Occupational structural transformation is a common pattern during the steady growth of GDP per capita in major economies worldwide.In recent years,there has been a decline in the employment share of goods occupation a...Occupational structural transformation is a common pattern during the steady growth of GDP per capita in major economies worldwide.In recent years,there has been a decline in the employment share of goods occupation and an increase in service occupation within the Chinese manufacturing industry,presenting a trend of occupational structural transformation and rapid development of service-oriented manufacturing.It is an important driving force and typical performance of the high-end,intelligent,and green development of the manufacturing industry.As a strategic general technology which leads the new round of technological revolution and industrial transformation,artificial intelligence(AI)has become a new fundamental force to accelerate the occupational structural transformation and service-oriented manufacturing development in China.Thus,this paper establishes a dynamic general equilibrium model with AI technology and occupational heterogeneity,showing the endogenous mechanism of occupational structural transformation.We find that when AI technology is biased towards goods occupation,and the elasticity of substitution between goods occupation and service occupation is less than 1,then AI will drive the transformation of occupational structure from goods to service within the manufacturing sector,increase the proportion of service-oriented manufacturing,improve labor productivity of manufacturing relative to service and stabilize the real output share of manufacturing.Promoting deeper integration of different occupations,intensifying R&D in AI technology and reducing labor mobility barriers between occupations can effectively accelerate the occupational structural transformation and industrial structural upgrading.We use theoretical analysis and numerical simulation method to show the theoretical mechanism by which AI affects occupational structural transformation and industrial structural transformation from a macroeconomic perspective,and put forward policy implications on how to promote the service-oriented manufacturing development and accelerate the construction of modern industrial system through AI innovation.展开更多
The widespread popularization and application of laser technology have provided a powerful tool for a deeper understanding of the material world and given birth to several emerging research fields.This study mainly fo...The widespread popularization and application of laser technology have provided a powerful tool for a deeper understanding of the material world and given birth to several emerging research fields.This study mainly focuses on the following three key aspects.First,the classical ensemble method is adopted to conduct a comprehensive and in-depth analysis of two-dimensional(2D)matter–wave pulses in Bose–Fermi mixed gases(including linear and nonlinear pulses).Second,under the strict constraints of unitary systems,a coupled Kd V equation is successfully derived,and the prolongation structure theory is skillfully used to carry out detailed calculations and analyses on this equation.Thus,the prolongation algebra of this equation is accurately determined,and the corresponding Lax pair is rigorously derived.Finally,based on the carefully obtained Lax pair from the prolongation structure theory,the soliton solutions of this equation are further analyzed in depth,and intuitive images of each soliton solution are carefully drawn.This lays a solid foundation for subsequent detailed research on these soliton characteristics and provides great convenience.展开更多
Purpose–This paper aims to provide a comprehensive analysis of the strategic adjustments in China’s transportation structure,with a particular focus on the pivotal role of railway freight and its integration into th...Purpose–This paper aims to provide a comprehensive analysis of the strategic adjustments in China’s transportation structure,with a particular focus on the pivotal role of railway freight and its integration into the modern logistics system.It seeks to address the need for a more nuanced understanding of the“road to rail”policy,emphasizing the importance of intermodal collaboration and service of fragmented market demands.Design/methodology/approach–The study employs a transport economics perspective to evaluate the achievements and shortcomings of China’s transportation structure optimization.It bases its assessment of the current state of railway freight logistics,multi-modal transportation and the broader implications for the transportation service market on data analysis.The methodology includes a review of existing policies,an examination of industry practices and a comparative analysis with global trends in railway logistics.Findings–The research underscores the importance of focusing on the development of non-bulk materials,noting the insufficiency in the development of China’s rail multi-modal transportation and highlighting the instructive value of successful cases in open-top container road-rail intermodal transportation.The study posits that the railway sector must enhance cooperation with other market entities,aligning with the lead enterprises in the logistics chain that are characterized by speed,high value and strong coordination capabilities,in order to better serve the transportation market.This approach moves away from a reliance on the railway’s own capabilities alone.Originality/value–This paper offers original insights into the transformation of railway freight in China,contributing to the body of knowledge on transportation economics and logistics.It provides valuable recommendations for policymakers and industry practitioners,emphasizing the strategic importance of railway logistics in the context of China’s economic development and intense competition in the supply chain.The value of the article lies in its comprehensive understanding of the complexities involved in the adjustment of transportation structures,providing direction for the market-oriented reform of China’s railway freight sector.展开更多
Under the guidance of national policies,the“coal to gas”project has become one of the important measures to promote the transformation of energy structure in China.Foshan,an important industrial town in Guangdong pr...Under the guidance of national policies,the“coal to gas”project has become one of the important measures to promote the transformation of energy structure in China.Foshan,an important industrial town in Guangdong province,the implementation of the“coal to gas”policy has demonstrated significance for the optimization of the national energy structure.Through the analysis of the change in Foshan’s energy consumption structure and the implementation of the policy,this paper found that there were some challenges in the policy implementation process,such as high economic cost,lagging infrastructure,low social acceptance,and lack of technical personnel.To address this,suggestions are put forward,including increasing financial subsidies,improving laws and regulations,promoting technological innovation,and encouraging social inclusion policies.These recommendations aim to provide guidance and reference for the remaining“coal to gas”projects and the development of clean energy.展开更多
Significant two-way shape memory effect(TWSME)was achieved in single crystals of single-phase multielement Ni42-x Cu8 Cox Mn37 Ga13(8≤x≤12)alloys by performing thermomechanical training.However,anomalous dependence ...Significant two-way shape memory effect(TWSME)was achieved in single crystals of single-phase multielement Ni42-x Cu8 Cox Mn37 Ga13(8≤x≤12)alloys by performing thermomechanical training.However,anomalous dependence of the martensitic transformation temperature span on Co content was observed.Before training,quite a narrow temperature span of the martensitic transformation,nearly independent of the Co content,was observed in all single crystals.After training the temperature span was still narrow for 8≤x≤10.9 but was obviously expanded for 10.9<x≤12.High-resolution transmission electron microscopy revealed that at the atomic scale,there exists incommensurate modulated structure in the single phase single crystals,as evidenced by nonperiodic satellite spots in the selected area electronic diffraction patterns.Moreover,the modulated wave vector of the satellite spots was increased by higher Co contents.Combining first principal calculations it was considered that the incommensurate modulated structure originates from the formation of Co-Co pairs.After training arrays of ordered dislocations with the same Burgers vector were introduced for 8≤x≤10.9 but the network of dislocations was formed for 10.9<x≤12.Based on analysis of transmission electron microscopy,geometric phase,thermodynamics,and Landau theory,it was considered that the austenite/martensite phase interface was pinned by the network of dislocations,expanding the temperature span of the martensitic transformation.This work supplies new insights for understanding the microstructure and martensitic transformation of Ni-Mn-Ga-based alloys.展开更多
The intimate host-anion interactions will regulate thermodynamics and kinetics in the self-assembly of cationic cages mimicking biological counterparts.Herein,we report construction and transformation of three Pd(Ⅱ)-...The intimate host-anion interactions will regulate thermodynamics and kinetics in the self-assembly of cationic cages mimicking biological counterparts.Herein,we report construction and transformation of three Pd(Ⅱ)-based metal-organic cages(MOCs)depending on different anions.Stoichiometric conversions of the lantern-shaped MOC-34 into either octahedral MOC-35 or tricapped trigonal prism MOC-36 are induced by BF_(4)^(–)or NO_(3)^(–),respectively.MOC-36 is kinetically favored and can undergo quantitative conversion to the thermodynamically preferred MOC-35 upon heating,accelerated by excess BF_(4)^(–)to motivate dissociative dynamics of Pd-vertices and lower activation barrier of cage transformation.The vip encapsulation behaviors of MOC-35 and MOC-36 have also been tested.These results manifest a significance of host-anion dynamics beyond complementary anion template,shedding light on the understanding of intricate anion recognition in nature.展开更多
Based on Joseph Schumpeter’s theory of“creative destruction,”we constructed a multi-sectoral endogenous growth model that integrates the agriculture,manufacturing,and service sectors.Employing numerical simulation,...Based on Joseph Schumpeter’s theory of“creative destruction,”we constructed a multi-sectoral endogenous growth model that integrates the agriculture,manufacturing,and service sectors.Employing numerical simulation,we investigated the dynamic influence of technological innovation on the industrial structural transformation in two key aspects:the level of innovation and the research and development(R&D)efficiency within industries.Our findings indicate that technological innovation plays a pivotal role in advancing industrial structural transformation.Enhancements in both the level of innovation and R&D efficiency within industries are instrumental in fostering industrial structural transformation.Specifically,the enhancements in the level of innovation or R&D efficiency within the agricultural sector hasten its transition toward the manufacturing sector,while such enhancement within the manufacturing sector expedites its transition toward the service sector.However,such enhancements within the service sector tend to decelerate the transition from manufacturing to service.In light of this,it is essential to harness technological innovation to enhance the level of innovation and R&D efficiency in industries to facilitate the transition of traditional industries into high-value-added and emerging ones.Meanwhile,tailored technological innovation strategies should be implemented to boost a balanced industrial structural transformation within industries.展开更多
The structured low-rank model for parallel magnetic resonance(MR)imaging can efficiently reconstruct MR images with limited auto-calibration signals.To improve the reconstruction quality of MR images,we integrate the ...The structured low-rank model for parallel magnetic resonance(MR)imaging can efficiently reconstruct MR images with limited auto-calibration signals.To improve the reconstruction quality of MR images,we integrate the joint sparsity and sparsifying transform learning(JTL)into the simultaneous auto-calibrating and k-space estimation(SAKE)structured low-rank model,named JTLSAKE.The alternate direction method of multipliers is exploited to solve the resulting optimization problem,and the optimized gradient method is used to improve the convergence speed.In addition,a graphics processing unit is used to accelerate the proposed algorithm.The experimental results on four in vivo human datasets demonstrate that the reconstruction quality of the proposed algorithm is comparable to that of JTL-based low-rank modeling of local k-space neighborhoods with parallel imaging(JTL-PLORAKS),and the proposed algorithm is 46 times faster than the JTL-PLORAKS,requiring only 4 s to reconstruct a 200×200 pixels MR image with 8 channels.展开更多
The layeredδ-MnO_(2)(dMO)is an excellent cathode material for rechargeable aqueous zinc-ion batteries owing to its large interlayer distance(~0.7 nm),high capacity,and low cost;however,such cathodes suffer from struc...The layeredδ-MnO_(2)(dMO)is an excellent cathode material for rechargeable aqueous zinc-ion batteries owing to its large interlayer distance(~0.7 nm),high capacity,and low cost;however,such cathodes suffer from structural degradation during the long-term cycling process,leading to capacity fading.In this study,a Co-doped dMO composite with reduced graphene oxide(GC-dMO)is developed using a simple cost-effective hydrothermal method.The degree of disorderness increases owing to the hetero-atom doping and graphene oxide composites.It is demonstrated that layered dMO and GC-dMO undergo a structural transition from K-birnessite to the Zn-buserite phase upon the first discharge,which enhances the intercalation of Zn^(2+)ions,H_(2)O molecules in the layered structure.The GC-dMO cathode exhibits an excellent capacity of 302 mAh g^(-1)at a current density of 100 mAg^(-1)after 100 cycles as compared with the dMO cathode(159 mAhg^(-1)).The excellent electrochemical performance of the GC-dMO cathode owing to Co-doping and graphene oxide sheets enhances the interlayer gap and disorderness,and maintains structural stability,which facilitates the easy reverse intercalation and de-intercalation of Zn^(2+)ions and H_(2)O molecules.Therefore,GC-dMO is a promising cathode material for large-scale aqueous ZIBs.展开更多
The character of structural changes in the surface layer of titanium carbide （TiC） with Ni-Cr alloy binder was investigated theoretically and experimentally after electron-beam treatment of the material surface. The...The character of structural changes in the surface layer of titanium carbide （TiC） with Ni-Cr alloy binder was investigated theoretically and experimentally after electron-beam treatment of the material surface. The thermal influence of the electron-beam irradiation on the surface layer microstructure of the composite fine-grained material was mathematically analyzed. Quantitative estimations of the depth of the zone in microstructural phase transformations were carried out. The microstructure and concentration profile of Ti distribution in the metallic binder over the cross section of the surface layer with microstructural phase transformations after electron-pulse treatment of the hard metal surface were experimentally investigated.展开更多
A new kind of polytriazoleimide containing bisphenyl-l,2,3-triazole （BPT） was synthesized by copper-catalyzed 1,3-dipolar cycloaddition of azides and alkynes （CuAAC） and polycondensation. The thermal stability and...A new kind of polytriazoleimide containing bisphenyl-l,2,3-triazole （BPT） was synthesized by copper-catalyzed 1,3-dipolar cycloaddition of azides and alkynes （CuAAC） and polycondensation. The thermal stability and degradation mechanism of the polytriazoleimide were investigated. The results show that the structure of BPT in polytriazoleimide transforms to phenylindole after thermal treatment, accompanying the release of NE.展开更多
The oxidation behavior of three biodiesels of different origins,viz.rapeseed oil derived biodiesel,soybean oil derived biodiesel and waste oil based biodiesel,were tested on an oxidation tester.The chemical compositio...The oxidation behavior of three biodiesels of different origins,viz.rapeseed oil derived biodiesel,soybean oil derived biodiesel and waste oil based biodiesel,were tested on an oxidation tester.The chemical compositions of the biodiesels were characterized by gas chromatography.Thereafter,the structural transformation of fatty acid methyl ester(FAME)of the biodiesels was analyzed by an infrared spectrometer and an ultraviolet absorption spectrometer.The results demonstrated that the oxidation behavior of biodiesels of different origins was closely related to the composition and distribution of FAMEs.Higher concentration of unsaturated FAME with multi-double bonds exhibited poorer oxidation resistance.Furthermore,cis-trans isomerization transformation occurred in the unsaturated FAME molecules and conjugated double-bond produced during the oxidation process of biodiesel.Greater cis-trans variations corresponded to deeper oxidation degree.The higher the content of unsaturated FAME with multi-double bonds in a biodiesel,the more the conjugated double bonds was formed.展开更多
The synergy effect of alloy elements in bimetallic clusters can be used to tune the chemical and physical properties. Research on the influences of alloy concentration and distribution on the frozen structure of bimet...The synergy effect of alloy elements in bimetallic clusters can be used to tune the chemical and physical properties. Research on the influences of alloy concentration and distribution on the frozen structure of bimetallic clusters plays a key rolc in exploring new structural materials. In this paper, we study the influence of Ag concentration on the frozen structure of the （AgCo）561 cluster by using molecular dynamics simulation with a general embedded atom method. The results indicate that tt^e structure and chemical ordering of the （AgCo）561 cluster are strongly related to Ag concentration. Hcp-icosahedron structural transformation in the frozen （CoAg）561 cluster can be induced by changing Ag concentration. The chemical ordering also transforms to Janus-like Co Ag from core-shell Co-Ag.展开更多
A mixture of Ni and Fe oxides is among the most commonly active catalysts for the oxygen evolution reaction(OER)during the water oxidation process.In particular,Ni oxide incorporated with even a small amount of Fe lea...A mixture of Ni and Fe oxides is among the most commonly active catalysts for the oxygen evolution reaction(OER)during the water oxidation process.In particular,Ni oxide incorporated with even a small amount of Fe leads to substantively enhanced OER activity.However,the critical role of Fe species during the electrocatalytic process is still under evaluation.Herein,we report nickel(oxy)hydroxide incorporated with Fe through the surface reconstruction of a bimetallic metal-organic framework(NiFe-MOF)during the water oxidation process.The spectroscopic investigations with theoretical calculations reveal the critical role of Fe in promoting the formation of highly oxidized Ni^(4+),which directly correlates with an enhanced OER activity.Both the geometric and electronic structu res of the as-reconstructed Ni_(1-x)Fe_(x)OOH electrocatalysts can be delicately tuned by the Ni-Fe ratio of the bimetallic NiFe-MOF,further affecting the catalytic activity.As a result,the Ni_(1-x)Fe_(x)OOH derived from Ni_(0.9)Fe_(0.1)-MOF delivers low overpotentials of 260 mV at 10 mA cm^(-2)and 400 mV at 300 mA cm^(-2).展开更多
In this paper,we performed an empirical study on the TFP effect of structural transformation based on panel data of economic growth in 169 countries across the world.Our findings are threefold:First,structural transfo...In this paper,we performed an empirical study on the TFP effect of structural transformation based on panel data of economic growth in 169 countries across the world.Our findings are threefold:First,structural transformation has an inverted U-shaped effect on TFP.When the degree of structural transformation is on the left side of the inflection point,structural transformation is conducive to softening industrial structure and inducing TFP;when the degree of structural transformation is on the right side of the inflection point,structural transformation will induce industrial hollowing out and inhibit TFP.Second,since the reform and opening up program was launched in 1978,China’s structural transformation has evolved from the stage of adaptation to the stage of strategic adjustment with an increasingly evident trend towards a service-based economy,but structural transformation remains on the left side of the inflection point of the inverted U-shaped curve,i.e.the TFP effect of structural transformation is positive.Third,TFP improvement lies at the heart of high-quality development.In pursuing high-quality development,China should lower growth rate expectations,attach greater importance to supply-side structural reforms,and accelerate structural transformation to promote TFP improvement.展开更多
The prolongation structure methodologies of Wahlquist-Estabrook [H.D. Wahlquist and F.B. Estabrook, J. Math. Phys. 16 （1975） 1] for nonlinear differential equations are applied to a more general set of coupled integ...The prolongation structure methodologies of Wahlquist-Estabrook [H.D. Wahlquist and F.B. Estabrook, J. Math. Phys. 16 （1975） 1] for nonlinear differential equations are applied to a more general set of coupled integrable dispersionless system. Based on the obtained prolongation structure, a Lie-Algebra valued connection of a closed ideal of exterior differential forms related to the above system is constructed. A Lie-Algebra representation of some hidden structural symmetries of the previous system, its Biicklund transformation using the Riccati form of the linear eigenvalue problem and their general corresponding Lax-representation are derived. In the wake of the previous results, we extend the above prolongation scheme to higher-dimensional systems from which a new （2 ＋ 1）-dimensional coupled integrable dispersionless system is unveiled along with its inverse scattering formulation, which applications are straightforward in nonlinear optics where additional propagating dimension deserves some attention.展开更多
An energy model for the structure transformation of pile-ups of grain boundary dislocations(GBD)at the triple-junction of the grain boundary of ultrafine-grain materials was proposed.The energy of the pile-up of the G...An energy model for the structure transformation of pile-ups of grain boundary dislocations(GBD)at the triple-junction of the grain boundary of ultrafine-grain materials was proposed.The energy of the pile-up of the GBD in the system was calculated by the energy model,the critical geometric and mechanical conditions for the structure transformation of head dislocation of the pile-up were analyzed,and the influence of the number density of the dislocations and the angle between Burgers vectors of two decomposed dislocations on the transformation mode of head dislocation was discussed.The results show when the GBD is accumulated at triple junction,the head dislocation of the GBD is decomposed into two Burgers vectors of these dislocations unless the angle between the two vectors is less than 90°,and the increase of applied external stress can reduce the energy barrier of the dislocation decomposition.The mechanism that the ultrafine-grained metal material has both high strength and plasticity owing to the structure transformation of the pile-up of the GBD at the triple junction of the grain boundary is revealed.展开更多
Fe100-xPtx(x=30at.%-60at.%) nanocomposite films were deposited on natural-oxidized Si(100) substrates by magnetron sputtering. The as-deposited films were annealed between 373 and 1073 K. In situ X-ray diffraction sho...Fe100-xPtx(x=30at.%-60at.%) nanocomposite films were deposited on natural-oxidized Si(100) substrates by magnetron sputtering. The as-deposited films were annealed between 373 and 1073 K. In situ X-ray diffraction shows that the FePt nanocomposite films undergo a phase transformation from a disordered FCC phase to an ordered L10 phase between 673 and 773 K. The coercivity is 306 kA·m-1 whiles the average grain sizes is about 10 nm in the optimized FePt alloy film sample annealed at 673 K. The adjustable coercivity and fine grain size suggest that this FePt nanocomposites system is suitable as recording media at extremely high areal density.展开更多
A rare porous zinc-organic framework with ultrahigh thermal stability over 500℃ was obtained, which exhibits a CaF2-type topology formed by 8-connected tetranuclear Zn4 clusters and 4-connected phosphonocarboxylate l...A rare porous zinc-organic framework with ultrahigh thermal stability over 500℃ was obtained, which exhibits a CaF2-type topology formed by 8-connected tetranuclear Zn4 clusters and 4-connected phosphonocarboxylate ligands. Interestingly, the similar reactions to the 2 zinc-organic framework but in the absence of H2 O or by the replacement of Zn2＋with Co2＋can yield three different 3 D cluster-based frameworks but with the same CaF2-type topology.展开更多
基金This study was supported by:The Late-Stage Support Program of the National Social Science Fund of China“Supply-Side Structural Reform and the Dual Structural Transformation of China's Economy”(Grant No.22FJLB009)The National Natural Science Fund of China for Young Scholars“The Dual Structural Transformation of China’s Economy:A Theoretical Analysis and Empirical Test Based on the Supply-Side Structural Reform”(Grant No.71703056).
文摘Occupational structural transformation is a common pattern during the steady growth of GDP per capita in major economies worldwide.In recent years,there has been a decline in the employment share of goods occupation and an increase in service occupation within the Chinese manufacturing industry,presenting a trend of occupational structural transformation and rapid development of service-oriented manufacturing.It is an important driving force and typical performance of the high-end,intelligent,and green development of the manufacturing industry.As a strategic general technology which leads the new round of technological revolution and industrial transformation,artificial intelligence(AI)has become a new fundamental force to accelerate the occupational structural transformation and service-oriented manufacturing development in China.Thus,this paper establishes a dynamic general equilibrium model with AI technology and occupational heterogeneity,showing the endogenous mechanism of occupational structural transformation.We find that when AI technology is biased towards goods occupation,and the elasticity of substitution between goods occupation and service occupation is less than 1,then AI will drive the transformation of occupational structure from goods to service within the manufacturing sector,increase the proportion of service-oriented manufacturing,improve labor productivity of manufacturing relative to service and stabilize the real output share of manufacturing.Promoting deeper integration of different occupations,intensifying R&D in AI technology and reducing labor mobility barriers between occupations can effectively accelerate the occupational structural transformation and industrial structural upgrading.We use theoretical analysis and numerical simulation method to show the theoretical mechanism by which AI affects occupational structural transformation and industrial structural transformation from a macroeconomic perspective,and put forward policy implications on how to promote the service-oriented manufacturing development and accelerate the construction of modern industrial system through AI innovation.
基金Project supported by the National Natural Science Foundation of China(Grant No.12261072)。
文摘The widespread popularization and application of laser technology have provided a powerful tool for a deeper understanding of the material world and given birth to several emerging research fields.This study mainly focuses on the following three key aspects.First,the classical ensemble method is adopted to conduct a comprehensive and in-depth analysis of two-dimensional(2D)matter–wave pulses in Bose–Fermi mixed gases(including linear and nonlinear pulses).Second,under the strict constraints of unitary systems,a coupled Kd V equation is successfully derived,and the prolongation structure theory is skillfully used to carry out detailed calculations and analyses on this equation.Thus,the prolongation algebra of this equation is accurately determined,and the corresponding Lax pair is rigorously derived.Finally,based on the carefully obtained Lax pair from the prolongation structure theory,the soliton solutions of this equation are further analyzed in depth,and intuitive images of each soliton solution are carefully drawn.This lays a solid foundation for subsequent detailed research on these soliton characteristics and provides great convenience.
基金supported by the Yuxiu Innovation Project of NCUT(Grant No.2024NCUTYXCX211).
文摘Purpose–This paper aims to provide a comprehensive analysis of the strategic adjustments in China’s transportation structure,with a particular focus on the pivotal role of railway freight and its integration into the modern logistics system.It seeks to address the need for a more nuanced understanding of the“road to rail”policy,emphasizing the importance of intermodal collaboration and service of fragmented market demands.Design/methodology/approach–The study employs a transport economics perspective to evaluate the achievements and shortcomings of China’s transportation structure optimization.It bases its assessment of the current state of railway freight logistics,multi-modal transportation and the broader implications for the transportation service market on data analysis.The methodology includes a review of existing policies,an examination of industry practices and a comparative analysis with global trends in railway logistics.Findings–The research underscores the importance of focusing on the development of non-bulk materials,noting the insufficiency in the development of China’s rail multi-modal transportation and highlighting the instructive value of successful cases in open-top container road-rail intermodal transportation.The study posits that the railway sector must enhance cooperation with other market entities,aligning with the lead enterprises in the logistics chain that are characterized by speed,high value and strong coordination capabilities,in order to better serve the transportation market.This approach moves away from a reliance on the railway’s own capabilities alone.Originality/value–This paper offers original insights into the transformation of railway freight in China,contributing to the body of knowledge on transportation economics and logistics.It provides valuable recommendations for policymakers and industry practitioners,emphasizing the strategic importance of railway logistics in the context of China’s economic development and intense competition in the supply chain.The value of the article lies in its comprehensive understanding of the complexities involved in the adjustment of transportation structures,providing direction for the market-oriented reform of China’s railway freight sector.
文摘Under the guidance of national policies,the“coal to gas”project has become one of the important measures to promote the transformation of energy structure in China.Foshan,an important industrial town in Guangdong province,the implementation of the“coal to gas”policy has demonstrated significance for the optimization of the national energy structure.Through the analysis of the change in Foshan’s energy consumption structure and the implementation of the policy,this paper found that there were some challenges in the policy implementation process,such as high economic cost,lagging infrastructure,low social acceptance,and lack of technical personnel.To address this,suggestions are put forward,including increasing financial subsidies,improving laws and regulations,promoting technological innovation,and encouraging social inclusion policies.These recommendations aim to provide guidance and reference for the remaining“coal to gas”projects and the development of clean energy.
基金support from the National Key Research and Development Program of China(Grant No.2021YFB3501402)the National Natural Science Foundation of China(Grant Nos.52250313 and 52121001)Yang Liu and Chen Si acknowledge financial support from the National Natural Science Foundation of China(Grant No.12274013).
文摘Significant two-way shape memory effect(TWSME)was achieved in single crystals of single-phase multielement Ni42-x Cu8 Cox Mn37 Ga13(8≤x≤12)alloys by performing thermomechanical training.However,anomalous dependence of the martensitic transformation temperature span on Co content was observed.Before training,quite a narrow temperature span of the martensitic transformation,nearly independent of the Co content,was observed in all single crystals.After training the temperature span was still narrow for 8≤x≤10.9 but was obviously expanded for 10.9<x≤12.High-resolution transmission electron microscopy revealed that at the atomic scale,there exists incommensurate modulated structure in the single phase single crystals,as evidenced by nonperiodic satellite spots in the selected area electronic diffraction patterns.Moreover,the modulated wave vector of the satellite spots was increased by higher Co contents.Combining first principal calculations it was considered that the incommensurate modulated structure originates from the formation of Co-Co pairs.After training arrays of ordered dislocations with the same Burgers vector were introduced for 8≤x≤10.9 but the network of dislocations was formed for 10.9<x≤12.Based on analysis of transmission electron microscopy,geometric phase,thermodynamics,and Landau theory,it was considered that the austenite/martensite phase interface was pinned by the network of dislocations,expanding the temperature span of the martensitic transformation.This work supplies new insights for understanding the microstructure and martensitic transformation of Ni-Mn-Ga-based alloys.
基金supported by the NKRD Program of China(No.2021YFA1500401)the National Natural Science Foundation of China(Nos.21821003,21890380)the LIRTP of Guangdong Pearl River Talents Program(No.2017BT01C161)。
文摘The intimate host-anion interactions will regulate thermodynamics and kinetics in the self-assembly of cationic cages mimicking biological counterparts.Herein,we report construction and transformation of three Pd(Ⅱ)-based metal-organic cages(MOCs)depending on different anions.Stoichiometric conversions of the lantern-shaped MOC-34 into either octahedral MOC-35 or tricapped trigonal prism MOC-36 are induced by BF_(4)^(–)or NO_(3)^(–),respectively.MOC-36 is kinetically favored and can undergo quantitative conversion to the thermodynamically preferred MOC-35 upon heating,accelerated by excess BF_(4)^(–)to motivate dissociative dynamics of Pd-vertices and lower activation barrier of cage transformation.The vip encapsulation behaviors of MOC-35 and MOC-36 have also been tested.These results manifest a significance of host-anion dynamics beyond complementary anion template,shedding light on the understanding of intricate anion recognition in nature.
基金supported by the project of the National Social Science Foundation of China entitled“Research on the Mechanism of Deep Integration of Modern Services Industry and Advanced Manufacturing Industry Driven by Digital Technology Innovation”(Project No.21BJY144).
文摘Based on Joseph Schumpeter’s theory of“creative destruction,”we constructed a multi-sectoral endogenous growth model that integrates the agriculture,manufacturing,and service sectors.Employing numerical simulation,we investigated the dynamic influence of technological innovation on the industrial structural transformation in two key aspects:the level of innovation and the research and development(R&D)efficiency within industries.Our findings indicate that technological innovation plays a pivotal role in advancing industrial structural transformation.Enhancements in both the level of innovation and R&D efficiency within industries are instrumental in fostering industrial structural transformation.Specifically,the enhancements in the level of innovation or R&D efficiency within the agricultural sector hasten its transition toward the manufacturing sector,while such enhancement within the manufacturing sector expedites its transition toward the service sector.However,such enhancements within the service sector tend to decelerate the transition from manufacturing to service.In light of this,it is essential to harness technological innovation to enhance the level of innovation and R&D efficiency in industries to facilitate the transition of traditional industries into high-value-added and emerging ones.Meanwhile,tailored technological innovation strategies should be implemented to boost a balanced industrial structural transformation within industries.
基金the Yunnan Fundamental Research Projects(No.202301AT070452)the National Natural Science Foundation of China(No.61861023)。
文摘The structured low-rank model for parallel magnetic resonance(MR)imaging can efficiently reconstruct MR images with limited auto-calibration signals.To improve the reconstruction quality of MR images,we integrate the joint sparsity and sparsifying transform learning(JTL)into the simultaneous auto-calibrating and k-space estimation(SAKE)structured low-rank model,named JTLSAKE.The alternate direction method of multipliers is exploited to solve the resulting optimization problem,and the optimized gradient method is used to improve the convergence speed.In addition,a graphics processing unit is used to accelerate the proposed algorithm.The experimental results on four in vivo human datasets demonstrate that the reconstruction quality of the proposed algorithm is comparable to that of JTL-based low-rank modeling of local k-space neighborhoods with parallel imaging(JTL-PLORAKS),and the proposed algorithm is 46 times faster than the JTL-PLORAKS,requiring only 4 s to reconstruct a 200×200 pixels MR image with 8 channels.
基金supported by the National Research Foundation of Korea(NRF)grants funded by the Korean Government(NRF-2021R1A4A1030318,NRF-2022R1C1C1011386,NRF-2020M3H4A1A03084258)supported by the"Regional Innovation Strategy(RIS)"through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(MOE)(2021RIS-003)
文摘The layeredδ-MnO_(2)(dMO)is an excellent cathode material for rechargeable aqueous zinc-ion batteries owing to its large interlayer distance(~0.7 nm),high capacity,and low cost;however,such cathodes suffer from structural degradation during the long-term cycling process,leading to capacity fading.In this study,a Co-doped dMO composite with reduced graphene oxide(GC-dMO)is developed using a simple cost-effective hydrothermal method.The degree of disorderness increases owing to the hetero-atom doping and graphene oxide composites.It is demonstrated that layered dMO and GC-dMO undergo a structural transition from K-birnessite to the Zn-buserite phase upon the first discharge,which enhances the intercalation of Zn^(2+)ions,H_(2)O molecules in the layered structure.The GC-dMO cathode exhibits an excellent capacity of 302 mAh g^(-1)at a current density of 100 mAg^(-1)after 100 cycles as compared with the dMO cathode(159 mAhg^(-1)).The excellent electrochemical performance of the GC-dMO cathode owing to Co-doping and graphene oxide sheets enhances the interlayer gap and disorderness,and maintains structural stability,which facilitates the easy reverse intercalation and de-intercalation of Zn^(2+)ions and H_(2)O molecules.Therefore,GC-dMO is a promising cathode material for large-scale aqueous ZIBs.
文摘The character of structural changes in the surface layer of titanium carbide （TiC） with Ni-Cr alloy binder was investigated theoretically and experimentally after electron-beam treatment of the material surface. The thermal influence of the electron-beam irradiation on the surface layer microstructure of the composite fine-grained material was mathematically analyzed. Quantitative estimations of the depth of the zone in microstructural phase transformations were carried out. The microstructure and concentration profile of Ti distribution in the metallic binder over the cross section of the surface layer with microstructural phase transformations after electron-pulse treatment of the hard metal surface were experimentally investigated.
基金the financial support of Shanghai Leading Academic Discipline Project(No. B502)Fundamental Research Funds for the Central University
文摘A new kind of polytriazoleimide containing bisphenyl-l,2,3-triazole （BPT） was synthesized by copper-catalyzed 1,3-dipolar cycloaddition of azides and alkynes （CuAAC） and polycondensation. The thermal stability and degradation mechanism of the polytriazoleimide were investigated. The results show that the structure of BPT in polytriazoleimide transforms to phenylindole after thermal treatment, accompanying the release of NE.
基金the financial support from the National Natual Science Foundation of China(No.51375491)the Natural Science Foundation of Chongqing(Project No.2011JJA90020)the Science Foundation for Young Teachers of Logistical Engineering University
文摘The oxidation behavior of three biodiesels of different origins,viz.rapeseed oil derived biodiesel,soybean oil derived biodiesel and waste oil based biodiesel,were tested on an oxidation tester.The chemical compositions of the biodiesels were characterized by gas chromatography.Thereafter,the structural transformation of fatty acid methyl ester(FAME)of the biodiesels was analyzed by an infrared spectrometer and an ultraviolet absorption spectrometer.The results demonstrated that the oxidation behavior of biodiesels of different origins was closely related to the composition and distribution of FAMEs.Higher concentration of unsaturated FAME with multi-double bonds exhibited poorer oxidation resistance.Furthermore,cis-trans isomerization transformation occurred in the unsaturated FAME molecules and conjugated double-bond produced during the oxidation process of biodiesel.Greater cis-trans variations corresponded to deeper oxidation degree.The higher the content of unsaturated FAME with multi-double bonds in a biodiesel,the more the conjugated double bonds was formed.
基金supported by the Science Foundation of Chongqing Committee of Education of China (Grant No. KJ111206)the Fund of Chongqing University of Arts and Sciences (Grant No. Z2011RCYJ05)
文摘The synergy effect of alloy elements in bimetallic clusters can be used to tune the chemical and physical properties. Research on the influences of alloy concentration and distribution on the frozen structure of bimetallic clusters plays a key rolc in exploring new structural materials. In this paper, we study the influence of Ag concentration on the frozen structure of the （AgCo）561 cluster by using molecular dynamics simulation with a general embedded atom method. The results indicate that tt^e structure and chemical ordering of the （AgCo）561 cluster are strongly related to Ag concentration. Hcp-icosahedron structural transformation in the frozen （CoAg）561 cluster can be induced by changing Ag concentration. The chemical ordering also transforms to Janus-like Co Ag from core-shell Co-Ag.
基金supported by the National Natural Science Foundation of China(22105060)the Natural Science Foundation of Hebei Province(E2020205004)+1 种基金Funding from the Science Foundation of Hebei Normal University(L2020B13)the Science and Technology Project of Hebei Education Department(BJ2021028)。
文摘A mixture of Ni and Fe oxides is among the most commonly active catalysts for the oxygen evolution reaction(OER)during the water oxidation process.In particular,Ni oxide incorporated with even a small amount of Fe leads to substantively enhanced OER activity.However,the critical role of Fe species during the electrocatalytic process is still under evaluation.Herein,we report nickel(oxy)hydroxide incorporated with Fe through the surface reconstruction of a bimetallic metal-organic framework(NiFe-MOF)during the water oxidation process.The spectroscopic investigations with theoretical calculations reveal the critical role of Fe in promoting the formation of highly oxidized Ni^(4+),which directly correlates with an enhanced OER activity.Both the geometric and electronic structu res of the as-reconstructed Ni_(1-x)Fe_(x)OOH electrocatalysts can be delicately tuned by the Ni-Fe ratio of the bimetallic NiFe-MOF,further affecting the catalytic activity.As a result,the Ni_(1-x)Fe_(x)OOH derived from Ni_(0.9)Fe_(0.1)-MOF delivers low overpotentials of 260 mV at 10 mA cm^(-2)and 400 mV at 300 mA cm^(-2).
文摘In this paper,we performed an empirical study on the TFP effect of structural transformation based on panel data of economic growth in 169 countries across the world.Our findings are threefold:First,structural transformation has an inverted U-shaped effect on TFP.When the degree of structural transformation is on the left side of the inflection point,structural transformation is conducive to softening industrial structure and inducing TFP;when the degree of structural transformation is on the right side of the inflection point,structural transformation will induce industrial hollowing out and inhibit TFP.Second,since the reform and opening up program was launched in 1978,China’s structural transformation has evolved from the stage of adaptation to the stage of strategic adjustment with an increasingly evident trend towards a service-based economy,but structural transformation remains on the left side of the inflection point of the inverted U-shaped curve,i.e.the TFP effect of structural transformation is positive.Third,TFP improvement lies at the heart of high-quality development.In pursuing high-quality development,China should lower growth rate expectations,attach greater importance to supply-side structural reforms,and accelerate structural transformation to promote TFP improvement.
文摘The prolongation structure methodologies of Wahlquist-Estabrook [H.D. Wahlquist and F.B. Estabrook, J. Math. Phys. 16 （1975） 1] for nonlinear differential equations are applied to a more general set of coupled integrable dispersionless system. Based on the obtained prolongation structure, a Lie-Algebra valued connection of a closed ideal of exterior differential forms related to the above system is constructed. A Lie-Algebra representation of some hidden structural symmetries of the previous system, its Biicklund transformation using the Riccati form of the linear eigenvalue problem and their general corresponding Lax-representation are derived. In the wake of the previous results, we extend the above prolongation scheme to higher-dimensional systems from which a new （2 ＋ 1）-dimensional coupled integrable dispersionless system is unveiled along with its inverse scattering formulation, which applications are straightforward in nonlinear optics where additional propagating dimension deserves some attention.
基金financial supports from the National Natural Science Foundation of China(Nos.51161003,51561031)the Natural Science Foundation of Guangxi,China(No.2018GXNSFAA138150)。
文摘An energy model for the structure transformation of pile-ups of grain boundary dislocations(GBD)at the triple-junction of the grain boundary of ultrafine-grain materials was proposed.The energy of the pile-up of the GBD in the system was calculated by the energy model,the critical geometric and mechanical conditions for the structure transformation of head dislocation of the pile-up were analyzed,and the influence of the number density of the dislocations and the angle between Burgers vectors of two decomposed dislocations on the transformation mode of head dislocation was discussed.The results show when the GBD is accumulated at triple junction,the head dislocation of the GBD is decomposed into two Burgers vectors of these dislocations unless the angle between the two vectors is less than 90°,and the increase of applied external stress can reduce the energy barrier of the dislocation decomposition.The mechanism that the ultrafine-grained metal material has both high strength and plasticity owing to the structure transformation of the pile-up of the GBD at the triple junction of the grain boundary is revealed.
基金This work was financially supported by the National Science Fund for Distinguished Young Scholars and the National Natural Science Foundation of China (No. 50325209, 50232030).
文摘Fe100-xPtx(x=30at.%-60at.%) nanocomposite films were deposited on natural-oxidized Si(100) substrates by magnetron sputtering. The as-deposited films were annealed between 373 and 1073 K. In situ X-ray diffraction shows that the FePt nanocomposite films undergo a phase transformation from a disordered FCC phase to an ordered L10 phase between 673 and 773 K. The coercivity is 306 kA·m-1 whiles the average grain sizes is about 10 nm in the optimized FePt alloy film sample annealed at 673 K. The adjustable coercivity and fine grain size suggest that this FePt nanocomposites system is suitable as recording media at extremely high areal density.
基金financially supported by the National Natural Science Foundations of China (Nos. 21303018, 21371033, and 21401195)the Natural Science Foundation for Young Scholars of Fujian Province (No. 2015J05041)Projects from State Key Laboratory of Structural Chemistry of China (Nos. 20150001 and 20160020)
文摘A rare porous zinc-organic framework with ultrahigh thermal stability over 500℃ was obtained, which exhibits a CaF2-type topology formed by 8-connected tetranuclear Zn4 clusters and 4-connected phosphonocarboxylate ligands. Interestingly, the similar reactions to the 2 zinc-organic framework but in the absence of H2 O or by the replacement of Zn2＋with Co2＋can yield three different 3 D cluster-based frameworks but with the same CaF2-type topology.
