The use of redox-active organic electrode materials in energy storage is restricted due to their inferior solvent resistance,abysmal conductivity,and the resultant low practical capacity.To address these issues,a clas...The use of redox-active organic electrode materials in energy storage is restricted due to their inferior solvent resistance,abysmal conductivity,and the resultant low practical capacity.To address these issues,a class of bipolar p-phenylenediimidazole-based small-molecule compounds are designed and fabricated.Theπ-conjugated backbone of these small molecules allows for electron delocalization on a big conjugation plane,endowing them with good conductivity and reaction reversibility.Furthermore,when the para-positions of phenylene are occupied by hydroxyl groups,as-formed intramolecular hydrogen bonds(N-H...O)between phenolic hydroxyl groups and the–NH groups of imidazole rings further enhance the structural planarity,resulting in higherπ-conjugation degree and better conductivity,and thus higher utilization of active sites and electrode capacity,proved by both experimental results and theoretical calculations.The optimized composite electrode DBNQ@rGO-45 shows a high specific capacity(∼308 mA h g^(−1)at 100 mA g^(−1))and a long cycling stability(112.9 mA h g^(−1)after 6000 cycles at 2000 mA g^(−1)).The significantly better electrochemical properties for hydroxyl group-containing compounds than those without hydroxyl groups attributed to intramolecular hydrogen bond-induced conjugation enhancement will inspire the structure design of organic electrodes for better energy storage.展开更多
This study focused on the investigation of the edge effect of diamond films deposited by microwave plasma chemical vapor de-position.Substrate bulge height△h is a factor that affects the edge effect,and it was used t...This study focused on the investigation of the edge effect of diamond films deposited by microwave plasma chemical vapor de-position.Substrate bulge height△h is a factor that affects the edge effect,and it was used to simulate plasma and guide the diamond-film deposition experiments.Finite-element software COMSOL Multiphysics was used to construct a multiphysics(electromagnetic,plasma,and fluid heat transfer fields)coupling model based on electron collision reaction.Raman spectroscopy and scanning electron microscopy were performed to characterize the experimental growth and validate the model.The simulation results reflected the experimental trends observed.Plasma discharge at the edge of the substrate accelerated due to the increase in△h(△h=0-3 mm),and the values of electron density(n_(c)),molar concentration of H(C_(H)),and molar concentration of CH_(3)(C_(CH_(3)))doubled at the edge(for the special concave sample with△h=−1 mm,the active chemical groups exhibited a decreased molar concentration at the edge of the substrate).At=0-3 mm,a high diamond growth rate and a large diamond grain size were observed at the edge of the substrate,and their values increased with.The uniformity of film thickness decreased with.The Raman spectra of all samples revealed the first-order characteristic peak of dia-mond near 1332 cm^(−1).When△h=−1 mm,tensile stress occurred in all regions of the film.When△h=1-3 mm,all areas in the film ex-hibited compressive stress.展开更多
Lithium-sulfur(Li-S)batteries have been recognized as one of the most promising candidates for nextgeneration portable electronic devices,owing to their extremely high energy density and low cost.However,the dissoluti...Lithium-sulfur(Li-S)batteries have been recognized as one of the most promising candidates for nextgeneration portable electronic devices,owing to their extremely high energy density and low cost.However,the dissolution of lithium polysulfides(LiPSs)and consequent"shuttle effect"seriously hinder the practical deployment of Li-S batteries.Herein,multi-metal oxide nanorods named attapulgite are proposed as multifunctional ionic sieve to immobilize LiPSs and further promote the regulation of LiPSs.Attapulgite,consisting of Al,Mg,Fe,Si and O ions,possesses more polar sites to immobilize LiPSs in comparison with single metal oxides.In addition,the catalytic nature(Fe ions)of attapulgite avails the LiPSs conversion reaction,which is further confirmed by the linear sweep voltammetry and electrochemical impedance spectroscopy.Benefited from the synergistic effect of multi-metal oxide and conductive carbon,the Li-S battery with the modified separator delivers remarkable discharge capacities of 1059.4 mAh g-1 and 792.5 mAh g-1 for the first and 200th cycle at 0.5 C,respectively.The work presents an effective way to improve the electrochemical performance of Li-S batteries by employing attapulgite nanorods assisted separator surface engineering.展开更多
Due to the remarkable growth rate compared to another growth methods for gallium nitride(GaN)growth,hydride vapor phase epitaxy(HVPE)is now the only method for mass product GaN substrates.In this review,commercial HVP...Due to the remarkable growth rate compared to another growth methods for gallium nitride(GaN)growth,hydride vapor phase epitaxy(HVPE)is now the only method for mass product GaN substrates.In this review,commercial HVPE systems and the GaN crystals grown by them are demonstrated.This article also illustrates some innovative attempts to develop homebuilt HVPE systems.Finally,the prospects for the further development of HVPE for GaN crystal growth in the future are also discussed.展开更多
Periodic nitrogen-doped homoepitaxial nano-multilayers were grown by microwave plasma chemical vapor deposition. The residual time of gases(such as CH4and N2) in the chamber was determined by optical emission spectros...Periodic nitrogen-doped homoepitaxial nano-multilayers were grown by microwave plasma chemical vapor deposition. The residual time of gases(such as CH4and N2) in the chamber was determined by optical emission spectroscopy to determine the nano-multilayer growth process, and thin, nanoscale nitrogen-doped layers were obtained. The highest toughness of 18.2 MPa·m^(1/2)under a Young’s modulus of1000 GPa is obtained when the single-layer thickness of periodic nitrogen-doped nano-multilayers is about 96 nm. The fracture toughness of periodic nitrogen-doped CVD layer is about 2.1 times that of the HPHT seed substrate. Alternating tensile and compressive stresses are derived from periodic nitrogen doping;hence, the fracture toughness is significantly improved. Single-crystal diamond with a high toughness demonstrates wide application prospects for high-pressure anvils and single-point diamond cutting tools.展开更多
Gibberellin(GA)plays a major role in controlling Brassica rapa stalk development.As an essential negative regulator of GA signal transduction,DELLA proteins may exert significant effects on stalk development.However,t...Gibberellin(GA)plays a major role in controlling Brassica rapa stalk development.As an essential negative regulator of GA signal transduction,DELLA proteins may exert significant effects on stalk development.However,the regulatory mechanisms underlying this regulation remain unclear.In this study,we report highly efficient and inheritable mutagenesis using the CRISPR/Cas9 gene editing system in BraPDS(phytoene desaturase)and BraRGL1(key DELLA protein)genes.We observed a loss-of-function mutation in BraRGL1 due to two amino acids in GRAS domain.The flower bud differentiation and bolting time of BraRGL1 mutants were significantly advanced.The expression of GA-regulatory protein(BraGASA6),flowering related genes(BraSOC1,BraLFY),expansion protein(BraEXPA11)and xyloglucan endotransferase(BraXTH3)genes was also significantly upregulated in these mutants.BraRGL1-overexpressing plants displayed the contrasting phenotypes.BraRGL1 mutants were more sensitive to GA signaling.BraRGL1 interacted with BraSOC1,and the interaction intensity decreased after GA3 treatment.In addition,BraRGL1 inhibited the transcription-activation ability of BraSOC1 for BraXTH3 and BraLFY genes,but the presence of GA3 enhanced the activation ability of BraSOC1,suggesting that the BraRGL1-BraSOC1 module regulates bolting and flowering of B.rapa through GA signal transduction.Thus,we hypothesized that BraRGL1 is degraded,and BraSOC1 is released in the presence of GA3,which promotes the expression of BraXTH3 and BraLFY,thereby inducing stalk development in B.rapa.Further,the BraRGL1-M mutant promoted the flower bud differentiation without affecting the stalk quality.Thus,BraRGL1 can serve as a valuable target for the molecular breeding of early maturing varieties.展开更多
Handling emotions in human‐computer dialogues has emerged as a challenging task which requires artificial intelligence systems to generate emotional responses by jointly perceiving the emotion involved in the input p...Handling emotions in human‐computer dialogues has emerged as a challenging task which requires artificial intelligence systems to generate emotional responses by jointly perceiving the emotion involved in the input posts and incorporating it into the gener-ation of semantically coherent and emotionally reasonable responses.However,most previous works generate emotional responses solely from input posts,which do not take full advantage of the training corpus and suffer from generating generic responses.In this study,we introduce a hierarchical semantic‐emotional memory module for emotional conversation generation(called HSEMEC),which can learn abstract semantic conver-sation patterns and emotional information from the large training corpus.The learnt semantic and emotional knowledge helps to enrich the post representation and assist the emotional conversation generation.Comprehensive experiments on a large real‐world conversation corpus show that HSEMEC can outperform the strong baselines on both automatic and manual evaluation.For reproducibility,we release the code and data publicly at:https://github.com/siat‐nlp/HSEMEC‐code‐data.展开更多
In this study,uniform diamond films with a diameter of 100 mm were deposited in a 15 kW/2.45 GHz ellipsoidal microwave plasma chemical vapour deposition system.A phenomenological model previously developed by our grou...In this study,uniform diamond films with a diameter of 100 mm were deposited in a 15 kW/2.45 GHz ellipsoidal microwave plasma chemical vapour deposition system.A phenomenological model previously developed by our group was used to simulate the distribution of the electric strength and electron density of plasma.Results indicate that the electric field in the cavity includes multiple modes,i.e.TM_(02) and TM_(03).When the gas pressure exceeds 10 kPa,the electron density of plasma increases and plasma volume decreases.A T-shaped substrate was developed to achieve uniform temperature,and the substrate was suspended in air fromφ70 to 100 mm,thus eliminating vertical heat dissipation.An edge electric field was added to the system after the introduction of the T-shaped substrate.Moreover,the plasma volume in this case was greater than that in the central electric field but smaller than that in the periphery electric field of the TM_(02) mode.This indicates that the electric field above and below the edge benefits the plasma volume rather than the periphery electric field of the TM_(02) mode.The quality,uniformity and surface morphology of the deposited diamond films were primarily investigated to maintain substrate temperature uniformity.When employing the improved substrate,the thickness unevenness of theφ100 mm diamond film decreased from 22%to 7%.展开更多
Current electronic technology based on silicon is approaching its physical and scientific limits. Carbon-based devices have numer- ous advantages for next generation electronics (e.g., fast speed, low power consumptio...Current electronic technology based on silicon is approaching its physical and scientific limits. Carbon-based devices have numer- ous advantages for next generation electronics (e.g., fast speed, low power consumption and simple process), that when combined with the unique nature of the versatile allotropes of carbon elements, are creating an electronics revolution. Carbon electronics are greatly advancing with new preparations and sophisticated designs. In this perspective, representatives with various dimensions, e.g., carbon nanotubes, graphene, bulk diamond, and their extraordinary performance, are reviewed. The associated state-of-the-art devices and composite hybrid all-carbon structures are also emphasized to reveal their potential in the electronics field. Advances in commercial production have improved the cost effi-ciency, material quality, and device design, accelerating the promise of carbon materials.展开更多
With the deepening application of geographic information web services, as a significant part, geographic information directory service sets up a service transaction platform between the service providers and the servi...With the deepening application of geographic information web services, as a significant part, geographic information directory service sets up a service transaction platform between the service providers and the service requestors, providing one-stop registration, access and management functions of geographic information web services, so it is very important to carry out the research on geographic information directory service. According to the domestic and overseas metadata standards, the service expression-oriented metadata information model for geographic information web service is established, and the discovery mechanism dominated by geographic information service registration and active discovery is realized accordingly. After that, overall design of directory service model is made, and finally the research results are integrated into the geographic information service software NewMapServer and deployment test is made under the Google Cloud Environment Google App Engine, providing a certain reference for sharing the Smart City construction achievements.展开更多
Different amounts of Fe(0.005,0.01,0.03,0.05,and 0.07 wt%)were added to SAC305 to study the shear behavior damage of Fe-doped SAC solder joints under thermal loading(170℃,holding time of 0,250,500,and 750 h).The resu...Different amounts of Fe(0.005,0.01,0.03,0.05,and 0.07 wt%)were added to SAC305 to study the shear behavior damage of Fe-doped SAC solder joints under thermal loading(170℃,holding time of 0,250,500,and 750 h).The results show that during isothermal aging at 170℃,the average shear force of all solder joints decreases with increasing aging time,while the average fracture energy first increases and then decreases,reaching a maximum at 500 h.Minor Fe doping could both increase shear forces and related fracture energy,with the optimum Fe doping amount being 0.03 wt%within the entire aging range.This is because the doping Fe reduces the undercooling of the SAC305 alloy,resulting in the microstructure refining of solder joints.This in turn causes the microstructure changing from network structure(SAC305 joint:eutectic network+β-Sn)to a single matrix structure(0.03Fe-doped SAC305 joint:β-Sn matrix+small compound particles).Specifically,Fe atoms can replace some Cu in Cu_(6)Sn_(5)(both inside the solder joint and at the interface),and then form(Cu,Fe)_(6)Sn_(5) compounds,resulting in an increase in the elastic modulus and nanohardness of the compounds.Moreover,the growth of Cu_(6)Sn_(5) and Cu_(3)Sn intermetallic compounds(IMC)layer are inhibited by Fe doping even after the aging time prolonging,and Fe aggregates near the interface compound to form FeSn_(2).This study is of great significance for controlling the growth of interfacial compounds,stabilizing the microstructures,and providing strengthening strategy for solder joint alloy design.展开更多
Smart city is the development of digital city; as its main supporting technology, the digital city geo-spatial framework has to be upgraded to the temporal-spatial information infrastructure (TSII). first, this paper ...Smart city is the development of digital city; as its main supporting technology, the digital city geo-spatial framework has to be upgraded to the temporal-spatial information infrastructure (TSII). first, this paper proposes the concept and basic framework of smart city and defines the concept of TSII - processes, integration, mining analysis, and share time-stamps geographic data - and the related policy, regulations and standards, technology, facilities, mechanism, and human resources. The framework has four components: the benchmark of time and space, temporal-spatial big data, the cloud service platform and the related supporting environment. Second, the temporal-spatial big data and cloud service platform are elaborated. finally, an application of TSII constructed by the Xicheng District Planning Bureau in Beijing is introduced, which provides a useful reference for the construction of smart city.展开更多
Antioxidant collagen hydrolysates refers to the peptides mixture with antioxidant properties identified from hydrolyzed collagen.Due to its specific structural,biological and physicochemical properties,collagen hydrol...Antioxidant collagen hydrolysates refers to the peptides mixture with antioxidant properties identified from hydrolyzed collagen.Due to its specific structural,biological and physicochemical properties,collagen hydrolysates have been explored as a multifunctional antioxidant in the biomedical field.In this review,we summarize recent advances in antioxidant collagen hydrolysates development.Initially,the preparation process of antioxidant collagen hydrolysates is introduced,including the production and separation methods.Then the effects and the mechanisms of amino acid composition and collagen peptide structure on the antioxidant activity of collagen hydrolysates are reviewed.Finally,the applications of antioxidant collagen hydrolysates in biomedical domains are summarized,with critical discussions about the advantages,current limitations and challenges to be resolved in the future.展开更多
The construction of donor-acceptor(D-A)molecular structure is an attractive strategy to enhance the photocatalytic performance of polymeric semiconductors.Herein,dibenzothiophene(DBT)-4-carbaldehyde as the precursor i...The construction of donor-acceptor(D-A)molecular structure is an attractive strategy to enhance the photocatalytic performance of polymeric semiconductors.Herein,dibenzothiophene(DBT)-4-carbaldehyde as the precursor is introduced into g-C_(3)N_(4)(TCN)prepared by two-step thermal polymerization to construct an intramolecular D-A type copolymer(TCN-DBT_(x)).DFT calculation and experimental results reveal that DBT plays the role of electron donor unit to modify g-C_(3)N_(4).The incorporation of DBT not only adjusts the band gap to improve reduction ability,but also induces an internal electric field with extendingπ-conjugated system for effective charge transfer.As a result,TCN-DBT_(x)exhibits much better photocatalytic performance with an optimal hydrogen production rate of 3334μmol h^(-1)g^(-1),which is 2.5 times that of TCN.This work provides a protocol for preparing high-performance g-C_(3)N_(4)-based photocatalysts toward various applications.展开更多
Chemical vapor deposited(CVD)diamond as a burgeoning multifunctional material with tailored quality and characteristics can be artificially synthesized and controlled for various applications.Correspondingly,the appli...Chemical vapor deposited(CVD)diamond as a burgeoning multifunctional material with tailored quality and characteristics can be artificially synthesized and controlled for various applications.Correspondingly,the application-related“grade”concept associated with materials choice and design was gradually formulated,of which the availability and the performance are optimally suited.In this review,the explicit diversity of CVD diamond and the clarification of typical grades for applications,i.e.,from resplendent gem-grade to promising quantum-grade,were systematically summarized and discussed,according to the crystal quality and main consideration of ubiquitous nitrogen impurity content as well as major applications.Realizations of those,from quantum-grade with near-ideal crystal to electronic-grade having extremely low imperfections and then to optical,thermal as well as mechanical-grade needing controlled flaws and allowable impurities,would competently fulfill the multi-field application prospects with appropriate choice in terms of cost and quality.Exceptionally,wide range defects and impurities in the gem-grade diamond(only indicating single crystal),which are detrimental for technology applications,endows CVD crystals with fancy colors to challenge their natural counterparts.展开更多
基金the financial support by the National Natural Science Foundation of China (22371010, 21771017, and 51702009)the "Hundred Talents Program" of the Chinese Academy of Sciences, the Fundamental Research Funds for the Central Universities+1 种基金the Shenzhen Science and Technology Program (JCYJ20210324115412035, JCYJ2021-0324123202008, JCYJ20210 324122803009 and ZDSYS20210813095534001)the Guangdong Basic and Applied Basic Research Foundation (2021A1515110880)
文摘The use of redox-active organic electrode materials in energy storage is restricted due to their inferior solvent resistance,abysmal conductivity,and the resultant low practical capacity.To address these issues,a class of bipolar p-phenylenediimidazole-based small-molecule compounds are designed and fabricated.Theπ-conjugated backbone of these small molecules allows for electron delocalization on a big conjugation plane,endowing them with good conductivity and reaction reversibility.Furthermore,when the para-positions of phenylene are occupied by hydroxyl groups,as-formed intramolecular hydrogen bonds(N-H...O)between phenolic hydroxyl groups and the–NH groups of imidazole rings further enhance the structural planarity,resulting in higherπ-conjugation degree and better conductivity,and thus higher utilization of active sites and electrode capacity,proved by both experimental results and theoretical calculations.The optimized composite electrode DBNQ@rGO-45 shows a high specific capacity(∼308 mA h g^(−1)at 100 mA g^(−1))and a long cycling stability(112.9 mA h g^(−1)after 6000 cycles at 2000 mA g^(−1)).The significantly better electrochemical properties for hydroxyl group-containing compounds than those without hydroxyl groups attributed to intramolecular hydrogen bond-induced conjugation enhancement will inspire the structure design of organic electrodes for better energy storage.
基金supported by the National Key Research and Development Program(No.2019YFE03100200)the State Key Lab for Advanced Metals and Materials,the Fund of National Key Laboratory of Solid-State Microwave Devices and Circuits,the National Natural Science Foundation of China(No.52102034)the Or-ganized Research Fund of North China University of Tech-nology(No.2023YZZKY12).The authors are very grateful for the financial support of these institutions.
文摘This study focused on the investigation of the edge effect of diamond films deposited by microwave plasma chemical vapor de-position.Substrate bulge height△h is a factor that affects the edge effect,and it was used to simulate plasma and guide the diamond-film deposition experiments.Finite-element software COMSOL Multiphysics was used to construct a multiphysics(electromagnetic,plasma,and fluid heat transfer fields)coupling model based on electron collision reaction.Raman spectroscopy and scanning electron microscopy were performed to characterize the experimental growth and validate the model.The simulation results reflected the experimental trends observed.Plasma discharge at the edge of the substrate accelerated due to the increase in△h(△h=0-3 mm),and the values of electron density(n_(c)),molar concentration of H(C_(H)),and molar concentration of CH_(3)(C_(CH_(3)))doubled at the edge(for the special concave sample with△h=−1 mm,the active chemical groups exhibited a decreased molar concentration at the edge of the substrate).At=0-3 mm,a high diamond growth rate and a large diamond grain size were observed at the edge of the substrate,and their values increased with.The uniformity of film thickness decreased with.The Raman spectra of all samples revealed the first-order characteristic peak of dia-mond near 1332 cm^(−1).When△h=−1 mm,tensile stress occurred in all regions of the film.When△h=1-3 mm,all areas in the film ex-hibited compressive stress.
基金supported by the National Natural Science Foundation of China(Nos.51861165101,51822706,51777200)Beijing Natural Science Foundation(No.JQ19012)DNL Cooperation Fund,CAS(DNL201912)。
文摘Lithium-sulfur(Li-S)batteries have been recognized as one of the most promising candidates for nextgeneration portable electronic devices,owing to their extremely high energy density and low cost.However,the dissolution of lithium polysulfides(LiPSs)and consequent"shuttle effect"seriously hinder the practical deployment of Li-S batteries.Herein,multi-metal oxide nanorods named attapulgite are proposed as multifunctional ionic sieve to immobilize LiPSs and further promote the regulation of LiPSs.Attapulgite,consisting of Al,Mg,Fe,Si and O ions,possesses more polar sites to immobilize LiPSs in comparison with single metal oxides.In addition,the catalytic nature(Fe ions)of attapulgite avails the LiPSs conversion reaction,which is further confirmed by the linear sweep voltammetry and electrochemical impedance spectroscopy.Benefited from the synergistic effect of multi-metal oxide and conductive carbon,the Li-S battery with the modified separator delivers remarkable discharge capacities of 1059.4 mAh g-1 and 792.5 mAh g-1 for the first and 200th cycle at 0.5 C,respectively.The work presents an effective way to improve the electrochemical performance of Li-S batteries by employing attapulgite nanorods assisted separator surface engineering.
基金supported by the National Key Research and Development Plan (No. 2017YFB0404201)the National Science Foundation of China (Nos. 61774147, 61874108)
文摘Due to the remarkable growth rate compared to another growth methods for gallium nitride(GaN)growth,hydride vapor phase epitaxy(HVPE)is now the only method for mass product GaN substrates.In this review,commercial HVPE systems and the GaN crystals grown by them are demonstrated.This article also illustrates some innovative attempts to develop homebuilt HVPE systems.Finally,the prospects for the further development of HVPE for GaN crystal growth in the future are also discussed.
基金financially supported by the National Key Research and Development Program of China (No.2018YFB0406501)the European Union’s Horizon 2020 Research and Innovation Staff Exchange (RISE) Scheme (No. 734578)the Beijing Natural Science Foundation (No. 4192038)。
文摘Periodic nitrogen-doped homoepitaxial nano-multilayers were grown by microwave plasma chemical vapor deposition. The residual time of gases(such as CH4and N2) in the chamber was determined by optical emission spectroscopy to determine the nano-multilayer growth process, and thin, nanoscale nitrogen-doped layers were obtained. The highest toughness of 18.2 MPa·m^(1/2)under a Young’s modulus of1000 GPa is obtained when the single-layer thickness of periodic nitrogen-doped nano-multilayers is about 96 nm. The fracture toughness of periodic nitrogen-doped CVD layer is about 2.1 times that of the HPHT seed substrate. Alternating tensile and compressive stresses are derived from periodic nitrogen doping;hence, the fracture toughness is significantly improved. Single-crystal diamond with a high toughness demonstrates wide application prospects for high-pressure anvils and single-point diamond cutting tools.
文摘Gibberellin(GA)plays a major role in controlling Brassica rapa stalk development.As an essential negative regulator of GA signal transduction,DELLA proteins may exert significant effects on stalk development.However,the regulatory mechanisms underlying this regulation remain unclear.In this study,we report highly efficient and inheritable mutagenesis using the CRISPR/Cas9 gene editing system in BraPDS(phytoene desaturase)and BraRGL1(key DELLA protein)genes.We observed a loss-of-function mutation in BraRGL1 due to two amino acids in GRAS domain.The flower bud differentiation and bolting time of BraRGL1 mutants were significantly advanced.The expression of GA-regulatory protein(BraGASA6),flowering related genes(BraSOC1,BraLFY),expansion protein(BraEXPA11)and xyloglucan endotransferase(BraXTH3)genes was also significantly upregulated in these mutants.BraRGL1-overexpressing plants displayed the contrasting phenotypes.BraRGL1 mutants were more sensitive to GA signaling.BraRGL1 interacted with BraSOC1,and the interaction intensity decreased after GA3 treatment.In addition,BraRGL1 inhibited the transcription-activation ability of BraSOC1 for BraXTH3 and BraLFY genes,but the presence of GA3 enhanced the activation ability of BraSOC1,suggesting that the BraRGL1-BraSOC1 module regulates bolting and flowering of B.rapa through GA signal transduction.Thus,we hypothesized that BraRGL1 is degraded,and BraSOC1 is released in the presence of GA3,which promotes the expression of BraXTH3 and BraLFY,thereby inducing stalk development in B.rapa.Further,the BraRGL1-M mutant promoted the flower bud differentiation without affecting the stalk quality.Thus,BraRGL1 can serve as a valuable target for the molecular breeding of early maturing varieties.
基金supported by the National Natural Science Foundation of China(No.61906185,61876053)the Natural Science Foundation of Guangdong Province of China(No.2019A1515011705 and No.2021A1515011905)+2 种基金the Youth Innovation Promotion Association of CAS China(No.2020357)the Shenzhen Basic Research Foundation(No.JCYJ20210324115614039 and No.JCYJ20200109113441941)the Shenzhen Science and Technology Innovation Program(Grant No.KQTD20190929172835662).
文摘Handling emotions in human‐computer dialogues has emerged as a challenging task which requires artificial intelligence systems to generate emotional responses by jointly perceiving the emotion involved in the input posts and incorporating it into the gener-ation of semantically coherent and emotionally reasonable responses.However,most previous works generate emotional responses solely from input posts,which do not take full advantage of the training corpus and suffer from generating generic responses.In this study,we introduce a hierarchical semantic‐emotional memory module for emotional conversation generation(called HSEMEC),which can learn abstract semantic conver-sation patterns and emotional information from the large training corpus.The learnt semantic and emotional knowledge helps to enrich the post representation and assist the emotional conversation generation.Comprehensive experiments on a large real‐world conversation corpus show that HSEMEC can outperform the strong baselines on both automatic and manual evaluation.For reproducibility,we release the code and data publicly at:https://github.com/siat‐nlp/HSEMEC‐code‐data.
基金sponsored by National Key Research and Development Program of China(No.2019YFE03100200)National Natural Science Foundation of China(No.5210020483)+1 种基金Postdoc Research Foundation of Shunde Graduate School of University of Science and Technology Beijing(No.2020BH015)Fundamental Research Funds for the Central Universities(No.FRF-MP-20-48)。
文摘In this study,uniform diamond films with a diameter of 100 mm were deposited in a 15 kW/2.45 GHz ellipsoidal microwave plasma chemical vapour deposition system.A phenomenological model previously developed by our group was used to simulate the distribution of the electric strength and electron density of plasma.Results indicate that the electric field in the cavity includes multiple modes,i.e.TM_(02) and TM_(03).When the gas pressure exceeds 10 kPa,the electron density of plasma increases and plasma volume decreases.A T-shaped substrate was developed to achieve uniform temperature,and the substrate was suspended in air fromφ70 to 100 mm,thus eliminating vertical heat dissipation.An edge electric field was added to the system after the introduction of the T-shaped substrate.Moreover,the plasma volume in this case was greater than that in the central electric field but smaller than that in the periphery electric field of the TM_(02) mode.This indicates that the electric field above and below the edge benefits the plasma volume rather than the periphery electric field of the TM_(02) mode.The quality,uniformity and surface morphology of the deposited diamond films were primarily investigated to maintain substrate temperature uniformity.When employing the improved substrate,the thickness unevenness of theφ100 mm diamond film decreased from 22%to 7%.
基金the National Key Research and Development Program of China(No.2016YFE0133200)National Natural Science Foundation of China(No.52172037)+4 种基金European Union’s Horizon 2020 Research and Innovation Staff Exchange Scheme(No.734578)Post-doctor Research Foundation of Shunde Graduate School of University of Science and Technology Beijing(No.2021 BH006)Beijing Municipal Natural Science Foundation(Nos.2212036 and 4192038)Science and Technology Innovation Special Project of Foshan Government(Nos.BK20BE021 and BK21BE004)Special thanks to the nation-al high-level-university sponsored graduate program of China Scholarship Council(CSC),USTB-Monte Biance Joint R&D Center and joint-postdoc research program of Shunde Graduate School of USTB.
文摘Current electronic technology based on silicon is approaching its physical and scientific limits. Carbon-based devices have numer- ous advantages for next generation electronics (e.g., fast speed, low power consumption and simple process), that when combined with the unique nature of the versatile allotropes of carbon elements, are creating an electronics revolution. Carbon electronics are greatly advancing with new preparations and sophisticated designs. In this perspective, representatives with various dimensions, e.g., carbon nanotubes, graphene, bulk diamond, and their extraordinary performance, are reviewed. The associated state-of-the-art devices and composite hybrid all-carbon structures are also emphasized to reveal their potential in the electronics field. Advances in commercial production have improved the cost effi-ciency, material quality, and device design, accelerating the promise of carbon materials.
文摘With the deepening application of geographic information web services, as a significant part, geographic information directory service sets up a service transaction platform between the service providers and the service requestors, providing one-stop registration, access and management functions of geographic information web services, so it is very important to carry out the research on geographic information directory service. According to the domestic and overseas metadata standards, the service expression-oriented metadata information model for geographic information web service is established, and the discovery mechanism dominated by geographic information service registration and active discovery is realized accordingly. After that, overall design of directory service model is made, and finally the research results are integrated into the geographic information service software NewMapServer and deployment test is made under the Google Cloud Environment Google App Engine, providing a certain reference for sharing the Smart City construction achievements.
基金supported by the Yunnan Fundamental Research Projects(No.202301BC070001-001)funded by the Yunnan Provincial Department of Science and Technologythe Yunnan Provincial Science and Technology Plan Project(No.202005AF150045)+1 种基金the Jiangsu Province Industry-University-Research Cooperation Project(No.BY2022832)funded by the Jiangsu Provincial Department of Science and Technologythe National Natural Science Foundation of China(No.52275339).
文摘Different amounts of Fe(0.005,0.01,0.03,0.05,and 0.07 wt%)were added to SAC305 to study the shear behavior damage of Fe-doped SAC solder joints under thermal loading(170℃,holding time of 0,250,500,and 750 h).The results show that during isothermal aging at 170℃,the average shear force of all solder joints decreases with increasing aging time,while the average fracture energy first increases and then decreases,reaching a maximum at 500 h.Minor Fe doping could both increase shear forces and related fracture energy,with the optimum Fe doping amount being 0.03 wt%within the entire aging range.This is because the doping Fe reduces the undercooling of the SAC305 alloy,resulting in the microstructure refining of solder joints.This in turn causes the microstructure changing from network structure(SAC305 joint:eutectic network+β-Sn)to a single matrix structure(0.03Fe-doped SAC305 joint:β-Sn matrix+small compound particles).Specifically,Fe atoms can replace some Cu in Cu_(6)Sn_(5)(both inside the solder joint and at the interface),and then form(Cu,Fe)_(6)Sn_(5) compounds,resulting in an increase in the elastic modulus and nanohardness of the compounds.Moreover,the growth of Cu_(6)Sn_(5) and Cu_(3)Sn intermetallic compounds(IMC)layer are inhibited by Fe doping even after the aging time prolonging,and Fe aggregates near the interface compound to form FeSn_(2).This study is of great significance for controlling the growth of interfacial compounds,stabilizing the microstructures,and providing strengthening strategy for solder joint alloy design.
文摘Smart city is the development of digital city; as its main supporting technology, the digital city geo-spatial framework has to be upgraded to the temporal-spatial information infrastructure (TSII). first, this paper proposes the concept and basic framework of smart city and defines the concept of TSII - processes, integration, mining analysis, and share time-stamps geographic data - and the related policy, regulations and standards, technology, facilities, mechanism, and human resources. The framework has four components: the benchmark of time and space, temporal-spatial big data, the cloud service platform and the related supporting environment. Second, the temporal-spatial big data and cloud service platform are elaborated. finally, an application of TSII constructed by the Xicheng District Planning Bureau in Beijing is introduced, which provides a useful reference for the construction of smart city.
基金supported by grants from the National Natural Science Foundation of China(No.52242208).
文摘Antioxidant collagen hydrolysates refers to the peptides mixture with antioxidant properties identified from hydrolyzed collagen.Due to its specific structural,biological and physicochemical properties,collagen hydrolysates have been explored as a multifunctional antioxidant in the biomedical field.In this review,we summarize recent advances in antioxidant collagen hydrolysates development.Initially,the preparation process of antioxidant collagen hydrolysates is introduced,including the production and separation methods.Then the effects and the mechanisms of amino acid composition and collagen peptide structure on the antioxidant activity of collagen hydrolysates are reviewed.Finally,the applications of antioxidant collagen hydrolysates in biomedical domains are summarized,with critical discussions about the advantages,current limitations and challenges to be resolved in the future.
基金financially supported by the National Natural Science Foundation of China(51922081,51961135303,51932007,and U1705251)National Innovation and Entrepreneurship Training Program for College Students(S202110497007)。
文摘The construction of donor-acceptor(D-A)molecular structure is an attractive strategy to enhance the photocatalytic performance of polymeric semiconductors.Herein,dibenzothiophene(DBT)-4-carbaldehyde as the precursor is introduced into g-C_(3)N_(4)(TCN)prepared by two-step thermal polymerization to construct an intramolecular D-A type copolymer(TCN-DBT_(x)).DFT calculation and experimental results reveal that DBT plays the role of electron donor unit to modify g-C_(3)N_(4).The incorporation of DBT not only adjusts the band gap to improve reduction ability,but also induces an internal electric field with extendingπ-conjugated system for effective charge transfer.As a result,TCN-DBT_(x)exhibits much better photocatalytic performance with an optimal hydrogen production rate of 3334μmol h^(-1)g^(-1),which is 2.5 times that of TCN.This work provides a protocol for preparing high-performance g-C_(3)N_(4)-based photocatalysts toward various applications.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2016YFE0133200)the European Union’s Horizon 2020 Research and Innovation Staff Exchange Scheme(Grant No.734578)+6 种基金the Post-doctor Research Foundation of Shunde Graduate School of University of Science and Technology Beijing(Grant No.2021BH006)the National Natural Science Foundation of China(Grant No.52172037)the Beijing Municipal Natural Science Foundation(Grant Nos.2212036 and 4192038)the Fundamental Research Funds for the Central Universities(FRF-MP-20-49Z)the Science and Technology Innovation Special Project of Foshan Government(Grant Nos.BK20BE021 and BK21BE004)Special thanks to the Guangdong Basic and Applied Basic Research Foundation(Grant No.2021A1515110631)the national high-level-university sponsored graduate program of China Scholarship Council(CSC No.201806460089),USTB-Monte Biance Joint R&D Center.
文摘Chemical vapor deposited(CVD)diamond as a burgeoning multifunctional material with tailored quality and characteristics can be artificially synthesized and controlled for various applications.Correspondingly,the application-related“grade”concept associated with materials choice and design was gradually formulated,of which the availability and the performance are optimally suited.In this review,the explicit diversity of CVD diamond and the clarification of typical grades for applications,i.e.,from resplendent gem-grade to promising quantum-grade,were systematically summarized and discussed,according to the crystal quality and main consideration of ubiquitous nitrogen impurity content as well as major applications.Realizations of those,from quantum-grade with near-ideal crystal to electronic-grade having extremely low imperfections and then to optical,thermal as well as mechanical-grade needing controlled flaws and allowable impurities,would competently fulfill the multi-field application prospects with appropriate choice in terms of cost and quality.Exceptionally,wide range defects and impurities in the gem-grade diamond(only indicating single crystal),which are detrimental for technology applications,endows CVD crystals with fancy colors to challenge their natural counterparts.