期刊文献+
共找到300,946篇文章
< 1 2 250 >
每页显示 20 50 100
‘Partly'globalized networks and driving mechanism in resource-based state-owned enterprises:A case study of J Group 被引量:1
1
作者 Jing Xu Yongchun Yang +1 位作者 Yongjiao Zhang Shan Man 《Geography and Sustainability》 CSCD 2024年第1期77-88,共12页
In the context of economic globalization,while multinational enterprises from developed countries occupy a high-end position in the global value chain,enterprises from developing countries are often marginalized in th... In the context of economic globalization,while multinational enterprises from developed countries occupy a high-end position in the global value chain,enterprises from developing countries are often marginalized in the world market.In China,resource-based state-owned enterprises(SOEs)are tasked with the mission of safeguarding resource security,and their internationalization development ideas and strategic deployment are significantly and fundamentally different from those of other non-state-owned enterprises and large multinational corporations.This study provides ideas for the globalization policies of enterprises in developing countries.We consider J Group in western China as a case and discuss its productive investment and global production network development from 2010 to 2019.We found that J Group was‘Partly'globalized,and there are multiple core nodes with the characteristics of centralized and decentralized coexistence in the production network;in addition,the overall layout centre shifted to Southeast Asia and China;however,its global production was restricted by the enterprise's investment security considerations,support and restrictions of the home country,political security risk of the host country,and sanctions from the West.These findings provide insights for future research:under the wave of anti-globalization and'internal circulation as the main body',resource SOEs should consider the potential risk of investment,especially keeping the middle and downstream industrial chain in China as much as possible. 展开更多
关键词 Global production networks Global value chain Productive investment Resource SOEs J Group ‘Partly'globalized
下载PDF
Labor compensation,labor productivity and labor cost advantage—An empirical study of Chinese manufacturing enterprises during 2000-2007
2
作者 都阳 曲玥 《China Economist》 2009年第5期58-65,共8页
Unlike the usual practice of equating wages or labor compensation with labor cost,this paper incorporates labor productivity into an analytical framework and holds that the labor cost advantage is the relative relatio... Unlike the usual practice of equating wages or labor compensation with labor cost,this paper incorporates labor productivity into an analytical framework and holds that the labor cost advantage is the relative relationship between labor compensation and labor productivity.Based on an empirical study of the data of Chinese manufacturing firms that include all state-owned enterprises and non-state-owned enterprises with their annual revenue greater than 5 million yuan from 2000 to 2007,this paper finds that labor compensation growth was accompanied by faster labor productivity growth.Hence,the labor cost advantage was not weakened during this period.Furthermore,this paper conducts an exploration of how to sustain labor cost advantages in the future and proposes that they can be sustained by upgrading the industrial structure and improving the education system. 展开更多
关键词 LABOR COMPENSATION LABOR productivity LABOR COST ADVANTAGE
下载PDF
The Impact of the Establishment of National High-tech Zones on Total Factor Productivity of Chinese Enterprises
3
作者 Wang Mingyi Liu Xiaoyu 《China Economist》 2023年第3期68-93,共26页
The National High-tech Zone(NHTZs)is an important strategic platform for cultivating high-tech industries and realizing high-quality economic development in China.Based on the combined data from 2006 to 2014 of the in... The National High-tech Zone(NHTZs)is an important strategic platform for cultivating high-tech industries and realizing high-quality economic development in China.Based on the combined data from 2006 to 2014 of the industrial enterprise database,the customs database,and the China Development Zones Audit and Announcement Catalogue(abbreviated asthe Catalogue),this paper systematically investigates the influence of the construction of NHTZs on enterprise’s total factor productivity(TFP).Results show that NHTZs have a positive impact on the TFP of enterprises in the zone,and this conclusion is still valid after considering endogeneity problems.Furthermore,the above productivity effects of NHTZs are heterogeneous in terms of enterprise ownership,external environment and establishment time,and NHTZs have greater stimulation effects on enterprise productivity after comparing with other types of functional zones.An investigation of the specific mechanisms at play shows that NHTZs promote the TFP of enterprises in the zone through the release of preferential policies,strengthening the“technology spillover effects”of imported intermediate goods,enhancing enterprise’s innovation ability and attracting talent.In addition,based on the decomposition of industry productivity,this paper also investigates the impact of NHTZs on changes in industry productivity and finds that NHTZs promote the overall productivity of specific industries mainly by stimulating the productivity improvement of incumbent enterprises and expanding the market share of high-productivity enterprises.Moreover,the preferential policies of NHTZs do not significantly stimulate high-productivity enterprises to enter the zones,nor do they cause low-productivity enterprises to exit.This research is helpful in objectively evaluating the economic effects of the NHTZs in China and in providing a theoretical basis for its further adjustment. 展开更多
关键词 National High-tech Zones(NHTZs) total factor productivity(TFP) DIFFERENCE-IN-DIFFERENCES changes in industry productivity
下载PDF
Simulation of the Ecosystem Productivity Responses to Aerosol Diffuse Radiation Fertilization Effects over the Pan-Arctic during 2001–19 被引量:1
4
作者 Zhiding ZHANG Xu YUE +3 位作者 Hao ZHOU Jun ZHU Yadong LEI Chenguang TIAN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第1期84-96,共13页
The pan-Arctic is confronted with air pollution transported from lower latitudes.Observations have shown that aerosols help increase plant photosynthesis through the diffuse radiation fertilization effects(DRFEs).Whil... The pan-Arctic is confronted with air pollution transported from lower latitudes.Observations have shown that aerosols help increase plant photosynthesis through the diffuse radiation fertilization effects(DRFEs).While such DRFEs have been explored at low to middle latitudes,the aerosol impacts on pan-Arctic ecosystems and the contributions by anthropogenic and natural emission sources remain less quantified.Here,we perform regional simulations at 0.2o×0.2ousing a well-validated vegetation model(Yale Interactive terrestrial Biosphere,YIBs)in combination with multi-source of observations to quantify the impacts of aerosol DRFEs on the net primary productivity(NPP)in the pan-Arctic during 2001-19.Results show that aerosol DRFEs increase pan-Arctic NPP by 2.19 Pg C(12.8%)yr^(-1)under clear-sky conditions,in which natural and anthropogenic sources contribute to 8.9% and 3.9%,respectively.Under all-sky conditions,such DRFEs are largely dampened by cloud to only 0.26 Pg C(1.24%)yr^(-1),with contributions of 0.65% by natural and 0.59% by anthropogenic species.Natural aerosols cause a positive NPP trend of 0.022% yr^(-1)following the increased fire activities in the pan-Arctic.In contrast,anthropogenic aerosols induce a negative trend of-0.01% yr^(-1)due to reduced emissions from the middle latitudes.Such trends in aerosol DRFEs show a turning point in the year of 2007 with more positive NPP trends by natural aerosols but negative NPP trends by anthropogenic aerosols thereafter.Though affected by modeling uncertainties,this study suggests a likely increasing impact of aerosols on terrestrial ecosystems in the pan-Arctic under global warming. 展开更多
关键词 diffuse radiation fertilization effects anthropogenic aerosols natural aerosols pan-Arctic net primary productivity
下载PDF
Exogenous Financing,State-Ownership Features and Enterprises Productivity-An Empirical Analysis on Listed Chinese Manufacturing Enterprises
5
作者 Xiangqi Zhou Jiawen Qi Haiyue Liu 《Chinese Business Review》 2018年第9期431-441,共11页
This study examines how the exogenous financing and state-ownership features affect the enterprises’productivity by observing the financing data of 1,481 Chinese listed enterprises over the period 2001-2016.The resul... This study examines how the exogenous financing and state-ownership features affect the enterprises’productivity by observing the financing data of 1,481 Chinese listed enterprises over the period 2001-2016.The result shows that long-term loan has a positive impact on enterprises’productivity.Short-term loan and account payable have a negative impact on enterprises’productivity.Also,we find that state-ownership features have a negative impact on enterprises productivity.Moreover,this paper investigates the relationship between enterprises’productivity and the degree of regional economic development measured by GDP on provincial level.The result shows provincial economic development is positively related to the enterprises productivity.These findings are useful for both related authorities and enterprises for better understanding of the financial channels and constrains in China and the possible solutions to more diversified exogenous financing. 展开更多
关键词 EXOGENOUS FINANCING state-ownership FEATURES enterprises productivity
下载PDF
Research on Improving Labor Productivity in Chinese Railway Enterprises
6
作者 Qun Li Xiangyu Zhao Ting Fang Pingyan Wan Rui Zhang 《Chinese Business Review》 2004年第9期1-6,共6页
Our research aims to summarize the implementation results of the former strategy of reducing redundant personnel and improving productivity in Chinese railway system. Based on the experience and advanced methods of fo... Our research aims to summarize the implementation results of the former strategy of reducing redundant personnel and improving productivity in Chinese railway system. Based on the experience and advanced methods of foreign railway enterprises, the thesis studies the way and measures for the Chinese railway enterprises to improve the labor productivity in the new historical period and provides policy suggestions for further improving labor productivity in Chinese railway enterprises. 展开更多
关键词 Chinese railway transportation enterprises labor productivity RESEARCH
下载PDF
Research Progress and Prospects of Total Factor Productivity in the Construction Industry 被引量:1
7
作者 Chen WANG Shijie YU +2 位作者 Chenhao LIANG Lidan CAI Xiaohong XIONG 《Asian Agricultural Research》 2024年第7期39-41,共3页
The high-quality development of the construction industry fundamentally stems from the significant improvement of total factor productivity.Therefore,it is of crucial significance for promoting the development of the ... The high-quality development of the construction industry fundamentally stems from the significant improvement of total factor productivity.Therefore,it is of crucial significance for promoting the development of the construction industry to a higher level by scientifically and accurately measuring the total factor productivity of the construction industry and deeply analyzing the influencing factors behind it.Based on a comprehensive consideration of research methods and influencing factors,this paper systematically reviews the existing relevant literature on total factor productivity in the construction industry,aiming to reveal the current research development trend in this field and point out potential problems.This effort aims to provide a solid theoretical foundation and valuable reference for further in-depth research,and jointly promote the continuous progress and development of total factor productivity research in the construction industry. 展开更多
关键词 Construction industry Total factor productivity Research progress Influence factor Theoretical basis
下载PDF
Spatiotemporal changes of gross primary productivity and its response to drought in the Mongolian Plateau under climate change 被引量:1
8
作者 ZHAO Xuqin LUO Min +3 位作者 MENG Fanhao SA Chula BAO Shanhu BAO Yuhai 《Journal of Arid Land》 SCIE CSCD 2024年第1期46-70,共25页
Gross primary productivity(GPP)of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought.Understanding the impact of droughts on different types of vegetation... Gross primary productivity(GPP)of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought.Understanding the impact of droughts on different types of vegetation GPP provides insight into the spatiotemporal variation of terrestrial carbon sinks,aiding efforts to mitigate the detrimental effects of climate change.In this study,we utilized the precipitation and temperature data from the Climatic Research Unit,the standardized precipitation evapotranspiration index(SPEI),the standardized precipitation index(SPI),and the simulated vegetation GPP using the eddy covariance-light use efficiency(EC-LUE)model to analyze the spatiotemporal change of GPP and its response to different drought indices in the Mongolian Plateau during 1982-2018.The main findings indicated that vegetation GPP decreased in 50.53% of the plateau,mainly in its northern and northeastern parts,while it increased in the remaining 49.47%area.Specifically,meadow steppe(78.92%)and deciduous forest(79.46%)witnessed a significant decrease in vegetation GPP,while alpine steppe(75.08%),cropland(76.27%),and sandy vegetation(87.88%)recovered well.Warming aridification areas accounted for 71.39% of the affected areas,while 28.53% of the areas underwent severe aridification,mainly located in the south and central regions.Notably,the warming aridification areas of desert steppe(92.68%)and sandy vegetation(90.24%)were significant.Climate warming was found to amplify the sensitivity of coniferous forest,deciduous forest,meadow steppe,and alpine steppe GPP to drought.Additionally,the drought sensitivity of vegetation GPP in the Mongolian Plateau gradually decreased as altitude increased.The cumulative effect of drought on vegetation GPP persisted for 3.00-8.00 months.The findings of this study will improve the understanding of how drought influences vegetation in arid and semi-arid areas. 展开更多
关键词 gross primary productivity(GPP) climate change warming aridification areas drought sensitivity cumulative effect duration(CED) Mongolian Plateau
下载PDF
Learning Effect and Productivity Convergence of Chinese Industrial Enterprises
9
作者 Tinghua Liu Jingru Wang Xiao Liu 《Journal of Finance Research》 2020年第2期92-105,共14页
The main purpose of this paper is to test the production efficiency of different Chinese property industrial enterprises.Based on the large sample panel data of industrial enterprises of the National Bureau of Statist... The main purpose of this paper is to test the production efficiency of different Chinese property industrial enterprises.Based on the large sample panel data of industrial enterprises of the National Bureau of Statistics,we found that although the production efficiency of China-funded enterprises is generally weaker than foreign-funded enterprises,some China-funded enterprises have better learning ability.On the one hand,dynamic analysis found that private enterprises have significant learning ability.On the other hand,the results of convergence analysis show that China’s private enterprises have the potential to gradually catch up with the frontier level of world production efficiency and have better learning ability to catch up potential.And state-owned enterprises tend to be more efficient at the beginning of their establishment,but their productivity is fairly slow to improve,especially for state-owned enterprises with high efficiency sub-samples,so that it’s hard for them to continue improving their efficiency.Institutional analysis found that the marketization process helped the China enterprises to improve their learning ability and China should continue to strengthen the reform of property rights and promote the marketization process. 展开更多
关键词 Production efficiency Learning effect Efficiency catch-up βconvergence analysis
下载PDF
The Effect of Performance Management System on Employee Productivity in Cross-Border E-Commerce Enterprises in China
10
作者 Yan Fang Taien Layraman 《Management Studies》 2022年第3期155-166,共12页
The aim of the current research was to analyze how the performance management system of China’s cross-border e-commerce enterprises affects employee productivity.The study was guided by the following research objecti... The aim of the current research was to analyze how the performance management system of China’s cross-border e-commerce enterprises affects employee productivity.The study was guided by the following research objectives:to investigate the performance management system on employee productivity in cross-border e-commerce enterprises in China;to determine the relationship between the performance management system and employee productivity in cross-border e-commerce enterprises in China.The study adopted a quantitative approach to the effects of performance management practices on employee productivity.The dependent variables included performance appraisals,reward systems,and performance feedback,and the implications on employee productivity as the independent variable.The target population is comprised of 400 employees in China’s cross-border e-commerce enterprises.Descriptive statistics were utilized as a data analysis tool.The demographic profiles of the respondents were analyzed using percentages and frequencies.Inferential statistics such as correlation and regression analysis established the relationship between dependent and independent variables.The study recommends that the performance management practices should be optimized to improve employee performance.Performance reviews should be focused on the contributions of the individual employees to meet the organizational objectives.For every possible opportunity,the manager should formally recognize good employee efforts for enhanced work performance.Effective performance management practices that edify appraisal and reward should be used to achieve organization goals and enhance employee productivity. 展开更多
关键词 performance management system performance appraisal performance feedback reward systems employee productivity cross-border e-commerce
下载PDF
Alternate cotton-peanut intercropping:a new approach to increasing productivity and minimizing environmental impact
11
作者 CHI Baojie DONG Hezhong 《Journal of Cotton Research》 CAS 2024年第1期101-103,共3页
Recent publications have highlighted the development of an alternate cotton-peanut intercropping as a novel strat-egy to enhance agricultural productivity.In this article,we provide an overview of the progress made in... Recent publications have highlighted the development of an alternate cotton-peanut intercropping as a novel strat-egy to enhance agricultural productivity.In this article,we provide an overview of the progress made in the alternate cotton-peanut intercropping,specifically focusing on its yield benefits,environmental impacts,and the underlying mechanisms.In addition,we advocate for future investigations into the selection or development of appropriate crop varieties and agricultural equipment,pest management options,and the mechanisms of root-canopy interactions.This review is intended to provide a valuable reference for understanding and adopting an alternate intercropping system for sustainable cotton production. 展开更多
关键词 COTTON PEANUT Alternate intercropping productivity
下载PDF
Biochar induced trade-offs and synergies between ecosystem services and crop productivity
12
作者 Jinxia Wang Qiu Huang +9 位作者 Kai Peng Dayang Yang Guozhen Wei Yunfei Ren Yixuan Wang Xiukang Wang Nangia Vinay Shikun Sun Yanming Yang Fei Mo 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第11期3882-3895,共14页
Biochar amendment offers a chance for sustainable agriculture.However,the effectiveness of biochar relies on its physical and chemical properties,which are heavily affected by biochar production conditions and managem... Biochar amendment offers a chance for sustainable agriculture.However,the effectiveness of biochar relies on its physical and chemical properties,which are heavily affected by biochar production conditions and management practices.Therefore,substantial uncertainties regarding the use of biochar exist in agricultural systems globally.This study provides the first quantitative evaluation of the impacts of biochar characteristics and management practices on key ecosystem services by performing a second-order meta-analysis based on 34,628 paired observations in biochar-amended and unamended systems.Overall,biochar enhances phytotoxicity alleviation,physiology regulation,soil remediation and carbon sequestration,and microbial functional gene abundance.However,some prominent trade-offs exist between crop productivity and ecosystem service deliveries including for nutrient cycling,microbial function,climate change mitigation,and the soil microbial community.The adoption of low C:N biochar produced at high pyrolysis temperatures from sewage sludge-derived feedstock,in combination with a moderate application rate and inorganic fertilizer input,shows potential for achieving synergistic promotion of crop productivity and ecosystem services.These outcomes highlight the need for judicious implementation of biochar-based solutions to site-specific soil constraints.The quantified synergy and tradeoff relationships will aid the establishment of a sustainable biochar development framework that strengthens necessary ecosystem services commensurate with food security assurance. 展开更多
关键词 BIOCHAR soil remediation phytotoxicity alleviation carbon sequestration productivity
下载PDF
The multiple roles of crop structural change in productivity,nutrition and environment in China:A decomposition analysis
13
作者 Xiangyang Zhang Yumei Zhang Shenggen Fan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第5期1763-1773,共11页
China's crop structure has undergone significant changes in the last two decades since 2000,with an increase in the share of cereals,vegetables,and fruit,squeezing out other crops.As a result,land productivity,nut... China's crop structure has undergone significant changes in the last two decades since 2000,with an increase in the share of cereals,vegetables,and fruit,squeezing out other crops.As a result,land productivity,nutrient supply,and carbon emissions have changed.How to reallocate limited farmland among crops to achieve the multiple goals of agrifood systems becomes an important issue.This study explores the sources of land productivity and nutrition supply growth and carbon emissions reduction,and identifies the multiple roles of crop structural change from 2003 to 2020 based on a decomposition analysis.The results reveal that the growth within crops is still the primary driver in land productivity and nutrition supply and the reduction in carbon emissions.However,structural change also plays various roles at different periods.From 2003 to 2010,crop structural change increased the total calorie supply but lowered land productivity and contributed at least 70%of the total growth of carbon emissions.The crop structure was relatively stable,and their effects were modest from 2010 to 2015.From 2015 to 2020,the crop structural change began to play a greater role and generate synergistic effects in improving land productivity,micronutrient supply,and reducing carbon emissions,contributing to approximately a quarter of the growth of land productivity and 30%of total carbon emissions reduction.These results suggest that strategies for crop structural change should comprehensively consider its multiple impacts,aiming to achieve co-benefits while minimizing trade-offs. 展开更多
关键词 CROP structural change land productivity NUTRITION carbon emissions
下载PDF
Effect of Fertilizers on the Productivity of Maize (Zea mays L.) Cultivated in the Zinder Region (Niger Republic)
14
作者 Oumarou Zango Abdoulaye Moussa Oumarou +4 位作者 Abdou Harou Brah Mahamadou Salissou So Timothée Kouassi Agbo Yacoubou Bakasso Rabiou Abdou 《Agricultural Sciences》 2024年第11期1340-1351,共11页
Maize constitutes one of the most important crops in Niger’s fight for food security, and it is cultivated in all regions of the country. However, maize cultivation is declining due to low soil fertility. This study ... Maize constitutes one of the most important crops in Niger’s fight for food security, and it is cultivated in all regions of the country. However, maize cultivation is declining due to low soil fertility. This study focused on evaluating the impact of fertilizers on maize plant production in Zinder. The fertilizer effect was evaluated based on 21 quantitative and 9 qualitative descriptors proposed by IBPGR and CIMMYT 1991. The experiment was conducted during the rainy season in the experimental domain of Université André Salifou following randomized complete block designs with three repetitions. Seven fertilizer treatments, including two organic, two mineral, two combinations of fertilizers, and a control treatment, were applied. The analysis shows that fertilizers had positive effects on the earliness and productivity of the selected variety. The best yield of dry corn cob (7480 kg/ha) was recorded on organic fertilizer of composted poultry manure, which is equal to 4.8 times that obtained with the control (1561 kg/ha), followed by the mineral fertilizer NPK combined with composted cow dung with 6395.231 kg/ha. Therefore, the use of fertilizers could be an appropriate alternative to overcome the negative consequences of yield declines in the corn production system in the Zinder region. 展开更多
关键词 MAZE Organic Fertilizer Mineral Fertilizers productivity Zinder
下载PDF
How forest age impacts on net primary productivity: Insights from future multi-scenarios
15
作者 Lei Tian Yu Tao +2 位作者 Simms Joanna Annikki Mäakelä Mingyang Li 《Forest Ecosystems》 SCIE CSCD 2024年第5期708-719,共12页
Forest net primary productivity(NPP)constitutes a key flux within the terrestrial ecosystem carbon cycle and serves as a significant indicator of the forests carbon sequestration capacity,which is closely related to f... Forest net primary productivity(NPP)constitutes a key flux within the terrestrial ecosystem carbon cycle and serves as a significant indicator of the forests carbon sequestration capacity,which is closely related to forest age.Despite its significance,the impact of forest age on NPP is often ignored in future NPP projections.Here,we mapped forest age in Hunan Province at a 30-m resolution utilizing a combination of Landsat time series stack(LTSS),national forest inventory(NFI)data,and the relationships between height and age.Subsequently,NPP was derived from NFI data and the relationships between NPP and age was built for various forest types.Then forest NPP was predicted based on the NPP-age relationships under three future scenarios,assessing the impact of forest age on NPP.Our findings reveal substantial variations in forest NPP in Hunan Province under three future scenarios:under the age-only scenario,NPP peaks in 2041(133.56TgC·yr^(−1)),while NPP peaks three years later in 2044(141.14TgC·yr^(−1))under the natural development scenario.The maximum afforestation scenario exhibits the most rapid increase in NPP,with peaking in 2049(197.95TgC·yr^(−1)).However,with the aging of the forest,NPP is projected to then decrease by 7.54%,6.07%,and 7.47%in 2060,and 20.05%,19.74%,and 28.38%in 2100,respectively,compared to their peaks under the three scenarios.This indicates that forest NPP will continue to decline soon.Controlling the age structure of forests through selective logging,afforestation and reforestation,and encouraging natural regeneration after disturbance could mitigate this declining trend in forest NPP,but implications of these measures on the full forest carbon balance remain to be studied.Insights from the future multi-scenarios are expected to provide data to support sustainable forest management and national policy development,which will inform the achievement of carbon neutrality goals by 2060. 展开更多
关键词 Net primary productivity Forest age NPP-Age relationships NPP projections AFFORESTATION
下载PDF
Oilfield analogy and productivity prediction based on machine learning: Field cases in PL oilfield, China
16
作者 Wen-Peng Bai Shi-Qing Cheng +3 位作者 Xin-Yang Guo Yang Wang Qiao Guo Chao-Dong Tan 《Petroleum Science》 SCIE EI CAS CSCD 2024年第4期2554-2570,共17页
In the early time of oilfield development, insufficient production data and unclear understanding of oil production presented a challenge to reservoir engineers in devising effective development plans. To address this... In the early time of oilfield development, insufficient production data and unclear understanding of oil production presented a challenge to reservoir engineers in devising effective development plans. To address this challenge, this study proposes a method using data mining technology to search for similar oil fields and predict well productivity. A query system of 135 analogy parameters is established based on geological and reservoir engineering research, and the weight values of these parameters are calculated using a data algorithm to establish an analogy system. The fuzzy matter-element algorithm is then used to calculate the similarity between oil fields, with fields having similarity greater than 70% identified as similar oil fields. Using similar oil fields as sample data, 8 important factors affecting well productivity are identified using the Pearson coefficient and mean decrease impurity(MDI) method. To establish productivity prediction models, linear regression(LR), random forest regression(RF), support vector regression(SVR), backpropagation(BP), extreme gradient boosting(XGBoost), and light gradient boosting machine(Light GBM) algorithms are used. Their performance is evaluated using the coefficient of determination(R^(2)), explained variance score(EV), mean squared error(MSE), and mean absolute error(MAE) metrics. The Light GBM model is selected to predict the productivity of 30 wells in the PL field with an average error of only 6.31%, which significantly improves the accuracy of the productivity prediction and meets the application requirements in the field. Finally, a software platform integrating data query,oil field analogy, productivity prediction, and knowledge base is established to identify patterns in massive reservoir development data and provide valuable technical references for new reservoir development. 展开更多
关键词 Data mining technique Analogy parameters Oilfield analogy productivity prediction Software platform
下载PDF
Plastic mulch increases dryland wheat yield and water-use productivity,while straw mulch increases soil water storage
17
作者 Hubing Zhao Guanfei Liu +5 位作者 Yingxia Dou Huimin Yang Tao Wang Zhaohui Wang Sukhdev Malhi Adnan Anwar Khan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第9期3174-3185,共12页
Amplifying drought stress and high precipitation variability impair dryland wheat production.These problems can potentially be minimized by using plastic mulch(PM)or straw mulch(SM).Therefore,wheat grain yield,soil wa... Amplifying drought stress and high precipitation variability impair dryland wheat production.These problems can potentially be minimized by using plastic mulch(PM)or straw mulch(SM).Therefore,wheat grain yield,soil water storage,soil temperature and water-use productivity of PM and SM treatments were compared with no mulch(CK)treatment on dryland wheat over a period of eight seasons.Compared to the CK treatment,PM and SM treatments on average significantly increased grain yield by 12.6 and 10.5%,respectively.Compared to the CK treatment,SM treatment significantly decreased soil daily temperature by 0.57,0.60 and 0.48℃ for the whole seasons,growing periods and summer fallow periods,respectively.In contrast,compared to the CK treatment,PM treatment increased soil daily temperature by 0.44,0.51 and 0.27℃ for the whole seasons,growing periods and summer fallow periods,respectively.Lower soil temperature under SM allowed greater soil water storage than under PM.Soil water storage pre-seeding was 17%greater under the SM than under the PM treatment.Soil water storage post-harvest was similar for the PM and SM treatments,but evapotranspiration was 4.5%higher in the SM than in the PM treatment.Consequently,water-use productivity was 6.6%greater under PM than under the SM treatment.Therefore,PM treatment increased dryland wheat yield and water-use productivity,while straw mulch increased soil water storage. 展开更多
关键词 plastic mulch soil water storage straw mulch water-use productivity winter wheat
下载PDF
Analysis of Spatiotemporal Changes in Integrated Land Productivity in Chongqing from 1997 to 2023
18
作者 Lei LUO Jinrong YANG 《Asian Agricultural Research》 2024年第8期1-5,49,共6页
[Objectives]Integrated land productivity can reflect the comprehensive utilization of land and the overall output level,which is the most basic and commonly used indicator in assessing land use efficiency.This thesis ... [Objectives]Integrated land productivity can reflect the comprehensive utilization of land and the overall output level,which is the most basic and commonly used indicator in assessing land use efficiency.This thesis aims to analyze the spatial and temporal changes of integrated land productivity in Chongqing from 1997 to 2023 in order to assess its land use efficiency.[Methods]This study measured the integrated land productivity of Chongqing Municipality,the only municipality directly under the central government in the western part of China,over the past 26 years(1997-2023)through relevant surveys and statistical data,and analyzed in depth the integrated land productivity of the 38 districts and counties under the jurisdiction of Chongqing,as well as the functional sub-districts of the"one district and two clusters"and the"one district and two clusters"in Chongqing.It also analyzes the characteristics of spatial and temporal differences in land productivity in 38 districts and counties under the jurisdiction of Chongqing and"one district and two clusters".[Results]The results of the study show that over the past 26 years,the integrated land productivity of Chongqing has shown an annual growth trend,and the integrated land productivity of the 38 districts and counties and the functional subregions of"one district and two clusters"has also increased significantly,but the average annual growth rate of the integrated land productivity varies among different regions.From the perspective of spatial differences,there are significant differences in land productivity among the 38 districts and counties of Chongqing and the functional subregions of"one district and two clusters",which are mainly due to the different natural conditions,economic development levels and functional positioning of each region.[Conclusions]Based on the results of the study and the actual situation of Chongqing,this paper puts forward the leading measures to improve the integrated land productivity,with a view to providing a reference basis for Chongqing to improve the efficiency of land use and promote the sustainable use of land resources. 展开更多
关键词 INTEGRATED LAND productivity Spatial and TEMPORAL changes CHONGQING
下载PDF
Productivity Prediction Model of Perforated Horizontal Well Based on Permeability Calculation in Near-Well High Permeability Reservoir Area
19
作者 Shuangshuang Zhang Kangliang Guo +3 位作者 Xinchen Gao Haoran Yang Jinfeng Zhang Xing Han 《Energy Engineering》 EI 2024年第1期59-75,共17页
To improve the productivity of oil wells,perforation technology is usually used to improve the productivity of horizontal wells in oilfield exploitation.After the perforation operation,the perforation channel around t... To improve the productivity of oil wells,perforation technology is usually used to improve the productivity of horizontal wells in oilfield exploitation.After the perforation operation,the perforation channel around the wellbore will form a near-well high-permeability reservoir area with the penetration depth as the radius,that is,the formation has different permeability characteristics with the perforation depth as the dividing line.Generally,the permeability is measured by the permeability tester,but this approach has a high workload and limited application.In this paper,according to the reservoir characteristics of perforated horizontal wells,the reservoir is divided into two areas:the original reservoir area and the near-well high permeability reservoir area.Based on the theory of seepage mechanics and the formula of open hole productivity,the permeability calculation formula of near-well high permeability reservoir area with perforation parameters is deduced.According to the principle of seepage continuity,the seepage is regarded as the synthesis of two directions:the horizontal plane elliptic seepage field and the vertical plane radial seepage field,and the oil well productivity prediction model of the perforated horizontal well is established by partition.The model comparison demonstrates that the model is reasonable and feasible.To calculate and analyze the effect of oil well production and the law of influencing factors,actual production data of the oilfield are substituted into the oil well productivity formula.It can effectively guide the technical process design and effect prediction of perforated horizontal wells. 展开更多
关键词 Perforated horizontal well PERMEABILITY productivity model sensitivity analysis
下载PDF
Analysis of Regional Difference of Agricultural Land Productivity in Heilongjiang Province
20
作者 Linlin CAO Jinrong YANG Shiqin YANG 《Asian Agricultural Research》 2024年第8期9-13,16,共6页
The sustenance of humanity is contingent upon the production of food.The foundation of this production is agriculture,which in turn is dependent upon the cultivation of the land.As a fundamental element of agricultura... The sustenance of humanity is contingent upon the production of food.The foundation of this production is agriculture,which in turn is dependent upon the cultivation of the land.As a fundamental element of agricultural advancement,the rational development and utilization of land play a pivotal role in the process of rural revitalization.Agricultural land productivity serves as a principal indicator of the efficacy of land utilization and the extent of agricultural advancement.Nevertheless,there is a paucity of research examining the productivity of agricultural land,particularly a lack of specialized research on large agricultural provinces.In light of the aforementioned considerations,this paper presents a comprehensive examination of agricultural land productivity and its regional variations in Heilongjiang Province in 2022,with the aid of pertinent statistical data.The findings of the analysis indicate that among the prefecture-level cities,Daqing and Suihua exhibit the highest levels of agricultural land productivity.Additionally,Zhaodong City,Zhaozhou,Qinggang,Wangkui,and Lanxi counties exhibit high levels of agricultural land productivity within their respective prefecture-level cities.There are notable disparities in agricultural land productivity across various regions,including Yichun,Heihe,Harbin,Daqing,Hegang,and Suihua.In contrast,other regions demonstrate a more balanced spatial distribution.In order to facilitate the prosperous development of the agricultural industry in Heilongjiang Province,it is essential to optimize the spatial planning of the land,to investigate the potential for agricultural development in each region,to establish effective collaboration between resources and industries,and to create a development synergy that will collectively advance rural revitalization. 展开更多
关键词 AGRICULTURAL LAND productivity REGIONAL DIFFERENCE Heilongjiang PROVINCE
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部