奎屯河山前扇形地的地质灾害分析

奎屯河山前扇形地(简称奎屯扇形地)特有的自然地理条件,存在地震、洪水、泥石流、滑坡、崩塌和尘暴等多种地质灾害,并具有特殊的发生规律和表现形式,本文通过调查研究对地段性的地质灾害活动进行了分析、评价,初步提出有方向性的躲避和有目标性的抗灾.以及主动控制的治理措施.     

The Lagoon of Venice： geological setting,evolution and land subsidence

The paper deals with the geological setting, history and subsidence of the Venetian Plain. Major attention is paid to the Pleistocene-Holocene stratigraphic sequence in the Lagoon of Venice, in relation to its origin that datesback to 6-7 kyr BP. Geological land subsidence, which played an important role in the origin and the evolution of the lagoon, and anthropogenic subsidence, that has recently assumed a major importance for the Venetian environment, are discussed. Considering also the sealevel rise, 23 cm loss in land elevation has occurred in the last century, leading to increased flooding events and environmental problems that require protective works.     

Optical Flash of GRB 990123: Constraints on the Physical Parameters of the Reverse Shock

The optical flash accompanying GRB 990123 is believed to be powered by the reverse shock of a thin shell. With the best-fit physical parameters for GRB 990123 and the assumption that the parameters in the optical flash are the same as in the afterglow, we show that: 1) the shell is thick rather than thin, and we have provided the light curve for the thick shell case which coincides with the observation; 2) the theoretical peak flux of the optical flash accounts for only 3×10~-4 of the observed. In order to remove this discrepancy, the physical parameters, the electron energy and magnetic ratios, εe and εB, should be 0.61 and 0.39, which are very different from their values for the late afterglow.     

BPM载频产生器的研制

介绍ＢＰＭ短波授时台新的载频产生器的设计与实现，该ＢＰＭ载频产生器以原子频标的５ＭＨｚ标频信号为参考，利用频率合成技术，产生出供发射机使用的２．５ＭＨｚ、５ＭＨｚ，１０ＭＨｚ、１５ＭＨｚ和２０ＭＨｚ五种高准确度的载频信号。这些信号既能单独输出，也可利用面板控制或遥控选择输出。为了保证系统的可靠性，采用了两冗余结构，并设置了必要的报警与指示。     

我国旅游资源开发经营与供地政策探讨

随着社会经济的飞速发展,我国旅游业开始进入加速发展时期,新技术、新观念和新的旅游环境冲击着传统的旅游观念,工业旅游、农业旅游、生态旅游和会展旅游等逐步成为新的热点。巨     

地壳演化与成矿作用——以川滇地洼系“四层楼”铜矿床序列为例

提出川滇地洼系“四层楼”铜矿床序列的形成与陆壳演化的成生联系,是与本区陆壳由前地槽—地槽—地台—地洼演化各阶段与之相匹配的成矿作用的产物.与此同时,并总结了本区“四层楼”铜矿床序列的成矿作用具有明显的继承性、新生性、旋回性及层控性四大特点和多因复成矿床的成矿模式.     

关于南黄海地震区(带)的厘定及其有关的问题

笔者通过对南黄海的地震活动特征分析研究,认为该区的地震活动水平远高于扬州-铜陵地震带,应作为一独立的地震区(带)存在,以利于对该海域的地震研究和监测;并对其地震活动有关的若干问题提出讨论