本文对容性支节加载的小型化超表面天线进行了分析与设计.通过在方形贴片上引入一对容性负载支节,可以有效地降低超表面单元的工作频率,从而将传统方形贴片超表面单元的尺寸减小55%.在单元设计的基础上,设计了一款4×4阵列的超表面...本文对容性支节加载的小型化超表面天线进行了分析与设计.通过在方形贴片上引入一对容性负载支节,可以有效地降低超表面单元的工作频率,从而将传统方形贴片超表面单元的尺寸减小55%.在单元设计的基础上,设计了一款4×4阵列的超表面天线,并采用特征模分析(CMA)解释了超表面天线的辐射机制.为了验证设计思路,对天线进行了加工和测试,测量的-10 d B阻抗带宽为21. 7%,并在工作频带内保持6 d Bi的辐射增益.展开更多
Ionic liquid(IL),1-butyl-3-methylimidazolium hexafluorophosphate([BMIM]PF6)as a new and environmentally friendly diluent was introduced to prepare poly(vinylidene fluoride)(PVDF)membranes via thermally induced phase s...Ionic liquid(IL),1-butyl-3-methylimidazolium hexafluorophosphate([BMIM]PF6)as a new and environmentally friendly diluent was introduced to prepare poly(vinylidene fluoride)(PVDF)membranes via thermally induced phase separation(TIPS).Phase diagram of PVDF/[BMIM]PF6 was measured.The effects of polymer concentration and quenching temperature on the morphologies,properties,and performances of the PVDF membranes were investigated.When the polymer concentration was 15 wt%,the pure water flux of the fabricated membrane was up to nearly 2000 L·m-2·h-1,along with adequate mechanical strength.With the increasing of PVDF concentration and quenching temperature,mean pore size and water permeability of the membrane decreased.SEM results showed that PVDF membranes manufactured by ionic liquid(BMIm PF6)presented spherulite structure.And the PVDF membranes were represented asβphase by XRD and FTIR characterization.It provides a new way to prepare PVDF membranes with piezoelectric properties.展开更多
The species composition of plant communities is determined by a number of factors,including current environmental conditions as well as biogeographical and evolutionary history.Despite evidence that plant diversity de...The species composition of plant communities is determined by a number of factors,including current environmental conditions as well as biogeographical and evolutionary history.Despite evidence that plant diversity decreases and species relatedness increases along latitudinal and environmental gradients(e.g.,low temperatures),it remains unclear whether these same patterns occur along elevational gradients,especially in the subtropical mountainous areas harboring rich biodiversity.In this study,we explored the pattern of phylogenetic relatedness of woody angiosperm assemblages and examined the effects of temperature variables on the phylogenetic relatedness among angiosperm woody plants using generalized linear model in subtropical forest communities along a broad elevational gradient in the Dulong Valley of Yunnan Province,China.Our results showed that woody angiosperm species in local forest plots tend to be more phylogenetically related at higher elevations and in areas with lower temperatures.Additionally,winter average temperature,rather than mean annual temperature,is a major predictor of the pattern of increasing phylogenetic relatedness with increasing elevation.This finding is consistent with the prediction of‘Tropical Niche Conservatism’hypothesis,which highlights the role of niche constraints in driving phylogenetic community assembly along an elevational gradient.展开更多
文摘本文对容性支节加载的小型化超表面天线进行了分析与设计.通过在方形贴片上引入一对容性负载支节,可以有效地降低超表面单元的工作频率,从而将传统方形贴片超表面单元的尺寸减小55%.在单元设计的基础上,设计了一款4×4阵列的超表面天线,并采用特征模分析(CMA)解释了超表面天线的辐射机制.为了验证设计思路,对天线进行了加工和测试,测量的-10 d B阻抗带宽为21. 7%,并在工作频带内保持6 d Bi的辐射增益.
基金the financial support of the National Natural Science Foundation of China(Grant No.21606125)the Natural Science Foundation of Jiangsu Province(Grant No.BK20160984)+3 种基金the National Key R&D Program of China(Grant No.2017YFC0403702)the Materials-Oriented Chemical Engineering State Key Laboratory Program(KL16-09)the open project program of Jiangsu Key Lab for Chemistry of Low-Dimensional Materials(JSKC17005)the Priority Academic Program Development of Jiangsu Higher Education Institution(PAPD)。
文摘Ionic liquid(IL),1-butyl-3-methylimidazolium hexafluorophosphate([BMIM]PF6)as a new and environmentally friendly diluent was introduced to prepare poly(vinylidene fluoride)(PVDF)membranes via thermally induced phase separation(TIPS).Phase diagram of PVDF/[BMIM]PF6 was measured.The effects of polymer concentration and quenching temperature on the morphologies,properties,and performances of the PVDF membranes were investigated.When the polymer concentration was 15 wt%,the pure water flux of the fabricated membrane was up to nearly 2000 L·m-2·h-1,along with adequate mechanical strength.With the increasing of PVDF concentration and quenching temperature,mean pore size and water permeability of the membrane decreased.SEM results showed that PVDF membranes manufactured by ionic liquid(BMIm PF6)presented spherulite structure.And the PVDF membranes were represented asβphase by XRD and FTIR characterization.It provides a new way to prepare PVDF membranes with piezoelectric properties.
基金This study was supported by the National Natural Science Foundation of China(grant nos.31770228,31570212,31370243)the Belt and Road Project of West Light Foundation of the Chinese Academy of Sciences,Yunnan Science and Technology Innovation Team Program(grant no.2019HC015)+1 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(grant no.2019QZKK0502)the Biodiversity Survey and Assessment Project of the Ministry of Ecology and Environment,The People’s Republic of China,China(grant no.2019HJ2096001006).
文摘The species composition of plant communities is determined by a number of factors,including current environmental conditions as well as biogeographical and evolutionary history.Despite evidence that plant diversity decreases and species relatedness increases along latitudinal and environmental gradients(e.g.,low temperatures),it remains unclear whether these same patterns occur along elevational gradients,especially in the subtropical mountainous areas harboring rich biodiversity.In this study,we explored the pattern of phylogenetic relatedness of woody angiosperm assemblages and examined the effects of temperature variables on the phylogenetic relatedness among angiosperm woody plants using generalized linear model in subtropical forest communities along a broad elevational gradient in the Dulong Valley of Yunnan Province,China.Our results showed that woody angiosperm species in local forest plots tend to be more phylogenetically related at higher elevations and in areas with lower temperatures.Additionally,winter average temperature,rather than mean annual temperature,is a major predictor of the pattern of increasing phylogenetic relatedness with increasing elevation.This finding is consistent with the prediction of‘Tropical Niche Conservatism’hypothesis,which highlights the role of niche constraints in driving phylogenetic community assembly along an elevational gradient.
