利用遥感光谱无损、快速分析出氮肥的施用时期和施用模式,对于保护环境、产量及氮肥利用率的提高具有重要意义。利用FieldSpec 4Wide-Res Field Spectrum radiometer便携式地物光谱仪,测定了不同氮水平下小麦冠层和叶片两种模式光谱特...利用遥感光谱无损、快速分析出氮肥的施用时期和施用模式,对于保护环境、产量及氮肥利用率的提高具有重要意义。利用FieldSpec 4Wide-Res Field Spectrum radiometer便携式地物光谱仪,测定了不同氮水平下小麦冠层和叶片两种模式光谱特征及红边参数变化规律;提出一个新指数——归一化差异最大指数(normalized difference maximum index,NDMI),并分析其与叶面积指数(leaf area index,LAI)、SPAD(soil and plant analyzer development)值、MDA(malondialdehyde)含量、旗叶氮含量和产量的相关性。结果表明,小麦叶片原始光谱在开花后26d起800～1 330nm区间的光谱反射率以N3(1/3底施+1/3冬前追肥+1/3拔节期追肥)处理为最高,N1处理(1/2底施+1/2冬前追肥)次之。主要原因是由冬前和拔节期两个时期均施三分之一氮肥,增强了叶片光合能力。小麦冠层原始光谱,在400～700nm波段,N2(1/2底施+1/2拔节期追肥)处理最低;在760～1 368nm波段区间,由于群体结构不同,在开花期至灌浆中期N1处理的光谱反射率最高,N3处理次之;N3处理的冠层光谱反射率在开花后26和33d最高。建议用400～700和760～1 368nm波段的冠层原始光谱数据,分别来辨别小麦旗叶含氮量的高低及施肥模式。叶片模式下一阶微分光谱在500～750nm区间出现两个"峰",通过峰的位置偏移程度和偏移时期来估测施氮的模式。在670～740nm区间冠层一阶微分光谱值在开花期最高,开花后10d的一阶微分光谱值最低。在开花期至开花后10d N1处理的一阶微分光谱值高于N3处理;灌浆中期至开花后33dN3处理的一阶微分光谱值高于N1处理。可以通过一阶微分最大值来推测小麦所处的生育期和施肥的方式及施肥时期。在开花期至灌浆中期,冠层反射率一阶导数最大值(FD-Max)N1处理最高,N3处理次之;在开花后26～33d,N3处理的群体结构较其他处理密,导致其一阶导数最大值一直最高。四个处理叶片一阶导数最大值变化趋势不如冠层显著。四个处理的反射率一阶导数最大值对应的红边位置(REPFD-Max)中,N1和N3冠层REPFD-Max在灌浆中期后偏移显著;在开花后26～33d,N3处理的群体上层结构密,叶片宽且厚,冬前追施氮肥影响REPFD-Max偏移程度。基于NDVI基础上,筛选出一个新指数——归一化差异最大指数。冠层归一化差异最大指数(CNDMI)与农化参数的相关系数高于叶片归一化差异最大指数(LNDMI),且CNDMI与产量的相关性比LNDMI显著。冠层归一化差异最大指数与旗叶氮含量、SPAD值和MDA含量有着显著的相关性,相关系数r分别为0.812 88,0.928 21和-0.722 17。综上所述,借助光谱数据和红边参数可以推测小麦含氮量的高低,所处的生育期和施氮肥的模式,进而为田间施肥管理及施肥诊断提供依据。CNDMI与小麦产量有着更好的相关性,符合我国资源卫星的光谱波段范围,具有可实际操作性。展开更多
[Objective] This study aimed to establish models based on atmospheric cir- culation indices for forecasting the area attacked by rice planthopper every year, and to provide guide for preventing and controlling plantho...[Objective] This study aimed to establish models based on atmospheric cir- culation indices for forecasting the area attacked by rice planthopper every year, and to provide guide for preventing and controlling planthopper damage. [Method] The data related to rice planthopper occurrence and atmospheric circulation were collected and analyzed with the method of stepwise regression to establish the prediction models. [Result] The factors significantly related to the area attacked by rice plan-thopper were selected. Two types of prediction models were established. One was for Sogatella furcifera （Horvath）, based on Atlantic-Europe circulation pattern W in October in that year, Pacific polar vortex area index in October in that year, North America subtropical high index in August in that year, Atlantic-Europe circulation pattern W in June in that year, northern boundary of North America subtropical high in February in that year, Atlantic-Europe polar vortex intensity index in October in that year and Asia polar vortex intensity index in November in the last year; the other type of prediction models were for Nilaparvata lugens （Stal）, based on the Eastern Pacific subtropical high intensity index in July in that year, northern hemi- sphere polar vortex area index in October in the last year, Asia polar vortex strength index in November in the last year, north boundary of North America-At- lantic subtropical high in September in that year, north boundary of North Africa-At- lantic-North America subtropical high in January in that year, sunspot in September of the last year and eastern Pacific subtropical high area index in September in that year. [Conclusion] With the stepwise regression, the forecasting equations of the rice planthopper occurrence established based on the atmospheric circulation indices could be used for actual forecast.展开更多
[Objective] The aim was to research macrobenthos community structure and its relations with environmental factors in three reservoirs. [Method] Benthic diversity and water quality of Yuqiao Reservoir, Beidagang Reserv...[Objective] The aim was to research macrobenthos community structure and its relations with environmental factors in three reservoirs. [Method] Benthic diversity and water quality of Yuqiao Reservoir, Beidagang Reservoir and Er- wangzhuang Reservoir were investigated in May, July and September 2011, respec- tively. []Result] Of all the 14 sampling sites, 22 species of macroinvertebrates were collected, totally, which included 6 species of aquatic insects, 7 species of Mollusca, 2 species of Crustacean, 7 species of Oligochaeta. The species of macroinverte- brates during May, July and September in Yuqiao reservoir were 11, 8 and 10, respectively. The dominant species were Chironomus sinicus, and Monopylephorus limosus. The average density and biomass of the macrobenthos were 132.43 ind./m2 and 50.09 g/m2. Yuqiao reservoir was mostly at status of premediate polluted, according to the Margalef index, Shannon index and Pielou index. The species of during May, July and September in Beidagang reservoir were 5 5 and 5, respectively. The dominant species were Chironomus sinicus, Penaeus vannamei. The average density and biomass of the macrobenthos were 218 ind./m2 and 2.70 g/m2. Beidagang reservoir was mostly at status of heavy polluted, accord- ing to the Margalef index, Shannon-wiener index, Pielou index. The species of during May, July and September in Erwangzhuang reservoir were 3, 5 and 5, respectively. The dominant species were Monopylephorus limosus, Chi- ronomus sinicus. The average density and biomass of the macrobenthos were 104 ind/m2 and 0.20 g/m2. Erwangzhuang reservoir was mostly at status of intermediate polluted, according to the Margalef index, Shannon index, Pielou index. The density of zoobenthos in Yuqiao Reservoir was positively significantly correlated with TP （P〉 0.05）, negatively correlated with NH4＋-N （P〉0.05）, positively correlated with COD （P〈 0.01）, not significantly correlated with other environment factors （P〉0.05）. There was no significant correlation between biomass of zoobenthos and environment factors. The density of zoobenthos in Beidagang Reservoir with NH4＋-N was positively signif- icantly correlated （P〈0.05）, not significantly correlated with other aquatic environment factors （P〉0.05）. There was no significant correlation between biomass of zoobenthos and environment factors. The density of zoobenthos in Erwangzhuang Reser- voir with NO3-N was positively significantly correlated （P〈0.05）, not significant cor- related with other aquatic environment factors （F〉0.05）. The biomass of zoobenthos in Erwangzhuang Reservoir with NH4＋-N was positively significantly correlated （P〈 0.05）, not significant correlated with other aquatic environment factors （P〉0.05）. [Conclusion] It is indicated that this three reservoirs were all eutrophied and polluted, and the eurephication extent change of water in three reservoirs is as follows： Beidagang reservoir〉Erwangzhuang reservoir〉Yuqiao reservoir.展开更多
The local chaos characteristics of the time series pressure fluctuations of gas liquid two phase flow in a self aspirated reversed flow jet loop reactor are studied by the deterministic chaos analysis technique. It...The local chaos characteristics of the time series pressure fluctuations of gas liquid two phase flow in a self aspirated reversed flow jet loop reactor are studied by the deterministic chaos analysis technique. It is found that the estimated local largest Lyapunov exponent is positive in all cases and the profile is similar to that of the local fractal dimension in this reactor. The positive largest Lyapunov exponent shows that the reactor is a nonlinear chaotic system. The obvious distribution indicates that the local nonlinear characteristic parameters such as the Lyapunov exponent and the fractal dimension could be applied to further study the flow characteristics such as the flow regine transitions and flow structures of the multi phase reactors.展开更多
Hursts rescaled range (R/S) analysis and Wolfs attractor reconstruction technique have been adopted to estimate the local fractal dimensions and the local largest Lyapunov exponents in terms of the time series pressur...Hursts rescaled range (R/S) analysis and Wolfs attractor reconstruction technique have been adopted to estimate the local fractal dimensions and the local largest Lyapunov exponents in terms of the time series pressure fluctuations obtained from a gas liquid solid three phase self aspirated reversed flow jet loop reactor,respectively.The results indicate that the local fractal dimensions and the local largest Lyapunov exponents in both the jet region and the tubular region inside the draft tube increase with the increase in the jet liquid flowrates and the solid loadings,the local fractal dimension profiles are similar to those of the largest Lyapunov exponent,the local largest lyapunov exponents are positive for all cases,and the flow behavior of such a reactor is chaotic.The local nonlinear characteristic parameters such as the local fractal dimension and the local largest Lyapunov exponent could be applied to further study the flow properties such as the flow regime transitions and flow structures of this three phase jet loop reactor.展开更多
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(200903051)~~
文摘[Objective] This study aimed to establish models based on atmospheric cir- culation indices for forecasting the area attacked by rice planthopper every year, and to provide guide for preventing and controlling planthopper damage. [Method] The data related to rice planthopper occurrence and atmospheric circulation were collected and analyzed with the method of stepwise regression to establish the prediction models. [Result] The factors significantly related to the area attacked by rice plan-thopper were selected. Two types of prediction models were established. One was for Sogatella furcifera （Horvath）, based on Atlantic-Europe circulation pattern W in October in that year, Pacific polar vortex area index in October in that year, North America subtropical high index in August in that year, Atlantic-Europe circulation pattern W in June in that year, northern boundary of North America subtropical high in February in that year, Atlantic-Europe polar vortex intensity index in October in that year and Asia polar vortex intensity index in November in the last year; the other type of prediction models were for Nilaparvata lugens （Stal）, based on the Eastern Pacific subtropical high intensity index in July in that year, northern hemi- sphere polar vortex area index in October in the last year, Asia polar vortex strength index in November in the last year, north boundary of North America-At- lantic subtropical high in September in that year, north boundary of North Africa-At- lantic-North America subtropical high in January in that year, sunspot in September of the last year and eastern Pacific subtropical high area index in September in that year. [Conclusion] With the stepwise regression, the forecasting equations of the rice planthopper occurrence established based on the atmospheric circulation indices could be used for actual forecast.
基金Supported by Tianjin Aquatic Species Diveristy Surveying,Monitoring and Evaluation Proejct~~
文摘[Objective] The aim was to research macrobenthos community structure and its relations with environmental factors in three reservoirs. [Method] Benthic diversity and water quality of Yuqiao Reservoir, Beidagang Reservoir and Er- wangzhuang Reservoir were investigated in May, July and September 2011, respec- tively. []Result] Of all the 14 sampling sites, 22 species of macroinvertebrates were collected, totally, which included 6 species of aquatic insects, 7 species of Mollusca, 2 species of Crustacean, 7 species of Oligochaeta. The species of macroinverte- brates during May, July and September in Yuqiao reservoir were 11, 8 and 10, respectively. The dominant species were Chironomus sinicus, and Monopylephorus limosus. The average density and biomass of the macrobenthos were 132.43 ind./m2 and 50.09 g/m2. Yuqiao reservoir was mostly at status of premediate polluted, according to the Margalef index, Shannon index and Pielou index. The species of during May, July and September in Beidagang reservoir were 5 5 and 5, respectively. The dominant species were Chironomus sinicus, Penaeus vannamei. The average density and biomass of the macrobenthos were 218 ind./m2 and 2.70 g/m2. Beidagang reservoir was mostly at status of heavy polluted, accord- ing to the Margalef index, Shannon-wiener index, Pielou index. The species of during May, July and September in Erwangzhuang reservoir were 3, 5 and 5, respectively. The dominant species were Monopylephorus limosus, Chi- ronomus sinicus. The average density and biomass of the macrobenthos were 104 ind/m2 and 0.20 g/m2. Erwangzhuang reservoir was mostly at status of intermediate polluted, according to the Margalef index, Shannon index, Pielou index. The density of zoobenthos in Yuqiao Reservoir was positively significantly correlated with TP （P〉 0.05）, negatively correlated with NH4＋-N （P〉0.05）, positively correlated with COD （P〈 0.01）, not significantly correlated with other environment factors （P〉0.05）. There was no significant correlation between biomass of zoobenthos and environment factors. The density of zoobenthos in Beidagang Reservoir with NH4＋-N was positively signif- icantly correlated （P〈0.05）, not significantly correlated with other aquatic environment factors （P〉0.05）. There was no significant correlation between biomass of zoobenthos and environment factors. The density of zoobenthos in Erwangzhuang Reser- voir with NO3-N was positively significantly correlated （P〈0.05）, not significant cor- related with other aquatic environment factors （F〉0.05）. The biomass of zoobenthos in Erwangzhuang Reservoir with NH4＋-N was positively significantly correlated （P〈 0.05）, not significant correlated with other aquatic environment factors （P〉0.05）. [Conclusion] It is indicated that this three reservoirs were all eutrophied and polluted, and the eurephication extent change of water in three reservoirs is as follows： Beidagang reservoir〉Erwangzhuang reservoir〉Yuqiao reservoir.
文摘The local chaos characteristics of the time series pressure fluctuations of gas liquid two phase flow in a self aspirated reversed flow jet loop reactor are studied by the deterministic chaos analysis technique. It is found that the estimated local largest Lyapunov exponent is positive in all cases and the profile is similar to that of the local fractal dimension in this reactor. The positive largest Lyapunov exponent shows that the reactor is a nonlinear chaotic system. The obvious distribution indicates that the local nonlinear characteristic parameters such as the Lyapunov exponent and the fractal dimension could be applied to further study the flow characteristics such as the flow regine transitions and flow structures of the multi phase reactors.
文摘Hursts rescaled range (R/S) analysis and Wolfs attractor reconstruction technique have been adopted to estimate the local fractal dimensions and the local largest Lyapunov exponents in terms of the time series pressure fluctuations obtained from a gas liquid solid three phase self aspirated reversed flow jet loop reactor,respectively.The results indicate that the local fractal dimensions and the local largest Lyapunov exponents in both the jet region and the tubular region inside the draft tube increase with the increase in the jet liquid flowrates and the solid loadings,the local fractal dimension profiles are similar to those of the largest Lyapunov exponent,the local largest lyapunov exponents are positive for all cases,and the flow behavior of such a reactor is chaotic.The local nonlinear characteristic parameters such as the local fractal dimension and the local largest Lyapunov exponent could be applied to further study the flow properties such as the flow regime transitions and flow structures of this three phase jet loop reactor.
