Equipment management is one of the important parts of business administra- tion of coal. Most of coal mines take no account of their equipment management, and have no comprehensive and effective evaluation index syste...Equipment management is one of the important parts of business administra- tion of coal. Most of coal mines take no account of their equipment management, and have no comprehensive and effective evaluation index system. Based on the analysis of the equipment evaluation measures of reform and the applications, the paper built up a comprehensive and effective evaluation index system of coal mine equipment, and im- proved the evaluation method with the use of fuzzy theory, analytic hierarchy process and entropy method.展开更多
With the global economy integration and progress in energy transformation,it has become a general trend to surpass national boundaries to achieve wider and optimal energy resource allocations.Consequently,there is a c...With the global economy integration and progress in energy transformation,it has become a general trend to surpass national boundaries to achieve wider and optimal energy resource allocations.Consequently,there is a critical n eed to adopt scie ntific approaches in assessi ng cross-border power grid interconnection projects.First,con sidering the promotion of large-scale renewable energy resources and improvements in system adequacy,a comprehensive assessment index system,including costs,socio-economic benefits,environmental benefits,and technical benefits,is established in this study.Second,a synthetic assessment framework is proposed for cross-border power grid interconnection projects based on the index system comprising cost-benefit analysis,with market and network simulations,iterative methods for indicator weight evaluation,and technique for order preferenee by similarity to an ideal solution(TOPSIS)method for the project rankings.Fin ally,by assessi ng and comparing three cross-border projects betwee n Europe and Asia,the proposed index system and assessment framework have been proved to be effective and feasible;the results of this system can thus support investment decision-making related to such projects in the future.展开更多
To better reduce the carbon emissions of a park-integrated energy system(PIES),optimize the comprehensive operating cost,and smooth the load curve,a source-load flexible response model based on the comprehensive evalu...To better reduce the carbon emissions of a park-integrated energy system(PIES),optimize the comprehensive operating cost,and smooth the load curve,a source-load flexible response model based on the comprehensive evaluation index is proposed.Firstly,a source-load flexible response model is proposed under the stepped carbon trading mechanism;the organic Rankine cycle is introduced into the source-side to construct a flexible response model with traditional combined heat and power(CHP)unit and electric boiler to realize the flexible response of CHP to load;and the load-side categorizes loads into transferable,interruptible,and substitutable loads according to the load characteristics and establishes a comprehensive demand response model.Secondly,the analytic network process(ANP)considers the linkages between indicators and allows decision-makers to consider the interactions of elements in a complex dynamic system,resulting in more realistic indicator assignment values.Considering the economy,energy efficiency,and environment,the PIES optimization operation model based on the ANP comprehensive evaluation index is constructed to optimize the system operation comprehensively.Finally,the CPLEX solver inMATLABwas employed to solve the problem.The results of the example showthat the source-load flexible response model proposed in this paper reduces the operating cost of the system by 29.90%,improves the comprehensive utilization rate by 15.00%,and reduces the carbon emission by 26.98%,which effectively enhances the system’s economy and low carbon,and the comprehensive evaluation index based on the ANP reaches 0.95,which takes into account the economy,energy efficiency,and the environment,and is more superior than the single evaluation index.展开更多
Climate change severely challenges our ecosystem and society,affecting urban residents’socioeconomic activities.Thus,assessing severe weather risk is crucial for evaluating urban sustainability;understanding trends,c...Climate change severely challenges our ecosystem and society,affecting urban residents’socioeconomic activities.Thus,assessing severe weather risk is crucial for evaluating urban sustainability;understanding trends,causes,and impacts on socioeconomic development;and supporting the United Nations Sustainable Development Goal(SDG)13.Using meteorological data from 1980 to 2020,we investigate five disaster-causing severe weather events in China and construct a comprehensive index of extreme climate risk(CIECR)at the county,city,province,and national levels.The CIECR can identify high-risk regions and primary severe weather events and provide early warnings.We empirically test the impact of extreme climate risks on agricultural production,industrial structure,and labor employment.The results show high risks in Xinjiang,northern Inner Mongolia,and southern regions,with high temperatures,low temperatures,and high winds as the leading risks.At the national level,the extreme climate risk fluctuates,indicating climate warming.While risks reduce agricultural production and employment,they promote modern agriculture,industrial production,and urbanization.The novelty of the study lies in its development of the county-level CIECR,which can capture heterogeneity characteristics and provide microdata support for urban climate change research and efforts toward SDG 13.This study aids in mitigating climate risks;responding to climate change;and comprehensively analyzing the causes,trends,and impacts of extreme climate risks.展开更多
Background:Accurate complication reporting in endourology remains challenging,with the Clavien-Dindo Classification and Comprehensive Complication Index being the most commonly used systems.This study aimed to compare...Background:Accurate complication reporting in endourology remains challenging,with the Clavien-Dindo Classification and Comprehensive Complication Index being the most commonly used systems.This study aimed to compare surgical outcomes and complication reporting in ureterolithotripsy(URL),percutaneous nephrolithotomy(PCNL),and extracorporeal shock wave lithotripsy(ESWL)using both systems.Methods:This prospective,single-center,non-interventional study included 473 patients undergoing URL,PCNL,or ESWL from October 2022 to October 2024.Demographic,stone-related,and procedural variables were recorded.Complications were classified using the CDC,and cumulative morbidity was assessed using CCI.Statistical analyses,including univariate and multivariate regression,were performed to identify predictors of higher CCI scores.Results:PCNL was associated with the highest complication rates,including an 11%transfusion rate.ESWL had the lowest complication burden,while URL demonstrated intermediate risk.CCI scores correlated positively with length of stay(LOS;r=0.47),highlighting its ability to capture overall morbidity.Multivariate analysis identified stone size,operating time,and positive urine culture as significant predictors of higher CCI scores.The CCI provided a more comprehensive representation of morbidity compared to the CDC.Conclusions:CCI demonstrates superior sensitivity in evaluating postoperative morbidity compared to CDC,particularly in more invasive procedures such as PCNL.Standardized reporting frameworks incorporating CCI may enhance surgical outcome assessment in endourology.展开更多
BACKGROUND Detailed data on the relation of post-operative complications with clinical outcomes after simultaneous pancreas-kidney(SPK)transplantation is lacking.AIM To compare Clavien-Dindo classification(CDC)and com...BACKGROUND Detailed data on the relation of post-operative complications with clinical outcomes after simultaneous pancreas-kidney(SPK)transplantation is lacking.AIM To compare Clavien-Dindo classification(CDC)and comprehensive complication index(CCI)in predicting outcomes after SPK.METHODS Data for patients undergoing SPK between 1999-2019 were analyzed.Information on recipients’baseline characteristics,peri-operative management and postoperative complications were collated.Length of hospital stay(LOS)was the primary study outcome,and the associations with CDC and CCI were evaluated using Spearman’s(ρ)correlation coefficients.RESULTS In the study period,data were available for 128 patients(female n=44,34.4%).Sixty-nine patients had at least one complication with the highest CDC grade of I,II,III,and IV in 8(6.3%),22(17.2%),32(25%),and 7(5.5%)patients,respectively. The mean LOS was 21.4 ± 17.7 days. Both classification systems were correlated with LOS, yet CCI was stronger(Spearman’s ρ: 0.694 vs 0.602, P < 0.001). Female patients (P = 0.019) and patients with pre-transplant cardiovascularevents (P = 0.02) had longer LOS. After adjusted multivariable analysis, the link between LOS and both theCDC and CCI remained relevant. CCI had a superior fit compared to CDC (r2 = 0.729 vs r2 = 0.481), with every 10CCI points being associated with a 5.27 day (P < 0.001) increased LOS.CONCLUSIONThis study showed that the CCI was better linked with LOS compared to CDC and might represent a useful scoreto evaluate the overall burden of postoperative complications in patients undergoing SPK.展开更多
Water quality is a pressing issue affecting the sustainable development of lakes.To elucidate the spatial and temporal characteristics of water quality in Bos ten Lake,China,this study constructed a comprehensive wate...Water quality is a pressing issue affecting the sustainable development of lakes.To elucidate the spatial and temporal characteristics of water quality in Bos ten Lake,China,this study constructed a comprehensive water quality index(CWQI) based on key water quality indicators,utilizing water quality data collected from 17 sampling sites spaning from 2011 to 2019.Key water quality indicators were determined using factor analysis,and the spatial and temporal characteristics of key water quality indicators and the CWQI were examined using multivariate statistical analysis.The key water quality indicators included pH,chemical oxygen demand(COD),water transparency(SD),NO3-,total dissolved solids(TDS),Cl-,SO42-,and electrical conductivity(EC).Furthermore,the contribution rates of all water quality indicators to the water quality were quantitatively elucidated using the SHapley Additive explanations(SHAP) values,thereby validating the factor analysis outcomes.Among the eight key water quality indicators,the COD had the most significant influence on the water quality of Bos ten Lake.The water quality condition of Bosten Lake has remained at Class Ⅲ from 2011 to 2019(CWQI ranging from3.19 to 3.90).The water quality of Bos ten Lake was characterized by distinct regional differences that arose from hydrodynamic processes within the lake and upstream water quality.The southwestern region exhibited the best water quality(mean CWQI of 3.47),whereas the northwestern region exhibited the worst(mean CWQI of 3.58).It is crucial to acknowledge that alongside the increase in industrial and agricultural effluent discharge monitoring,a series of ecological restoration projects for the lake basin have been initiated.Over time,the water quality of Bosten Lake showed gradual improvement(improvement rate of CWQI at 0.05/a).This study provides a critical scientific basis for enhancing the understanding and effective management of water quality in the Bosten Lake Basin through a comprehensive analysis of its spatial and temporal evolution and driving mechanisms.展开更多
The purpose of establishing a comprehensive evaluation index system of agricultural information service in rural areas is mainly to evaluate the level of agricultural information service reasonably, comprehensively an...The purpose of establishing a comprehensive evaluation index system of agricultural information service in rural areas is mainly to evaluate the level of agricultural information service reasonably, comprehensively and scientifically. In establishing the comprehensive evaluation index system of agricultural information service, some principles should be followed, i.e. operability, independence, safety and universality. At present, when constructing the comprehensive evaluation index system of agricultural information service, the comprehensive evaluation is mainly carried out around the basic service facilities of agricultural information, the internal and external environment during the construction of agricultural information, the data of agricultural information construction and the work of agricultural information construction, so as to ensure that the comprehensive evaluation index system of agricultural information service is practical, reasonable, comprehensive and scientific.展开更多
The Yongding New River is essential for the water supplies of Tianjin.To date,there is no comprehensive report that assesses the year-round water quality of the Yongding New River Main stream.Moreover,little attention...The Yongding New River is essential for the water supplies of Tianjin.To date,there is no comprehensive report that assesses the year-round water quality of the Yongding New River Main stream.Moreover,little attention has been given to determining a combined weight for improving the traditional comprehensive water quality identification index(ICWQII)by the game theory.Seven water quality parameters were investigated monthly along the main stream of the Yongding New River from May 2018 to April 2019.Organic contaminants and nitrogen pollution were mainly caused by point sources pollution,and the total phosphorus mainly by non-point source pollution.Dramatic spatio-temporal variations of water quality parameters were jointly caused by different pollutant sources and hydrometeorological factors.In terms of this study,an improved comprehensive water quality identification index(ICWQII)based on entropy weight or variation coefficient and traditional CWQII underestimated the water qualities,and an ICWQII based on the superstandard multiple method overvalued the assessments.By contrast,water qualities assessments done with an ICWQII based on the game theory matched perfectly with the practical situation.The ICWQII based on game theory proposed in this study takes into account not only the degree of disorder and variation of water quality data,but also the influence of standard-exceeded pollution indicators,whose results are relatively reasonable.All findings and the ICWQII based on game theory can provide scientific support for decisions related to the water environment management of the Yongding New River and other waters.展开更多
Based on the ETM remote sensing images of Guangzhou City in 2014, the spatial distribution results o f three environmental factors including vegetation coverage(NDVI), soil index(vegetation index of bare soil) and sl ...Based on the ETM remote sensing images of Guangzhou City in 2014, the spatial distribution results o f three environmental factors including vegetation coverage(NDVI), soil index(vegetation index of bare soil) and sl ope were obtained. By using comprehensive index method, the normalized environmental factors were weighted and superimposed, and the fi nal evaluation results of ecological environment in Guangzhou City were obtained. The results showed that overall situation of natural ecological environment in Guangzhou was not optimistic, that is, the area of land with bad, moderate, good and superior environment accounted for 59.70%, 35.79%, 4.50% and around 0.01% of total area of land in Guangzhou City respectively. Ecological environment was generally poor in the central urban districts in the south of Guangzhou City, while it was relatively better in the north and northeast. Attaching importance to the constr uction of greenbelts and greenways is an effective way to improve regional environmental quality and natural ecological e nvironment level.展开更多
In order to further improve the utility of unmanned aerial vehicle(UAV)remote-sensing for quickly and accurately monitoring the growth of winter wheat under film mulching, this study examined the treatments of ridge m...In order to further improve the utility of unmanned aerial vehicle(UAV)remote-sensing for quickly and accurately monitoring the growth of winter wheat under film mulching, this study examined the treatments of ridge mulching,ridge–furrow full mulching, and flat cropping full mulching in winter wheat.Based on the fuzzy comprehensive evaluation (FCE) method, four agronomic parameters (leaf area index, above-ground biomass, plant height, and leaf chlorophyll content) were used to calculate the comprehensive growth evaluation index (CGEI) of the winter wheat, and 14 visible and near-infrared spectral indices were calculated using spectral purification technology to process the remote-sensing image data of winter wheat obtained by multispectral UAV.Four machine learning algorithms, partial least squares, support vector machines, random forests, and artificial neural network networks(ANN), were used to build the winter wheat growth monitoring model under film mulching, and accuracy evaluation and mapping of the spatial and temporal distribution of winter wheat growth status were carried out.The results showed that the CGEI of winter wheat under film mulching constructed using the FCE method could objectively and comprehensively evaluate the crop growth status.The accuracy of remote-sensing inversion of the CGEI based on the ANN model was higher than for the individual agronomic parameters, with a coefficient of determination of 0.75,a root mean square error of 8.40, and a mean absolute value error of 6.53.Spectral purification could eliminate the interference of background effects caused by mulching and soil, effectively improving the accuracy of the remotesensing inversion of winter wheat under film mulching, with the best inversion effect achieved on the ridge–furrow full mulching area after spectral purification.The results of this study provide a theoretical reference for the use of UAV remote-sensing to monitor the growth status of winter wheat with film mulching.展开更多
Wetland park is an important mode of wetland protection, meanwhile, construction of comprehensive index system has become the hotspot and keystone of the researches on Wetland Parks. Basing on different development st...Wetland park is an important mode of wetland protection, meanwhile, construction of comprehensive index system has become the hotspot and keystone of the researches on Wetland Parks. Basing on different development stages, this paper firstly divided the Wetland Parks into three categories, including the start-up stage, the development stage and the refinement stage. And then screened and identified the direction and keypoints of comprehensive evaluation for wetland parks in different development stages using expert scoring, questionnaire and analytic hierarchy process(AHP).展开更多
Natural gas hydrates(hereinafter referred to as hydrates)are a promising clean energy source.However,their current development is far from reaching commercial exploitation.Reservoir stimulation tech-nology provides ne...Natural gas hydrates(hereinafter referred to as hydrates)are a promising clean energy source.However,their current development is far from reaching commercial exploitation.Reservoir stimulation tech-nology provides new approaches to enhance hydrate development effectiveness.Addressing the current lack of quantitative and objective methods for evaluating the fracability of hydrate reservoirs,this study clarifies the relationship between geological and engineering fracability and proposes a comprehensive evaluation model for hydrate reservoir fracability based on grey relational analysis and the criteria importance through intercriteria correlation method.By integrating results from hydraulic fracturing experiments on hydrate sediments,the fracability of hydrate reservoirs is assessed.The concept of critical construction parameter curves for hydrate reservoirs is introduced for the first time.Additionally,two-dimensional fracability index evaluation charts and three-dimensional fracability construction condition discrimination charts are established.The results indicate that as the comprehensive fracability index increases,the feasibility of forming fractures in hydrate reservoirs improves,and the required normalized fracturing construction parameters gradually decrease.The accuracy rate of the charts in judging experimental results reached 89.74%,enabling quick evaluations of whether hydrate reservoirs are worth fracturing,easy to fracture,and capable of being fractured.This has significant engineering implications forthehydraulicfracturingof hydratereservoirs.展开更多
In the western Sichuan Basin,the Permian Qixia Fm grained dolomite reservoirs are currently the new focus of natural gas exploration and development.The Qixia Fm is characterized by developed dissolved vugs and fractu...In the western Sichuan Basin,the Permian Qixia Fm grained dolomite reservoirs are currently the new focus of natural gas exploration and development.The Qixia Fm is characterized by developed dissolved vugs and fractures,low matrix porosity and strong heterogeneity,so evaluation faults tend to occur if reservoir effectiveness is evaluated by means of the traditional porosity evaluation,and the consequently the predicted gas well productivity is more deviated from the actual measurement.In this paper,the characteristics of Qixia Fm reservoirs in this area were firstly analyzed.Then,the method and criterion of the effectiveness evaluation of Qixia Fm reservoirs in the western Sichuan Basin were established by means of numerical simulation and special logging data processing.And the following research results were obtained.First,surface porosity of matrix pores and secondary dissolved vugs calculated based on the special processing of conventional logging and electric imaging logging can be used to evaluate the reservoir properties of reservoirs.Second,deep and shallow dual lateral logging in combination with electric imaging logging and Stoneley wave energy data can be used to evaluate the filtration capacity of reservoirs.Third,the criterion of effective Qixia Fm reservoirs is established,including storage coefficient〓〓0.6,deep lateral resistivity<5000 U$m,surface porosity>0.6%,Stoneley wave attenuation 10% and comprehensive reservoir evaluation index 0.25,and the evaluation criterion can well characterize reservoir quality and gas well productivity.The field application results of this evaluation method and evaluation criterion indicate that the coincidence rate of reservoir effectiveness has increased from 70%to over 90%.Thus,the technical difficulties related to the heterogeneous carbonate reservoir effectiveness evaluation are basically solved.Besides,they provide a basis for the determination of production test layer selection,completion engineering and development scheme so as to cut down the natural gas exploration and development cost.展开更多
This study examines the multi-scale spatio-temporal evolution of drought characteristics in Zhejiang Province.We propose a comprehensive index to identify drought days and events by incorporating three widely used mon...This study examines the multi-scale spatio-temporal evolution of drought characteristics in Zhejiang Province.We propose a comprehensive index to identify drought days and events by incorporating three widely used monitoring indices:the precipitation anomaly percentage,relative humidity index,and standardized precipitation index.The analysis reveals a significant long-term decreasing trend in the frequency of drought days across Zhejiang Province from 1971 to 2020,with a total of 170 drought events being identified.An Empirical Orthogonal Function(EOF)analysis of precipitation anomalies during these events reveals a dominant province-wide monopole mode,alongside a secondary northsouth inverse dipole,a third tripole,and a fourth southwest-northeast inverse dipole.Furthermore,a composite analysis of the drought events demonstrates a widespread increase in temperature across all stations,with a strong spatial correspondence between the temperature anomalies and their associated frequency.The study identifies 21 extreme drought events,characterized by spatially inconsistent precipitation patterns across the entire province.展开更多
To investigate the mechanical response during failure and the impact tendency characteristics of gangue-coal combined structure,uniaxial compression tests were conducted on nine groups of combined structures,each with...To investigate the mechanical response during failure and the impact tendency characteristics of gangue-coal combined structure,uniaxial compression tests were conducted on nine groups of combined structures,each with varying gangue thicknesses and positions.The response patterns of compressive strength,elastic modulus,pre-peak accumulated energy,elastic energy index,and impact energy index were systematically analyzed.Furthermore,a new index for evaluating the impact tendency of gangue-containing coal was proposed,and its effectiveness was verified.The findings are as follows:(1)As the gangue thickness increases,both the compressive strength and the pre-peak energy of the combined structure decrease,whereas the elastic modulus increases accordingly.When the gangue is located in the lower middle position,the combined structure exhibits the lowest compressive strength and elastic modulus but the highest pre peak energy.(2)As the gangue shifts toward the middle position of the combined structure,the failure mode gradually transitions from comple te“crushing”failure to an incomplete“point-type”failure.As gangue thickness further increases,the failure region evolves from overall failure to localized failure,with the degree of failure shifting from complete to incomplete.The K_(crc)value corresponding to“crushing”complete failure is higher and has a stronger impact tendency compared to“point-type”incomplete failure.(3)The proposed comprehensive impact instability evaluation index K_(crc)for the gangue-coal combined structure has shown a significant positive correlation with compressive strength(R_(c))and impact energy index(K_(E)),further verifyi ng its rationality in comprehensively assessing the impact tendency of gangue-containing coal bodies.Applying this index to the evaluation of gangue-containing coal seams provides a more accurate reflection of their impact tendency compared with the residual energy index,which has a wide range of potential applications and practical significance.展开更多
To integrate different renewable energy resources effectively in a microgrid, a configuration optimization model of a multi-energy distributed generation（DG） system and its auxiliary equipment is proposed. The model...To integrate different renewable energy resources effectively in a microgrid, a configuration optimization model of a multi-energy distributed generation（DG） system and its auxiliary equipment is proposed. The model mainly consists of two parts, the determination of initial configuration schemes according to user preference and the selection of the optimal scheme. The comprehensive evaluation index（CEI）, which is acquired through the analytic hierarchy process（AHP） weight calculation method, is adopted as the evaluation criterion to rank the initial schemes. The optimal scheme is obtained according to the ranking results. The proposed model takes the diversity of different equipment parameters and investment cost into consideration and can give relatively suitable and economical suggestions for system configuration.Additionally, unlike Homer Pro, the proposed model considers the complementation of different renewable energy resources, and thus the rationality of the multi-energy DG system is improved compared with the single evaluation criterion method which only considers the total cost.展开更多
[Objective] This study aimed to investigate the dominant populations of late-summer phytoplankton and conduct comprehensive nutritional evaluation of water quality in Bailang Lake. [Method] A series of water quality s...[Objective] This study aimed to investigate the dominant populations of late-summer phytoplankton and conduct comprehensive nutritional evaluation of water quality in Bailang Lake. [Method] A series of water quality survey and phytoplankton sampling was conducted in Bailang Lake in September 2011, a total of four sam- pling points were set, to detect and analyze the total nitrogen, total phosphorus, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and permanganate index in water samples and further conduct comprehensive nutritional evaluation of the water quality factors using comprehensive nutritional state index method. [Result] Water in Bailang Lake was neutral to slightly alkaline with pH of 8.57. The average water trans- parency was 0.4 m, with relatively high content of dissolved oxygen. The content of total nitrogen was relatively high of 3.043 mg/L averagely. Comprehensive nutritional evaluation showed that the water quality of Bailang Lake belonged to moderate eu- trophication. As can be seen from various comprehensive nutritional state indices TLI, the contribution of transparency, chlorophyll a and total nitrogen to the eutrophi- cation in Bailang Lake was the greatest, followed by the permanganate index and total phosphorus. Statistical analysis showed that the average weight-biomass of phy- toplankton in Bailang Lake was 6.442 mg/L, and the average was 146.46x104 individuals/ml. There were eight dominant species in Bailang Lake, including Scenedesmus, Tetraedron, Merismopedia sinica, Phormidium, Merismopedia, Tribonema, Chroomonas and Synedra. [Conclusion] This study provided data informa- tion for the environmental protection and fisheries production in Bailang Lake.展开更多
Development of drought monitoring techniques is important for understanding and mitigating droughts and for rational agricultural management. This study used data from multiple sources, including MOD13 A3, TRMM 3 B43,...Development of drought monitoring techniques is important for understanding and mitigating droughts and for rational agricultural management. This study used data from multiple sources, including MOD13 A3, TRMM 3 B43, and SRTMDEM, for Yunnan Province, China from 2009 to 2018 to calculate the tropical rainfall condition index(TRCI), vegetation condition index(VCI), temperature condition index(TCI), and elevation factors. Principal component analysis(PCA) and analytic hierarchy process(AHP) were used to construct comprehensive drought monitoring models for Yunnan Province. The reliability of the models was verified, following which the drought situation in Yunnan Province for the past ten years was analysed. The results showed that:(1) The comprehensive drought index(CDI) had a high correlation with the standardized precipitation index, standardized precipitation evapotranspiration index, temperature vegetation dryness index, and CLDAS(China Meteorological Administration land data assimilation system), indicating that the CDI was a strong indicator of drought through meteorological, remote sensing and soil moisture monitoring.(2) The droughts from 2009 to 2018 showed generally consistent spatiotemporal changes. Droughts occurred in most parts of the province, with an average drought frequency of 29% and four droughtprone centres.(3) Monthly drought coverage during 2009 to 2014 exceeded that over 2015 to 2018. January had the largest average drought coverage over the study period(61.92%). Droughts at most stations during the remaining months except for October exhibited a weakening trend(slope > 0). The CDI provides a novel approach for drought monitoring in areas with complex terrain such as Yunnan Province.展开更多
Based on the conclusions of domestic and foreign research, we have analyzed the collapse-fall characteristics of overlying strata and the mechanism of aquifer-protective mining in shallow coal seam working faces at th...Based on the conclusions of domestic and foreign research, we have analyzed the collapse-fall characteristics of overlying strata and the mechanism of aquifer-protective mining in shallow coal seam working faces at the Shendong Mine. We have selected the height of the water-conducting fracture zone in overlying strata as a composite index and established the applicable conditions of aquifer-protective mining in shallow coal seams with a multi-factor synthetic-index classification method. From our calculations and analyses of variance, we used factors such as the overlying strata strength, mining disturbing factors and rock integrity as related factors of the composite index. We have classified the applicable conditions of aquifer-protective mining in shallow coal seams into seven types by comparing the result of the height of water-conducting fractured zones of long-wall and short-wall working faces with the thickness of the bedrock, the thickness of the weathered zone and the size of safety coal-rock pillars. As a result, we propose the preliminary classification system of aquifer-protective mining in shallow coal seams. It can provide a theoretical guidance for safe applications of aquifer-protective mining technology in shallow coal seams under similar conditions.展开更多
文摘Equipment management is one of the important parts of business administra- tion of coal. Most of coal mines take no account of their equipment management, and have no comprehensive and effective evaluation index system. Based on the analysis of the equipment evaluation measures of reform and the applications, the paper built up a comprehensive and effective evaluation index system of coal mine equipment, and im- proved the evaluation method with the use of fuzzy theory, analytic hierarchy process and entropy method.
基金the Science and Technology Project of Global Energy Interconnection Group Co.,Ltd.(No.524500180014).
文摘With the global economy integration and progress in energy transformation,it has become a general trend to surpass national boundaries to achieve wider and optimal energy resource allocations.Consequently,there is a critical n eed to adopt scie ntific approaches in assessi ng cross-border power grid interconnection projects.First,con sidering the promotion of large-scale renewable energy resources and improvements in system adequacy,a comprehensive assessment index system,including costs,socio-economic benefits,environmental benefits,and technical benefits,is established in this study.Second,a synthetic assessment framework is proposed for cross-border power grid interconnection projects based on the index system comprising cost-benefit analysis,with market and network simulations,iterative methods for indicator weight evaluation,and technique for order preferenee by similarity to an ideal solution(TOPSIS)method for the project rankings.Fin ally,by assessi ng and comparing three cross-border projects betwee n Europe and Asia,the proposed index system and assessment framework have been proved to be effective and feasible;the results of this system can thus support investment decision-making related to such projects in the future.
文摘To better reduce the carbon emissions of a park-integrated energy system(PIES),optimize the comprehensive operating cost,and smooth the load curve,a source-load flexible response model based on the comprehensive evaluation index is proposed.Firstly,a source-load flexible response model is proposed under the stepped carbon trading mechanism;the organic Rankine cycle is introduced into the source-side to construct a flexible response model with traditional combined heat and power(CHP)unit and electric boiler to realize the flexible response of CHP to load;and the load-side categorizes loads into transferable,interruptible,and substitutable loads according to the load characteristics and establishes a comprehensive demand response model.Secondly,the analytic network process(ANP)considers the linkages between indicators and allows decision-makers to consider the interactions of elements in a complex dynamic system,resulting in more realistic indicator assignment values.Considering the economy,energy efficiency,and environment,the PIES optimization operation model based on the ANP comprehensive evaluation index is constructed to optimize the system operation comprehensively.Finally,the CPLEX solver inMATLABwas employed to solve the problem.The results of the example showthat the source-load flexible response model proposed in this paper reduces the operating cost of the system by 29.90%,improves the comprehensive utilization rate by 15.00%,and reduces the carbon emission by 26.98%,which effectively enhances the system’s economy and low carbon,and the comprehensive evaluation index based on the ANP reaches 0.95,which takes into account the economy,energy efficiency,and the environment,and is more superior than the single evaluation index.
基金supported by the National Key Research and Development Program of China under the theme“Construction of a data representation framework for sustainable development indicators”[Grant No.2022YFC3802903-01]the National Natural Science Foundation of China“An economic theory based on the new production function in carbon neutrality”[Grant No.72250064]the National Natural Science Foundation of China“Macroeconomics”[Grant No.72122011].
文摘Climate change severely challenges our ecosystem and society,affecting urban residents’socioeconomic activities.Thus,assessing severe weather risk is crucial for evaluating urban sustainability;understanding trends,causes,and impacts on socioeconomic development;and supporting the United Nations Sustainable Development Goal(SDG)13.Using meteorological data from 1980 to 2020,we investigate five disaster-causing severe weather events in China and construct a comprehensive index of extreme climate risk(CIECR)at the county,city,province,and national levels.The CIECR can identify high-risk regions and primary severe weather events and provide early warnings.We empirically test the impact of extreme climate risks on agricultural production,industrial structure,and labor employment.The results show high risks in Xinjiang,northern Inner Mongolia,and southern regions,with high temperatures,low temperatures,and high winds as the leading risks.At the national level,the extreme climate risk fluctuates,indicating climate warming.While risks reduce agricultural production and employment,they promote modern agriculture,industrial production,and urbanization.The novelty of the study lies in its development of the county-level CIECR,which can capture heterogeneity characteristics and provide microdata support for urban climate change research and efforts toward SDG 13.This study aids in mitigating climate risks;responding to climate change;and comprehensively analyzing the causes,trends,and impacts of extreme climate risks.
文摘Background:Accurate complication reporting in endourology remains challenging,with the Clavien-Dindo Classification and Comprehensive Complication Index being the most commonly used systems.This study aimed to compare surgical outcomes and complication reporting in ureterolithotripsy(URL),percutaneous nephrolithotomy(PCNL),and extracorporeal shock wave lithotripsy(ESWL)using both systems.Methods:This prospective,single-center,non-interventional study included 473 patients undergoing URL,PCNL,or ESWL from October 2022 to October 2024.Demographic,stone-related,and procedural variables were recorded.Complications were classified using the CDC,and cumulative morbidity was assessed using CCI.Statistical analyses,including univariate and multivariate regression,were performed to identify predictors of higher CCI scores.Results:PCNL was associated with the highest complication rates,including an 11%transfusion rate.ESWL had the lowest complication burden,while URL demonstrated intermediate risk.CCI scores correlated positively with length of stay(LOS;r=0.47),highlighting its ability to capture overall morbidity.Multivariate analysis identified stone size,operating time,and positive urine culture as significant predictors of higher CCI scores.The CCI provided a more comprehensive representation of morbidity compared to the CDC.Conclusions:CCI demonstrates superior sensitivity in evaluating postoperative morbidity compared to CDC,particularly in more invasive procedures such as PCNL.Standardized reporting frameworks incorporating CCI may enhance surgical outcome assessment in endourology.
文摘BACKGROUND Detailed data on the relation of post-operative complications with clinical outcomes after simultaneous pancreas-kidney(SPK)transplantation is lacking.AIM To compare Clavien-Dindo classification(CDC)and comprehensive complication index(CCI)in predicting outcomes after SPK.METHODS Data for patients undergoing SPK between 1999-2019 were analyzed.Information on recipients’baseline characteristics,peri-operative management and postoperative complications were collated.Length of hospital stay(LOS)was the primary study outcome,and the associations with CDC and CCI were evaluated using Spearman’s(ρ)correlation coefficients.RESULTS In the study period,data were available for 128 patients(female n=44,34.4%).Sixty-nine patients had at least one complication with the highest CDC grade of I,II,III,and IV in 8(6.3%),22(17.2%),32(25%),and 7(5.5%)patients,respectively. The mean LOS was 21.4 ± 17.7 days. Both classification systems were correlated with LOS, yet CCI was stronger(Spearman’s ρ: 0.694 vs 0.602, P < 0.001). Female patients (P = 0.019) and patients with pre-transplant cardiovascularevents (P = 0.02) had longer LOS. After adjusted multivariable analysis, the link between LOS and both theCDC and CCI remained relevant. CCI had a superior fit compared to CDC (r2 = 0.729 vs r2 = 0.481), with every 10CCI points being associated with a 5.27 day (P < 0.001) increased LOS.CONCLUSIONThis study showed that the CCI was better linked with LOS compared to CDC and might represent a useful scoreto evaluate the overall burden of postoperative complications in patients undergoing SPK.
基金supported by the National Natural Science Foundation of China(42377072,52409105).
文摘Water quality is a pressing issue affecting the sustainable development of lakes.To elucidate the spatial and temporal characteristics of water quality in Bos ten Lake,China,this study constructed a comprehensive water quality index(CWQI) based on key water quality indicators,utilizing water quality data collected from 17 sampling sites spaning from 2011 to 2019.Key water quality indicators were determined using factor analysis,and the spatial and temporal characteristics of key water quality indicators and the CWQI were examined using multivariate statistical analysis.The key water quality indicators included pH,chemical oxygen demand(COD),water transparency(SD),NO3-,total dissolved solids(TDS),Cl-,SO42-,and electrical conductivity(EC).Furthermore,the contribution rates of all water quality indicators to the water quality were quantitatively elucidated using the SHapley Additive explanations(SHAP) values,thereby validating the factor analysis outcomes.Among the eight key water quality indicators,the COD had the most significant influence on the water quality of Bos ten Lake.The water quality condition of Bosten Lake has remained at Class Ⅲ from 2011 to 2019(CWQI ranging from3.19 to 3.90).The water quality of Bos ten Lake was characterized by distinct regional differences that arose from hydrodynamic processes within the lake and upstream water quality.The southwestern region exhibited the best water quality(mean CWQI of 3.47),whereas the northwestern region exhibited the worst(mean CWQI of 3.58).It is crucial to acknowledge that alongside the increase in industrial and agricultural effluent discharge monitoring,a series of ecological restoration projects for the lake basin have been initiated.Over time,the water quality of Bosten Lake showed gradual improvement(improvement rate of CWQI at 0.05/a).This study provides a critical scientific basis for enhancing the understanding and effective management of water quality in the Bosten Lake Basin through a comprehensive analysis of its spatial and temporal evolution and driving mechanisms.
文摘The purpose of establishing a comprehensive evaluation index system of agricultural information service in rural areas is mainly to evaluate the level of agricultural information service reasonably, comprehensively and scientifically. In establishing the comprehensive evaluation index system of agricultural information service, some principles should be followed, i.e. operability, independence, safety and universality. At present, when constructing the comprehensive evaluation index system of agricultural information service, the comprehensive evaluation is mainly carried out around the basic service facilities of agricultural information, the internal and external environment during the construction of agricultural information, the data of agricultural information construction and the work of agricultural information construction, so as to ensure that the comprehensive evaluation index system of agricultural information service is practical, reasonable, comprehensive and scientific.
基金supported by the National Natural Science Foundation of China(No.41807386)Tianjin Financial Budget Project of 2018。
文摘The Yongding New River is essential for the water supplies of Tianjin.To date,there is no comprehensive report that assesses the year-round water quality of the Yongding New River Main stream.Moreover,little attention has been given to determining a combined weight for improving the traditional comprehensive water quality identification index(ICWQII)by the game theory.Seven water quality parameters were investigated monthly along the main stream of the Yongding New River from May 2018 to April 2019.Organic contaminants and nitrogen pollution were mainly caused by point sources pollution,and the total phosphorus mainly by non-point source pollution.Dramatic spatio-temporal variations of water quality parameters were jointly caused by different pollutant sources and hydrometeorological factors.In terms of this study,an improved comprehensive water quality identification index(ICWQII)based on entropy weight or variation coefficient and traditional CWQII underestimated the water qualities,and an ICWQII based on the superstandard multiple method overvalued the assessments.By contrast,water qualities assessments done with an ICWQII based on the game theory matched perfectly with the practical situation.The ICWQII based on game theory proposed in this study takes into account not only the degree of disorder and variation of water quality data,but also the influence of standard-exceeded pollution indicators,whose results are relatively reasonable.All findings and the ICWQII based on game theory can provide scientific support for decisions related to the water environment management of the Yongding New River and other waters.
基金Sponsored by National Natural Science Foundation of China(41271060)
文摘Based on the ETM remote sensing images of Guangzhou City in 2014, the spatial distribution results o f three environmental factors including vegetation coverage(NDVI), soil index(vegetation index of bare soil) and sl ope were obtained. By using comprehensive index method, the normalized environmental factors were weighted and superimposed, and the fi nal evaluation results of ecological environment in Guangzhou City were obtained. The results showed that overall situation of natural ecological environment in Guangzhou was not optimistic, that is, the area of land with bad, moderate, good and superior environment accounted for 59.70%, 35.79%, 4.50% and around 0.01% of total area of land in Guangzhou City respectively. Ecological environment was generally poor in the central urban districts in the south of Guangzhou City, while it was relatively better in the north and northeast. Attaching importance to the constr uction of greenbelts and greenways is an effective way to improve regional environmental quality and natural ecological e nvironment level.
基金This study was funded by the National Key R&D Program of China(2021YFD1900700)the National Natural Science Foundation of China(51909221)the China Postdoctoral Science Foundation(2020T130541 and 2019M650277).
文摘In order to further improve the utility of unmanned aerial vehicle(UAV)remote-sensing for quickly and accurately monitoring the growth of winter wheat under film mulching, this study examined the treatments of ridge mulching,ridge–furrow full mulching, and flat cropping full mulching in winter wheat.Based on the fuzzy comprehensive evaluation (FCE) method, four agronomic parameters (leaf area index, above-ground biomass, plant height, and leaf chlorophyll content) were used to calculate the comprehensive growth evaluation index (CGEI) of the winter wheat, and 14 visible and near-infrared spectral indices were calculated using spectral purification technology to process the remote-sensing image data of winter wheat obtained by multispectral UAV.Four machine learning algorithms, partial least squares, support vector machines, random forests, and artificial neural network networks(ANN), were used to build the winter wheat growth monitoring model under film mulching, and accuracy evaluation and mapping of the spatial and temporal distribution of winter wheat growth status were carried out.The results showed that the CGEI of winter wheat under film mulching constructed using the FCE method could objectively and comprehensively evaluate the crop growth status.The accuracy of remote-sensing inversion of the CGEI based on the ANN model was higher than for the individual agronomic parameters, with a coefficient of determination of 0.75,a root mean square error of 8.40, and a mean absolute value error of 6.53.Spectral purification could eliminate the interference of background effects caused by mulching and soil, effectively improving the accuracy of the remotesensing inversion of winter wheat under film mulching, with the best inversion effect achieved on the ridge–furrow full mulching area after spectral purification.The results of this study provide a theoretical reference for the use of UAV remote-sensing to monitor the growth status of winter wheat with film mulching.
基金National Natural Science Foundation(Project Number:41101080)Natural Science Foundation of Shandong Province(Project Number:ZR2014DQ028/ZR2015DM004)
文摘Wetland park is an important mode of wetland protection, meanwhile, construction of comprehensive index system has become the hotspot and keystone of the researches on Wetland Parks. Basing on different development stages, this paper firstly divided the Wetland Parks into three categories, including the start-up stage, the development stage and the refinement stage. And then screened and identified the direction and keypoints of comprehensive evaluation for wetland parks in different development stages using expert scoring, questionnaire and analytic hierarchy process(AHP).
基金support of the National Natural Science Foundation of China(Grant No.52074332).
文摘Natural gas hydrates(hereinafter referred to as hydrates)are a promising clean energy source.However,their current development is far from reaching commercial exploitation.Reservoir stimulation tech-nology provides new approaches to enhance hydrate development effectiveness.Addressing the current lack of quantitative and objective methods for evaluating the fracability of hydrate reservoirs,this study clarifies the relationship between geological and engineering fracability and proposes a comprehensive evaluation model for hydrate reservoir fracability based on grey relational analysis and the criteria importance through intercriteria correlation method.By integrating results from hydraulic fracturing experiments on hydrate sediments,the fracability of hydrate reservoirs is assessed.The concept of critical construction parameter curves for hydrate reservoirs is introduced for the first time.Additionally,two-dimensional fracability index evaluation charts and three-dimensional fracability construction condition discrimination charts are established.The results indicate that as the comprehensive fracability index increases,the feasibility of forming fractures in hydrate reservoirs improves,and the required normalized fracturing construction parameters gradually decrease.The accuracy rate of the charts in judging experimental results reached 89.74%,enabling quick evaluations of whether hydrate reservoirs are worth fracturing,easy to fracture,and capable of being fractured.This has significant engineering implications forthehydraulicfracturingof hydratereservoirs.
基金supported by the Scientific Research Project of PetroChina Southwest Oil and Gasfield Company“Study of Well Logging Evaluation Method for Permian Reservoirs in West Sichuan Region”(No.:XNS05JS2016-46).
文摘In the western Sichuan Basin,the Permian Qixia Fm grained dolomite reservoirs are currently the new focus of natural gas exploration and development.The Qixia Fm is characterized by developed dissolved vugs and fractures,low matrix porosity and strong heterogeneity,so evaluation faults tend to occur if reservoir effectiveness is evaluated by means of the traditional porosity evaluation,and the consequently the predicted gas well productivity is more deviated from the actual measurement.In this paper,the characteristics of Qixia Fm reservoirs in this area were firstly analyzed.Then,the method and criterion of the effectiveness evaluation of Qixia Fm reservoirs in the western Sichuan Basin were established by means of numerical simulation and special logging data processing.And the following research results were obtained.First,surface porosity of matrix pores and secondary dissolved vugs calculated based on the special processing of conventional logging and electric imaging logging can be used to evaluate the reservoir properties of reservoirs.Second,deep and shallow dual lateral logging in combination with electric imaging logging and Stoneley wave energy data can be used to evaluate the filtration capacity of reservoirs.Third,the criterion of effective Qixia Fm reservoirs is established,including storage coefficient〓〓0.6,deep lateral resistivity<5000 U$m,surface porosity>0.6%,Stoneley wave attenuation 10% and comprehensive reservoir evaluation index 0.25,and the evaluation criterion can well characterize reservoir quality and gas well productivity.The field application results of this evaluation method and evaluation criterion indicate that the coincidence rate of reservoir effectiveness has increased from 70%to over 90%.Thus,the technical difficulties related to the heterogeneous carbonate reservoir effectiveness evaluation are basically solved.Besides,they provide a basis for the determination of production test layer selection,completion engineering and development scheme so as to cut down the natural gas exploration and development cost.
基金Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(LZJMD24D050002)Natural Science Foundation of Zhejiang Province(LZJMZ23D050001,LGF22D050007,LGF19D050001)Zhejiang Province Meteor-ological Science Foundation(2022ZD07)。
文摘This study examines the multi-scale spatio-temporal evolution of drought characteristics in Zhejiang Province.We propose a comprehensive index to identify drought days and events by incorporating three widely used monitoring indices:the precipitation anomaly percentage,relative humidity index,and standardized precipitation index.The analysis reveals a significant long-term decreasing trend in the frequency of drought days across Zhejiang Province from 1971 to 2020,with a total of 170 drought events being identified.An Empirical Orthogonal Function(EOF)analysis of precipitation anomalies during these events reveals a dominant province-wide monopole mode,alongside a secondary northsouth inverse dipole,a third tripole,and a fourth southwest-northeast inverse dipole.Furthermore,a composite analysis of the drought events demonstrates a widespread increase in temperature across all stations,with a strong spatial correspondence between the temperature anomalies and their associated frequency.The study identifies 21 extreme drought events,characterized by spatially inconsistent precipitation patterns across the entire province.
基金Project(52274130)supported by the National Natural Science Foundation of ChinaProject(ZR2024ZD22)supported by the Major Basic Research Project of the Shandong Provincial Natural Science Foundation,China+1 种基金Project(2023375)supported by the Guizhou University Research and Innovation Team,ChinaProject(LH[2024]-026)supported by the Guizhou Science and Technology Plan Project,China。
文摘To investigate the mechanical response during failure and the impact tendency characteristics of gangue-coal combined structure,uniaxial compression tests were conducted on nine groups of combined structures,each with varying gangue thicknesses and positions.The response patterns of compressive strength,elastic modulus,pre-peak accumulated energy,elastic energy index,and impact energy index were systematically analyzed.Furthermore,a new index for evaluating the impact tendency of gangue-containing coal was proposed,and its effectiveness was verified.The findings are as follows:(1)As the gangue thickness increases,both the compressive strength and the pre-peak energy of the combined structure decrease,whereas the elastic modulus increases accordingly.When the gangue is located in the lower middle position,the combined structure exhibits the lowest compressive strength and elastic modulus but the highest pre peak energy.(2)As the gangue shifts toward the middle position of the combined structure,the failure mode gradually transitions from comple te“crushing”failure to an incomplete“point-type”failure.As gangue thickness further increases,the failure region evolves from overall failure to localized failure,with the degree of failure shifting from complete to incomplete.The K_(crc)value corresponding to“crushing”complete failure is higher and has a stronger impact tendency compared to“point-type”incomplete failure.(3)The proposed comprehensive impact instability evaluation index K_(crc)for the gangue-coal combined structure has shown a significant positive correlation with compressive strength(R_(c))and impact energy index(K_(E)),further verifyi ng its rationality in comprehensively assessing the impact tendency of gangue-containing coal bodies.Applying this index to the evaluation of gangue-containing coal seams provides a more accurate reflection of their impact tendency compared with the residual energy index,which has a wide range of potential applications and practical significance.
基金The National Natural Science Foundation of China(No.51377021)the Science and Technology Project of State Grid Corporation of China(No.SGTJDK00DWJS1600014)
文摘To integrate different renewable energy resources effectively in a microgrid, a configuration optimization model of a multi-energy distributed generation（DG） system and its auxiliary equipment is proposed. The model mainly consists of two parts, the determination of initial configuration schemes according to user preference and the selection of the optimal scheme. The comprehensive evaluation index（CEI）, which is acquired through the analytic hierarchy process（AHP） weight calculation method, is adopted as the evaluation criterion to rank the initial schemes. The optimal scheme is obtained according to the ranking results. The proposed model takes the diversity of different equipment parameters and investment cost into consideration and can give relatively suitable and economical suggestions for system configuration.Additionally, unlike Homer Pro, the proposed model considers the complementation of different renewable energy resources, and thus the rationality of the multi-energy DG system is improved compared with the single evaluation criterion method which only considers the total cost.
基金Supported by Science and Technology Project in Anhui Province(11070303016)~~
文摘[Objective] This study aimed to investigate the dominant populations of late-summer phytoplankton and conduct comprehensive nutritional evaluation of water quality in Bailang Lake. [Method] A series of water quality survey and phytoplankton sampling was conducted in Bailang Lake in September 2011, a total of four sam- pling points were set, to detect and analyze the total nitrogen, total phosphorus, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and permanganate index in water samples and further conduct comprehensive nutritional evaluation of the water quality factors using comprehensive nutritional state index method. [Result] Water in Bailang Lake was neutral to slightly alkaline with pH of 8.57. The average water trans- parency was 0.4 m, with relatively high content of dissolved oxygen. The content of total nitrogen was relatively high of 3.043 mg/L averagely. Comprehensive nutritional evaluation showed that the water quality of Bailang Lake belonged to moderate eu- trophication. As can be seen from various comprehensive nutritional state indices TLI, the contribution of transparency, chlorophyll a and total nitrogen to the eutrophi- cation in Bailang Lake was the greatest, followed by the permanganate index and total phosphorus. Statistical analysis showed that the average weight-biomass of phy- toplankton in Bailang Lake was 6.442 mg/L, and the average was 146.46x104 individuals/ml. There were eight dominant species in Bailang Lake, including Scenedesmus, Tetraedron, Merismopedia sinica, Phormidium, Merismopedia, Tribonema, Chroomonas and Synedra. [Conclusion] This study provided data informa- tion for the environmental protection and fisheries production in Bailang Lake.
基金This research was funded by the Multigovernment International Science and Technology Innovation Cooperation Key Project of the National Key Research and Development Program of China(Grant No.2018YFE0184300)Erasmus+Capacity Building in Higher Education of the Education,Audiovisual and Culture Executive Agency(EACEA)(Grant No.586037-EPP-1-2017-1-HU-EPPKA2CBHE-JP)+3 种基金the National Natural Science Foundation of China(Grant No.41561048)the Technical Methods and Empirical Study on Ecological Assets Measurement in County Level of Yunnan Province(Grant No.ZDZZD201506)the Young and Middleaged Academic and Technical Leaders Reserve Talents Training Program of Yunnan Province(Grant No.2008PY056)the Program for Innovative Research Team(in Science and Technology)at the University of Yunnan Province,IRTSTYN。
文摘Development of drought monitoring techniques is important for understanding and mitigating droughts and for rational agricultural management. This study used data from multiple sources, including MOD13 A3, TRMM 3 B43, and SRTMDEM, for Yunnan Province, China from 2009 to 2018 to calculate the tropical rainfall condition index(TRCI), vegetation condition index(VCI), temperature condition index(TCI), and elevation factors. Principal component analysis(PCA) and analytic hierarchy process(AHP) were used to construct comprehensive drought monitoring models for Yunnan Province. The reliability of the models was verified, following which the drought situation in Yunnan Province for the past ten years was analysed. The results showed that:(1) The comprehensive drought index(CDI) had a high correlation with the standardized precipitation index, standardized precipitation evapotranspiration index, temperature vegetation dryness index, and CLDAS(China Meteorological Administration land data assimilation system), indicating that the CDI was a strong indicator of drought through meteorological, remote sensing and soil moisture monitoring.(2) The droughts from 2009 to 2018 showed generally consistent spatiotemporal changes. Droughts occurred in most parts of the province, with an average drought frequency of 29% and four droughtprone centres.(3) Monthly drought coverage during 2009 to 2014 exceeded that over 2015 to 2018. January had the largest average drought coverage over the study period(61.92%). Droughts at most stations during the remaining months except for October exhibited a weakening trend(slope > 0). The CDI provides a novel approach for drought monitoring in areas with complex terrain such as Yunnan Province.
基金Financial support for this work, provided by the research fund of the North China Institute of Science and Technology (No.A09002)the National Natural Science Foundation of China (No.50834005)the National Basic Research Program of China (No.2007CB209402)
文摘Based on the conclusions of domestic and foreign research, we have analyzed the collapse-fall characteristics of overlying strata and the mechanism of aquifer-protective mining in shallow coal seam working faces at the Shendong Mine. We have selected the height of the water-conducting fracture zone in overlying strata as a composite index and established the applicable conditions of aquifer-protective mining in shallow coal seams with a multi-factor synthetic-index classification method. From our calculations and analyses of variance, we used factors such as the overlying strata strength, mining disturbing factors and rock integrity as related factors of the composite index. We have classified the applicable conditions of aquifer-protective mining in shallow coal seams into seven types by comparing the result of the height of water-conducting fractured zones of long-wall and short-wall working faces with the thickness of the bedrock, the thickness of the weathered zone and the size of safety coal-rock pillars. As a result, we propose the preliminary classification system of aquifer-protective mining in shallow coal seams. It can provide a theoretical guidance for safe applications of aquifer-protective mining technology in shallow coal seams under similar conditions.
