大渡河流域梯级水电站场地地震影响特征研究

本文利用四川地区及邻区的烈度衰减关系式,计算了历史强震对大渡河梯级水电站场址的影响烈度和最大烈度。同时,还分析了水电站场址在历史强震发生密集时的地震影响烈度特征,以期为今后梯级水电站的地震安全综合防御和地震应急工作提供参考。     

Period of Light Variability in BL Lac ON 231

In this paper, the authors have compiled the data of about 100 years in B-band of the BL Lac ON 231 and used this database to analyze periodicity signals in the optical light curve. Two different methods were applied: the wavelet analysis and the Discrete Correlation Function (DCF) method. We revealed the existence of periods of 13.5 years in the source variability.     

Movement and strain conditions of active blocks in the Chinese mainland

The definition of active block is given from the angles of crustal deformation and strain. The movement and strain parameters of active blocks are estimated according to the unified velocity field composed of the velocities at 1598 GPS stations obtained from GPS measurements carried out in the past years in the Chinese mainland and the surrounding areas. The movement and strain conditions of the blocks are analyzed. The active blocks in the Chinese mainland have a consistent E-trending movement component, but its N and S components are not consistent. The blocks in the western part have a consistent N-trending movement and the blocks in the eastern part have a consistent S-trending movement. In the area to the east of 90°E, that is the area from Himalayas block towards NE, the movement direction of the blocks rotates clockwisely and the movement rates of the blocks are different. Generally, the movement rate is large in the west and south and small in the east and north with a difference of 3 to 4 times between the rates in the west and east. The distributions of principal compressive strain directions of the blocks are also different. The principal strain of the blocks located to the west of 90°E is basically in the SN direction, the principal compressive strain of the blocks in the northeastern part of Qingzang plateau is roughly in the NE direction and the direction of principal compressive strain of the blocks in the southeastern part of Qingzang plateau rounds clockwisely the east end of Himalayas structure. In addition, the principal strain and shear strain rates of the blocks are also different. The Himalayas and Tianshan blocks have the largest principal compressive strain and the maximum shear strain rate. Then, Lhasa, Qiangtang, Southwest Yunnan (SW Yunnan), Qilian and Sichuan-Yunan (Chuan-Dian) blocks followed. The strain rate of the blocks in the eastern part is smaller. The estimation based on the stain condition indicates that Himalayas block is still the area with the most intensive tectonic activity and it shortens in the NS direction at the rate of 15.2 ± 1.5 mm/a. Tianshan block ranks the second and it shortens in the NS direction at the rate of 10.1 ± 0.9 mm/a. At present, the two blocks are still uprising. It can be seen from superficial strain that the Chinese mainland is predominated by superficial expansion. Almost the total area in the eastern part of the Chinese mainland is expanded, while in the western part, the superficial compression and expansion are alternatively distributed from the south to the north. In the Chinese mainland, most EW-trending or proximate EW-trending faults have the left-lateral or left-lateral strike-slip relative movements along both sides, and most NS-trending faults have the right-lateral or right-lateral strike-slip relative movements along both sides. According to the data from GPS measurements the left-lateral strike-slip rate is 4.8 ± 1.3 mm/a in the central part of Altun fault and 9.8 ± 2.2 mm/a on Xianshuihe fault. The movement of the fault along the block boundary has provided the condition for block movement, so the movements of the block and its boundary are consistent, but the movement levels of the blocks are different. The statistic results indicate that the relative movement between most blocks is quite significant, which proves that active blocks exist. Himalayas, Tianshan, Qiangtang and SW Yunnan blocks have the most intensive movement; China-Mongolia, China-Korea (China-Korea), Alxa and South China blocks are rather stable. The mutual action of India, Pacific and Philippine Sea plates versus Eurasia plate is the principal driving force to the block movement in the Chinese mainland. Under the NNE-trending intensive press from India plate, the crustal matter of Qingzang plateau moves to the NNE and NE directions, then is hindered by the blocks located in the northern, northeastern and eastern parts. The crustal matter moves towards the Indian Ocean by the southeastern part of the plateau.     

不同类别分子区域中的CO辐射巡测

用紫金山天文台青海观测站13．7米毫米波望远镜新安装的3毫米系统,对一组包括大质量恒星形成区、稠密云核、Bok球、主序前发射线星和演化晚期恒星的源进行了12COJ＝1－0的辐射搜寻．结果在不同质量恒星形成区域全部测到了12CO辐射,并发现了大的线宽、红和蓝的线翼、线心速度变化及多重辐射的特征,表明相应源可能具有双极喷流,存在膨胀、旋转或多核斑结构．有两个演化晚期星中已观测到了12COJ＝1－0谱线,说明其具有较浓厚的拱星气体包层．     

鞍山市大型导线网平差结果精度影响分析

通过城市大型一级导线网测量及其观测数据处理的实践,在平差前,根据导线网观测条件,以估算测角、测边先验中误差为基础,合理选择平差时边角先验权的匹配方案,以取得理想的平差结果.根据边角观测精度的综合因素,适当地选择几组边角先验权匹配方案进行试算,最后确定较为理想的一组边角先验权匹配方案,再进行正式平差计算和精度评定.     

Tidal regime shift in Lingdingyang Bay,the Pearl River Delta: An identification and assessment of driving factors

Both natural changes (e.g., tidal forcing from the ocean and global sea level rise) and human-induced changes (e.g., dredging for navigation, sand excavation, and land reclamation) exert considerable influences on the long-term evolution of tidal regimes in estuaries. Evaluating the impacts of these factors on tidal-regime shifts is particularly important for the protection and management of estuarine environments. In this study, an analytical approach is developed to investigate the impacts of estuarine morphological alterations (mean water depth and width convergence length) on tidal hydrodynamics in Lingdingyang Bay, Southeast China. Based on the observed tidal levels from two tidal gauging stations along the channel, tidal wave celerity and tidal damping/amplification rate of different tidal constituents are computed using tidal amplitude and phase of tidal constituents extracted from a standard harmonic analysis. We show that the minimum mean water depth for the whole estuary occurred in 2006, whereas a shift in tidal wave celerity for the M₂ tide component occurred in 2009. As such, the study period (1990–2016) could be separated into pre-human (1990–2009) and post-human (2010–2016) phases. Our results show that the damping/amplification rate and celerity of the M₂ tide have increased by 31% (from 7 to 9.2 m⁻¹) and 28% (from 7 to 9 m·s⁻¹) respectively, as a consequence of the substantial impacts of human interventions. The proposed analytical method is subsequently applied to analyse the historical development of tidal hydrodynamics and regime shifts induced by human interventions, thus linking the evolution of estuarine morphology to the dominant tidal hydrodynamics along the channel. The observed tidal regime shift is primarily caused by channel deepening, which substantially enlarged the estuary and reduced effective bottom friction resulting in faster celerity and stronger wave amplification. Our proposed method for quantifying the impacts of human interventions on tidal regime shifts can inform evidence-based guidelines for evaluating hydraulic responses to future engineering activities.     

辽宁海岸带沉积物的化学特征及其相互关系的研究

本文利用辽宁海岸带沉积物的1856个化学样品的分析资料,探讨了该区沉积物的化学要素含量与分布特征,并着重分析了各化学要素间的相互关系及其与沉积环境的关系等。     

铜陵朝山金矿床成矿地质特征和成矿预测

朝山金矿与辉石闪长岩有直接的成生关系,辉石闪长岩为金矿体的成矿母岩,构造对矿体的形成起着重要的控制作用。通过对朝山金矿成矿地质特征、矿化富集规律及找矿标志的分析和研究,指出了矿山下一步勘探工作的重点和方向。     

Geochemical characteristics of Early Cretaceous source rocks in Boli Basin

The Early Cretaceous deposits are composed of important source rocks in Boli Basin. The types of the source rocks include black mudstones and coal （with carbonaceous mudstone）. By the organic geochemical analysis methods, the authors discussed the organic petrological characters, abundance of organic matter, degree of maturity and the type of source rocks. The main micro-component of black mudstone is exinite or vitrinite, and the content of vitrinite is high in coal. The weathering of the outcrop is very serious. The abundance of organic matter in source rock reaches the poor to better rank. The major kerogens in mudstone are type- Ⅲ, type- Ⅱ 2 and some type- Ⅱ 1 ; the organic type of coal is type-Ⅲ. The thermal evolution of the source rocks in every structural unit is very different, from low-maturity to over-maturity. The depositional environment is reductive, which is good for the preservation of organic matter. The organic matter in source rocks is mainly from aquatic organisms and terrigenous input.