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141.
Deng Xiangzheng Jin Gui He Shujin Wang Chengxin Li Zhaohua Wang Zhanqi Song Malin Yang Qingyuan Zhang Anlu Chen Jiancheng 《地理学报(英文版)》2021,31(3):437-455
In this paper,we review the research progress in development geography since the 20th century,focusing on its connotation and theory,fields,methods,and development trends.Specifically,we systematically review the research and applications of development geography,comprising fields such as the convergence of underdeveloped countries and re-gions,and the convergence of the process of improving the quality of life in developed coun-tries and regions.Then,based on an analysis of research progress in development geogra-phy in foreign countries,we examine the development conditions and disciplinary advantages of development geography in China.Further,we highlight that future development geography research in China should focus on the latest international academic research and China's national macro-strategic needs.Future research in development geography should be guided by the theory of sustainable development,the core of which is to improve sustainable liveli-hood capacity and regional green development levels in underdeveloped regions.This core includes the construction of industrial policy and development geography theory,as well as an interdisciplinary integrated research system.The focus must be placed on researching the spatial patterns,diffusion characteristics,and the convergence mechanism of regional de-velopment.Such a focus will facilitate exploration of the regulatory policies and scientific paths that serve regional economic construction and industrial development. 相似文献
142.
应用透射电子显微镜技术研究了我国海域耳鲍精子发生的全过程。结果表明,耳鲍精原细胞呈近椭圆形,染色质分布较均匀,线粒体较少;初级精母细胞较大,染色质凝聚成小块状,线粒体增多;次级精母细胞较初级精母细胞小,线粒体较多,部分线粒体发生融合,呈扁囊状。分化早期精细胞染色质凝聚成团块状,多数贴附于核膜内面,胞质中出现前顶体颗粒。分化中期精细胞染色质继续凝聚成较大的团块,线粒体在核的一端融合,形成数量少、体积大的线粒体,前顶体颗粒形成圆形外膜明显的前顶体。分化后期精核由近圆形变成长桶状,核内染色质凝聚并均质化,前顶体泡化发育成顶体,鞭毛形成,精细胞分化成精子。成熟精子为鞭毛型精子,由头部、中段和尾部(鞭毛)3部分组成。 相似文献
143.
由于地震孕育过程的复杂性和观测技术的局限性,不同地震观测资料表现出异常变化与后续较大地震的对应关系存在不确定性,因此对预测意见进行概率表达是一种科学恰当的做法。本文基于泊松分布的危险区背景地震概率预测和单项预测方法(包括测震、流体、形变、电磁等学科)的历史预测效能,采用贝叶斯定理计算得到单项预测方法的短期或年度地震危险概率预测结果,进而采用综合概率方法,给出基于多种单项预测方法的短期或年度地震危险概率预测结果。短期概率预测初步结果表明,2018年2~9月,中国大陆72%的5级以上地震都位于相对高概率预测区域。 相似文献
144.
西南极利文斯顿岛晚三叠世迈尔斯陡崖组形成于海底浊积扇中扇的上、下部分,发育着许多海相遗迹化石.在采集到的样品中鉴定共有15个遗迹属、16个遗迹种,其中有10个可以鉴定到遗迹种、两个比较种,4个只鉴定到遗迹属,未鉴定到遗迹种;并建立了1个新遗迹属及新遗迹种是文献中从未发现的.除新遗迹属种外,其余14个遗迹属,15个遗迹种都曾经在深海相浊积岩内发现过,Belorhaphe、Glockerichnus、Lophoctenium、Rhabdoglyphus、Paleodictyon、Sublorenzinia、Spirophycus、Strobilorhaphe、Tuberculichnus、Cochlichnus等属于浊流前产生在深海相泥岩内的高度分异的雕画迹(Graphoglyptida),它们产于泥岩却保存为上覆砂岩底面的铸型凸起.Fucusopsis和Neonereites却产生在砂岩内代表浊流后形成的沉积后遗迹组合.这些遗迹化石属深水的Nereites遗迹相,为研究区的沉积环境增添了可靠依据. 相似文献
145.
LI Jie HU Jin-ming DENG Wei HUANG Sheng-li JIA Hai-feng ZHU Chun-ling LUO Huai-xiu 《山地科学学报》2013,10(4):553-563
Mountains and plateaus in Southwest China contain many subalpine and alpine wetlands, with significant hydroecological functions. But ungauged or poorly gauged conditions limit the study and understanding of hydrological regimes of these wetland types. This study selects an ungauged subalpine wetland-Napahai in Northwest Yunnan, China-as a case for developing a practical approach to revealing its storage-area relationship of open water. A Trimble R8 GNSS (Global Navigation Satellites Systems) RTK (Real-time Kinematic system) and sonar fathometer were used to survey fine-resolution elevation data and generate a digital elevation model of the Napahai Wetland. Forty-four Landsat images from 1987 to 2011 were collected, and the Normalized Difference Water Index was used to classify open water features in the area. The area of open water in Napahai was calculated for each phase. With these data and a developed conceptual model, the storage of open water for each phase was estimated using ArcGIS tools. Both storage and area of open water showed significant intra-annual and inter-annual variations. In the rainy season, the monthly change of average storage of open water in Napahai showed about 1-2 months lag behind mean monthly rainfall. The storage-area relationship of open water was well fit by a power function equation (R 2 ≈0.91, n=44). This study indicates that if detailedelevations are available for similarly ungauged subalpine wetlands in Southwest China, researchers can use this practical approach to estimate multi- temporal areas and storages and reveal the storage-area relationship of open water in the wetlands. The study provided valuable information of this case wetland for optimizing its hydro-ecological managements and a new method to wetland researchers and managers for the hydrological study of similarly ungauged wetland complex. 相似文献
146.
Liu Zhankun Chen Jin Mao Xiancheng Tang Lei Yu Shuyan Deng Hao Wang Jinli Liu Yuqiao Li Shoulei Bayless Richard C. 《Natural Resources Research》2021,30(6):3987-4007
Natural Resources Research - The Xiadian orogenic deposit with?~?100 t of gold resources, located in the Jiaodong Peninsula, Eastern China, shows an economically attractive gold... 相似文献
147.
148.
Sediment cores from Lake Pupuke in Auckland City, New Zealand, contain a high‐resolution millennial to centennial‐scale record of changing climate and catchment hydrology spanning the past ca. 10 000 years. Here, we focus on the period between 9500 ± 25 and 7000 ± 155 cal. yr BP during which grain size, diatom palaeoecology, biogenic silica concentrations, sediment elemental and carbon isotope geochemistry reflect changes in sediment sources and lake conditions, with a significant event commencing at ca. 8240 cal. yr BP, commensurate with a lowering of lake level, faster erosion rates and increased sediment influx with a duration of ca. 360 yrs. However, the changes in the lake are not reflected in the terrestrial vegetation, where the pollen record indicates that podocarp forest dominated the Auckland region, with apparent environmental stability during this part of the early Holocene. The synchronous change in most of the proxies between ca. 8240 and 7880 cal. yr BP at Lake Pupuke indicates the presence of a sustained episode of relatively low lake level and concomitant increased rate of erosion in the early Holocene that appears to be at least partly coeval with the 8200 cal. yr BP meltwater event proposed for the North Atlantic region. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
149.
为了进一步了解我国北方新生代玄武岩地下水的赋存规律和形成演化机理,以河北省张北县玄武岩地下水为研究对象,在野外采集地下水样、测定水化学和同位素组成的基础上,利用统计分析、离子比例系数、氢氧同位素、反向地球化学模拟等方法,对区内玄武岩地下水的水化学形成机制进行了研究。结果表明:沿地下水径流方向,研究区内玄武岩地下水中多数离子质量浓度呈现增大趋势,补给区的地下水化学类型以HCO3-Ca·Mg为主,TDS质量浓度多小于500mg/L,排泄区地下水中阴离子以Cl-和SO42-为主,阳离子以Na+为主,TDS质量浓度多大于1 400mg/L;研究区地下水补给来源为当地大气降水;硅铝酸盐、岩盐、硫酸盐的风化溶解是地下水中离子的主要来源;溶滤作用、阳离子交替吸附作用和农业施肥等人类活动影响是控制地下水化学形成的主要作用。 相似文献
150.
青藏高原岩石圈演化的记录:藏北超钾质及钠质火山岩的岩石学与地球化学特征 总被引:44,自引:12,他引:44
藏北鱼鳞山超钾质火山岩为一中等规模的熔岩被, 可分为三期。前两期主要为霞石黝方白榴石响岩、霞石白榴斑岩等, 后期主要为方钠石霓石粗面岩、霓霞粗面岩等。时代为18~30 Ma。本区超钾质岩浆 Si O2 强烈不饱和、强碱性、高度富集 L R E E及 L I L E、放射成因 Sr、 Pb 及非放射成因 Nd 同位素 (86 Sr/87 Sr= 0708766~0709162, 206 Pb/204 Pb= 18882888~ 19104751, 207 Pb/204 Pb= 15642037 ~ 15828458, 208 Pb/204 Pb= 39138921 ~ 39686835 及143 Nd/144 Nd= 0512116 ~0512342),其上述特征指示岩浆源区为受到地壳物质强烈交代的富集 E M I I型地幔。藏北拉嘎拉钠质碱性橄榄玄武岩为高原面上的剥蚀残丘, 时代为60 Ma。其岩石学、 R E E、微量元素及 Sr Nd Pb 同位素指示了岩浆源区为受到洋壳俯冲物质交代的轻度富集地幔。本研究结果指示, 羌塘高原南部富集地幔的形成可能是受到印度板块俯冲的影响。 相似文献