As a product of the deep integration of financial technology and the digital economy,digital finance plays a significant role in promoting the development of new quality productivity.This paper first elaborates on the...As a product of the deep integration of financial technology and the digital economy,digital finance plays a significant role in promoting the development of new quality productivity.This paper first elaborates on the connotations of new quality productivity and digital finance and analyzes the mechanisms by which digital finance promotes the development of new quality productivity from both theoretical and practical perspectives.The aim is to explore the value digital finance brings to the development of new quality productivity,along with the challenges it faces,in order to propose corresponding policy recommendations.展开更多
A pre-ohmic micro-patterned recess process,is utilized to fabricate Ti/Al/Ti/TiN ohmic contact to an ultrathin-barrier(UTB)AlGaN/GaN heterostructure,featuring a significantly reduced ohmic contact resistivity of 0.56...A pre-ohmic micro-patterned recess process,is utilized to fabricate Ti/Al/Ti/TiN ohmic contact to an ultrathin-barrier(UTB)AlGaN/GaN heterostructure,featuring a significantly reduced ohmic contact resistivity of 0.56Ω·mm at an alloy temperature of 550℃.The sheet resistances increase with the temperature following a power law with the index of +2.58,while the specific contact resistivity decreases with the temperature.The contact mechanism can be well described by thermionic field emission(TFE).The extracted Schottky barrier height and electron concentration are 0.31 eV and 5.52×10^(18) cm^(−3),which suggests an intimate contact between ohmic metal and the UTB-AlGaN as well as GaN buffer.A good correlation between ohmic transfer length and the micro-pattern size is revealed,though in-depth investigation is needed.A preliminary CMOS-process-compatible metal-insulator-semiconductor high-mobility transistor(MIS-HEMT)was fabricated with the proposed Au-free ohmic contact technique.展开更多
In this paper,137“First-class universities”and“First-class discipline”construction universities in China are selected as the objects of investigation to analyzes the present situation and characteristics of the g...In this paper,137“First-class universities”and“First-class discipline”construction universities in China are selected as the objects of investigation to analyzes the present situation and characteristics of the game design of University Library in China.Taking the university library in other countries as the reference object,this paper compares the differences of the game design of University Library in China and other countries,sums up the deficiency of the gamification service practice in Chinese university libraries.At last,this paper proposes an optimization path of the gamification design of Chinese University Library from six aspects of game type,game service object,game interactive mode,game application,game development and game playability.展开更多
Eutrophication in coastal area has become more and more serious and mariculture potential is a main cause.Although there are some quantitative research on nutrient loads in national and global perspective,the calculat...Eutrophication in coastal area has become more and more serious and mariculture potential is a main cause.Although there are some quantitative research on nutrient loads in national and global perspective,the calculation method problems make the results controversial.In this paper,the farming activities are divided into fed culture types(include cage culture and pond culture)and extractive culture types(e.g.seaweed,filter-feeding shellfish culture).Based on the annual yield of China in 2019 and feed coefficient of fed culture types and carbon(C),nitrogen(N),and phosphorus(P)content of extractive culture types,the annual nutrient loads was estimated.The results showed that to coastal region of China(1)annual nutrient released by fed culture types were about58451 t of N,9081 t of P,and annual nutrient removed by harvest of extractive culture types were 109245 t of N,11980 t of P and 1.86×10^(6)t of C.Overall,the net amount of nutrient removed annually by mariculture industry were 50794 t of N and 2901 t of P.(2)The nutrient released from mariculture industry influenced nutrient stoichiometry.Pond farming and seaweed farming had the potential of increasing the molar concentration ratio of N and P(N:P),while cage farming and bivalve farming decreased the N:P.(3)Due to different mariculture types and layouts in the coastal regions in China,N and P loading were regional different.Among the coastal regions in China,net release of nutrient from mariculture occurred only in Hainan and Guangxi regions,while in the other regions,N and P were completely removed by harvest.We suggest decrease the amount of fed culture types and increase the amount of integrated culture with extractive culture types.This study will help to adjust mariculture structure and layout at the national level to reduce the environmental impact.展开更多
Background Major infectious disease has become a serious threat to people’s health worldwide.As the world’s largest healthcare workforce and the core forces fighting against the epidemic,nurses are on the frontline ...Background Major infectious disease has become a serious threat to people’s health worldwide.As the world’s largest healthcare workforce and the core forces fighting against the epidemic,nurses are on the frontline of this battle.A number of ethical issues have given rise to numerous concerns that have largely affected nurses in different ways as they respond to the epidemic.In addition,excessive expectations from people can exert undue pressure,which can easily lead to burnout in nurses.Methods In this consensus,the expert panel method was used to develop and reach a consensus.The members involved in the formation of the consensus included an expert discussion panel and a consensus writing expert group,a methodologist,and four secretaries.After 16 rounds of online expert consultation and two rounds of expert panel meetings,the writing team analyzed and reviewed the 78 amendments suggested by the experts to develop a consensus on nursing ethics for prevention and control of major infectious disease outbreaks based on the ethical vision of life care.Results This expert consensus focuses on five essential domains:the responsibilities and rights of nurses,the nurse-patient relationship,the doctor-nurse relationship,and the relationship between society and nurses throughout the epidemic.Conclusions We hope this consensus can help nurses better understand and respond to the ethical issues and challenges in public health emergencies,and raise reasonable public expectations of the roles and responsibilities of nurses in these situations.展开更多
The goal of steganalysis is to detect whether the cover carries the secret information which is embedded by steganographic algorithms.The traditional ste-ganalysis detector is trained on the stego images created by a ...The goal of steganalysis is to detect whether the cover carries the secret information which is embedded by steganographic algorithms.The traditional ste-ganalysis detector is trained on the stego images created by a certain type of ste-ganographic algorithm,whose detection performance drops rapidly when it is applied to detect another type of steganographic algorithm.This phenomenon is called as steganographic algorithm mismatch in steganalysis.To resolve this pro-blem,we propose a deep learning driven feature-based approach.An advanced steganalysis neural network is used to extract steganographic features,different pairs of training images embedded with steganographic algorithms can obtain diverse features of each algorithm.Then a multi-classifier implemented as lightgbm is used to predict the matching algorithm.Experimental results on four types of JPEG steganographic algorithms prove that the proposed method can improve the detection accuracy in the scenario of steganographic algorithm mismatch.展开更多
The global rise in non-communicable diseases(NCDs)presents significant public health challenges.Effectively managing and preventing NCDs necessitates a thorough understanding of their causes and progression,which can ...The global rise in non-communicable diseases(NCDs)presents significant public health challenges.Effectively managing and preventing NCDs necessitates a thorough understanding of their causes and progression,which can be achieved through a lifecourse approach to determine past exposures’impact before NCD onset.However,this approach requires robust backing from data,specifically lifecourse cohort data,which are generally insufficient.To overcome this obstacle,three primary strategies have been employed to establish such cohorts:active follow-up cohorts,registry-based datasets,and technology-based data collection and simulation methods.展开更多
Cross polarization(CP)is a widely used solid-state nuclear magnetic resonance(NMR)technique for enhancing the polarization of dilute S spins from much larger polarization of abundant I spins such as 1 H.To achieve suc...Cross polarization(CP)is a widely used solid-state nuclear magnetic resonance(NMR)technique for enhancing the polarization of dilute S spins from much larger polarization of abundant I spins such as 1 H.To achieve such a polarization transfer,the I spin should either be spin-locked or be converted to the dipolar ordered state through adiabatic demagnetization in the rotating frame.In this work,we analyze the spin dynamics of the Hartmann-Hahn CP(HHCP)utilizing the 1 H spin-locking,and the dipolar-order CP(DOCP)having the 1 H adiabatic demagnetization.We further propose an adiabatic demagnetization CP(ADCP)where a constant radio-frequency pulse is applied on the S spin while 1 H is adiabatically demagnetized.Our analyses indicate that ADCP utilizes the adiabatic passage to effectively achieve the polarization transfer from the 1 H to S spins.In addition,the dipolar ordered state generated during the 1 H demagnetization process could also be converted into the observable S polarization through DOCP,further enhancing the polarized signals.It is shown by both static and magic-angle-spinning(MAS)NMR experiments that ADCP has dramatically broadened the CP matching condition over the other CP schemes.Various samples have been used to demonstrate the polarization transfer efficiency of this newly proposed ADCP scheme.展开更多
High piezoelectric properties and superior thermal stability are both important indicators of piezoelectric ceramics serving at high temperature.However,since these properties are usually mutually exclusive,high perfo...High piezoelectric properties and superior thermal stability are both important indicators of piezoelectric ceramics serving at high temperature.However,since these properties are usually mutually exclusive,high performance and superior thermal stability are hard to achieve simultaneously.Here we report that a high piezoelectricity(d_(33)∼562 pC/N)and superior thermal stability(the variation is within 7%from 20 to 330℃)were both achieved in 0.4 mol%ZnO-doped 0.02Pb(Sb_(1/2)Nb_(1/2))-0.51PbZrO_(3)-0.47PbTiO_(3) by high-temperature poling.Compared with traditional poling method,high-temperature poling method forms a small-sized and highly oriented domain structure,which can effectively improve the piezoelectric and dielectric properties of piezoelectric ceramics.At the same time,the enhanced pinning effect of defect ions and stabilized domain structure due to high-temperature poling also contribute to the superior temperature stability of the piezoelectric and dielectric properties.This work provides an effective method for designing piezoelectric materials with high performance and good temperature stability for high temperature sensor applications.展开更多
Benefiting from the large Stokes shift between fluorescence and phosphorescence,fluorescence/phosphorescence dual-emitting carbon dots(CDs)have gradually entered at the stage of single-phase white light-emitting diode...Benefiting from the large Stokes shift between fluorescence and phosphorescence,fluorescence/phosphorescence dual-emitting carbon dots(CDs)have gradually entered at the stage of single-phase white light-emitting diodes(WLEDs)as‘green material'.However,most of the developed dual-emitting CDs have weak phosphorescence,short emission wavelength and narrow emission band,resulting in relatively bluish white light emission and low color rendering index(CRI).Herein,an ultrabroad-band fluorescence/phosphorescence dual-emitting CD-based material(UB-CD@BA)is prepared by thermal treatment of boric acid(BA)and CDs with large conjugated structure.The stable covalent bonding between CDs and BA,as well as three-dimensional spatial restriction effect of selfpolymerization BA molecules around CDs during long-term heating efficiently rigidified the single/triplet excited states of CDs from non-radiative deactivation,thus producing strong dual emissive materials with the high phosphorescence quantum yield of 21%.Remarkable,the prepared UB-CD@BA powders exhibit bright pure white light emission with Commission Internationale de l'Eclairage(CIE)coordinates of(0.32,0.33)and the highest reported full width at half maximum of 250 nm.Based on the unique characteristics of UB-CD@BA,it was used as a color conversion layer to prepare a WLED with CIE coordinates of(0.35,0.33)and the CRI value of 87.展开更多
Neuromorphic computing has the potential to achieve the requirements of the next-generation artificial intelligence(AI)systems,due to its advantages of adaptive learning and parallel computing.Meanwhile,biocomputing h...Neuromorphic computing has the potential to achieve the requirements of the next-generation artificial intelligence(AI)systems,due to its advantages of adaptive learning and parallel computing.Meanwhile,biocomputing has seen ongoing development with the rise of synthetic biology,becoming the driving force for new generation semiconductor synthetic biology(SemiSynBio)technologies.DNA-based biomolecules could potentially perform the functions of Boolean operators as logic gates and be used to construct artificial neural networks(ANNs),providing the possibility of executing neuromorphic computing at the molecular level.Herein,we briefly outline the principles of neuromorphic computing,describe the advances in DNA computing with a focus on synthetic neuromorphic computing,and summarize the major challenges and prospects for synthetic neuromorphic computing.We believe that constructing such synthetic neuromorphic circuits will be an important step toward realizing neuromorphic computing,which would be of widespread use in biocomputing,DNA storage,information security,and national defense.展开更多
Composite coatings or films with polytetrafluoroethylene(PTFE)are typically utilized to offer superhydrophobic surfaces.However,the superhydrophobic surfaces usually have limited durability and require complicated fab...Composite coatings or films with polytetrafluoroethylene(PTFE)are typically utilized to offer superhydrophobic surfaces.However,the superhydrophobic surfaces usually have limited durability and require complicated fabrication methods.Herein,we report the successful integration of PTFE with ZnO ceramics to achieve superhydrophobicity via a one-step sintering method,cold sintering process(CSP),at 300℃.(1–x)ZnO–x PTFE ceramic composites with x ranging from 0 to 70 vol%are densified with relative density of over 97%.Micro/nano-scale PTFE polymer is dispersed among ZnO grains forming polymer grain boundary phases,which modulate surface morphology and surface energy of the ZnO–PTFE ceramic composites.For the 60 vol%ZnO–40 vol%PTFE ceramic composite,superhydrophobic properties are optimized with static water contact angles(WCAs)and sliding angles(SAs)of 162°and 7°,respectively.After abrading into various thicknesses(2.52,2.26,and 1.99 mm)and contaminating with graphite powders on the surface,WCA and SA are still maintained with a high level of 157°–160°and 7°–9.3°,respectively.This work indicates that CSP provides a promising pathway to integrate polymers with ceramics to realize stable superhydrophobicity.展开更多
Although employed to release growth factors(GFs)for regenerative medicine,platelet-rich plasma(PRP)has been hindered by issues like burst effect.Based on collagen sponge scaffolds(CSSs)modified with polydopamine(pDA),...Although employed to release growth factors(GFs)for regenerative medicine,platelet-rich plasma(PRP)has been hindered by issues like burst effect.Based on collagen sponge scaffolds(CSSs)modified with polydopamine(pDA),a novel dermal regeneration template(DRT)was designed.However,whether it could efficiently deliver PRP and even foster wound healing remained unclear.In this work,after PRP was prepared and pDA-modified CSSs(pDA-CSSs)were fabricated,microscopic observation,GFs release assay and in-vitro biological evaluations of pDA-CSSs with PRP(pDA-CSS@PRP)were performed,followed by BALA-C/nu mice full-thickness skin defects implanted with pDA-CSS@PRP covered by grafted skins(termed as a One-step strategy).As a result,scanning electron microscope demonstrated more immobilized platelets on pDA-CSS′surface with GFs’controlled release via enzyme-linked immunosorbent assay,compared with CSSs.In line with enhanced in-vitro proliferation,adhesion and migration of keratinocytes&endothelial cells,pDA-CSS@PRP were histologically revealed to accelerate wound healing with less scar via rapid angiogenesis,arrangement of more mature collagen,guiding cells to spread,etc.In conclusion,pDA-CSSs have potential to serve as a novel DRT capable of delivering PRP,which may foster full-thickness skin defect healing by means of a One-step strategy.展开更多
Metal-free room-temperature phosphorescence(RTP)materials are of great significance for many applications;however,they usually exhibit low efficiency and weak intensity.This article reports a new strategy for the prep...Metal-free room-temperature phosphorescence(RTP)materials are of great significance for many applications;however,they usually exhibit low efficiency and weak intensity.This article reports a new strategy for the preparation of a high-efficiency and strong RTP materials from crystalline thermal-annealed carbon dots(CDs)and boric acid(BA)composite(g-t-CD@BA)through grinding-induced amorphous to crystallization transition.Amorphous thermal-annealed CDs and BA composite(t-CD@BA)is prepared following a thermal melting and super-cooling route,where the CDs are fully dispersed in molten BA liquid and uniformly frozen in an amorphous thermal annealed BA matrix after super-cooling to room temperature.Upon grinding treatment,the fracture and fragmentation caused by grinding promote the transformation of the high-energy amorphous state to the lower energy crystalline counterparts.As a result,the CDs are uniformly in situ embedded in the BA crystal matrix.This method affords maximum uniform embedding of the CDs in the BA crystals,decreases nonradiative decay,and promotes intersystem crossing by restraining the free vibration of the CDs,thus producing strong RTP materials with the highest reported phosphorescence quantum yield(48%).Remarkably,RTP from g-t-CD@BA powder is strong enough to illuminate items with a delay time exceeding 9 s.展开更多
Motor-pump assembly is the core component of the Aerospace Electro-hydrostatic Actuator(EHA).Thus,the design of the motor pump can be very challenging under conditions of high speed and wide pressure range,especially ...Motor-pump assembly is the core component of the Aerospace Electro-hydrostatic Actuator(EHA).Thus,the design of the motor pump can be very challenging under conditions of high speed and wide pressure range,especially in particular working mediums.Our ultimate goal is to pursue better flow characteristics under a wide range of working conditions.In this paper,we built a sub-model of the main friction interfaces and a model of single-shaft coaxial motor-pump assembly adopting the method of hierarchical modeling.The experimental investigation of the output characteristics was mainly carried out in a phosphate ester medium environment.Then,the flow characteristics were compared and analyzed with the simulation results.Results indicated that the flow characteristics of the motor-pump assembly could be accurately simulated by the model and quite severe in a low speed and high-pressure environment.展开更多
文摘As a product of the deep integration of financial technology and the digital economy,digital finance plays a significant role in promoting the development of new quality productivity.This paper first elaborates on the connotations of new quality productivity and digital finance and analyzes the mechanisms by which digital finance promotes the development of new quality productivity from both theoretical and practical perspectives.The aim is to explore the value digital finance brings to the development of new quality productivity,along with the challenges it faces,in order to propose corresponding policy recommendations.
基金supported by National Natural Science Foundation of China under Grant 61822407,Grant 62074161,and Grant 11634002in part by the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(CAS)under Grant QYZDB-SSW-JSC012+3 种基金in part by the National Key Research and Development Program of China under Grant 2016YFB0400105 and Grant 2017YFB0403000in part by the Youth Innovation Promotion Association of CASin part by the University of Chinese Academy of Sciencesand in part by the Opening Project of Key Laboratory of Microelectronic Devices&Integrated Technology,Institute of Microelectronics,CAS.
文摘A pre-ohmic micro-patterned recess process,is utilized to fabricate Ti/Al/Ti/TiN ohmic contact to an ultrathin-barrier(UTB)AlGaN/GaN heterostructure,featuring a significantly reduced ohmic contact resistivity of 0.56Ω·mm at an alloy temperature of 550℃.The sheet resistances increase with the temperature following a power law with the index of +2.58,while the specific contact resistivity decreases with the temperature.The contact mechanism can be well described by thermionic field emission(TFE).The extracted Schottky barrier height and electron concentration are 0.31 eV and 5.52×10^(18) cm^(−3),which suggests an intimate contact between ohmic metal and the UTB-AlGaN as well as GaN buffer.A good correlation between ohmic transfer length and the micro-pattern size is revealed,though in-depth investigation is needed.A preliminary CMOS-process-compatible metal-insulator-semiconductor high-mobility transistor(MIS-HEMT)was fabricated with the proposed Au-free ohmic contact technique.
文摘In this paper,137“First-class universities”and“First-class discipline”construction universities in China are selected as the objects of investigation to analyzes the present situation and characteristics of the game design of University Library in China.Taking the university library in other countries as the reference object,this paper compares the differences of the game design of University Library in China and other countries,sums up the deficiency of the gamification service practice in Chinese university libraries.At last,this paper proposes an optimization path of the gamification design of Chinese University Library from six aspects of game type,game service object,game interactive mode,game application,game development and game playability.
基金The National Key R&D Program of China under contract No.2020YFA0607603the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA23050402+1 种基金the National Natural Science Foundation of China under contract Nos 41776155 and U1906216the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2018SDKJ0501-3。
文摘Eutrophication in coastal area has become more and more serious and mariculture potential is a main cause.Although there are some quantitative research on nutrient loads in national and global perspective,the calculation method problems make the results controversial.In this paper,the farming activities are divided into fed culture types(include cage culture and pond culture)and extractive culture types(e.g.seaweed,filter-feeding shellfish culture).Based on the annual yield of China in 2019 and feed coefficient of fed culture types and carbon(C),nitrogen(N),and phosphorus(P)content of extractive culture types,the annual nutrient loads was estimated.The results showed that to coastal region of China(1)annual nutrient released by fed culture types were about58451 t of N,9081 t of P,and annual nutrient removed by harvest of extractive culture types were 109245 t of N,11980 t of P and 1.86×10^(6)t of C.Overall,the net amount of nutrient removed annually by mariculture industry were 50794 t of N and 2901 t of P.(2)The nutrient released from mariculture industry influenced nutrient stoichiometry.Pond farming and seaweed farming had the potential of increasing the molar concentration ratio of N and P(N:P),while cage farming and bivalve farming decreased the N:P.(3)Due to different mariculture types and layouts in the coastal regions in China,N and P loading were regional different.Among the coastal regions in China,net release of nutrient from mariculture occurred only in Hainan and Guangxi regions,while in the other regions,N and P were completely removed by harvest.We suggest decrease the amount of fed culture types and increase the amount of integrated culture with extractive culture types.This study will help to adjust mariculture structure and layout at the national level to reduce the environmental impact.
基金Prevention&Control of COVID-19 Program of Soochow Securities,Grant/Award Number:JJ12700520Postgraduate Research&Practice Innovation Program of Jiangsu Province,Grant/Award Number:KYCX20_2684.
文摘Background Major infectious disease has become a serious threat to people’s health worldwide.As the world’s largest healthcare workforce and the core forces fighting against the epidemic,nurses are on the frontline of this battle.A number of ethical issues have given rise to numerous concerns that have largely affected nurses in different ways as they respond to the epidemic.In addition,excessive expectations from people can exert undue pressure,which can easily lead to burnout in nurses.Methods In this consensus,the expert panel method was used to develop and reach a consensus.The members involved in the formation of the consensus included an expert discussion panel and a consensus writing expert group,a methodologist,and four secretaries.After 16 rounds of online expert consultation and two rounds of expert panel meetings,the writing team analyzed and reviewed the 78 amendments suggested by the experts to develop a consensus on nursing ethics for prevention and control of major infectious disease outbreaks based on the ethical vision of life care.Results This expert consensus focuses on five essential domains:the responsibilities and rights of nurses,the nurse-patient relationship,the doctor-nurse relationship,and the relationship between society and nurses throughout the epidemic.Conclusions We hope this consensus can help nurses better understand and respond to the ethical issues and challenges in public health emergencies,and raise reasonable public expectations of the roles and responsibilities of nurses in these situations.
基金This study was funded by the National Natural Science Foundation of China(Grant number 72074164)the Chinese Academy of Medical Sciences(Grant number 2020-JKCS-024)the Humanity and Social Science Youth Foundation of the Ministry of Education of China(Grant number 20YJCZH088).
基金supported by the National Natural Science Foundation of China (NSFC)under grant No.U1836102Anhui Science and Technology Key Special Program under the grant No.201903a050200162020 Domestic Visiting and Training Program for Outstanding Young Backbone Talents in Colleges and Universities under the grant No.gxgnfx2020132.
文摘The goal of steganalysis is to detect whether the cover carries the secret information which is embedded by steganographic algorithms.The traditional ste-ganalysis detector is trained on the stego images created by a certain type of ste-ganographic algorithm,whose detection performance drops rapidly when it is applied to detect another type of steganographic algorithm.This phenomenon is called as steganographic algorithm mismatch in steganalysis.To resolve this pro-blem,we propose a deep learning driven feature-based approach.An advanced steganalysis neural network is used to extract steganographic features,different pairs of training images embedded with steganographic algorithms can obtain diverse features of each algorithm.Then a multi-classifier implemented as lightgbm is used to predict the matching algorithm.Experimental results on four types of JPEG steganographic algorithms prove that the proposed method can improve the detection accuracy in the scenario of steganographic algorithm mismatch.
基金Supported by the National Natural Science Foundation of China(42271433)the National Key R&D Program of China(2023YFC3604701)+4 种基金the“0 to 1”Innovation Research Project of Sichuan University(2023CX21)the Key R&D Project of Sichuan Province(2023YFS0251)Renmin Hospital of Wuhan University(JCRCYG-2022-003)the Wuhan University Specific Fund for Major School-level Internationalization Initiatives(WHU-GJZDZX-PT07)the International Institute of Spatial Lifecourse Health(ISLE).
文摘The global rise in non-communicable diseases(NCDs)presents significant public health challenges.Effectively managing and preventing NCDs necessitates a thorough understanding of their causes and progression,which can be achieved through a lifecourse approach to determine past exposures’impact before NCD onset.However,this approach requires robust backing from data,specifically lifecourse cohort data,which are generally insufficient.To overcome this obstacle,three primary strategies have been employed to establish such cohorts:active follow-up cohorts,registry-based datasets,and technology-based data collection and simulation methods.
基金supported by the NSF Cooperative Agreement DMR-1644779the State of Florida.X.H.P.acknowledges the supports from the National Key R&D Program of China(Grants No.2018YFA0306600)+1 种基金the National Science Foundation of China(Grants No.11927811,12150014)Anhui Initiative in Quantum Information Technologies(Grant No.AHY050000).
文摘Cross polarization(CP)is a widely used solid-state nuclear magnetic resonance(NMR)technique for enhancing the polarization of dilute S spins from much larger polarization of abundant I spins such as 1 H.To achieve such a polarization transfer,the I spin should either be spin-locked or be converted to the dipolar ordered state through adiabatic demagnetization in the rotating frame.In this work,we analyze the spin dynamics of the Hartmann-Hahn CP(HHCP)utilizing the 1 H spin-locking,and the dipolar-order CP(DOCP)having the 1 H adiabatic demagnetization.We further propose an adiabatic demagnetization CP(ADCP)where a constant radio-frequency pulse is applied on the S spin while 1 H is adiabatically demagnetized.Our analyses indicate that ADCP utilizes the adiabatic passage to effectively achieve the polarization transfer from the 1 H to S spins.In addition,the dipolar ordered state generated during the 1 H demagnetization process could also be converted into the observable S polarization through DOCP,further enhancing the polarized signals.It is shown by both static and magic-angle-spinning(MAS)NMR experiments that ADCP has dramatically broadened the CP matching condition over the other CP schemes.Various samples have been used to demonstrate the polarization transfer efficiency of this newly proposed ADCP scheme.
基金financially supported by the National Key Research and Development Program of China(No.2018YFC0308603)the Pilot Technology for Chinese Academy of Sciences(No.XDA2203003)the National Natural Science Foundation of China(Nos.51972321 and 51879269)。
文摘High piezoelectric properties and superior thermal stability are both important indicators of piezoelectric ceramics serving at high temperature.However,since these properties are usually mutually exclusive,high performance and superior thermal stability are hard to achieve simultaneously.Here we report that a high piezoelectricity(d_(33)∼562 pC/N)and superior thermal stability(the variation is within 7%from 20 to 330℃)were both achieved in 0.4 mol%ZnO-doped 0.02Pb(Sb_(1/2)Nb_(1/2))-0.51PbZrO_(3)-0.47PbTiO_(3) by high-temperature poling.Compared with traditional poling method,high-temperature poling method forms a small-sized and highly oriented domain structure,which can effectively improve the piezoelectric and dielectric properties of piezoelectric ceramics.At the same time,the enhanced pinning effect of defect ions and stabilized domain structure due to high-temperature poling also contribute to the superior temperature stability of the piezoelectric and dielectric properties.This work provides an effective method for designing piezoelectric materials with high performance and good temperature stability for high temperature sensor applications.
基金the support from the National Natural Science Foundation of China(Nos.52002152 and 62005106)the Natural Science Foundation of Jiangsu Province(Nos.BK20190864 and BK20190865)the Primary Research&Development Plan of Zhenjiang-Modern Agriculture(No.NY2021007)。
文摘Benefiting from the large Stokes shift between fluorescence and phosphorescence,fluorescence/phosphorescence dual-emitting carbon dots(CDs)have gradually entered at the stage of single-phase white light-emitting diodes(WLEDs)as‘green material'.However,most of the developed dual-emitting CDs have weak phosphorescence,short emission wavelength and narrow emission band,resulting in relatively bluish white light emission and low color rendering index(CRI).Herein,an ultrabroad-band fluorescence/phosphorescence dual-emitting CD-based material(UB-CD@BA)is prepared by thermal treatment of boric acid(BA)and CDs with large conjugated structure.The stable covalent bonding between CDs and BA,as well as three-dimensional spatial restriction effect of selfpolymerization BA molecules around CDs during long-term heating efficiently rigidified the single/triplet excited states of CDs from non-radiative deactivation,thus producing strong dual emissive materials with the high phosphorescence quantum yield of 21%.Remarkable,the prepared UB-CD@BA powders exhibit bright pure white light emission with Commission Internationale de l'Eclairage(CIE)coordinates of(0.32,0.33)and the highest reported full width at half maximum of 250 nm.Based on the unique characteristics of UB-CD@BA,it was used as a color conversion layer to prepare a WLED with CIE coordinates of(0.35,0.33)and the CRI value of 87.
文摘Neuromorphic computing has the potential to achieve the requirements of the next-generation artificial intelligence(AI)systems,due to its advantages of adaptive learning and parallel computing.Meanwhile,biocomputing has seen ongoing development with the rise of synthetic biology,becoming the driving force for new generation semiconductor synthetic biology(SemiSynBio)technologies.DNA-based biomolecules could potentially perform the functions of Boolean operators as logic gates and be used to construct artificial neural networks(ANNs),providing the possibility of executing neuromorphic computing at the molecular level.Herein,we briefly outline the principles of neuromorphic computing,describe the advances in DNA computing with a focus on synthetic neuromorphic computing,and summarize the major challenges and prospects for synthetic neuromorphic computing.We believe that constructing such synthetic neuromorphic circuits will be an important step toward realizing neuromorphic computing,which would be of widespread use in biocomputing,DNA storage,information security,and national defense.
基金The authors acknowledge the support from the funding of the National Natural Science Foundation of China(Grant No.51877016)the Fok Ying-Tong Education Foundation,China(Grant No.171050)Science and Technology Project of State Grid Co.,Ltd.,China(Grant No.5500-202399372A-2-2-ZB).
文摘Composite coatings or films with polytetrafluoroethylene(PTFE)are typically utilized to offer superhydrophobic surfaces.However,the superhydrophobic surfaces usually have limited durability and require complicated fabrication methods.Herein,we report the successful integration of PTFE with ZnO ceramics to achieve superhydrophobicity via a one-step sintering method,cold sintering process(CSP),at 300℃.(1–x)ZnO–x PTFE ceramic composites with x ranging from 0 to 70 vol%are densified with relative density of over 97%.Micro/nano-scale PTFE polymer is dispersed among ZnO grains forming polymer grain boundary phases,which modulate surface morphology and surface energy of the ZnO–PTFE ceramic composites.For the 60 vol%ZnO–40 vol%PTFE ceramic composite,superhydrophobic properties are optimized with static water contact angles(WCAs)and sliding angles(SAs)of 162°and 7°,respectively.After abrading into various thicknesses(2.52,2.26,and 1.99 mm)and contaminating with graphite powders on the surface,WCA and SA are still maintained with a high level of 157°–160°and 7°–9.3°,respectively.This work indicates that CSP provides a promising pathway to integrate polymers with ceramics to realize stable superhydrophobicity.
基金supported by the Natural Science Foundation of Guangdong Province[No.2020A151501108]the Guangdong Province Key Field R&D Program Project[No.2020B1111150001],the Science and Technology Innovation Project of Guangdong Province[No.2018KJYZ005]the Natural Science Foundation of Tibet Autonomous Region[No.XZ2017ZR-ZY021].
文摘Although employed to release growth factors(GFs)for regenerative medicine,platelet-rich plasma(PRP)has been hindered by issues like burst effect.Based on collagen sponge scaffolds(CSSs)modified with polydopamine(pDA),a novel dermal regeneration template(DRT)was designed.However,whether it could efficiently deliver PRP and even foster wound healing remained unclear.In this work,after PRP was prepared and pDA-modified CSSs(pDA-CSSs)were fabricated,microscopic observation,GFs release assay and in-vitro biological evaluations of pDA-CSSs with PRP(pDA-CSS@PRP)were performed,followed by BALA-C/nu mice full-thickness skin defects implanted with pDA-CSS@PRP covered by grafted skins(termed as a One-step strategy).As a result,scanning electron microscope demonstrated more immobilized platelets on pDA-CSS′surface with GFs’controlled release via enzyme-linked immunosorbent assay,compared with CSSs.In line with enhanced in-vitro proliferation,adhesion and migration of keratinocytes&endothelial cells,pDA-CSS@PRP were histologically revealed to accelerate wound healing with less scar via rapid angiogenesis,arrangement of more mature collagen,guiding cells to spread,etc.In conclusion,pDA-CSSs have potential to serve as a novel DRT capable of delivering PRP,which may foster full-thickness skin defect healing by means of a One-step strategy.
基金the National Natural Science Foundation of China(No.52002152,62005106 and 61922091)the Natural Science Foundation of Jiangsu(BK20190864 and BK20190865)+3 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions(19KJB430014)the Science and Technology Development Fund of Macao SAR(0040/2019/A1,0128/2020/A3,0131.2020.A3 and 0073/2019/AMJ)Fund from the University of Macao(SRG2019‐00163‐IAPME)the High-Tech Research Key Laboratory of Zhenjiang(SS2018002).
文摘Metal-free room-temperature phosphorescence(RTP)materials are of great significance for many applications;however,they usually exhibit low efficiency and weak intensity.This article reports a new strategy for the preparation of a high-efficiency and strong RTP materials from crystalline thermal-annealed carbon dots(CDs)and boric acid(BA)composite(g-t-CD@BA)through grinding-induced amorphous to crystallization transition.Amorphous thermal-annealed CDs and BA composite(t-CD@BA)is prepared following a thermal melting and super-cooling route,where the CDs are fully dispersed in molten BA liquid and uniformly frozen in an amorphous thermal annealed BA matrix after super-cooling to room temperature.Upon grinding treatment,the fracture and fragmentation caused by grinding promote the transformation of the high-energy amorphous state to the lower energy crystalline counterparts.As a result,the CDs are uniformly in situ embedded in the BA crystal matrix.This method affords maximum uniform embedding of the CDs in the BA crystals,decreases nonradiative decay,and promotes intersystem crossing by restraining the free vibration of the CDs,thus producing strong RTP materials with the highest reported phosphorescence quantum yield(48%).Remarkably,RTP from g-t-CD@BA powder is strong enough to illuminate items with a delay time exceeding 9 s.
基金This study was co-supported by the Chinese Civil Aircraft Project(No.MJ-2017-S49)China Postdoctoral Science Foundation(No.2021M700331).
文摘Motor-pump assembly is the core component of the Aerospace Electro-hydrostatic Actuator(EHA).Thus,the design of the motor pump can be very challenging under conditions of high speed and wide pressure range,especially in particular working mediums.Our ultimate goal is to pursue better flow characteristics under a wide range of working conditions.In this paper,we built a sub-model of the main friction interfaces and a model of single-shaft coaxial motor-pump assembly adopting the method of hierarchical modeling.The experimental investigation of the output characteristics was mainly carried out in a phosphate ester medium environment.Then,the flow characteristics were compared and analyzed with the simulation results.Results indicated that the flow characteristics of the motor-pump assembly could be accurately simulated by the model and quite severe in a low speed and high-pressure environment.
