Conventional electronics is planar, hard, and rigid due to the intrinsic brittle nature of inorganic semiconductor materials （e.g., silicon and gallium arsenide）. The modern electronic technology has typically been ...Conventional electronics is planar, hard, and rigid due to the intrinsic brittle nature of inorganic semiconductor materials （e.g., silicon and gallium arsenide）. The modern electronic technology has typically been concerned with large or small but durable and long-lasting electronics. Recently developed materials and mechanics concepts yield unconventional electronics with unique characteristics （e.g., deformable, degradable, etc.）.展开更多
Ceramic materials were investigated as thermal barrier coatings and electrolytes. Electrophoretic deposition（EPD） and physical vapor deposition（PVD） were employed to fabricate samples, and the mechanical propertie...Ceramic materials were investigated as thermal barrier coatings and electrolytes. Electrophoretic deposition（EPD） and physical vapor deposition（PVD） were employed to fabricate samples, and the mechanical properties and microstructure were examined by nanoindentation and microscopy, respectively. Yttria-stabilized zirconia/alumina（YSZ/Al2O3） composite coatings, a candidate for thermal barrier coatings, yield a kinky, rather than smooth, load–displacement curve. Scanning electron microscope（SEM） examination reveals that the kinky curve is because of the porous microstructure and cracks are caused by the compression of the indenter. Li0.34La0.51 Ti O2.94（LLTO） on Si/Sr Ru O3（Si/SRO） substrates, an ionic conductor in nature, demonstrates electronic performance. Although SEM images show a continuous and smooth microstructure, a close examination of the microstructure by transmission electron microscopy（TEM） reveals that the observed spikes indicate electronic performance. Therefore, we can conclude that ceramic coatings could serve multiple purposes but their properties are microstructure-dependent.展开更多
Ab initio calculations are performed to investigate the structural stability, electronic structure and mechanical properties of rubidium metal hydrides RbMH4（M = B, Al, Ga） for five different crystal structures, nam...Ab initio calculations are performed to investigate the structural stability, electronic structure and mechanical properties of rubidium metal hydrides RbMH4（M = B, Al, Ga） for five different crystal structures, namely hexagonal（P63mc）, tetragonal（P42/nmc）, tetragonal（P421c）, orthorhombic（Pnma） and monoclinic（P21/c）. Among the considered structures, tetragonal（P421c） phase is found to be the most stable one for these metal hydrides at normal pressure. A pressure-induced structural phase transition from tetragonal（P421c） to monoclinic（P21/c） phase is observed in all the three metal hydrides. The electronic structure reveals that these hydrides are wide band gap semiconductors. The calculated elastic constants indicate that these alkali metal tetrahydrides are mechanically stable at normal pressure.展开更多
Structural, electronic and mechanical properties of the nH-SiC （n = 2, 4, 6, 8 and 10） polytypes are calculated by using the first-principles calculations based on the density-functional theory approach. The optimiz...Structural, electronic and mechanical properties of the nH-SiC （n = 2, 4, 6, 8 and 10） polytypes are calculated by using the first-principles calculations based on the density-functional theory approach. The optimized lattice parameters of nH-SiC are in good agreement with the experimental data. The mechanical properties, including elastic constants, bulk modulus, Young＇s modulus, shear modulus and Poisson＇s ratio, are calculated. The analysis of elastic properties indicates that the effects of n on the mechanical properties of the five nil-SiC structures have no difference. The indirect band gap relationship for the live polytypes is Ebg2H 〉 Ebg4H 〉 Ebg6H 〉 Ebg10H 〉 EbgsH.展开更多
The Measures for the Administration of the Import of Mechanical and Electronic' Products co-formulated by the Ministry of Commerce,the General Administration of Customs and the General Administration of Quality Su...The Measures for the Administration of the Import of Mechanical and Electronic' Products co-formulated by the Ministry of Commerce,the General Administration of Customs and the General Administration of Quality Supervision,Inspection and Quarantine,was hereby promul- gated,which entered into force as of May 1,2008.展开更多
With the arrival of the intelligence era of Industry 4.0,social development has shown complex and diversified characteristics,gradually forming an innovation ecological environment constructed by vertical interaction ...With the arrival of the intelligence era of Industry 4.0,social development has shown complex and diversified characteristics,gradually forming an innovation ecological environment constructed by vertical interaction of multi-layer innovation systems and horizontal collaboration of multiple organizations and departments,which has posed extremely challenging requirements for higher engineering education to cultivate engineering talents with comprehensive engineering qualities who can solve complex engineering problems.However,practical engineering problems may involve a complex knowledge chain of interdisciplinary and multi-disciplinary cross-coupling.Therefore,higher engineering education needs to form a new interdisciplinary and multi-disciplinary integrated engineering innovation talent training system.Based on the characteristics of the mechanical and electronic engineering major,we will reshape and reconstruct the core courses of the mechanical and electronic engineering major.Two core courses are formed:Drive and Measurement and Control I and Drive and Measurement and Control II,with information flow and energy flow as the main lines,following up with the comprehensive practical curriculum system based on the unity of knowledge and practice and ability-oriented thinking,supporting teaching objectives,promoting students’individual development,and providing guidelines for relevant curriculum reforms.展开更多
Under the background of new engineering,the reform of the comprehensive practical course system for mechanical and electronic engineering majors actively responds to the challenges posed by the new round of technologi...Under the background of new engineering,the reform of the comprehensive practical course system for mechanical and electronic engineering majors actively responds to the challenges posed by the new round of technological revolution and industrial transformation to higher education,cultivating top-notch innovative intellectuals with comprehensive engineering qualities,meeting the requirements of being able to solve complex engineering problems rather than just cognitive capabilities,forming two core courses through reconstructing and reshaping the core courses of the major.The core courses include Drive,Measurement,and Control I and Drive,Measurement,and Control II,which highlight the comprehensive framework of mechanical and electronic engineering professional knowledge,continuing the comprehensive practical course system based on the unity of knowledge and practice,following the trend of new engineering,highlighting the practicality of professional innovation,assisting engineering education reform,and promoting high-quality development of new engineering professionals cultivation.展开更多
Mechanical and electronic engineering covers many subjects, and automatic mechanical manufacturing is the key. Compared with traditional mechanical manufacturing, it can be seen that the mechanical equipment controlle...Mechanical and electronic engineering covers many subjects, and automatic mechanical manufacturing is the key. Compared with traditional mechanical manufacturing, it can be seen that the mechanical equipment controlled by automatic technology can effectively improve the production efficiency. In our country, artificial intelligence technology is highly valued, and its development speed is also fast, especially the advantage of data processing is great. Its full application can promote the mechanical and electronic engineering, and the economic benefits of related enterprises will also be improved. Based on this, this paper mainly discusses how to apply artificial intelligence technology in mechanical and electronic engineering.展开更多
Electrochemical nitrate reduction(NO_(3)RR)offers a promising avenue for treating nitrate-contaminated water and recovering ammonia(NH_(3)),yet the complexities of direct electron transfer(DET)and hydrogen atom transf...Electrochemical nitrate reduction(NO_(3)RR)offers a promising avenue for treating nitrate-contaminated water and recovering ammonia(NH_(3)),yet the complexities of direct electron transfer(DET)and hydrogen atom transfer(HAT)mechanisms crucial for efficiency remain elusive.This study bridges the gap with a combined experimental and theoretical approach,elucidating the impact of catalyst structure on NO3RR pathways.We discover that catalysts favoring strong NO_(3^(-))adsorption and efficient water dissociation were more inclined towards DET,enhancing denitrification.The Fe@Fe_(3)O_(4)/FF cathode,leveraging the synergistic interplay between metallic Fe and Fe_(3)O_(4),excelled in NO3RR via DET,achieving an NH3yield of 0.28 mmol h-1cm-2and a Faradaic efficiency of 95.7%for NH3at-1.6 V(vs.SCE),with minimal nitrite accumulation at 100 mmol/L nitrate.Conversely,the Fe/FF and Fe_(3)O_(4)/CC cathodes showed reduced NH3production and increased nitrite levels,attributed to the lack of Fe_(3)O_(4)and metallic Fe,respectively,resulting in a dominant HAT mechanism.Moreover,Fe@Fe_(3)O_(4)/FF facilitated complete denitrification in real wastewater treatment by harnessing Cl^(-)for electrochemically mediated breakpoint chlorination.This research not only deepens our understanding of NO3RR mechanisms but also paves the way for designing superior nitrate reduction catalysts.展开更多
The advanced oxidation system based on peracetic acid(PAA)has been proved to be a green and safe oxidation decontamination technology.Among them,the key challenge and complexity in current research lies in the directi...The advanced oxidation system based on peracetic acid(PAA)has been proved to be a green and safe oxidation decontamination technology.Among them,the key challenge and complexity in current research lies in the directional induction of PAA and its utilization for selective removal of refractory pollutants.This study prepared nitrogen-doped biochar(NBC)using compound pharmaceutical residues commonly found in traditional Chinese medicine as a precursor.A system based on NBC-activated PAA was constructed for sulfamethoxazole(SMX)degradation.The introduction of nitrogen significantly enhanced the degree of graphitization in NBC.The degradation system achieved 87.89%SMX degradation efficiency within 60 min.Furthermore,the formation of the intricate NBC-PAA*complex detected by in-situ Raman was of paramount importance as it facilitates enhanced electron transfer processes within the complex,thereby promoting PAA decomposition through electron loss.The formation of a new complex between SMX and NBC-PAA*facilitated the completion of electron transfer process within the complex.In summary,this study explored a novel approach for treating and disposing of solid waste from Chinese medicine residue by successfully inducing non-free radical degradation pathway using PAA system.It offers fresh insights and ideas in the fields of water treatment and solid waste management.展开更多
Addressing the growing challenge of water contamination,this study comparatively evaluated a persulfate(PDS)system activated by nonradical nitrogen-doped carbon nanotubes(N-CNTs)versus a PDS system activated by radica...Addressing the growing challenge of water contamination,this study comparatively evaluated a persulfate(PDS)system activated by nonradical nitrogen-doped carbon nanotubes(N-CNTs)versus a PDS system activated by radical-based iron(Fe^(2+)),both used for the degradation of bisphenol A(BPA).The N-CNTs/PDS system,driven by the electron transfer mechanism,achieved remarkable 90.9%BPA removal within 30 min at high BPA concentrations,significantly outperforming the Fe^(2+)/PDS system,which attained only 38.9%removal.The N-CNTs/PDS system maintained robust degradation efficiency across a wide range of BPA concentrations and exhibited a high degree of resilience in diverse water matrices.By directly abstracting electrons from BPA molecules,the N-CNTs/PDS system effectively minimised oxidant wastage and mitigated the risk of secondary pollution,ensuring efficient utilisation of active sites on N-CNTs and sustaining a high catalytic rate.The formation of the N-CNTs-PDS^(*)complex significantly enhanced BPA degradation and mineralisation,thereby optimising PDS consumption.These findings highlight the unparalleled advantages of the N-CNTs/PDS system in managing complex wastewater,offering a promising and innovative solution for treating complex industrial wastewater and advancing environmental remediation efforts.展开更多
Photocatalytic and photoelectrocatalytic H_(2)O_(2)production has been identified as a significant pathway within environmental pollution control,green energy,medical treatment,sterilization and disinfection.However,c...Photocatalytic and photoelectrocatalytic H_(2)O_(2)production has been identified as a significant pathway within environmental pollution control,green energy,medical treatment,sterilization and disinfection.However,conventional single-material photocatalysts struggle to fulfill the stringent criteria of high efficiency,stability,cost-effectiveness,and responsiveness to visible light.The elevated recombination rates of photogenerated charge carriers,coupled with the suboptimal utilization of visible light,have collectively constrained the photocatalytic and photoelectrocatalytic H_(2)O_(2)production.Heterojunction catalysts for the production of H_(2)O_(2)has become a focal point of research.This review commences by elucidating the fundaments underlying the photocatalytic and photoelectrocatalytic H_(2)O_(2)production.Subsequently,it delineates the distinctive electron transfer mechanisms of Z-scheme and S-scheme heterojunctions,which exhibit enhanced efficiency in the photocatalytic and photoelectrocatalytic H_(2)O_(2)production,along with a summary of strategies for the improvement of photocatalyst and photoelectrocatalyst performance.Furthermore,this review also outlines the latest fabrication strategies,state-of-the-art in-situ characterization techniques,machine learning and density functional theory(DFT)simulations for Z-scheme or Sscheme catalysts for the photocatalytic and photoelectrocatalytic H_(2)O_(2)production,and briefly describes the multifunctional applications in H_(2)O_(2)production.Ultimately,the review contemplates the prospective developmental trajectories and application potential of these heterojunction configurations for the photocatalytic and photoelectrocatalytic H_(2)O_(2)production.展开更多
Halogenated aromatic compounds have attracted increasing concerns due to their toxicity and persistency in the environment, and dehalogenation is one of the promising treatment and detoxification methods. Herein, we s...Halogenated aromatic compounds have attracted increasing concerns due to their toxicity and persistency in the environment, and dehalogenation is one of the promising treatment and detoxification methods. Herein, we systematically studied the debromination efficiency and mechanism of para-bromophenol（4-BP） by a recently developed UV/sulfite process. 4-BP underwent rapid degradation with the kinetics accelerated with the increasing sulfite concentration, pH（6.1–10） and temperature, whereas inhibited by dissolved oxygen and organic solvents. The apparent activation energy was estimated to be 27.8 kJ/mol. The degradation mechanism and pathways of 4-BP were explored by employing N2O and nitrate as the electron scavengers and liquid chromatography/mass spectrometry to identify the intermediates. 4-BP degradation proceeded via at least two pathways including direct photolysis and hydrated electron-induced debromination. The contributions of both pathways were distinguished by quantifying the quantum yields of 4-BP via direct photolysis and hydrated electron production in the system. 4-BP could be readily completely debrominated with all the substituted Br released as Br-, and the degradation pathways were also proposed. This study would shed new light on the efficient dehalogenation of brominated aromatics by using the UV/sulfite process.展开更多
Nanoporous Gd2O3 powders(NGPs) with different specific surface areas were prepared by a nonaqueous sol-gel method and utilized to tune the exothermal decomposition of ammonium perchlorate(AP) for enhanced propellant e...Nanoporous Gd2O3 powders(NGPs) with different specific surface areas were prepared by a nonaqueous sol-gel method and utilized to tune the exothermal decomposition of ammonium perchlorate(AP) for enhanced propellant efficiency and improved safety.It is found that with the increasing dosage of NGPs into AP,the two exothermal peaks of AP merge into one intense exothermal peak,indicating that an "energy stacking" has been achieved.Meanwhile,the unique delay of the first exothermal peak of AP is conducive to the safety of AP in application process.Furthermore,the dependence of decomposition heat of AP on dosage and calcination temperature is more evident than on the surface areas of NGPs,suggesting that the promotion effect of NGPs on the thermal decomposition of AP does not only rely on the surface interaction.Therefore,an electron transfer mechanism is proposed to illustrate the decomposition process of AP tuned by NGPs.展开更多
Electron beam melting （EBM） has been used to manufacture β-type Ti-24Nb-4Zr-8Sn porous compo- nents with 70% porosity, EBM-produced components have favorable structural features （i.e. smooth strut surfaces, fewer ...Electron beam melting （EBM） has been used to manufacture β-type Ti-24Nb-4Zr-8Sn porous compo- nents with 70% porosity, EBM-produced components have favorable structural features （i.e. smooth strut surfaces, fewer defects） and an （α ＋ β）-type microstructure, similar to that subjected to aging treat- ment. EBM-produced components exhibit more than twice the strength-to-modulus ratio of porous Ti- 6A1-4V components having the same porosity. The processing-microstructure-property relationship and deformation behavior of EBM-produced components are discussed in detail. Such porous titanium com- ponents composed of non-toxic elements and having high strength-to-modulus ratio are highly attractive for biomedical applications.展开更多
The cyclic extrusion compression （CEC） was applied to severely deform the as-extruded GW102K （Mg- 10.0Gd-2.0Y-0.5Zr, wt%） alloy at 350, 400, and 450 ℃, respectively. The microstructure, texture, and grain boundar...The cyclic extrusion compression （CEC） was applied to severely deform the as-extruded GW102K （Mg- 10.0Gd-2.0Y-0.5Zr, wt%） alloy at 350, 400, and 450 ℃, respectively. The microstructure, texture, and grain boundary character distribution of the CECed alloy were investigated in the present work. The mechan- ical properties were measured by uniaxial tension at room temperature. The crack initiation on the longitudinal section near the tensile fracture-surface was investigated by high-resolution scanning elec- tron microscopy （SEM）. The result shows that the microstructure was dramatically refined by dynamic recrystallization （DRX）. The initial fiber texture was disintegrated and obviously weakened. The 8-passes/ 350 ℃ CECed alloy exhibited yield strength of 318 MPa with an elongation-to-fracture of 16.8%, increased by 41.3% and 162.5%, respectively. Moreover, the elongation-to-fracture of the 8-passes/450 ℃ CECed alloy significantly increased more than 3 times than that of the received alloy. The cracks were mainly initi- ated at twin boundaries and second phase/matrix interfaces during tensile deformation. The microstructure refinement was considered to result in the dramatically enhanced of the strength and ductility. In ad- dition, the texture randomization during CEC is beneficial for enhancing ductility. The standard positive Hall-Petch relationships have been obtained for the CECed GW102K alloy.展开更多
Recalcitrance and the inherent heterogeneity of lignin structure are the major bottlenecks to impede the popularization of lignin-based chemicals production processes.Recent works suggested a promising pathway for lig...Recalcitrance and the inherent heterogeneity of lignin structure are the major bottlenecks to impede the popularization of lignin-based chemicals production processes.Recent works suggested a promising pathway for lignin depolymerization and lignin-derived bio-oil upgrading via an electrochemical biorefinery(a process in which lignin valorization is performed via electrochemical oxidation or reduction).This review presents the progress on chemicals synthesis and bio-oil upgrading from lignin by an electrochemical biorefinery,relating to the lignin biosynthesis pathway,reaction pathway of lignin electrochemical conversion,inner-sphere and outer-sphere electron transfer mechanism,basic kinetics and thermodynamics in electrochemistry,and the recent embodiments analysis with the emphasis on the respective feature and limitation for lignin electrochemical oxidative and reductive conversion.Lastly,the challenge and perspective associated with lignin electrochemical biorefinery are discussed.Present-day results indicate that more work should be performed to promote efficiency,selectivity,and stability in pursuing a lignin electrochemical biorefinery.One of the most promising developing directions appears to be integrating various types of lignin electrochemical conversion strategies and other existing or evolving lignin valorization technologies.This review aims to provide more references and discussion on the development for lignin electrochemical biorefinery.展开更多
The mechanism of grain fracturing in a zirconia metering nozzle used in the continuous casting process was studied. The phase composition, microstructure, and chemical composition of the residual samples were studied ...The mechanism of grain fracturing in a zirconia metering nozzle used in the continuous casting process was studied. The phase composition, microstructure, and chemical composition of the residual samples were studied using an X-ray fluorescence analyzer, scanning electron microscope, and electron probe. Results revealed that the composition, structure, and mineral phase of the original layer, transition layer, and affected layer of the metering nozzle differed because of stabilizer precipitation and steel slag permeation. The stabilizer MgO formed low-melting phases with steel slag and impure SiO2 on the boundaries（pores） of zirconia grains; consequently, grain fracturing occurred and accelerated damage to the metering nozzle was observed.展开更多
Electrocatalytic reduction of nitrogen into ammonia(NH_(3))is a highly attractive but challenging route for NH_(3)production.We propose to realize a synergetic work of multi reaction sites to overcome the limitation o...Electrocatalytic reduction of nitrogen into ammonia(NH_(3))is a highly attractive but challenging route for NH_(3)production.We propose to realize a synergetic work of multi reaction sites to overcome the limitation of sustainable NH_(3)production.Herein,using ruthenium-sulfur-carbon(Ru-S-C)catalyst as a prototype,we show that the Ru/S dual-site cooperates to catalyse eletrocatalytic nitrogen reduction reaction(eNRR)at ambient conditions.With the combination of theoretical calculations,in situ Raman spectroscopy,and experimental observation,we demonstrate that such Ru/S dual-site cooperation greatly facilitates the activation and first protonation of N_(2)in the rate-determining step of eNRR.As a result,Ru-S-C catalyst exhibits significantly enhanced eNRR performance compared with the routine Ru-N-C catalyst via a single-site catalytic mechanism.We anticipate that our specifically designed dual-site collaborative catalytic mechanism will open up a new way to offers new opportunities for advancing sustainable NH_(3)production.展开更多
Mg-9Al-6Sn-3Zn （wt%） alloy was extruded and heat treated in T5 and T6 conditions, and its mechanical properties and microstructures were investigated. The extruded product can be slightly strengthened by the T5 trea...Mg-9Al-6Sn-3Zn （wt%） alloy was extruded and heat treated in T5 and T6 conditions, and its mechanical properties and microstructures were investigated. The extruded product can be slightly strengthened by the T5 treatment as a result of sparse and heterogeneous precipitation. Significant increase in strength is achieved by the T6 treatment, and this is mostly attributed to the formation of lamellar discontinuous Mg17Al12 precipitates. The segregation of Al and Zn at grain boundaries is responsible for the discontinuous Mg17Al12 nucleation. The T6-treated alloy exhibits a tensile yield strength of 341 MPa and an ultimate tensile strength of 409 MPa, together with an elongation to fracture of 4%.展开更多
文摘Conventional electronics is planar, hard, and rigid due to the intrinsic brittle nature of inorganic semiconductor materials （e.g., silicon and gallium arsenide）. The modern electronic technology has typically been concerned with large or small but durable and long-lasting electronics. Recently developed materials and mechanics concepts yield unconventional electronics with unique characteristics （e.g., deformable, degradable, etc.）.
基金financially supported by the Natural Science Foundation of Hebei Province,China(No.E2013502272)
文摘Ceramic materials were investigated as thermal barrier coatings and electrolytes. Electrophoretic deposition（EPD） and physical vapor deposition（PVD） were employed to fabricate samples, and the mechanical properties and microstructure were examined by nanoindentation and microscopy, respectively. Yttria-stabilized zirconia/alumina（YSZ/Al2O3） composite coatings, a candidate for thermal barrier coatings, yield a kinky, rather than smooth, load–displacement curve. Scanning electron microscope（SEM） examination reveals that the kinky curve is because of the porous microstructure and cracks are caused by the compression of the indenter. Li0.34La0.51 Ti O2.94（LLTO） on Si/Sr Ru O3（Si/SRO） substrates, an ionic conductor in nature, demonstrates electronic performance. Although SEM images show a continuous and smooth microstructure, a close examination of the microstructure by transmission electron microscopy（TEM） reveals that the observed spikes indicate electronic performance. Therefore, we can conclude that ceramic coatings could serve multiple purposes but their properties are microstructure-dependent.
文摘Ab initio calculations are performed to investigate the structural stability, electronic structure and mechanical properties of rubidium metal hydrides RbMH4（M = B, Al, Ga） for five different crystal structures, namely hexagonal（P63mc）, tetragonal（P42/nmc）, tetragonal（P421c）, orthorhombic（Pnma） and monoclinic（P21/c）. Among the considered structures, tetragonal（P421c） phase is found to be the most stable one for these metal hydrides at normal pressure. A pressure-induced structural phase transition from tetragonal（P421c） to monoclinic（P21/c） phase is observed in all the three metal hydrides. The electronic structure reveals that these hydrides are wide band gap semiconductors. The calculated elastic constants indicate that these alkali metal tetrahydrides are mechanically stable at normal pressure.
基金Supported by the National Natural Science Foundation of China under Grant No 51372203the National Basic Research Program of China under Grant No 2011CB605806+1 种基金the Basic Research Foundation of Northwestern Polytechnical University under Grant Nos JCY20130114 and JCY20110248the Foreign Talents Introduction and Academic Exchange Program under Grant No B08040
文摘Structural, electronic and mechanical properties of the nH-SiC （n = 2, 4, 6, 8 and 10） polytypes are calculated by using the first-principles calculations based on the density-functional theory approach. The optimized lattice parameters of nH-SiC are in good agreement with the experimental data. The mechanical properties, including elastic constants, bulk modulus, Young＇s modulus, shear modulus and Poisson＇s ratio, are calculated. The analysis of elastic properties indicates that the effects of n on the mechanical properties of the five nil-SiC structures have no difference. The indirect band gap relationship for the live polytypes is Ebg2H 〉 Ebg4H 〉 Ebg6H 〉 Ebg10H 〉 EbgsH.
文摘The Measures for the Administration of the Import of Mechanical and Electronic' Products co-formulated by the Ministry of Commerce,the General Administration of Customs and the General Administration of Quality Supervision,Inspection and Quarantine,was hereby promul- gated,which entered into force as of May 1,2008.
文摘With the arrival of the intelligence era of Industry 4.0,social development has shown complex and diversified characteristics,gradually forming an innovation ecological environment constructed by vertical interaction of multi-layer innovation systems and horizontal collaboration of multiple organizations and departments,which has posed extremely challenging requirements for higher engineering education to cultivate engineering talents with comprehensive engineering qualities who can solve complex engineering problems.However,practical engineering problems may involve a complex knowledge chain of interdisciplinary and multi-disciplinary cross-coupling.Therefore,higher engineering education needs to form a new interdisciplinary and multi-disciplinary integrated engineering innovation talent training system.Based on the characteristics of the mechanical and electronic engineering major,we will reshape and reconstruct the core courses of the mechanical and electronic engineering major.Two core courses are formed:Drive and Measurement and Control I and Drive and Measurement and Control II,with information flow and energy flow as the main lines,following up with the comprehensive practical curriculum system based on the unity of knowledge and practice and ability-oriented thinking,supporting teaching objectives,promoting students’individual development,and providing guidelines for relevant curriculum reforms.
文摘Under the background of new engineering,the reform of the comprehensive practical course system for mechanical and electronic engineering majors actively responds to the challenges posed by the new round of technological revolution and industrial transformation to higher education,cultivating top-notch innovative intellectuals with comprehensive engineering qualities,meeting the requirements of being able to solve complex engineering problems rather than just cognitive capabilities,forming two core courses through reconstructing and reshaping the core courses of the major.The core courses include Drive,Measurement,and Control I and Drive,Measurement,and Control II,which highlight the comprehensive framework of mechanical and electronic engineering professional knowledge,continuing the comprehensive practical course system based on the unity of knowledge and practice,following the trend of new engineering,highlighting the practicality of professional innovation,assisting engineering education reform,and promoting high-quality development of new engineering professionals cultivation.
文摘Mechanical and electronic engineering covers many subjects, and automatic mechanical manufacturing is the key. Compared with traditional mechanical manufacturing, it can be seen that the mechanical equipment controlled by automatic technology can effectively improve the production efficiency. In our country, artificial intelligence technology is highly valued, and its development speed is also fast, especially the advantage of data processing is great. Its full application can promote the mechanical and electronic engineering, and the economic benefits of related enterprises will also be improved. Based on this, this paper mainly discusses how to apply artificial intelligence technology in mechanical and electronic engineering.
基金support from the National Natural Science Foundation of China(Nos.U21A2034 and 21876052)the Guangdong Special Support Plan for Innovation Teams(No.2019BT02L218)+1 种基金the Guangdong Special Support Plan for Young Top-notch Talents(No.2019TQ05L179)the Natural Science Foundation of Guangdong Province,China(No.2021B1515120077)。
文摘Electrochemical nitrate reduction(NO_(3)RR)offers a promising avenue for treating nitrate-contaminated water and recovering ammonia(NH_(3)),yet the complexities of direct electron transfer(DET)and hydrogen atom transfer(HAT)mechanisms crucial for efficiency remain elusive.This study bridges the gap with a combined experimental and theoretical approach,elucidating the impact of catalyst structure on NO3RR pathways.We discover that catalysts favoring strong NO_(3^(-))adsorption and efficient water dissociation were more inclined towards DET,enhancing denitrification.The Fe@Fe_(3)O_(4)/FF cathode,leveraging the synergistic interplay between metallic Fe and Fe_(3)O_(4),excelled in NO3RR via DET,achieving an NH3yield of 0.28 mmol h-1cm-2and a Faradaic efficiency of 95.7%for NH3at-1.6 V(vs.SCE),with minimal nitrite accumulation at 100 mmol/L nitrate.Conversely,the Fe/FF and Fe_(3)O_(4)/CC cathodes showed reduced NH3production and increased nitrite levels,attributed to the lack of Fe_(3)O_(4)and metallic Fe,respectively,resulting in a dominant HAT mechanism.Moreover,Fe@Fe_(3)O_(4)/FF facilitated complete denitrification in real wastewater treatment by harnessing Cl^(-)for electrochemically mediated breakpoint chlorination.This research not only deepens our understanding of NO3RR mechanisms but also paves the way for designing superior nitrate reduction catalysts.
基金supported by the National Natural Science Foundation of China(No.52200049)the China Postdoctoral Science Foundation(No.2022TQ0089)+2 种基金the Heilongjiang Province Postdoctoral Science Foundation(No.LBH-Z22181)the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(No.2024TS28)the Fundamental Research Funds for the Central Universities。
文摘The advanced oxidation system based on peracetic acid(PAA)has been proved to be a green and safe oxidation decontamination technology.Among them,the key challenge and complexity in current research lies in the directional induction of PAA and its utilization for selective removal of refractory pollutants.This study prepared nitrogen-doped biochar(NBC)using compound pharmaceutical residues commonly found in traditional Chinese medicine as a precursor.A system based on NBC-activated PAA was constructed for sulfamethoxazole(SMX)degradation.The introduction of nitrogen significantly enhanced the degree of graphitization in NBC.The degradation system achieved 87.89%SMX degradation efficiency within 60 min.Furthermore,the formation of the intricate NBC-PAA*complex detected by in-situ Raman was of paramount importance as it facilitates enhanced electron transfer processes within the complex,thereby promoting PAA decomposition through electron loss.The formation of a new complex between SMX and NBC-PAA*facilitated the completion of electron transfer process within the complex.In summary,this study explored a novel approach for treating and disposing of solid waste from Chinese medicine residue by successfully inducing non-free radical degradation pathway using PAA system.It offers fresh insights and ideas in the fields of water treatment and solid waste management.
基金supported by the Natural Science Foundation of Inner Mongolia Autonomous Region of China(Grant No.2024LHMS05048).
文摘Addressing the growing challenge of water contamination,this study comparatively evaluated a persulfate(PDS)system activated by nonradical nitrogen-doped carbon nanotubes(N-CNTs)versus a PDS system activated by radical-based iron(Fe^(2+)),both used for the degradation of bisphenol A(BPA).The N-CNTs/PDS system,driven by the electron transfer mechanism,achieved remarkable 90.9%BPA removal within 30 min at high BPA concentrations,significantly outperforming the Fe^(2+)/PDS system,which attained only 38.9%removal.The N-CNTs/PDS system maintained robust degradation efficiency across a wide range of BPA concentrations and exhibited a high degree of resilience in diverse water matrices.By directly abstracting electrons from BPA molecules,the N-CNTs/PDS system effectively minimised oxidant wastage and mitigated the risk of secondary pollution,ensuring efficient utilisation of active sites on N-CNTs and sustaining a high catalytic rate.The formation of the N-CNTs-PDS^(*)complex significantly enhanced BPA degradation and mineralisation,thereby optimising PDS consumption.These findings highlight the unparalleled advantages of the N-CNTs/PDS system in managing complex wastewater,offering a promising and innovative solution for treating complex industrial wastewater and advancing environmental remediation efforts.
基金the financial support provided by the National Natural Science Foundation of China(Nos.22262024,52470078,62004143)Jiangxi Province Academic and Technical Leader of Major Disciplines(No.20232BCJ22008)+4 种基金the Key Project of Natural Science Foundation of Jiangxi Province(Nos.20232ACB204007)Double Thousand Talent Plan of Jiangxi Provincethe Natural Science Foundation of Jiangxi Province(No.2022ACB203014)the Key R&D Program of Hubei Province(No.2022BAA084)the Innovation Project of Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education(No.LCX202404)。
文摘Photocatalytic and photoelectrocatalytic H_(2)O_(2)production has been identified as a significant pathway within environmental pollution control,green energy,medical treatment,sterilization and disinfection.However,conventional single-material photocatalysts struggle to fulfill the stringent criteria of high efficiency,stability,cost-effectiveness,and responsiveness to visible light.The elevated recombination rates of photogenerated charge carriers,coupled with the suboptimal utilization of visible light,have collectively constrained the photocatalytic and photoelectrocatalytic H_(2)O_(2)production.Heterojunction catalysts for the production of H_(2)O_(2)has become a focal point of research.This review commences by elucidating the fundaments underlying the photocatalytic and photoelectrocatalytic H_(2)O_(2)production.Subsequently,it delineates the distinctive electron transfer mechanisms of Z-scheme and S-scheme heterojunctions,which exhibit enhanced efficiency in the photocatalytic and photoelectrocatalytic H_(2)O_(2)production,along with a summary of strategies for the improvement of photocatalyst and photoelectrocatalyst performance.Furthermore,this review also outlines the latest fabrication strategies,state-of-the-art in-situ characterization techniques,machine learning and density functional theory(DFT)simulations for Z-scheme or Sscheme catalysts for the photocatalytic and photoelectrocatalytic H_(2)O_(2)production,and briefly describes the multifunctional applications in H_(2)O_(2)production.Ultimately,the review contemplates the prospective developmental trajectories and application potential of these heterojunction configurations for the photocatalytic and photoelectrocatalytic H_(2)O_(2)production.
基金supported by the National Natural Science Foundation of China(No.21307057)the Natural Science Foundation of Jiangsu Province(No.BK20130577)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(SRFDP,No.20130091120014)the Fundamental Research Funds for the Central Universities(No.20620140128)
文摘Halogenated aromatic compounds have attracted increasing concerns due to their toxicity and persistency in the environment, and dehalogenation is one of the promising treatment and detoxification methods. Herein, we systematically studied the debromination efficiency and mechanism of para-bromophenol（4-BP） by a recently developed UV/sulfite process. 4-BP underwent rapid degradation with the kinetics accelerated with the increasing sulfite concentration, pH（6.1–10） and temperature, whereas inhibited by dissolved oxygen and organic solvents. The apparent activation energy was estimated to be 27.8 kJ/mol. The degradation mechanism and pathways of 4-BP were explored by employing N2O and nitrate as the electron scavengers and liquid chromatography/mass spectrometry to identify the intermediates. 4-BP degradation proceeded via at least two pathways including direct photolysis and hydrated electron-induced debromination. The contributions of both pathways were distinguished by quantifying the quantum yields of 4-BP via direct photolysis and hydrated electron production in the system. 4-BP could be readily completely debrominated with all the substituted Br released as Br-, and the degradation pathways were also proposed. This study would shed new light on the efficient dehalogenation of brominated aromatics by using the UV/sulfite process.
基金Project supported by the National Natural Science Foundation of China(51864033,51274123,21761020)the National Key Basic Research Program of China(973 Program,2012CBA01204)Jiangxi Provincial Scientific&Technological Support Project of China(20132BBE500041)
文摘Nanoporous Gd2O3 powders(NGPs) with different specific surface areas were prepared by a nonaqueous sol-gel method and utilized to tune the exothermal decomposition of ammonium perchlorate(AP) for enhanced propellant efficiency and improved safety.It is found that with the increasing dosage of NGPs into AP,the two exothermal peaks of AP merge into one intense exothermal peak,indicating that an "energy stacking" has been achieved.Meanwhile,the unique delay of the first exothermal peak of AP is conducive to the safety of AP in application process.Furthermore,the dependence of decomposition heat of AP on dosage and calcination temperature is more evident than on the surface areas of NGPs,suggesting that the promotion effect of NGPs on the thermal decomposition of AP does not only rely on the surface interaction.Therefore,an electron transfer mechanism is proposed to illustrate the decomposition process of AP tuned by NGPs.
基金supported partially by the National High-Tech R&D Program of China(863 Program,No.2015AA033702)the National Basic Research Program of China(Nos.2012CB619103 and 2012CB933901)+1 种基金the National Natural Science Foundation of China(Nos.51271182 and 51501200)the Australian Research Council Discovery Project(Nos.DP110101653 and DP130103592)
文摘Electron beam melting （EBM） has been used to manufacture β-type Ti-24Nb-4Zr-8Sn porous compo- nents with 70% porosity, EBM-produced components have favorable structural features （i.e. smooth strut surfaces, fewer defects） and an （α ＋ β）-type microstructure, similar to that subjected to aging treat- ment. EBM-produced components exhibit more than twice the strength-to-modulus ratio of porous Ti- 6A1-4V components having the same porosity. The processing-microstructure-property relationship and deformation behavior of EBM-produced components are discussed in detail. Such porous titanium com- ponents composed of non-toxic elements and having high strength-to-modulus ratio are highly attractive for biomedical applications.
基金supported by the National Natural Science Foundation of China (No. 51204117)Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxithe Natural Science Foundation of Shanxi province (No. 2015021017)
文摘The cyclic extrusion compression （CEC） was applied to severely deform the as-extruded GW102K （Mg- 10.0Gd-2.0Y-0.5Zr, wt%） alloy at 350, 400, and 450 ℃, respectively. The microstructure, texture, and grain boundary character distribution of the CECed alloy were investigated in the present work. The mechan- ical properties were measured by uniaxial tension at room temperature. The crack initiation on the longitudinal section near the tensile fracture-surface was investigated by high-resolution scanning elec- tron microscopy （SEM）. The result shows that the microstructure was dramatically refined by dynamic recrystallization （DRX）. The initial fiber texture was disintegrated and obviously weakened. The 8-passes/ 350 ℃ CECed alloy exhibited yield strength of 318 MPa with an elongation-to-fracture of 16.8%, increased by 41.3% and 162.5%, respectively. Moreover, the elongation-to-fracture of the 8-passes/450 ℃ CECed alloy significantly increased more than 3 times than that of the received alloy. The cracks were mainly initi- ated at twin boundaries and second phase/matrix interfaces during tensile deformation. The microstructure refinement was considered to result in the dramatically enhanced of the strength and ductility. In ad- dition, the texture randomization during CEC is beneficial for enhancing ductility. The standard positive Hall-Petch relationships have been obtained for the CECed GW102K alloy.
基金supported by the National Natural Science Foundation of China(21876030)the International Cooperation Project of Science and Technology Commission of Shanghai Municipality(18230710700)。
文摘Recalcitrance and the inherent heterogeneity of lignin structure are the major bottlenecks to impede the popularization of lignin-based chemicals production processes.Recent works suggested a promising pathway for lignin depolymerization and lignin-derived bio-oil upgrading via an electrochemical biorefinery(a process in which lignin valorization is performed via electrochemical oxidation or reduction).This review presents the progress on chemicals synthesis and bio-oil upgrading from lignin by an electrochemical biorefinery,relating to the lignin biosynthesis pathway,reaction pathway of lignin electrochemical conversion,inner-sphere and outer-sphere electron transfer mechanism,basic kinetics and thermodynamics in electrochemistry,and the recent embodiments analysis with the emphasis on the respective feature and limitation for lignin electrochemical oxidative and reductive conversion.Lastly,the challenge and perspective associated with lignin electrochemical biorefinery are discussed.Present-day results indicate that more work should be performed to promote efficiency,selectivity,and stability in pursuing a lignin electrochemical biorefinery.One of the most promising developing directions appears to be integrating various types of lignin electrochemical conversion strategies and other existing or evolving lignin valorization technologies.This review aims to provide more references and discussion on the development for lignin electrochemical biorefinery.
基金funded by the National Natural Science Foundation of China(51372193)the Natural Science Basic Research Plan in the Shaanxi Province of China(2014JM6224)
文摘The mechanism of grain fracturing in a zirconia metering nozzle used in the continuous casting process was studied. The phase composition, microstructure, and chemical composition of the residual samples were studied using an X-ray fluorescence analyzer, scanning electron microscope, and electron probe. Results revealed that the composition, structure, and mineral phase of the original layer, transition layer, and affected layer of the metering nozzle differed because of stabilizer precipitation and steel slag permeation. The stabilizer MgO formed low-melting phases with steel slag and impure SiO2 on the boundaries（pores） of zirconia grains; consequently, grain fracturing occurred and accelerated damage to the metering nozzle was observed.
文摘Electrocatalytic reduction of nitrogen into ammonia(NH_(3))is a highly attractive but challenging route for NH_(3)production.We propose to realize a synergetic work of multi reaction sites to overcome the limitation of sustainable NH_(3)production.Herein,using ruthenium-sulfur-carbon(Ru-S-C)catalyst as a prototype,we show that the Ru/S dual-site cooperates to catalyse eletrocatalytic nitrogen reduction reaction(eNRR)at ambient conditions.With the combination of theoretical calculations,in situ Raman spectroscopy,and experimental observation,we demonstrate that such Ru/S dual-site cooperation greatly facilitates the activation and first protonation of N_(2)in the rate-determining step of eNRR.As a result,Ru-S-C catalyst exhibits significantly enhanced eNRR performance compared with the routine Ru-N-C catalyst via a single-site catalytic mechanism.We anticipate that our specifically designed dual-site collaborative catalytic mechanism will open up a new way to offers new opportunities for advancing sustainable NH_(3)production.
文摘Mg-9Al-6Sn-3Zn （wt%） alloy was extruded and heat treated in T5 and T6 conditions, and its mechanical properties and microstructures were investigated. The extruded product can be slightly strengthened by the T5 treatment as a result of sparse and heterogeneous precipitation. Significant increase in strength is achieved by the T6 treatment, and this is mostly attributed to the formation of lamellar discontinuous Mg17Al12 precipitates. The segregation of Al and Zn at grain boundaries is responsible for the discontinuous Mg17Al12 nucleation. The T6-treated alloy exhibits a tensile yield strength of 341 MPa and an ultimate tensile strength of 409 MPa, together with an elongation to fracture of 4%.
