Purpose–This study solves the key problem that the static level monitoring is susceptible to temperature interference and affects the accuracy in slope instability/deformation monitoring.The purpose is to develop a r...Purpose–This study solves the key problem that the static level monitoring is susceptible to temperature interference and affects the accuracy in slope instability/deformation monitoring.The purpose is to develop a reliable temperature compensation method for the system,improve the accuracy of slope stability monitoring and provide support for improving the safety and safety monitoring of engineering spoil slope and other projects.Design/methodology/approach–Combined with theoretical analysis and experimental verification,the temperature compensation method is explored.The working principle of the hydrostatic leveling monitoring system is analyzed and the data processing formula,the temperature error calculation formula and the calculation formula for eliminating the error settlement value are derived.The temperature compensation method is established and verified by the field test of the engineering spoil slope which is disturbed by a debris flow.Findings–The experimental results show that this method can reduce the error of the static level monitoring system by about 40%.The field test shows that the fluctuation of slope settlement monitoring value is reduced after temperature compensation and the monitoring value is consistent with the actual situation,which has certain practicability.Originality/value–The originality of this study is to derive a theoretical formula for quantifying/eliminating temperature errors in static leveling and to establish a practical temperature compensation method.The accuracy of the system is improved,which provides a reference for slope stability monitoring under complex environment(especially railway geotechnical engineering)and promotes the development of precision monitoring technology.展开更多
Combining water electrolysis and rechargeable battery technologies into a single system holds great promise for the co-production of hydrogen (H_(2)) and electricity.However,the design and development of such systems ...Combining water electrolysis and rechargeable battery technologies into a single system holds great promise for the co-production of hydrogen (H_(2)) and electricity.However,the design and development of such systems is still in its infancy.Herein,an integrated hydrogen-oxygen (O_(2))-electricity co-production system featuring a bipolar membrane-assisted decoupled electrolyzer and a Na-Zn ion battery was established with sodium nickelhexacyanoferrate (NaNiHCF) and Zn^(2+)/Zn as dual redox electrodes.The decoupled electrolyzer enables to produce H_(2)and O_(2)in different time and space with almost 100%Faradaic efficiency at 100 mA cm^(-2).Then,the charged NaNiHCF and Zn electrodes after the electrolysis processes formed a Na-Zn ion battery,which can generate electricity with an average cell voltage of 1.75 V at 10 m A cm^(-2).By connecting Si photovoltaics with the modular electrochemical device,a well-matched solar driven system was built to convert the intermittent solar energy into hydrogen and electric energy with a solar to hydrogen-electricity efficiency of 16.7%,demonstrating the flexible storage and conversion of renewables.展开更多
Purpose–This study is dedicated to systematically collating the distribution and utilization circumstances of geothermal resources in China.Moreover,it endeavors to formulate a comprehensive utilization scheme for ge...Purpose–This study is dedicated to systematically collating the distribution and utilization circumstances of geothermal resources in China.Moreover,it endeavors to formulate a comprehensive utilization scheme for geothermal resources during the construction and operation phases of the railway,thereby furnishing robust support and valuable reference for the holistic utilization of geothermal resources along the railway corridor.Design/methodology/approach–Through an in-depth analysis of the extant utilization of geothermal resources in China,it is discerned that the current utilization modalities are relatively rudimentary,bereft of rational planning and characterized by a low utilization rate.Concurrently,by integrating the practical requisites of railway construction and operation and conducting theoretical dissections,a comprehensive utilization plan for the construction and operation periods of railway is proffered.Findings–In light of the railway’s construction and operation characteristics,geothermal utilization models are categorized.During construction,comprehensive modalities include tunnel illumination power generation,construction area heating,tunnel antifreeze using shallow geothermal energy,tunnel pavement antifreeze and construction concrete maintenance.During operation,they comprise operation tunnel antifreeze,railway roadbed antifreeze,railway switch snow melting and deicing,geothermal power station establishment and railway hot spring health tourism planning.Originality/value–According to the characteristics and actual needs of railway construction and operation,it is of great significance to rationally utilize geothermal resources to promote the construction and operation of green railways.展开更多
Dear editor,Transcatheter aortic valve replacement (TAVR) is a safe and effective treatment for severe aortic valve stenosis and aortic regurgitation. Multiple randomized trials have proved its therapeutic advantages ...Dear editor,Transcatheter aortic valve replacement (TAVR) is a safe and effective treatment for severe aortic valve stenosis and aortic regurgitation. Multiple randomized trials have proved its therapeutic advantages in patients at any level of surgical risks.展开更多
Accurate prediction of drilling efficiency is critical for developing the earth-rock excavation schedule.The single machine learning(ML)prediction models usually suffer from problems including parameter sensitivity an...Accurate prediction of drilling efficiency is critical for developing the earth-rock excavation schedule.The single machine learning(ML)prediction models usually suffer from problems including parameter sensitivity and overfitting.In addition,the influence of environmental and operational factors is often ignored.In response,a novel stacking-based ensemble learning method taking into account the combined effects of those factors is proposed.Through multiple comparison tests,four models,e Xtreme gradient boosting(XGBoost),random forest(RF),back propagation neural network(BPNN)as the base learners,and support vector regression(SVR)as the meta-learner,are selected for stacking.Furthermore,an improved cuckoo search optimization(ICSO)algorithm is developed for hyper-parameter optimization of the ensemble model.The application to a real-world project demonstrates that the proposed method outperforms the popular single ML method XGBoost and the ensemble model optimized by particle swarm optimization(PSO),with 16.43%and 4.88%improvements of mean absolute percentage error(MAPE),respectively.展开更多
To investigate the influence of island scanning on the microstructures and mechanical properties of direct laser-deposited Ti–6 Al–4 V structures,two samples are prepared using island scanning and orthogonal success...To investigate the influence of island scanning on the microstructures and mechanical properties of direct laser-deposited Ti–6 Al–4 V structures,two samples are prepared using island scanning and orthogonal successive scanning,respectively.The microstructures,relative density,and mechanical properties of the samples prepared using these two scanning strategies are compared.Each sample exhibits columnarβ-grain morphology and basket-weave microstructure characterization.The grains of the sample prepared using island scanning are significantly finer than that prepared by orthogonal successive scanning due to faster cooling during deposition.However,the relative density of the sample prepared using island scanning was slightly smaller due to the concentration of lack-of-fusion pores at the overlap zone of the island.Tensile testing at room temperature indicates that the ultimate tensile strength and yield strength of the sample prepared using island scanning is enhanced due to finer grains,while the ductility of the sample is weakened due to defects.展开更多
Simple encapsulation of 3 nm gold nanoparticles in ordered mesoporous carbon with large pores of 17 nm and thick pore walls of 16 nm was achieved by a metal–ligand coordination assisted-selfassembly approach.Polystyr...Simple encapsulation of 3 nm gold nanoparticles in ordered mesoporous carbon with large pores of 17 nm and thick pore walls of 16 nm was achieved by a metal–ligand coordination assisted-selfassembly approach.Polystyrene-block-polyethylene-oxide(PS-b-PEO)diblock copolymer with a large molecular weight of the PS chain and mercaptopropyltrimethoxysilane were used as the template and the metal ligand,respectively.Small-angle X-ray scattering,X-ray diffraction,transmission electron microscopy,and X-ray photoelectron spectroscopy showed that monodispersed aggregation-free gold nanoparticles approximately 3 nm in size were partially embedded in the large open pore structure of the ordered mesoporous carbon.The strong coordination between the gold species and the mercapto groups and the thick porous walls increased the dispersion of the gold nanoparticles and essentially inhibited particle aggregation at 600℃.The gold nanoparticles in the ordered mesoporous carbon are active and stable in the reduction of nitroarenes involving bulky molecules using sodium borohydride as a reducing agent under ambient conditions(30℃)in water.The large interconnected pore structure facilitates the mass transfer of bulky molecules.展开更多
Electrocatalytic CO_(2) reduction reaction(CRR)is considered as a sustainable approach to converting CO_(2) into high value-added chemicals,assisting the goal of carbon peaking and carbon neutrality.Electrochemical CR...Electrocatalytic CO_(2) reduction reaction(CRR)is considered as a sustainable approach to converting CO_(2) into high value-added chemicals,assisting the goal of carbon peaking and carbon neutrality.Electrochemical CRR can be easily regulated by controlling the electrocatalyst,electrolyte,and reactor to produce various chemicals.Among different products,multi-carbon(C_(2+))products draw widespread attention for their high energy density and value along with complex reaction mechanisms.It is well recognized that*CO intermediate plays vital role in forming C_(2+)products and Cu is the only metal catalyst which can efficiently electro-reduce CO_(2) to C_(2+)products.Therefore,researchers developed many strategies to increase the amount of*CO intermediate and further enhance the performance of C_(2+)products.Recently,designing tandem electrocatalysts consisted of Cu and the materials which can convert CO_(2) to*CO intermediate has become a hotspot and achieved great achievements.In this review,we will summary the recent progress in tandem electrocatalysts for CO_(2) reduction to prepare C_(2+)products,including the origin and fundamental mechanism of tandem electrocatalysis,the strategies of catalyst design,and regulation principles.In addition,some newest findings,like Cu tandem catalysts can achieve to produce C_(2+)products,are well introduced.Finally,the remaining challenges and prospects for future development are also proposed.展开更多
Additive manufacturing(AM)has gained extensive attention and tremendous research due to its advantages of fabricating complex-shaped parts without the need of casting mold.However,distortion is a known issue for many ...Additive manufacturing(AM)has gained extensive attention and tremendous research due to its advantages of fabricating complex-shaped parts without the need of casting mold.However,distortion is a known issue for many AM technologies,which decreases the precision of as-built parts.Like fusion welding,the local high-energy input generates residual stresses,which can adversely affect the fatigue performance of AM parts.To the best of the authors’knowledge,a comprehensive review does not exist regarding the distortion and residual stresses dedicated for AM,despite some work has explored the interrelationship between the two.The present review is aimed to fill in the identified knowledge gap,by first describing the evolution of distortion and residual stresses for a range of AM processes,and second assessing their influencing factors.This allows us to elucidate their formation mechanisms from both the micro-and macro-scales.Moreover,approaches which have been successfully adopted to mitigate both the distortion and residual stresses are reviewed.It is anticipated that this review paper opens many opportunities to increase the success rate of AM parts by improving the dimension precision and fatigue life.展开更多
Polymerization-induced cooperative assembly(PICA)is reported to efficiently access inverse bicontinuous mesophases within particles consisting of amphiphilic block copolymers(BCPs)and solvophobic copolymers.Reversible...Polymerization-induced cooperative assembly(PICA)is reported to efficiently access inverse bicontinuous mesophases within particles consisting of amphiphilic block copolymers(BCPs)and solvophobic copolymers.Reversible addition-fragmentation chain transfer(RAFT)dispersion alternating copolymerization of styrene and pentafluorostyrene is conducted in 2%v/v toluene/ethanol by simultaneously using poly(N,N-dimethylacrylamide)(PDMA29)as a macromolecular chain transfer agent(macro-CTA)and small molecule CTA.展开更多
A synchronization control scheme is proposed for uncertain coronary artery system (CAS) with input saturation. In order to deal with the input saturation, linear matrix inequalities (LMIS), adequate conditions are obt...A synchronization control scheme is proposed for uncertain coronary artery system (CAS) with input saturation. In order to deal with the input saturation, linear matrix inequalities (LMIS), adequate conditions are obtained based on the local sector condition. Furthermore, by constructing Lyapunov-Krasovskii functional (LKF), we design a state feedback controller to achieve synchronization for chaos system with input saturation. Moreover, the improved Jensen inequality, convex analysis, delay-partitioning approach and Moon et al.’s inequality are utilized to get the less conservative. Finally, the simulation result is given to explain the effectiveness of the proposed synchronization control scheme.展开更多
Biphenyl moiety represents a unique structural motif of many natural and unnatural products with biological interests, and dehydrogenative couplings of two aryl C–H bonds under oxidative conditions is unambiguously t...Biphenyl moiety represents a unique structural motif of many natural and unnatural products with biological interests, and dehydrogenative couplings of two aryl C–H bonds under oxidative conditions is unambiguously the most efficient and direct preparation of these compounds. However, higher oxidation potential of benzene derivatives makes such oxidative couplings much more difficult than other arenes. Only very limited advances have been achieved on direct formation of the crucial C–C bond between two phenyl derivatives by dehydrogenative phenyl coupling in the last two decades. This article briefly summarized and commented a number of representative recent achievements in this attractive field, including homo-, cross-and intramolecular rearrangement and couplings, as well as their applications in organic synthesis.展开更多
ABSTRACT:Lithium–sulfur(Li–S)batteries are regarded as highly promising next-generation energy storage technologies due to their high theoretical specific energy(2600 Wh·kg^(−1)),low cost,and the abundance of s...ABSTRACT:Lithium–sulfur(Li–S)batteries are regarded as highly promising next-generation energy storage technologies due to their high theoretical specific energy(2600 Wh·kg^(−1)),low cost,and the abundance of sulfur.However,their practical application is severely hindered by the shuttle effect of soluble lithium polysulfides(LiPSs)and sluggish sulfur redox kinetics,leading to rapid capacity degradation.The inherent electronic structure of CoSe_(2),employed as a catalyst,restricts its catalytic efficiency.This work proposed a synergistic strategy combining nickel doping and heterointerface engineering to modulate the electronic structure of CoSe_(2) and enhance bidirectional sulfur electrochemistry.Combined structural characterization and density functional theory(DFT)calculations demonstrated that Ni doping induced lattice distortion in CoSe_(2),forming shortened Ni–Se bonds.This prompted a shift of the Co 3d band towards the Fermi level,thereby significantly enhancing the intrinsic conductivity of the material.Concurrently,lattice defects enhanced the availability of active sites for Li_(2)S nucleation.Augmented by the dual physical/chemical confinement of LiPSs provided by the N-doped carbon skeleton,this design established an“adsorption-catalysis”synergistic mechanism,effectively suppressing the shuttle effect and accelerating conversion kinetics.The fabricated Ni-CoSe_(2)/nitrogen-doped carbon(NC)-based Li–S battery delivered a high initial specific capacity of 1219 mAh·g^(−1) at 0.1 C and maintained an ultralow capacity decay rate of 0.064%per cycle over 1000 cycles at 1 C.Notably,the battery also exhibited exceptional cycling stability under lean electrolyte and high sulfur loading conditions.This study elucidated the enhancement mechanism through electronic structure modulation via integrated experimental and theoretical approaches,providing a novel design concept for advanced energy storage materials.展开更多
基金funded by the Scientific Research Project of China Academy of Railway Sciences Group Co.,Ltd(No.2024YJ332 and No.2024QT005)Scientific Research Special Project of China State Railway Group Co.,Ltd(No.TICSTR-2024-Ⅳ-007).
文摘Purpose–This study solves the key problem that the static level monitoring is susceptible to temperature interference and affects the accuracy in slope instability/deformation monitoring.The purpose is to develop a reliable temperature compensation method for the system,improve the accuracy of slope stability monitoring and provide support for improving the safety and safety monitoring of engineering spoil slope and other projects.Design/methodology/approach–Combined with theoretical analysis and experimental verification,the temperature compensation method is explored.The working principle of the hydrostatic leveling monitoring system is analyzed and the data processing formula,the temperature error calculation formula and the calculation formula for eliminating the error settlement value are derived.The temperature compensation method is established and verified by the field test of the engineering spoil slope which is disturbed by a debris flow.Findings–The experimental results show that this method can reduce the error of the static level monitoring system by about 40%.The field test shows that the fluctuation of slope settlement monitoring value is reduced after temperature compensation and the monitoring value is consistent with the actual situation,which has certain practicability.Originality/value–The originality of this study is to derive a theoretical formula for quantifying/eliminating temperature errors in static leveling and to establish a practical temperature compensation method.The accuracy of the system is improved,which provides a reference for slope stability monitoring under complex environment(especially railway geotechnical engineering)and promotes the development of precision monitoring technology.
基金National Natural Science Foundation of China (Nos. 52488201, 52076177, and 52476222)China National Key Research and Development Plan Project (No. 2021YFF0500503)+1 种基金Key Research and Development Program of Shaanxi (No. 2024GH-YBXM-02)China Fundamental Research Funds for the Central Universities。
文摘Combining water electrolysis and rechargeable battery technologies into a single system holds great promise for the co-production of hydrogen (H_(2)) and electricity.However,the design and development of such systems is still in its infancy.Herein,an integrated hydrogen-oxygen (O_(2))-electricity co-production system featuring a bipolar membrane-assisted decoupled electrolyzer and a Na-Zn ion battery was established with sodium nickelhexacyanoferrate (NaNiHCF) and Zn^(2+)/Zn as dual redox electrodes.The decoupled electrolyzer enables to produce H_(2)and O_(2)in different time and space with almost 100%Faradaic efficiency at 100 mA cm^(-2).Then,the charged NaNiHCF and Zn electrodes after the electrolysis processes formed a Na-Zn ion battery,which can generate electricity with an average cell voltage of 1.75 V at 10 m A cm^(-2).By connecting Si photovoltaics with the modular electrochemical device,a well-matched solar driven system was built to convert the intermittent solar energy into hydrogen and electric energy with a solar to hydrogen-electricity efficiency of 16.7%,demonstrating the flexible storage and conversion of renewables.
文摘Purpose–This study is dedicated to systematically collating the distribution and utilization circumstances of geothermal resources in China.Moreover,it endeavors to formulate a comprehensive utilization scheme for geothermal resources during the construction and operation phases of the railway,thereby furnishing robust support and valuable reference for the holistic utilization of geothermal resources along the railway corridor.Design/methodology/approach–Through an in-depth analysis of the extant utilization of geothermal resources in China,it is discerned that the current utilization modalities are relatively rudimentary,bereft of rational planning and characterized by a low utilization rate.Concurrently,by integrating the practical requisites of railway construction and operation and conducting theoretical dissections,a comprehensive utilization plan for the construction and operation periods of railway is proffered.Findings–In light of the railway’s construction and operation characteristics,geothermal utilization models are categorized.During construction,comprehensive modalities include tunnel illumination power generation,construction area heating,tunnel antifreeze using shallow geothermal energy,tunnel pavement antifreeze and construction concrete maintenance.During operation,they comprise operation tunnel antifreeze,railway roadbed antifreeze,railway switch snow melting and deicing,geothermal power station establishment and railway hot spring health tourism planning.Originality/value–According to the characteristics and actual needs of railway construction and operation,it is of great significance to rationally utilize geothermal resources to promote the construction and operation of green railways.
文摘Dear editor,Transcatheter aortic valve replacement (TAVR) is a safe and effective treatment for severe aortic valve stenosis and aortic regurgitation. Multiple randomized trials have proved its therapeutic advantages in patients at any level of surgical risks.
基金supported by the Yalong River Joint Funds of the National Natural Science Foundation of China(No.U1965207)the National Natural Science Foundation of China(Nos.51839007,51779169,and 52009090)。
文摘Accurate prediction of drilling efficiency is critical for developing the earth-rock excavation schedule.The single machine learning(ML)prediction models usually suffer from problems including parameter sensitivity and overfitting.In addition,the influence of environmental and operational factors is often ignored.In response,a novel stacking-based ensemble learning method taking into account the combined effects of those factors is proposed.Through multiple comparison tests,four models,e Xtreme gradient boosting(XGBoost),random forest(RF),back propagation neural network(BPNN)as the base learners,and support vector regression(SVR)as the meta-learner,are selected for stacking.Furthermore,an improved cuckoo search optimization(ICSO)algorithm is developed for hyper-parameter optimization of the ensemble model.The application to a real-world project demonstrates that the proposed method outperforms the popular single ML method XGBoost and the ensemble model optimized by particle swarm optimization(PSO),with 16.43%and 4.88%improvements of mean absolute percentage error(MAPE),respectively.
基金supported by the Science and Technology Support Program of Jiangsu (Nos. BE2014009-1 and BE2014009-2)the Key Research and Development Program of Jiangsu (No. BE2015161)
文摘To investigate the influence of island scanning on the microstructures and mechanical properties of direct laser-deposited Ti–6 Al–4 V structures,two samples are prepared using island scanning and orthogonal successive scanning,respectively.The microstructures,relative density,and mechanical properties of the samples prepared using these two scanning strategies are compared.Each sample exhibits columnarβ-grain morphology and basket-weave microstructure characterization.The grains of the sample prepared using island scanning are significantly finer than that prepared by orthogonal successive scanning due to faster cooling during deposition.However,the relative density of the sample prepared using island scanning was slightly smaller due to the concentration of lack-of-fusion pores at the overlap zone of the island.Tensile testing at room temperature indicates that the ultimate tensile strength and yield strength of the sample prepared using island scanning is enhanced due to finer grains,while the ductility of the sample is weakened due to defects.
基金supported by the National Natural Science Foun-dation of China(22025204,92034301,21773156,and 51932005)the Shanghai Sci.&Tech.and Edu.Committee(19070502700)the Innovation Program of the Shanghai Municipal Education Com-mission(2021-01-07-00-02-E00119).
文摘Simple encapsulation of 3 nm gold nanoparticles in ordered mesoporous carbon with large pores of 17 nm and thick pore walls of 16 nm was achieved by a metal–ligand coordination assisted-selfassembly approach.Polystyrene-block-polyethylene-oxide(PS-b-PEO)diblock copolymer with a large molecular weight of the PS chain and mercaptopropyltrimethoxysilane were used as the template and the metal ligand,respectively.Small-angle X-ray scattering,X-ray diffraction,transmission electron microscopy,and X-ray photoelectron spectroscopy showed that monodispersed aggregation-free gold nanoparticles approximately 3 nm in size were partially embedded in the large open pore structure of the ordered mesoporous carbon.The strong coordination between the gold species and the mercapto groups and the thick porous walls increased the dispersion of the gold nanoparticles and essentially inhibited particle aggregation at 600℃.The gold nanoparticles in the ordered mesoporous carbon are active and stable in the reduction of nitroarenes involving bulky molecules using sodium borohydride as a reducing agent under ambient conditions(30℃)in water.The large interconnected pore structure facilitates the mass transfer of bulky molecules.
基金supported by National Natural Science Foundation of China(Nos.22202065 and 22409159)Natural Science Foundation of Hubei Province of China(No.2024AFB1004)+1 种基金Natural Science Basic Research Program of Shaanxi(Nos.2024JC-YBQN-0119 and 2023SYJ04)the financial support from CHN Energy Zhejiang Ninghai Power Generation CO.Ltd.(No.GJNY-23-122).
文摘Electrocatalytic CO_(2) reduction reaction(CRR)is considered as a sustainable approach to converting CO_(2) into high value-added chemicals,assisting the goal of carbon peaking and carbon neutrality.Electrochemical CRR can be easily regulated by controlling the electrocatalyst,electrolyte,and reactor to produce various chemicals.Among different products,multi-carbon(C_(2+))products draw widespread attention for their high energy density and value along with complex reaction mechanisms.It is well recognized that*CO intermediate plays vital role in forming C_(2+)products and Cu is the only metal catalyst which can efficiently electro-reduce CO_(2) to C_(2+)products.Therefore,researchers developed many strategies to increase the amount of*CO intermediate and further enhance the performance of C_(2+)products.Recently,designing tandem electrocatalysts consisted of Cu and the materials which can convert CO_(2) to*CO intermediate has become a hotspot and achieved great achievements.In this review,we will summary the recent progress in tandem electrocatalysts for CO_(2) reduction to prepare C_(2+)products,including the origin and fundamental mechanism of tandem electrocatalysis,the strategies of catalyst design,and regulation principles.In addition,some newest findings,like Cu tandem catalysts can achieve to produce C_(2+)products,are well introduced.Finally,the remaining challenges and prospects for future development are also proposed.
基金National Key Research and Development Program of China(Grant No.2018YFB1105400)National Natural Science Foundation of China(Grant No.51475238)+2 种基金Key Research and Development Program of Jiangsu Provincial Department of Science and Technology of China(Grant No.BE2019002)China Post-Doctoral Fund(Grant No.2020M671475)UK's Engineering and Physical Sciences Research Council,and EPSRC Early Career Fellowship Scheme[EP/R043973/1].
文摘Additive manufacturing(AM)has gained extensive attention and tremendous research due to its advantages of fabricating complex-shaped parts without the need of casting mold.However,distortion is a known issue for many AM technologies,which decreases the precision of as-built parts.Like fusion welding,the local high-energy input generates residual stresses,which can adversely affect the fatigue performance of AM parts.To the best of the authors’knowledge,a comprehensive review does not exist regarding the distortion and residual stresses dedicated for AM,despite some work has explored the interrelationship between the two.The present review is aimed to fill in the identified knowledge gap,by first describing the evolution of distortion and residual stresses for a range of AM processes,and second assessing their influencing factors.This allows us to elucidate their formation mechanisms from both the micro-and macro-scales.Moreover,approaches which have been successfully adopted to mitigate both the distortion and residual stresses are reviewed.It is anticipated that this review paper opens many opportunities to increase the success rate of AM parts by improving the dimension precision and fatigue life.
基金support by the National Natural Science Foundation of China(nos.51733003 and 21674059)the Fundamental Research Funds for the Central Universities are thanked.
文摘Polymerization-induced cooperative assembly(PICA)is reported to efficiently access inverse bicontinuous mesophases within particles consisting of amphiphilic block copolymers(BCPs)and solvophobic copolymers.Reversible addition-fragmentation chain transfer(RAFT)dispersion alternating copolymerization of styrene and pentafluorostyrene is conducted in 2%v/v toluene/ethanol by simultaneously using poly(N,N-dimethylacrylamide)(PDMA29)as a macromolecular chain transfer agent(macro-CTA)and small molecule CTA.
基金the Technology Commission of Tianjin Municipality (Grants Nos. 18JCYBJC88100 and 15JCYBJC16100)the National Natural Science Foundation of China (Grant No. 61503280).
文摘A synchronization control scheme is proposed for uncertain coronary artery system (CAS) with input saturation. In order to deal with the input saturation, linear matrix inequalities (LMIS), adequate conditions are obtained based on the local sector condition. Furthermore, by constructing Lyapunov-Krasovskii functional (LKF), we design a state feedback controller to achieve synchronization for chaos system with input saturation. Moreover, the improved Jensen inequality, convex analysis, delay-partitioning approach and Moon et al.’s inequality are utilized to get the less conservative. Finally, the simulation result is given to explain the effectiveness of the proposed synchronization control scheme.
基金supported by the National Natural Science Foundation of China(21472087)
文摘Biphenyl moiety represents a unique structural motif of many natural and unnatural products with biological interests, and dehydrogenative couplings of two aryl C–H bonds under oxidative conditions is unambiguously the most efficient and direct preparation of these compounds. However, higher oxidation potential of benzene derivatives makes such oxidative couplings much more difficult than other arenes. Only very limited advances have been achieved on direct formation of the crucial C–C bond between two phenyl derivatives by dehydrogenative phenyl coupling in the last two decades. This article briefly summarized and commented a number of representative recent achievements in this attractive field, including homo-, cross-and intramolecular rearrangement and couplings, as well as their applications in organic synthesis.
基金supported in part by the National Natural Science Foundation of China(No.52303303)Henan Province Science and Technology Research and Development Joint Fund(Nos.235200810047 and 235200810003)+1 种基金Central Plains Academician Fund Project(No.231723008)the Scientific Research Foundation of Henan Academy of Sciences(No.241823159)。
文摘ABSTRACT:Lithium–sulfur(Li–S)batteries are regarded as highly promising next-generation energy storage technologies due to their high theoretical specific energy(2600 Wh·kg^(−1)),low cost,and the abundance of sulfur.However,their practical application is severely hindered by the shuttle effect of soluble lithium polysulfides(LiPSs)and sluggish sulfur redox kinetics,leading to rapid capacity degradation.The inherent electronic structure of CoSe_(2),employed as a catalyst,restricts its catalytic efficiency.This work proposed a synergistic strategy combining nickel doping and heterointerface engineering to modulate the electronic structure of CoSe_(2) and enhance bidirectional sulfur electrochemistry.Combined structural characterization and density functional theory(DFT)calculations demonstrated that Ni doping induced lattice distortion in CoSe_(2),forming shortened Ni–Se bonds.This prompted a shift of the Co 3d band towards the Fermi level,thereby significantly enhancing the intrinsic conductivity of the material.Concurrently,lattice defects enhanced the availability of active sites for Li_(2)S nucleation.Augmented by the dual physical/chemical confinement of LiPSs provided by the N-doped carbon skeleton,this design established an“adsorption-catalysis”synergistic mechanism,effectively suppressing the shuttle effect and accelerating conversion kinetics.The fabricated Ni-CoSe_(2)/nitrogen-doped carbon(NC)-based Li–S battery delivered a high initial specific capacity of 1219 mAh·g^(−1) at 0.1 C and maintained an ultralow capacity decay rate of 0.064%per cycle over 1000 cycles at 1 C.Notably,the battery also exhibited exceptional cycling stability under lean electrolyte and high sulfur loading conditions.This study elucidated the enhancement mechanism through electronic structure modulation via integrated experimental and theoretical approaches,providing a novel design concept for advanced energy storage materials.
