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协同创新计划在江苏高等农职院校的实践与创新 总被引:1,自引:1,他引:0
启动实施高等学校创新能力提升计划,即协同创新计划,简称"2011计划",是提升国家创新能力的重要手段和战略选择,是全面提高高等教育质量的重要着力点。文章阐述了江苏高校协同创新计划实施的现状,论述了江苏高等农职院校协同创新计划的实践与创新,指出江苏高等农职院校坚持行业特色,找准协同方向,创新性建设校企合作联盟载体,可以显著提高服务区域经济发展的水平与能力,提升办学的综合实力和核心竞争力,为社会输送大批合格人才,为地方经济建设作出更大贡献。 相似文献
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Estimating aboveground biomass of Pinus densata-dominated forests using Landsat time series and permanent sample plot data 总被引:3,自引:0,他引:3
Southwest China is one of three major forest regions in China and plays an important role in carbon sequestration.Accurate estimations of changes in aboveground biomass are critical for understanding forest carbon cycling and promoting climate change mitigation.Southwest China is characterized by complex topographic features and forest canopy structures,complicating methods for mapping aboveground biomass and its dynamics.The integration of continuous Landsat images and national forest inventory data provides an alternative approach to develop a long-term monitoring program of forest aboveground biomass dynamics.This study explores the development of a methodological framework using historical national forest inventory plot data and Landsat TM timeseries images.This method was formulated by comparing two parametric methods:Linear Regression for Multiple Independent Variables(MLR),and Partial Least Square Regression(PLSR);and two nonparametric methods:Random Forest(RF)and Gradient Boost Regression Tree(GBRT)based on the state of forest aboveground biomass and change models.The methodological framework mapped Pinus densata aboveground biomass and its changes over time in Shangri-la,Yunnan,China.Landsat images and national forest inventory data were acquired for 1987,1992,1997,2002 and 2007.The results show that:(1)correlation and homogeneity texture measures were able to characterize forest canopy structures,aboveground biomass and its dynamics;(2)GBRT and RF predicted Pinus densata aboveground biomass and its changes better than PLSR and MLR;(3)GBRT was the most reliable approach in the estimation of aboveground biomass and its changes;and,(4)the aboveground biomass change models showed a promising improvement of prediction accuracy.This study indicates that the combination of GBRT state and change models developed using temporal Landsat and national forest inventory data provides the potential for developing a methodological framework for the long-term mapping and monitoring program of forest aboveground biomass and its changes in Southwest China. 相似文献
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功率因数校正(PFC)电路作为谐波补偿装置和提高功率因数的有效措施已成为电力电子技术研究的热点问题,且绝大多数PFC采用Boost电路,在中等及以上功率等级时PFC常采用电流连续模式,而功率二极管由于存在反向恢复特性,开关管的开通损耗被大大增加,电磁干扰加重。本文提出了一种新的电容型无源无损缓冲电路,其能够抑制二极管的反向恢复特性,减小开关管的开通损耗,提高PFC的效率。电路结构简单,软开关实现范围大,500W实验样机验证了PFC在半载时效率能提高1.08%。 相似文献
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车辆在城市道路上行驶时,很多能量在制动时被制动器耗散掉,采用制动能量回收技术将该部分能量收集起来,能有效提高车辆的行驶里程。以运输车为对象,在分析永磁无刷直流电机发电特性和Boost电路(开关直流升压电路)特性的基础上,设计了一种基于国产集成电路的双Boost电路的能量回收控制器。制动中该控制器能使永磁无刷直流电机提供一个平稳的制动力矩,同时将发出的7~55 V电压升压到所需要的充电电压。 相似文献
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A new type AC DC AC converter which can work in Buck or Boost mode is proposed in order to overcome the deficiencies of the primary circuit of the traditional contactless power transfer system. Through switching this two modes and turning the duty cycles of the switches, not only the resonant current amplitude of the primary resonant current can be controlled to be constant against a wide range variation of input voltage, but also the problems, such as surge current, high cost, complex control etc., caused by the DC filter and DC/DC converter in a traditional CPT system are effectively eliminated. The topology and operation principle of the proposed converter have been analyzed. The corresponding control strategy has been presented and verified by simulation results. 相似文献
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