Based on micro-survey data from 894 farmers in Sichuan Province,this study employs the Ordinary Least Squares(OLS),Two-Stage Least Squares(2SLS),mediating effect,and moderating effect models to comprehensively analyze...Based on micro-survey data from 894 farmers in Sichuan Province,this study employs the Ordinary Least Squares(OLS),Two-Stage Least Squares(2SLS),mediating effect,and moderating effect models to comprehensively analyze the mechanisms and effects of digital literacy in empowering farmers’common prosperity.Endogeneity and robustness are addressed using the Sobel test,the Bootstrap,and moderating effect plots.The findings indicate that first,after controlling for variables such as age,gender,and planting years,digital literacy significantly and positively influences the common prosperity of farmers at the 5%level;second,enhanced digital literacy promotes higher levels of technology adoption and information accumulation among farmers,thereby increasing the probability of achieving common prosperity.The mediating effects of technology adoption and information sharing account for 21.10%and 33.94%of the total effect,respectively;and third,the information environment and financial empowerment play positive moderation roles in the effect of digital literacy on farmers’common prosperity,with the moderation effects significant at the 1%and 10%levels,respectively.Therefore,we recommend policies that enhance the access of farmers to digital literacy training,strengthen rural digital infrastructure,establish integrated rural information-sharing platforms,and create an enabling environment for the adoption of digital technologies.展开更多
With the rapid development of China’s economy,the coordinated development of resident income and GDP has become an important indicator to measure local economic development.How to realize the synergistic growth of th...With the rapid development of China’s economy,the coordinated development of resident income and GDP has become an important indicator to measure local economic development.How to realize the synergistic growth of the two in the new era is of great significance for promoting the sustainable development of the local economy.Based on the theory of the coordinated development of resident income and GDP,this paper will take Shandong Province as an example to analyze the interaction between resident income growth and GDP,find out the influencing factors that restrict the coordinated development of resident income and GDP,and explore the impact of the coordinated development of resident income and GDP on local economic development.Finally,relevant policies will be studied.How to effectively increase residents’income,promote the sustainable and healthy development of the local economy,and put forward relevant suggestions to promote the coordinated development of residents’income and GDP.展开更多
The author’s combined numerical model consisting of a third generation shallow water wave model and a 3 D tide surge model with wave dependent surface wind stress were used to study the influence of waves on tide sur...The author’s combined numerical model consisting of a third generation shallow water wave model and a 3 D tide surge model with wave dependent surface wind stress were used to study the influence of waves on tide surge motion. For the typical weather case, in this study, the magnitude and mechanism of the influence of waves on tide surges in the Bohai Sea were revealed for the first time. The results showed that although consideration of the wave dependent surface wind stresses raise slightly the traditional surface wind stress, due to the accumulated effects, the computed results are improved on the whole. Storm level maximum modulation can reach 0.4 m. The results computed by the combined model agreed well with the measured data.展开更多
Throughout versatile metal compositions and unique structural characteristics,polynary metal atom catalysts(PACs)readily harness synergistic intermetallic effects,significantly boosting the catalytic performances.Thes...Throughout versatile metal compositions and unique structural characteristics,polynary metal atom catalysts(PACs)readily harness synergistic intermetallic effects,significantly boosting the catalytic performances.These catalysts are featured by favorable catalytic activity,stability and selectivity,offering avenues to tackle challenges in energy conversion,environmental protection and chemical synthesis.Nevertheless,an in-depth understanding and comprehensive summary of the structure-performance relationship for the emerging PACs remains elusive.This review embarks from the classification of PACs,delving further into the origins of catalytic activity and mechanisms underpinning performance enhancement.At the beginning,it outlines the fundamental concepts,preparation methods and accurate recognition of PACs.Subsequently,it centers on discussing the origins of activity,strategies for performance optimization,mechanisms of action,and application scenarios across diverse catalytic reactions.Moreover,the unexplored issues and future perspectives of PACs are proposed at the end,stating their pivotal roles in advancing green chemistry and the sustainable energy realm.This review overall aims to provide valuable insight and guidance for the preparation and application of PACs.展开更多
In recent years,supercritical CO_(2)flooding has become an effective method for developing lowpermeability reservoirs.In supercritical CO_(2)flooding different factors influence the mechanism of its displacement proce...In recent years,supercritical CO_(2)flooding has become an effective method for developing lowpermeability reservoirs.In supercritical CO_(2)flooding different factors influence the mechanism of its displacement process for oil recovery.Asynchronous injection-production modes can use supercritical CO_(2)to enhance oil recovery but may also worsen the injection capacity.Cores with high permeability have higher oil recovery rates and better injection capacity,however,gas channeling occurs.Supercritical CO_(2)flooding has a higher oil recovery at high pressure levels,which delays the occurrence of gas channeling.Conversely,gas injection has lower displacement efficiency but better injection capacity at the high water cut stage.This study analyzes the displacement characteristics of supercritical CO_(2)flooding with a series of experiments under different injection and production parameters.Experimental results show that the gas breakthrough stage has the fastest oil production and the supercritical CO_(2)injection capacity variation tendency is closely related to the gas-oil ratio.Further experiments show that higher injection rates represent significant ultimate oil recovery and injection index,providing a good reference for developing low-permeability reservoirs.展开更多
The development of cancer is a complex process that requires the participation of many factors,including mutations in genes, regulation of signaling pathways, disruption of homeostasis, and failure of self-monitoring ...The development of cancer is a complex process that requires the participation of many factors,including mutations in genes, regulation of signaling pathways, disruption of homeostasis, and failure of self-monitoring mechanisms. Sufficient evidence has展开更多
The study of pressure stimulated current(PSC)changes of rocks is significant to monitor dynamic disasters in mines and rock masses.The existing studies focus on change laws and mechanism of currents generated under th...The study of pressure stimulated current(PSC)changes of rocks is significant to monitor dynamic disasters in mines and rock masses.The existing studies focus on change laws and mechanism of currents generated under the loading of rocks.An electrical and mechanics test system was established in this paper to explore the impacts of loading rates on PSCs.The results indicated that PSC curves of different rocks had different change laws under low/high loading rates.When the loading rate was relatively low,PSC curves firstly changed gently and then increased exponentially.Under high loading rates,PSC curves experienced the rapid increase stage,gentle increase stage and sudden change stage.The compressive strength could greatly affect the peak PSC in case of rock failure.The loading rate was a key factor in average PSC.Under low loading rates,the variations of PSCs conformed to the damage charge model of fracture mechanics,while they did not at the fracture moment.Under high loading rates,the PSCs at low stress didn’t fit the model due to the stress impact effects.The experimental results could provide theoretical basis for the influence of loading rates on PSCs.展开更多
[Objective] The research aimed to study the possible mechanism of terrain effect on cold-flow snowstorm.[Method] By using the meso-scale numerical model(WRF),a cold-flow snowstorm weather process in Shandong Peninsula...[Objective] The research aimed to study the possible mechanism of terrain effect on cold-flow snowstorm.[Method] By using the meso-scale numerical model(WRF),a cold-flow snowstorm weather process in Shandong Peninsula was carried out numerical simulation and terrain sensitivity contrast test.The possible reason of terrain effect on falling zone and strength of snowstorm was deeply analyzed from water vapor,thermodynamic field and so on.[Result] The mountain terrain in Shandong Peninsula had great influences on falling zone and strength of cold-flow snowstorm.The strength of snowstorm obviously increased,and the snowfall center obviously moved northward.The main reason was that terrain caused the low-level wind field convergence and vertical movement in the troposphere strengthened.Then,the spatial distribution of water vapor and snow water content in the cold-flow snowstorm process obviously changed.So,the whole snowstorm process was affected.[Conclusion] The mountain terrain in Shandong Peninsula was the important element which needed to be focused on considering in the forecast analysis of cold-flow snowstorm weather process.展开更多
Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and or...Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and orientations of the stress can be classified into three types. The corresponding physical conditions for each type of the loop are deduced based on the principle of minimal energy. The equation of the critical stress is derived, which can judge whether the loops show hysteresis or not. Numerical calculations suggest that except for the magnitude of the mechanical stress, the relative orientation of the stress is also an important factor to tune the exchange bias effect.展开更多
In this paper, the relation between Asian summer monsoon circulation and sea surface temperature anomalies over equatorial central-eastern Pacific is investigated by using a global spectral model. This model has nine ...In this paper, the relation between Asian summer monsoon circulation and sea surface temperature anomalies over equatorial central-eastern Pacific is investigated by using a global spectral model. This model has nine layers in the vertical and the model variables are represented in the horizontal as truncated expansions of the surface spherical harmonics with rhomboidal truncation at wave number 15. The model involves comparatively complete physical processes and parameterizations with mountains.Using the above model, two experimental schemes are designed, namely control case and anomalous sea surface temperature case. The above two schemes are respectively integrated for forty days and the simulated results are obtained from the last 30-day averaged simulations.The simulations show that positive SST anomalies over equatorial central-eastern Pacific weakens Indian monsoon circulation,decreases precipitation in Indian sub-continent whereas it intensifies East Asian monsoon circulation and increases precipitation in East Asian area. All these results reflect the characteristics of Asian summer monsoon during the El Nino period. In this paper, SST anomalies over equatorial central-eastern Pacific have a direct influence on the intensity and position of subtropical high via the wave train over Northern Hemisphere, which is similar to that suggested by Nitta(1987) and the wave train over Southern Hemisphere has an influence on the intensity of Muscarene high and Australia high resulting in affecting cross equatorial flow. As a result, atmospheric interior heat sources and sinks are redistributed because of the change of cross equatorial flow. And the response of atmosphere to the new heat source and sink has a significant influence on Asian summer monsoon.展开更多
On the basis of combing domestic and foreign related literature and research practice,the influence mechanism of the construction of new liberal arts was analyzed,and the fundamental tasks of the construction of new l...On the basis of combing domestic and foreign related literature and research practice,the influence mechanism of the construction of new liberal arts was analyzed,and the fundamental tasks of the construction of new liberal arts in Tibet were summarized.Based on 173 field questionnaires in Tibet,factor analysis was used to conduct empirical analysis.It is found that the cumulative contribution of the first,second,third and fourth common factor was 24.921%,21.742%,17.331%,and 14.206%,respectively.Professional orientation,the reform of talent training mode,teacher ability,quality and level of the teaching team,curriculum system reform,teaching content reform,education training service,and other evaluation indicators are the key points of the construction of new liberal arts.The research conclusion is that the construction of new liberal arts needs to highlight the"three positions";it is needed to plan and promote various resources to focus on the ability and level of professional teachers’social services;the managers and professional teachers should be the leaders and participants of the innovation of the talent training model respectively.Finally,relevant policy recommendations were put forward.展开更多
This paper deals with the characteristics of silicon modification with lanthanum of Al-Si eutectic alloy in sand mold and metal mold with optical microscopy,scanning electron microscopy,electron microprobe and X-ray d...This paper deals with the characteristics of silicon modification with lanthanum of Al-Si eutectic alloy in sand mold and metal mold with optical microscopy,scanning electron microscopy,electron microprobe and X-ray diffractometer.It is found that the amount of lanthanum,liquid alloy condition,holding time and stir- ring liquid influence the modification of silicon.The modification of silicon with lanthanum is of long effectiveness and has a“incubation time”.The modification can improve the ductility(δ_s)and tensile strength (σ_b)of the alloy,but their maximum values are not corresponding to the same amount of lanthanum.展开更多
Rockburst are often encountered in tunnel construction due to the complex geological conditions.To study the influence of unloading rate on rockburst,gneiss rockburst experiments were conducted under three groups of u...Rockburst are often encountered in tunnel construction due to the complex geological conditions.To study the influence of unloading rate on rockburst,gneiss rockburst experiments were conducted under three groups of unloading rates.A high-speed photography system and acoustic emission(AE)system were used to monitor the entire process of rockburst process in real-time.The results show that the intensity of gneiss rockburst decreases with decrease of unloading rate,which is manifested as the reduction of AE energy and fragments ejection velocity.The mechanisms are proposed to explain this effect:(i)The reduction of unloading rate changes the crack propagation mechanism in the process of rockburst.This makes the rockbursts change from the tensile failure mechanism at high unloading rate to the tension-shear mixed failure mechanism at low unloading rate,and more energy released in the form of shear crack propagation.Then,less strain energy is converted into kinetic energy of fragments ejection.(ii)Less plate cracking degree of gneiss has taken shape due to decrease of unloading rate,resulting in the destruction of rockburst incubation process.The enlightenments of reducing the unloading rate for the project are also described quantitatively.The rockburst magnitude is reduced from the medium magnitude at the unloading rate of 0.1 MPa/s to the slight magnitude at the unloading rate of 0.025 MPa/s,which was judged by the ejection velocity.展开更多
With the economic development and multicultural exchange of ethnic villages,more and more ethnic villages have embarked on the road of tourism to become rich,but also brought the problem of ecological pollution.Few ex...With the economic development and multicultural exchange of ethnic villages,more and more ethnic villages have embarked on the road of tourism to become rich,but also brought the problem of ecological pollution.Few existing literatures discuss how to alleviate the ecological pollution in ethnic villages from the perspective of tourists’environmentally responsible behavior.In the context of ethnic villages,from the perspective of integration and the attitude-context-behavior theory,this paper constructs an EV-ABC-TERB model with four variables,namely environmental attitude,local atmosphere,emotional experience and tourists’environmentally responsible behavior,to explore the characteristics,influencing factors and influencing mechanism of tourists’environmental responsibility behavior in ethnic villages.Taking Xijiang Hmong Village as the research case,questionnaire survey method and structural equation model method were used.The results show that environmental attitude positively affects emotional experience and tourists’environmentally responsible behavior.Local atmosphere positively influences tourists’environmentally responsible behavior.Emotional experience negatively affects tourists’environmentally responsible behavior and plays an intermediary role in the way that environmental attitudes affect tourists’environmentally responsible behavior.The influence of environmental attitude on emotional experience is negatively regulated by local atmosphere.Finally,based on the analysis conclusion,it provides new ideas and inspiration for the sustainable development of the ethnic village tourism.展开更多
Calcium salt is an important contributing factor for calcium-based biomineralization.To study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chl...Calcium salt is an important contributing factor for calcium-based biomineralization.To study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chloride (CaCl_(2)),calcium acetate ((CH_(3)COO)_(2)Ca) and calcium nitrate (Ca(NO_(3))_(2)),were used to prepare the biotreatment solution to carry out the biomineralization tests in this paper.Two series of biomineralization tests in solution and sand column,respectively,were conducted.Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed to determine the microscopic characteristics of the precipitated calcium carbonate (CaCO_(3)) crystals.The experimental results indicate that the biomineralization effect is the best for the CaCl2 case,followed by (CH_(3)COO)_(2)Ca,and worst for Ca(NO_(3))_(2) under the test conditions of this study (i.e.1 mol/L of calcium salt-urea).The mechanism for the effect of the calcium salt on the biomineralization of crude soybean urease mainly involves: (1) inhibition of urease activity,and (2) influence on the crystal size and morphology of CaCO_(3).Besides Ca^(2+) ,the anions in solution can inhibit the activity of crude soybean urease,and NO_(3)− has a stronger inhibitory effect on the urease activity compared with both CH_(3)COO^(−) and Cl^(−) .The co-inhibition of Ca^(2+) and NO_(3)− on the activity of urease is the key reason for the worst biomineralization of the Ca(NO_(3))_(2) case in this study.The difference in biomineralization between the CaCl_(2) and (CH_(3)COO)_(2) Ca cases is strongly correlated with the crystal morphology of the precipitated CaCO_(3).展开更多
The Yangtze River Economic Belt(YREB)is a pivotal contributor to China's economic growth,particularly as the nation undergoes a green transformation.Achieving synergistic reductions on pollution and carbon emissio...The Yangtze River Economic Belt(YREB)is a pivotal contributor to China's economic growth,particularly as the nation undergoes a green transformation.Achieving synergistic reductions on pollution and carbon emissions is deemed crucial for this transition.This paper examines the spatial and temporal changes in the synergy of pollution and carbon reduction in the YREB and delves into the underlying mechanisms.Our findings indicate that while the synergy in the YREB is increasing,it manifests disparities across regions,with the lower reaches outperforming the middle and upper ones.Enterprise behavior,government guidance,and regional endowments influence this synergy.Cities in the YREB must strategically plan their urban scale,curb population overgrowth,recalibrate their industrial structures,curtail energy consumption,and enhance policy efficacy.Distinct regions should prioritize various objectives:the lower reaches should hasten scientific advancements and technological innovations;the middle reaches should foster innovation and industrial upgrades;and the upper reaches should prioritize rural and urban land intensification.展开更多
This paper investigates the effect and transmission mechanism of air pollution on urbanization based on data from China’s 107 cities during 2005–2018.In order to identify the impact of air pollution on China’s urba...This paper investigates the effect and transmission mechanism of air pollution on urbanization based on data from China’s 107 cities during 2005–2018.In order to identify the impact of air pollution on China’s urbanization,we utilized night light data to represent the level of urbanization and used temperature inversion as an instrumental variable to mitigate endogeneity within the two-stage least squares framework.The results suggest that air pollution significantly slowed China’s urbanization process with economic growth acting as the transmission mechanism.The heterogeneity analyses revealed that air pollution had a greater negative impact on urbanization in northern regions than that in southern regions,and a greater negative impact in resource-oriented cities than that in non-resource-based cities.We also find that air pollution was to the detriment of urbanization in larger cities,which have more than 3 million residents,while it did not have a significant impact on Type II large cities,which have fewer than 3 million residents.展开更多
Microbial fermented feed possesses a natural fermentation flavor and exhibits good palatability.It is not only easily digestible and absorbable by livestock but also non-toxic.Additionally,it has the capacity to inhib...Microbial fermented feed possesses a natural fermentation flavor and exhibits good palatability.It is not only easily digestible and absorbable by livestock but also non-toxic.Additionally,it has the capacity to inhibit the proliferation of pathogenic bacteria,facilitate the growth and development of animals,and enhance their immune response,disease resistance,and overall production performance.This paper summarizes the selection of common feed materials and microbial strains used in fermented feed,as well as their effects on the growth performance,muscle quality,antioxidant capacity,and immune function of crayfish.The aim of this study is to provide a reference for the further popularization and application ofmicrobialfermented feed in crayfishaquaculture.展开更多
Minority characteristic villages are an important carrier of Chinese cultural heritage and key locations for the implementation of the rural revitalization strategy.This study takes 683 villages with national minority...Minority characteristic villages are an important carrier of Chinese cultural heritage and key locations for the implementation of the rural revitalization strategy.This study takes 683 villages with national minority characteristics in the upper reaches of the Yangtze River Basin as the research object.It uses spatial analysis and geographic exploration technology to explore the spatial distribution characteristics of minority characteristic villages in the upper reaches of the Yangtze River Basin,the formation mechanism,and potential for rural revitalization.The results show that:(1)The spatial distribution of ethnic minority villages in the upper reaches of the Yangtze River Basin is not balanced,with an overall distribution pattern of"dense in the south and sparse in the north".(2)The spatial distribution of ethnic villages is of the aggregation type,and the overall spatial distribution is characterized by"one nucleus with multiple points"and"cold in the north and hot in the east".(3)The main factors affecting the spatial distribution of ethnic villages are the economy,population,ecology,transportation,and natural environment.(4)The spatial diferentiation of ethnic villages in the upper reaches of the Yangtze River Basin is the result of a combination of factors.In the context of future rural revitalization,we should anchor the revitalization and protection of ethnic villages,focus on the construction of inter-regional cooperation mechanisms,refine the spatial layout and optimal integration,and sincerely devote ourselves to the excavation and inheritance of the unique culture of ethnic groups to comprehensively,profoundly,and systematically promote the efficient practice of the rural revitalization strategy.展开更多
Mountain tourism destinations provide individuals with the opportunity to articulate their feelings,enhance their inner selves,and foster personal growth.Exploring the factors and action paths of the health benefit pe...Mountain tourism destinations provide individuals with the opportunity to articulate their feelings,enhance their inner selves,and foster personal growth.Exploring the factors and action paths of the health benefit perception of mountain tourists is crucial for advancing the sustainable development of mountain tourism destinations.This study conducted a questionnaire survey among tourists in the Yulong Snow Mountain Scenic Spot,and obtained 41o valid responses.Based on the person-environment fit theory and self-regulation theory,this study used structural equation modeling and the Bootstrapping technique to explore the impact mechanism of tourist-environment fit(T-E fit),flow experience,and place attachment on mountain tourists'health benefit perception.There are three main conclusions of this study.(1)The impact of T-E fit on mountain tourists'health benefit perception is completely mediated by flow experience and place attachment.(2)Place attachment exerts an independent mediating effect between T-E fit and mountain tourists'health benefit perception.(3)T-E fit positively affects mountain tourists'health benefit perception through the chain mediating effects of flow experience and place attachment.This research enhances the empirical findings about T-E fit,expands the research perspective of mountain tourists'health benefit perception,and provides practical guidance for the management and development of mountain health tourism destinations.This study also broadens the multi-dimensional research perspective on mountain tourists'health benefit perception,reveals the chain mediating role of flow experience and place attachment,and offers practical guidance for promoting the formulation of differentiated health tourism products in mountain tourist attractions,as well as case references for establishing health tourism sites in mountainous regions.展开更多
基金a phased achievement of“Research on the Digital Transformation Mechanism and Policies of the Agricultural Industry in the Chengdu-Chongqing Economic Circle”(Ref.:24YBCY03),a project funded by the Sichuan Academy of Social Sciences。
文摘Based on micro-survey data from 894 farmers in Sichuan Province,this study employs the Ordinary Least Squares(OLS),Two-Stage Least Squares(2SLS),mediating effect,and moderating effect models to comprehensively analyze the mechanisms and effects of digital literacy in empowering farmers’common prosperity.Endogeneity and robustness are addressed using the Sobel test,the Bootstrap,and moderating effect plots.The findings indicate that first,after controlling for variables such as age,gender,and planting years,digital literacy significantly and positively influences the common prosperity of farmers at the 5%level;second,enhanced digital literacy promotes higher levels of technology adoption and information accumulation among farmers,thereby increasing the probability of achieving common prosperity.The mediating effects of technology adoption and information sharing account for 21.10%and 33.94%of the total effect,respectively;and third,the information environment and financial empowerment play positive moderation roles in the effect of digital literacy on farmers’common prosperity,with the moderation effects significant at the 1%and 10%levels,respectively.Therefore,we recommend policies that enhance the access of farmers to digital literacy training,strengthen rural digital infrastructure,establish integrated rural information-sharing platforms,and create an enabling environment for the adoption of digital technologies.
文摘With the rapid development of China’s economy,the coordinated development of resident income and GDP has become an important indicator to measure local economic development.How to realize the synergistic growth of the two in the new era is of great significance for promoting the sustainable development of the local economy.Based on the theory of the coordinated development of resident income and GDP,this paper will take Shandong Province as an example to analyze the interaction between resident income growth and GDP,find out the influencing factors that restrict the coordinated development of resident income and GDP,and explore the impact of the coordinated development of resident income and GDP on local economic development.Finally,relevant policies will be studied.How to effectively increase residents’income,promote the sustainable and healthy development of the local economy,and put forward relevant suggestions to promote the coordinated development of residents’income and GDP.
文摘The author’s combined numerical model consisting of a third generation shallow water wave model and a 3 D tide surge model with wave dependent surface wind stress were used to study the influence of waves on tide surge motion. For the typical weather case, in this study, the magnitude and mechanism of the influence of waves on tide surges in the Bohai Sea were revealed for the first time. The results showed that although consideration of the wave dependent surface wind stresses raise slightly the traditional surface wind stress, due to the accumulated effects, the computed results are improved on the whole. Storm level maximum modulation can reach 0.4 m. The results computed by the combined model agreed well with the measured data.
基金supported by the National Natural Science Foundation of China(22179089)。
文摘Throughout versatile metal compositions and unique structural characteristics,polynary metal atom catalysts(PACs)readily harness synergistic intermetallic effects,significantly boosting the catalytic performances.These catalysts are featured by favorable catalytic activity,stability and selectivity,offering avenues to tackle challenges in energy conversion,environmental protection and chemical synthesis.Nevertheless,an in-depth understanding and comprehensive summary of the structure-performance relationship for the emerging PACs remains elusive.This review embarks from the classification of PACs,delving further into the origins of catalytic activity and mechanisms underpinning performance enhancement.At the beginning,it outlines the fundamental concepts,preparation methods and accurate recognition of PACs.Subsequently,it centers on discussing the origins of activity,strategies for performance optimization,mechanisms of action,and application scenarios across diverse catalytic reactions.Moreover,the unexplored issues and future perspectives of PACs are proposed at the end,stating their pivotal roles in advancing green chemistry and the sustainable energy realm.This review overall aims to provide valuable insight and guidance for the preparation and application of PACs.
基金financial support from the National Natural Science Foundation of China(No.51904324,51974348,U19B6003)
文摘In recent years,supercritical CO_(2)flooding has become an effective method for developing lowpermeability reservoirs.In supercritical CO_(2)flooding different factors influence the mechanism of its displacement process for oil recovery.Asynchronous injection-production modes can use supercritical CO_(2)to enhance oil recovery but may also worsen the injection capacity.Cores with high permeability have higher oil recovery rates and better injection capacity,however,gas channeling occurs.Supercritical CO_(2)flooding has a higher oil recovery at high pressure levels,which delays the occurrence of gas channeling.Conversely,gas injection has lower displacement efficiency but better injection capacity at the high water cut stage.This study analyzes the displacement characteristics of supercritical CO_(2)flooding with a series of experiments under different injection and production parameters.Experimental results show that the gas breakthrough stage has the fastest oil production and the supercritical CO_(2)injection capacity variation tendency is closely related to the gas-oil ratio.Further experiments show that higher injection rates represent significant ultimate oil recovery and injection index,providing a good reference for developing low-permeability reservoirs.
基金supported by the grants from the Outstanding Academic Leaders Plan of Shanghai [Grant No.2018BR07]the National Science Foundation of China [Grant No.81572061]+1 种基金Program for Young Medical Technicians(Clinical Examination)in Shanghai [2016]05Shanghai Health and Family Planning Commission Clinical Research Project for Health Industry [Grant No.20184Y0199]
文摘The development of cancer is a complex process that requires the participation of many factors,including mutations in genes, regulation of signaling pathways, disruption of homeostasis, and failure of self-monitoring mechanisms. Sufficient evidence has
基金the State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology(No.SKLCRSM22KF011)the National Natural Science Foundation of China(Nos.52130411,52104191,51974120,and 51904103)+1 种基金the Natural Science Foundation of Hunan Province(No.2021JJ40204)the Science and Technology Innovation Program of Hunan Province(No.2020RC3047).
文摘The study of pressure stimulated current(PSC)changes of rocks is significant to monitor dynamic disasters in mines and rock masses.The existing studies focus on change laws and mechanism of currents generated under the loading of rocks.An electrical and mechanics test system was established in this paper to explore the impacts of loading rates on PSCs.The results indicated that PSC curves of different rocks had different change laws under low/high loading rates.When the loading rate was relatively low,PSC curves firstly changed gently and then increased exponentially.Under high loading rates,PSC curves experienced the rapid increase stage,gentle increase stage and sudden change stage.The compressive strength could greatly affect the peak PSC in case of rock failure.The loading rate was a key factor in average PSC.Under low loading rates,the variations of PSCs conformed to the damage charge model of fracture mechanics,while they did not at the fracture moment.Under high loading rates,the PSCs at low stress didn’t fit the model due to the stress impact effects.The experimental results could provide theoretical basis for the influence of loading rates on PSCs.
基金Supported by Special Item of Public Welfare Industry (Meteorology)Science Research (GYHY201106006)Special Item of Forecaster of China Meteorological Administration (CMATG2007Y08)Key Topics of Shandong Meteorological Bureau (2010sdqxz10)
文摘[Objective] The research aimed to study the possible mechanism of terrain effect on cold-flow snowstorm.[Method] By using the meso-scale numerical model(WRF),a cold-flow snowstorm weather process in Shandong Peninsula was carried out numerical simulation and terrain sensitivity contrast test.The possible reason of terrain effect on falling zone and strength of snowstorm was deeply analyzed from water vapor,thermodynamic field and so on.[Result] The mountain terrain in Shandong Peninsula had great influences on falling zone and strength of cold-flow snowstorm.The strength of snowstorm obviously increased,and the snowfall center obviously moved northward.The main reason was that terrain caused the low-level wind field convergence and vertical movement in the troposphere strengthened.Then,the spatial distribution of water vapor and snow water content in the cold-flow snowstorm process obviously changed.So,the whole snowstorm process was affected.[Conclusion] The mountain terrain in Shandong Peninsula was the important element which needed to be focused on considering in the forecast analysis of cold-flow snowstorm weather process.
基金Supported by the Youth Science Foundation of Shanxi Province under Grant No 2013021010-3the National Natural Science Foundation of China under Grant Nos 61434002 and 11404202
文摘Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and orientations of the stress can be classified into three types. The corresponding physical conditions for each type of the loop are deduced based on the principle of minimal energy. The equation of the critical stress is derived, which can judge whether the loops show hysteresis or not. Numerical calculations suggest that except for the magnitude of the mechanical stress, the relative orientation of the stress is also an important factor to tune the exchange bias effect.
文摘In this paper, the relation between Asian summer monsoon circulation and sea surface temperature anomalies over equatorial central-eastern Pacific is investigated by using a global spectral model. This model has nine layers in the vertical and the model variables are represented in the horizontal as truncated expansions of the surface spherical harmonics with rhomboidal truncation at wave number 15. The model involves comparatively complete physical processes and parameterizations with mountains.Using the above model, two experimental schemes are designed, namely control case and anomalous sea surface temperature case. The above two schemes are respectively integrated for forty days and the simulated results are obtained from the last 30-day averaged simulations.The simulations show that positive SST anomalies over equatorial central-eastern Pacific weakens Indian monsoon circulation,decreases precipitation in Indian sub-continent whereas it intensifies East Asian monsoon circulation and increases precipitation in East Asian area. All these results reflect the characteristics of Asian summer monsoon during the El Nino period. In this paper, SST anomalies over equatorial central-eastern Pacific have a direct influence on the intensity and position of subtropical high via the wave train over Northern Hemisphere, which is similar to that suggested by Nitta(1987) and the wave train over Southern Hemisphere has an influence on the intensity of Muscarene high and Australia high resulting in affecting cross equatorial flow. As a result, atmospheric interior heat sources and sinks are redistributed because of the change of cross equatorial flow. And the response of atmosphere to the new heat source and sink has a significant influence on Asian summer monsoon.
基金Supported by Teaching and Research Project of Tibet Autonomous Region Education Department(XZJYKTJX18,XZJKY19417)Quality Engineering Project(5333219008)。
文摘On the basis of combing domestic and foreign related literature and research practice,the influence mechanism of the construction of new liberal arts was analyzed,and the fundamental tasks of the construction of new liberal arts in Tibet were summarized.Based on 173 field questionnaires in Tibet,factor analysis was used to conduct empirical analysis.It is found that the cumulative contribution of the first,second,third and fourth common factor was 24.921%,21.742%,17.331%,and 14.206%,respectively.Professional orientation,the reform of talent training mode,teacher ability,quality and level of the teaching team,curriculum system reform,teaching content reform,education training service,and other evaluation indicators are the key points of the construction of new liberal arts.The research conclusion is that the construction of new liberal arts needs to highlight the"three positions";it is needed to plan and promote various resources to focus on the ability and level of professional teachers’social services;the managers and professional teachers should be the leaders and participants of the innovation of the talent training model respectively.Finally,relevant policy recommendations were put forward.
文摘This paper deals with the characteristics of silicon modification with lanthanum of Al-Si eutectic alloy in sand mold and metal mold with optical microscopy,scanning electron microscopy,electron microprobe and X-ray diffractometer.It is found that the amount of lanthanum,liquid alloy condition,holding time and stir- ring liquid influence the modification of silicon.The modification of silicon with lanthanum is of long effectiveness and has a“incubation time”.The modification can improve the ductility(δ_s)and tensile strength (σ_b)of the alloy,but their maximum values are not corresponding to the same amount of lanthanum.
基金The financial support from the National Natural Science Foundation of China(Grant Nos.41941018 and 52074299)the Fundamental Research Funds for the Central Universities of China(Grant No.2023JCCXSB02)。
文摘Rockburst are often encountered in tunnel construction due to the complex geological conditions.To study the influence of unloading rate on rockburst,gneiss rockburst experiments were conducted under three groups of unloading rates.A high-speed photography system and acoustic emission(AE)system were used to monitor the entire process of rockburst process in real-time.The results show that the intensity of gneiss rockburst decreases with decrease of unloading rate,which is manifested as the reduction of AE energy and fragments ejection velocity.The mechanisms are proposed to explain this effect:(i)The reduction of unloading rate changes the crack propagation mechanism in the process of rockburst.This makes the rockbursts change from the tensile failure mechanism at high unloading rate to the tension-shear mixed failure mechanism at low unloading rate,and more energy released in the form of shear crack propagation.Then,less strain energy is converted into kinetic energy of fragments ejection.(ii)Less plate cracking degree of gneiss has taken shape due to decrease of unloading rate,resulting in the destruction of rockburst incubation process.The enlightenments of reducing the unloading rate for the project are also described quantitatively.The rockburst magnitude is reduced from the medium magnitude at the unloading rate of 0.1 MPa/s to the slight magnitude at the unloading rate of 0.025 MPa/s,which was judged by the ejection velocity.
文摘With the economic development and multicultural exchange of ethnic villages,more and more ethnic villages have embarked on the road of tourism to become rich,but also brought the problem of ecological pollution.Few existing literatures discuss how to alleviate the ecological pollution in ethnic villages from the perspective of tourists’environmentally responsible behavior.In the context of ethnic villages,from the perspective of integration and the attitude-context-behavior theory,this paper constructs an EV-ABC-TERB model with four variables,namely environmental attitude,local atmosphere,emotional experience and tourists’environmentally responsible behavior,to explore the characteristics,influencing factors and influencing mechanism of tourists’environmental responsibility behavior in ethnic villages.Taking Xijiang Hmong Village as the research case,questionnaire survey method and structural equation model method were used.The results show that environmental attitude positively affects emotional experience and tourists’environmentally responsible behavior.Local atmosphere positively influences tourists’environmentally responsible behavior.Emotional experience negatively affects tourists’environmentally responsible behavior and plays an intermediary role in the way that environmental attitudes affect tourists’environmentally responsible behavior.The influence of environmental attitude on emotional experience is negatively regulated by local atmosphere.Finally,based on the analysis conclusion,it provides new ideas and inspiration for the sustainable development of the ethnic village tourism.
基金the financial support by the National Natural Science Foundation of China(NSFC)(Grant Nos.52178319 and 52108307)the Natural Science Foundation of Fujian Province,China(Grant No.2022J05127).
文摘Calcium salt is an important contributing factor for calcium-based biomineralization.To study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chloride (CaCl_(2)),calcium acetate ((CH_(3)COO)_(2)Ca) and calcium nitrate (Ca(NO_(3))_(2)),were used to prepare the biotreatment solution to carry out the biomineralization tests in this paper.Two series of biomineralization tests in solution and sand column,respectively,were conducted.Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed to determine the microscopic characteristics of the precipitated calcium carbonate (CaCO_(3)) crystals.The experimental results indicate that the biomineralization effect is the best for the CaCl2 case,followed by (CH_(3)COO)_(2)Ca,and worst for Ca(NO_(3))_(2) under the test conditions of this study (i.e.1 mol/L of calcium salt-urea).The mechanism for the effect of the calcium salt on the biomineralization of crude soybean urease mainly involves: (1) inhibition of urease activity,and (2) influence on the crystal size and morphology of CaCO_(3).Besides Ca^(2+) ,the anions in solution can inhibit the activity of crude soybean urease,and NO_(3)− has a stronger inhibitory effect on the urease activity compared with both CH_(3)COO^(−) and Cl^(−) .The co-inhibition of Ca^(2+) and NO_(3)− on the activity of urease is the key reason for the worst biomineralization of the Ca(NO_(3))_(2) case in this study.The difference in biomineralization between the CaCl_(2) and (CH_(3)COO)_(2) Ca cases is strongly correlated with the crystal morphology of the precipitated CaCO_(3).
基金National Natural Science Foundation of China,No.42371318。
文摘The Yangtze River Economic Belt(YREB)is a pivotal contributor to China's economic growth,particularly as the nation undergoes a green transformation.Achieving synergistic reductions on pollution and carbon emissions is deemed crucial for this transition.This paper examines the spatial and temporal changes in the synergy of pollution and carbon reduction in the YREB and delves into the underlying mechanisms.Our findings indicate that while the synergy in the YREB is increasing,it manifests disparities across regions,with the lower reaches outperforming the middle and upper ones.Enterprise behavior,government guidance,and regional endowments influence this synergy.Cities in the YREB must strategically plan their urban scale,curb population overgrowth,recalibrate their industrial structures,curtail energy consumption,and enhance policy efficacy.Distinct regions should prioritize various objectives:the lower reaches should hasten scientific advancements and technological innovations;the middle reaches should foster innovation and industrial upgrades;and the upper reaches should prioritize rural and urban land intensification.
基金supported by Preliminary Funding Project of Hubei Provincial Department of Education[Grant No.22ZD100].
文摘This paper investigates the effect and transmission mechanism of air pollution on urbanization based on data from China’s 107 cities during 2005–2018.In order to identify the impact of air pollution on China’s urbanization,we utilized night light data to represent the level of urbanization and used temperature inversion as an instrumental variable to mitigate endogeneity within the two-stage least squares framework.The results suggest that air pollution significantly slowed China’s urbanization process with economic growth acting as the transmission mechanism.The heterogeneity analyses revealed that air pollution had a greater negative impact on urbanization in northern regions than that in southern regions,and a greater negative impact in resource-oriented cities than that in non-resource-based cities.We also find that air pollution was to the detriment of urbanization in larger cities,which have more than 3 million residents,while it did not have a significant impact on Type II large cities,which have fewer than 3 million residents.
文摘Microbial fermented feed possesses a natural fermentation flavor and exhibits good palatability.It is not only easily digestible and absorbable by livestock but also non-toxic.Additionally,it has the capacity to inhibit the proliferation of pathogenic bacteria,facilitate the growth and development of animals,and enhance their immune response,disease resistance,and overall production performance.This paper summarizes the selection of common feed materials and microbial strains used in fermented feed,as well as their effects on the growth performance,muscle quality,antioxidant capacity,and immune function of crayfish.The aim of this study is to provide a reference for the further popularization and application ofmicrobialfermented feed in crayfishaquaculture.
基金The National Natural Science Foundation of China(42271228,41871176,42361028)The Guizhou Science and Technology Foundation(ZK[2021]General 186)+1 种基金The Natural Science Research Fund of Guizhou Provincial Department of Education(Guizhou Jiaohe KY Zi[2022]No.156)The Guizhou Normal University Doctoral Research Project(GZNUD[2019]No.5)。
文摘Minority characteristic villages are an important carrier of Chinese cultural heritage and key locations for the implementation of the rural revitalization strategy.This study takes 683 villages with national minority characteristics in the upper reaches of the Yangtze River Basin as the research object.It uses spatial analysis and geographic exploration technology to explore the spatial distribution characteristics of minority characteristic villages in the upper reaches of the Yangtze River Basin,the formation mechanism,and potential for rural revitalization.The results show that:(1)The spatial distribution of ethnic minority villages in the upper reaches of the Yangtze River Basin is not balanced,with an overall distribution pattern of"dense in the south and sparse in the north".(2)The spatial distribution of ethnic villages is of the aggregation type,and the overall spatial distribution is characterized by"one nucleus with multiple points"and"cold in the north and hot in the east".(3)The main factors affecting the spatial distribution of ethnic villages are the economy,population,ecology,transportation,and natural environment.(4)The spatial diferentiation of ethnic villages in the upper reaches of the Yangtze River Basin is the result of a combination of factors.In the context of future rural revitalization,we should anchor the revitalization and protection of ethnic villages,focus on the construction of inter-regional cooperation mechanisms,refine the spatial layout and optimal integration,and sincerely devote ourselves to the excavation and inheritance of the unique culture of ethnic groups to comprehensively,profoundly,and systematically promote the efficient practice of the rural revitalization strategy.
基金The National Natural Science Foundation of China(41961021)The Philosophy and Social Sciences Innovation Team of Yunnan Province(2020CX09)。
文摘Mountain tourism destinations provide individuals with the opportunity to articulate their feelings,enhance their inner selves,and foster personal growth.Exploring the factors and action paths of the health benefit perception of mountain tourists is crucial for advancing the sustainable development of mountain tourism destinations.This study conducted a questionnaire survey among tourists in the Yulong Snow Mountain Scenic Spot,and obtained 41o valid responses.Based on the person-environment fit theory and self-regulation theory,this study used structural equation modeling and the Bootstrapping technique to explore the impact mechanism of tourist-environment fit(T-E fit),flow experience,and place attachment on mountain tourists'health benefit perception.There are three main conclusions of this study.(1)The impact of T-E fit on mountain tourists'health benefit perception is completely mediated by flow experience and place attachment.(2)Place attachment exerts an independent mediating effect between T-E fit and mountain tourists'health benefit perception.(3)T-E fit positively affects mountain tourists'health benefit perception through the chain mediating effects of flow experience and place attachment.This research enhances the empirical findings about T-E fit,expands the research perspective of mountain tourists'health benefit perception,and provides practical guidance for the management and development of mountain health tourism destinations.This study also broadens the multi-dimensional research perspective on mountain tourists'health benefit perception,reveals the chain mediating role of flow experience and place attachment,and offers practical guidance for promoting the formulation of differentiated health tourism products in mountain tourist attractions,as well as case references for establishing health tourism sites in mountainous regions.
