基于MS60的BIM放样与施工结果精度分析     

邓明镜  冉东  杨忠轩  黄恒  李昌义 《测绘通报》2019,(3):145-147,162

随着各种异形建筑的不断出现，传统施工放样方法及检测技术已不能完全满足施工要求，因此需要引进新的施工放样及检测技术。本文结合重庆仙桃数据谷金融大楼项目，运用MS60的BIM放样与三维激光扫描技术，探究其在异形建筑施工放样及结果检测中的高效性、可靠性。在施工放样过程中，首先通过在BIM模型上选取放样点，利用MS60全站扫描仪自动搜索与追踪，简化施工放样流程；然后运用BIM模型与点云数据相结合的表面偏差分析对施工结果进行高精度分析，从而为后续施工提供参考。  相似文献   

Extraction of Lithium from Salt Lake Brine using N523-TBP Mixture System   总被引：1，自引：1，他引：0       下载免费PDF全文

SHI Dong  LI Li-juan  LI Jin-feng  JI Lian-min  SONG Fu-gen  PENG Xiao-wu  ZHANG Li-cheng  ZHANG Yu-ze  LI Hui-fang  SONG Xue-xue  NIE Feng  ZENG Zhong-min  LIU Zhi-qi  GUO Fan 《盐湖研究》2019,27(2):95-110

In this work,problems encountered by tri-butyl phosphate( TBP) in the industrialization of lithium extraction from salt lake brine were discussed in detail. The behavior of N,N-bi-( 2-ethylhexyl) acetamide( N523) during lithium extraction was investigated,and its disadvantages were analyzed in the view of practical application. An N523-TBP mixture extraction system was proposed to alleviate or avoid the defects that N523 and TBP met when they were used separately. The optimal composition of this mixture extraction system was determined to be 20% N523-30% TBP-50% kerosene.The effects of brine acidity,Fe/Li molarity ratio,phase ratio and chloride ion concentration on lithium extraction efficiency were discussed. The operation conditions in single-stage extraction were optimized as brine acidity = 0. 05 mol/L,Fe/Li molarity ratio = 1. 3,and phase ratio = 2. The high concentration of chloride ions in brine was beneficial for the extraction of lithium. The structure of the extracted complex was proposed as( LiFeCl_4·n N523·m TBP)·( 2-n) N523·( 2-m) TBP( m + n = 2) by chemical analysis and slope-fitting methods. The extraction thermodynamic functions were calculated preliminarily,and the results suggested that the extraction process was an exothermic( ΔH 0) and spontaneous( ΔG 0) reaction,and the degree of disorder increased( ΔS 0) during the extraction process. This work will give some guidance to the lithium industry of Qinghai in both the fundamental theory and practical application.  相似文献   

Identification of a Long-Chain Fatty Acid Elongase from Nannochloropsis sp. Involved in the Biosynthesis of Fatty Acids by Heterologous Expression in Saccharomyces cerevisiae     

GUO Minrui  CHEN Guogang  CHEN Jiluan  ZHENG Minggang 《中国海洋大学学报(英文版)》2019,(5)

The marine microalga Nannochloropsis sp. contains various elongases and desaturases that are critical for biosynthesis of polyunsaturated fatty acids. A full-length cDNA encoding a long-chain fatty acid elongase, named Ns FAE, was cloned from Nannochloropsis sp.. The open reading frame of Ns FAE(GenBank accession no. MF680548) consisted of 1068 bp and encoded a predicted protein of 355 amino acids with molecular mass 38.8 k Da. The deduced polypeptide showed 43%–44% identity to fatty acyl elongases from other algae. RT-PCR experiments indicated that the Ns FAE gene exhibited the highest expression in Nannochloropsis sp. at 72 h(i.e., during the third growth stage) and the expression was significantly lower in the other four growth stages. Plasmid p Ns FAE-CRISPR and a recombinant DNA fragment(ADH1p-Ns FAE-CYCt) were transformed into Saccharomyces cerevisiae strain BY4742 using the CRISPR-Cas system. Yeast transformants containing Ns FAE produced three fatty acids not normally present in wild-type BY4742-linoleic acid, linolenic acid and eicosadienoic acid-indicating that Ns FAE encodes a functional elongase enzyme.  相似文献   

Mapping Geochemical Anomalies Through Integrating Random Forest and Metric Learning Methods     

Wang  Ziye  Zuo  Renguang  Dong  Yanni 《Natural Resources Research》2019,28(4):1285-1298

Extracting geochemical anomalies from geochemical exploration data is one of the most important activities in mineral exploration. Geochemical anomaly detection can be regarded as a binary classification problem. The similarity between geochemical samples can be measured by their distance. The key issue of this classification is to find the intrinsic relationship and distance between geochemical samples to separate geochemical anomalies from background. In this paper, a hybrid method that integrates random forest and metric learning (RFML) is used to identify geochemical anomalies related to Fe-polymetallic mineralization in Southwest Fujian Province of China. RFML does not require any specific statistical assumption on geochemical data, nor does it depend on sufficient known mineral occurrences as the prior knowledge. The geochemical anomaly map obtained by the RFML method showed that the known Fe deposits and the generated geochemical anomaly area have strong spatial association. Meanwhile, the receiver operating characteristic curves for the results of RFML and another method, namely maximum margin metric learning, indicated that the RFML method exhibited better performance, suggesting that RFML can be effectively applied to recognize geochemical anomalies.

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Three Decades of Sea-Ice Variability in Jiaozhou Bay Revealed by Landsat Observations     

HUANG Jue  GUO Lianjie  JIANG Tao  ZHU Hongchun 《中国海洋大学学报(英文版)》2019,(2)

In this study, we used Landsat images and meteorological data to examine the spatiotemporal distribution and variability of sea ice in Jiaozhou Bay(JZB) between 1986 and 2016. The results show that JZB is not always covered by sea ice in winter, but in some extreme cases, sea ice has covered more than one-third of the sea area of the bay. Sea ice in JZB has generally formed between January 1 and February 5, primarily along the coast, and gradually expanding to the central area of the bay. Both meteorological and artificial factors have played important roles in modulating the sea ice distribution. We found sea ice coverage to have been strongly correlated with the accumulated freezing-degree days nine days before the occurrence of sea ice(R2 = 0.767). North-northwest surface winds have dominated the freezing period of sea water in the JZB, and wind speed has exerted a more significant influence on the formation of sea ice when the sea ice coverage has been generally small. Additionally, artificial factors began to affect the expansion of sea ice in JZB since 2007. The construction of the Jiao-Zhou-Bay Bridge(JZBB) is believed to have retarded water flow and reduced the tidal prism, thereby leading to the formation of an ice bridge along the JZBB, which effectively prevents the southward expansion of sea ice.  相似文献   

褚绍唐先生的学术思想与贡献     

周维国  张佳琦  段玉山  蒋连飞  郭锋涛 《地理学报》2019,74(8):1695-1706

褚绍唐先生是中国著名的地理教育家,历史地理学家,华东师范大学地理系教授。褚先生的地理教育思想构建起了中国中小学地理教育教学与研究的基本框架,先生组织发起的地理教育学术组织和创办的学术期刊仍发挥着巨大作用,先生编写的中小学地理教学大纲和教材惠及数代人。褚先生对上海历史地理的研究颇有建树,对上海的城市发展过程、成陆过程,水系变化等有独特见解。褚先生对《徐霞客游记》的整理和校点工作具有划时代意义,同时,先生也是徐霞客研究领域的大师。此外,褚先生还在城市地理学、地图学、地理文献翻译等领域做出了贡献。  相似文献   

川藏铁路交通廊道地质调查工程主要进展与成果     

郭长宝  王保弟  刘建康  涂杰楠  张永双  马剑飞  铁永波  韩冰  马鑫  刘峰  李雪  孟文  钟宁  杨志华  吴瑞安 《中国地质调查》2020,7(6):1-12

川藏铁路是我国正在规划建设的重点工程,由于其位于地形地貌和地质构造都极为复杂的青藏高原东部,在铁路规划建设中面临一系列迫切需要解决的关键地质问题: 区域性活动断裂与断错影响、地质灾害、高地应力及其引起的岩爆和大变形、高温热害、断裂带高压水与涌水突泥、高陡边坡稳定性等。为满足技术支撑川藏铁路规划建设、精准服务国家重大战略实施的需要,中国地质调查局部署了“川藏铁路交通廊道地质调查工程”,聚焦制约川藏铁路规划建设的关键问题,充分发挥地质调查工作对国家重大工程规划建设的支撑作用。2019年主要完成铁路沿线1:5万区域地质调查1 350 km²、1:5万地质灾害调查5 000 km²,建设6口大地热流地质参数井、8个地温监测站,完成地应力测量20孔,编制完成11份地质调查专报,提出的大渡河大桥段、理塘车站段、毛垭坝盆地段等线路优化建议/防灾建议被采纳; 首次将1:5 000大比例尺航空物探技术引入复杂山地铁路工程勘察,创新形成千米级超长水平钻孔定向取心钻进技术,实现500 m深的水平孔地应力测量突破等。该工程通过2019年调查研究,全力提升了铁路沿线地质调查程度与精度,并创新了复杂艰险山区重大工程地质问题与探测技术、地质灾害风险防控理论与减灾关键技术,有效支撑服务了川藏铁路规划建设。  相似文献   

黄连素对Aβ25-35诱导的星形胶质细胞的细胞因子及氧化应激的影响          下载免费PDF全文

童晶晶  黎军  周裕文  贺宪  曾展鹏  郭淑芬 《应用海洋学学报》2020,36(4):135-138

目的：探讨黄连素对β-淀粉样蛋白25-35（Aβ25-35）诱导的大鼠星形胶质细胞的细胞因子及氧化应激的影响。方法：培养第3代的大鼠星形胶质细胞，将其分为空白对照组、模型组、多奈哌齐组，以及黄连素低、高剂量组，分别加入相应药物培养24 h后，模型组和各药物组再加入Aβ₂₅-35。检测各组IL-1β、IL-6、TNF-α mRNA的表达及SOD、MDA水平。结果：Aβ₂₅-35浓度为20 μmol/L时星形胶质细胞增殖率最高；与空白组比较，模型组的IL-1β、IL-6、TNF-α蛋白分泌及其mRNA表达增多，伴随着MDA水平上升，SOD水平下降；与模型组比较，各药物组的IL-1β、IL-6、TNF-α蛋白分泌及其mRNA表达减少，伴随着MDA水平下降，SOD水平上升，尤以黄连素高剂量组疗效最好。结论：黄连素可降低Aβ₂₅-35诱导的大鼠星形胶质细胞的炎性细胞因子，并减少氧化应激。  相似文献   

西昆仑穆呼锰矿床地质特征、控矿因素及成矿模式     

董志国  张连昌  董飞羽  张帮禄  谢月桥  查斌  彭自栋  王长乐 《吉林大学学报(地球科学版)》2020,50(5):1358-1372

穆呼锰矿床位于西昆仑造山带玛尔坎苏锰矿带东段，研究程度相对薄弱。穆呼锰矿床的含矿地层为上石炭统喀拉阿特河组，自下而上可分为角砾灰岩、钙质杂砂岩和含炭质泥灰岩3个岩性段，具有完整的海侵层序特征，反映了由逐步断陷到稳定沉积的盆地演化过程。锰矿层赋存于第三岩性段炭质泥灰岩中，矿石矿物主要为化学组分纯净的泥晶菱锰矿。根据详细的矿相学观察并综合前人研究成果，笔者认为菱锰矿是初始沉淀的锰（氢）氧化物与有机质通过成岩反应形成的。这种成矿机制需要3个基本条件：丰富的锰质来源、氧化还原分层的海水和有机质的大量埋藏。在穆呼一带，有利于满足以上条件的主要控矿因素包括：伸展拉张的构造背景、强烈的海底热液活动、海侵事件和温暖潮湿的古气候。笔者根据w（Ba）-w（P₂O₅）图解并结合区域对比分析，初步认为穆呼锰矿床的成矿模式可能属于最小含氧量带扩张型。  相似文献   

扬子陆块~2.0 Ga的区域变质事件对南北黄陵古元古代差异演化的启示     

陈超  苑金玲  郭盼  黎方云  孔令耀  杨金香  毛新武 《中国地质》2020,47(4):899-913

扬子陆核黄陵地区发育较为完整的太古宙—古元古代片麻岩、表壳岩组合(即崆岭杂岩),前人调查研究认为南北黄陵Ar-Pt1具有一致的物质组成和地质演化过程。笔者分别对南北黄陵太古宙花岗质片麻岩进行锆石年代学研究发现,北黄陵2件样品(HL013-1、HL013-2)均存在大量锆石发育岩浆核-变质边结构,都获得～2.8 Ga原岩结晶年龄和～2.0 Ga变质年龄;而南黄陵1件样品(HL005-3)以具振荡环带结构的岩浆锆石为主,仅获得～2.9 Ga原岩结晶年龄。结合前人研究成果发现,～2.0 Ga的变质年龄在北黄陵太古宙—古元古代的花岗片麻岩、表壳岩中广泛发育,而在南黄陵相似建造中均未获得,一定程度上说明北黄陵地区广泛遭受～2.0 Ga的区域变质作用而南黄陵不发育,南北黄陵在古元古代可能处在不同地块或者同一地块不同部位。2.1～1.6 Ga的构造岩浆事件的分布特点说明扬子陆块可能存在多条古元古代造山带,扬子陆块古元古代以多块体拼贴为特点,广泛记录2.1～1.6 Ga的构造岩浆事件说明扬子陆块是全球哥伦比亚超大陆的重要组成部分。  相似文献