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Research on Hydraulic Block Scenarios in the Land Conservation Zone of the Headwaters Area of Jinshu Bay 被引量:2
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作者 YAN Hong-fei,WU Wei-wei,ZHU Xue-dan,CAO Hui Shanghai Investigation Design & Research Institute,Shanghai 200434,China 《Meteorological and Environmental Research》 CAS 2011年第7期83-86,共4页
[Objective] The aim was to study the hydraulic block scenarios in the water source land conservation zone in Jinshu Bay so as to ensure the water quality in the water sources in Jinshu Bay.[Method] By dint of one dime... [Objective] The aim was to study the hydraulic block scenarios in the water source land conservation zone in Jinshu Bay so as to ensure the water quality in the water sources in Jinshu Bay.[Method] By dint of one dimension water amount and water quality mode in the river net in Taihu,the water flow movement characteristics and pollutants transportation rules in the water sources areas in Jinshu Bay under five kinds of hydraulic block scenarios were compared and discussed.[Result] After demolishing the temporary soil dam in the water source conservation zone in Jinshu Bay,water amount and pollutants increased and water quality deteriorated.It was necessary to take certain hydraulic power to block and control the pollutants in the preservation area;after demolishing the dam,there was less water amount and pollutants.The water quality improved significantly.The hydraulic block facility in the preservation area and its surroundings were all releasing and not introducing;the one along the mouth of the river of Mentianji Gang,Jinshugang and Longtanggang were introducing and not releasing,which only restricted poor-quality water in Beijing-Hangzhou Canal and Huguang Canal flowing into the conservation zone.The water into the conservation zone was all from Gonghu.The water mobility within the conservation zone was good.The regional water quality improved to the largest scale.[Conclusion] Judging from the water flow movement characteristics and pollutants transportation rules in Jinshu Bay,the fifth proposal was more appropriate. 展开更多
关键词 The headwaters area of Jinshu Bay Water movement Pollutants transportation Hydraulic block China
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Study on distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background 被引量:32
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作者 韩渭宾 蒋国芳 《地震学报》 CSCD 北大核心 2004年第2期211-222,共12页
In the paper, the distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background, especially the relation to Sichuan-Yunnan and Sichuan-Qinghai crustal blocks have b... In the paper, the distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background, especially the relation to Sichuan-Yunnan and Sichuan-Qinghai crustal blocks have been studied. The main results are: a) Strong earthquakes in Sichuan-Yunnan area distribute mainly in Sichuan-Yunnan and Sichuan-Qinghai crustal blocks; b) Most of strong earthquakes of the two blocks distribute mainly along their boundary faults; c) A few strong earthquakes are not obviously related to active faults. It shows that the relation between strong earthquakes and geological tectonics can be very complex; d) There is a certain correlativity for seismic activities among boundary faults of the two blocks, but they have different features; e) There are some anomalous changes of velocity structures in the deep crust of boundary faults of the two blocks. Many boundary faults, especially Longmenshan fault, cut obviously the Moho discontinuity. The Xianshuihe fault, a typical strike-slip fault, has no obvious indication of cutting the Moho discontinuity, but has distinct low-velocity zone in different depths. 展开更多
关键词 川滇地区 地震活动性 地壳块体 深部结构 强震活动 分布特征
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Detrital Zircon U-Pb Geochronologyof Sinian–Cambrian Strata in the Eastern Guangxi Area, China 被引量:6
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作者 Ruxin Ding Heping Zou +5 位作者 Kyoungwon Min Feng Yin Xiaodong Du Xuxuan Ma Zhangxin Su Wenjie Shen 《Journal of Earth Science》 SCIE CAS CSCD 2017年第2期295-304,共10页
The Eastern Guangxi area locates in the southwestern part of the transition zone between Yangtze and Cathaysia blocks, which is an important region because the boundary between two blocks probablycrosses there. We det... The Eastern Guangxi area locates in the southwestern part of the transition zone between Yangtze and Cathaysia blocks, which is an important region because the boundary between two blocks probablycrosses there. We determined LA-ICPMS U-Pb ages for detrital zircons extracted from three sandstone samples in the Sinian-Cambrian strata in this region. The resulting ages are in the range of the Archeozoic and Neoproterozoic, with three notable concentrates at 991 Ma, 974 Ma, and 964 Ma, all of which are coeval to the Grenvillian magmatic activity. The new age distribution is similar to the data reported in the Precambrian strata of the adjacent southwestern Cathaysia Block, suggesting that most of our detrital zircons are likely derived from the Cathaysia Block. Combined with others' research, we are more inclined to accept the opinion that there was not an ocean basin between the two blocks during the Sinian-Cambrian period in Eastern Guangxi area if the timing of collision is the Early Neoproterzoic. But if the timing of collision is the Early Paleozoic, we conclude that Luzhai uplift(i.e., the uplift between Guilin-Yongfu faultand Lipu fault) beyond the west of Dayaoshan regoin might be one part of southwestern sedimentation boundary of Cathaysia Block and Yangtze Block. We also get a few of detrital zircons with ages of ~590 Ma which probably sourced from northeastern Gondwana and 13 detrital zircons with over 3 000 Ma U-Pb ages which record the early formation of the earth. 展开更多
关键词 Cathaysia block Yangtze block eastern Guangxi area detrital zircon U-Pb dating
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The Trace Element Distribution Patterns of Ediacaran-Early Cambrian Black Shales and the Origin of Selenium in the Guangning Area, Western Guangdong Province, South China 被引量:4
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作者 TIAN Xinglei LUO Kunli Andrew V.ZUZA 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第6期1978-1991,共14页
The Ediacaran and early Cambrian black shales are widespread across the South China Craton (Yangtze and Cathaysia blocks). However, the trace element distribution patterns of the Ediacaran and early Cambrian black s... The Ediacaran and early Cambrian black shales are widespread across the South China Craton (Yangtze and Cathaysia blocks). However, the trace element distribution patterns of the Ediacaran and early Cambrian black shales in the Cathaysia Block are still unclear. In this study, thirty- four black shale samples in the Lechangxia Group (Ediacaran) and thirteen black shale samples in the lower Bacun Group (early Cambrian) from Guangning area, western Guangdong Province, South China, were analyzed for major and trace elements concentrations. Compared to the upper continental crust, the Ediacaran black shales exhibit strongly enriched Se, Ga, and As with enrichment factor values (EF) higher than 10, significantly enrichedBi and Rb (10〉EF〉5), weakly enriched Mo, Ba, Cs, V, In, Be, TI, and Th (5〉EF〉2), normal U, Cr, Cd, Sc, Pb, Cu, and Li (2〉EF〉0.5), and depleted Ni, Zn, Sr, and Co. Early Cambrian black shales display strongly enriched Se, Ga, and As, significantly enriched Ba, Bi, and Rb, weakly enriched Mo, Cs, Cd, V, U, Be, In, and TI, normal Sc, Th, Cr, Li, Cu, Ni, and Pb and depleted Co, Zn, and Sr. Moreover, Se is the most enriched trace element in the Ediacaran and early Cambrian black shales: concentrations vary from 0.25 to 30.09 ppm and 0.54 to 5.01 ppm, and averaging 4.84 and 1.72 ppm, with average EF values of 96.87 and 34.32, for the Ediacaran and early Cambrian shales respectively. The average concentration of Se in the Ediacaran black shales is 2.8 times higher than that of early Cambrian black shales. Se contents in the Ediacaran and early Cambrian black shales exhibit significant variation (P = 0.03). Provenance analysis showed that Se contents of both the Ediacaran and early Cambrian black shales were without detrital provenance and volcanoclastic sources, hut of hydrothermal origin. The deep sources of Se and the presence of pyrite may explain the higher Se contents in the Ediacaran black shales. Similar with the Se-rich characteristics of the contemporaneous black shales in the south Qingling Mountain and Yangtze block, the Ediacaran and early Cambrian black shales in Guangning area, Cathaysia, are also enriched in Se, which may provide a clue for looking for the selenium-rich resources in western Guangdong Province. 展开更多
关键词 black shale SELENIUM Ediacaran and early Cambrian Guangning area Cathaysia block
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Geo-Spatial Database Creation for Wazirabad Canal Command Area 被引量:1
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作者 Chalumuri Ramesh Naidu M. V. S. S. Giridhar 《Journal of Geographic Information System》 2011年第4期290-297,共8页
GIS assist in specific planning and decision-making processes in irrigation through the input, spatial analysis and output of relevant information. The real strength of GIS is its ability to integrate information. Thi... GIS assist in specific planning and decision-making processes in irrigation through the input, spatial analysis and output of relevant information. The real strength of GIS is its ability to integrate information. This integration power makes the scope of GIS almost infinite. The unique integration capability of GIS allows disparate data sets to be brought together to create a complete picture of a situation. GIS technology illustrates relationships, patterns and connections that are not necessarily obvious in any one data set but are amazingly apparent once the data sets are integrated. GIS also helps us to assess the performance of the irrigation command areas. GIS based system helps a canal to analyze the spatial information about its engineers and farmers to improve planning, management and supply of water resources to its corresponding blocks. In order to manage the water efficiently in the command area, it is needless to say that calculation and evaluation of water demands in detail at block and minor level to be given overriding priority. Blocks and Chak boundaries can be delineated from the Digital Elevation Model using GIS techniques. These boundaries will help to plan and allocate the water resources to improve the water allocation strategies and in turn water use efficiency and can make inter-canal comparisons. The delineated block boundaries can be refined exactly using the drainage, topography and existing canal network in GIS platform. 展开更多
关键词 GIS COMMAND area block Chak
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Study on distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background 被引量:1
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作者 HAN Wei-bin(韩渭宾) +1 位作者 JIANG Guo-fang(蒋国芳) 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第2期230-243,共14页
In the paper, the distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background, especially the relation to Sichuan-Yunnan and Sichuan-Qinghai crustal blocks have b... In the paper, the distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background, especially the relation to Sichuan-Yunnan and Sichuan-Qinghai crustal blocks have been studied. The main results are: a) Strong earthquakes in Sichuan-Yunnan area distribute mainly in Sichuan-Yunnan and Sichuan-Qinghai crustal blocks; b) Most of strong earthquakes of the two blocks distribute mainly along their boundary faults; c) A few strong earthquakes are not obviously related to active faults. It shows that the relation between strong earthquakes and geological tectonics can be very complex; d) There is a certain correlativity for seismic activities among boundary faults of the two blocks, but they have different features; e) There are some anomalous changes of velocity structures in the deep crust of boundary faults of the two blocks. Many boundary faults, especially Longmenshan fault, cut obviously the Moho discontinuity. The Xianshuihe fault, a typical strike-slip fault, has no obvious indication of cutting the Moho discontinuity, but has distinct low-velocity zone in different depths. 展开更多
关键词 Sichuan-Yunnan area SEISMICITY crustal block deep structure
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远场弱动载触发深部高应力煤层大巷冲击地压发生机制及防控机理 被引量:2
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作者 李家卓 彭瑞 +2 位作者 窦林名 杨科 解文豪 《采矿与安全工程学报》 北大核心 2025年第2期371-381,共11页
以陕西某矿一盘区煤层大巷为工程背景,综合采用现场监测、实验室试验和理论分析方法,研究了远场弱动载触发深部高应力盘区大巷围岩的失稳特征及诱冲机理。研究结果表明:大巷围岩力学环境受两盘区工作面回采影响,首先一盘区侧覆岩空间结... 以陕西某矿一盘区煤层大巷为工程背景,综合采用现场监测、实验室试验和理论分析方法,研究了远场弱动载触发深部高应力盘区大巷围岩的失稳特征及诱冲机理。研究结果表明:大巷围岩力学环境受两盘区工作面回采影响,首先一盘区侧覆岩空间结构呈“F”形,二盘区首采工作面回采后,大巷覆岩空间结构转化为双“F”形,随着两盘区其他工作面回采,大巷覆岩空间结构最终呈“T”形,在此过程中大巷围岩静应力水平持续增加,长期高静应力导致煤体损伤不断累积、强度持续劣化。在此期间,对处于等速蠕变阶段的煤样施加持续扰动,其声发射活动相比无扰动作用的煤样更为活跃,并将提前进入加速蠕变阶段,发生失稳破坏时煤样声发射的幅值、计数、能量相比无扰动作用下更加剧烈,且煤样承受的静应力水平越高,动载扰动对煤样损伤越显著,该损伤煤样再受弱动载扰动后发生非稳态破坏。现场表现为近场长期高静应力和频繁矿震联合作用导致煤岩体发生冲击地压的最小载荷降低,远场矿震衰减后的弱动载与高静载叠加超过了降低后的发生冲击地压时的最小载荷,此时煤岩体内剩余的能量超过发生冲击地压所需的最小能量,引起了大巷发生冲击地压。研究成果可为深部开拓和准备巷道(煤巷)冲击地压监测预警及防控提供理论基础。 展开更多
关键词 盘区大巷 覆岩空间结构 近场累积损伤 远场弱动载 诱冲机理
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ON PARAMETRIC MARCINKIEWICZ INTEGRALS RELATED TO BLOCK SPACES 被引量:1
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作者 WuHuoxiong ZhangPu 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2003年第3期258-266,共9页
In this paper,the L2-boundedness of a class of parametric Marcinkiewicz integral μρ Ω,h with kernel function Ω in B 0,0 q(S n-1) for some q>1,and the radial function h(x)∈l∞(Ls)(R +) for 1<s≤∞ are... In this paper,the L2-boundedness of a class of parametric Marcinkiewicz integral μρ Ω,h with kernel function Ω in B 0,0 q(S n-1) for some q>1,and the radial function h(x)∈l∞(Ls)(R +) for 1<s≤∞ are given.The Lp(Rn)(2≤p<∞) boundedness of μ *,ρ Ω,h,λ and μ ρ Ω,h,S with Ω in B 0,0 q(S n-1) and h(|x|)∈l∞(Ls)(R +) in application are obtained.Here μ *,ρ Ω,h,λ and μ ρ Ω,h,S are parametric Marcinkiewicz integrals corresponding to the Littlewood-Paley g* λ function and the Lusin area function S,respectively. 展开更多
关键词 Marcinkiewicz integral Littlewood-Paley g-function Lusin area integral block space l∞(Ls)(R +)
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老旧社区防灾更新建设管控——基于东京市防灾街区整备地区更新经验
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作者 马东辉 朱孟华 +2 位作者 费智涛 刘刚 王威 《上海城市规划》 北大核心 2025年第1期137-142,共6页
大量亟待更新的城市老旧社区是城市建设发展的重要议题,在地震灾害下呈现出高脆弱性、高暴露性和高损失的特性,老旧社区的防灾更新建设更显必要。首先总结东京市防灾街区整备地区建设的框架,明确“风险评估—地区划分—设施保障—建设... 大量亟待更新的城市老旧社区是城市建设发展的重要议题,在地震灾害下呈现出高脆弱性、高暴露性和高损失的特性,老旧社区的防灾更新建设更显必要。首先总结东京市防灾街区整备地区建设的框架,明确“风险评估—地区划分—设施保障—建设管控”的建设逻辑;然后介绍具体的更新措施,通过风险评估和地区识别高风险的更新区域,划分两种地区和5类用地功能区,提出地区防灾设施的配置要求,并通过用地、设施、建筑3类要素落实防灾管控要求;最后从地震风险的明晰、分类分区的特色引导、防灾设施保障、管控内容落实4个方面探讨对我国老旧社区建设的启示。 展开更多
关键词 防灾街区整备地区 地震灾害 老旧社区 更新建设 东京市
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Left bundle branch pacing cardiac resynchronization therapy vs biventricular pacing cardiac resynchronization therapy–time to write a requiem for biventricular pacing-cardiac resynchronization therapy
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作者 Akshyaya Pradhan Daljeet Saggu Monika Bhandari 《World Journal of Cardiology》 2025年第2期118-124,共7页
Cardiac resynchronization therapy(CRT)reduces heart failure(HF)hospitaliz-ations and all-cause mortality in patients with HF with reduced ejection fraction with left bundle branch(LBB)block.Biventricular pacing(BVP)is... Cardiac resynchronization therapy(CRT)reduces heart failure(HF)hospitaliz-ations and all-cause mortality in patients with HF with reduced ejection fraction with left bundle branch(LBB)block.Biventricular pacing(BVP)is considered the gold standard for achieving CRT;however,approximately 30%–40%of patients do not respond to BVP-CRT.Recent studies have demonstrated that LBB pacing(LBBP)produces remarkable results in CRT.In this meta-analysis,LBBP-CRT showed better outcomes than conventional BVP-CRT,including greater QRS duration reduction and left ventricular ejection fraction improvement,along with consistently lower pacing thresholds on follow-up.Additionally,there was a grea-ter reduction in New York Heart Association class and brain natriuretic peptide levels.This study contributes to the growing body of encouraging data on LBBP-CRT from recent years.With ongoing technological advancements and increasing operator expertise,the day may not be far when LBBP-CRT becomes the standard of care rather than the exception. 展开更多
关键词 Heart failure Left bundle branch block area pacing Narrow QRS New York Heart Association class Left ventricular ejection fraction
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延川南区块深部煤炭地下气化地质条件评价及有利区优选
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作者 李鑫 陈贞龙 +5 位作者 郭涛 高小康 肖翠 金晓波 吴财芳 王芳芳 《煤田地质与勘探》 北大核心 2025年第2期44-54,共11页
【目的和方法】煤炭地下气化(UCG)地质条件评价将极大降低其工程风险,科学选址则是UCG工程能否成功的先决条件。为研究延川南区块深部UCG地质条件评价和优选有利区域,对研究区2号煤层的煤岩煤质、煤层赋存、围岩、水文地质、构造等指标... 【目的和方法】煤炭地下气化(UCG)地质条件评价将极大降低其工程风险,科学选址则是UCG工程能否成功的先决条件。为研究延川南区块深部UCG地质条件评价和优选有利区域,对研究区2号煤层的煤岩煤质、煤层赋存、围岩、水文地质、构造等指标进行量化处理,利用TOPSIS法,对各开发区域进行数学评价和等级划分,最终形成有利区、较有利区以及潜在有利区的综合评价结果。【结果】结果表明:研究区2号煤层属于三角洲平原相沉积环境,大部分属于中煤级煤,焦煤、贫煤和瘦煤均有分布;平均水分和灰分平均含量较低,挥发分产率较高,硫分含量则是从低硫煤到高硫煤都有一定发育;煤层厚度较大,稳定性较好,平均夹矸层数和夹矸系数相对较小,煤层结构简单,属于稳定的中厚−厚煤层,煤体结构较完整。2号煤层的顶底板岩性多为泥岩类,围岩综合岩性指数较大,封闭性能好;总体断层分形维数值中等,断层发育程度简单,开发条件较好;研究区地表水部分发育,水文分形维数值中等,地下水封闭系数较大。【结论】整体而言,研究区2号煤层的资源条件和地质条件适合进行UCG工程实施。依据构造、埋深、河流和矿井边界等分布特征,结合地勘资料描述,将目的煤层划分为11个开发单元,有利区主要集中在北部,最有利区域是中北部的单元Ⅴ和Ⅲ,较有利区主要为Ⅰ、Ⅱ、Ⅳ、Ⅵ、Ⅶ、Ⅸ、Ⅹ,区域Ⅷ和Ⅺ为煤炭地下气化开发的潜在有利区。 展开更多
关键词 煤炭地下气化(UCG) 深部地质条件评价 TOPSIS法 有利区优选 延川南
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长江中游洲滩植被生长动态及其对水流阻力的影响 被引量:2
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作者 刘胜琪 夏军强 +2 位作者 石希 周美蓉 辛沛 《水资源保护》 北大核心 2025年第2期233-241,共9页
以长江中游洲滩典型水生植物芦苇为研究对象,构建了考虑淹水胁迫影响的芦苇生长模型及其生物量分层模型,提出了一种考虑芦苇生长动态的等效曼宁糙率计算方法,分析了不同洪水淹没条件和不同芦苇生长过程对等效曼宁糙率的影响,并建立了非... 以长江中游洲滩典型水生植物芦苇为研究对象,构建了考虑淹水胁迫影响的芦苇生长模型及其生物量分层模型,提出了一种考虑芦苇生长动态的等效曼宁糙率计算方法,分析了不同洪水淹没条件和不同芦苇生长过程对等效曼宁糙率的影响,并建立了非淹没状态下等效曼宁糙率与芦苇地上生物量、相对淹没度的经验计算公式。结果表明:考虑淹水胁迫影响的芦苇生长模型可以较好地模拟芦苇地上生物量和形态参数的变化过程,模拟结果纳什效率系数为0.85~0.94;芦苇生物量和阻水面积有相似的垂向分布规律,以相对高度0.3为界限,芦苇茎阻水面积上小下大,叶阻水面积下小上大,在相对高度0.7以下芦苇总阻水面积和地上生物量近似呈均匀分布;最大等效曼宁糙率计算值约为0.300,淹水胁迫影响下芦苇地上生物量减少,导致同水深条件下等效曼宁糙率值减小10.0%~29.1%。 展开更多
关键词 芦苇生长 等效曼宁糙率 生物量 阻水面积 相对淹没度 长江中游
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层积共生:居住型历史街区遗产价值辨识——以西安明城区回坊片区为例
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作者 李昊 董蓉莲 刘珈毓 《城市设计》 2025年第1期62-71,共10页
围绕“原真”与“完整”、“宏大”与“日常”,分析居住型历史街区在遗产价值辨识方面存在的问题,结合建成遗产与历史街区的理论发展,研判西安明城区回坊片区现实状况,对回坊片区建成遗产的总体特征进行辨识,探讨回坊片区在历史场所谱... 围绕“原真”与“完整”、“宏大”与“日常”,分析居住型历史街区在遗产价值辨识方面存在的问题,结合建成遗产与历史街区的理论发展,研判西安明城区回坊片区现实状况,对回坊片区建成遗产的总体特征进行辨识,探讨回坊片区在历史场所谱系和文化基因共生方面的价值属性。 展开更多
关键词 层积 共生 居住型历史街区 遗产价值 回坊片区
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扬子板块西南缘早前寒武纪地质演化:来自撮科元古宙变沉积岩碎屑锆石U-Pb年龄、Hf-O同位素的制约
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作者 高嘉敏 谢士稳 +3 位作者 刘倩 王舫 陶鹏 龙涛 《岩石学报》 SCIE EI CAS 北大核心 2025年第1期304-320,共17页
扬子板块的太古宙-古元古代基底出露十分有限,制约了对扬子早前寒武纪地质演化的认识。本次研究对扬子板块西南缘撮科地区的大红山群和昆阳群变沉积岩开展了碎屑锆石原位U-Pb年龄、Hf-O同位素及微量元素研究。测年结果显示,大红山群谐... 扬子板块的太古宙-古元古代基底出露十分有限,制约了对扬子早前寒武纪地质演化的认识。本次研究对扬子板块西南缘撮科地区的大红山群和昆阳群变沉积岩开展了碎屑锆石原位U-Pb年龄、Hf-O同位素及微量元素研究。测年结果显示,大红山群谐和锆石年龄分布于3092~1786Ma之间,最年轻碎屑锆石年龄为1786Ma,限定大红山群最大沉积时代为古元古代晚期。昆阳群谐和锆石年龄分布于2874~1031Ma之间,最年轻碎屑锆石年龄为1031Ma,表明昆阳群最大沉积时代为中元古代晚期。除少量较年轻锆石(<1.75Ga)外,昆阳群和大红山群具有相似的年龄分布特征,两个主要的年龄峰为2.0~1.85Ga和2.4~2.2Ga。尽管古元古代碎屑锆石的年龄峰与撮科地区已报道的古元古代岩浆活动期次一致,但仅有少部分碎屑锆石的Hf-O同位素特征与撮科古元古代岩浆岩相似,大多数碎屑锆石Hf-O同位素组成与加拿大Rae克拉通古元古代变沉积岩中碎屑锆石相似,暗示古元古代碎屑物质可能仅少部分来自撮科地区已识别的古元古代岩浆岩,而大部分可能来自与Rae克拉通发育的古元古岩浆岩相似的源区。大红山群和昆阳群中1.9~1.03Ga的碎屑锆石可能来自扬子西南缘发育的古元古代晚期-中元古代晚期岩浆岩。结合前人的资料,我们认为我国撮科和越南北部的Phan Si Pan带经历了与加拿大Rae克拉通相似的古元古代演化过程,支持2.4~2.3Ga扬子西南缘卷入Arrowsmith造山事件,并与Rae克拉通一起参与哥伦比亚超大陆聚合过程的认识。 展开更多
关键词 扬子西南缘 撮科地区 哥伦比亚超大陆 大红山群和昆阳群 碎屑锆石
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多宝山窝里河一带寒武纪安山质火山活动及“兴安地块”属性
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作者 付俊彧 李仰春 +5 位作者 崔丹丹 庞雪娇 杨晓平 杨浩 那福超 孙巍 《地质学报》 北大核心 2025年第9期2948-2962,共15页
内容提要:多宝山铜钼金矿集区早古生代成矿地质背景及“兴安地块”的构造属性问题的争议,制约了区域找矿方向的确定。本文采用岩石地球化学、锆石U-Pb年代学方法,研究了多宝山地区窝里河一带出露的一套变质安山质晶屑凝灰岩,以探讨其早... 内容提要:多宝山铜钼金矿集区早古生代成矿地质背景及“兴安地块”的构造属性问题的争议,制约了区域找矿方向的确定。本文采用岩石地球化学、锆石U-Pb年代学方法,研究了多宝山地区窝里河一带出露的一套变质安山质晶屑凝灰岩,以探讨其早古生代早期形成的构造背景及“兴安地块”的构造属性。作者随机测试了变质安山质晶屑凝灰岩60颗锆石,获得^(206)Pb/^(238)U加权平均年龄为502.6±2.7Ma(n=57,MSWD=1.4),表明其形成于寒武纪苗岭世晚期。变质安山质晶屑凝灰岩SiO_(2)平均含量59.02%,具有高Al_(2)O_(3)(平均16.67%),较高的MgO(平均4.06%),中等的TiO_(2)(平均0.75%)含量;里特曼指数(σ)平均为1.81,属钙碱性系列火山岩。岩石Cr(平均104×10^(-6))、Ni(平均为64×10^(-6))、Sr(平均为414×10^(-6))含量也较高,富集大离子亲石元素Rb、Ba、Th、U,亏损高场强元素Nb、P、Ti,形成于大陆边缘弧构造背景。岩浆源自俯冲板片的熔体及受俯冲板片熔体和脱水流体交代的新元古代亏损的地幔楔。结合新近地质调查研究成果及区域地质建造特点,认为沿“兴安地块”东南缘多宝山—阿荣旗—海勒斯台一线发育一套具有一定规模的显示陆缘岩浆弧特点的寒武纪苗岭世晚期火山-沉积建造,有必要建立一个单独的地质填图单位;多宝山地区的铜山组有必要进一步解体。“额尔古纳地块”与“兴安地块”于新元古代晚期碰撞拼合形成“额尔古纳-兴安联合地块”后,至少在约570~514Ma期间为被动大陆边缘背景,地块相对稳定;516Ma山根拆沉,软流圈上涌形成陆内裂谷;随着应力的积累,503Ma诱发“额尔古纳-兴安联合地块”东南侧古亚洲洋分支的北西向俯冲,从而形成陆缘岩浆弧;从此,“兴安地块”逐渐遭到破坏并转变为古生代弧-盆系,控制了区域铜钼金成矿地质背景。 展开更多
关键词 多宝山窝里河 锆石年龄 寒武纪苗岭世晚期 “兴安地块” 陆缘弧
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拉萨地块晚古生代冰期沉积特征研究——以申扎地区为例
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作者 何柯衡 许欢 +6 位作者 安显银 刘高政 杜研 丁家翔 夏磊 苑婷媛 郑洪波 《沉积学报》 北大核心 2025年第3期976-995,共20页
【目的】晚古生代冰期作为显生宙以来持续时间最长、影响范围最广、地质记录最丰富的冰期事件,记录了完整的冰室—温室气候转变过程,对于我们理解地球气候演变具有重要意义。虽然前人针对晚古生代冰期的时空演化、控制因素等开展了大量... 【目的】晚古生代冰期作为显生宙以来持续时间最长、影响范围最广、地质记录最丰富的冰期事件,记录了完整的冰室—温室气候转变过程,对于我们理解地球气候演变具有重要意义。虽然前人针对晚古生代冰期的时空演化、控制因素等开展了大量研究,但对于拉萨地块晚古生代冰期特别是冰期沉积记录却知之甚少,相关研究亟待加强。【方法】选取拉萨地块申扎地区晚古生代地层开展1∶200比例尺的剖面实测,对冰期发育层位进行沉积岩相及岩相组合划分,运用沉积构型分析方法来判别沉积环境,恢复冰川沉积体系。【结果】拉萨地块晚古生代冰期记录主要发育在拉嘎组,时代为晚石炭世—早二叠世。针对拉嘎组冰期沉积,共划分出20种岩相和16类典型岩相组合,识别出了6类冰期沉积环境,包括浅海陆棚、基线扇、冰底、冰河、冰湖和冰水扇。【结论】拉萨地块申扎地区晚古生代冰期经历了早期海洋型冰川向晚期陆地型冰川的转变,指示全球晚石炭世至早二叠世整体气候逐渐变暖的趋势,与全球晚古生代冰期演化特征一致。 展开更多
关键词 拉萨地块 申扎地区 晚古生代冰期 岩相 沉积环境 冰川演化
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基于非均衡能力路网的装车地多模式列车组合开行方案优化
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作者 李冰 程艳 轩华 《运筹与管理》 北大核心 2025年第1期34-40,共7页
研究一类契合非均衡能力路网的装车地多模式列车组合开行问题,最大限度降低因铁路区段牵引定数不统一、通行能力不一致给运输组织工作带来的影响。首先,研究基于最小牵引定数的恒定列车重量方案,给出三种装车地列车组合开行模式,并以装... 研究一类契合非均衡能力路网的装车地多模式列车组合开行问题,最大限度降低因铁路区段牵引定数不统一、通行能力不一致给运输组织工作带来的影响。首先,研究基于最小牵引定数的恒定列车重量方案,给出三种装车地列车组合开行模式,并以装卸车站停留车小时、沿途技术站改编车小时以及线路运能损失换算车小时最小为目标,考虑密集装车能力限制和车流组织的唯一性限制,构造基于恒定列车重量的列车组合开行方案模型;进而,研究基于换重站补减轴的动态编组列车方案,给出两种装车地列车组合开行模式,考虑换重车小时损失,构造基于端点换重的列车组合开行方案模型。最后,以海拉尔站滨州线通道为背景,对恒定列车重量开行方案与端点换重列车开行方案进行对比分析,并形成基于恒定重量与动态编组协同的列车组合开行方案,以最大限度降低车小时损失,充分利用非均衡路网铁路通道运能。 展开更多
关键词 装车地 铁路区段 牵引定数 端点换重 直达列车
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额尔古纳地块北段霍洛台地区辉绿岩锆石U-Pb定年、岩石地球化学特征和构造背景 被引量:1
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作者 孙永刚 李碧乐 +3 位作者 谢实学 靳皇玉 凌世伟 李焕纪 《世界地质》 2025年第1期22-34,共13页
为探讨大兴安岭地区早白垩世大规模岩浆活动形成的地球动力学机制,笔者选取大兴安岭额尔古纳地块北段霍洛台地区辉绿岩为研究对象,通过对霍洛台地区辉绿岩进行岩石地球化学特征及锆石U-Pb定年的研究,查明其形成时代、岩石成因和构造背景... 为探讨大兴安岭地区早白垩世大规模岩浆活动形成的地球动力学机制,笔者选取大兴安岭额尔古纳地块北段霍洛台地区辉绿岩为研究对象,通过对霍洛台地区辉绿岩进行岩石地球化学特征及锆石U-Pb定年的研究,查明其形成时代、岩石成因和构造背景。LA-ICP-MS锆石U-Pb定年分析结果表明霍洛台地区辉绿岩的加权平均年龄为(135.1±3.6)Ma,代表辉绿岩的结晶年龄为早白垩世。全岩地球化学数据显示,霍洛台辉绿岩具有低w(SiO_(2))(48.84%~52.11%),高w(MgO)(5.13%~6.85%)和w(Fe_(2)O_(3))(7.45%~8.60%)的特征;其Eu异常不明显或具有弱的负异常特征(δEu=0.83~1.06),富集大离子亲石元素(如Ba、Sr和K),亏损高场强元素(如Zr、Ta、Nb和Th)。霍洛台地区辉绿岩受到分离结晶、地壳混染和堆晶作用的影响有限。Nb/Yb-Th/Yb图解显示霍洛台地区辉绿岩落在俯冲改造的岩石圈地幔起源的原始镁铁质熔体区域,Th/Nb-Ba/Th和Th/Yb-Ba/La图解显示霍洛台地区辉绿岩的岩浆源区被板片流体改造,La/Nb-La/Ba图解显示霍洛台地区辉绿岩的岩浆源区为岩石圈地幔源区。上述地球化学特征表明霍洛台地区辉绿岩起源于俯冲板片流体交代的岩石圈地幔源区。结合前人研究成果,认为大兴安岭额尔古纳地块北段霍洛台地区辉绿岩的形成与古太平洋板块的回卷过程密切相关。 展开更多
关键词 辉绿岩 地球化学特征 构造背景 锆石U-PB定年 早白垩世 霍洛台地区 额尔古纳地块
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管壳式换热器间隙与折流板参数的影响分析
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作者 蔡尚峰 闫佳兵 +1 位作者 周利伟 王成 《舰船科学技术》 北大核心 2025年第20期140-145,共6页
管壳式换热器作为舰船核动力装置重要的换热传导装置,研究壳侧各流程的热流特性,有助于剖析其相互作用机制,并对管壳换热器进行优化设计。本文基于计算流体动力学(CFD)方法,对具有板-壳和板-管间隙、折流板间距和缺口高度的传统单段折... 管壳式换热器作为舰船核动力装置重要的换热传导装置,研究壳侧各流程的热流特性,有助于剖析其相互作用机制,并对管壳换热器进行优化设计。本文基于计算流体动力学(CFD)方法,对具有板-壳和板-管间隙、折流板间距和缺口高度的传统单段折流板管壳式换热器壳程热流特性进行系列仿真对比分析研究。研究发现,板-壳间隙和板-管间隙最大允许值下,旁路泄漏流程A和E占总壳程流通量的34%~40%,平均流速分别降低23%和30%,表面热交换率系数分别降低了35%和13%;阻滞区受折流板间距和缺口高度的共同影响,当折流板之间通流截面面积大于折流板缺口的截面面积时,阻滞区增加;阻滞区相对宽度在H_w/L_b≥0.85时为16%~18%,且变化较小;而当,H_w/L_b<0.85时,其相对宽度急剧增加至约40%。 展开更多
关键词 管壳式换热器 泄漏流 折流板参数 热流特性 阻滞区
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曲面过水断面非正交阻水计算方法
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作者 左建 李立平 +1 位作者 卜慧 朱迪 《长江科学院院报》 北大核心 2025年第10期9-14,23,共7页
阻水比是衡量涉水工程建设对河道行洪影响程度的重要指标。对蜿蜒型、游荡型河道而言,其过水断面为曲面,常规的河道阻水计算方法无法适用。结合非正交于河道过水断面的工程线路,通过设置水流流向偏角阈值,将曲面过水断面划分为多个平面... 阻水比是衡量涉水工程建设对河道行洪影响程度的重要指标。对蜿蜒型、游荡型河道而言,其过水断面为曲面,常规的河道阻水计算方法无法适用。结合非正交于河道过水断面的工程线路,通过设置水流流向偏角阈值,将曲面过水断面划分为多个平面过水断面,提出了曲面过水断面非正交阻水计算公式,并将其应用于武汉—松滋高速公路东荆河大桥阻水比计算中。计算结果表明,将东荆河大桥跨越处曲面过水断面划分为116个局部过水断面情况下,其阻水总面积为975 m^(2),阻水比为4.24%;通过经验公式和二维数学模型分析了阻水比计算的合理性,根据阻水比和Henderson公式计算河道内水位壅高值为1 mm,二维数值模型计算桥墩位置处水位壅高值为1~3 mm。考虑经验公式采用的是全断面平均流速,故其计算的水位壅高值略小于二维水流数学模型计算的桥墩位置处局部水位壅高值是合理的。通过划分局部过水断面的方式计算曲面河道非正交工程的阻水面积及阻水比是可行的,可为水行政主管部门审批涉河建设工程的行洪影响提供参考。 展开更多
关键词 阻水比 曲面河道断面 局部过水断面 阻水面积 非正交 行洪影响
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