Ammonia plays an essential role in human production and life as a raw material for chemical fertilizers.The nitrate electroreduction to ammonia reaction(NO_(3)RR)has garnered attention due to its advantages over the H...Ammonia plays an essential role in human production and life as a raw material for chemical fertilizers.The nitrate electroreduction to ammonia reaction(NO_(3)RR)has garnered attention due to its advantages over the Haber-Bosch process and electrochemical nitrogen reduction reaction.Therefore,it represents a promising approach to safeguard the ecological environment by enabling the cycling of nitrogen species.This review begins by discussing the theoretical insights of the NO_(3)RR.It then summarizes recent advances in catalyst design and construction strategies,including alloying,structure engineering,surface engineering,and heterostructure engineering.Finally,the challenges and prospects in this field are presented.This review aims to guide for enhancing the efficiency of electrocatalysts in the NO_(3)RR,and offers insights for converting NO_(3)-to NH_(3).展开更多
This article reports a new generation of Q460 multi-functional construction structural steel,which has high strength(yield strength larger than 460 MPa),excellent toughness(higher than 110 J/cm^(2) at-60 ℃),lower yie...This article reports a new generation of Q460 multi-functional construction structural steel,which has high strength(yield strength larger than 460 MPa),excellent toughness(higher than 110 J/cm^(2) at-60 ℃),lower yield ratio(lower than 0.8),good fire resistance(yield strength at 600 ℃ larger than two-thirds of its room-temperature yield strength)and better corrosion resistance.The eff ects of finish cooling temperature(FCT)on the microstructure and properties were studied by scanning electron microscopy(SEM),transmission electron microscopy(TEM),emission electron probe micro-analysis(EPMA),electron backscattering diff raction(EBSD),tensile tester,impact tester,periodic immersion cycle acceleration test and electrochemical experiment.The results show that the strength and toughness are simultaneously improved by decreasing the FCT due to more lath-like bainite with large number of dislocations,refined martensite/austenite(M/A)with higher carbon concentration and increased high angle boundaries.In addition,the fire resistance of the newly developed Q460 steel is obviously better than the conventional one,which is mainly due to non-recrystallized lath-like bainite with high dislocation density at elevated temperature.The corrosion resistance of the new Q460 steel is also improved due to the addition of Cu and Cr.展开更多
Exploiting advanced nanocomposites isochronally integrating outstanding thermal conductivity(TC)and electromagnetic interference shielding effectiveness(EMI SE)can boost the cutting-edge application of phase change ma...Exploiting advanced nanocomposites isochronally integrating outstanding thermal conductivity(TC)and electromagnetic interference shielding effectiveness(EMI SE)can boost the cutting-edge application of phase change materials.Here,we report a tiramisu-like composite(GMP),where the typical“crust-and-cheese”hierarchical structure is replicated by an innovative two-step bidirectional freezing assembly(BFA)and compressive densification.Hierarchical-aligned graphene array(G-GA)with ultralow thermal resistance is fabricated through 1st BFA and graphitization.During the 2nd BFA,the MXene-CNF crosslinking network with hydrogen-bond actions is used for encapsulating polyethylene glycol(PEG)onto the microlayers of the G-GA skeleton.Remarkably,the microlaminated GMP4 achieves a recorded TC of 34.05 W m^(-1) K^(-1),unprecedented EMI SE of 87.4 dB,and preferable enthalpy density of 179.4 J cm^(-3),along with leakage-free function,and eminent thermal durability.Furthermore,the GMP-loaded equipment is demonstrated for efficient microelectronics cooling and sustainable solar energy utilization.This work opens new avenues for multiscale designing multifunctional macro-composites,broadening the application prospects in advanced electronics and solar energy utilization systems.展开更多
The design quality of construction drawing of building structure is an important basis of engineering construction quality, which can fully reflect the design concept. Any problems existing in the design of constructi...The design quality of construction drawing of building structure is an important basis of engineering construction quality, which can fully reflect the design concept. Any problems existing in the design of construction drawing will affect the safety of building. At the same time, the design of construction drawing has certain technical content, which reflects the architects grasp of the scheme and the ability to apply technology. Therefore, in order to conscientiously implement the relevant regulations of national architectural design and improve the design quality of structural construction drawings, this paper analyzes the problems existing in the design of structural construction drawings of architectural engineering, and puts forward some improvement suggestions for reference by structural construction drawing designers.展开更多
The effects of concrete's time-variant elastic modulus,casting structural components,assembling temporary shoring framework system,and shock by operating construction equipment on dynamic behavior of the reinforce...The effects of concrete's time-variant elastic modulus,casting structural components,assembling temporary shoring framework system,and shock by operating construction equipment on dynamic behavior of the reinforced concrete frame structure during construction were investigated. The dynamic tests of an eight-storey reinforced concrete frame structure during full-scaled stages of the sixth storey construction cycle were carried out by ambient vibration. Natural frequencies,corresponding mode shapes and damping ratio were determined by power spectrum processing the tested signal data in frequency domain. The changes of frequencies,mode shapes and damping ratios at different construction stages were given. The results show that natural frequencies and modal damping ratios reach the maximum at stage of casting fresh concrete,especially for higher modes. Modal damping ratios at each construction stage are less than 5% of those during usage.展开更多
With the rapid development of China's economy and society, the development speed of industry is also accelerating. Before 1949, China was still an agricultural country, with little progress in industry. In just a ...With the rapid development of China's economy and society, the development speed of industry is also accelerating. Before 1949, China was still an agricultural country, with little progress in industry. In just a few decades, China's industry has made a qualitative leap, promoting China from an economically backward agricultural country into the world's largest industrial producer, and made remarkable achievements. The most direct manifestation of the development of industry is the establishment of a large number of factories, the factory will inevitably discharge a large amount of sewage, wastewater in the production process, resulting in water quality deterioration. These industrial wastewater contains a lot of lead, mercury and other harmful chemicals, and its emissions have also caused a certain degree of pollution to people's domestic water. If measures are not taken to purify water resources, it will harm people's health, especially for children, which can not be underestimated.展开更多
With the construction improvement of prefabricated building standards, the progress brought to society and the continuous improvement brought to industry, the technical level is constantly standardized, and the modeli...With the construction improvement of prefabricated building standards, the progress brought to society and the continuous improvement brought to industry, the technical level is constantly standardized, and the modeling and integration also meet the national requirements. In this way, the improvement of accuracy and quality will be more and more widely used in China, and prefabricated buildings will have a new world. In this process, enterprises need to pay more attention to prefabricated buildings, and combine with the current modern construction technology to fully grasp the technical points and control details, so as to effectively reduce the construction cost, reduce unnecessary waste of resources and shorten the construction period, improve the safety and reliability of buildings, and create a greener and diversified living environment. This paper makes an analysis.展开更多
The inherent teaching approach can no longer meet the demands of society.In this paper,current issues within the teaching landscape of architectural engineering technology in higher vocational colleges as well as the ...The inherent teaching approach can no longer meet the demands of society.In this paper,current issues within the teaching landscape of architectural engineering technology in higher vocational colleges as well as the policies and teaching demands that formed the basis of this model were analyzed.The study shows the importance of the implementation of the teaching model“promoting teaching and learning through competitions.”This model puts emphasis on the curriculum and teaching resources,while also integrating the teaching process and evaluation with competition.These efforts aim to drive education reform in order to better align with the objectives of vocational education personnel training,while also acting as a reference for similar courses.展开更多
To compensate for the imperfection of traditional bi-directional evolutionary structural optimization, material interpolation scheme and sensitivity filter functions are introduced. A suitable filter can overcome the ...To compensate for the imperfection of traditional bi-directional evolutionary structural optimization, material interpolation scheme and sensitivity filter functions are introduced. A suitable filter can overcome the checkerboard and mesh-dependency. And the historical information on accurate elemental sensitivity numbers are used to keep the objective function converging steadily. Apart from rational intervals of the relevant important parameters, the concept of distinguishing between active and non-active elements design is proposed, which can be widely used for improving the function and artistry of structures directly, especially for a one whose accurate size is not given. Furthermore, user-friendly software packages are developed to enhance its accessibility for practicing engineers and architects. And to reduce the time cost for large timeconsuming complex structure optimization, parallel computing is built-in in the MATLAB codes. The program is easy to use for engineers who may not be familiar with either FEA or structure optimization. And developers can make a deep research on the algorithm by changing the MATLAB codes. Several classical examples are given to show that the improved BESO method is superior for its handy and utility computer program software.展开更多
The construction of core-shell structure is an effective strategy for promoting the emission efficiency of upconversion nanocrystals(UCNCs). In this work, the UCNCs based on Nd-doping with a multilayer coreshell nanos...The construction of core-shell structure is an effective strategy for promoting the emission efficiency of upconversion nanocrystals(UCNCs). In this work, the UCNCs based on Nd-doping with a multilayer coreshell nanostructure are fabricated toward achieving efficient upconversion for 808 nm excitation, which have great potential for optical applications, especially photobiological applications.展开更多
The spiral assembly steel structure, a newly developed retaining wall for the rapid excavation of small-sized foundation pits in unsaturated soil, is presented. This new type of retaining structure is prefabricated in...The spiral assembly steel structure, a newly developed retaining wall for the rapid excavation of small-sized foundation pits in unsaturated soil, is presented. This new type of retaining structure is prefabricated in the factory and is assembled on site in the excavation of a pit. This retaining structure is composed of several prefabricated steel structural units, in which the adjacent steel structural units are joined with connectors. Each steel structural unit has one steel pipe in the radial direction and is welded to a single piece of steel plate. After full installation in situ, the retaining structure becomes a cylindrical steel structure. With the protection afforded by this new type of retaining structure, excavation work can be completed within 24 h to a depth up to 5 m. In order to verify the reliability and effectiveness of this new retaining structure, field construction tests were conducted in Beijing, China. The test construction was monitored. The monitoring program included measuring stress in the structure, lateral earth pressure, and lateral deformation of the surrounding soil. The monitoring data from the field test were compared with the theoretical results. The results show that the proposed new structure is reliable and effective.展开更多
During the construction of prefabricated building engineering, the quality of prefabricated building engineering is often affected by various internal and external factors which affect the sustainable development of t...During the construction of prefabricated building engineering, the quality of prefabricated building engineering is often affected by various internal and external factors which affect the sustainable development of the construction industry. With the advancement of Science and technology, the perfection of industrial chain and the improvement and innovation of architectural design concept, combined with the advantages of steel structure " light, convenient, smart and fast ", the development of fabricated steel structure in residential area is worth popularizing. Therefore, we should make great efforts to popularize the assembled steel structure housing in the urban construction level and promote the housing industrialization development, so as to realize the common development of our countrys housing industrys economic and social benefits.展开更多
Hard carbon(HC)anodes in sodium-ion batteries(SIBs)are prized for their high capacity,durability,costefficiency,environmental sustainability,and safety.The metallic ash elements in HCs inevitably affect the overall pe...Hard carbon(HC)anodes in sodium-ion batteries(SIBs)are prized for their high capacity,durability,costefficiency,environmental sustainability,and safety.The metallic ash elements in HCs inevitably affect the overall performance of SIBs,however,the unclear role of metallic ash elements during carbonization and the electrochemical sodium storage process presents challenges for advancing HC design concepts.In this review,the traditional role of metallic ash element realized in the past and the deep understanding by a new sight from the view of intrinsic types in precursor matrix are initially introduced.Subsequently,the effect of catalyzing graphitization degree,constructing pore structure,tuning SEI formation and tailoring defects of the HCs regulated by extrinsic factors introduced through experimental conditions in recent years are comprehensively summarized.Additionally,future development prospects and perspectives on the research about metallic ash element in HC are also briefly outlined.It is believed that this review can deliver noteworthy viewpoints by introducing metallic ash elements,for the continued development of adjusting the microstructure of HCs at the nanoscale to actualize highperformance SIBs.展开更多
As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security ...As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security threats to blockchain ecosystems.Although numerous detection techniques have been proposed,existing methods suffer from significant limitations,such as class imbalance and insufficient modeling of transaction-related semantic features.To address these challenges,this paper proposes an oversampling-based detection framework for Ponzi smart contracts.We enhance the Adaptive Synthetic Sampling(ADASYN)algorithm by incorporating sample proximity to decision boundaries and ensuring realistic sample distributions.This enhancement facilitates the generation of high-quality minority class samples and effectively mitigates class imbalance.In addition,we design a Contract Transaction Graph(CTG)construction algorithm to preserve key transactional semantics through feature extraction from contract code.A graph neural network(GNN)is then applied for classification.This study employs a publicly available dataset from the XBlock platform,consisting of 318 verified Ponzi contracts and 6498 benign contracts.Sourced from real Ethereum deployments,the dataset reflects diverse application scenarios and captures the varied characteristics of Ponzi schemes.Experimental results demonstrate that our approach achieves an accuracy of 96%,a recall of 92%,and an F1-score of 94%in detecting Ponzi contracts,outperforming state-of-the-art methods.展开更多
This paper Investigates Hamiltonian realization of time-varying nonlinear （TVN） systems, and proposes a number of new methods for the problem. It is shown that every smooth TVN system can be expressed as a generaliz...This paper Investigates Hamiltonian realization of time-varying nonlinear （TVN） systems, and proposes a number of new methods for the problem. It is shown that every smooth TVN system can be expressed as a generalized Hamiltonian system if the origin is the equilibrium of the system. If the Jacooian matrix of a TVN system is nonsingular, the system has a generalized Hamiltonian realization whose structural matrix and Hamiltonian function are given explicitly. For the case that the Jacobian matrix is sin- gular; this paper provides a constructive decomposition method, and then proves that a TVN system has a generalized Hamiltonian realization if its Jacobian matrix has a non- singular main diagonal block. Furthermore, some sufficient （necessary and sufficient） conditions for dissipative Hamiltonian realization of TVN systems are also presented in this paper.展开更多
An isospectral problem with four potentials is discussed. The corresponding hierarchy of nonlinearevolution equations is derived. It is shown that the AKNS, Levi, D-AKNS hierarchies and a new oneare reductions of the ...An isospectral problem with four potentials is discussed. The corresponding hierarchy of nonlinearevolution equations is derived. It is shown that the AKNS, Levi, D-AKNS hierarchies and a new oneare reductions of the above hierarchy. In each case the relevant Hamiltonian form is established bymaking use of the trase identity.展开更多
Carbon-based electromagnetic wave absorbing materials(absorbers)adhered with metallic sulfide nanoparticles of good electrical conductivity attract increasing researchers’attention.In this study,on the basis of carbo...Carbon-based electromagnetic wave absorbing materials(absorbers)adhered with metallic sulfide nanoparticles of good electrical conductivity attract increasing researchers’attention.In this study,on the basis of carbon fiber(C_(f))@Fe_(3)O_(4) nanocomposites obtained by the electrostatic spinning and reflow method,C_(f)@FeS_(2)nanocomposite was successfully prepared during a further hydrothermal process.The products exhibit excellent electromagnetic wave absorption performances with a minimum reflection loss(RLmin)of-54.11 dB at 2.13 mm matching thickness.At the same time,the optimal effective absorption bandwidth(EAB)value of 6.04 GHz at a thickness of 1.98 mm covers the whole Ku band,suggesting its excellent electromagnetic wave absorption performances.In addition,the interlaced network structure constructed by carbon fiber,outstanding conductivity of FeS_(2)nanoparticles,and interfacial polarization from hetero-structure play significant parts in enhancing the electromagnetic parameters and absorption performances.All these results suggest that the C_(f)@FeS_(2)nanocomposites can be taken as a new electromagnetic wave-absorbing material under their low density,simple craft,and strong absorption characteristics.展开更多
Antifreeze protein(AFP)can inhibit the growth of ice crystals to protect organisms from freezing damage,and demonstrates broad application prospects in food industry.Antifreeze peptides(AFPP)are specifi c peptides wit...Antifreeze protein(AFP)can inhibit the growth of ice crystals to protect organisms from freezing damage,and demonstrates broad application prospects in food industry.Antifreeze peptides(AFPP)are specifi c peptides with functional domains showing antifreeze activity in AFP.Bioinformatics-based molecular simulation technology can more accurately explain the properties and mechanisms of biological macromolecules.Therefore,the binding stability of antifreeze peptides and antifreeze proteins(AFP(P))to ice and the molecular-scale growth kinetics of ice were analyzed by molecular simulation,which can make up for the limitations of experimental technology.This review concludes the molecular simulation-based research in the inhibition’s study of AFP(P)on ice growth,including sequence prediction,structure construction,molecular docking and molecular dynamics(MD)studies of AFP(P)on ice applications in growth inhibition.Finally,the review prospects the future direction of designing new antifreeze biomimetic materials through molecular simulation and machine learning.The information presented in this paper will help enrich our understanding of AFPP.展开更多
Lignocellulose is an ideal precursor for supercapacitor electrodes due to its diverse structures and abundant availability.For supercapacitors,particularly electric double-layer capacitors(EDLCs),pore structure is cri...Lignocellulose is an ideal precursor for supercapacitor electrodes due to its diverse structures and abundant availability.For supercapacitors,particularly electric double-layer capacitors(EDLCs),pore structure is critical.This review summarizes advances in lignocellulose-derived hierarchical porous carbon(LHPC)for supercapacitors,focusing on pore structure and future research directions.We discuss how pore structure influences supercapacitor performance,the activation methods for creating pores in LHPC,and review studies on optimizing pore structure for high-performance supercapacitors.Hierarchical porous carbon should feature a sufficient micropore surface area along with suitable mesoporous and macroporous surfaces to enhance rate performance while maintaining capacitance.This review is expected to actively advance the selection of lignocellulosic precursors and the development of optimized pore structure models,with the ultimate goal of enabling efficient production of lignocellulose-derived hierarchical porous carbon electrodes with superior properties.展开更多
Semiconductor based photocatalysis that harvests renewable solar energy to produce green hydrogen has attracted widespread attention[1],known for its environmental friendliness,low opera-tional costs,and scalability.E...Semiconductor based photocatalysis that harvests renewable solar energy to produce green hydrogen has attracted widespread attention[1],known for its environmental friendliness,low opera-tional costs,and scalability.Extensive experimental and theoretical explorations have significantly advanced the development of pho-tocatalysts for overall water splitting at laboratory scale[2],by band structure engineering[3],heterostructure construction[4],active site design[5],and even micro-/macro-texture modulation[6,7].Preliminary demonstration and verification of its large-scale application have been accomplished using SrTiO_(3) as photocatalyst[8].However,this technology yet faces the great challenges in practical application,with solar-to-hydrogen conversion efficiency still lower than 2%,suffering from the thermodynamically and kinetically constrained water splitting reactions[9].Although some well documented strategies(e.g.,light concentration,exter-nal heat,and concentrated electrolytes)could overcome these pho-tocatalytic limitations to some extent[10],the introduced harsh reaction conditions would significantly compromise the durability of photocatalysts[11].For example,to realize the practical applica-tion of photocatalytic recycling and upgrading of plastic wastes into solar hydrogen,strong alkaline solutions containing mono-meric constituents should serve as feedstocks for photo-reforming[12],with photocatalysts exposed to the harsh alkaline condition and then suffering from degradation and inactivation.展开更多
基金supported by the National Natural Science Foundation of China(22202151)Fundamental Research Program of Shanxi Province(202203021212243)。
文摘Ammonia plays an essential role in human production and life as a raw material for chemical fertilizers.The nitrate electroreduction to ammonia reaction(NO_(3)RR)has garnered attention due to its advantages over the Haber-Bosch process and electrochemical nitrogen reduction reaction.Therefore,it represents a promising approach to safeguard the ecological environment by enabling the cycling of nitrogen species.This review begins by discussing the theoretical insights of the NO_(3)RR.It then summarizes recent advances in catalyst design and construction strategies,including alloying,structure engineering,surface engineering,and heterostructure engineering.Finally,the challenges and prospects in this field are presented.This review aims to guide for enhancing the efficiency of electrocatalysts in the NO_(3)RR,and offers insights for converting NO_(3)-to NH_(3).
基金financially supported by the Key Research and Development Program of Hebei Province of China(Grant No.18211019D)the"333 Talent Project"of Hebei(Grant No.A201803007)the Technical Development Program between HBIS Company Limited and NEU(Contract No.2019040200044)。
文摘This article reports a new generation of Q460 multi-functional construction structural steel,which has high strength(yield strength larger than 460 MPa),excellent toughness(higher than 110 J/cm^(2) at-60 ℃),lower yield ratio(lower than 0.8),good fire resistance(yield strength at 600 ℃ larger than two-thirds of its room-temperature yield strength)and better corrosion resistance.The eff ects of finish cooling temperature(FCT)on the microstructure and properties were studied by scanning electron microscopy(SEM),transmission electron microscopy(TEM),emission electron probe micro-analysis(EPMA),electron backscattering diff raction(EBSD),tensile tester,impact tester,periodic immersion cycle acceleration test and electrochemical experiment.The results show that the strength and toughness are simultaneously improved by decreasing the FCT due to more lath-like bainite with large number of dislocations,refined martensite/austenite(M/A)with higher carbon concentration and increased high angle boundaries.In addition,the fire resistance of the newly developed Q460 steel is obviously better than the conventional one,which is mainly due to non-recrystallized lath-like bainite with high dislocation density at elevated temperature.The corrosion resistance of the new Q460 steel is also improved due to the addition of Cu and Cr.
基金support from the National Natural Science Foundation of China(No.21878218)the Tianjin Research Innovation Project for Postgraduate Students(No.2023KJ262)+2 种基金the State Grid Corporation of China’s Research Program(No.5419-202019385A)the Fundamental Research Funds for the Central Universities(No.92320006)the Tianjin Key Science and Technology Program(No.18ZXSZSF00030)。
文摘Exploiting advanced nanocomposites isochronally integrating outstanding thermal conductivity(TC)and electromagnetic interference shielding effectiveness(EMI SE)can boost the cutting-edge application of phase change materials.Here,we report a tiramisu-like composite(GMP),where the typical“crust-and-cheese”hierarchical structure is replicated by an innovative two-step bidirectional freezing assembly(BFA)and compressive densification.Hierarchical-aligned graphene array(G-GA)with ultralow thermal resistance is fabricated through 1st BFA and graphitization.During the 2nd BFA,the MXene-CNF crosslinking network with hydrogen-bond actions is used for encapsulating polyethylene glycol(PEG)onto the microlayers of the G-GA skeleton.Remarkably,the microlaminated GMP4 achieves a recorded TC of 34.05 W m^(-1) K^(-1),unprecedented EMI SE of 87.4 dB,and preferable enthalpy density of 179.4 J cm^(-3),along with leakage-free function,and eminent thermal durability.Furthermore,the GMP-loaded equipment is demonstrated for efficient microelectronics cooling and sustainable solar energy utilization.This work opens new avenues for multiscale designing multifunctional macro-composites,broadening the application prospects in advanced electronics and solar energy utilization systems.
文摘The design quality of construction drawing of building structure is an important basis of engineering construction quality, which can fully reflect the design concept. Any problems existing in the design of construction drawing will affect the safety of building. At the same time, the design of construction drawing has certain technical content, which reflects the architects grasp of the scheme and the ability to apply technology. Therefore, in order to conscientiously implement the relevant regulations of national architectural design and improve the design quality of structural construction drawings, this paper analyzes the problems existing in the design of structural construction drawings of architectural engineering, and puts forward some improvement suggestions for reference by structural construction drawing designers.
基金Project(50678064) supported by the National Natural Science Foundation of China
文摘The effects of concrete's time-variant elastic modulus,casting structural components,assembling temporary shoring framework system,and shock by operating construction equipment on dynamic behavior of the reinforced concrete frame structure during construction were investigated. The dynamic tests of an eight-storey reinforced concrete frame structure during full-scaled stages of the sixth storey construction cycle were carried out by ambient vibration. Natural frequencies,corresponding mode shapes and damping ratio were determined by power spectrum processing the tested signal data in frequency domain. The changes of frequencies,mode shapes and damping ratios at different construction stages were given. The results show that natural frequencies and modal damping ratios reach the maximum at stage of casting fresh concrete,especially for higher modes. Modal damping ratios at each construction stage are less than 5% of those during usage.
文摘With the rapid development of China's economy and society, the development speed of industry is also accelerating. Before 1949, China was still an agricultural country, with little progress in industry. In just a few decades, China's industry has made a qualitative leap, promoting China from an economically backward agricultural country into the world's largest industrial producer, and made remarkable achievements. The most direct manifestation of the development of industry is the establishment of a large number of factories, the factory will inevitably discharge a large amount of sewage, wastewater in the production process, resulting in water quality deterioration. These industrial wastewater contains a lot of lead, mercury and other harmful chemicals, and its emissions have also caused a certain degree of pollution to people's domestic water. If measures are not taken to purify water resources, it will harm people's health, especially for children, which can not be underestimated.
文摘With the construction improvement of prefabricated building standards, the progress brought to society and the continuous improvement brought to industry, the technical level is constantly standardized, and the modeling and integration also meet the national requirements. In this way, the improvement of accuracy and quality will be more and more widely used in China, and prefabricated buildings will have a new world. In this process, enterprises need to pay more attention to prefabricated buildings, and combine with the current modern construction technology to fully grasp the technical points and control details, so as to effectively reduce the construction cost, reduce unnecessary waste of resources and shorten the construction period, improve the safety and reliability of buildings, and create a greener and diversified living environment. This paper makes an analysis.
文摘The inherent teaching approach can no longer meet the demands of society.In this paper,current issues within the teaching landscape of architectural engineering technology in higher vocational colleges as well as the policies and teaching demands that formed the basis of this model were analyzed.The study shows the importance of the implementation of the teaching model“promoting teaching and learning through competitions.”This model puts emphasis on the curriculum and teaching resources,while also integrating the teaching process and evaluation with competition.These efforts aim to drive education reform in order to better align with the objectives of vocational education personnel training,while also acting as a reference for similar courses.
基金supported by the National Natural Science Foundation of China(No.51078311)
文摘To compensate for the imperfection of traditional bi-directional evolutionary structural optimization, material interpolation scheme and sensitivity filter functions are introduced. A suitable filter can overcome the checkerboard and mesh-dependency. And the historical information on accurate elemental sensitivity numbers are used to keep the objective function converging steadily. Apart from rational intervals of the relevant important parameters, the concept of distinguishing between active and non-active elements design is proposed, which can be widely used for improving the function and artistry of structures directly, especially for a one whose accurate size is not given. Furthermore, user-friendly software packages are developed to enhance its accessibility for practicing engineers and architects. And to reduce the time cost for large timeconsuming complex structure optimization, parallel computing is built-in in the MATLAB codes. The program is easy to use for engineers who may not be familiar with either FEA or structure optimization. And developers can make a deep research on the algorithm by changing the MATLAB codes. Several classical examples are given to show that the improved BESO method is superior for its handy and utility computer program software.
基金financially supported in part by National Key R&D Program of China (Nos.2020YFA0406103,2017YFA0207301),NSFC (Nos.21725102,91961106,U1832156,22075267)Science and Technological Fund of Anhui Province for Outstanding Youth (No.2008085J05)+3 种基金Youth Innovation Promotion Association of CAS (No.2019444)Young Elite Scientist Sponsorship Program by CAST,China Postdoctoral Science Foundation (Nos.BH2340000099,BH2340000138)Users with Excellence Program of Hefei Science Center CAS (No.2020HSC-UE003)support from USTC Center for Micro- and Nanoscale Research and Fabrication。
文摘The construction of core-shell structure is an effective strategy for promoting the emission efficiency of upconversion nanocrystals(UCNCs). In this work, the UCNCs based on Nd-doping with a multilayer coreshell nanostructure are fabricated toward achieving efficient upconversion for 808 nm excitation, which have great potential for optical applications, especially photobiological applications.
基金Project(41202220)supported by the National Natural Science Foundation of ChinaProject(20120022120003)supported by the Research Fund for the Doctoral Program of Higher Education,China+1 种基金Project(2652012065)supported by the Fundamental Research Funds for the Central Universities of ChinaProject(2013006)supported by the Research Fund for Key Laboratory on Deep Geo Drilling Technology,Ministry of Land and Resources,China
文摘The spiral assembly steel structure, a newly developed retaining wall for the rapid excavation of small-sized foundation pits in unsaturated soil, is presented. This new type of retaining structure is prefabricated in the factory and is assembled on site in the excavation of a pit. This retaining structure is composed of several prefabricated steel structural units, in which the adjacent steel structural units are joined with connectors. Each steel structural unit has one steel pipe in the radial direction and is welded to a single piece of steel plate. After full installation in situ, the retaining structure becomes a cylindrical steel structure. With the protection afforded by this new type of retaining structure, excavation work can be completed within 24 h to a depth up to 5 m. In order to verify the reliability and effectiveness of this new retaining structure, field construction tests were conducted in Beijing, China. The test construction was monitored. The monitoring program included measuring stress in the structure, lateral earth pressure, and lateral deformation of the surrounding soil. The monitoring data from the field test were compared with the theoretical results. The results show that the proposed new structure is reliable and effective.
文摘During the construction of prefabricated building engineering, the quality of prefabricated building engineering is often affected by various internal and external factors which affect the sustainable development of the construction industry. With the advancement of Science and technology, the perfection of industrial chain and the improvement and innovation of architectural design concept, combined with the advantages of steel structure " light, convenient, smart and fast ", the development of fabricated steel structure in residential area is worth popularizing. Therefore, we should make great efforts to popularize the assembled steel structure housing in the urban construction level and promote the housing industrialization development, so as to realize the common development of our countrys housing industrys economic and social benefits.
基金supported by the National Natural Science Foundation of China(52402302,52250710680)High-end Foreign Experts Recruitment Plan of China(G2023016009L)+3 种基金Zhejiang Provincial Natural Science Foundation of China(LQ24E020001)Key Research and Development Program of Zhejiang Province(2024C01057,2023C01232)Science and Technology Plan Project of Wenzhou Municipality(ZG2022032)The Natural Science Foundation of Changsha(kq2402017).
文摘Hard carbon(HC)anodes in sodium-ion batteries(SIBs)are prized for their high capacity,durability,costefficiency,environmental sustainability,and safety.The metallic ash elements in HCs inevitably affect the overall performance of SIBs,however,the unclear role of metallic ash elements during carbonization and the electrochemical sodium storage process presents challenges for advancing HC design concepts.In this review,the traditional role of metallic ash element realized in the past and the deep understanding by a new sight from the view of intrinsic types in precursor matrix are initially introduced.Subsequently,the effect of catalyzing graphitization degree,constructing pore structure,tuning SEI formation and tailoring defects of the HCs regulated by extrinsic factors introduced through experimental conditions in recent years are comprehensively summarized.Additionally,future development prospects and perspectives on the research about metallic ash element in HC are also briefly outlined.It is believed that this review can deliver noteworthy viewpoints by introducing metallic ash elements,for the continued development of adjusting the microstructure of HCs at the nanoscale to actualize highperformance SIBs.
基金supported by the Key Project of Joint Fund of the National Natural Science Foundation of China“Research on Key Technologies and Demonstration Applications for Trusted and Secure Data Circulation and Trading”(U24A20241)the National Natural Science Foundation of China“Research on Trusted Theories and Key Technologies of Data Security Trading Based on Blockchain”(62202118)+4 种基金the Major Scientific and Technological Special Project of Guizhou Province([2024]014)Scientific and Technological Research Projects from the Guizhou Education Department(Qian jiao ji[2023]003)the Hundred-Level Innovative Talent Project of the Guizhou Provincial Science and Technology Department(Qiankehe Platform Talent-GCC[2023]018)the Major Project of Guizhou Province“Research and Application of Key Technologies for Trusted Large Models Oriented to Public Big Data”(Qiankehe Major Project[2024]003)the Guizhou Province Computational Power Network Security Protection Science and Technology Innovation Talent Team(Qiankehe Talent CXTD[2025]029).
文摘As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security threats to blockchain ecosystems.Although numerous detection techniques have been proposed,existing methods suffer from significant limitations,such as class imbalance and insufficient modeling of transaction-related semantic features.To address these challenges,this paper proposes an oversampling-based detection framework for Ponzi smart contracts.We enhance the Adaptive Synthetic Sampling(ADASYN)algorithm by incorporating sample proximity to decision boundaries and ensuring realistic sample distributions.This enhancement facilitates the generation of high-quality minority class samples and effectively mitigates class imbalance.In addition,we design a Contract Transaction Graph(CTG)construction algorithm to preserve key transactional semantics through feature extraction from contract code.A graph neural network(GNN)is then applied for classification.This study employs a publicly available dataset from the XBlock platform,consisting of 318 verified Ponzi contracts and 6498 benign contracts.Sourced from real Ethereum deployments,the dataset reflects diverse application scenarios and captures the varied characteristics of Ponzi schemes.Experimental results demonstrate that our approach achieves an accuracy of 96%,a recall of 92%,and an F1-score of 94%in detecting Ponzi contracts,outperforming state-of-the-art methods.
基金Supported by the National Natural Science Foundation of China (Grant No. 60474001)the Research Fund of the Doctoral Program of ChineseHigher Education (Grant No. 20040422059)the Natural Science Foundation of Shandong Province (Grant No. Y2006G10)
文摘This paper Investigates Hamiltonian realization of time-varying nonlinear （TVN） systems, and proposes a number of new methods for the problem. It is shown that every smooth TVN system can be expressed as a generalized Hamiltonian system if the origin is the equilibrium of the system. If the Jacooian matrix of a TVN system is nonsingular, the system has a generalized Hamiltonian realization whose structural matrix and Hamiltonian function are given explicitly. For the case that the Jacobian matrix is sin- gular; this paper provides a constructive decomposition method, and then proves that a TVN system has a generalized Hamiltonian realization if its Jacobian matrix has a non- singular main diagonal block. Furthermore, some sufficient （necessary and sufficient） conditions for dissipative Hamiltonian realization of TVN systems are also presented in this paper.
基金The project supported by National Natural Science Foundation Committeethrough Nankai Institute of Mathematics
文摘An isospectral problem with four potentials is discussed. The corresponding hierarchy of nonlinearevolution equations is derived. It is shown that the AKNS, Levi, D-AKNS hierarchies and a new oneare reductions of the above hierarchy. In each case the relevant Hamiltonian form is established bymaking use of the trase identity.
基金The work reported here was supported by the National Natural Science Foundation of China(Nos.52072196,52002199,52002200,and 52102106)the Major Basic Research Program of Natural Science Foundation of Shandong Province(No.ZR2020ZD09)+2 种基金the Natural Science Foundation of Shandong Province(Nos.ZR2019BEM042 and ZR2020QE063)the Innovation and Technology Program of Shandong Province(No.2020KJA004)the Taishan Scholars Program of Shandong Province(No.ts201511034).We express our grateful thanks to them for their financial support.
文摘Carbon-based electromagnetic wave absorbing materials(absorbers)adhered with metallic sulfide nanoparticles of good electrical conductivity attract increasing researchers’attention.In this study,on the basis of carbon fiber(C_(f))@Fe_(3)O_(4) nanocomposites obtained by the electrostatic spinning and reflow method,C_(f)@FeS_(2)nanocomposite was successfully prepared during a further hydrothermal process.The products exhibit excellent electromagnetic wave absorption performances with a minimum reflection loss(RLmin)of-54.11 dB at 2.13 mm matching thickness.At the same time,the optimal effective absorption bandwidth(EAB)value of 6.04 GHz at a thickness of 1.98 mm covers the whole Ku band,suggesting its excellent electromagnetic wave absorption performances.In addition,the interlaced network structure constructed by carbon fiber,outstanding conductivity of FeS_(2)nanoparticles,and interfacial polarization from hetero-structure play significant parts in enhancing the electromagnetic parameters and absorption performances.All these results suggest that the C_(f)@FeS_(2)nanocomposites can be taken as a new electromagnetic wave-absorbing material under their low density,simple craft,and strong absorption characteristics.
基金This work was supported by Natural Science Foundation of China(U1905202)Fujian Major Project of Provincial Science&Technology Hall of China(2020NZ010008)Xiamen Ocean and Fishery Development Special Fund Project(21CZP006HJ04).
文摘Antifreeze protein(AFP)can inhibit the growth of ice crystals to protect organisms from freezing damage,and demonstrates broad application prospects in food industry.Antifreeze peptides(AFPP)are specifi c peptides with functional domains showing antifreeze activity in AFP.Bioinformatics-based molecular simulation technology can more accurately explain the properties and mechanisms of biological macromolecules.Therefore,the binding stability of antifreeze peptides and antifreeze proteins(AFP(P))to ice and the molecular-scale growth kinetics of ice were analyzed by molecular simulation,which can make up for the limitations of experimental technology.This review concludes the molecular simulation-based research in the inhibition’s study of AFP(P)on ice growth,including sequence prediction,structure construction,molecular docking and molecular dynamics(MD)studies of AFP(P)on ice applications in growth inhibition.Finally,the review prospects the future direction of designing new antifreeze biomimetic materials through molecular simulation and machine learning.The information presented in this paper will help enrich our understanding of AFPP.
基金financial support for this research from the National Key Research Development Program of China(No.2021YFB3800300)Shanghai Pujiang Programme(No.23PJD045)the Shanghai Science and Technology Committee(No.24CL2900600).
文摘Lignocellulose is an ideal precursor for supercapacitor electrodes due to its diverse structures and abundant availability.For supercapacitors,particularly electric double-layer capacitors(EDLCs),pore structure is critical.This review summarizes advances in lignocellulose-derived hierarchical porous carbon(LHPC)for supercapacitors,focusing on pore structure and future research directions.We discuss how pore structure influences supercapacitor performance,the activation methods for creating pores in LHPC,and review studies on optimizing pore structure for high-performance supercapacitors.Hierarchical porous carbon should feature a sufficient micropore surface area along with suitable mesoporous and macroporous surfaces to enhance rate performance while maintaining capacitance.This review is expected to actively advance the selection of lignocellulosic precursors and the development of optimized pore structure models,with the ultimate goal of enabling efficient production of lignocellulose-derived hierarchical porous carbon electrodes with superior properties.
基金supported by the National Natural Science Foun-dation of China(22432003,52225606,and 523B2070).
文摘Semiconductor based photocatalysis that harvests renewable solar energy to produce green hydrogen has attracted widespread attention[1],known for its environmental friendliness,low opera-tional costs,and scalability.Extensive experimental and theoretical explorations have significantly advanced the development of pho-tocatalysts for overall water splitting at laboratory scale[2],by band structure engineering[3],heterostructure construction[4],active site design[5],and even micro-/macro-texture modulation[6,7].Preliminary demonstration and verification of its large-scale application have been accomplished using SrTiO_(3) as photocatalyst[8].However,this technology yet faces the great challenges in practical application,with solar-to-hydrogen conversion efficiency still lower than 2%,suffering from the thermodynamically and kinetically constrained water splitting reactions[9].Although some well documented strategies(e.g.,light concentration,exter-nal heat,and concentrated electrolytes)could overcome these pho-tocatalytic limitations to some extent[10],the introduced harsh reaction conditions would significantly compromise the durability of photocatalysts[11].For example,to realize the practical applica-tion of photocatalytic recycling and upgrading of plastic wastes into solar hydrogen,strong alkaline solutions containing mono-meric constituents should serve as feedstocks for photo-reforming[12],with photocatalysts exposed to the harsh alkaline condition and then suffering from degradation and inactivation.
