A comparative analytical study of several control strategies for semi-active(SA) devices installed in baseisolated buildings aiming to reduce earthquake induced vibrations is presented.Three force tracking schemes com...A comparative analytical study of several control strategies for semi-active(SA) devices installed in baseisolated buildings aiming to reduce earthquake induced vibrations is presented.Three force tracking schemes comprising a linear controller plus a 'clipped' algorithm and a nonlinear output feedback controller(NOFC) are considered to tackle this problem.Linear controllers include the integral controller(I),the linear quadratic regulator(LQR) and the model predictive controller(MPC).A single degree-of-freedom system subjected to input accelerograms representative of the Portuguese seismic actions are first used to validate and evaluate the feasibility of these strategies.The obtained results show that structural systems using SA devices can in general outperform those equipped with passive devices for lower fundamental frequency structural systems,namely base-isolated buildings.The effectiveness of the proposed strategies is also evaluated on a 10 storey base-isolated dual frame-wall building.The force tracking scheme with an integral controller outperforms the other three as well as the original structure and the structure equipped with passive devices.展开更多
Although pre-Northridge earthquake steel moment resisting frame buildings have been shown to be susceptible to brittle connection failures,they still represent a large fraction of the existing steel buildings in the U...Although pre-Northridge earthquake steel moment resisting frame buildings have been shown to be susceptible to brittle connection failures,they still represent a large fraction of the existing steel buildings in the United States of America.In this study,the performance of the 3-and 9-story Los Angeles pre-Northridge SAC buildings are analyzed considering ductile and brittle beam-column connection failures,and their uncertainty.This paper contributes to understanding the influence of uncertainty associated with connections brittle fracture on building interstory deformation capacity and its impact on bias and variability of fragility functions and loss assessment.The results show that considering brittle connections leads to significantly l arger d rift demands a nd t o h igher r epair costs,particularly under intense ground shaking.New fragility curve parameters are derived that account for the effect of the uncertainty of the strength and deformation capacity of brittle connections.展开更多
This paper presents research on transport properties and alkali-silica reaction (ASR) susceptibility of mortars containing a pozzolanic waste generated in the fluid catalytic cracking (wFCC) unit by the Portuguese oil...This paper presents research on transport properties and alkali-silica reaction (ASR) susceptibility of mortars containing a pozzolanic waste generated in the fluid catalytic cracking (wFCC) unit by the Portuguese oil-refinery. For this purpose, two series of mortars were prepared by partially replacing cement with 5%, 10% and 15% of wFCC catalyst. The main difference between the two series of mortars is the sand reactivity used in their composition. The results revealed that wFCC catalyst blended cement mortars exhibit an increased resistance against capillary water absorption and chloride migration, as well as a considerable inhibition effect on deleterious ASR expansion. However, under the adopted experimental conditions the incorporation of wFCC catalyst in mortars decreases their carbonation resistance.展开更多
The management of information systems contributes to the economic development of the construction sector by organizing and structuring technical and economic information. It is proposed how BIM (Building Information M...The management of information systems contributes to the economic development of the construction sector by organizing and structuring technical and economic information. It is proposed how BIM (Building Information Modelling) and a Portuguese information system-ProNIC (abbreviation for Protocol for the Standardization of Construction Technical Information) may be interconnected. The scope of this information transmission in construction sector is a step to solve several problems that have been identified in conception of BIM models.展开更多
Building Information Modeling (BIM) is a process involving generation and management of digital representations of physical and functional characteristics of places, which can be exchanged or networked to support deci...Building Information Modeling (BIM) is a process involving generation and management of digital representations of physical and functional characteristics of places, which can be exchanged or networked to support decision-making in architecture, engineering and construction (AEC) sector. BIM is a relatively new technology in an industry typically slow to adopt changes, especially in Portugal. The present paper aims to frame the international implementation of BIM in order to propose a roadmap to spread the use of BIM methodologies in Portugal in the next decade.展开更多
对由大坝、坝基、水库和大坝下游区域组成的系统,应从结构、水力、运行和环境等方面评价其系统安全性。尤其是对已建大坝的结构安全评价应以建立主荷载、结构性能和结构响应之间的相关性为基础。将观测到的响应值与基于结构性态模型或...对由大坝、坝基、水库和大坝下游区域组成的系统,应从结构、水力、运行和环境等方面评价其系统安全性。尤其是对已建大坝的结构安全评价应以建立主荷载、结构性能和结构响应之间的相关性为基础。将观测到的响应值与基于结构性态模型或历史观测数据得到的预测值进行比较。多年来,技术设备方面的新进展即自动数据采集系统的采用不断被引入这一领域。伴随信息系统技术的重要发展,这一变化面临着新的挑战,但同时也提供了新的机遇,如数据管理系统的开发,可使大坝安全管理人员尽快访问数据、解读信息并做出决策。葡萄牙国家土木工程实验室(National Laboratory for Civil Engineering,LNEC)开发了GestBarragens系统,该系统采用模块化方法设计和开发,基于Web界面访问公共数据架构。笔者旨在介绍GestBarragens系统如何优化针对100余座大型混凝土坝和土石坝开展的大坝安全控制相关的活动,包括通过监测系统对某些物理量进行观测、信息的解读和向负责大坝安全的实体组织传达预警信息。由于GestBarragens系统的开发是一个不断演进的过程,笔者还将讨论未来的开发。展开更多
Single-atom catalysts based on graphitic carbon nitride(g-C_(3)N_(4))show high potential for hydrogen production photocatalytically.However,it is still a challenge to develop single-atom-based g-C_(3)N_(4)due to the c...Single-atom catalysts based on graphitic carbon nitride(g-C_(3)N_(4))show high potential for hydrogen production photocatalytically.However,it is still a challenge to develop single-atom-based g-C_(3)N_(4)due to the complex synthesis procedures,limited active sites,and insufficient mechanistic understanding.Herein,a facile oxygen-tolerant synthesis strategy was developed,which utilizes the nitrogen-rich structure of g-C_(3)N_(4)to capture Fe single atoms from ammonium iron citrate,successfully constructing an efficient photocatalytic composite.The resulting Fe single-atom-modified g-C_(3)N_(4)catalyst exhibited highly improved light absorption,charge carrier separation,and a substantially enhanced rate of H_(2)production photocatalytically under visible light irradiation.Experimental results demonstrated that the optimal sample achieves a H_(2)production rate of 683μmol·h-1·g^(-1),representing a 425% enhancement compared to pristine g-C_(3)N_(4).This study presents a facile oxygen-tolerant approach for metal immobilization using metal-organic precursors,where the nitrogen-rich framework of g-C_(3)N_(4)effectively captures Fe atoms as singular site within the composite.The developed synthesis strategy provides new insights for designing high-performance single-atom photocatalytic materials,potentially advancing the application and development of photocatalysis.展开更多
This paper presents an extensive experimental investigation campaign concerning the thermal fire reaction of firebrands,as they accumulate on the exterior walls of dwellings,a common occurrence in southern Europe.Thre...This paper presents an extensive experimental investigation campaign concerning the thermal fire reaction of firebrands,as they accumulate on the exterior walls of dwellings,a common occurrence in southern Europe.Three types of wall core layers were studied:bricks,designed according to the Exterior Thermal Insulation Composite Systems(ETICS)methodology,cross-laminated timber(CLT)and normal wood(NW),both utilizing the sandwich methodology.The wall specimens are made of a combination of materials such as three types of mortar(Tria,Sika,and Weber),and various thermal insulation materials,such as agglomerates of composite cork,impermeable membranes,rigid rock wool,fireproof paint,and extruded polystyrene rigid foam(XPS),which are recommended for their good performance against fire and high temperatures.Firebrands are then deposited on the localized surfaces of the wall specimens,and the temperature is recorded in each layer.This study aims to precisely verify the firebrand reaction to fire,including the type of ignition,smoke and droplet production.The insulation capabilities of each insulation and wall system will also be analyzed.展开更多
Broadband optoelectronic devices intrigue enormous interests on account of their promising potential in optical communications,sensors and environmental monitoring.PbSe nanocrystals are promising candidates for the co...Broadband optoelectronic devices intrigue enormous interests on account of their promising potential in optical communications,sensors and environmental monitoring.PbSe nanocrystals are promising candidates for the construction of next-generation photodetectors due to their fascinating intrinsic properties and solution-processed compatibility with varied substrates.Here,we report the fabrication of a broadband photodetector on the basis of high-quality solution-processed PbSe nanorods in rock-salt phase grown along unconventionally anisotropic growth direction of<112>zone axis.The rock-salt PbSe nanorods are synthesized in solution phase over the catalysis of Ag2Se with relatively high-temperature body-centered cubic phase via a solution-solid-solid growth regime using oleylamine and oleic acid as solvents and stabilizer surfactants,from which the PbSe nanorods with the unconventionally anisotropic growth direction are controllably grown in size and shape in the synthetic procedure typically with about 17 nm in diameter and 58 nm in length on average.Meanwhile,the PbSe nanorods-based photodetector exhibits a broadband response from 405 to 1,064 nm with a high responsivity of 0.78 A·W^(-1)and a fast response time of 17.5μs.The response time is much faster in comparison with most of the PbSe-based photodetectors with response time in millisecond level.展开更多
The incorporation of pro-osteogenic growth factors into bone graft materials to enhance bone regeneration is a key research area within the field of bone tissue engineering and regenerative medicine.However,growth fac...The incorporation of pro-osteogenic growth factors into bone graft materials to enhance bone regeneration is a key research area within the field of bone tissue engineering and regenerative medicine.However,growth factors directly incorporated in protein form are easily degraded,and have a limited active half-life,which cannot exert long-term and stable osteoinductive and oteoconductive effects.The combination of gene therapy and tissue engineering through gene-activated matrix(GAM)may provide a good alternative solution to overcome such limitations.Scaffold materials can be combined together with plasmid DNA and a chemical-based transfection agent to form GAM,through which transfected cells could secrete growth factors in a sustained manner over a longer time duration;thereby enabling bone graft materials to act as a repository of therapeutic genes,while providing structural support and a scaffold matrix for new bone tissue ingrowth.In this study,we prepared hydroxyapatite/chitosan-microspheres(HA/CS-MS)with microfabrication technology and emulsification method,and loaded the polyethylene imine/bone morphogenetic protein 2 plasmid(PEI/pBMP2)complexes with high transfection capacity(transfection efficiency up to 54.79%±4.95%),thus forming a novel GAM system with superior bone regeneration capacity—PEI/pBMP2-HA/CS-MS.The in vitro experiments in this study demonstrated that our GAM had excellent biocompatibility(with cell viability over 95%),and that the as-fabricated microsphere material possessed a nano-network fibrous structure similar to natural extracellular matrix(ECM),together with a higher surface area that can provide more cell adhesion sites.The sizes of the prepared microspheres were mainly distributed in the 160–180μm range,while the maximal loading rate of PEI-pBMP2 complexes was 59.79%±1.85%.As a loaded complexes system,the GAM can release plasmids in a slow controlled manner,effectively transfecting surrounding target cells(release effect for up to 21 days),while cells adherent to the material can also take up plasmids,resulting in sustained secretion of the target protein,thereby effectively promoting bone regeneration.In vivo data from micro-computed tomography(micro-CT)and histological staining showed that the use of the composite materials effectively enhanced bone regeneration in defect areas.These findings thus demonstrated that the novel GAM system had excellent osteoinductivity with significant clinical potential.展开更多
Gallium antimonide(GaSb)-based nanostructures have been reported via various vapor-phase synthetic routes while there is not a report on the growth of GaSb nanostructures via a complete one-step solution-phase synthet...Gallium antimonide(GaSb)-based nanostructures have been reported via various vapor-phase synthetic routes while there is not a report on the growth of GaSb nanostructures via a complete one-step solution-phase synthetic strategy.Herein we report the design and synthesis of tadpole-like Ga/GaSb nanostructures by a one-step solution-phase synthetic route typically from the precursors of commercial triphenyl antimony(Sb(Ph)_(3))and trimethylaminogallium(Ga(NMe_(2))_(3))at 260°C in 1-octadecene.The GaSb nanocrystals are grown based on a solution–liquid–solid(SLS)mechanism with zinc blende phase,and their size and shape can be controlled in the procedures via manipulating the reaction conditions.Meanwhile,the tadpole-like Ga/GaSb nanostructures can be applied for the fabrication of a GaSb/Si nanostructured heterojunction-like photodetector over silicon wafer,which demonstrates excellent photoresponse and detection performances from wavelength of 405 to 1,064 nm with high photoresponding rate.Typically,the photodetector exhibits a high responsivity of 18.9 A·W^(−1),a superior detectivity of 1.1×10^(13)Jones,and an ultrafast response speed of 44 ns.The present work provides a new strategy to group III–V antimonide-based semiconducting nanostructures that are capable for the fabrication of photodetector with broadband,high-detectivity,and high-speed photodetecting performances.展开更多
Nano Research volume 13,pages1704–1712(2020)Cite this article 191 Accesses Metrics details Abstract Intelligent gas sensors based on the layered transition metal dichalcogenides(TMDs)have attracted great interest in ...Nano Research volume 13,pages1704–1712(2020)Cite this article 191 Accesses Metrics details Abstract Intelligent gas sensors based on the layered transition metal dichalcogenides(TMDs)have attracted great interest in the field of gas sensing due to their multiple active sites,fast electron,mass transfer capability and large surface-to-volume ratio.However,conventional TMDs-based sensors typically work at elevated temperature in inert atmosphere,which would largely limit the corresponding practical applications.Herein,novel oxygen-doped MoSe2 hierarchical nanostructures composed of ultrathin nanosheets with large specific surface area have been designed and generated typically at 200°C in air for fast and facile gas sensing of trimethylamine(TMA),effectively.Benefited from the gas-accessible hierarchical morphology and high surface area with abundant nanochannels,highly sensitive and selective detection of trace TMA has been achieved under ambient condition,and as detected the theoretical limit of detection(LOD)is 8 ppb,which is the lowest for TMA detection under ambient condition among the reported studies.The mechanism of oxygen doping on the improved gas-sensing performance has been investigated,revealing that the oxygen doping could greatly optimize the electronic structure,thus regulate the Fermi level of MoSe2 as well as the affinity between TMA molecule and sensor surface.It is expected that the oxygen doping strategy developed for the highly efficient gas sensors based on TMDs in present work may also be applicable to other types of gas-sensing semiconductors,which could open up a new direction for the rational design of high-performance gas sensors working under ambient condition.展开更多
基金The Portuguese Foundation for Science and Technology(FCT)for the Ph D scholarship provided(reference SFRH/BD/84769/2012)
文摘A comparative analytical study of several control strategies for semi-active(SA) devices installed in baseisolated buildings aiming to reduce earthquake induced vibrations is presented.Three force tracking schemes comprising a linear controller plus a 'clipped' algorithm and a nonlinear output feedback controller(NOFC) are considered to tackle this problem.Linear controllers include the integral controller(I),the linear quadratic regulator(LQR) and the model predictive controller(MPC).A single degree-of-freedom system subjected to input accelerograms representative of the Portuguese seismic actions are first used to validate and evaluate the feasibility of these strategies.The obtained results show that structural systems using SA devices can in general outperform those equipped with passive devices for lower fundamental frequency structural systems,namely base-isolated buildings.The effectiveness of the proposed strategies is also evaluated on a 10 storey base-isolated dual frame-wall building.The force tracking scheme with an integral controller outperforms the other three as well as the original structure and the structure equipped with passive devices.
文摘Although pre-Northridge earthquake steel moment resisting frame buildings have been shown to be susceptible to brittle connection failures,they still represent a large fraction of the existing steel buildings in the United States of America.In this study,the performance of the 3-and 9-story Los Angeles pre-Northridge SAC buildings are analyzed considering ductile and brittle beam-column connection failures,and their uncertainty.This paper contributes to understanding the influence of uncertainty associated with connections brittle fracture on building interstory deformation capacity and its impact on bias and variability of fragility functions and loss assessment.The results show that considering brittle connections leads to significantly l arger d rift demands a nd t o h igher r epair costs,particularly under intense ground shaking.New fragility curve parameters are derived that account for the effect of the uncertainty of the strength and deformation capacity of brittle connections.
文摘This paper presents research on transport properties and alkali-silica reaction (ASR) susceptibility of mortars containing a pozzolanic waste generated in the fluid catalytic cracking (wFCC) unit by the Portuguese oil-refinery. For this purpose, two series of mortars were prepared by partially replacing cement with 5%, 10% and 15% of wFCC catalyst. The main difference between the two series of mortars is the sand reactivity used in their composition. The results revealed that wFCC catalyst blended cement mortars exhibit an increased resistance against capillary water absorption and chloride migration, as well as a considerable inhibition effect on deleterious ASR expansion. However, under the adopted experimental conditions the incorporation of wFCC catalyst in mortars decreases their carbonation resistance.
文摘The management of information systems contributes to the economic development of the construction sector by organizing and structuring technical and economic information. It is proposed how BIM (Building Information Modelling) and a Portuguese information system-ProNIC (abbreviation for Protocol for the Standardization of Construction Technical Information) may be interconnected. The scope of this information transmission in construction sector is a step to solve several problems that have been identified in conception of BIM models.
文摘Building Information Modeling (BIM) is a process involving generation and management of digital representations of physical and functional characteristics of places, which can be exchanged or networked to support decision-making in architecture, engineering and construction (AEC) sector. BIM is a relatively new technology in an industry typically slow to adopt changes, especially in Portugal. The present paper aims to frame the international implementation of BIM in order to propose a roadmap to spread the use of BIM methodologies in Portugal in the next decade.
文摘对由大坝、坝基、水库和大坝下游区域组成的系统,应从结构、水力、运行和环境等方面评价其系统安全性。尤其是对已建大坝的结构安全评价应以建立主荷载、结构性能和结构响应之间的相关性为基础。将观测到的响应值与基于结构性态模型或历史观测数据得到的预测值进行比较。多年来,技术设备方面的新进展即自动数据采集系统的采用不断被引入这一领域。伴随信息系统技术的重要发展,这一变化面临着新的挑战,但同时也提供了新的机遇,如数据管理系统的开发,可使大坝安全管理人员尽快访问数据、解读信息并做出决策。葡萄牙国家土木工程实验室(National Laboratory for Civil Engineering,LNEC)开发了GestBarragens系统,该系统采用模块化方法设计和开发,基于Web界面访问公共数据架构。笔者旨在介绍GestBarragens系统如何优化针对100余座大型混凝土坝和土石坝开展的大坝安全控制相关的活动,包括通过监测系统对某些物理量进行观测、信息的解读和向负责大坝安全的实体组织传达预警信息。由于GestBarragens系统的开发是一个不断演进的过程,笔者还将讨论未来的开发。
基金financially supported by the National Natural Science Foundation of China(No.22272159)the Chinese Academy of Sciences(No.KFJ-XCZX-202304).
文摘Single-atom catalysts based on graphitic carbon nitride(g-C_(3)N_(4))show high potential for hydrogen production photocatalytically.However,it is still a challenge to develop single-atom-based g-C_(3)N_(4)due to the complex synthesis procedures,limited active sites,and insufficient mechanistic understanding.Herein,a facile oxygen-tolerant synthesis strategy was developed,which utilizes the nitrogen-rich structure of g-C_(3)N_(4)to capture Fe single atoms from ammonium iron citrate,successfully constructing an efficient photocatalytic composite.The resulting Fe single-atom-modified g-C_(3)N_(4)catalyst exhibited highly improved light absorption,charge carrier separation,and a substantially enhanced rate of H_(2)production photocatalytically under visible light irradiation.Experimental results demonstrated that the optimal sample achieves a H_(2)production rate of 683μmol·h-1·g^(-1),representing a 425% enhancement compared to pristine g-C_(3)N_(4).This study presents a facile oxygen-tolerant approach for metal immobilization using metal-organic precursors,where the nitrogen-rich framework of g-C_(3)N_(4)effectively captures Fe atoms as singular site within the composite.The developed synthesis strategy provides new insights for designing high-performance single-atom photocatalytic materials,potentially advancing the application and development of photocatalysis.
基金the Foundation for Science and Technology(FCT),Portugal,for the Project“New Fireproof Dwellings for Wildfire PTDC/ECI-CON/2240/2020”(DOI:10.54499/PTDC/ECI-CON/2240/2020)the Foundation for Science and Technology's support through funding UIDB/04625/2020 from the research unit CERIS(DOI:10.54499/UIDB/04625/2020)+1 种基金the financing of the doctoral grants SFRH/BD/03935/2023(DOI:10.54499/2023.03935.BD)SFRH/BD/04011/2023(DOI:10.54499/2023.04011.BD).
文摘This paper presents an extensive experimental investigation campaign concerning the thermal fire reaction of firebrands,as they accumulate on the exterior walls of dwellings,a common occurrence in southern Europe.Three types of wall core layers were studied:bricks,designed according to the Exterior Thermal Insulation Composite Systems(ETICS)methodology,cross-laminated timber(CLT)and normal wood(NW),both utilizing the sandwich methodology.The wall specimens are made of a combination of materials such as three types of mortar(Tria,Sika,and Weber),and various thermal insulation materials,such as agglomerates of composite cork,impermeable membranes,rigid rock wool,fireproof paint,and extruded polystyrene rigid foam(XPS),which are recommended for their good performance against fire and high temperatures.Firebrands are then deposited on the localized surfaces of the wall specimens,and the temperature is recorded in each layer.This study aims to precisely verify the firebrand reaction to fire,including the type of ignition,smoke and droplet production.The insulation capabilities of each insulation and wall system will also be analyzed.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.U1932150 and 21571166)Anhui Provincial Natural Science Foundation(No.1908085QB72).
文摘Broadband optoelectronic devices intrigue enormous interests on account of their promising potential in optical communications,sensors and environmental monitoring.PbSe nanocrystals are promising candidates for the construction of next-generation photodetectors due to their fascinating intrinsic properties and solution-processed compatibility with varied substrates.Here,we report the fabrication of a broadband photodetector on the basis of high-quality solution-processed PbSe nanorods in rock-salt phase grown along unconventionally anisotropic growth direction of<112>zone axis.The rock-salt PbSe nanorods are synthesized in solution phase over the catalysis of Ag2Se with relatively high-temperature body-centered cubic phase via a solution-solid-solid growth regime using oleylamine and oleic acid as solvents and stabilizer surfactants,from which the PbSe nanorods with the unconventionally anisotropic growth direction are controllably grown in size and shape in the synthetic procedure typically with about 17 nm in diameter and 58 nm in length on average.Meanwhile,the PbSe nanorods-based photodetector exhibits a broadband response from 405 to 1,064 nm with a high responsivity of 0.78 A·W^(-1)and a fast response time of 17.5μs.The response time is much faster in comparison with most of the PbSe-based photodetectors with response time in millisecond level.
基金supported by the National Natural Science Foundation of China(No.51973004)the Natural Science Foundation of Anhui Province,China(No.1908085MH255).
文摘The incorporation of pro-osteogenic growth factors into bone graft materials to enhance bone regeneration is a key research area within the field of bone tissue engineering and regenerative medicine.However,growth factors directly incorporated in protein form are easily degraded,and have a limited active half-life,which cannot exert long-term and stable osteoinductive and oteoconductive effects.The combination of gene therapy and tissue engineering through gene-activated matrix(GAM)may provide a good alternative solution to overcome such limitations.Scaffold materials can be combined together with plasmid DNA and a chemical-based transfection agent to form GAM,through which transfected cells could secrete growth factors in a sustained manner over a longer time duration;thereby enabling bone graft materials to act as a repository of therapeutic genes,while providing structural support and a scaffold matrix for new bone tissue ingrowth.In this study,we prepared hydroxyapatite/chitosan-microspheres(HA/CS-MS)with microfabrication technology and emulsification method,and loaded the polyethylene imine/bone morphogenetic protein 2 plasmid(PEI/pBMP2)complexes with high transfection capacity(transfection efficiency up to 54.79%±4.95%),thus forming a novel GAM system with superior bone regeneration capacity—PEI/pBMP2-HA/CS-MS.The in vitro experiments in this study demonstrated that our GAM had excellent biocompatibility(with cell viability over 95%),and that the as-fabricated microsphere material possessed a nano-network fibrous structure similar to natural extracellular matrix(ECM),together with a higher surface area that can provide more cell adhesion sites.The sizes of the prepared microspheres were mainly distributed in the 160–180μm range,while the maximal loading rate of PEI-pBMP2 complexes was 59.79%±1.85%.As a loaded complexes system,the GAM can release plasmids in a slow controlled manner,effectively transfecting surrounding target cells(release effect for up to 21 days),while cells adherent to the material can also take up plasmids,resulting in sustained secretion of the target protein,thereby effectively promoting bone regeneration.In vivo data from micro-computed tomography(micro-CT)and histological staining showed that the use of the composite materials effectively enhanced bone regeneration in defect areas.These findings thus demonstrated that the novel GAM system had excellent osteoinductivity with significant clinical potential.
基金supported by the National Natural Science Foundation of China(Nos.U1932150 and 21571166)Anhui Provincial Natural Science Foundation(No.1908085QB72).
文摘Gallium antimonide(GaSb)-based nanostructures have been reported via various vapor-phase synthetic routes while there is not a report on the growth of GaSb nanostructures via a complete one-step solution-phase synthetic strategy.Herein we report the design and synthesis of tadpole-like Ga/GaSb nanostructures by a one-step solution-phase synthetic route typically from the precursors of commercial triphenyl antimony(Sb(Ph)_(3))and trimethylaminogallium(Ga(NMe_(2))_(3))at 260°C in 1-octadecene.The GaSb nanocrystals are grown based on a solution–liquid–solid(SLS)mechanism with zinc blende phase,and their size and shape can be controlled in the procedures via manipulating the reaction conditions.Meanwhile,the tadpole-like Ga/GaSb nanostructures can be applied for the fabrication of a GaSb/Si nanostructured heterojunction-like photodetector over silicon wafer,which demonstrates excellent photoresponse and detection performances from wavelength of 405 to 1,064 nm with high photoresponding rate.Typically,the photodetector exhibits a high responsivity of 18.9 A·W^(−1),a superior detectivity of 1.1×10^(13)Jones,and an ultrafast response speed of 44 ns.The present work provides a new strategy to group III–V antimonide-based semiconducting nanostructures that are capable for the fabrication of photodetector with broadband,high-detectivity,and high-speed photodetecting performances.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.U1932150 and 21571166)Anhui Provincial Natural Science Foundation(No.1908085QB72)the Fundamental Research Funds for the Central Universities(No.WK2060190099).
文摘Nano Research volume 13,pages1704–1712(2020)Cite this article 191 Accesses Metrics details Abstract Intelligent gas sensors based on the layered transition metal dichalcogenides(TMDs)have attracted great interest in the field of gas sensing due to their multiple active sites,fast electron,mass transfer capability and large surface-to-volume ratio.However,conventional TMDs-based sensors typically work at elevated temperature in inert atmosphere,which would largely limit the corresponding practical applications.Herein,novel oxygen-doped MoSe2 hierarchical nanostructures composed of ultrathin nanosheets with large specific surface area have been designed and generated typically at 200°C in air for fast and facile gas sensing of trimethylamine(TMA),effectively.Benefited from the gas-accessible hierarchical morphology and high surface area with abundant nanochannels,highly sensitive and selective detection of trace TMA has been achieved under ambient condition,and as detected the theoretical limit of detection(LOD)is 8 ppb,which is the lowest for TMA detection under ambient condition among the reported studies.The mechanism of oxygen doping on the improved gas-sensing performance has been investigated,revealing that the oxygen doping could greatly optimize the electronic structure,thus regulate the Fermi level of MoSe2 as well as the affinity between TMA molecule and sensor surface.It is expected that the oxygen doping strategy developed for the highly efficient gas sensors based on TMDs in present work may also be applicable to other types of gas-sensing semiconductors,which could open up a new direction for the rational design of high-performance gas sensors working under ambient condition.
