The Badain Jaran Desert,located in the Alxa Plateau,Northwest China,features mega-dunes and a unique dune-lake alternation landscape.This paper presented the aeolian sediment structures of three representative dunes i...The Badain Jaran Desert,located in the Alxa Plateau,Northwest China,features mega-dunes and a unique dune-lake alternation landscape.This paper presented the aeolian sediment structures of three representative dunes in the Badain Jaran Desert using ground-penetrating radar (GPR).We processed and analyzed the GPR data and investigated the feasibility of using integrated GPR and sedimentological data to reconstruct dunes structure,sedimentary environment and geomorphological evolution.The results show that the internal structures of star dune and transverse dune represent various stages of mega-dune evolution: the main deposition processes of mega-dune are similar to those of transverse dunes but have a more complicated mechanism of sand transport and deposition because of the superimposition of dunes;the upper section of the mega-dune has a structure similar to that of star dune,with vertical aggradations on top.Diffraction hyperbolae in the GPR profile indicates that the presence of ancient dunes characterized by calcareous cementation layers is involved in the maintenance of mega-dunes,and water levels,shown by continuous,sub-horizontal GPR reflections,are supposed to be closely related to mega-dunes and the interdune lakes.Outcrop of wet sand and horizontal stratifications on the GPR image indicate moisture potentials with different levels inside mega-dunes.The multiplex geomorphology in the Badain Jaran Desert is the result of global climatic undulation,the unique geographical location,the geological structural features,etc.展开更多
Some well-preserved conifer leafy shoots and female cones from the Lower Cretaceous Changcai For- mation near Fudong of Helong, eastern Jilin, Northeast China are studied. Based on gross morphological and cuticular st...Some well-preserved conifer leafy shoots and female cones from the Lower Cretaceous Changcai For- mation near Fudong of Helong, eastern Jilin, Northeast China are studied. Based on gross morphological and cuticular study, a new species, Elatides helongensis Sun et Zhao （ sp. nov. ） is described systematically. The new species is characterized by persistent, linear or slightly falcate leaves with obtusely acute apex, attached helically on the shoots. Female cones of the new species are terminal and oval, composed of persistent helically- arranged rhomboidal scales and erect seeds. One erect seed is growing on each scale. Leaf cuticles are hyposto- matic. Monocylic stomata are ellipse, composed of 2 sunken guard ceils and 4-8 subsidiary cells. Moreover, the cuticles of a young female cone of Pityostrobus yingchengensis Yang are described for the first time.展开更多
The urban and rural integration is a new stage of city development, which is a process of urban and rural mutual supplementary integration, collaborative development and mutual prosperity. It takes the industry and ag...The urban and rural integration is a new stage of city development, which is a process of urban and rural mutual supplementary integration, collaborative development and mutual prosperity. It takes the industry and agriculture, city and countryside as a whole, with overall planning and coordination development, through system innovation and policy adjustment, in order to realize the integration development of urban and rural planning construction, industrial development, infrastructure, ecological environment and social career. This paper conducts the empirical analysis on the urban and rural integration construction development of Changji City of Changji Region in Xinjiang, studying the existing problems and restrictive factors of the process in promoting urban and rural integration construction in western region of China and trying to propose the corresponding countermeasures.展开更多
基金Under the auspices of National Natural Science Foundation of China (No.50879033,41001116)Specialized Research Fund for the Doctoral Program of Higher Education (No.20090211110025)Fundamental Research Funds for the Central Universities (No.lzujbky-2010-221)
文摘The Badain Jaran Desert,located in the Alxa Plateau,Northwest China,features mega-dunes and a unique dune-lake alternation landscape.This paper presented the aeolian sediment structures of three representative dunes in the Badain Jaran Desert using ground-penetrating radar (GPR).We processed and analyzed the GPR data and investigated the feasibility of using integrated GPR and sedimentological data to reconstruct dunes structure,sedimentary environment and geomorphological evolution.The results show that the internal structures of star dune and transverse dune represent various stages of mega-dune evolution: the main deposition processes of mega-dune are similar to those of transverse dunes but have a more complicated mechanism of sand transport and deposition because of the superimposition of dunes;the upper section of the mega-dune has a structure similar to that of star dune,with vertical aggradations on top.Diffraction hyperbolae in the GPR profile indicates that the presence of ancient dunes characterized by calcareous cementation layers is involved in the maintenance of mega-dunes,and water levels,shown by continuous,sub-horizontal GPR reflections,are supposed to be closely related to mega-dunes and the interdune lakes.Outcrop of wet sand and horizontal stratifications on the GPR image indicate moisture potentials with different levels inside mega-dunes.The multiplex geomorphology in the Badain Jaran Desert is the result of global climatic undulation,the unique geographical location,the geological structural features,etc.
基金supported by the Natural Science Foundation of China (No.30670138,31270277)
文摘Some well-preserved conifer leafy shoots and female cones from the Lower Cretaceous Changcai For- mation near Fudong of Helong, eastern Jilin, Northeast China are studied. Based on gross morphological and cuticular study, a new species, Elatides helongensis Sun et Zhao （ sp. nov. ） is described systematically. The new species is characterized by persistent, linear or slightly falcate leaves with obtusely acute apex, attached helically on the shoots. Female cones of the new species are terminal and oval, composed of persistent helically- arranged rhomboidal scales and erect seeds. One erect seed is growing on each scale. Leaf cuticles are hyposto- matic. Monocylic stomata are ellipse, composed of 2 sunken guard ceils and 4-8 subsidiary cells. Moreover, the cuticles of a young female cone of Pityostrobus yingchengensis Yang are described for the first time.
文摘The urban and rural integration is a new stage of city development, which is a process of urban and rural mutual supplementary integration, collaborative development and mutual prosperity. It takes the industry and agriculture, city and countryside as a whole, with overall planning and coordination development, through system innovation and policy adjustment, in order to realize the integration development of urban and rural planning construction, industrial development, infrastructure, ecological environment and social career. This paper conducts the empirical analysis on the urban and rural integration construction development of Changji City of Changji Region in Xinjiang, studying the existing problems and restrictive factors of the process in promoting urban and rural integration construction in western region of China and trying to propose the corresponding countermeasures.
