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温室黄瓜叶片光合速率的类卡方模型 被引量:9
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作者 李萍萍 李冬生 +1 位作者 王纪章 付为国 《农业工程学报》 EI CAS CSCD 北大核心 2009年第1期171-175,共5页
为了精确模拟不同光照下温室黄瓜光合作用的变化规律,提出了一种类卡方模型(QCSM)进行建模。使用Li-6400便携式光合测定系统测定了温度分别为16℃、20℃、24℃、26℃、28℃、30℃和光量子流通量密度(PPFD)为0~2000μmol/(m2·s)动... 为了精确模拟不同光照下温室黄瓜光合作用的变化规律,提出了一种类卡方模型(QCSM)进行建模。使用Li-6400便携式光合测定系统测定了温度分别为16℃、20℃、24℃、26℃、28℃、30℃和光量子流通量密度(PPFD)为0~2000μmol/(m2·s)动态条件下温室黄瓜叶片净光合速率(Pn),以Pn测定值为基础对QCSM参数进行了模拟。结果表明:QCSM拟合得到的黄瓜叶片净光合速率估计值Pn与实测值Pn相符。经过前一年的数据验证,模型精度较高,拟合优度达0.9908,残差标准误差(RSE)为0.4537。与负指数模型(ME)相比,QCSM净光合速率估计值与实测值较接近,同时,QCSM能得到包括光饱和点、补偿点、最大光合速率、暗呼吸、表观量子效率等在内的五个光合作用参数值。与非直角模型(NRH)相比,由QCSM估计的光饱和点、补偿点、暗呼吸与实际较接近。 展开更多
关键词 类卡方模型 温室 黄瓜 净光合速率
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Regional Clustering and Synchronization of Provincial Business Fluctuations in China 被引量:2
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作者 SONG Tao ZHENG Tingguo XIA Kai 《Chinese Geographical Science》 SCIE CSCD 2018年第4期571-583,共13页
In this article, we propose a novel, multilevel, dynamic factor model, to determine endogenously clustered regions for the investigation of regional clustering and synchronization of provincial business fluctuations i... In this article, we propose a novel, multilevel, dynamic factor model, to determine endogenously clustered regions for the investigation of regional clustering and synchronization of provincial business fluctuations in China. The parameter identification and model estimation was conducted using the Markov Chain Monte Carlo method. We then conducted an empirical study of the provincial business fluctuations in China(31 Chinese provinces are considered except Hong Kong, Macao, and Taiwan due to the data unavailability), which were sampled from January 2000 to December 2015. Our results indicated that these provinces could be clustered into four regions: leading, coincident, lagging, and overshooting. In comparison with traditional geographical divisions, this novel clustering into four regions enabled the regional business cycle synchronization to be more accurately captured. Within the four regional clusters it was possible to identify substantial heterogeneities among regional business cycle fluctuations, especially during the periods of the 2008 financial crisis and the ‘four-trillion economic stimulus plan'. 展开更多
关键词 regional division business cycle synchronization multilevel dynamic factor model variance decomposition
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