Two japonica rice varieties, Longjing 20 (more tillers and curved panicle type, MCP) and Longjing 21 (few tillers and half erect panicle type, FEP), were used to study the effects of row-spacing on canopy structure, m...Two japonica rice varieties, Longjing 20 (more tillers and curved panicle type, MCP) and Longjing 21 (few tillers and half erect panicle type, FEP), were used to study the effects of row-spacing on canopy structure, morphological characteristics and yield. The results showed that the percentage of productive tiller reduced first, and increased afterwards as row-spacing increasing. The relationship between row spacing and the percentage of productive tiller fitted a quadratic regression. The effects of row spacing on leaf area index (LAI) at later tillering stage and the highest stem number per square meter also followed a quadratic regression relationship with increasing first and then reducing. The effects of row-spacing on primary branch were larger than the secondary branch in Longjing 20. However, the trend in Longjing 21 was opposite. The relationship between row spacing and seed setting rate of the secondary branch or panicle was negatively correlated. An extreme significant negative correlation was obtained between seed setting rate of secondary branch in Longjing 20. There was no significant positive correlation between row-spacing and yield in Longjing 20 (R2=0.68). However, the negative correlation between row-spacing and yield of Longjing 21 was extremely significant (R2=-0.96**). The canopy structure of MCP was more sensitive to row-spacing. The positive correlation between row spacing and the length of the flag leaf (R2=0.89**), the width of the flag leaf (R2=0.85*), the length of the last internode (R2=0.85*), the length of the last 2nd internode (R2=0.96**) or the length of the panicle (R2=0.91**) was significant or extremely significant in Longjing 20, but not in Longjing 21. The wider row-spacing promoted the accumulation of the dry matter of panicle, stem and leaf and the yield formation in MCP. The best row-spacing in Longjing 20 was 30 cm. For Longjing 21, the narrower row-spacing was better. The best row-spacing of it was 21 cm. These results suggested that improved the population environment of MCP or the utilization of the free space in the field of FEP could be reached either by wider row-spacing or narrow row-spacing.展开更多
Discussions pertaining to enhancement in the luminous efficiency of cesium iodide(CsI)detectors doped with sodium(Na)abound.In this study,the defect structure of one Cs atom replaced by one Na atom is calculated using...Discussions pertaining to enhancement in the luminous efficiency of cesium iodide(CsI)detectors doped with sodium(Na)abound.In this study,the defect structure of one Cs atom replaced by one Na atom is calculated using the ab initio method.Subsequently,the electronic band structures,densities of states,optical absorption spectra,phonons,and transport properties of CsI in perfect and defective structures are investigated.The absorption spectra of CsI with and without Na impurities are compared.It is discovered that the impurity levels in the forbidden band are generated from the shell electron distributions of the impurity atoms,not from lattice distortions.Furthermore,it is discovered that the optical absorption can be enhanced by doping CsI with Na.展开更多
通过基于电子学取数的测试系统,在地磁场环境对两种不同聚焦级结构的微通道板型光电倍增管(microchannel plate type photomultiplier tubes,MCP-PMT)进行了各项性能测试,例如单光电子谱、后脉冲、渡越时间涨落、信号上升下降时间、收...通过基于电子学取数的测试系统,在地磁场环境对两种不同聚焦级结构的微通道板型光电倍增管(microchannel plate type photomultiplier tubes,MCP-PMT)进行了各项性能测试,例如单光电子谱、后脉冲、渡越时间涨落、信号上升下降时间、收集效率等。并通过改变光电倍增管与地磁场的相对位置,测得不同角度下MCP-PMT的性能,并且经对比屏蔽磁场条件下与地磁场环境下MCP-PMT的性能,定性分析了地磁场对MCP-PMT的性能影响。展开更多
针对结构振动与电磁驱动AM D控制系统(以下简称EM D系统)的相互作用问题,提出了是否考虑、以及考虑何种程度相互作用的三种理论计算模型并进行了试验研究。首先试验比较了EM D系统在正弦扫频控制电压输入下各阶理论模型预测结果与试验...针对结构振动与电磁驱动AM D控制系统(以下简称EM D系统)的相互作用问题,提出了是否考虑、以及考虑何种程度相互作用的三种理论计算模型并进行了试验研究。首先试验比较了EM D系统在正弦扫频控制电压输入下各阶理论模型预测结果与试验结果的差异,验证了各模型对系统的描述精度;其次以E l C en tro地震波输入为例,试验比较了3种计算模型在3种控制算法共9种试验工况下,EM D控制系统对结构地震响应控制效果的影响。本文所有试验结果均表明只有考虑相互作用、并且充分考虑高阶相互作用才能最佳地描述EM D控制系统在结构中真实的工作状态,才能充分发挥EM D系统对结构振动的控制作用,从而为实现高性能的结构振动主动控制试验与应用奠定基础。展开更多
基金Supported by the National Key Technology R&D Program (2007BAD65B01-4)Science and Technology Development Plan of Heilongjiang Province in China (GB06B104-1-5)Key Technology R&D Program of Heilongjiang Province in China (GA09B102-3)
文摘Two japonica rice varieties, Longjing 20 (more tillers and curved panicle type, MCP) and Longjing 21 (few tillers and half erect panicle type, FEP), were used to study the effects of row-spacing on canopy structure, morphological characteristics and yield. The results showed that the percentage of productive tiller reduced first, and increased afterwards as row-spacing increasing. The relationship between row spacing and the percentage of productive tiller fitted a quadratic regression. The effects of row spacing on leaf area index (LAI) at later tillering stage and the highest stem number per square meter also followed a quadratic regression relationship with increasing first and then reducing. The effects of row-spacing on primary branch were larger than the secondary branch in Longjing 20. However, the trend in Longjing 21 was opposite. The relationship between row spacing and seed setting rate of the secondary branch or panicle was negatively correlated. An extreme significant negative correlation was obtained between seed setting rate of secondary branch in Longjing 20. There was no significant positive correlation between row-spacing and yield in Longjing 20 (R2=0.68). However, the negative correlation between row-spacing and yield of Longjing 21 was extremely significant (R2=-0.96**). The canopy structure of MCP was more sensitive to row-spacing. The positive correlation between row spacing and the length of the flag leaf (R2=0.89**), the width of the flag leaf (R2=0.85*), the length of the last internode (R2=0.85*), the length of the last 2nd internode (R2=0.96**) or the length of the panicle (R2=0.91**) was significant or extremely significant in Longjing 20, but not in Longjing 21. The wider row-spacing promoted the accumulation of the dry matter of panicle, stem and leaf and the yield formation in MCP. The best row-spacing in Longjing 20 was 30 cm. For Longjing 21, the narrower row-spacing was better. The best row-spacing of it was 21 cm. These results suggested that improved the population environment of MCP or the utilization of the free space in the field of FEP could be reached either by wider row-spacing or narrow row-spacing.
基金supported by the National Natural Science Foundation of China (Nos. 12135004, 11635003, 11961141004, and 11875088)
文摘Discussions pertaining to enhancement in the luminous efficiency of cesium iodide(CsI)detectors doped with sodium(Na)abound.In this study,the defect structure of one Cs atom replaced by one Na atom is calculated using the ab initio method.Subsequently,the electronic band structures,densities of states,optical absorption spectra,phonons,and transport properties of CsI in perfect and defective structures are investigated.The absorption spectra of CsI with and without Na impurities are compared.It is discovered that the impurity levels in the forbidden band are generated from the shell electron distributions of the impurity atoms,not from lattice distortions.Furthermore,it is discovered that the optical absorption can be enhanced by doping CsI with Na.
文摘通过基于电子学取数的测试系统,在地磁场环境对两种不同聚焦级结构的微通道板型光电倍增管(microchannel plate type photomultiplier tubes,MCP-PMT)进行了各项性能测试,例如单光电子谱、后脉冲、渡越时间涨落、信号上升下降时间、收集效率等。并通过改变光电倍增管与地磁场的相对位置,测得不同角度下MCP-PMT的性能,并且经对比屏蔽磁场条件下与地磁场环境下MCP-PMT的性能,定性分析了地磁场对MCP-PMT的性能影响。
文摘针对结构振动与电磁驱动AM D控制系统(以下简称EM D系统)的相互作用问题,提出了是否考虑、以及考虑何种程度相互作用的三种理论计算模型并进行了试验研究。首先试验比较了EM D系统在正弦扫频控制电压输入下各阶理论模型预测结果与试验结果的差异,验证了各模型对系统的描述精度;其次以E l C en tro地震波输入为例,试验比较了3种计算模型在3种控制算法共9种试验工况下,EM D控制系统对结构地震响应控制效果的影响。本文所有试验结果均表明只有考虑相互作用、并且充分考虑高阶相互作用才能最佳地描述EM D控制系统在结构中真实的工作状态,才能充分发挥EM D系统对结构振动的控制作用,从而为实现高性能的结构振动主动控制试验与应用奠定基础。
