The Qilian Mountain permafrost area located in the northern of Qinghai-Tibet Plateau is a favorable place for natural gas hydrate formation and enrichment,due to its well-developed fractures and abundant gas sources.U...The Qilian Mountain permafrost area located in the northern of Qinghai-Tibet Plateau is a favorable place for natural gas hydrate formation and enrichment,due to its well-developed fractures and abundant gas sources.Understanding the formation and distribution of multi-component gas hydrates in fractures is crucial in accurately evaluating the hydrate reservoir resources in this area.The hydrate formation experiments were carried out using the core samples drilled from hydrate-bearing sediments in Qilian Mountain permafrost area and the multi-component gas with similar composition to natural gas hydrates in Qilian Mountain permafrost area.The formation and distribution characteristics of multi-component gas hydrates in core samples were observed in situ by X-ray Computed Tomography(X-CT)under high pressure and low temperature conditions.Results show that hydrates are mainly formed and distributed in the fractures with good connectivity.The ratios of volume of hydrates formed in fractures to the volume of fractures are about 96.8%and 60.67%in two different core samples.This indicates that the fracture surface may act as a favorable reaction site for hydrate formation in core samples.Based on the field geological data and the experimental results,it is preliminarily estimated that the inventory of methane stored in the fractured gas hydrate in Qilian Mountain permafrost area is about 8.67×1013 m3,with a resource abundance of 8.67×108 m3/km2.This study demonstrates the great resource potential of fractured gas hydrate and also provides a new way to further understand the prospect of natural gas hydrate and other oil and gas resources in Qilian Mountain permafrost area.展开更多
Grain production core area is key region of modern agricultural development in China. Through summarizing related literature about grain production area and modern agricultural development researches both at home and ...Grain production core area is key region of modern agricultural development in China. Through summarizing related literature about grain production area and modern agricultural development researches both at home and abroad,it obtained characteristics and existing problems in the modern agricultural development of the grain production core area. It is found that there are many research perspectives in modern agricultural development of the grain production core area. On the basis of analyzing the grain production core area and connotation,mode and evaluation of the modern agricultural development,it is concluded that further study should be carried out for adopting which development mode and how to make evaluation,so as to provide theoretical guidance for balanced development of modern agriculture in grain production core area of different regions.展开更多
Objective:To study the changes of nitric oxide synthase(NOS)activity in penumbral and core area during focal cerebral ischemia and reperfusion,and to explore the therapeutic window of focal cerebral ischemia. Methods...Objective:To study the changes of nitric oxide synthase(NOS)activity in penumbral and core area during focal cerebral ischemia and reperfusion,and to explore the therapeutic window of focal cerebral ischemia. Methods:The middle cerebral artery of rats was occluded for 15,30,60,90 and 120 min by an intraluminal filament respectively,and recirculation was instituted for 24 h.The changes of NOS activity in ischemic core area(parietal cortex and caudoputamen)and penumbral area (frontal cortex)were examined after focal cerebral ischemia and reperfusion using NADPH-d histochemistry technique.Results:The NOS activity of the ischemic penumbral area peaked at 60 min while the ischemic core area peaked at 30 min then declined at 90-120 min sharply.Conclusion:NOS takes part in cerebral ischemic damage during focal cerebral ischemia and reperfusion.The NOS activity of the ischemic penumbral area is different from the ischemic core area.The peak time of the penumbral area is delayed comparing with the core area.The data suggest that the best time to apply NOS inhibitor is within 30 min in ischemic core area, and 60 min in penumbral area.展开更多
Urban planning is a process of government as planner to purposefully manage and intervene in the urban development. In this paper,five major tasks for the construction of an international language environment in the c...Urban planning is a process of government as planner to purposefully manage and intervene in the urban development. In this paper,five major tasks for the construction of an international language environment in the core urban areas are proposed from the perspective of urban planning:to explore an effective working mechanism for the construction of the international language environment;to improve the ability of citizens in foreign language communication;to standardize public bilingual notices and signs marking system;to innovate the internationalized operational models of the key industries;to create a multi-functional foreign language consulting service system. Thereby,the objective to improve the international language environment and competitiveness of the urban areas can be accomplished.展开更多
Studying the urban landscape pattern plays a crucial role in scientific land use and management and in improving the urban ecological environment. In this paper, Auto CAD, Arc GIS, Fragstats, and other software were u...Studying the urban landscape pattern plays a crucial role in scientific land use and management and in improving the urban ecological environment. In this paper, Auto CAD, Arc GIS, Fragstats, and other software were used to analyze the data of the fourth phase of land use in the core area of Yangling Demonstration Zone. The results showed that:(1) in the core area, the percentage of construction land increased from 18.22% to 61.72%, and the percentage of agricultural land decreased from 58.36% to 11.14%. And the farm land was fragmented, and traffic connectivity was strengthened. The area of garden land was reduced from 251.89 hm2 to 50.38 hm2, and the landscape metric of forest land showed an inverted V-shaped curve.(2) The year 2009 in four phases witnessed the greatest landscape fragmentation, both Edge Density(ED) and Largest Patch Index(LPI) increased, and human interference enhanced the overall landscape complexity. Measures were formulated in terms of clear development goals, optimized al ocation of land resources, effective protection of ecological red lines, and definite ecological responsibility, so as to optimize the urban landscape pattern.展开更多
地理学研究可持续发展旨在构建人与自然命运共同体,实现人类社会的永续发展.该文依托CNKI数据库、读秀资源库以及Web of Science数据库,限定主题词为“可持续”“可持续发展”和“可持续性”,采用CiteSpace软件对1994—2021年中国地理...地理学研究可持续发展旨在构建人与自然命运共同体,实现人类社会的永续发展.该文依托CNKI数据库、读秀资源库以及Web of Science数据库,限定主题词为“可持续”“可持续发展”和“可持续性”,采用CiteSpace软件对1994—2021年中国地理学者“可持续”研究的核心力量、重点区域与重要领域进行文献计量分析,结果表明:1)中国地理学者“可持续”研究的过程可分为快速兴起(1994—2001年)、稳定发展(2002—2011年)和整固深化(2012—2021年)三个阶段.2)中国开展“可持续”研究的地理学者多达624位,主要是自然地理学者和人文地理学者,研究机构多达258个,主要是中国科学院所属地理单位,机构间合作具有空间邻近性,机构空间分布具有东、中、西梯度分异性;中国地理学者“可持续”研究的对象区域以地方行政区域为主,服务国家重大区域发展战略的特色鲜明.3)中国地理学者“可持续”研究的重点领域有资源可持续利用、生态环境保护与建设、农业可持续发展、旅游可持续发展、可持续发展教育、可持续发展伦理、消除贫困与可持续生计、区域人地关系协调、城市可持续发展、农村可持续发展、区域可持续发展战略、区域可持续发展评价等.4)未来中国地理学者的“可持续”研究应在可持续发展专业人才培养、可持续发展理论体系完善、可持续发展研究领域拓展、可持续发展服务能力提升等方面下功夫.展开更多
基金the financial support of the National Natural Science Foundation of China(42176212,41976074 and 41302034)the Marine S&T Fund of Shandong Province for Laoshan Laboratory(2021QNLM020002)the Marine Geological Survey Program(DD20221704)。
文摘The Qilian Mountain permafrost area located in the northern of Qinghai-Tibet Plateau is a favorable place for natural gas hydrate formation and enrichment,due to its well-developed fractures and abundant gas sources.Understanding the formation and distribution of multi-component gas hydrates in fractures is crucial in accurately evaluating the hydrate reservoir resources in this area.The hydrate formation experiments were carried out using the core samples drilled from hydrate-bearing sediments in Qilian Mountain permafrost area and the multi-component gas with similar composition to natural gas hydrates in Qilian Mountain permafrost area.The formation and distribution characteristics of multi-component gas hydrates in core samples were observed in situ by X-ray Computed Tomography(X-CT)under high pressure and low temperature conditions.Results show that hydrates are mainly formed and distributed in the fractures with good connectivity.The ratios of volume of hydrates formed in fractures to the volume of fractures are about 96.8%and 60.67%in two different core samples.This indicates that the fracture surface may act as a favorable reaction site for hydrate formation in core samples.Based on the field geological data and the experimental results,it is preliminarily estimated that the inventory of methane stored in the fractured gas hydrate in Qilian Mountain permafrost area is about 8.67×1013 m3,with a resource abundance of 8.67×108 m3/km2.This study demonstrates the great resource potential of fractured gas hydrate and also provides a new way to further understand the prospect of natural gas hydrate and other oil and gas resources in Qilian Mountain permafrost area.
文摘Grain production core area is key region of modern agricultural development in China. Through summarizing related literature about grain production area and modern agricultural development researches both at home and abroad,it obtained characteristics and existing problems in the modern agricultural development of the grain production core area. It is found that there are many research perspectives in modern agricultural development of the grain production core area. On the basis of analyzing the grain production core area and connotation,mode and evaluation of the modern agricultural development,it is concluded that further study should be carried out for adopting which development mode and how to make evaluation,so as to provide theoretical guidance for balanced development of modern agriculture in grain production core area of different regions.
文摘Objective:To study the changes of nitric oxide synthase(NOS)activity in penumbral and core area during focal cerebral ischemia and reperfusion,and to explore the therapeutic window of focal cerebral ischemia. Methods:The middle cerebral artery of rats was occluded for 15,30,60,90 and 120 min by an intraluminal filament respectively,and recirculation was instituted for 24 h.The changes of NOS activity in ischemic core area(parietal cortex and caudoputamen)and penumbral area (frontal cortex)were examined after focal cerebral ischemia and reperfusion using NADPH-d histochemistry technique.Results:The NOS activity of the ischemic penumbral area peaked at 60 min while the ischemic core area peaked at 30 min then declined at 90-120 min sharply.Conclusion:NOS takes part in cerebral ischemic damage during focal cerebral ischemia and reperfusion.The NOS activity of the ischemic penumbral area is different from the ischemic core area.The peak time of the penumbral area is delayed comparing with the core area.The data suggest that the best time to apply NOS inhibitor is within 30 min in ischemic core area, and 60 min in penumbral area.
基金The Philosophy and Social Science Planning Project of Henan Province(No.2013BYY013)the Key Humanities and Social Science Project of the Educational Department of Henan Province(No.2010-ZD 021)
文摘Urban planning is a process of government as planner to purposefully manage and intervene in the urban development. In this paper,five major tasks for the construction of an international language environment in the core urban areas are proposed from the perspective of urban planning:to explore an effective working mechanism for the construction of the international language environment;to improve the ability of citizens in foreign language communication;to standardize public bilingual notices and signs marking system;to innovate the internationalized operational models of the key industries;to create a multi-functional foreign language consulting service system. Thereby,the objective to improve the international language environment and competitiveness of the urban areas can be accomplished.
基金Sponsored by Humanities and Social Sciences Project in Northwest A&F University(2015RWYB38)
文摘Studying the urban landscape pattern plays a crucial role in scientific land use and management and in improving the urban ecological environment. In this paper, Auto CAD, Arc GIS, Fragstats, and other software were used to analyze the data of the fourth phase of land use in the core area of Yangling Demonstration Zone. The results showed that:(1) in the core area, the percentage of construction land increased from 18.22% to 61.72%, and the percentage of agricultural land decreased from 58.36% to 11.14%. And the farm land was fragmented, and traffic connectivity was strengthened. The area of garden land was reduced from 251.89 hm2 to 50.38 hm2, and the landscape metric of forest land showed an inverted V-shaped curve.(2) The year 2009 in four phases witnessed the greatest landscape fragmentation, both Edge Density(ED) and Largest Patch Index(LPI) increased, and human interference enhanced the overall landscape complexity. Measures were formulated in terms of clear development goals, optimized al ocation of land resources, effective protection of ecological red lines, and definite ecological responsibility, so as to optimize the urban landscape pattern.
文摘地理学研究可持续发展旨在构建人与自然命运共同体,实现人类社会的永续发展.该文依托CNKI数据库、读秀资源库以及Web of Science数据库,限定主题词为“可持续”“可持续发展”和“可持续性”,采用CiteSpace软件对1994—2021年中国地理学者“可持续”研究的核心力量、重点区域与重要领域进行文献计量分析,结果表明:1)中国地理学者“可持续”研究的过程可分为快速兴起(1994—2001年)、稳定发展(2002—2011年)和整固深化(2012—2021年)三个阶段.2)中国开展“可持续”研究的地理学者多达624位,主要是自然地理学者和人文地理学者,研究机构多达258个,主要是中国科学院所属地理单位,机构间合作具有空间邻近性,机构空间分布具有东、中、西梯度分异性;中国地理学者“可持续”研究的对象区域以地方行政区域为主,服务国家重大区域发展战略的特色鲜明.3)中国地理学者“可持续”研究的重点领域有资源可持续利用、生态环境保护与建设、农业可持续发展、旅游可持续发展、可持续发展教育、可持续发展伦理、消除贫困与可持续生计、区域人地关系协调、城市可持续发展、农村可持续发展、区域可持续发展战略、区域可持续发展评价等.4)未来中国地理学者的“可持续”研究应在可持续发展专业人才培养、可持续发展理论体系完善、可持续发展研究领域拓展、可持续发展服务能力提升等方面下功夫.
