逆冲断层位移—长度关系解析 ——以杭锦旗断裂带为例

为了揭示鄂尔多斯盆地北部杭锦旗断裂带在晚石炭世—中三叠世逆冲断层生长的位移模式和位移—长度关系,本文通过地震剖面解释、地层回剥分析和断层古位移测算来厘定古断层的末端位置,明确断裂生长连接历史,并结合幂律关系,探究了断层生长模式以及断裂带岩性组合、运动学、反转和断层系统内在特征等方面的影响。研究表明,杭锦旗断裂带的构造演化受基底断裂的分段性制约。其北东走向的分段(泊尔江海子断裂东段)形成较早;在垂向上,断裂中部的位移大,向两端递减;在平面上,断裂末端与东西走向的分段(泊尔江海子断裂西段)叠覆,导致局部位移增大,最终发生硬连接。东西走向的三眼井断裂形成于晚石炭世,先后经历了断层分段、横向扩展和连接的演化阶段。乌兰吉林庙断裂作为调节带断裂,其活动相对较弱且局部发生反转。根据断层位移—长度剖面的几何形态和断层演化阶段分析,可将杭锦旗断裂带的逆冲阶段的位移模式分为4种类型:①近对称的三角状或椭圆状,代表独立断层;②左右极不对称的锯齿状或双峰状,代表断层之间发生软连接作用;③不规则波状,反映多条小型断层的连接作用;④异常尖峰状,代表大型断裂后期位移的调整。杭锦旗断裂带的D_(max)/L数据集与全球其他地区比较,要低一个数量级,可能与断裂带的后期反转有关。最后,针对杭锦旗断裂带在不同时期的构造演化和D_(max)/L变化特征,提出了断裂带逆冲阶段演化的路径模式。     

The trade network of the Belt and Road Initiative and its topological relationship to the global trade network

Unimpeded trade is one of the cooperation priorities in the Belt and Road Initiative proposed by China. On 15 May 2017, the Joint Communique of the Leaders Roundtable of the Belt and Road Forum for International Cooperation reaffirmed the participants’ shared commitment to build an open economy and ensure free and inclusive trade. The Belt and Road Initiative (BRI) is not only China's new action to drive its open and global development, but also a platform for an increasing number of countries to explore free and inclusive trade and promote a universal, rule-based, open, non-discriminatory, and equitable multilateral trade system. It is therefore important to examine the topological relationship between the BRI and global trade networks. More specifically, this article first analyzes the community structure of trade networks using a community detection algorithm, and then estimates the topological relationship between different trade communities. The findings of this article are as follows. First, this research identified three trade communities and two sub-communities in the BRI trade network, in which China is the core, Russia is the sub-core of the biggest trade community, and India, United Arab Emirates, and Saudi Arabia are cores of the second trade community (South Asia-West Asia). Second, it identified five trade communities in the global trade network, centred on China, USA, Russia, India-United Arab Emirates, and Germany- Netherlands-France-Britain and other European developed countries. Third, the topological analysis indicated that in the global trade network, most BRI countries are attracted by the core nodes of the BRI regions, such as the China, Russia and India-United Arab Emirates core nodes, and have strong trade contacts with BRI countries. Most Central-East European countries are mainly attracted by Germany-Netherlands-France-Britain and other developed European countries with a low penetration of BRI trade. Although some Southeast Asian countries are incorporated into the Asia-Australia-South Africa community with China as the core, they still need to strengthen trade linkages with BRI countries.     

Cloud Condensation Nuclei over the Bay of Bengal during the Indian Summer Monsoon

The first measurements of cloud condensation nuclei(CCN) at five supersaturations were carried out onboard the research vessel "Sagar Kanya"(cruise SK-296) from the south to the head-bay of the Bay of Bengal as part of the Continental Tropical Convergence Zone(CTCZ) Project during the Indian summer monsoon of 2012. In this paper, we assess the diurnal variation in CCN distributions at supersaturations from 0.2% to 1%(in steps of 0.2%) and the power-law fit at supersaturation of 1%.The diurnal pattern shows peaks in CCN concentration(NCCN) at supersaturations from 0.2% to 1% between 0600 and 0700 LST(local standard time, UTC+0530), with relatively low concentrations between 1200 and 1400 LST, followed by a peak at around 1800 LST. The power-law fit for the CCN distribution at different supersaturation levels relates the empirical exponent(k) of supersaturation(%) and the NCCNat a supersaturation of 1%. The NCCNat a supersaturation of 0.4% is observed to vary from 702 cm~(-3) to 1289 cm~(-3), with a mean of 961 ± 161 cm~(-3)(95% confidence interval), representing the CCN activity of marine air masses. Whereas, the mean NCCNof 1628 ± 193 cm~(-3) at a supersaturation of 1% is higher than anticipated for the marine background. When the number of CCN spectra is 1293, the value of k is 0.57 ± 0.03(99% confidence interval)and its probability distribution shows cumulative counts significant at k ≈ 0.55 ± 0.25. The results are found to be better at representing the features of the marine environment(103 cm~(-3) and k ≈ 0.5) and useful for validating CCN closure studies for Indian sea regions.     

真核生物mRNA折叠结构与生物功能的理论研究

简要介绍和评述了预测ＲＮＡ折叠结构（主要是ＲＮＡ二级结构）的理论方法,对以ＲＮＡ二级结构为基础的ＲＮＡ三级结构的构建方法和分子力学进行了初步探索和研究。真核细胞前体ｍＲＮＡ中内含子的剪接过程涉及剪接位点（内含子的５′、３′剪接位点和分枝点）的核苷序列与一些小蛋白质分子之间特定的专一相互作用。对大量内含子、外显子－内含子－外显子以及外显子－外显子的核苷酸片段二级结构的分析表明,剪接位点大多位于二级结构的环区。剪接位点的这种结构分布特征与剪接过程的化学反应机制相符合,并可以作为识别剪接位点的一种结构信号。对ｍＲＮＡ和由其编码的蛋白质折叠结构进行比较研究后发现,两者之间存在着相关性：两者的二级结构单元（即ｍＲＮＡ二级结构的发夹,蛋白质中α－螺旋和β－折叠片）数基本上相同;蛋白质转角区域与ｍＲＮＡ二级结构的环区对应;两者的结构元素在空间上的排布相一致等。详细分析密码子在ｍＲＮＡ二级结构中的分布还发现,密码子在ＲＮＡ二级结构中的分布规律与氨基酸的构象性质有一定联系。这些结果提示,ｍＲＮＡ与蛋白质之间除了存在一维线性遗传关系外,很可能还存在着某种三维结构的遗传关系     

澳门人地关系研究

从１６世纪中叶到２０世纪末叶,澳门的城市性质和城市功能发生多次急剧变化。人地关系一些要点在澳门的发展和变化中都有反映。澳门在浙、闽、粤沿海众多的港口中脱颖而出反映自然环境是社会是社会发展必不可少的条件。澳门成为东西方交流的桥梁反映自然环境在人地关系的演变,澳门经济转型艰难反映人文资源在人地关系中的地位呈上升趋势。澳门的城市形象和空间格局有抹不掉的自然印记,反映人地关系的发展是利用自然和利用自然规律     

皖南青阳及周边地区农业地质背景

根据农业上的应用需求,对皖南青阳及周边地区区域农业地质背景（包括区域地貌背景、地层和岩浆岩背景、地质构造和地球化学背景）进行了综合研究,并以此总结提出区域农业发展的地质制约因素和有利条件以及应该注意的地化因素的潜在影响。     

关于震磁关系"综合解释"层次的初步分析

从系统分析的角度出发,提出以磁报震的实质是综合预报,而综合预报的基础则是综合解释。作为一个认识系统,以磁报震的综合解释主要由４个层次（４个要素）组成,即地磁场异常变化（层次Ｉ）,构造环境及应力场的变化（层次Ⅱ）,系统相关要素的变化（层次Ⅲ）,外部环境要素的变化等（层次Ⅳ）。以磁报震不应简单归结为完全以地磁异常变化为基点的地震预报,而应是由多要素（层次）组成的有机分析系统,即在以层次Ｉ为核心的认识基     

新疆皮山地区地震动衰减关系研究

利用2015年7月3日皮山M_S6.5地震序列的波形资料,采用微遗传算法反演得到震源区的5个介质参数,即应力降Δσ为75.95bars,品质因子Q_0为186.33,η值为0.26,几何衰减分段点R_1为72.18km,R_2为139.70km;并由此计算得到的傅氏谱再配合随机相位谱,进而得到地震动时程,建立了震源区地震动衰减关系。由于缺乏强震记录,本文还收集了2008年10月5日乌恰M_S6.9地震、2008年10月6日阿克陶M_S6.2地震、2012年3月9日洛浦M_S6.0地震的强震数据,将计算结果与经验性衰减关系以及3次强震记录进行比较后发现,皮山地震、洛浦地震的强震数据普遍高于经验性衰减关系,乌恰地震的强震数据与俞言祥等文中的衰减关系吻合较好,在远场低于本文的计算结果。     

2020年云南省巧家县M_S 5.0地震强震动记录初步分析

2020年5月18日云南省巧家县发生M_S5.0地震,中国数字强震动台网的13个强震台站和昭通简易烈度计示范项目建设的43个烈度计台站,共接收168条强震动记录,经常规处理,绘制震区加速度峰值等值线图,并与云南地区常用地震动衰减关系进行对比,分析加速度峰值较大的几个台站频谱特性,计算地震动能量持时,讨论中小地震中高加速度峰值/低震害现象的成因,得到以下结论:(1) PGA等值线图形状较为平滑,其长轴呈NW—SE向展布;(2)云南地区常用地震动衰减关系预测值总体衰减趋势与观测值一致,但在近场(0—30 km)时,预测值基本偏小;(3)加速度峰值较大的几个台站记录主频集中在1—5 Hz;(4)小河镇台记录的能量持时较短,说明能量衰减较快,属脉冲型记录,不会对建筑物造成较大破坏。     

Radar isochronic layer dating for a deep ice core at Kunlun Station,Antarctica

The ages and accumulation rates of ice are important boundary conditions for paleoclimatic ice models. Radardetected isochronic layers can be used to date the ice column beneath the ice surface and infer past accumulation rates. A Deep Ice-Core Drilling Project has been carried out at Kunlun station in the Dome A region, East Antarctica. Radio echo sounding data are collected during the 2004/2005 Chinese National Research Expedition and the 2007/2008 Dome Connection East Antarctica project of the Alfred Wegener Institute(Germany). Radar isochronic layers from the dataset were linked to compare a new deep ice core site from Kunlun station and the Vostok ice core site. Ten visible layers, accounting for ~50% ice thickness at the Kunlun station ice core site, were dated based on the Vostok ice core chronology. At 1,640 m depth below surface, an age of ~160,400 yr was determined, corresponding to a bright layer at Kunlun station. These layers provided geometric information on the past surface of the ice sheet around the ice core site through the Wisconsin glacial stage, Eemian interglacial and Marine Isotope Stage6. Based on a simple ice flow model and the age-depth relationship, we concluded that the region around the Kunlun ice core site had lower past accumulation rates, consistent with the present pattern. The age-depth relationship would thus be expected to correlate and constrain the chronology of the deep ice core at Kunlun station in the future.