foundation of China(Nos.82072410,82072476 and 82072442)the Natural Science Foundation of Jiangsu Province(No.BK20220046)+1 种基金the Major Science and Technology Project of Changzhou Health Commission(No.ZD202001)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Articular cartilage injury induced by collision or trauma is a common sports-related condition that may progress to pain,dysfunction,and secondary osteoarthritis(OA).Limited by self-renewal potential,cartilage regeneration faces a quandary while bio-inspired novel strategies are urgently required.In this study,by a soft freezing method and surface modification technique,a multi-functional silk fibroin(SF)plus gelatin methacrylate(GelMA)scaffold laden with melatonin(MT)was prepared.SF-GelMA@MT scaffold demonstrated enhanced biomechanical characteristics and long-acting melatonin release.In vitro treatment with SF-GelMA@MT induced the synthesis of cartilage extracellular matrix(ECM)components.Mechanistically,sustained release of melatonin yielded robust chondroprotective effects via improving mitochondrial polarization and antioxidant properties.SF-GelMA@MT implantation boosted cartilage renascence in a full-thickness cartilage defect model via mitochondria-associated sirtuins 1(SIRT1)-superoxide dismutase 2(SOD2)signaling pathway in vivo.In summary,this research proposed a welldesigned bionic composite scaffold that promotes cartilage regeneration via mitochondrial function enhancement,which is of tremendous potential for cartilage tissue engineering.
基金the support from the National Natural Science Foundation of China(21878271,51702284,21878270,and 21961160742)the Zhejiang Provincial Natural Science Foundation of China(LR19B060002)+8 种基金the Fundamental Research Funds for the Central Universitiesthe Startup Foundation for Hundred-Talent Program of Zhejiang Universitythe Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2019R01006)Key Laboratory of Marine Materials and Related Technologies,CASZhejiang Key Laboratory of Marine Materials and Protective Technologies(2020K10)the support of the NSFC 21501138the Natural Science Foundation of Hubei Province(2019CFB556)Science Research Foundation of Wuhan Institute of Technology(K2019039)the Australian Research Council(ARC)and QUT Centre for Materials Science for partial support.
文摘Solar-driven photoelectrochemical(PEC)water splitting systems are highly promising for converting solar energy into clean and sustainable chemical energy.In such PEC systems,an integrated photoelectrode incorporates a light harvester for absorbing solar energy,an interlayer for transporting photogenerated charge carriers,and a co-catalyst for triggering redox reactions.Thus,understanding the correlations between the intrinsic structural properties and functions of the photoelectrodes is crucial.Here we critically examine various 2D layered photoanodes/photocathodes,including graphitic carbon nitrides,transition metal dichalcogenides,layered double hydroxides,layered bismuth oxyhalide nanosheets,and MXenes,combined with advanced nanocarbons(carbon dots,carbon nanotubes,graphene,and graphdiyne)as co-catalysts to assemble integrated photoelectrodes for oxygen evolution/hydrogen evolution reactions.The fundamental principles of PEC water splitting and physicochemical properties of photoelectrodes and the associated catalytic reactions are analyzed.Elaborate strategies for the assembly of 2D photoelectrodes with nanocarbons to enhance the PEC performances are introduced.The mechanisms of interplay of 2D photoelectrodes and nanocarbon co-catalysts are further discussed.The challenges and opportunities in the field are identified to guide future research for maximizing the conversion efficiency of PEC water splitting.
基金financially supported by the Zhejiang Energy Group Co.,Ltd.(ZNKJ-2021-111)Zhejiang Province key research and development program(2022C03040)。
文摘Electroreduction of CO_(2)shows great potential for global CO_(2)utilization and uptake when collaborated with renewable electricity.Recent advances have been achieved in fundamental understanding and electrocatalyst development for CO_(2)electroreduction.We think this research area has progressed to the stage where significant efforts can focus on translating the obtained knowledge to the development of largescale electrolyzers,which have the potential to accelerate the transition of the current energy system into a sustainable and zero-carbon emission energy structure.In this perspective paper,we first critically evaluate the advancement of vapor-feed devices that use CO_(2)as reactants,from the point of view of industry applications.Then,by carefully comparing their performance to the state-of-the-art water electrolyzers which are well-established technology providing realistic performance targets,we looped back and discussed the remaining challenges including electrode catalysts,reaction conditions,mass transporting,membrane,device durability,operation mode,and so on.Finally,we provide perspectives on the challenges and suggest opportunities for generating fundamental knowledge and achieving technological progress toward the development of practical CO_(2)electrolyzers for the goal of building lowcarbon or/and net carbon-free economies.
基金Chongqing Medical University Future Medical Youth Innovation Team Development Support Program,No.03030299QCW0007.
文摘BACKGROUND The effect of the number of lymph node dissections(LNDs)during radical resection for colorectal cancer(CRC)on overall survival(OS)remains controver-sial.AIM To investigate the association between the number of LNDs and OS in patients with tumor node metastasis(TNM)stage Ⅰ–Ⅱ CRC undergoing radical resection.METHODS Patients who underwent radical resection for CRC at a single-center hospital between January 2011 and December 2021 were retrospectively analyzed.Cox regression analyses were performed to identify the independent predictors of OS at different T stages.RESULTS A total of 2850 patients who underwent laparoscopic radical resection for CRC were enrolled.At stage T1,age[P<0.01,hazard ratio(HR)=1.075,95%confidence interval(CI):1.019-1.134]and tumour size(P=0.021,HR=3.635,95%CI:1.210-10.917)were independent risk factors for OS.At stage T2,age(P<0.01,HR=1.064,95%CI:1.032-1.098)and overall complications(P=0.012,HR=2.297,95%CI:1.200-4.397)were independent risk factors for OS.At stage T3,only age(P<0.01,HR=1.047,95%CI:1.027-1.066)was an independent risk factor for OS.At stage T4,age(P<0.01,HR=1.057,95%CI:1.039-1.075)and body mass index(P=0.034,HR=0.941,95%CI:0.890-0.995)were independent risk factors for OS.However,there was no association between LNDs and OS in stages Ⅰ and Ⅱ.CONCLUSION The number of LDNs did not affect the survival of patients with TNM stages Ⅰ and Ⅱ CRC.Therefore,insufficient LNDs should not be a cause for alarm during the surgery.
基金National“Twelfth Five-Year”Science and Technology Support Program(No.2012BAI01B02)Research on prevention and control of major chronic non-communicable diseases in the Ministry of Science and Technology(No.2016YFC1306100).
文摘Objective:To investigate the prevalence of emotional and behavioral problems and related factors of left-behind children in impoverished rural China(mainly in thefirst grade of junior high school).Methods:A cross-sectional survey of rural households in 27 poverty-stricken counties in 12 provinces across China was conducted using the Strengths and Difficulties Questionnaire(SDQ).Results:The prevalence of emotional and behavioral problems in left-behind children was 11.7%,and that of non-left-behind children was 8.9%.There was statistical difference between the two groups(P<0.01).There are no differences between the two groups in terms of the various factors of SDQ.The incidence of insomnia in the left-behind group was 58.3%,which was higher than that in the non-left-behind group 50.9%(P<0.01);loneliness(62.1%vs.51.8%,P<0.01);running away from home(23.1%vs.18.8%,P<0.01),and self-injury behavior(16.8%vs.12.2%,P<0.01).Left-behind children are more likely to have negative psychological feelings including insomnia,loneliness,self-injury,and run away from home.They also experienced more bullying including maliciously teased by peers,intentionally excluded or isolated,physically threatened or intimidated.All of these factors are associated with their abnormal emotional and behavioural development.Conclusion:The incidence of emotional and behavioral problems of left-behind children in rural areas in poverty-stricken areas is significantly higher than that of non-left-behind children;Logistic regression analysis showed that bullying behavior and abnormal psychological characteristics are significantly associated with left-behind adolescents abnormal emotional and behavioral development.
基金the financial support from the National Natural Science Foundation of China(Nos.22179039)the Introduced Innovative R&D Team of Guangdong(No.2021ZT09L392)+3 种基金the Fundamental Research Funds for the Central Universities(2022ZYGXZR002)Zijin Mining Group Co.,Ltd(5405-ZC-2023-00008)the Pearl River Talent Recruitment Program(2019QN01C693)the Natural Science Foundation of Guangdong Province(No.2022A1515011785).
文摘Reversible protonic ceramic electrochemical cells(R-PCECs)demonstrate great feasibility for efficient energy storage and conversion.One critical challenge for the development of R-PCECs is the design of novel air electrodes with the characteristics of high catalytic activity and acceptable durability.Here,we report a donor doping of Hf into the B-site of a cobalt-based double perovskite with a nominal formula of PrBa_(0.8)Ca_(0.2)Co_(1.9)Hf_(0.1)O_(5tδ)(PBCCHf_(0.1)),which is naturally reconfigured to a double perovskite PrBa_(0.8-x)Ca_(0.2)Co_(1.9)Hf_(0.1)-xO5tδ(PBCCHf_(0.1)-x)backbone and nano-sized BaHfO3(BHO)on the surface of PBCCHf_(0.1)x.The air electrode demonstrates enhanced catalytic activity and durability(a stable polarization resistance of 0.269Ωcm2 for~100 h at 600℃),due likely to the fast surface exchange process and bulk diffusion process.When employed as an air electrode of R-PCECs,a cell with PBCCHf_(0.1) air electrode demonstrates encouraging performances in modes of the fuel cell(FC)and electrolysis(EL)at 600℃:a peak power density of 0.998 W cm^(-2)and a current density of1.613 A cm^(-2)at 1.3 V(with acceptable Faradaic efficiencies).More importantly,the single-cell with PBCCHf_(0.1) air electrode demonstrates good cycling stability,switching back and forth from FC mode to EL mode0.5 A cm^(-2)for 200 h and 50 cycles.
基金supported by the National Natural Science Foundation of China(no.21872132,21832004,91545124)the 973 Program from the Ministry of Science and Technology of China(no.2015CB932301)。
文摘Differential electrochemical mass spectrometry(DEMS)is one of the most powerful techniques for both the mechanistic and kinetic study of complicated electrocatalytic reactions.It can provide information on the nature and yields of the products generated,their production rate,and the structure-activity relationship between the electrocatalysts and the target reactions.The precise calibration of the mass signal is a prerequisite for the accurate evaluation of reaction kinetics.In this work,we use the oxidation reactions of CO and HCOOH to demonstrate how certain conditions,such as the flow rate and solution composition,affect the collection efficiency and ionization probability of the species to be detected.These parameters can affect the determination of the mass calibration constant and the accuracy of the subsequent quantitative DEMS analysis.We show the relationship between the mass calibration constant and the flow rate,and provide strategies for eliminating this and the related problems.
基金supported by the National Natural Science Foundation of China(No.91545124 and No.21750110437)supported by the Chinese Academy of Sciences President’s International Fellowship Initiative(No.2017PM0049)。
文摘Bimetallic catalysts can improve CO2 reduction efficiency via the combined properties of two metals.CuPd shows enhanced CO2 reduction activity compared to copper alone.Using differential electrochemical mass spectrometry(DEMS)and electrochemical infrared(IR)spectroscopy,volatile products and adsorbed intermediates were measured during CO2 and CO reduction on Cu and CuPd.The IR band corresponding to adsorbed CO appears 300 mV more positive on CuPd than that on Cu,indicating acceleration of CO2 reduction to CO.Electrochemical IR spectroscopy measurements in CO-saturated solutions reveal similar potentials for CO adsorption and CO3^2-desorption on CuPd and Cu,indicating that CO adsorption is controlled by desorption of CO3^2-.DEMS measurements carried out during CO reduction at both electrodes showed that the onset potential for reduction of CO to CH4 and CH3OH on CuPd is about 200 mV more positive than that on Cu.We attribute these improvements to interaction of Cu and Pd,which shifts the d-band center of the Cu sites.
文摘This article did a research about exhaust gas constituent inside the catalytic combustion furnace with Pd-based honeycomb monoliths of lean natural gas-air mixtures and discussed the feature of the exhaust gas. In addition, the near-zero pollutant emissions of catalytic combustion burner was proved by a test report provided by NIM. From a low-carbon prospective, the application prospect of catalytic combustion furnace was
基金support from the National Natural Science Foundation of China(Grant No.52006029)the Promotion Foundation for Young Science and Technology Talents in Jilin Province(Grant No.QT202113)+2 种基金the Special Foundation of Industrial Innovation in Jilin Province(Grant No.2019C056-2)the Special Foundation for Outstanding Young Talents Training in Jilin(Grant No.20200104107)the UK EPSRC(EP/W03784X/1)。
文摘Production of green hydrogen through water electrolysis powered by renewable energy sources has garnered increasing attention as an attractive strategy for the storage of clean and sustainable energy.Among various electrolysis technologies,the emerging anion exchange membrane water electrolyser(AEMWE)exhibits the most potential for green hydrogen production,offering a potentially costeffective and sustainable approach that combines the advantages of high current density and fast start from proton exchange membrane water electrolyser(PEMWE)and low-cost catalyst from traditional alkaline water electrolyser(AWE)systems.Due to its relatively recent emergence over the past decade,a series of efforts are dedicated to improving the electrochemical reaction performance to accelerate the development and commercialization of AEMWE technology.A catalytic electrode comprising a gas diffusion layer(GDL)and a catalyst layer(CL)is usually called a gas diffusion electrode(GDE)that serves as a fundamental component within AEMWE,and also plays a core role in enhancing mass transfer during the electrolysis process.Inside the GDEs,bubbles nucleate and grow within the CL and then are transported through the GDL before eventually detaching to enter the electrolyte in the flow field.The transfer processes of water,gas bubbles,charges,and ions are intricately influenced by bubbles.This phenomenon is referred to as bubble-associated mass transfer.Like water management in fuel cells,effective bubble management is crucial in electrolysers,as its failure can result in various overpotential losses,such as activation losses,ohmic losses,and mass transfer losses,ultimately degrading the AEMWE performance.Despite significant advancements in the development of new materials and techniques in AEMWE,there is an urgent need for a comprehensive discussion focused on GDEs,with a particular emphasis on bubbleassociated mass transfer phenomena.This review aims to highlight recent findings regarding mass transfer in GDEs,particularly the impacts of bubble accumulation;and presents the latest advancements in designing CLs and GDLs to mitigate bubble-related issues.It is worth noting that a series of innovative bubble-free-GDE designs for water electrolysis are also emphasized in this review.This review is expected to be a valuable reference for gaining a deeper understanding of bubble-related mass transfer,especially the complex bubble behavior associated with GDEs,and for developing innovative practical strategies to advance AEMWE for green hydrogen production.
