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Effects of land-use pattern change on rainfall-runoff and runoff-sediment relations:a case study in Zichang watershed of the Loess Plateau of China 被引量:12
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作者 ZHAOWen-wu FUBo-jie +2 位作者 mengqing-hua ZHANGQiu-ju ZHANGYin-hui 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2004年第3期436-442,共7页
The purpose of this article is to identify the effect of land use pattern on rainfall runoff and runoff sediment relations in Zichang Watershed of the Loess Plateau. From 1986 to 1997, many farmlands changed into g... The purpose of this article is to identify the effect of land use pattern on rainfall runoff and runoff sediment relations in Zichang Watershed of the Loess Plateau. From 1986 to 1997, many farmlands changed into grassland or woodland, especially the farmland in steep slope positions or far away from the river. The change of land use pattern altered the rainfall runoff and runoff sediment relationships, and led to higher slope of trend curves(STCs) of annual rainfall runoff mass curve and runoff sediment mass curve in 1990s than that in 1980s. It is implied that more soil and water loss yielded in 1990s. In order to reduce soil loss, more attentions should be paid to land use pattern and some grass or other herbaceous filter strips should be built along rivers. 展开更多
关键词 land use RAINFALL RUNOFF sediment concentration double mass curve slope of trend curve Loess Plateau
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Improvement of Similarity Measure: Pearson Product-Moment Correlation Coefficient 被引量:5
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作者 LIUYong-suo mengqing-hua CHENRong WANGJian-song JIANGShu-min HUYu-zhu 《Journal of Chinese Pharmaceutical Sciences》 CAS 2004年第3期180-186,共7页
Aim To study the reason of the insensitiveness of Pearson product-momentcorrelation coefficient as a similarity measure and the method to improve its sensitivity. MethodsExperimental and simulated data sets were used.... Aim To study the reason of the insensitiveness of Pearson product-momentcorrelation coefficient as a similarity measure and the method to improve its sensitivity. MethodsExperimental and simulated data sets were used. Results The distribution range of the data setsinfluences the sensitivity of Pearson product-moment correlation coefficient. Weighted Pearsonproduct-moment correlation coefficient is more sensitive when the range of the data set is large.Conclusion Weighted Pearson product-moment correlation coefficient is necessary when the range ofthe data set is large. 展开更多
关键词 chromatographic fingerprints SIMILARITY quality control weighted pearsonproduct-moment correlation coefficient
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Eco-environment contribution of agroforestry to agriculture development in the plain area of China—Huai'an Prefecture, Jiangsu Province as the case study area
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作者 RENHong-chang LUYong-long +2 位作者 LIUCan mengqing-hua SHIYa-juan 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2005年第2期327-331,共5页
For improving the environmental quality and ensuring supply of wood and non-timber forest products, many forests have been planted in plain areas of China. Scientists have studied their benefits, almost all of the app... For improving the environmental quality and ensuring supply of wood and non-timber forest products, many forests have been planted in plain areas of China. Scientists have studied their benefits, almost all of the approaches were based on fixed-point data, and few was considered on the non-efficient factors and temporal scale effects. This paper studies the positive and negative benefits at a large temporal scale, and the effects of plain afforestation on stockbreeding and rural economy. The benefits of plain afforestation, correlation coefficiency of agroforestry and production factors are analyzed via stochastic frontier modeling in Huanghuaihai Plain Area of China; elastic coefficient of agroforestry, husbandry, farming, and total output of agricultural sector are calculated through adopting partial differential equation. Some conclusions can be drawn that, plain forests have an important effect on the development of plain agriculture. But shelterbelts and small-scale forests have different effect on the development of agricultural economy. Shelterbelts have negative effect on the industries, but small-scale forest has positive effect. On the whole, contribution of forest resource to value of animal husbandry and gross production value of agriculture is positive, and to the value of farming is negative. 展开更多
关键词 plain afforestation agricultural development AGROFORESTRY plain area of China
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破解ICT生产率悖论之谜——基于微观视角的前沿综述 被引量:3
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作者 何小钢 华梦清 《产业经济评论(山东)》 2020年第1期1-17,共17页
随着人工智能、机器人等新一代ICT逐步在中国大规模应用,ICT能否赋能企业推动全要素生产率增长,成为重要的理论与现实问题。本文从国家、行业和企业3个层面梳理ICT生产率悖论的演进趋势发现,基于国家和行业的宏观研究与基于企业的微观... 随着人工智能、机器人等新一代ICT逐步在中国大规模应用,ICT能否赋能企业推动全要素生产率增长,成为重要的理论与现实问题。本文从国家、行业和企业3个层面梳理ICT生产率悖论的演进趋势发现,基于国家和行业的宏观研究与基于企业的微观研究存在明显的分野,前者结论不确定,后者否定存在悖论。进一步地,从微观视角对破解悖论的理论机制与路径进行了综述。ICT投资通过与组织结构、生产流程、创新行为和劳动力技能等互补性组织行为和组织资源相互匹配才能使生产率获得有效提升,这种互补效应正是弥合宏观与微观研究结论鸿沟的有效机制。最后从政府和企业角度,给出了优化中国企业智能化战略的思路和对策,提出了进一步研究方向。 展开更多
关键词 信息通信技术 生产率悖论 微观视角 突破路径 全要素生产率
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