The Eddington Ratio of H 2 O Maser Host AGN

The Eddington ratio λ was derived for the entire maser host AGN sample, based on the intrinsic X-ray luminosity, the X-ray bolometric correction C _X and the mass of central black hole. Further the [O III] bolometric correction C _{[O III]} was estimated for our sample. Possible relations were also investigated between the maser luminosity and the bolometric luminosity – the Eddington ratio.     

2020年12月一次北部湾海雾过程的生消特征分析

2020年12月26-28日,北部湾出现了持续性大雾,其中炮台角站连续35h出现大雾.利用北部湾沿岸海岛站、浮标站等观测资料和ERA5再分析资料,对此次典型海雾过程的生消特征进行分析.结果表明,此次海雾过程主要受人海高压后部偏东暖湿气流影响.海雾期间,北部湾上空有逆温层,大气层结稳定,湿层深厚且维持时间长,近地层有0～...     

Potential Seismic Risk in Taiwan Strait Region

GPS observation indicates that the Fujian coastal region of China mainland, the region of Taiwan Strait and northern Taiwan island all show a generally homogenous horizontal motion with weak deformation. Historical earthquake record over more than 800 years and modern instrumental data reveal that there is potential seismic risk in and around Taiwan Strait region. After the National Seismic Zoning Map of China (2001) the expected seismic risk in northern part of the Taiwan Strait is lower than that in middle and southern part. The suggested northern route of the Taiwan Strait passage project seems to be relatively save seismically.     

利用SIR-C极化数据提取地面参数

本文根据简化的积分公式模型（ＩＥＭ）,分析了面散射过程中后向散射系数与地面参数之间的关系。利用航天飞机成像雷达（ＳＩＲ－Ｃ）获取极化的雷达图像,提取新疆北部地区冲扇的散射系数以及介电常数（湿度）与粗糙度。由图像获得的地面参数数据,可以用于分布冲积扇成因、时代以及其次的关系。     

鄂尔多斯盆地上古生界山西组页岩气成藏条件及勘探潜力

为了研究鄂尔多斯盆地上古生界页岩气的勘探潜力,对鄂尔多斯盆地二叠系山西组富有机质泥页岩样品有机地球化学、物性特征及等温吸附等方面测试获得的参数进行了数理统计和测井响应特征分析。研究发现：有效泥页岩单层厚度变化较大,最厚可达15 m以上,盆地主体部位w(TOC)一般大于1.0%,有机质类型主要为Ⅱ₂型及Ⅲ型,镜质体反射率平均为1.66%,属于成熟-高成熟阶段,有利于有机质热解生气,具备页岩气成藏的基本地质条件。黏土矿物主要以伊利石（44.9%）和高岭石（33.6%）为主,泥页岩孔隙度平均为3.98%,渗透率平均为0.133×10^-3 μm²。泥页岩吸附含气量平均为1.94 m³/t。综合考虑泥页岩有效厚度、有机质丰度、有机质类型、热演化程度以及含气量等因素,预测鄂尔多斯盆地山西组页岩气有利区主要位于天环坳陷西北角、陕北斜坡带东北角及盆地中南部等区域。     

Genetic diversity and population structure of Eleutheronema rhadinum in the East and South China Seas revealed in mitochondrial COI sequences

Eleutheronema rhadinum is a potential commercial fisheries species and is subject to intense exploitation in China. Knowledge on the population structure of E. rhadinum in Chinese coastal waters, which is important for sustainable exploitation and proper resource management, is lacking. In the present study, the genetic diversity and population structure of E. rhadinum were evaluated using a 564-base pair fragment of the mitochondrial cytochrome c oxidase subunit I （COl） gene. A total of 76 specimens were collected from three localities around the East （Qidong and Zhoushan） and South China Seas （Zhuhai）. Among these individuals, nine polymorphic sites were detected and 1 l distinct haplotypes were defined. High levels ofhaplotype diversity （h=0.759i0.035） and low levels of nucleotide diversity （re=0.001 98i0.003 26） were observed in these populations, Hierarchical analysis of molecular variance （AMOVA） indicated that 96.72% of the genetic variation occurred within the populations, whereas 3.28% occurred among populations. No significant genealogical branches or clusters were recognized on the neighbor-joining tree. Intra-group variation among populations was significant （~0~t=0.032 85, P〈0.01）. These results suggest that E. rhadinum populations in the East and South China Seas have developed divergent genetic structures. Tests of neutral evolution and mismatch distribution suggest that E. rhadinum may have experienced a population expansion. The present study provides basic information for the conservation and sustainable exploitation of this species.     

Water quality evaluation in Tidal River reaches of Liaohe River Estuary, China using a revised QUAL2K model

Rivers in the Liaohe River Estuary area have been seriously polluted by discharges of wastewater containing petroleum pollutants and nutrients. In this paper, The Enhanced Stream Water Quality Model (QUAL2K) and its revised model as well as One-dimensional Tide Mean Model (1D model) were applied to predict and assess the water quality of the tidal river reach of the Liaohe River Estuary. Dissolved oxygen (DO), biochemical oxygen demand (BOD₅), ammonia nitrogen (NH₃-N) and total phosphorus (TP) were chosen as water quality indices in the two model simulations. The modelled results show that the major reasons for degraded rivers remain petroleum and non-point source pollution. Tidal water also has a critical effect on the variation of water quality. The sensitivity analysis identifies that flow rate, point load and diffuse load are the most sensitive parameters for the four water quality indices in the revised QUAL2K simulation. Uncertainty analysis based on a Monte Carlo simulation gives the probability distribution of the four water quality indices at two locations (6.50 km and 44.84 km from the river mouth). The statistical outcomes indicate that the observed data fall within the 90% confidence intervals at all sites measured, and show that the revised QUAL2K gives better results in simulating the water quality of a tidal river.     

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