Response of silicate chemical composition variation on thermal metamorphism of ordinary chondrites and classification of petrologic types: the case of L chondrites from Grove Mountains,Antarctica     

Zhang  Chuantong  Miao  Bingkui  Xia  Zhipeng  Xie  Qinglin 《中国地球化学学报》2021,40(6):895-911

Acta Geochimica - Analysis of the thermal metamorphism of the ordinary chondrites is a key premise for gaining insights into the accretion and heating of rocky bodies in the early solar system....  相似文献   

高分辨率光学卫星影像高精度在轨实时云检测的流式计算     

王密  张致齐  董志鹏  金淑英  Hongbo SU 《测绘学报》2018,47(6):760-769

本文重点阐述基于机器视觉的智能摄影测量的效率基础问题之二：高精度影像在轨实时云检测方法。随着技术发展,数据获取能力不断提升,待处理的数据量呈爆炸式增长;同时,对处理精度需求的提升,导致所需计算量的不断增长,二者凸显了智能摄影测量面临的效率问题。对光学卫星影像而言,高达50%的平均云覆盖率严重制约了高效精准在轨智能摄影测量的实现。针对于此,本文结合机器视觉中“自底向上”的图像理解控制策略,提出一种可供借鉴的基于流式计算的高分辨率光学卫星影像高精度在轨实时云检测方法,采用适合在轨搭载的嵌入式GPU实现实时流式计算,为后续的智能摄影测量处理提供输入。本文方法采用不依赖外存的快速处理机制,对持续流入的数据实时分块,通过负载均衡机制将数据块依次分发至各个单元并行处理,从而实现“流入、处理、流出”的实时处理。利用高分二号数据对本文方法进行试验验证,结果表明本文方法在显著提高云覆盖区域检测精度的同时,综合加速比达14,可满足在轨实时处理需求。  相似文献   

Two New Species of Protocedroxylon Gothan (Pinaceae) from the Middle Jurassic of Eastern Inner Mongolia, NE China     

ZHANG Yujin  TIAN Ning  ZHU Zhipeng  WANG Yongdong  WU Xinwei  ZHANG Zhibin  ZHANG Chao  SI Qiuliang  MA Yongfei 《《地质学报》英文版》2018,92(5):1685-1699

Two new coniferous wood taxa, Protocedroxylon zhangii sp. nov. and P. zhalantunense sp. nov., are described from the Middle Jurassic Wanbao Formation in Zhalantun City, Inner Mongolia, NE China. The new discovery represents the first record of petrified wood in the Wanbao Formation, and contributes to further understanding the floral composition, especially that of the forest, of the Wanbao Formation. Anatomically, the two new species are characterized by having a mixed type of radial pitting and Abietineentüpfelung. In extant conifers, Abietineentüpfelung is considered to be characteristic of the wood of Pinaceae. The new discovery further indicates that the first occurrence of Abietineentüpfelung in conifer-like wood should be earlier than the Kimmeridgian. The palaeolatitudinal distribution pattern of Protocedroxylon indicates that the genus is a palaeobiogeographically consistent group, which was probably restricted to wetter and cooler temperate climates. In combination with distinct growth rings, the occurrence of Protocedroxylon suggests that a cool temperate and seasonal climate might have prevailed during the sedimentation period of the Wanbao Formation in eastern Inner Mongolia, NE China. Such a view is also in agreement with the palaeoclimatic conditions indicated by the plant megafossils of the Wanbao Formation.  相似文献   

The July 1, 2017 Wangjiawan landslide in Ningxiang County,China   总被引：1，自引：0，他引：1  

Yuen Zhang  Deying Li  Kunlong Yin  Lixia Chen  Yong Xu  Tsehaie Woldai  Zhipeng Lian 《Landslides》2018,15(8):1657-1662

Many landslides were triggered by heavy rainfall from 29 June to 1 July 2017 in Ningxiang County, Hunan Province, China. A field investigation into one of the landslides, known as the Wangjiawan landslide, was undertaken on July 3, 2017, to understand the landslide mechanisms and the factors that triggered the event. The landslide is a translational and rotational slide that degraded downslope to an earth flow. It occurred on a steeply dipping mud-rich slate intercalation. Field investigation shows that the landslide had a movement rate of more than 25 m/s and had been triggered by up to 338 mm of continuous rainfall over 2 days. The landslide was fast-moving because it occurred on a steep slope and showed a rapid reduction in shear strength. The landslide resulted in nine fatalities and 19 injuries, most during initial rescue efforts. To mitigate a possible secondary landslide disaster, later emergency measures including evacuation of the survivors, setting up warning signs, and covering landslide cracks with plastic sheeting were adopted.  相似文献   

Relational pattern of urbanization and economic development:Parameter re-evaluation of the Chenery model   总被引：1，自引：1，他引：0  

CHEN Mingxing  TANG Zhipeng  BAI Yongping  ZHANG Xiaoping 《地理学报(英文版)》2015,25(8)

  相似文献   

基于数据挖掘和网络药理学探讨中药治疗化疗相关性恶心呕吐的用药规律和机制          下载免费PDF全文

房立源  李慧杰  王志鹏 《应用海洋学学报》2022,38(8):29

目的：分析和挖掘中医药治疗化疗相关性恶心呕吐（CINV）的用药特点、潜在关联规则及配伍规律,并借助网络药理学和分子对接技术探讨高频药物干预CINV的作用机制。方法：收集中国知网（CNKI）、万方数据（WANFANG DATA）、维普中文科技期刊数据库（VIP）中2000年1月1日至2020年12月31日发表的中医药治疗CINV的随机对照文献,采用统计描述、关联规则、聚类分析等方法探讨中药治疗CINV的用药规律。利用 TCMSP数据库收集相关活性成分,进行靶点预测,利用DAVID数据库进行京都基因与基因组百科全书（KEGG）通路富集分析,使用分子对接技术对核心化学成分与关键靶点进行分子对接验证。结果：共纳入符合要求的文献101篇,涉及中药141味;高频核心药物主要有甘草、半夏、茯苓、白术和陈皮,中药功效以补虚和化痰为主;关联组合提升度较高者为“半夏-大枣-甘草→生姜”等;共筛选得到核心药物活性成分131个,作用靶点151个,认为高频核心药物可能通过神经活性配体-受体相互作用、钙信号通路和5-羟色胺能突触等作用机制对CINV发挥作用。结论：中医药治疗CINV以健脾化痰止呕为法,多采用补虚药、化痰药、理气药,其中甘草、半夏、茯苓、白术、陈皮为高频核心药物,网络药理学和分子对接结果进一步验证了高频核心药物治疗CINV的微观作用机制。  相似文献   

场景规划：助力城市群协同发展     

郭晨  冯舒  汤沫熙  唐正宇  杨志鹏 《热带地理》2022,42(2):305-317

通过梳理国内外场景理论的发展脉络,对场景内涵及要素特征进行了深入解读与分析,构建了包含场景要素、场景层级特征和场景规划方法在内的场景规划理论体系,从场景识别、场景构建、场景评价和场景应用视角实现了对场景规划工具的全新探索,用于指导在不同领域开展场景实践工作。并以粤港澳大湾区城市群协同发展为例,基于场景规划方法挖掘湾区的现状问题和发展目标,识别出代表未来湾区城市群协同发展方向的重要场景。最后以粤港澳大湾区城市群生态廊道构建为应用示例,初步应用场景规划方法进行场景要素分析,为下一步开展场景评价及场景应用示范等实践探索工作提供基础。  相似文献   

一块新发现月球陨石MIL090036的岩相学和矿物学          下载免费PDF全文

谢兰芳缪秉魁  陈宏毅夏志鹏 姚杰 《极地研究》2013,25(4):342-351

MIL090036是一块在南极新发现的月球陨石,属于斜长岩质月球角砾岩。本文对这块陨石开展了详细的岩石学、矿物学特征观察与研究。MIL090036月球陨石具有典型的碎屑结构。碎屑包括岩屑、矿屑和玻屑。岩屑类型有斜长岩岩屑、辉长质斜长岩岩屑、辉长岩岩屑、风化角砾岩岩屑、橄长岩岩屑、微斑熔融角砾岩岩屑、复合角砾岩岩屑等;矿屑有辉石、斜长石、橄榄石、钛铁矿等;玻屑主要为长石质。基质由玻璃质、重结晶的细粒矿物和矿屑胶结组成。辉长岩岩屑中的斜长石（An81-83）和斜长岩中的斜长石(An88-93)较其他碎屑中的斜长石(An90-98)贫钙。岩屑、矿屑和长石质玻屑中的辉石相对贫铁（Fs 12-35Wo3-44 En22-79）,而含玻璃质的辉长岩岩屑中的辉石（Fs37-65Wo10-29 En21-49）与基质中的辉石（Fs18-69Wo3-45 En14-50）相对富铁。辉长岩质斜长岩中辉石成分变化范围最小（Fs24-27Wo7-14 En59-69）。矿屑橄榄石和分布于基质中的橄榄石铁镁含量（Fo57-79）相对岩屑中的橄榄石(Fo67-77) 变化范围大。橄榄石Fe/Mn比值为47-83（平均76）、辉石Fe/Mn比值为76-112（平均73）,都与月球橄榄石和月球辉石一致。岩石结构、矿物模式组合和化学成分等特征表明MIL090036是来自Apollo和Luna采样范围外的样品。对MIL090036的矿物学、岩石学和化学成分的进一步研究将能够丰富我们对月表物质组成和演化的认识。  相似文献   

西秦岭金厂石英闪长岩的岩浆混合成因：岩相学和锆石U-Pb年代学证据及其构造意义   总被引：7，自引：0，他引：7  

刘志鹏  李建威 《地质学报》2012,86(7):1077-1090

位于西秦岭南部的金厂石英闪长岩岩体内含有大量镁铁质暗色微粒包体,包体大多呈浑圆状和水滴状,部分呈不规则拉长状,与寄主岩的接触界线截然或呈渐变过渡关系。石英闪长岩中的磷灰石呈短柱状,而包体中的磷灰石则呈细长针状,反映基性岩浆的快速冷凝结晶。石英闪长岩中的斜长石发育振荡环带,核部的斜长石An低,而边部斜长石An先急剧上升,复又下降;核部与边部之间存在明显的间断,同时斜长石边部包裹有暗色矿物,指示其形成时可能有更基性的岩浆注入。寄主岩中的角闪石大多为普通角闪石和镁普通角闪石,属SiO2饱和型,而包体中角闪石一部分为镁普通角闪石,属SiO2饱和型,一部分为韭闪石、韭闪石质普通角闪石,属SiO2不饱和类型。包体中的角闪石自核部到边部,Al2O3与TiO2含量急剧下降,说明核部和幔部相对于边部形成于更高温的环境。寄主岩中黑云母部分为铁质黑云母,部分为镁质黑云母,而包体中黑云母均为镁质黑云母,在∑FeO/(∑FeO+MgO)对MgO图解上寄主岩与包体中黑云母均落入壳-幔混源区。寄主岩和包体中的锆石均为典型的岩浆锆石,LA-ICP-MS锆石U-Pb定年表明它们的形成年龄分别为212±2Ma及215±1Ma(2σ),在误差范围内基本一致,证明二者同时形成。综合以上岩相学和年代学证据认为,金厂石英闪长岩和镁铁质暗色微粒包体是幔源基性岩浆和壳源酸性岩浆混合作用的产物,形成于秦岭造山带中三叠世造山后伸展环境。结合区域上的研究结果认为,中—晚三叠世时期的幔源岩浆底侵和下地壳部分熔融在西秦岭广泛存在。  相似文献   

Dynamic Field Division of Hydrocarbon Migration,Accumulation and Hydrocarbon Enrichment Rules in Sedimentary Basins   总被引：1，自引：0，他引：1  

PANG Xiongqi  LIU Keyu  MA Zhongzhen  JIANG Zhenxue  XIANG Caifu  HUO Zhipeng  PANG Hong  CHEN Junqing 《《地质学报》英文版》2012,86(6):1559-1592

Hydrocarbon distribution rules in the deep and shallow parts of sedimentary basins are considerably different, particularly in the following four aspects. First, the critical porosity for hydrocarbon migration is much lower in the deep parts of basins: at a depth of 7000 m, hydrocarbons can accumulate only in rocks with porosity less than 5%. However, in the shallow parts of basins (i.e., depths of around 1000 m), hydrocarbon can accumulate in rocks only when porosity is over 20%. Second, hydrocarbon reservoirs tend to exhibit negative pressures after hydrocarbon accumulation at depth, with a pressure coefficient less than 0.7. However, hydrocarbon reservoirs at shallow depths tend to exhibit high pressure after hydrocarbon accumulation. Third, deep reservoirs tend to exhibit characteristics of oil (–gas)–water inversion, indicating that the oil (gas) accumulated under the water. However, the oil (gas) tends to accumulate over water in shallow reservoirs. Fourth, continuous unconventional tight hydrocarbon reservoirs are distributed widely in deep reservoirs, where the buoyancy force is not the primary dynamic force and the caprock is not involved during the process of hydrocarbon accumulation. Conversely, the majority of hydrocarbons in shallow regions accumulate in traps with complex structures. The results of this study indicate that two dynamic boundary conditions are primarily responsible for the above phenomena: a lower limit to the buoyancy force and the lower limit of hydrocarbon accumulation overall, corresponding to about 10%–12% porosity and irreducible water saturation of 100%, respectively.  相似文献