排序方式: 共有77条查询结果,搜索用时 62 毫秒
71.
72.
关于古代“海上丝绸之路”的几个问题 总被引:1,自引:0,他引:1
陆上丝绸之路大约出现于公元前13世纪,海上丝绸之路则是在公元前200年左右开始出现的.1840年爆发的鸦片战争,标志着古代海上丝绸之路的结束.陆上丝绸之路与海上丝绸之路是古代中国连接外部世界的两大动脉,但两者在分布方式、运输方式、对科学技术的依赖程度、外来民族移居方式等方面都有许多不同.古代海上丝绸之路与“21世纪海上丝绸之路”在内涵上有很大的不同,不能把两者等同起来.不过,古代海上丝绸之路与“21世纪海上丝绸之路”在精神层面及内在性质上有着共同的特点. 相似文献
73.
74.
Yusuke Yano Shinichi Takagawa Kazuyasu Wada 《Journal of Marine Science and Technology》2003,7(3):101-108
The Japan Marine Science and Technology Center (JAMSTEC) has been, and is now promoting the “OD21” program (i.e., “Ocean
drilling in the 21st century”). This is the first plan in the world to utilize deep-water riser-drilling technologies for
scientific drilling. One of the important factors for the success of this program is the development of a high-performance
drilling vessel. Since 1990, JAMSTEC has been continuing a technological study of a riser-drilling vessel for scientific studies
with an operational capability in waters up to 4000 m deep. It was decided to start the construction with a two-phase plan:
a vessel with a riser operation for waters up to 2500 m deep will be constructed in the initial stage, and then the vessel
will be modified to a 4000-m depth capability. In the development process of the vessel, named Chikyu, many new technical developments have taken place, such as drilling/coring equipment, a dynamic positioning system, etc.
Thus, the Chikyu is expected to contribute to ocean engineering and other work, in addition to scientific advances.
Received: June 15, 2002 / Accepted: November 11, 2002
Address correspondence to: Y. Yano (e-mail: yanoy@jamstec.go.jp) 相似文献
75.
76.
针对流凌演进三维可视化技术在冰冻河流可视化仿真方面不足的问题,结合MIKE21与ArcGIS软件,提出一种基于流凌演进数值模拟结果的可视化方法。通过模型构建、网格划分、边界条件确定,开展流凌演进数值模拟与分析,建立面向可视化的流凌演进数值模拟结果提取方法,实现流凌演进三维可视化仿真场景与数值模拟的可视化数据融合。基于空间数据库与属性数据库,建立的流凌演进仿真模拟系统,可全方位展示流凌演进过程中地形、水流、堤防结构物等仿真模拟结果。 相似文献
77.
以福州仓山龙津阳岐水系补水活水项目为例,结合项目所在区域特征,采用适合平原河网地区且能灵活调度水工建筑物的MIKE 11模型,对不同工况下的补水活水方案进行模拟。所提出的补水方案是:丰水期进行自然纳潮补水,补水方向为南引北排;枯水期因闽江潮汐动力不足,应利用泵站补水,补水方向则为东引西排和南引北排。所得结论可为后期水系运维调度提供指导。 相似文献