This study proposes a method for measuring the operational current of high temperature superconducting(HTS)non‐insulation(NI)closed‐loop coils,which operate in the steady persistent‐current‐mode(PCM).HTS NI closed...This study proposes a method for measuring the operational current of high temperature superconducting(HTS)non‐insulation(NI)closed‐loop coils,which operate in the steady persistent‐current‐mode(PCM).HTS NI closed‐loop coils are promising for many easily‐quenching direct‐current(DC)applications,where their performance is determined by magnetomotive forces,total number of turns,and dimensions.As the primary interface parameter in an application system,the operational current must be accurately and rapidly measured.Generally,this is achieved by dividing the measured magnetic field by the coil constant.However,even if the influence of the screening current induced field(SCIF)is not considered,existing methods for the coil constant may be disturbed by the performance and location of Hall sensors,or experience a long measuring period.Therefore,a relatively accurate and fast method is proposed in this study,which is based on adjusting the output current of the adjustable power supply and monitoring the coil voltage as an indicator.The proposed method was validated through experiments and simulations using an equivalent circuit model coupled with a finite element method(FEM)model,and its current accuracy can be equivalent to the resolution of the employed power supply.It was demonstrated that this method reduced the requirements for Hall sensor’s performance and location,and has a more reliable accuracy in contrast to the simulation method.Compared to the experimentally conventional method,the proposed method presents a significantly faster speed.The impact of the SCIF was considered and proven to be negligible for the tested pancake coils.Even for coils whose coil constant vibrates owing to the SCIF,this method can be adapted to directly measure various operational currents.Furthermore,it was demonstrated that the measurement error can be influenced by the current discrepancy among turns when the coil is not in the steady PCM,and a procedure for reducing this error was proposed.展开更多
Main observation and conclusion Herein,we report a rational construction of Au@Ag/C@SiO_(2)system with Au@Ag core-shell nanoparticles(NPs)as a promising photocatalyst based on the plasmonic coupling effect for the fir...Main observation and conclusion Herein,we report a rational construction of Au@Ag/C@SiO_(2)system with Au@Ag core-shell nanoparticles(NPs)as a promising photocatalyst based on the plasmonic coupling effect for the first time towards the photoreduction of nitroaromatic compounds under visible light.The combination and elaborate construction of Au@Ag NPs,carbon microspheres and mesoporous SiO_(2)shell can endow this system with several outstanding features towards photocatalytic reaction.Firstly,the broadband light harvesting across ultraviolet-visible-near infrared(UV-vis-NIR)region can be achieved due to the comprehensive effect of surface plasmonic resonance(SPR)coupling model of Au and Ag,near-field scattering light of carbon microspheres and light reflecting effect of SiO_(2)shell,resulting in the production of more electrons for phororeduction reaction.Secondly,the carbon microspheres in Au@Ag/C@SiO_(2)system possess electron-rich property due to their strong electron-withdrawing ability,which can act as the Lewis acid and Lewis basic site,and promote the stepwise hydrogenation of nitrobenzene.Thirdly,Au@Ag/C@SiO_(2)exhibits excellent reusability because of the protection of SiO_(2)shell,which restricts metal NPs inside the spheres and protects them from aggregation and being lost during reaction process.Our present work demonstrates the significance of construction of hybrid nanostructures based on the plasmonic coupling effect,which can be a promising approach to design efficient photocatalyst towards organic synthesis under visible light.展开更多
Zinc indium sulfide (ZnIn_(2)S_(4)),a novel photocatalyst,has attracted considerable attention and been extensively studied over the past few years owing to its various advantages such as nontoxicity,structural stabil...Zinc indium sulfide (ZnIn_(2)S_(4)),a novel photocatalyst,has attracted considerable attention and been extensively studied over the past few years owing to its various advantages such as nontoxicity,structural stability,easy availability,suitable band gap and fascinating photocatalytic activity.This review mainly focuses on the recent state-of-art progress of ZnIn_(2)S_(4)-based photocatalysts.First,we briefly introduced preparation methods of ZnIn_(2)S_(4) with diverse morphological structures.Then,considering the photocatalytic activity of pristine ZnIn_(2)S_(4) would be confined by rapid recombination of photo-generated electronhole pairs and limited light absorption range,different modulation strategies such as layer and size control,doping,vacancy engineering and hetero-nanostructures were expounded in detail.Afterwards,the applications of ZnIn_(2)S_(4) in various fields such as H_(2) production,CO_(2) reduction,value-added products synthesis,pollutant purification and N_(2) fixation are clearly summarized.In the end,we sorted out the conclusions and outlook,aiming to provide some new insights for this fascinating material.展开更多
Fe-based catalysts have been discovered as the best elementary metal-based heterogeneous catalysts for the ammonia synthesis in industrial application during the last century.Herein,a novel and scalable strategy is de...Fe-based catalysts have been discovered as the best elementary metal-based heterogeneous catalysts for the ammonia synthesis in industrial application during the last century.Herein,a novel and scalable strategy is developed to prepare the K-promoted Fe/C catalyst with extremely high Fe loading (> 50 wt.%) through pyrolysis of the Fe-based metal-organic framework (MOF) xerogel.The obtained K-Fe/C catalysts exhibited superior activity and stability towards ammonia synthesis.The weight-specific reaction rate of Fe/C with K2O as promoter can achieve 12.4 mmol·g-1·h-1 at 350 ℃ and 30.4 mmol·g-1·h-1 at 400 ℃,approximately four and two times higher than that of the commercial fused-iron catalyst (3.4 mmol·g-1·h-1 at 350 ℃ and 16.7 mmol·g-1·h-1 at 400 ℃) under the same condition,respectively.The excellent performance of K-Fe/C can be ascribed to the inherited structure derived from the metal-organic frame precursors and the promotion of potassium,which can modify the binding energy of reactant molecules on the Fe surface,transfer electrons to iron for effective activation of nitrogen,prevent agglomeration of Fe nanoparticle (NPs) and restrain side reaction of carbon matrix to methane.展开更多
The dysfunction of Na^(+)-Cl^(−)cotransporter(NCC)caused by mutations in solute carrier family12,member 3 gene(SLC12A3)primarily causes Gitelman syndrome(GS).In identifying the pathogenicity of R158Q and G212S variant...The dysfunction of Na^(+)-Cl^(−)cotransporter(NCC)caused by mutations in solute carrier family12,member 3 gene(SLC12A3)primarily causes Gitelman syndrome(GS).In identifying the pathogenicity of R158Q and G212S variants of SLC12A3,we evaluated the pathogenicity by bioinformatic,expression,and localization analysis of two variants from a patient in our cohort.The prediction of mutant protein showed that p.R158Q and p.G212S could alter protein’s three-dimensional structure.Western blot showed a decrease of mutant Ncc.Immunofluorescence of the two mutations revealed a diffuse positive staining below the plasma membrane.Meanwhile,we conducted a compound heterozygous model—Ncc^(R156Q/G210S)mice corresponding to human NCC R158Q/G212S.Ncc^(R156Q/G210S)mice clearly exhibited typical GS features,including hypokalemia,hypomagnesemia,and increased fractional excretion of K^(+)and Mg^(2+)with a normal blood pressure level,which made Ncc^(R156Q/G210S)mice an optimal mouse model for further study of GS.A dramatic decrease and abnormal localization of the mutant Ncc in distal convoluted tubules contributed to the phenotype.The hydrochlorothiazide test showed a loss of function of mutant Ncc in Ncc^(R156Q/G210S)mice.These findings indicated that R158Q and G212S variants of SLC12A3 were pathogenic variants of GS.展开更多
Background:Building brain reserves before dementia onset could represent a promising strategy to prevent Alzheimer’s disease(AD),while how to initiate early cognitive stimulation is unclear.Given that the immature br...Background:Building brain reserves before dementia onset could represent a promising strategy to prevent Alzheimer’s disease(AD),while how to initiate early cognitive stimulation is unclear.Given that the immature brain is more sensitive to environmental stimuli and that brain dynamics decrease with ageing,we reasoned that it would be effective to initiate cognitive stimulation against AD as early as the fetal period.Methods:After conception,maternal AD transgenic mice(3×Tg AD)were exposed to gestational environment enrichment(GEE)until the day of delivery.The cognitive capacity of the offspring was assessed by the Morris water maze and contextual fear-conditioning tests when the offspring were raised in a standard environment to 7 months of age.Western blotting,immunohistochemistry,real-time PCR,immunoprecipitation,chromatin immunoprecipitation(ChIP)assay,electrophysiology,Golgi staining,activity assays and sandwich ELISA were employed to gain insight into the mechanisms underlying the beneficial effects of GEE on embryos and 7–10-month-old adult offspring.Results:We found that GEE markedly preserved synaptic plasticity and memory capacity with amelioration of hallmark pathologies in 7–10-m-old AD offspring.The beneficial effects of GEE were accompanied by global histone hyperacetylation,including those at bdnf promoter-binding regions,with robust BDNF mRNA and protein expression in both embryo and progeny hippocampus.GEE increased insulin-like growth factor 1(IGF1)and activated its receptor(IGF1R),which phosphorylates Ca^(2+)/calmodulin-dependent kinase IV(CaMKIV)at tyrosine sites and triggers its nuclear translocation,subsequently upregulating histone acetyltransferase(HAT)and BDNF transcription.The upregulation of IGF1 mimicked the effects of GEE,while IGF1R or HAT inhibition during pregnancy abolished the GEE-induced CaMKIV-dependent histone hyperacetylation and BDNF upregulation.Conclusions:These findings suggest that activation of IGF1R/CaMKIV/HAT/BDNF signaling by gestational environment enrichment may serve as a promising strategy to delay AD progression.展开更多
This paper presents an approach to achieve broadband absorption and temperature resistance using ceramic sub-strates.A specially formulated slurry suitable for additive manufacturing technology was developed to fabric...This paper presents an approach to achieve broadband absorption and temperature resistance using ceramic sub-strates.A specially formulated slurry suitable for additive manufacturing technology was developed to fabricate ceramic substrates with lattice structures.The lattice structure not only reduces the weight of the absorber but also facilitates the broadening of the absorption bandwidth.The experimental results demonstrate that the pro-posed structure exhibits absorption rates exceeding 88%within the frequency range of 19.9-30.41 GHz,with a relative absorption bandwidth of 41.8%under normal incidence.Furthermore,the absorber’s performance was assessed under high temperatures of up to 200℃,revealing absorption spectra that closely match the initially measured spectrum.Additive-manufactured ceramic lattice structures present a promising avenue for designing multifunctional broadband microwave absorbers capable of withstanding elevated temperatures.展开更多
基金supported by National Natural Science Foundation of China(NSFC)under project 51977130.
文摘This study proposes a method for measuring the operational current of high temperature superconducting(HTS)non‐insulation(NI)closed‐loop coils,which operate in the steady persistent‐current‐mode(PCM).HTS NI closed‐loop coils are promising for many easily‐quenching direct‐current(DC)applications,where their performance is determined by magnetomotive forces,total number of turns,and dimensions.As the primary interface parameter in an application system,the operational current must be accurately and rapidly measured.Generally,this is achieved by dividing the measured magnetic field by the coil constant.However,even if the influence of the screening current induced field(SCIF)is not considered,existing methods for the coil constant may be disturbed by the performance and location of Hall sensors,or experience a long measuring period.Therefore,a relatively accurate and fast method is proposed in this study,which is based on adjusting the output current of the adjustable power supply and monitoring the coil voltage as an indicator.The proposed method was validated through experiments and simulations using an equivalent circuit model coupled with a finite element method(FEM)model,and its current accuracy can be equivalent to the resolution of the employed power supply.It was demonstrated that this method reduced the requirements for Hall sensor’s performance and location,and has a more reliable accuracy in contrast to the simulation method.Compared to the experimentally conventional method,the proposed method presents a significantly faster speed.The impact of the SCIF was considered and proven to be negligible for the tested pancake coils.Even for coils whose coil constant vibrates owing to the SCIF,this method can be adapted to directly measure various operational currents.Furthermore,it was demonstrated that the measurement error can be influenced by the current discrepancy among turns when the coil is not in the steady PCM,and a procedure for reducing this error was proposed.
基金supported by the National Natural Science Foundation of China(Nos.21872104 and 21501131)the Science and Technology Commission Foundation of Tianjin(18JCQNJC76200)+2 种基金the Natural Science Foundation of Tianjin for Distinguished Young Scholar(20JGQJC00150)CASC Qian Xuesen Innovation Fund for Young ScientistsTianjin Research Innovation Project for Postgraduate Students.
文摘Main observation and conclusion Herein,we report a rational construction of Au@Ag/C@SiO_(2)system with Au@Ag core-shell nanoparticles(NPs)as a promising photocatalyst based on the plasmonic coupling effect for the first time towards the photoreduction of nitroaromatic compounds under visible light.The combination and elaborate construction of Au@Ag NPs,carbon microspheres and mesoporous SiO_(2)shell can endow this system with several outstanding features towards photocatalytic reaction.Firstly,the broadband light harvesting across ultraviolet-visible-near infrared(UV-vis-NIR)region can be achieved due to the comprehensive effect of surface plasmonic resonance(SPR)coupling model of Au and Ag,near-field scattering light of carbon microspheres and light reflecting effect of SiO_(2)shell,resulting in the production of more electrons for phororeduction reaction.Secondly,the carbon microspheres in Au@Ag/C@SiO_(2)system possess electron-rich property due to their strong electron-withdrawing ability,which can act as the Lewis acid and Lewis basic site,and promote the stepwise hydrogenation of nitrobenzene.Thirdly,Au@Ag/C@SiO_(2)exhibits excellent reusability because of the protection of SiO_(2)shell,which restricts metal NPs inside the spheres and protects them from aggregation and being lost during reaction process.Our present work demonstrates the significance of construction of hybrid nanostructures based on the plasmonic coupling effect,which can be a promising approach to design efficient photocatalyst towards organic synthesis under visible light.
基金financially supported by the National Funds for Distinguished Young Scientists (No. 61825503)the Natural Science of China (Nos. 51902101, 61775101 and 61804082)+1 种基金Natural Science of Jiangsu Province (No. BK20201381)Science of Nanjing University of Posts and Telecommunications (No. NY219144)。
文摘Zinc indium sulfide (ZnIn_(2)S_(4)),a novel photocatalyst,has attracted considerable attention and been extensively studied over the past few years owing to its various advantages such as nontoxicity,structural stability,easy availability,suitable band gap and fascinating photocatalytic activity.This review mainly focuses on the recent state-of-art progress of ZnIn_(2)S_(4)-based photocatalysts.First,we briefly introduced preparation methods of ZnIn_(2)S_(4) with diverse morphological structures.Then,considering the photocatalytic activity of pristine ZnIn_(2)S_(4) would be confined by rapid recombination of photo-generated electronhole pairs and limited light absorption range,different modulation strategies such as layer and size control,doping,vacancy engineering and hetero-nanostructures were expounded in detail.Afterwards,the applications of ZnIn_(2)S_(4) in various fields such as H_(2) production,CO_(2) reduction,value-added products synthesis,pollutant purification and N_(2) fixation are clearly summarized.In the end,we sorted out the conclusions and outlook,aiming to provide some new insights for this fascinating material.
基金Acknowledgements This work was financially supported by the National Natural Science Foundation of China （Nos. 21473003 and 21303119） and the National Basic Research Program of China （No. 2013CB933100）. C. Y. acknowledges the financial support of China Postdoctoral Science Foundation （No. 2015M580011）. XAS analysis was performed at the Beijing Synchrotron Radiation Fadlity.
基金This work was financially supported by the National Key Research and Development Program of China(Nos.2017YFB0602200 and 2017YFA0206701)National Program for Support of Top-notch Young Professionals,Changjiang Scholar Program and the National Natural Science Foundation of China(Nos.21725301,91645115,21673273,21473003,21872104,and 21821004)The XPS experiments were conducted at Lab of Multitechniques Electron&Ion Spectrometer for Surface Analysis of Peking University.We thank Jinglin Xie for XPS data discussion.
文摘Fe-based catalysts have been discovered as the best elementary metal-based heterogeneous catalysts for the ammonia synthesis in industrial application during the last century.Herein,a novel and scalable strategy is developed to prepare the K-promoted Fe/C catalyst with extremely high Fe loading (> 50 wt.%) through pyrolysis of the Fe-based metal-organic framework (MOF) xerogel.The obtained K-Fe/C catalysts exhibited superior activity and stability towards ammonia synthesis.The weight-specific reaction rate of Fe/C with K2O as promoter can achieve 12.4 mmol·g-1·h-1 at 350 ℃ and 30.4 mmol·g-1·h-1 at 400 ℃,approximately four and two times higher than that of the commercial fused-iron catalyst (3.4 mmol·g-1·h-1 at 350 ℃ and 16.7 mmol·g-1·h-1 at 400 ℃) under the same condition,respectively.The excellent performance of K-Fe/C can be ascribed to the inherited structure derived from the metal-organic frame precursors and the promotion of potassium,which can modify the binding energy of reactant molecules on the Fe surface,transfer electrons to iron for effective activation of nitrogen,prevent agglomeration of Fe nanoparticle (NPs) and restrain side reaction of carbon matrix to methane.
基金supported by grants from the National Natural Science Foundation of China(No.81974124)Special Funds for Taishan Scholar Project(No.tsqn20161071)Academic Promotion Program of Shandong First Medical University(No.2019RC015).
文摘The dysfunction of Na^(+)-Cl^(−)cotransporter(NCC)caused by mutations in solute carrier family12,member 3 gene(SLC12A3)primarily causes Gitelman syndrome(GS).In identifying the pathogenicity of R158Q and G212S variants of SLC12A3,we evaluated the pathogenicity by bioinformatic,expression,and localization analysis of two variants from a patient in our cohort.The prediction of mutant protein showed that p.R158Q and p.G212S could alter protein’s three-dimensional structure.Western blot showed a decrease of mutant Ncc.Immunofluorescence of the two mutations revealed a diffuse positive staining below the plasma membrane.Meanwhile,we conducted a compound heterozygous model—Ncc^(R156Q/G210S)mice corresponding to human NCC R158Q/G212S.Ncc^(R156Q/G210S)mice clearly exhibited typical GS features,including hypokalemia,hypomagnesemia,and increased fractional excretion of K^(+)and Mg^(2+)with a normal blood pressure level,which made Ncc^(R156Q/G210S)mice an optimal mouse model for further study of GS.A dramatic decrease and abnormal localization of the mutant Ncc in distal convoluted tubules contributed to the phenotype.The hydrochlorothiazide test showed a loss of function of mutant Ncc in Ncc^(R156Q/G210S)mice.These findings indicated that R158Q and G212S variants of SLC12A3 were pathogenic variants of GS.
基金This work was supported in part by grants from the NSFC(91632305,91632111,31730035 and 81721005)by the Ministry of Science and Technology of China(2016YFC1305800).
文摘Background:Building brain reserves before dementia onset could represent a promising strategy to prevent Alzheimer’s disease(AD),while how to initiate early cognitive stimulation is unclear.Given that the immature brain is more sensitive to environmental stimuli and that brain dynamics decrease with ageing,we reasoned that it would be effective to initiate cognitive stimulation against AD as early as the fetal period.Methods:After conception,maternal AD transgenic mice(3×Tg AD)were exposed to gestational environment enrichment(GEE)until the day of delivery.The cognitive capacity of the offspring was assessed by the Morris water maze and contextual fear-conditioning tests when the offspring were raised in a standard environment to 7 months of age.Western blotting,immunohistochemistry,real-time PCR,immunoprecipitation,chromatin immunoprecipitation(ChIP)assay,electrophysiology,Golgi staining,activity assays and sandwich ELISA were employed to gain insight into the mechanisms underlying the beneficial effects of GEE on embryos and 7–10-month-old adult offspring.Results:We found that GEE markedly preserved synaptic plasticity and memory capacity with amelioration of hallmark pathologies in 7–10-m-old AD offspring.The beneficial effects of GEE were accompanied by global histone hyperacetylation,including those at bdnf promoter-binding regions,with robust BDNF mRNA and protein expression in both embryo and progeny hippocampus.GEE increased insulin-like growth factor 1(IGF1)and activated its receptor(IGF1R),which phosphorylates Ca^(2+)/calmodulin-dependent kinase IV(CaMKIV)at tyrosine sites and triggers its nuclear translocation,subsequently upregulating histone acetyltransferase(HAT)and BDNF transcription.The upregulation of IGF1 mimicked the effects of GEE,while IGF1R or HAT inhibition during pregnancy abolished the GEE-induced CaMKIV-dependent histone hyperacetylation and BDNF upregulation.Conclusions:These findings suggest that activation of IGF1R/CaMKIV/HAT/BDNF signaling by gestational environment enrichment may serve as a promising strategy to delay AD progression.
基金supported by National Natural Science Foundation of China(Grant Nos.12102444,52005494).
文摘This paper presents an approach to achieve broadband absorption and temperature resistance using ceramic sub-strates.A specially formulated slurry suitable for additive manufacturing technology was developed to fabricate ceramic substrates with lattice structures.The lattice structure not only reduces the weight of the absorber but also facilitates the broadening of the absorption bandwidth.The experimental results demonstrate that the pro-posed structure exhibits absorption rates exceeding 88%within the frequency range of 19.9-30.41 GHz,with a relative absorption bandwidth of 41.8%under normal incidence.Furthermore,the absorber’s performance was assessed under high temperatures of up to 200℃,revealing absorption spectra that closely match the initially measured spectrum.Additive-manufactured ceramic lattice structures present a promising avenue for designing multifunctional broadband microwave absorbers capable of withstanding elevated temperatures.
