Hydrochemical Constraints on the Flowing Paths of Groundwater in Limestone Reservoirs beneath the Pingdingshan Coalfield in North China

The karst groundwater of Cambrian limestone may become an important water source for industry and agriculture in the Pingdingshan area,and is also a potential threat to mining safety.Therefore,to find out the origin,flow paths,and hydrogeochemical processes of karst groundwater beneath the Pingdingshan coalfield,a total of 16 water samples were collected.Our findings confirmed that the karst groundwater is mainly recharged by precipitation.The precipitation can directly supply the deep aquifer of the karst water system through the southwest limestone outcrops,and this area mostly includes the southern part of mines No.11,No.9,and the hidden outcrops in the southern part of mine No.2.What is more,the areas adjacent to the synclinal axis,including mines No.10,No.12,and No.8,may be the main discharge areas.A mixing model of^(87)Sr/^(86)Sr and Sr showed that in the southwest Pingdingshan coalfield,the proportion of precipitation decreased gradually from the recharge area to the discharge area,ranging from 89.1%to 17.1%.Besides,the northeast Pingdingshan coalfield is another recharge area for the whole karst system,thus,the infiltrating groundwater will indirectly supply the deep aquifer through Quaternary deposition near the mine No.13.Our research results can provide theoretical support for the prevention and control of groundwater disasters and the development and utilization of regional groundwater resources in the coalfield in Northern China.

Mechanical response and dilatancy characteristics of deep marble under different stress paths:A sight from energy dissipation

Dilatancy is a fundamental volumetric growth behavior observed during loading and serves as a key index to comprehending the intricate nonlinear behavior and constitutive equation structure of rock.This study focuses on Jinping marble obtained from the Jinping Underground Laboratory in China at a depth of 2400 m.Various uniaxial and triaxial tests at different strain rates,along with constant confining pressure tests and reduced confining pressure tests under different confining pressures were conducted to analyze the mechanical response and dilatancy characteristics of the marble under four stress paths.Subsequently,a new empirical dilatancy coefficient is proposed based on the energy dissipation method.The results show that brittle failure characteristics of marble under uniaxial compression are more obvious with the strain rate increasing,and plastic failure characteristics of marble under triaxial compression are gradually strengthened.Furthermore,compared to the constant confining pressure,the volume expansion is relatively lower under unloading condition.The energy dissipation is closely linked to the process of dilatancy,with a rapid increase of dissipated energy coinciding with the beginning of dilatancy.A new empirical dilatancy coefficient is defined according to the change trend of energy dissipation rate curve,of which change trend is consistent with the actual dilatancy response in marble under different stress paths.The existing empirical and theoretical dilatancy models are analyzed,which shows that the empirical dilatancy coefficient based on the energy background is more universal.

Spatiotemporal variations,influencing factors,and configurational promotion paths of energy efficiency in China’s cities

The promotion of energy efficiency(EE)helps address energy constraints and promote environmental sustainability.This study comprehensively explores the spatiotemporal variations,influencing factors,and configuration promotion paths of EE in 284 Chinese cities during 2003‒2019 using the global super-efficiency minimum distance to strong efficient frontier(G-S-MinDS),exploratory spatial data analysis(ESDA),multiscale geographically weighted regression(MGWR),and fuzzy set qualitative comparative analysis(fsQCA)methods.The findings are:①China’s cities have an annual average EE of 0.658 with a growth rate of 0.53%,showing considerable promotion potential.②Industrial structure optimization,population agglomeration,economic development,and increased green coverage contribute positively,while government intervention and openness hinder China’s urban EE.③Four configurational promotion paths for enhancing China’s urban EE are identified,where among those paths population density is a core condition,while government intervention is not.This study provides valuable insights into substantially improving urban EE,emphasizing the need for targeted policies to address energy and environmental crises in China.

Characteristics and Mechanisms of Persistent Wet–Cold Events with Different Cold-air Paths in South China

We investigate the characteristics and mechanisms of persistent wet–cold events(PWCEs)with different types of coldair paths.Results show that the cumulative single-station frequency of the PWCEs in the western part of South China is higher than that in the eastern part.The pattern of single-station frequency of the PWCEs are“Yangtze River(YR)uniform”and“east–west inverse”.The YR uniform pattern is the dominant mode,so we focus on this pattern.The cold-air paths for PWCEs of the YR uniform pattern are divided into three types—namely,the west,northwest and north types—among which the west type accounts for the largest proportion.The differences in atmospheric circulation of the PWCEs under the three types of paths are obvious.The thermal inversion layer in the lower troposphere is favorable for precipitation during the PWCEs.The positive water vapor budget for the three types of PWCEs mainly appears at the southern boundary.

Experimental study on permeability evolution of deep high-stressed coal under major horizontal stress unloading paths

Both bulk stress(σ_(i i))and stress path(SP)significantly affect the transportation characteristics of deep gas during reservoir pressure depletion.Therefore,the experimental study of horizontal stress unloading on seepage behavior of gas-bearing coal under constantσi i-constraints is performed.The results show that coal permeability is affected by horizontal stress anisotropy(σ_(H)≠σh),and the contribution of minor horizontal stress to permeability is related to the differential response of horizontal strain.The slippage phenomenon is prominent in deep high-stress regime,especially in low reservoir pressure.σ_(i i)and SP jointly determine the manifestation of slippage effect and the strength of stress sensitivity(γ)of permeability.Deep reservoir implies an incremental percentage of slip-based permeability,and SP weakens the slippage effect by changing the elastic–plastic state of coal.However,γis negatively correlated with slippage effect.From the Walsh model,narrow(low aspect-ratio)fractures within the coal under unloading SP became the main channel for gas seepage,and bring the effective stress coefficient of permeability(χ)less than 1 for both low-stress elastic and high-stress damaged coal.With the raise of the effective stress,the effect of pore-lined clay particles on permeability was enhanced,inducing an increase inχfor highstress elastic coal.

Strategies and Paths for Constructing Rural Landscape Ecological Security Pattern in the Context of Rural Revitalization

It is one of the fundamental research contents of rural revitalization by constructing a ecological security pattern of rural landscape,providing important basis for scientifically formulating rural spatial planning and sustainable rural development.The research on ecological security patterns of landscape at home and abroad is mainly focused on urban areas.In the context of rural revitalization,the research on strategies and paths for constructing the ecological security pattern of rural landscapes aims to provide important references for the overall planning and design of rural areas and the optimization of rural resource allocation.Using 3S(GPS,RS,GIS)technology methods,this paper systematically analyzes and elaborates on the construction strategies and paths of rural water ecological security pattern,rural biological protection security pattern,rural geological disaster security pattern,and local cultural landscape security pattern.Through the comprehensive superposition of the patterns,a comprehensive ecological security pattern of rural landscape is finally constructed.In the process of constructing and improving the ecological security pattern of rural landscape,emphasis is placed on top-level design,long-term planning,multi-party participation,mechanism improvement,technological innovation,and the strategy of“integrating knowledge with action”.

New paths and research directions in CO_(2) conversion by electro-, photoand plasma catalysis

CO_(2) conversion into value-added products by electro-, photoand plasma catalysis under mild operating conditions(ambient temperature and pressure) is an emerging area to achieve carbon circularity by producing chemicals and fuels using directly renewable energy. Among all CO_(2) conversion approaches, the electrocatalytic reduction of CO_(2) is the most mature technology, capable of achieving high productivity(i.e. high current densities) at large scale, especially for producing carbon monoxide(CO), but with many examples showing selectivity to C_(2) carbon products.

Green transformation paths of resource-based cities in China from the configuration perspective

Green transformation is an unavoidable choice for resource-based cities(RBCs)that face resource depletion and environmental pollution.Existing research has focused primarily on specific RBCs,making it challenging to apply green transformation strategies universally across cities.The fuzzy set qualitative comparative analysis(fsQCA)is a combination of qualitative and quantitative analyses that can handle multiple concurrent causality problems and determine how different conditions combine into configurations and generate an outcome.Thus,to address this gap,in this study,we established a research framework for green transformation and utilized the fsQCA to examine the configurations of 113 RBCs in China.By incorporating the element of time,this study explored the dynamic evolution of solutions in 2013,2016,and 2019.The main findings indicate that individual elements do not constitute the necessary conditions for improving the green transformation efficiency(GTE),and the systematic combination of multiple conditions is an effective path for realizing the improvement of the GTE in RBCs.Green transformation paths of RBCs exhibit the same destination through different paths.Additionally,the combination of system environment elements and system structure elements is both complementary and alternative.Differences in RBCs have led to various factor combinations and development paths,but there are some similarities in the key elements of the factor combinations at different stages.Economic environment,government support,and technological innovation are key factors that universally enhance the GTE in RBCs.These insights can assist city managers in formulating policies to drive green transformation and contribute to a better theoretical understanding of green transformation paths in RBCs.

Evolution of mechanical parameters of Shuangjiangkou granite under different loading cycles and stress paths

Surrounding rocks at different locations are generally subjected to different stress paths during the process of deep hard rock excavation.In this study,to reveal the mechanical parameters of deep surrounding rock under different stress paths,a new cyclic loading and unloading test method for controlled true triaxial loading and unloading and principal stress direction interchange was proposed,and the evolution of mechanical parameters of Shuangjiangkou granite under different stress paths was studied,including the deformation modulus,elastic deformation increment ratios,fracture degree,cohesion and internal friction angle.Additionally,stress path coefficient was defined to characterize different stress paths,and the functional relationships among the stress path coefficient,rock fracture degree difference coefficient,cohesion and internal friction angle were obtained.The results show that during the true triaxial cyclic loading and unloading process,the deformation modulus and cohesion gradually decrease,while the internal friction angle gradually increases with increasing equivalent crack strain.The stress path coefficient is exponentially related to the rock fracture degree difference coefficient.As the stress path coefficient increases,the degrees of cohesion weakening and internal friction angle strengthening decrease linearly.During cyclic loading and unloading under true triaxial principal stress direction interchange,the direction of crack development changes,and the deformation modulus increases,while the cohesion and internal friction angle decrease slightly,indicating that the principal stress direction interchange has a strengthening effect on the surrounding rocks.Finally,the influences of the principal stress interchange direction on the stabilities of deep engineering excavation projects are discussed.

The Opportunities,Dilemmas,and Paths for the Development of Adult Higher Education in the New Era

This paper comprehensively analyzes the development opportunities and realistic dilemmas faced by adult higher education in China in the new era,and puts forward corresponding strategies as solutions.With the construction of a learning society,the development of digital technology,and the popularization of the concept of lifelong learning,adult higher education has unprecedented development opportunities.At the same time,these forms of education are facing a series of dilemmas due to challenges such as unsound guarantee mechanisms and traditional enrollment competition.Through the establishment of perfect legal and policy guarantees,transformation of school running mode,meeting the diversified needs of learners,and other multi-faceted measures,the development of adult higher education can be effectively promoted to meet the needs of individual and social development.

A Study on the Problems and Solution Paths in the Conduct of Elderly Competency Assessment

Exploring the problems existing in the process of carrying out an elderly competency assessment aims to provide useful references for its improvement.Starting from the importance of elderly competency assessment in the field of elderly services,this paper analyses the problems in the process of carrying out elderly competency assessment and explores the corresponding solutions.The analysis finds that problems in the process of carrying out elderly competency assessment are inevitable,but as long as the study continues to explore and innovate and actively seek solution paths,the study will be able to overcome these difficulties and provide the elderly with better and more efficient elderly services.

The Existing Problems and Optimization Paths of Digital Textbooks Under Background of Internet

With the rapid development of information technology,the combination of terminal technology,big data and mobile Internet and textbooks has become an irresistible trend in the modern education field.Under the context of the Internet,carrying out education and teaching activities based on digital textbooks can give full play to the rich media,openness and interaction of digital textbooks,broaden students′horizon,enrich students′knowledge,and promote the improvement of students′ability and all-round development.However,in the specific teaching practice,there are also problems such as old compilation ideas,single compilation mode and low efficiency of personalized learning.Therefore,schools and teachers need to constantly innovate the presentation and arrangement of digital textbooks,strengthen technical support,deepen students′understanding of the teaching content of digital textbooks,promote the comprehensive development of students and improve the effectiveness of digital textbook teaching.

Research on the Improvement and Innovation Paths of Teaching Quality in Private Universities in Zhejiang Province in the Digital Era

In the digital era,the education and teaching of private undergraduate universities in China are undergoing innovative reform.This article uses the literature review method to conduct a survey and research on the quality of teaching resources,teaching platforms,and literature reserves,and proposes a series of strategies and innovative paths to improve the teaching quality of private undergraduate universities.The research results show that the rational use of digital technology can improve the quality of education and teaching,and achieve innovative development in education and teaching.The research results have certain theoretical value and guiding significance for the teaching reform of private undergraduate universities under the background of digital teaching.

The Influencing Factors and Improvement Paths of Applied Talent Training Mode under the Digital Informatization

This study takes the human resource management major of Guangzhou Institute of Science and Technology as an example to discuss the factors influencing the applied talent training mode and improvement paths under digital informatization.The research points out that digital informatization poses new challenges and opportunities to higher education and requires the applied talent training mode to practice and innovate.This study identified five key influencing factors of the applied talent training mode under digital informatization:curriculum setting,teaching methods,faculty structure,practical teaching,and student training.This research presents the improvement paths,including optimizing curriculum settings,innovating teaching methods,adjusting teacher structure,improving practical teaching,and creating student training.Implementing these paths will help students master the latest knowledge and skills of digital informatization,improve their practical ability and innovative thinking to meet the social demand for human resource management professionals,and promote the development of higher education system.

Differentiated Paths of Regional Green Development Driven by Industrial Enterprise Innovation

A fundamental shift in the regional development pattern is crucial to achieving a comprehensive green transformation in China.Currently,innovation-driven green development is a significant strategic option for regional development.As the main body of innovation and the basic unit of regional composition,enterprises have a profound impact on the development of regional economy,society,ecology,and other aspects.However,considering China’s vast territory and significant regional differences in natural environment and industrial structure,it’s necessary to further explore the specific impact paths of regional green development driven by enterprise innovation.Therefore,taking industrial enterprises as an example,based on the panel data of 30 provinces in China from 2016 to 2020,this study verifies the impact of industrial enterprise innovation on the regional green development level by constructing a parallel multiple mediating effect model and dividing the economy into eastern,central,and western regions to discuss the specific impact paths.The results show that industrial enterprise innovation has a significant positive effect on regional green development level,via different influencing paths in each region:(1)The eastern region improves the regional green development level by narrowing the urban-rural income gap;(2)The central region improves the regional green development level by reducing resource dependence;and(3)The western region raises the regional green development level by improving the rationalization of industrial structure.

Construction of Ideological and Political Education in English Teacher Education Courses in Local Normal Universities:Objectives,Connotations,and Implementation Paths

The integration of ideological and political education into university curricula represents a new trend in holistic,comprehensive,and all-around education.The concept of“ideological and political education in English teacher education courses”embodies an interdisciplinary approach to curriculum reform.Grounded in the principle of fostering moral integrity,it aims to create high-quality courses by seamlessly integrating the transmission of knowledge and skills with the guidance of ideological values.This study explores the status quo,significance,and implementation pathways for integrating ideological and political education into English teacher education courses,providing valuable insights for future curricular development.

Evaluation of Comprehensive Carrying Capacity of Tourist Cities and Optimization Paths:Based on the Comparison between East and West Guangdong

Seven tourist cities in eastern and western Guangdong were selected as the research objects to establish an evaluation index system of urban comprehensive carrying capacity,and its changing laws were analyzed.It was found that the comprehensive carrying capacities of cities in eastern and western Guangdong showed a trend of“first increasing and then decreasing”from 2015 to 2021,and reached the highest point in 2019,but there were significant differences among regions.From the perspective of spatial distribution,the comprehensive carrying capacities of cities in eastern and western Guangdong generally presented the law of high on both sides and low in the middle.In terms of the proportion of comprehensive carrying capacity of tourist cities,the larger part was always the carrying capacity of infrastructure and public services.The value of economic carrying capacity showed a trend of“first increasing and then decreasing”,while the value of environmental carrying capacity was always on the increase,and the value of tourism resources carrying capacity was basically stable.Finally,according to the analysis results,this paper put forward the optimization paths for comprehensive carrying capacities of tourist cities in eastern and western Guangdong from following four aspects:coordinating regional development,rationally utilizing natural resources,adjusting economic structure and adhering to the sustainable development concept.

Energy conversion of rocks in process of unloading confining pressure under different unloading paths

Based on energy theory and tests of rocks with initial confining pressures of 10, 20 and 30 MPa under different unloading paths, the processes of strain energy conversion were investigated. The absorbing strain energy for axial compression, the dissipating strain energy for plastic deformation and cracks propagation, the expending strain energy for circumferential deformation, and the storing and releasing elastic strain energy were considered. Unloading paths included the condition of fixing axial pressure and unloading axial pressure, increasing axial pressure and unloading confining pressure, as well as unloading axial pressure and confining pressure simultaneously. Results show that expending strain energy for circumferential deformation has mainly evolved from absorbing strain energy for axial compression in three unloading paths during unloading processes. Dissipating strain energy is significantly increased only near the peak point. The effect of initial confining pressure on strain energy is significantly higher than that of unloading path. The strain energy is linearly increased with increasing initial confining pressure. The unloading path and initial confining pressure also have great influence on the energy dissipation. The conversion rate of strain energy in three paths is increased with increasing initial confining pressure, and the effect of initial confining pressure on conversion rate of strain energy is related with the unloading paths.

The influence of sea water velocity variation on seismic traveltimes,ray paths,and amplitude

The main factors affecting seismic exploration is the propagation velocity of seismic waves in the medium. In the past, during marine seismic data processing, the propagation velocity of sea water was generally taken as a constant 1500 m/s. However, for deep water exploration, the sound velocity varies with the season, time, location, water depth, ocean currents, and etc.. It also results in a layered velocity distribution, so there is a difference of seismic traveltime, ray paths, and amplitude, which affect the migration imaging results if sea water propagation velocity is still taken as constant for the propagation wavefield. In this paper, we will start from an empirical equation of seismic wave velocity in seawater with changes of temperature, salinity, and depth, consider the variation of their values, build a seawater velocity model, and quantitatively analyze the impact of seawater velocity variation on seismic traveltime, ray paths, and amplitude in the seawater velocity model.

Research on the Current Status, Paths and Countermeasures of Family Farm Development in China——Investigation and Analysis of Hubei Province

The Chinese family farm is the most important new micro subject in the construction and development of modern agriculture in China. The investigation and analysis of the actual situation of Hubei Province showed that since the implementation of the household contract management system in rural areas, the family farm has followed the track of gradual development, breakthrough development and normal standardization development. In order to promote the family farm to develop rapidly, orderly and healthily, work must be well done to land circulation, scale management, financial support, financial subsidy, cultivation of leading talents and professional farmers, and providing all-round services.