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
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
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
[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
Yu‑Jun Xia1,2,ZhuoraThe automotive industry’s trend towards lightweighting has led to a widespread usage of high-strength steels(HSS),which poses challenges for resistance spot welding(RSW)process in auto body manufa...Yu‑Jun Xia1,2,ZhuoraThe automotive industry’s trend towards lightweighting has led to a widespread usage of high-strength steels(HSS),which poses challenges for resistance spot welding(RSW)process in auto body manufacturing.One such challenge is the frequent occurrence of the initial gap(IG),which can negatively impact the consistency of the RSW process for HSS.This study aims to reveal this impact by comparing multi-sensor process signals,weld surface morphology,nugget size,and its growth process under standard and two-sided IG conditions.A comprehensive analysis of energy input and contact status is performed to investigate the influence mechanism of IG condition on nugget growth and process signal evolution.The study found that the IG disturbance reduces the initial contact area of the sheet-to-sheet interface in comparison to the standard condition.This results in a faster rise in the sheet temperature,an earlier peak in the resistance signal,and a greater susceptibility to expulsion at the early stage of the welding process.During the subsequent process,there is a significant increase in the contact area of both sheet-to-sheet and electrode-to-sheet interfaces,leading to a decrease in dynamic resistance signal and heat generation.Consequently,the nugget size and electrode displacement signal are smaller than the standard ones.Furthermore,the larger contact area along the gap constraint direction causes more heat generation,ultimately resulting in a larger nugget dimension and indentation size in this particular direction.This research can provide guidance for online monitoring and control for the RSW process of HSS.展开更多
Urbanization significantly affects the balance of key elements such as water,heat,and carbon in cities.However,previous studies have not integrated these factors for comprehensive analysis.Here,we proposed a waterheat...Urbanization significantly affects the balance of key elements such as water,heat,and carbon in cities.However,previous studies have not integrated these factors for comprehensive analysis.Here,we proposed a waterheat-carbon(WHC)nexus model to provide a holistic understanding of urbanization's impacts.Furthermore,we employed the model to identify the mechanisms and response thresholds of urbanization through this coupling approach.Our findings reveal three key insights:(1)WHC exhibits a nonlinear,inverted S-shaped response to urbanization.(2)The mechanisms through which urbanization impacts WHC differ significantly across urbanization gradients.Acrossing urbanization gradients,the complexity of impact pathways increases,with direct effects becoming more pronounced and positive impact pathways emerging progressively.(3)We identified priority zones for restoration and protection based on the likelihood of units shifting between lower-risk and higher-risk categories.Our study enhances understanding of the WHC-urbanization nexus and highlights the importance of accounting for threshold effects and environmental interactions when examining the impact between urbanization and WHC.This framework can be adapted to other urban areas experiencing similar challenges.展开更多
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
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
In the context of rapid urbanization and industrialization,achieving a coordinated relationship between urban construction land expansion(UCLE)and economic growth is essential for sustainable development,especially in...In the context of rapid urbanization and industrialization,achieving a coordinated relationship between urban construction land expansion(UCLE)and economic growth is essential for sustainable development,especially in developing countries.This study examined the spatiotemporal relationship between UCLE and economic growth in the Yellow River Basin(YRB),China from 2000 to 2020.An extended IPAT(Impact=Population×Affluence×Technology)decoupling framework and the geographical detector model were employed at a 5-km grid scale.Results show that urban construction land(UCL)expanded slowly before 2005,accelerated between 2005 and 2015,and declined thereafter.Since 2015,UCLE in most parts of the YRB has gradually decoupled from economic growth.The geographical detector analysis revealed that economic growth,along with its interactions with natural,locational,and socioeconomic factors,significantly influenced UCLE.Notably,location factors have gained importance since 2015,reducing the role of economic growth as the primary driver of UCLE in the YRB’s lower reaches.Nonetheless,economic growth continues to significantly influence the upper and middle reaches.These findings highlight the need for more precise and differentiated strategies for land utilization and economic growth,tailored to finer spatial scales,to better integrate human-land systems and promote high-quality regional development.展开更多
To investigate the influence of coarse aggregate parent rock properties on the elastic modulus of concrete,the mineralogical properties and stress-strain curves of granite and dolomite parent rocks,as well as the stre...To investigate the influence of coarse aggregate parent rock properties on the elastic modulus of concrete,the mineralogical properties and stress-strain curves of granite and dolomite parent rocks,as well as the strength and elastic modulus of mortar and concrete prepared with mechanism aggregates of the corresponding lithology,and the stress-strain curves of concrete were investigated.In this paper,a coarse aggregate and mortar matrix bonding assumption is proposed,and a prediction model for the elastic modulus of mortar is established by considering the lithology of the mechanism sand and the slurry components.An equivalent coarse aggregate elastic modulus model was established by considering factors such as coarse aggregate particle size,volume fraction,and mortar thickness between coarse aggregates.Based on the elastic modulus of the equivalent coarse aggregate and the remaining mortar,a prediction model for the elastic modulus of the two and three components of concrete in series and then in parallel was established,and the predicted values differed from the measured values within 10%.It is proposed that the coarse aggregate elastic modulus in highstrength concrete is the most critical factor affecting the elastic modulus of concrete,and as the coarse aggregate elastic modulus increases by 27.7%,the concrete elastic modulus increases by 19.5%.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 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
The effective use of land in Northeast China is of great significance for ensuring national food security and regional rural revitalization.In this study,based on the survey data collected from Jilin Province,Northeas...The effective use of land in Northeast China is of great significance for ensuring national food security and regional rural revitalization.In this study,based on the survey data collected from Jilin Province,Northeast China,we analyzed the vacancy rates of rural homesteads in suburban,outer suburban,and remote villages,as well as the withdrawal intention of rural-settled farmers,urbansettled farmers,and farmers with urban and rural dual residency from vacant homesteads.From the perspective of farmers’perceptions,this study constructed a theoretical framework of the influence mechanism of their withdrawal intention and analyzed such mechanism by constructing a structural equation model.The results indicated that:1)rural homestead vacancy rates increased with distance from the village to the city.2)rural-settled farmers showed a low withdrawal intention for vacant rural homesteads,followed by urban and rural dual-residence farmers,and urban-settled farmers showed the highest withdrawal intention.3)the relative importance of the factors influencing withdrawal intention is in the following order:policy awareness>interest perception>living environment perception>family characteristics.Finally,this study discussed the reformation of the homestead system and rural homestead transition in Northeast China,which can provide policy support to increase the potential of cultivated land and promote sustainable rural development and urban-rural coordination.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
Land use issue is an important constraining force to limit economic sustainable development of China. Urban and rural rapid expansion depletes valued land resources under the background of rapid urbanization. An exten...Land use issue is an important constraining force to limit economic sustainable development of China. Urban and rural rapid expansion depletes valued land resources under the background of rapid urbanization. An extensive use pattern might cause a serious waste of land resources. The study on influencing mechanism of land intensive use （LIU） in China at the county level is a key tool for effective LIU practice and policy-making. This paper uses OLS model, Spatial Panel Lagged model and Spatial Panel Error model to quantitatively analyze the influencing mechanisms of five class factors and 17 variables supported by GIS （Geographic Information System） and MATLAB. And a comprehensive data set was devel- oped including physical geography and socio-economic information of 2286 counties. Meanwhile, the spatiotemporal pattern of LIU has discussed by means of GIS. The results show that Spatial Panel Data models are slightly superior to OLS model in terms of signifi- cance and confidence level. Regression results of these models indicate that industrialization, urbanization, economic development level, location, transportation and policy have significant impact on LIU of counties. The variables of physical geography are less significant than socio-economic variables. An ignored variable of historical factor, however, became the best significant factor. In the future, the LIU at the county level should take advantage of the new situation by enhancing favorable factors and reducing disadvantageous ones, which can be acquired by improving the entire level and quality of industrialization and urbanization. We argued that an efficient and complete land market and operating system should be built to reflect market-oriented activities at the first place, then, differential LIU regulation policies and measurements should be optimized according to regional differences. In the meantime, we should pay close attention to the carrying capacity of local resources and environments when conducting LIU practices.展开更多
Spatial equality of access to basic public services, especially medical care services which are directly related to life safety, is the first step to achieve the goal of equalization of basic public services for all t...Spatial equality of access to basic public services, especially medical care services which are directly related to life safety, is the first step to achieve the goal of equalization of basic public services for all the people proposed by central government of China. Using the spatial analysis and the statistical analysis, this study evaluates the spatial differentiation of medical care facilities accessibility by constructing STT(Shortest Travel-Time) and SAI(Spatial Accessibility Index). And then this study explores the neighborhood effects on the medical care facilities accessibility in Beijing, with a particular focus on the effect of neighborhood migrant proportion by constructing spatial dependent regression model. The spatial accessibility analysis of medical care facilities show that the spatial distribution of medical care facilities was basically consistent with administrative regions but not with population demands. Bivariate LISA cluster maps identify that suburban areas are the overlapped clusters of high percent of migrants and limited medical care services. This is associated with the public service allocation rule in China, which stresses equality within urban areas and within rural areas but overlooks equality between urban areas and rural areas; and stresses local resident demands but overlooks migrant demands. To estimate the effects on medical care accessibility of neighborhood migrant proportion, spatial dependence models are applied due to spatial dependence of accessibility of medical care facilities. The regression results show that neighborhoods with high percent of migrants, even conditioning on neighborhood SES, are related to limited spatial accessibility of medical care services. Besides neighborhood characteristics, another important factor influencing spatial accessibility of medical care services is the process of spatial spillover effects. This indicates that the attenuate accessibility of medical care services for migrants is not only because of their own constraints but also because of their proximity to other disadvantaged neighborhoods. Therefore, it is urgently needed to increase the medical facilities in the suburban areas, to take into account migrants' demands and to reduce residential segregation between local residents and migrants for local governments to achieve the goal of equalization of medical care service.展开更多
Following climate change,changes in precipitation patterns and food security are major challenges faced by humans.However,research on how these changes in precipitation pattern impacts food supply is limited.This stud...Following climate change,changes in precipitation patterns and food security are major challenges faced by humans.However,research on how these changes in precipitation pattern impacts food supply is limited.This study aims to elucidate this impact and response mechanisms using precipitation data of a climate change-sensitive confluence zone of the southwest and southeast monsoons in Yunnan Province from 1988 to 2018.The results revealed that the precipitation pattern could be divided into three periods:abundant precipitation(Stage I,from 1988 to 2004),decreased precipitation(Stage II,from 2005 to 2015),and drought recovery(Stage III,from 2016 to 2018).Following the transition from Stage I to Stage II and from Stage II to Stage III,the area of precipitation changed significantly,accounting for 15.07%,13.87%,and 16.53%of Yunnan’s total area,for Stages I,II,and III,respectively.At the provincial level,a significant positive correlation was observed between precipitation and food production(r=0.535,P<0.01),and the correlation coefficient between precipitation and grain yield was higher than that between precipitation and meat and milk production.Based on a precipitation–grain yield transect and breakpoint detection method,key precipitation thresholds affecting grain yield were estimated as 700 and 1500 mm,respectively;when precipitation was<700,700–1500,and≥1500 mm,the correlation coefficients between precipitation and grain yield were 0.448(P<0.01),0.370(P<0.01),and–0.229(P>0.05),respectively.Based on the precipitation thresholds,Yunnan Province can be divided into precipitation surplus,precipitation equilibrium,and precipitation deficit regions,corresponding countermeasures to stabilize grain yield were proposed for each of these regions.The threshold effect of precipitation on grain yield is controlled by molecular-level water–crop mechanisms,in which reactive oxygen species,a by-product of plant aerobic metabolism,plays a key regulatory role.展开更多
The Qaidam Basin(QB)is a concentrated distribution area and chemical industrial bases of salt lakes in China.Lakes in the QB have been expanding during the past 20 years.Rapid lake expansion resulted in some considera...The Qaidam Basin(QB)is a concentrated distribution area and chemical industrial bases of salt lakes in China.Lakes in the QB have been expanding during the past 20 years.Rapid lake expansion resulted in some considerable scientific issues on the protection of salt lake resources and infrastructure,and monitoring of hydrological processes at the lake-basin scale.Although the spatial-temporal trends of lake changes on the Qinghai-Tibet Plateau(QTP)have been well documented,the underlying influencing mechanism and hydrogeological implications of rapid lake changes in the QB are not well understood.Three lakes in the northern QB were selected to investigate lake water level fluctuations on different time scales based on extensive in-situ monitoring and satellite observations.The influencing mechanism and hydrogeological implications of rapid changes of terminal lakes were discussed in combination with the reported increasing precipitation rate and mass balance of glaciers in the northern QTP.Results reveal the following:(1)the fluctuation pattern of Sugan Lake was asynchronous and out of phase with that of Xiao Qaidam and Toson lakes during the monitoring period;(2)Sugan Lake water rose gradually,and the rise interval was from late April to early July.In contrast,Xiao Qaidam and Toson lakes took on a rapid and steep rise,and the rise intervalwas from late July to September;(3)the influencing mechanisms for rapid lake fluctuations are controlled by different factors:glacier and snow melting with increasing temperature for Sugan Lake and increasing precipitation for Xiao Qaidam and Toson lakes;(4)in accordance with different intervals and influencing mechanisms of rapid lake expansions in the QB,hydrological risk precaution of lakes and corresponding river catchments was conducted in different parts of the basin.This study provided an important scientific basis for assessing the hydrological process and hydrological risk precaution,and protection of salt lake resources along with rapid lake expansions in the arid area.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
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.
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National Natural Science Foundation of China(Grant Nos.52205396,52025058)National Defense Basic Scientific Research Program of China(Grant No.JCKY2021203B074)+1 种基金Young Elite Scientists Sponsorship Program by CAST(Grant No.2022QNRC001)Shanghai Rising-Star Program(Grant No.23QB1405700).
文摘Yu‑Jun Xia1,2,ZhuoraThe automotive industry’s trend towards lightweighting has led to a widespread usage of high-strength steels(HSS),which poses challenges for resistance spot welding(RSW)process in auto body manufacturing.One such challenge is the frequent occurrence of the initial gap(IG),which can negatively impact the consistency of the RSW process for HSS.This study aims to reveal this impact by comparing multi-sensor process signals,weld surface morphology,nugget size,and its growth process under standard and two-sided IG conditions.A comprehensive analysis of energy input and contact status is performed to investigate the influence mechanism of IG condition on nugget growth and process signal evolution.The study found that the IG disturbance reduces the initial contact area of the sheet-to-sheet interface in comparison to the standard condition.This results in a faster rise in the sheet temperature,an earlier peak in the resistance signal,and a greater susceptibility to expulsion at the early stage of the welding process.During the subsequent process,there is a significant increase in the contact area of both sheet-to-sheet and electrode-to-sheet interfaces,leading to a decrease in dynamic resistance signal and heat generation.Consequently,the nugget size and electrode displacement signal are smaller than the standard ones.Furthermore,the larger contact area along the gap constraint direction causes more heat generation,ultimately resulting in a larger nugget dimension and indentation size in this particular direction.This research can provide guidance for online monitoring and control for the RSW process of HSS.
基金funded by the National Forestry and Grassland Administration(Grant No.2023132050)National Forestry and Grassland Administration(Grant No.2019132703)+1 种基金National Science Foundation of China(Grants No.42171093,42101250)Fengyun 3 Satellite Ground Application Project(Grants No.FY-2(03)-AS-12.09-ZT,FY-APP-2021.0407)。
文摘Urbanization significantly affects the balance of key elements such as water,heat,and carbon in cities.However,previous studies have not integrated these factors for comprehensive analysis.Here,we proposed a waterheat-carbon(WHC)nexus model to provide a holistic understanding of urbanization's impacts.Furthermore,we employed the model to identify the mechanisms and response thresholds of urbanization through this coupling approach.Our findings reveal three key insights:(1)WHC exhibits a nonlinear,inverted S-shaped response to urbanization.(2)The mechanisms through which urbanization impacts WHC differ significantly across urbanization gradients.Acrossing urbanization gradients,the complexity of impact pathways increases,with direct effects becoming more pronounced and positive impact pathways emerging progressively.(3)We identified priority zones for restoration and protection based on the likelihood of units shifting between lower-risk and higher-risk categories.Our study enhances understanding of the WHC-urbanization nexus and highlights the importance of accounting for threshold effects and environmental interactions when examining the impact between urbanization and WHC.This framework can be adapted to other urban areas experiencing similar challenges.
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.
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Under the auspices of National Natural Science Foundation of China(No.42293271,42471222)。
文摘In the context of rapid urbanization and industrialization,achieving a coordinated relationship between urban construction land expansion(UCLE)and economic growth is essential for sustainable development,especially in developing countries.This study examined the spatiotemporal relationship between UCLE and economic growth in the Yellow River Basin(YRB),China from 2000 to 2020.An extended IPAT(Impact=Population×Affluence×Technology)decoupling framework and the geographical detector model were employed at a 5-km grid scale.Results show that urban construction land(UCL)expanded slowly before 2005,accelerated between 2005 and 2015,and declined thereafter.Since 2015,UCLE in most parts of the YRB has gradually decoupled from economic growth.The geographical detector analysis revealed that economic growth,along with its interactions with natural,locational,and socioeconomic factors,significantly influenced UCLE.Notably,location factors have gained importance since 2015,reducing the role of economic growth as the primary driver of UCLE in the YRB’s lower reaches.Nonetheless,economic growth continues to significantly influence the upper and middle reaches.These findings highlight the need for more precise and differentiated strategies for land utilization and economic growth,tailored to finer spatial scales,to better integrate human-land systems and promote high-quality regional development.
基金Funded by State Railway Administration Research Project(No.2023JS007)National Natural Science Foundation of China(No.52438002)+1 种基金Research and Development Programs for Science and Technology of China Railways Corporation(No.J2023G003)New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘To investigate the influence of coarse aggregate parent rock properties on the elastic modulus of concrete,the mineralogical properties and stress-strain curves of granite and dolomite parent rocks,as well as the strength and elastic modulus of mortar and concrete prepared with mechanism aggregates of the corresponding lithology,and the stress-strain curves of concrete were investigated.In this paper,a coarse aggregate and mortar matrix bonding assumption is proposed,and a prediction model for the elastic modulus of mortar is established by considering the lithology of the mechanism sand and the slurry components.An equivalent coarse aggregate elastic modulus model was established by considering factors such as coarse aggregate particle size,volume fraction,and mortar thickness between coarse aggregates.Based on the elastic modulus of the equivalent coarse aggregate and the remaining mortar,a prediction model for the elastic modulus of the two and three components of concrete in series and then in parallel was established,and the predicted values differed from the measured values within 10%.It is proposed that the coarse aggregate elastic modulus in highstrength concrete is the most critical factor affecting the elastic modulus of concrete,and as the coarse aggregate elastic modulus increases by 27.7%,the concrete elastic modulus increases by 19.5%.
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.
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Under the auspices of Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA28100405,XDA28020403)National Natural Science Foundation of China (No. 41771179, 42071275)+1 种基金Talents Training Project Supported by the Central Government for the Reform and Development of Local UniversitiesYoung Scientist Group Project of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences (No. 2022QNXZ02)
文摘The effective use of land in Northeast China is of great significance for ensuring national food security and regional rural revitalization.In this study,based on the survey data collected from Jilin Province,Northeast China,we analyzed the vacancy rates of rural homesteads in suburban,outer suburban,and remote villages,as well as the withdrawal intention of rural-settled farmers,urbansettled farmers,and farmers with urban and rural dual residency from vacant homesteads.From the perspective of farmers’perceptions,this study constructed a theoretical framework of the influence mechanism of their withdrawal intention and analyzed such mechanism by constructing a structural equation model.The results indicated that:1)rural homestead vacancy rates increased with distance from the village to the city.2)rural-settled farmers showed a low withdrawal intention for vacant rural homesteads,followed by urban and rural dual-residence farmers,and urban-settled farmers showed the highest withdrawal intention.3)the relative importance of the factors influencing withdrawal intention is in the following order:policy awareness>interest perception>living environment perception>family characteristics.Finally,this study discussed the reformation of the homestead system and rural homestead transition in Northeast China,which can provide policy support to increase the potential of cultivated land and promote sustainable rural development and urban-rural coordination.
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.
基金The National Science and Technology Support Planning,No.2012BAJ22B03
文摘Land use issue is an important constraining force to limit economic sustainable development of China. Urban and rural rapid expansion depletes valued land resources under the background of rapid urbanization. An extensive use pattern might cause a serious waste of land resources. The study on influencing mechanism of land intensive use （LIU） in China at the county level is a key tool for effective LIU practice and policy-making. This paper uses OLS model, Spatial Panel Lagged model and Spatial Panel Error model to quantitatively analyze the influencing mechanisms of five class factors and 17 variables supported by GIS （Geographic Information System） and MATLAB. And a comprehensive data set was devel- oped including physical geography and socio-economic information of 2286 counties. Meanwhile, the spatiotemporal pattern of LIU has discussed by means of GIS. The results show that Spatial Panel Data models are slightly superior to OLS model in terms of signifi- cance and confidence level. Regression results of these models indicate that industrialization, urbanization, economic development level, location, transportation and policy have significant impact on LIU of counties. The variables of physical geography are less significant than socio-economic variables. An ignored variable of historical factor, however, became the best significant factor. In the future, the LIU at the county level should take advantage of the new situation by enhancing favorable factors and reducing disadvantageous ones, which can be acquired by improving the entire level and quality of industrialization and urbanization. We argued that an efficient and complete land market and operating system should be built to reflect market-oriented activities at the first place, then, differential LIU regulation policies and measurements should be optimized according to regional differences. In the meantime, we should pay close attention to the carrying capacity of local resources and environments when conducting LIU practices.
基金Under the auspices of National Natural Science Foundation of China(No.41701151)MOE(Ministry of Education in China)Project of Humanities and Social Sciences(No.17YJCZH256)Doctoral Project of Tianjin Normal University(No.52XB1621)
文摘Spatial equality of access to basic public services, especially medical care services which are directly related to life safety, is the first step to achieve the goal of equalization of basic public services for all the people proposed by central government of China. Using the spatial analysis and the statistical analysis, this study evaluates the spatial differentiation of medical care facilities accessibility by constructing STT(Shortest Travel-Time) and SAI(Spatial Accessibility Index). And then this study explores the neighborhood effects on the medical care facilities accessibility in Beijing, with a particular focus on the effect of neighborhood migrant proportion by constructing spatial dependent regression model. The spatial accessibility analysis of medical care facilities show that the spatial distribution of medical care facilities was basically consistent with administrative regions but not with population demands. Bivariate LISA cluster maps identify that suburban areas are the overlapped clusters of high percent of migrants and limited medical care services. This is associated with the public service allocation rule in China, which stresses equality within urban areas and within rural areas but overlooks equality between urban areas and rural areas; and stresses local resident demands but overlooks migrant demands. To estimate the effects on medical care accessibility of neighborhood migrant proportion, spatial dependence models are applied due to spatial dependence of accessibility of medical care facilities. The regression results show that neighborhoods with high percent of migrants, even conditioning on neighborhood SES, are related to limited spatial accessibility of medical care services. Besides neighborhood characteristics, another important factor influencing spatial accessibility of medical care services is the process of spatial spillover effects. This indicates that the attenuate accessibility of medical care services for migrants is not only because of their own constraints but also because of their proximity to other disadvantaged neighborhoods. Therefore, it is urgently needed to increase the medical facilities in the suburban areas, to take into account migrants' demands and to reduce residential segregation between local residents and migrants for local governments to achieve the goal of equalization of medical care service.
基金National Key Research and Development Program of China,No.2018YFE0184300National Natural Science Foundation of China,No.41761115,No.41271203Key Research Projects of Graduate Students in Yunnan Normal University,No.ysdyjs2019166。
文摘Following climate change,changes in precipitation patterns and food security are major challenges faced by humans.However,research on how these changes in precipitation pattern impacts food supply is limited.This study aims to elucidate this impact and response mechanisms using precipitation data of a climate change-sensitive confluence zone of the southwest and southeast monsoons in Yunnan Province from 1988 to 2018.The results revealed that the precipitation pattern could be divided into three periods:abundant precipitation(Stage I,from 1988 to 2004),decreased precipitation(Stage II,from 2005 to 2015),and drought recovery(Stage III,from 2016 to 2018).Following the transition from Stage I to Stage II and from Stage II to Stage III,the area of precipitation changed significantly,accounting for 15.07%,13.87%,and 16.53%of Yunnan’s total area,for Stages I,II,and III,respectively.At the provincial level,a significant positive correlation was observed between precipitation and food production(r=0.535,P<0.01),and the correlation coefficient between precipitation and grain yield was higher than that between precipitation and meat and milk production.Based on a precipitation–grain yield transect and breakpoint detection method,key precipitation thresholds affecting grain yield were estimated as 700 and 1500 mm,respectively;when precipitation was<700,700–1500,and≥1500 mm,the correlation coefficients between precipitation and grain yield were 0.448(P<0.01),0.370(P<0.01),and–0.229(P>0.05),respectively.Based on the precipitation thresholds,Yunnan Province can be divided into precipitation surplus,precipitation equilibrium,and precipitation deficit regions,corresponding countermeasures to stabilize grain yield were proposed for each of these regions.The threshold effect of precipitation on grain yield is controlled by molecular-level water–crop mechanisms,in which reactive oxygen species,a by-product of plant aerobic metabolism,plays a key regulatory role.
基金Supported by the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019 QZKK 0805)the National Natural Science Foundation of China(No.U 21 A 2018)the Foundation of Department of Qinghai Science&Technology(No.2020-ZJ-T 06)。
文摘The Qaidam Basin(QB)is a concentrated distribution area and chemical industrial bases of salt lakes in China.Lakes in the QB have been expanding during the past 20 years.Rapid lake expansion resulted in some considerable scientific issues on the protection of salt lake resources and infrastructure,and monitoring of hydrological processes at the lake-basin scale.Although the spatial-temporal trends of lake changes on the Qinghai-Tibet Plateau(QTP)have been well documented,the underlying influencing mechanism and hydrogeological implications of rapid lake changes in the QB are not well understood.Three lakes in the northern QB were selected to investigate lake water level fluctuations on different time scales based on extensive in-situ monitoring and satellite observations.The influencing mechanism and hydrogeological implications of rapid changes of terminal lakes were discussed in combination with the reported increasing precipitation rate and mass balance of glaciers in the northern QTP.Results reveal the following:(1)the fluctuation pattern of Sugan Lake was asynchronous and out of phase with that of Xiao Qaidam and Toson lakes during the monitoring period;(2)Sugan Lake water rose gradually,and the rise interval was from late April to early July.In contrast,Xiao Qaidam and Toson lakes took on a rapid and steep rise,and the rise intervalwas from late July to September;(3)the influencing mechanisms for rapid lake fluctuations are controlled by different factors:glacier and snow melting with increasing temperature for Sugan Lake and increasing precipitation for Xiao Qaidam and Toson lakes;(4)in accordance with different intervals and influencing mechanisms of rapid lake expansions in the QB,hydrological risk precaution of lakes and corresponding river catchments was conducted in different parts of the basin.This study provided an important scientific basis for assessing the hydrological process and hydrological risk precaution,and protection of salt lake resources along with rapid lake expansions in the arid area.
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.
