Basic situation of the current ecological environment construction in land consolidation and rehabilitation of China is introduced. The related advanced experience abroad is summarized from mainly four aspects, namely...Basic situation of the current ecological environment construction in land consolidation and rehabilitation of China is introduced. The related advanced experience abroad is summarized from mainly four aspects, namely policy, system as well as subject development, planning guidance, design method of project planning and engineering study, and practical countermeasures to China's ecological environment construction in land reclamation are proposed. In terms of policy, system and subject, relevant regulations, policies and system construction should be strengthened and the framework of policy, system and subject development in ecological landscape construction of China's land reclamation should be proposed, integrating ecological environment construction into land reclamation. At the level of strategic planning, the spatial layout and construction key points of green infrastructure in land reclamation of "urban multi-functional developing region, eastern economic developed region, central modern agricultural region and northwestern ecological fragile region" should be achieved. At the level of project planning design, ecological principles, sustainable landscape design principles and vernacular landscape design methods are to be integrated into the planning procedure to form operable technique regulations or introductions. At the level of engineering design, engineering technique system, standards and regulations of ditches, roads, forests and channels with local distinctions should be formulated according to the characters and strategic demands of urbanization, industrialization, agriculture modernization and ecological environment preservation in different regions.展开更多
Lithium niobate(LiNbO_(3),LN)crystal is a multi-functional material with favorable piezoelectric,nonlinear optical and electro-optic properties.In this study,the electromechanical properties of the radial extensional(...Lithium niobate(LiNbO_(3),LN)crystal is a multi-functional material with favorable piezoelectric,nonlinear optical and electro-optic properties.In this study,the electromechanical properties of the radial extensional(RE)and the thickness extensional(TE)modes of the congruent LN are studied and the temperature dependent behaviors are revealed.The RE mode electromechanical coupling factors(kp)for the Y-and Z-oriented discs are calculated and found to be 3.8%and 24.7%,respectively,which are nearly the same as the experimental results of 3.8%and 25.2%,respectively.The maximum RE and thickness shear(TS)modes electromechanical coupling factors are obtained to be 47.6%and 68.5%for the Yx/25and Yx/167crystal cuts,respectively.The LN crystal possesses good temperature stability of the electromechanical coupling factors(RE and TE modes)from 20℃ to 500℃,where the variations of kp and kt for the Y-oriented discs are<8.0%and<1.8%,respectively.展开更多
Despite signifcant advances in the phylogenomics of bivalves over the past decade,the higher-level phylogeny of Imparidentia(a superorder of Heterodonta)remains elusive.Here,a total of fve new mitochondrial sequences(...Despite signifcant advances in the phylogenomics of bivalves over the past decade,the higher-level phylogeny of Imparidentia(a superorder of Heterodonta)remains elusive.Here,a total of fve new mitochondrial sequences(Chama asperella,Chama limbula,Chama dunkeri,Barnea manilensis and Ctena divergens)was added to provide resolution in nodes that required additional study.Although the monophyly of Lucinida remains less clear,the results revealed the overall backbone of the Imparidentia tree and the monophyly of Imparidentia.Likewise,most relationships among the fve major Imparidentia lineages—Lucinida,Cardiida,Adapedonta,Myida and Venerida—were addressed with a well-supported topology.Basal relationships of Imparidentia recovered Lucinidae as the sister group to all remaining imparidentian taxa.Thyasiridae is a sister group to other imparidentian bivalves(except Lucinidae species)which is split into Cardiida,Adapedonta and the divergent clade of Neoheterodontei.Neoheterodontei was comprised of Venerida and Myida,the former of which now also contains Chamidae as the sister group to all the remaining venerid taxa.Moreover,molecular divergence times were inferred by calibrating nine nodes in the Imparidentia tree of life by extinct taxa.The origin of these major clades ranged from Ordovician to Permian with the diversifcation through the Palaeozoic to Mesozoic.Overall,the results obtained in this study demonstrate a better-resolved Imparidentia phylogeny based on mitochondrial genomes.展开更多
文摘Basic situation of the current ecological environment construction in land consolidation and rehabilitation of China is introduced. The related advanced experience abroad is summarized from mainly four aspects, namely policy, system as well as subject development, planning guidance, design method of project planning and engineering study, and practical countermeasures to China's ecological environment construction in land reclamation are proposed. In terms of policy, system and subject, relevant regulations, policies and system construction should be strengthened and the framework of policy, system and subject development in ecological landscape construction of China's land reclamation should be proposed, integrating ecological environment construction into land reclamation. At the level of strategic planning, the spatial layout and construction key points of green infrastructure in land reclamation of "urban multi-functional developing region, eastern economic developed region, central modern agricultural region and northwestern ecological fragile region" should be achieved. At the level of project planning design, ecological principles, sustainable landscape design principles and vernacular landscape design methods are to be integrated into the planning procedure to form operable technique regulations or introductions. At the level of engineering design, engineering technique system, standards and regulations of ditches, roads, forests and channels with local distinctions should be formulated according to the characters and strategic demands of urbanization, industrialization, agriculture modernization and ecological environment preservation in different regions.
基金the Primary Research&Development Plan of Shandong Province(2017CXGC0413)the National Natural Science Foundation of China(Grant No.51872165).
文摘Lithium niobate(LiNbO_(3),LN)crystal is a multi-functional material with favorable piezoelectric,nonlinear optical and electro-optic properties.In this study,the electromechanical properties of the radial extensional(RE)and the thickness extensional(TE)modes of the congruent LN are studied and the temperature dependent behaviors are revealed.The RE mode electromechanical coupling factors(kp)for the Y-and Z-oriented discs are calculated and found to be 3.8%and 24.7%,respectively,which are nearly the same as the experimental results of 3.8%and 25.2%,respectively.The maximum RE and thickness shear(TS)modes electromechanical coupling factors are obtained to be 47.6%and 68.5%for the Yx/25and Yx/167crystal cuts,respectively.The LN crystal possesses good temperature stability of the electromechanical coupling factors(RE and TE modes)from 20℃ to 500℃,where the variations of kp and kt for the Y-oriented discs are<8.0%and<1.8%,respectively.
基金The authors would like to thank Dr.Weibo Song and Ms.Gongaote Zhang for improving the quality of the fgures in the manuscript.This work was supported by the grants from National Natural Science Foundation of China(31972789)Industrial Development Project of Qingdao City(20-3-4-16-nsh)the Science and Technology Development Project of Weihai City(2018NS01).
文摘Despite signifcant advances in the phylogenomics of bivalves over the past decade,the higher-level phylogeny of Imparidentia(a superorder of Heterodonta)remains elusive.Here,a total of fve new mitochondrial sequences(Chama asperella,Chama limbula,Chama dunkeri,Barnea manilensis and Ctena divergens)was added to provide resolution in nodes that required additional study.Although the monophyly of Lucinida remains less clear,the results revealed the overall backbone of the Imparidentia tree and the monophyly of Imparidentia.Likewise,most relationships among the fve major Imparidentia lineages—Lucinida,Cardiida,Adapedonta,Myida and Venerida—were addressed with a well-supported topology.Basal relationships of Imparidentia recovered Lucinidae as the sister group to all remaining imparidentian taxa.Thyasiridae is a sister group to other imparidentian bivalves(except Lucinidae species)which is split into Cardiida,Adapedonta and the divergent clade of Neoheterodontei.Neoheterodontei was comprised of Venerida and Myida,the former of which now also contains Chamidae as the sister group to all the remaining venerid taxa.Moreover,molecular divergence times were inferred by calibrating nine nodes in the Imparidentia tree of life by extinct taxa.The origin of these major clades ranged from Ordovician to Permian with the diversifcation through the Palaeozoic to Mesozoic.Overall,the results obtained in this study demonstrate a better-resolved Imparidentia phylogeny based on mitochondrial genomes.
