Using the typical characteristics of multi-layered marine and continental transitional gas reservoirs as a basis,a model is developed to predict the related well production rate.This model relies on the fractal theory...Using the typical characteristics of multi-layered marine and continental transitional gas reservoirs as a basis,a model is developed to predict the related well production rate.This model relies on the fractal theory of tortuous capillary bundles and can take into account multiple gas flow mechanisms at the micrometer and nanometer scales,as well as the flow characteristics in different types of thin layers(tight sandstone gas,shale gas,and coalbed gas).Moreover,a source-sink function concept and a pressure drop superposition principle are utilized to introduce a coupled flow model in the reservoir.A semi-analytical solution for the production rate is obtained using a matrix iteration method.A specific well is selected for fitting dynamic production data,and the calculation results show that the tight sandstone has the highest gas production per unit thickness compared with the other types of reservoirs.Moreover,desorption and diffusion of coalbed gas and shale gas can significantly contribute to gas production,and the daily production of these two gases decreases rapidly with decreasing reservoir pressure.Interestingly,the gas production from fractures exhibits an approximately U-shaped distribution,indicating the need to optimize the spacing between clusters during hydraulic fracturing to reduce the area of overlapping fracture control.The coal matrix water saturation significantly affects the coalbed gas production,with higher water saturation leading to lower production.展开更多
Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transiti...Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transition in a Hubbard model by using the dynamical mean-field theory and introduce the local quantum state fidelity to depict the Mott metal–insulator transition. The local quantum state fidelity provides a convenient approach to determining the critical point of the Mott transition. Additionally, it presents a consistent description of the two distinct forms of the Mott transition points.展开更多
The pursuit of improved quality of life standards has significantly influenced the contemporary mining model in the 21st century.This era is witnessing an unprecedented transformation driven by pressing concerns relat...The pursuit of improved quality of life standards has significantly influenced the contemporary mining model in the 21st century.This era is witnessing an unprecedented transformation driven by pressing concerns related to sustainability,climate change,the just energy transition,dynamic operating environments,and complex social challenges.Such transitions present both opportunities and obstacles.The aim of this study is to provide an extensive literature review on energy transition to identify the challenges and strategies associated with navigating transformations in energy systems.Understanding these transformations is particularly critical in the face of the severe consequences of global warming,where an accelerated energy transition is viewed as a universal remedy.Adopting a socio-technological systems perspective,specifically through the application of Actor Network Theory(ANT),this research provides a theoretical foundation while categorising challenges into five distinct domains and outlining strategies across these different dimensions.These insights are specifically tailored for emerging market countries to effectively navigate energy transition while fostering the development of resilient societies.Furthermore,our findings highlight that energy transition encompasses more than a mere technological shift;it entails fundamental changes in various systemic socio-economic imperatives.Through focusing on the role of social structures in transitions,this study makes a significant and innovative contribution to ANT,which has historically been criticised for its limited acknowledgement of social structures.Consequently,we propose an emerging market energy transition framework,which not only addresses technological aspects,but also integrates social considerations.This framework paves the way for future research and exploration of energy transition dynamics.The outcomes of this study offer valuable insights to policymakers,researchers,and practitioners engaged in the mining industry,enabling them to comprehend the multifaceted challenges involved and providing practical strategies for effective resolution.Through incorporating the social dimension into the analysis,we enhance the understanding of the complex nature of energy system transformations,facilitating a more holistic approach towards achieving sustainable and resilient energy transitions in emerging markets and beyond.展开更多
Objective Overweight and obesity prevalence has increased in low-income countries.This study systematically reviewed the obesity trend,disparities,and prevention and control efforts in Nepal.Methods We searched PubMed...Objective Overweight and obesity prevalence has increased in low-income countries.This study systematically reviewed the obesity trend,disparities,and prevention and control efforts in Nepal.Methods We searched PubMed and Google Scholar for articles and reports published between January 1,2004 and December 31,2022.Additional information on National policies and programs related to obesity prevention was retrieved from governmental websites and consultation with relevant experts.Overweight and obesity were defined using the World Health Organization body mass index cut points.Thirty-two studies and reports were included.Results Overall,overweight and obesity rates increased in all groups in Nepal although nationally representative data remained limited.The combined overweight and obesity(OW/OB)and obesity rates in women aged 15-49 years increased from 8.5%to 22.2%and from 0.9%to 5.1%between 2006 and 2016,respectively.OW/OB and obesity rates in men were 17.1%and 2.5%based on data from the 2016 Demographic and Health Survey.OW/OB rate in under-five children increased from 0.6%to 2.8%between 2006 and 2016.Obesity rates for school-age(5-9 years)boys and girls in 2016 were 2.4%and 2.8%,respectively,and were 1.1%and 1.4%for male and female adolescents aged 10-19 years,respectively.OW/OB prevalence was much higher among women,residents in urban areas and central provinces,and in higher socioeconomic status groups.Projected prevalence of OW/OB and obesity for 2030 in adults aged 15-49 was 44.7%and 8.3%,respectively,while it was 2.2%for OW/OB in preschool children.Policies and direct interventions that specifically focused on obesity prevention and control are limited.Conclusions OW/OB prevalence in Nepal has increased during the past 1.8 decades,disproportionately affecting population groups.Existing interventions mostly focused on undernutrition with some indirect implications for obesity prevention.In the future,Nepal needs to develop population-based programs for obesity prevention.展开更多
The world is facing dramatic challenges related to environmental sustainability at an accelerating pace.In this context,the field of economic geography(EG)has been playing an important role in understanding both the s...The world is facing dramatic challenges related to environmental sustainability at an accelerating pace.In this context,the field of economic geography(EG)has been playing an important role in understanding both the socioeconomic and technological dimensions of these challenges,as it deals with a variety of complementary notions and perspectives.Departing from this lens,our aim is to explore a conceptual framework that can help us to understand environmental changes relating to multi-dimensional territorial development,notably in eco-nomic contexts where inequality is high,and stratification based on hierarchies regulate social and economic life.Based on the territory concept,we propose the original notion of a hierarchical regional innovation system(HRIS)that emphasises the pervasive role of hierarchies(powers)in regional innovation systems and illustrate its value with evidence and case studies from extant literature on sustainability transitions.The HRIS can help us understand and promote development paths considering the contribution of inclusive eco-innovations(another original conceptual amalgam).Through some empirical cases from other studies in low-carbon transitions,we show the application of the HRIS(and inclusive eco-innovation)framework.In conclusion,we provide incen-tives to explore new regional innovation systems,alongside the HRIS,adapted to different regions worldwide and centred on the inclusiveness of people and places.展开更多
Purpose-The aim of this work is to research and design an expert diagnosis system for rail vehicle driven by data mechanism models.Design/methodology/approach-The expert diagnosis system utilizes statistical and deep ...Purpose-The aim of this work is to research and design an expert diagnosis system for rail vehicle driven by data mechanism models.Design/methodology/approach-The expert diagnosis system utilizes statistical and deep learning methods to model the real-time status and historical data features of rail vehicle.Based on data mechanism models,it predicts the lifespan of key components,evaluates the health status of the vehicle and achieves intelligent monitoring and diagnosis of rail vehicle.Findings-The actual operation effect of this system shows that it has improved the intelligent level of the rail vehicle monitoring system,which helps operators to monitor the operation of vehicle online,predict potential risks and faults of vehicle and ensure the smooth and safe operation of vehicle.Originality/value-This system improves the efficiency of rail vehicle operation,scheduling and maintenance through intelligent monitoring and diagnosis of rail vehicle.展开更多
This paper is concerned with a modified transitional Korteweg-de Vries equation ut+f(t)u2ux+uxxx=0, (x,t)∈R+×R+with initial value u(x,0)=g(x)∈H4(R+)and inhomogeneous boundary value u(0,t)=Q(t)∈C2([ 0,∞ )). Un...This paper is concerned with a modified transitional Korteweg-de Vries equation ut+f(t)u2ux+uxxx=0, (x,t)∈R+×R+with initial value u(x,0)=g(x)∈H4(R+)and inhomogeneous boundary value u(0,t)=Q(t)∈C2([ 0,∞ )). Under the conditions either 1) f(t)≤0, f′(t)≥0or 2) f(t)≤−αwhere α>0, we prove the existence of a unique global classical solution.展开更多
The fabrication of Fe2O3-MnO2-Co2O3-CuO system ceramics, and the composite system ceramics of transitional metal oxides-cordierite and transitional metal oxides-kaolinit are presented in this work. The research was ca...The fabrication of Fe2O3-MnO2-Co2O3-CuO system ceramics, and the composite system ceramics of transitional metal oxides-cordierite and transitional metal oxides-kaolinit are presented in this work. The research was carried out with the main attention to the infrared emissivity in the band of 8 similar to 14 mu m at room temperature, the microstructure of the ceramics and the relation between them. High infrared emissivities exceeding 0.9 in the band of 8 similar to 14 mu m at room temperature were gained in the transitional metal oxide ceramics and the composite system ceramics. It is suggested that the formation of inverse spinels and partially inverse spinels, such as Fe3O4, CoFe2O4, CuFe2O4 and CuMn2O4, is beneficial to the enhancement of the infrared emissivity of the transitional metal oxide ceramics. The transitional metal oxides play an important role in determining the infrared emissivity of the composite system ceramics.展开更多
Economic new normal and the change of industry environment, market environment and competition environment boost the liquor industry to conduct the transitional development. By analyzing the status quo and the motivat...Economic new normal and the change of industry environment, market environment and competition environment boost the liquor industry to conduct the transitional development. By analyzing the status quo and the motivation of transformation of the liquor industry, the liquor business ecosystem is constructed in this paper. And the path of transitional development of liquor industry is proposed based on the type division of liquor business ecosystem. Then we give some countermeasures and suggestions to improve transitional development of liquor industry from the aspect of liquor business ecosystem, government regulation and the transformation of liquor making company.展开更多
Rising sea-levels in tectonically active epicontinental basins often lead to varied depositional settings and palaeogeography, mostly influenced by the net accommodation resulting from mutual interference of the exten...Rising sea-levels in tectonically active epicontinental basins often lead to varied depositional settings and palaeogeography, mostly influenced by the net accommodation resulting from mutual interference of the extent and nature of landward encroachment by the sea and the net sedimentation. The Cenomanian Nimar Sandstone Formation, Bagh Group, Narmada rift basin, uniquely portrays the effect of sea-level rise within an intra-cratonic setting and attributes to the corresponding palaeogeographic changes in west-central India. An integrated sedimentological–sequence-stratigraphic study of the broadly fining-upward Nimar Sandstone Formation(thickness~ 20–30 m) depicts the actual nature of changeover from a fluvial to a marine-dominated transitional depositional setting. Detailed sedimentological study reveals total seventeen facies, grouped in five facies associations, viz., the channel-fill facies association(FA-1), the overbank facies association(FA-2), the fluvial-dominated fluvio-tidal facies association(FA-3), the tide-dominated fluvio-tidal facies association(FA-4), and the shoreface facies association(FA-5). Overall facies architecture indicates a west-to-eastward marine encroachment, resulting in stacking of three distinct palaeo-depositional conditions:(i) an initial fluvial system with channel and overbank, changing into a tideinfluenced fluvial bay-head delta in the inner estuary, followed by(ii) marine encroachment leading to a tidedominated central estuary with inter-to sub-tidal settings, and finally,(iii) with further intense marine encroachments, a wave-reworked open shore condition in the outer estuary zone. The overall fining-up succession with a systematic change from fluvial to marine-dominated depositional systems points to a landward shift of the shoreline, signifying a major transgressive event correlated to the Cenomanian global sea-level rise. Characteristic stratal stacking patterns point to four coarsening-and fining-up hemicycles, embedded within the major transgressive succession. These high-frequency cycles attest to the varied interplay of sedimentation, tectonics and sea-level changes, and the resultant net accommodations. A palaeogeographic model is proposed based on the high-frequency transgressive–regressive hemicycles, which envisages the evolution of the depositional environments in relation to the Cenomanian eustatic rise in the intra-cratonic riftogenic fluvio-marine transitional basinal setup.展开更多
A mapping function between the Reynolds-averaged Navier-Stokes mean flow variables and transition intermittency factor is constructed by fully connected artificial neural network(ANN),which replaces the governing equa...A mapping function between the Reynolds-averaged Navier-Stokes mean flow variables and transition intermittency factor is constructed by fully connected artificial neural network(ANN),which replaces the governing equation of the intermittency factor in transition-predictive Spalart-Allmaras(SA)-γmodel.By taking SA-γmodel as the benchmark,the present ANN model is trained at two airfoils with various angles of attack,Mach numbers and Reynolds numbers,and tested with unseen airfoils in different flow states.The a posteriori tests manifest that the mean pressure coefficient,skin friction coefficient,size of laminar separation bubble,mean streamwise velocity,Reynolds shear stress and lift/drag/moment coefficient from the present two-way coupling ANN model almost coincide with those from the benchmark SA-γmodel.Furthermore,the ANN model proves to exhibit a higher calculation efficiency and better convergence quality than traditional SA-γmodel.展开更多
The clay mineralogy of 28 sandy-muddy transitional beach(SMT-Beach)sediments and surrounding mountain river sediments along the coasts of southeastern China was systematically investigated to reveal the sediment sourc...The clay mineralogy of 28 sandy-muddy transitional beach(SMT-Beach)sediments and surrounding mountain river sediments along the coasts of southeastern China was systematically investigated to reveal the sediment source-to-sink process variations of such beaches and their morphological indications.The results show that the clay mineral assemblages of these SMT-Beaches mainly comprise of almost equal illite(~30%),kaolinite(~28%),chlorite(~22%),and smectite(~20%)contents.From the surrounding mountain rivers to the SMT-Beaches,clay mineral assemblages show distinct spatial changes characterized by a large decrease(~40%)in kaolinite,whereas the other three clay minerals present relative increases,especially clear for smectite.The muddy sediment sources of SMT-Beaches inferred from the clay mineralogy are mainly derived from nearby mountain rivers coupled with long-distance transport and penetration of the Changjiang River.The sandy sediments of these beaches are predominantly sourced from nearby mountain rivers,the weathering products of surrounding rocks in both mainland and island environments,and erosion of the“Old Red Sand”and“Red Soil Platform”.However,the sandy sediment sources of the SMT-Beaches are largely reduced because of the remarkable decrease in the river fluvial supply associated with intensive human activities such as dam construction and coastal reclamation.Subsequently,the sandy sections of SMT-Beaches present clear erosion and have revealed by both time series remote sensing images and a compilation of published literature.In contrast,the muddy sediment supply of SMT-Beaches is temporarily stable and relatively constant,resulting in the landward migration of the mudflats with relative transgression or accumulation.These findings highlight that the natural evolution processes of SMT-Beaches have been greatly reshaped by intensive human activities.展开更多
As a major solution to climate change,the low-carbon transition of energy systems has received growing attention in the past decade.This paper presents a bibliometric review of the literature on the low-carbon transit...As a major solution to climate change,the low-carbon transition of energy systems has received growing attention in the past decade.This paper presents a bibliometric review of the literature on the low-carbon transition of energy systems from an engineering management perspective.First,the definition and boundaries of the energy system transition are clarified,covering transformation of the energy structure,decarbonization of fossil fuel utilization,and improvement in energy efficiency.Second,a systematic search of the related literature and a bibliometric analysis are conducted to reveal the research trends.It is found that the number of related publications has been growing exponentially during the past decade,with researchers from China,the United Kingdom,the United States,Germany,and the Netherlands comprising the majority of authors.Related studies with interdisciplinary characteristics appear in journals focusing on energy engineering,environmental science,and social science related to energy issues.Four major research themes are identified by clustering the existing literature:(1)low-carbon transition pathways with different spatiotemporal scales and transition constraints;(2)low-carbon technology diffusion with a focus on renewable energy technologies,pollution control technologies,and other technologies facilitating the energy transition;(3)infrastructure network planning for energy systems covering various sectors and regions;and(4)transition-driving mechanisms from the political,economic,social,and natural perspectives.These four topics play distinct but mutually supportive roles in facilitating the low-carbon transition of energy systems,and require more in-depth research on designing resilient low-carbon transition pathways with coordinated goals,promoting low-carbon technologies with cost-effective and reliable infrastructure network deployment,and balancing multi-level risks in various systems.Finally,business models,nongovernment actors,energy justice,deep decarbonization,and zero-energy buildings are recognized as emerging hot topics.展开更多
An ultrafast pump-probe spectroscopy system combined with a cryogenic diamond anvil cell(DAC) instrument is developed to investigate the photo-excitation dynamic properties of condensed materials under low temperature...An ultrafast pump-probe spectroscopy system combined with a cryogenic diamond anvil cell(DAC) instrument is developed to investigate the photo-excitation dynamic properties of condensed materials under low temperature and high pressure(LTHP) conditions.The ultrafast dynamics study is performed on Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi-2212) thin film under LTHP conditions.The superconducting(SC) phase transition has been observed by analyzing the ultrafast dynamics of Bi-2212 as a function of pressure and temperature.Our results suggest that the pump-probe spectroscopy system combined with a cryogenic DAC instrument is an effective method to study the physical mechanism of condensed matter physics at extreme conditions,especially for the SC phase transition.展开更多
A Janus particle has two distinct areas on its surface.Denoting the two areas as P(patch)and N(nonpatch),when two particles come close to each other,the strength of the PP interaction is usually different from that of...A Janus particle has two distinct areas on its surface.Denoting the two areas as P(patch)and N(nonpatch),when two particles come close to each other,the strength of the PP interaction is usually different from that of the NN interaction.Recently the interplay between a rotational-symmetry-breaking continuous phase transition and percolation has been explored for an equilibrium system of asymmetrically interacting(i.e.,attractive PP interaction,zero NN and PN interactions)Janus disks on the triangular lattice.By Monte Carlo simulation and finite-size scaling analysis,in this work we study an equilibrium system of symmetrically interacting(i.e.,attractive PP and NN interactions with the same strength,zero PN interaction)Janus disks on the same lattice.By definition,the phase diagram in the T-θplane is symmetric for systems with patch sizesθbelow and above 90°.We determine the phase diagram and compare it with that of the asymmetric system.Similar to the latter system,for 60°<θ<90°,a rotational-symmetry-breaking continuous phase transition and an anisotropic percolation transition are found in the symmetric system,though the transition points in the two systems are quite different.Phase crossover curves are found to be different,e.g.,a continuous varying crossover line extends betweenθ=0°and 90°for the symmetric model;and in the range 0°<θ≤30°,along the crossover lines of the two models,the trends of 1/T vs.θare opposite in the two systems.We understand the latter by analytically solving the models with two particles in 0°<θ≤30°.These results are helpful for understanding close-packed systems of Janus disks with more complex interactions.展开更多
Massive data from observations,experiments and simulations of dynamical models in scientific and engineering fields make it desirable for data-driven methods to extract basic laws of these models.We present a novel me...Massive data from observations,experiments and simulations of dynamical models in scientific and engineering fields make it desirable for data-driven methods to extract basic laws of these models.We present a novel method to identify such high dimensional stochastic dynamical systems that are perturbed by a non-Gaussianα-stable Lévy noise.More explicitly,firstly a machine learning framework to solve the sparse regression problem is established to grasp the drift terms through one of nonlocal Kramers–Moyal formulas.Then the jump measure and intensity of the noise are disposed by the relationship with statistical characteristics of the process.Three examples are then given to demonstrate the feasibility.This approach proposes an effective way to understand the complex phenomena of systems under non-Gaussian fluctuations and illuminates some insights into the exploration for further typical dynamical indicators such as the maximum likelihood transition path or mean exit time of these stochastic systems.展开更多
We construct a mapped bilayer quantum Hall system to realize the proposal that two nearly flatbands have opposite Chern numbers.For the C=±1 case,the two Landau levels of the bilayer experience opposite magnetic ...We construct a mapped bilayer quantum Hall system to realize the proposal that two nearly flatbands have opposite Chern numbers.For the C=±1 case,the two Landau levels of the bilayer experience opposite magnetic fields.We consider a mapped bilayer quantum Hall system at total fillingν_(t)=1/2+1/2where the intralayer interaction is repulsive and the interlayer interaction is attractive.We take exact diagonalization(ED)calculations on a torus to study the phase transition when the separation distance d/l_(B)is driven.The critical point at d_(c)/l_(B)=0.68 is characterized by a collapse of degeneracy and a crossing of energy levels.In the region d/l_(B)<d_(c)/l_(B),the states of each level are highly degenerate.The pair-correlation function indicates electrons with opposite pseudo-spins are strong correlated at r=0.We find an exciton stripe phase composed of bound pairs.The ferromagnetic ground state is destroyed by the strong effective attractive potential.An electron composite-Fermion(eCF)and a hole composite Fermion(hCF)are tightly bound.In the region d/lB>d_(c)/l_(B),a crossover from the d→d_(c)limit to the large d limit is observed.The electron and hole composite Fermion liquids(CFL)are realized by composite Fermions(CF)which attach opposite fluxes,respectively.展开更多
Based on Halliday’s systemic functional grammar,especially the ideational function,this research aims at disclosing the hidden ideologies and values of the seemingly objective news reports on China’s COVID-19 polici...Based on Halliday’s systemic functional grammar,especially the ideational function,this research aims at disclosing the hidden ideologies and values of the seemingly objective news reports on China’s COVID-19 policies in The Economist.Transitivity,voice,and nominalization are the major analytical subjects.After China lifted the zero-COVID policy,western media began criticizing China’s lack of data sharing,with some misinformation and misleading reports.The denouncement of inertness and reluctance to fight against the pandemic disclaim the Chinese government’s efforts and depreciate China’s image.China is portrayed as the villain and destroyer of people’s health worldwide.Meanwhile,they also hold a hesitant attitude toward China’s diplomacy.The re-engaging with foreign countries and travel restrictions have been described as imprudent and rushed actions.They also consider China as the fuse of contradiction in the United Nations.What is overt is their view of breaking up China.展开更多
Public transport system has been a means of addressing transportation challenges in urban areas, such as traffic congestion, traffic jam and long travel time in cities worldwide. Transportation in Africa is unique in ...Public transport system has been a means of addressing transportation challenges in urban areas, such as traffic congestion, traffic jam and long travel time in cities worldwide. Transportation in Africa is unique in that it has the least developed public transport systems in the world, while also being one of the fastest urbanizing continents. Bus Rapid Transit being one of the public transport systems was introduced in Africa in 2008 as a means to provide solution on urban transportation challenges. Despite of public transport being the main means of transport in African developing countries, there have been a number of challenges that affects efficiency of performance of the system and makes its users uncomfortable. Therefore, the study aimed at exploring the setbacks or challenges associated with operation and performance of the BRT system in the African developing countries and address them. The study employed mixed methods research design that integrates both qualitative and quantitative data collection methods and analysis. The study findings reveal that, there is an improvement on the perspectives of the commuters on public transport after introduction of BRT system. However, some challenges such as long waiting time, passengers overcrowding during peak hours, as well as safety and security can slowly change the perspective of the commuters. Therefore, to address these challenges it is recommended to reduce the long waiting time and improve accessibility by introduction of passenger information displays (bus information system) and automated fare collection system;reduce travel time by introduction of bus priority signal;and improve safety and security by introduction of signage and CCTV Camera within the bus and bus stops.展开更多
文摘Using the typical characteristics of multi-layered marine and continental transitional gas reservoirs as a basis,a model is developed to predict the related well production rate.This model relies on the fractal theory of tortuous capillary bundles and can take into account multiple gas flow mechanisms at the micrometer and nanometer scales,as well as the flow characteristics in different types of thin layers(tight sandstone gas,shale gas,and coalbed gas).Moreover,a source-sink function concept and a pressure drop superposition principle are utilized to introduce a coupled flow model in the reservoir.A semi-analytical solution for the production rate is obtained using a matrix iteration method.A specific well is selected for fitting dynamic production data,and the calculation results show that the tight sandstone has the highest gas production per unit thickness compared with the other types of reservoirs.Moreover,desorption and diffusion of coalbed gas and shale gas can significantly contribute to gas production,and the daily production of these two gases decreases rapidly with decreasing reservoir pressure.Interestingly,the gas production from fractures exhibits an approximately U-shaped distribution,indicating the need to optimize the spacing between clusters during hydraulic fracturing to reduce the area of overlapping fracture control.The coal matrix water saturation significantly affects the coalbed gas production,with higher water saturation leading to lower production.
基金Project supported by the Scientific Research Foundation for Youth Academic Talent of Inner Mongolia University (Grant No.1000023112101/010)the Fundamental Research Funds for the Central Universities of China (Grant No.JN200208)+2 种基金supported by the National Natural Science Foundation of China (Grant No.11474023)supported by the National Key Research and Development Program of China (Grant No.2021YFA1401803)the National Natural Science Foundation of China (Grant Nos.11974051 and 11734002)。
文摘Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transition in a Hubbard model by using the dynamical mean-field theory and introduce the local quantum state fidelity to depict the Mott metal–insulator transition. The local quantum state fidelity provides a convenient approach to determining the critical point of the Mott transition. Additionally, it presents a consistent description of the two distinct forms of the Mott transition points.
基金University of the Witwatersrand Additional funding is from the DSI-National Research Foundation(NRF)Thuthuka Grant(Grant UID:121973)and DSI-NRF CIMERA.
文摘The pursuit of improved quality of life standards has significantly influenced the contemporary mining model in the 21st century.This era is witnessing an unprecedented transformation driven by pressing concerns related to sustainability,climate change,the just energy transition,dynamic operating environments,and complex social challenges.Such transitions present both opportunities and obstacles.The aim of this study is to provide an extensive literature review on energy transition to identify the challenges and strategies associated with navigating transformations in energy systems.Understanding these transformations is particularly critical in the face of the severe consequences of global warming,where an accelerated energy transition is viewed as a universal remedy.Adopting a socio-technological systems perspective,specifically through the application of Actor Network Theory(ANT),this research provides a theoretical foundation while categorising challenges into five distinct domains and outlining strategies across these different dimensions.These insights are specifically tailored for emerging market countries to effectively navigate energy transition while fostering the development of resilient societies.Furthermore,our findings highlight that energy transition encompasses more than a mere technological shift;it entails fundamental changes in various systemic socio-economic imperatives.Through focusing on the role of social structures in transitions,this study makes a significant and innovative contribution to ANT,which has historically been criticised for its limited acknowledgement of social structures.Consequently,we propose an emerging market energy transition framework,which not only addresses technological aspects,but also integrates social considerations.This framework paves the way for future research and exploration of energy transition dynamics.The outcomes of this study offer valuable insights to policymakers,researchers,and practitioners engaged in the mining industry,enabling them to comprehend the multifaceted challenges involved and providing practical strategies for effective resolution.Through incorporating the social dimension into the analysis,we enhance the understanding of the complex nature of energy system transformations,facilitating a more holistic approach towards achieving sustainable and resilient energy transitions in emerging markets and beyond.
基金This study was funded by the research grants from the Key Research and Development Program of Shaanxi Province of China(2022SF-125 and 2021ZDLSF02-14).
文摘Objective Overweight and obesity prevalence has increased in low-income countries.This study systematically reviewed the obesity trend,disparities,and prevention and control efforts in Nepal.Methods We searched PubMed and Google Scholar for articles and reports published between January 1,2004 and December 31,2022.Additional information on National policies and programs related to obesity prevention was retrieved from governmental websites and consultation with relevant experts.Overweight and obesity were defined using the World Health Organization body mass index cut points.Thirty-two studies and reports were included.Results Overall,overweight and obesity rates increased in all groups in Nepal although nationally representative data remained limited.The combined overweight and obesity(OW/OB)and obesity rates in women aged 15-49 years increased from 8.5%to 22.2%and from 0.9%to 5.1%between 2006 and 2016,respectively.OW/OB and obesity rates in men were 17.1%and 2.5%based on data from the 2016 Demographic and Health Survey.OW/OB rate in under-five children increased from 0.6%to 2.8%between 2006 and 2016.Obesity rates for school-age(5-9 years)boys and girls in 2016 were 2.4%and 2.8%,respectively,and were 1.1%and 1.4%for male and female adolescents aged 10-19 years,respectively.OW/OB prevalence was much higher among women,residents in urban areas and central provinces,and in higher socioeconomic status groups.Projected prevalence of OW/OB and obesity for 2030 in adults aged 15-49 was 44.7%and 8.3%,respectively,while it was 2.2%for OW/OB in preschool children.Policies and direct interventions that specifically focused on obesity prevention and control are limited.Conclusions OW/OB prevalence in Nepal has increased during the past 1.8 decades,disproportionately affecting population groups.Existing interventions mostly focused on undernutrition with some indirect implications for obesity prevention.In the future,Nepal needs to develop population-based programs for obesity prevention.
基金support from the Centre of Studies in Geography and Spatial Planning(CEGOT)funded by national funds through the Foundation for Science and Technology(FCT)under the reference UIDB/04084/2020.
文摘The world is facing dramatic challenges related to environmental sustainability at an accelerating pace.In this context,the field of economic geography(EG)has been playing an important role in understanding both the socioeconomic and technological dimensions of these challenges,as it deals with a variety of complementary notions and perspectives.Departing from this lens,our aim is to explore a conceptual framework that can help us to understand environmental changes relating to multi-dimensional territorial development,notably in eco-nomic contexts where inequality is high,and stratification based on hierarchies regulate social and economic life.Based on the territory concept,we propose the original notion of a hierarchical regional innovation system(HRIS)that emphasises the pervasive role of hierarchies(powers)in regional innovation systems and illustrate its value with evidence and case studies from extant literature on sustainability transitions.The HRIS can help us understand and promote development paths considering the contribution of inclusive eco-innovations(another original conceptual amalgam).Through some empirical cases from other studies in low-carbon transitions,we show the application of the HRIS(and inclusive eco-innovation)framework.In conclusion,we provide incen-tives to explore new regional innovation systems,alongside the HRIS,adapted to different regions worldwide and centred on the inclusiveness of people and places.
基金supported by Hunan Province Enterprise Technology Innovation and Entrepreneurship Team Support Program Project,Hunan Province Science and Technology Innovation Leading Talent Project[2023RC1088]Hunan Province Science and Technology Talent Support Project[2023TJ-Z10].
文摘Purpose-The aim of this work is to research and design an expert diagnosis system for rail vehicle driven by data mechanism models.Design/methodology/approach-The expert diagnosis system utilizes statistical and deep learning methods to model the real-time status and historical data features of rail vehicle.Based on data mechanism models,it predicts the lifespan of key components,evaluates the health status of the vehicle and achieves intelligent monitoring and diagnosis of rail vehicle.Findings-The actual operation effect of this system shows that it has improved the intelligent level of the rail vehicle monitoring system,which helps operators to monitor the operation of vehicle online,predict potential risks and faults of vehicle and ensure the smooth and safe operation of vehicle.Originality/value-This system improves the efficiency of rail vehicle operation,scheduling and maintenance through intelligent monitoring and diagnosis of rail vehicle.
文摘This paper is concerned with a modified transitional Korteweg-de Vries equation ut+f(t)u2ux+uxxx=0, (x,t)∈R+×R+with initial value u(x,0)=g(x)∈H4(R+)and inhomogeneous boundary value u(0,t)=Q(t)∈C2([ 0,∞ )). Under the conditions either 1) f(t)≤0, f′(t)≥0or 2) f(t)≤−αwhere α>0, we prove the existence of a unique global classical solution.
基金The research is supported by the Foundation for Excellent Youth of Wuhan Science and Technology Commission and Opening Foundation of Stae Key Laboratory of Advanced Technology for Materials Synthesis and Process of Wuhan University of Technology.
文摘The fabrication of Fe2O3-MnO2-Co2O3-CuO system ceramics, and the composite system ceramics of transitional metal oxides-cordierite and transitional metal oxides-kaolinit are presented in this work. The research was carried out with the main attention to the infrared emissivity in the band of 8 similar to 14 mu m at room temperature, the microstructure of the ceramics and the relation between them. High infrared emissivities exceeding 0.9 in the band of 8 similar to 14 mu m at room temperature were gained in the transitional metal oxide ceramics and the composite system ceramics. It is suggested that the formation of inverse spinels and partially inverse spinels, such as Fe3O4, CoFe2O4, CuFe2O4 and CuMn2O4, is beneficial to the enhancement of the infrared emissivity of the transitional metal oxide ceramics. The transitional metal oxides play an important role in determining the infrared emissivity of the composite system ceramics.
基金supported by the philosophy and social sciences planning project of Sichuan province(Grant No.SC14E047)the bidding project of Key Research Base of Philosophy and Social Sciences in Sichuan Province-Research Center for Sichuan Liquor Industry Development(Grant No.CJZB15-02)Luzhou Laojiao Co.,Ltd Scientific Research Scholarship Program(Grant No.15ljsk04)
文摘Economic new normal and the change of industry environment, market environment and competition environment boost the liquor industry to conduct the transitional development. By analyzing the status quo and the motivation of transformation of the liquor industry, the liquor business ecosystem is constructed in this paper. And the path of transitional development of liquor industry is proposed based on the type division of liquor business ecosystem. Then we give some countermeasures and suggestions to improve transitional development of liquor industry from the aspect of liquor business ecosystem, government regulation and the transformation of liquor making company.
基金Authors are thankful to the Ministry of Earth Sciences,Government of India,for financial support in the form of Extra-Mural Research Project(Ref.No.Mo ES/P.O.(Geo)/142/2017)。
文摘Rising sea-levels in tectonically active epicontinental basins often lead to varied depositional settings and palaeogeography, mostly influenced by the net accommodation resulting from mutual interference of the extent and nature of landward encroachment by the sea and the net sedimentation. The Cenomanian Nimar Sandstone Formation, Bagh Group, Narmada rift basin, uniquely portrays the effect of sea-level rise within an intra-cratonic setting and attributes to the corresponding palaeogeographic changes in west-central India. An integrated sedimentological–sequence-stratigraphic study of the broadly fining-upward Nimar Sandstone Formation(thickness~ 20–30 m) depicts the actual nature of changeover from a fluvial to a marine-dominated transitional depositional setting. Detailed sedimentological study reveals total seventeen facies, grouped in five facies associations, viz., the channel-fill facies association(FA-1), the overbank facies association(FA-2), the fluvial-dominated fluvio-tidal facies association(FA-3), the tide-dominated fluvio-tidal facies association(FA-4), and the shoreface facies association(FA-5). Overall facies architecture indicates a west-to-eastward marine encroachment, resulting in stacking of three distinct palaeo-depositional conditions:(i) an initial fluvial system with channel and overbank, changing into a tideinfluenced fluvial bay-head delta in the inner estuary, followed by(ii) marine encroachment leading to a tidedominated central estuary with inter-to sub-tidal settings, and finally,(iii) with further intense marine encroachments, a wave-reworked open shore condition in the outer estuary zone. The overall fining-up succession with a systematic change from fluvial to marine-dominated depositional systems points to a landward shift of the shoreline, signifying a major transgressive event correlated to the Cenomanian global sea-level rise. Characteristic stratal stacking patterns point to four coarsening-and fining-up hemicycles, embedded within the major transgressive succession. These high-frequency cycles attest to the varied interplay of sedimentation, tectonics and sea-level changes, and the resultant net accommodations. A palaeogeographic model is proposed based on the high-frequency transgressive–regressive hemicycles, which envisages the evolution of the depositional environments in relation to the Cenomanian eustatic rise in the intra-cratonic riftogenic fluvio-marine transitional basinal setup.
基金the financial supports provided by the National Natural Science Foundation of China(Nos.91852112 and 11988102)。
文摘A mapping function between the Reynolds-averaged Navier-Stokes mean flow variables and transition intermittency factor is constructed by fully connected artificial neural network(ANN),which replaces the governing equation of the intermittency factor in transition-predictive Spalart-Allmaras(SA)-γmodel.By taking SA-γmodel as the benchmark,the present ANN model is trained at two airfoils with various angles of attack,Mach numbers and Reynolds numbers,and tested with unseen airfoils in different flow states.The a posteriori tests manifest that the mean pressure coefficient,skin friction coefficient,size of laminar separation bubble,mean streamwise velocity,Reynolds shear stress and lift/drag/moment coefficient from the present two-way coupling ANN model almost coincide with those from the benchmark SA-γmodel.Furthermore,the ANN model proves to exhibit a higher calculation efficiency and better convergence quality than traditional SA-γmodel.
基金The National Natural Science Foundation of China under contract Nos 41930538,42076211 and 42076058the Scientific Research Foundation of the Third Institute of Oceanography,Ministry of Natural Resources under contract Nos 2022017 and 2019006the China Postdoctoral Science Foundation under contract No.2019M652248.
文摘The clay mineralogy of 28 sandy-muddy transitional beach(SMT-Beach)sediments and surrounding mountain river sediments along the coasts of southeastern China was systematically investigated to reveal the sediment source-to-sink process variations of such beaches and their morphological indications.The results show that the clay mineral assemblages of these SMT-Beaches mainly comprise of almost equal illite(~30%),kaolinite(~28%),chlorite(~22%),and smectite(~20%)contents.From the surrounding mountain rivers to the SMT-Beaches,clay mineral assemblages show distinct spatial changes characterized by a large decrease(~40%)in kaolinite,whereas the other three clay minerals present relative increases,especially clear for smectite.The muddy sediment sources of SMT-Beaches inferred from the clay mineralogy are mainly derived from nearby mountain rivers coupled with long-distance transport and penetration of the Changjiang River.The sandy sediments of these beaches are predominantly sourced from nearby mountain rivers,the weathering products of surrounding rocks in both mainland and island environments,and erosion of the“Old Red Sand”and“Red Soil Platform”.However,the sandy sediment sources of the SMT-Beaches are largely reduced because of the remarkable decrease in the river fluvial supply associated with intensive human activities such as dam construction and coastal reclamation.Subsequently,the sandy sections of SMT-Beaches present clear erosion and have revealed by both time series remote sensing images and a compilation of published literature.In contrast,the muddy sediment supply of SMT-Beaches is temporarily stable and relatively constant,resulting in the landward migration of the mudflats with relative transgression or accumulation.These findings highlight that the natural evolution processes of SMT-Beaches have been greatly reshaped by intensive human activities.
基金the financial support provided by the National Natural Science Foundation of China(71934007 and 72004228)。
文摘As a major solution to climate change,the low-carbon transition of energy systems has received growing attention in the past decade.This paper presents a bibliometric review of the literature on the low-carbon transition of energy systems from an engineering management perspective.First,the definition and boundaries of the energy system transition are clarified,covering transformation of the energy structure,decarbonization of fossil fuel utilization,and improvement in energy efficiency.Second,a systematic search of the related literature and a bibliometric analysis are conducted to reveal the research trends.It is found that the number of related publications has been growing exponentially during the past decade,with researchers from China,the United Kingdom,the United States,Germany,and the Netherlands comprising the majority of authors.Related studies with interdisciplinary characteristics appear in journals focusing on energy engineering,environmental science,and social science related to energy issues.Four major research themes are identified by clustering the existing literature:(1)low-carbon transition pathways with different spatiotemporal scales and transition constraints;(2)low-carbon technology diffusion with a focus on renewable energy technologies,pollution control technologies,and other technologies facilitating the energy transition;(3)infrastructure network planning for energy systems covering various sectors and regions;and(4)transition-driving mechanisms from the political,economic,social,and natural perspectives.These four topics play distinct but mutually supportive roles in facilitating the low-carbon transition of energy systems,and require more in-depth research on designing resilient low-carbon transition pathways with coordinated goals,promoting low-carbon technologies with cost-effective and reliable infrastructure network deployment,and balancing multi-level risks in various systems.Finally,business models,nongovernment actors,energy justice,deep decarbonization,and zero-energy buildings are recognized as emerging hot topics.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12274168 and 12074141)。
文摘An ultrafast pump-probe spectroscopy system combined with a cryogenic diamond anvil cell(DAC) instrument is developed to investigate the photo-excitation dynamic properties of condensed materials under low temperature and high pressure(LTHP) conditions.The ultrafast dynamics study is performed on Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi-2212) thin film under LTHP conditions.The superconducting(SC) phase transition has been observed by analyzing the ultrafast dynamics of Bi-2212 as a function of pressure and temperature.Our results suggest that the pump-probe spectroscopy system combined with a cryogenic DAC instrument is an effective method to study the physical mechanism of condensed matter physics at extreme conditions,especially for the SC phase transition.
基金supported by the National Natural Science Foundation of China(Grant No.11905001)。
文摘A Janus particle has two distinct areas on its surface.Denoting the two areas as P(patch)and N(nonpatch),when two particles come close to each other,the strength of the PP interaction is usually different from that of the NN interaction.Recently the interplay between a rotational-symmetry-breaking continuous phase transition and percolation has been explored for an equilibrium system of asymmetrically interacting(i.e.,attractive PP interaction,zero NN and PN interactions)Janus disks on the triangular lattice.By Monte Carlo simulation and finite-size scaling analysis,in this work we study an equilibrium system of symmetrically interacting(i.e.,attractive PP and NN interactions with the same strength,zero PN interaction)Janus disks on the same lattice.By definition,the phase diagram in the T-θplane is symmetric for systems with patch sizesθbelow and above 90°.We determine the phase diagram and compare it with that of the asymmetric system.Similar to the latter system,for 60°<θ<90°,a rotational-symmetry-breaking continuous phase transition and an anisotropic percolation transition are found in the symmetric system,though the transition points in the two systems are quite different.Phase crossover curves are found to be different,e.g.,a continuous varying crossover line extends betweenθ=0°and 90°for the symmetric model;and in the range 0°<θ≤30°,along the crossover lines of the two models,the trends of 1/T vs.θare opposite in the two systems.We understand the latter by analytically solving the models with two particles in 0°<θ≤30°.These results are helpful for understanding close-packed systems of Janus disks with more complex interactions.
基金the National Natural Science Foundation of China(Grant No.12172167)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Massive data from observations,experiments and simulations of dynamical models in scientific and engineering fields make it desirable for data-driven methods to extract basic laws of these models.We present a novel method to identify such high dimensional stochastic dynamical systems that are perturbed by a non-Gaussianα-stable Lévy noise.More explicitly,firstly a machine learning framework to solve the sparse regression problem is established to grasp the drift terms through one of nonlocal Kramers–Moyal formulas.Then the jump measure and intensity of the noise are disposed by the relationship with statistical characteristics of the process.Three examples are then given to demonstrate the feasibility.This approach proposes an effective way to understand the complex phenomena of systems under non-Gaussian fluctuations and illuminates some insights into the exploration for further typical dynamical indicators such as the maximum likelihood transition path or mean exit time of these stochastic systems.
文摘We construct a mapped bilayer quantum Hall system to realize the proposal that two nearly flatbands have opposite Chern numbers.For the C=±1 case,the two Landau levels of the bilayer experience opposite magnetic fields.We consider a mapped bilayer quantum Hall system at total fillingν_(t)=1/2+1/2where the intralayer interaction is repulsive and the interlayer interaction is attractive.We take exact diagonalization(ED)calculations on a torus to study the phase transition when the separation distance d/l_(B)is driven.The critical point at d_(c)/l_(B)=0.68 is characterized by a collapse of degeneracy and a crossing of energy levels.In the region d/l_(B)<d_(c)/l_(B),the states of each level are highly degenerate.The pair-correlation function indicates electrons with opposite pseudo-spins are strong correlated at r=0.We find an exciton stripe phase composed of bound pairs.The ferromagnetic ground state is destroyed by the strong effective attractive potential.An electron composite-Fermion(eCF)and a hole composite Fermion(hCF)are tightly bound.In the region d/lB>d_(c)/l_(B),a crossover from the d→d_(c)limit to the large d limit is observed.The electron and hole composite Fermion liquids(CFL)are realized by composite Fermions(CF)which attach opposite fluxes,respectively.
文摘Based on Halliday’s systemic functional grammar,especially the ideational function,this research aims at disclosing the hidden ideologies and values of the seemingly objective news reports on China’s COVID-19 policies in The Economist.Transitivity,voice,and nominalization are the major analytical subjects.After China lifted the zero-COVID policy,western media began criticizing China’s lack of data sharing,with some misinformation and misleading reports.The denouncement of inertness and reluctance to fight against the pandemic disclaim the Chinese government’s efforts and depreciate China’s image.China is portrayed as the villain and destroyer of people’s health worldwide.Meanwhile,they also hold a hesitant attitude toward China’s diplomacy.The re-engaging with foreign countries and travel restrictions have been described as imprudent and rushed actions.They also consider China as the fuse of contradiction in the United Nations.What is overt is their view of breaking up China.
文摘Public transport system has been a means of addressing transportation challenges in urban areas, such as traffic congestion, traffic jam and long travel time in cities worldwide. Transportation in Africa is unique in that it has the least developed public transport systems in the world, while also being one of the fastest urbanizing continents. Bus Rapid Transit being one of the public transport systems was introduced in Africa in 2008 as a means to provide solution on urban transportation challenges. Despite of public transport being the main means of transport in African developing countries, there have been a number of challenges that affects efficiency of performance of the system and makes its users uncomfortable. Therefore, the study aimed at exploring the setbacks or challenges associated with operation and performance of the BRT system in the African developing countries and address them. The study employed mixed methods research design that integrates both qualitative and quantitative data collection methods and analysis. The study findings reveal that, there is an improvement on the perspectives of the commuters on public transport after introduction of BRT system. However, some challenges such as long waiting time, passengers overcrowding during peak hours, as well as safety and security can slowly change the perspective of the commuters. Therefore, to address these challenges it is recommended to reduce the long waiting time and improve accessibility by introduction of passenger information displays (bus information system) and automated fare collection system;reduce travel time by introduction of bus priority signal;and improve safety and security by introduction of signage and CCTV Camera within the bus and bus stops.