明清时期汉水下游地区的地理环境与堤防管理制度

明清时期国家对于汉水下游的水利管理制度经历一个变迁的过程,与这一区域的水利问题的日益突出密切相关,垸田的发展以及带来的问题是主要的因素。钟祥至沙洋的汉江干堤极易溃决,并且关系到整个下游地区的安全,因此在人力组织、资金筹集、岁修维护上,国家的政策表现出明显的倾斜性,相对于沙洋以下的区域,给予了充分的重视。沙洋以下,天门、潜江、沔阳等州县所在区域主要以垸田为主,国家将这一区域的堤防修筑与维护主要交由地方来进行。垸堤岁修维护采取堤甲制的组织形式,由垸民完成,一方面没有固定的资金,另一方面在正常年景之下,垸民可以获得基本的物质生存,因此垸堤的维护面临相当的困难。     

从政区建置看三国时期川江沿线的攻防策略

川江的特殊历史地理背景及其在三国时期的战略地位决定了围绕川江对峙的双方政权对这一地区的经营擘画。由于对峙过程的持久性和地域的复杂性,双方的军事方略均在一定程度上体现为政区建置的调整。本文即从政区建置入手,剖析三国时期两个阶段中峡口东西两个政权,即鼎立时期的蜀国与吴国以及蜀亡以后的司马氏与吴国之间,围绕川江战线的攻防策略。     

历史时期的"黄河清"现象初探

古人对黄河清有“祥瑞之兆”和“不祥之征”两种观点。黄河澄清是一种自然现象,却又不可能出现在正常条件下,它有其内在的规律。只有当流域内大范围出现异常情况,如持续干旱少雨、冬季过于寒冷、地震等时,才会导致黄河河水变异,出现黄河澄清的现象。黄河清是干旱和黄河断流的前兆。同时,黄河清还与社会政治、化和生活交织在一起,成为奇异的化与社会现象。     

The Agote Map of Hainan Island,China: A Case Study for Cultural Dialogue in Eighteenth-Century Cartography

The idea of cartography as an example of Western imposition or process of cultural transfer is one that has long fascinated scholars interested in the margins of empires. This article analyses the maps in the possession of Manuel Agote, a Spanish factor in Canton at the end of the eighteenth century. The focus is on the use made by Agote of a Chinese map of Hainan, together with the European maps available already in China for commercial interests, and the way this reflects the cultural dialogue that was operating among local and foreign cartographers engaged in similar European mapping activities in the region.     

A new temnospondyl amphibian from the Lower Triassic of South America

A new temnospondyl from the Early Triassic Buena Vista Formation (Paraná Basin) in Uruguay is described. The specimen is represented by a skull table fragment which includes the left orbit, and, although fairly incomplete, shows close affinities with the basal temnospondyl clade (Dvinosaurus + Tupilakosauridae). Previously, members of this clade were only known from Upper Permian and Lower Triassic deposits from the Northern Hemisphere. The new specimen described herein together with a recent record from the Lower Triassic of South Africa (Karoo Basin), support the hypothesis of an invasion of members of the basal (Dvinosaurus + Tupilakosauridae) clade into Gondwana as early as the Late Permian.     

The first record of a Maastrichtian ammonite from the Perth Basin,Western Australia,and its biostratigraphical significance

The first known ammonite from the Maastrichtian of the Perth Basin, a single, incomplete specimen of Grossouvrites gemmatus (Huppé, 1854), is described from core material from the Lancelin No. 1 borehole. Foraminiferal and nannoplankton evidence date the ammonite as middle Maastrichtian; its age is also assessed on the basis of dinoflagellate assemblages from this section, but these give a less precise dating. The position of the ammonite with respect to a mid-Maastrichtian disconformity, which probably extended along much of the Western Australian margin is discussed.     

长江流域史前古城的初步研究

一长江流域现已发现的史前城址（一）长江中游的史前城址长江中游现已发现的史前城址主要有湖南澧县城头山、湖北石首市走马岭、江陵阴湘城、荆门马家垸、天门石家河等。据报道湖南澧县鸡叫城,也是一座史前古城。据悉,长江中游地区现已发现的史前城址还有四、五座［１］...     

Overpressure in the Malay Basin and prediction methods

Predrill overpressure prediction is important for well planning and migration modeling for prospect evaluation. The Eaton (Journal of Petroleum Technology, 24 , 1972, 929) and Bowers (SPE Drilling & Completion, 10 , 1995, 89) methods are used worldwide for postdrill overpressure prediction using sonic log and predrill overpressure prediction using seismic interval velocity. In this research, these two methods were used for overpressure prediction using 3D anisotropic prestack depth‐migrated seismic interval velocity in a field of the Malay Basin. In the shallow overpressured zone, where the mechanism of overpressure is undercompaction, the onset of overpressure was predicted reasonably well using the Eaton and Bowers methods with their standard parameters (i.e., Eaton exponent 3 and Bowers loading curve) for seismic velocity. However, in the deep overpressured zone, where fluid expansion is the cause of overpressure generation, these methods underpredicted the high overpressure. In the deep overpressured zone, the overpressures were better predicted by applying a correction to the Eaton method. On the other hand, the Bowers unloading parameters for the fluid expansion mechanisms did not show any significant effect on overpressure prediction. Hence, in the study area, the Bowers method is not effective for 3D overpressure prediction using seismic velocity, whereas the Eaton method is more robust and can be used for 3D overpressure prediction from seismic velocity.     

近代皖北交通中心变迁再探--以津浦铁路淮河大桥选址变更为中心

临淮关凭借传统交通与商业中心的地位,成为津浦铁路淮河大桥桥址的首选之地,但由于该处地势低洼,不易建桥,桥址最终选定在蚌埠。蚌埠得津浦铁路和淮河水运之利,迅速崛起,成为皖北地区新的交通与商业中心,而临淮关则渐趋衰落,最终成为淮河岸边一个普通小城镇。究其原因,主要是由于桥址变更,引起交通区位优势的转换,蚌埠的交通优势转化为产业优势;铁路与淮河水运在蚌埠的有机结合以及政治因素的助推。     

论中国朝鲜族在图们江地区开发中的地位和作用

图们江下游开发作为一项跨国境、跨世纪的庞大工程,势必会给包括中国朝鲜族在内的3亿东北亚人民的政治、经济、文化生活带来深刻而又全面的影响,而中国朝鲜族则以其独特的地缘优势、亲缘优势、文化优势及较高的人口素质,将在图们江地区开发与东北亚经济合作中发挥不可替代的作用。