The rms–flux relations in different branches in Cyg X-2

In this paper, the rms-flux (root mean square-flux) relation along the Z-track of the bright Z-Source Cyg X-2 is analyzed using the observational data of Rossi X-ray Timing Explorer (RXTE). Three types of rms-flux relations, i.e. positive, negative, and ‘arch’-like correlations are found in different branches. The rms is positively correlated with flux in normal branch (NB), but anti-correlated in the vertical horizontal branch (VHB). The rms–flux relation shows an ‘arch’-like shape in the horizontal branch (HB). We also try to explain this phenomenon using existing models.     

基于MODIS数据的地表覆盖种类与地闪分布特征关系研究

利用2008—2013年MODIS 3级数据土地覆盖类型产品MCD12Q1及重庆市ADTD闪电定位资料,以重庆市内106°~107°E,29°~30°N范围的矩形区域为研究区域,结合频次、强度、时段、地貌等要素对局地内的地表覆盖种类与地闪分布关系进行了研究,结果表明:研究区内地闪分布在各地表覆盖种类上差异显著,在水域、农田、城镇上的闪电密度都高于平均值;地闪中轻中度闪电、强闪电的分布在同一地表覆盖种类上的差异明显,强闪电更易产生于水域、林地种类上;同一地表覆盖种类上地闪分布与季节的关系不明显;地闪活动在某些地表覆盖种类上的昼夜分布具有明显差异;植被覆盖面上的地闪分布与地貌条件关系密切,同一类覆盖面上的强闪电比例与海拔高度呈正相关关系。     

巴布亚新几内亚奥克泰迪铜金矿床成矿特征和控制因素

巴布亚新几内亚西部Fubilan山奥克泰迪矿床是一个世界级铜金矿床,在大地构造上位于新几内亚造山带的巴布亚褶皱带。该矿床的铜金矿化赋存于Fubilan二长斑岩及其周边的磁铁矿夕卡岩和硫化物夕卡岩中。矿石类型以原生硫化物矿石为主,金属矿物包括磁铁矿、黄铁矿、磁黄铁矿、白铁矿、黄铜矿、斑铜矿等。蚀变类型包括夕卡岩化、钾化、泥化和青盘岩化。矿床氧化次生富集带发育,表生矿石矿物为蓝辉铜矿、辉铜矿、自然铜、铜蓝和银金矿。成矿作用主要受区域构造、侵入杂岩体、Darai组灰岩地层、断裂等因素的控制。根据矿床的主岩、矿石特征、蚀变特征和控矿因素,认为该矿床成因类型属于较为典型的夕卡岩—斑岩型矿床。     

湖南凤凰地区地质构造与汞铅锌矿成矿关系研究

汞铅锌矿是湖南凤凰地区的优势矿种。介绍了该区汞铅锌矿的地质特征及类型,结合实际地质资料,综合分析了该区构造控矿因素,初步提出了该区汞铅锌矿的构造控矿规律: 区内汞铅锌矿床成因类型主要有层控叠加(沉积改造)型矿床和断层破碎带低温热液充填型脉状矿床; 导矿构造为NNE向和NE向区域性大断裂——保靖—铜仁断裂; 控矿构造为NNE向和NE向背斜核部及两翼,以及背斜与向斜转折部位; 容矿构造为NW向小断裂、容矿层中节理裂隙、层间裂隙及破碎带。     

The blown sand disaster to the Tarim Desert Highway in Xinjiang,China

The Tarim Desert Highway in Xinjiang, China, the longest one in the world, has a length of 562 km, about 80% of which runs across, from north to south, the Taklimakan Desert. Obviously, the main problem of the road maintenance is the blown sand disaster. The research results showed: (1) the physical environment along the desert highway is characterized by strong winds, fine and loose ground materials, different dunes and so on, which provides the dynamical condition and material source for the formation of blown sand disaster to the road and its shelter system. Meanwhile, the trend and cross-section of the road and the structure of the shelter system, as damage objects, play important roles in the formation process of blown sand disaster; (2) the blown sand disaster to the shelter system is original from the intrusion of the drift sands and mobile dunes outside the shelter system, and the wind erosion and sand deposit caused by the air stream changes on the ground in the shelter system. The main damage object in the Tarim Desert Highway is the shelter system presently. The damage forms include wind erosion, sand burying and dune covering; and (3) the damaged length of the blocking sand fences is 83.7%, 88.4%, 72.4%, 72.8% and 40.3% and the damaged area of the straw checkerboard belts is 73.1%, 58.2%, 44.5%, 35.4% and 36.6%, in turn, in 5 different landform units from north to south, and, the disasters to fences and the straw checkerboard belts are 79.5% and 57.6% in the compound dunes while they are 64.6% and 37.7% in the interdunes respectively.

     

液化场地桩-土地震相互作用p-y曲线分析方法研究

目前,我国尚缺乏液化场地桩-土-桥梁结构地震相互作用分析的合理数值模型与简化分析方法。鉴于此,直接针对振动台试验,基于非线性文克尔地基梁模型,考虑桩周参振土的质量惯性力、上部结构的惯性力、土体辐射阻尼等效应,建立了液化场地桩-土-桥梁结构地震相互作用的p-y曲线分析模型,并给出相应的简化方法。针对振动台试验进行了0.1g El Centro波输入下的分析,验证了桩-土地震相互作用分析方法的正确性,并且推荐了计算参数的合理选取方法,可用于液化场地桩-土地震相互作用的分析。提出的液化场地桩-土地震相互作用p-y曲线简化分析方法,为实际桥梁桩基抗震设计与分析提供一定参考。     

郯庐断裂带南段早白垩世镁铁质岩墙成因及其地质意义

地壳再循环物质交代岩石圈地幔形成不均质的地幔源区,其衍生的镁铁质岩浆岩为揭示地幔演化及壳—幔相互作用提供了重要信息。本文对郯庐断裂带内张八岭隆起南段肥东地区镁铁质岩中的锆石进行LA‑ICP‑MS定年,获得年龄集中在127~122 Ma。镁铁质岩样品中SiO₂含量为51.33%~54.01%,Mg^#值为52.6~70.0,并具有富钠、富碱(σ = 2.46~4.22)的特征,属于亚碱性和高钾钙碱性系列。镁铁质岩样品均富集大离子亲石元素(LILEs,如Ba、Pb、K),相对亏损高场强元素(HFSEs,包括Nb、Ta、Ti等),表现为弧型地球化学特征。锆石Hf‑O同位素研究获得极负的ε_Hf(t)值(-23.4~-21.2)和略高的δ¹⁸O值(5.49‰~6.01‰),与新元古代斜长角闪岩同位素组成显示出一致的演化趋势和相似的分布特征。因此,早白垩世镁铁质岩墙富集的同位素特征主要继承于新元古代(~800 Ma)岩石圈地幔;在郯庐断裂带伸展背景下,由古老岩石圈地幔发生减压熔融形成。

     

WRF模式对山谷城市边界层模拟能力的检验及地面气象特征分析

利用先进的WRF中尺度模式中3种边界层参数化方案(YSU、MYJ和ACM2),模拟了2005年1月25~28日兰州市冬季地面温度和风速的变化,并与同期系留探空和自动气象站的实测资料进行了对比分析。结果表明:对兰州冬季大气边界层地面温度日变化的模拟,局地闭合的MYJ方案优于非局地闭合的YSU和ACM2方案;3种方案模拟的夜间位温廓线较好,白天的较差;在边界层低层,考虑局地和非局地闭合的ACM2方案模拟的位温廓线与观测值比较一致;在边界层上部,局地闭合的MYJ方案则更适合于描述大气湍流对位温垂直分布的影响;3种边界层参数化方案模拟的兰州地区冬季温度场空间分布特征相似,但MYJ方案模拟的夜间温度低于YSU和ACM2方案,白天则高于YSU和ACM2方案。     

Progress of Long-Chain Alkyl Diols in Marine Environmental Reconstruction

Long-chain alkyl diols contain an alkyl chain with alcohol groups at C1 and at the middle position of carbon chain, which exist widely in seas, rivers and lakes. It has been proven that these compounds are relatively resistant to degradation and have an extended occurrence in the geological record. In addition, they are relatively easy to identify. Therefore, long-chain alkyl diols can be used as potential biomarkers to trace the past change in paleoenvironment and paleoclimate. Although the sources of long-chain alkyl diols are still uncertain, the studies indicate that 1, 13 and 1, 15-diols are mainly produced by eustigmatophytes, while 14-diols are mainly from diatom Proboscia. So far, some proxies based on long-chain alkyl diols have been established to indicate the change in diatom productivity, upwelling intensity, salinity, sea surface temperature, riverine organic matter input and surface seawater nutrient concentration, which are significant for paleoenvironmental reconstruction. Current research and application of long-chain alkyl diols proxies were summarized, which would be helpful for further studying the source of long-chain alkyl diols and the application of relevant proxies in China’s marginal sea.     

FLAC 3D 强度折减理论在边坡稳定分析中的应用

FLAC3D 是岩土工程中广泛应用的软件。本文主要介绍强度折减理论的基本原理,利用基于强度折减法的FLAC3D 软件,对某高速公路K377 + 230 ～ K377 + 520 段滑坡体进行数值模拟。计算边坡在自重作用达到初始化平衡状态时,边坡的横向与竖直方向的应力与位移,分析出边坡的破坏机制为牵引式滑坡,通过强度折减理论计算出边坡的稳定系数为0. 97,由剪切应变增量云图确定边坡的滑动面。