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Ammonoid Succession of Setorym River (Verkhoyansk Area) and Problem of Permian-Triassic Boundary in Boreal Realm 被引量:1
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作者 Yuri D Zakharov Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Sciences, Prospect Stoletiya Vladivostoka 159, Russia 《Journal of China University of Geosciences》 SCIE CSCD 2002年第2期107-123,共17页
The presence of a single Otoceras species ( O. boreale ), morphologically very variable, at the base of the Nekuchan Formation in Verkhoyansk, we believe, is to be obvious. Some morphological evidence leaves no ... The presence of a single Otoceras species ( O. boreale ), morphologically very variable, at the base of the Nekuchan Formation in Verkhoyansk, we believe, is to be obvious. Some morphological evidence leaves no doubt that two described morphs of O. boreale are a strictly corresponding sexual dimorphic pair. It is very likely that Kummel's idea that Canadian O. concavum Tozer is an invalid species is truthful, considering the range of variability seen in larger Siberian and Himalayan Otoceras fauna. Just above the upper Tatarian Imtachan Formation, the six stages of ammonoid succession can be recognized within the lower part of the Nekuchan Formation in the Setorym River Section: (a) Otoceras boreale ; (b) Otoceras boreale-Tompophiceras pascoei ; (c) Otoceras boreale-Tompophiceras pascoei- Aldanoceras ; (d) Tompophiceras pascoei-Otoceras boreale-Aldanoceras ; (e) Tompophiceras morpheous-T. pascoei-Aldanoceras ; (f) Tompophiceras morpheous-T. pascoei-Wordieoceras domokhotovi-Ophiceras transitorium; (g) Tompophiceras morpheous-T. pascoei, corresponding to the Otoceras boreale and Tompophiceras morpheous zones. In spite of the domination of Otocerataceae or Xenodiscaceae in both of these zones and the presence of some Permian type conodonts in the lower part of the Otoceras boreale Zone, they seem to be early Induan in age on the basis of the following arguments: (1) in contrast to the underlying regressive type sediments of the Upper Tatarian Imtachan Formation, both the Otoceras boreale and the Tompophiceras morpheous zones of the lowermost part of the Nekuchan Formation correspond to the single transgressive cycle; (2) typical early Induan ammonoids ( Ophiceras and Wordieoceras ) have been recognized in the Tompophiceras morpheous zone; (3) all described ammonoid succession stages (a-g) are characterized by very gradual changes and therefore correspond to the different parts of the single zone or to the different zones of the same stage, but not to the different systems (Permian and Triassic); (4) elsewhere in the Boreal realm (Arctic Canada), the conodont index species for the base of the Triassic, Hindeodus parvus , has been reported from the Otoceras boreale Zone. A new scheme of the phylogeny for the Otocerataceae and its Induan Olenekian offspring (Araxceratidae- Otoceratidae- Vavilovitidae n.fam.-Proptychitidae-Arctoceratidae) and Xenodiscaceae is offered. 展开更多
关键词 Siberia Verkhoyansk permian-triassic boundary Otoceras beds.
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碳中和目标下中国天然气工业进展、挑战及对策 被引量:18
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作者 邹才能 林敏捷 +10 位作者 马锋 刘翰林 杨智 张国生 杨依超 关春晓 梁英波 王影 熊波 于豪 余平 《石油勘探与开发》 EI CAS CSCD 北大核心 2024年第2期418-435,共18页
天然气在21世纪中叶将迈入“鼎盛期”,“天然气时代”正在到来。回顾全球天然气工业历程,梳理美国页岩革命启示,总结中国天然气发展历史与成果进展,分析天然气在能源绿色低碳转型中的地位与挑战,提出当前和未来中国天然气工业的发展对... 天然气在21世纪中叶将迈入“鼎盛期”,“天然气时代”正在到来。回顾全球天然气工业历程,梳理美国页岩革命启示,总结中国天然气发展历史与成果进展,分析天然气在能源绿色低碳转型中的地位与挑战,提出当前和未来中国天然气工业的发展对策。中国天然气工业经历了起步、增长、跨越3个发展阶段,已成为世界第4大天然气生产国与第3大消费国;天然气勘探开发理论技术取得重大成就,为储量产量规模增长提供了重要支撑。碳中和目标下,推动绿色可持续发展,天然气工业发展挑战与机遇并存。天然气低碳优势显著,“气电调峰”助力新能源发展;同时,开采难度与成本加大等问题更突出。为保障国家能源安全,实现经济社会与生态环境和谐共生,碳中和进程中,立足“统筹布局、科技创新;多能互补、多元融合;灵活高效、优化升级”,完善产供储销体系建设,加速推动天然气工业发展:①加大天然气勘探开发力度,规划部署重点勘探开发领域,突破关键理论,强化技术攻关,持续支撑增储上产;②推进天然气绿色创新发展,突破新技术,拓展新领域,融合新能源;③优化天然气供需转型升级,加大管道气、液化天然气布局和地下储气库建设,建立储备体系,提升应急调节能力和天然气一次能源消费比例,助力能源消费结构转型,实现资源利用低碳化、能源消费清洁化。 展开更多
关键词 碳中和 天然气 页岩气 致密气 煤层气(煤岩气) 新能源 能源转型
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Geological event sequences of the Permian-Triassic transition recorded in the microfacies in Meishan section 被引量:11
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作者 CAO ChangQun ZHENG QuanFeng 《Science China Earth Sciences》 SCIE EI CAS 2009年第10期1529-1536,共8页
The microfacies sequence in the key interval of Beds 24―29 of the Meishan section comprehensively recorded the geological events during the Permian-Triassic transition, including the anoxia, storm disturbance, hard-g... The microfacies sequence in the key interval of Beds 24―29 of the Meishan section comprehensively recorded the geological events during the Permian-Triassic transition, including the anoxia, storm disturbance, hard-ground/firm-ground form, volcanic eruption, weathering input, and microbialite development. This investigation of event sequences on the microfacies provided synthetically some clues to clarifying the previously proposed mechanisms of the end-Permian extinction. The deposit succession in Bed 24 of the Changxing Formation was developed dominantly with organic-rich lamina, but interrupted intermittently by storm disturbances. It indicates characteristically a stagnated, stratified and anoxic ocean during the latest Permian. The latest Permian transgression occurred rapidly at the top of Bed 24d and was characterized by the hard-ground interface. Abundant clay mineral of illite indicates the occurrence of persistent weathering of continental volcanics and then buried in ocean throughout this key Permo-Triassic transitional interval. However, the "boundary ash clay" of Bed 25 yielding normal grading of hyaloclastite was the result of precipitation of volcanic dusts. The firm-ground substrate in Unit 27-2 was lithe and excavated intensively by trace fossil Glossifungites; it means also the occurrence of the earliest Triassic rapid transgression and coincides with the first appearance of conodont Hindeodus parvus. Dune-shaped microbialite in Unit 27-5 defines biostrati-graphically that its development, especially in the carbonate platform of South China, should corre-spond to the earliest Triassic; and it also indicates the final episode of the end-Permian extinction event. 展开更多
关键词 MEISHAN permian-triassic transitION MICROFACIES event SEQUENCES
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A comparison of the biological,geological events and environmental backgrounds between the Neoproterozoic-Cambrian and Permian-Triassic transitions 被引量:10
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作者 ShuZhong Shen MaoYan Zhu +3 位作者 XiangDong Wang GuoXiang Li ChangQun Cao Hua Zhang 《Science China Earth Sciences》 SCIE EI CAS 2010年第12期1873-1884,共12页
The Neoproterozoic-Cambrian(N-C) and Permian-Triassic(P-T) transitions have been regarded the two most critical transitions in earth history because of the explosive biological radiation in the early Cambrian(the Camb... The Neoproterozoic-Cambrian(N-C) and Permian-Triassic(P-T) transitions have been regarded the two most critical transitions in earth history because of the explosive biological radiation in the early Cambrian(the Cambrian Explosion) and the largest mass extinction at the end-Permian.Previous studies suggest that these two critical transitions showed certain comparability in major evolutionary events.In other words,a series of biological,geological,and geochemical events that had happened in the N-C transition occurred repeatedly during the P-T transition.Those events included continental re-configuration related to the deep mantle dynamics,global-scale glaciations,large C-,Sr-,and S-isotope perturbations indicating atmospheric and oceanic changes,abnormal precipitation of carbonates,and associated multiple biological radiations and mass extinctions.The coupling of those events in both N-C and P-T transitions suggests that deep mantle dynamics could be a primary mechanism driving dramatic changes of environment on the earth's surface,which in turn caused major biological re-organizations.A detailed comparison of those events during the two critical transitions indicates that despite their general comparability,significant differences do exist in magnitude,duration,and frequency.The supercontinent Rodinia began to rift before the Snowball Earth time.By contrast,the supercontinent Pangea entered the dispersal stage after the greatest glaciation from the Late Carboniferous to Cisuralian.Quantitative data and qualitative analyses of different fossil groups show a more profound mass extinction during the N-C transition than at the end-Permian in terms of ecosystem disruption.This is indicated by the disappearance of the whole Ediacaran biota at the N-C boundary.The subsequent appearances of many new complex animals at phylum level in the early Cambrian mark the establishment of a brand new ecosystem.However,the end-Permian mass extinction is manifested mainly by the extinction of many different taxa at class and order levels.Although it caused the extinction of 95% of marine species and 75% of terrestrial species as well as complete cessation of coal and reef deposits after the mass extinction,this high-level biological re-organization still occurred within an established ecosystem,however drastic it may seem.Survived or Lazarus taxa re-occupied the existing ecospace in a relatively short duration after the end-Permian mass extinction.C-isotope excursions display large perturbations during both transitions,yet also in different magnitudes and frequencies,which suggest different atmospheric and oceanic conditions.The recurrent geological and geochemical events as well as the coupled major biological turnovers during the two transitions provide new clues to understanding the interplays among the earth-life system.Thus,it is essential to carry out multidisciplinary studies from the deep internal system to the surface of the Earth as a whole in order to unravel the interactions of different spheres of the earth. 展开更多
关键词 Neoproterozoic-Cambrian permian-triassic transition BIOLOGICAL EVENTS geological EVENTS ENVIRONMENTAL background
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Two episodic changes of trace fossils through the Permian-Triassic transition in the Meishan cores,Zhejiang Province 被引量:6
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作者 ZHAO XiaoMing TONG JinNan 《Science China Earth Sciences》 SCIE EI CAS 2010年第12期1885-1893,共9页
Six ichnogenera,Chondrites,Palaeophycus,Planolites,Rhizocorallium,Skolithos,and Thalassinoides,were identified from the drilling cores near the Global Stratotype Section and Point(GSSP) of Permian-Triassic boundary at... Six ichnogenera,Chondrites,Palaeophycus,Planolites,Rhizocorallium,Skolithos,and Thalassinoides,were identified from the drilling cores near the Global Stratotype Section and Point(GSSP) of Permian-Triassic boundary at Meishan,Zhejiang Province.The ichnological indices,including abundance,bioturbation index,and disturbed depth of trace fossils,show two episodes of intense changes near the Permian-Triassic Boundary(PTB).Episode I occurred in Beds 25-27b when the ecologically complicate forms such as Chondrites,Skolithos,Rhizocorallium,and Thalassinoides disappeared hereafter,the bioturbation index reduced from 1-5 to 1-3,and the disturbed depth declined from 5-66 to 2-5 cm.Episode II took place at the base of Bed 33 with the disappearance of Palaeophycus and Planolites,and subsequent absence of trace fossils and bioturbation till the middle-upper part of Bed 41 when the disturbed structures reoccurred,but they are only tiny Planolites and the bioturbation index was never higher than 3 and the disturbed depth less than 4 mm.Episode I shows an intense change,corresponding to the main stage of the end-Permian mass extinction,whereas Episode II is relatively weak,corresponding to the epilogue of the mass extinction of trace makers in the Early Triassic.Subsequently,ichnofossils were dominated by surface tracks in simple ecological habit and structures.This phenomenon indicates that the Early Triassic benthonic fauna is changed from sessile benthic system to mobile benthic system after the end-Permian mass extinction.In other words,the evolution of the trace fossils across the Permian-Triassic transition had an episodic process similar to the body fossils.In addition,the change of ichnofabrics is well coincided with the negative excursion of carbon isotopes and the expansion of cyanobacteria.As the results of physical and biogenic processes,trace fossils provided unique materials for the study of the biotic and environmental events,as well as their coupling evolution through the great Permian-Triassic transition. 展开更多
关键词 trace fossils bioturbation index disturbed depth the permian-triassic transition two episodic evolution Meishan cores
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The microfacies and sedimentary responses to the mass extinction during the Permian-Triassic transition at Yangou Section, Jiangxi Province, South China 被引量:4
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作者 TIAN Li TONG JinNan +5 位作者 SUN DongYing XIONG YanLin WANG ChengGang SONG HaiJun SONG HuYue HUANG YunFei 《Science China Earth Sciences》 SCIE EI CAS 2014年第9期2195-2207,共13页
A Permian-Triassic(P-Tr) boundary section of continuous carbonate facies, which well recorded the biotic and environmental processes through the great P-Tr transition in the shallow non-microbialite carbonate facies, ... A Permian-Triassic(P-Tr) boundary section of continuous carbonate facies, which well recorded the biotic and environmental processes through the great P-Tr transition in the shallow non-microbialite carbonate facies, has been studied in Yangou, Leping County, Jiangxi Province. The P-Tr sequence is well correlated with the Meishan section according to the conodont biostratigraphy and the excursion of carbon isotopes. A series of high-resolution thin-sections from the P-Tr boundary carbonate rocks at the Yangou section are studied to explore the interrelation between environmental change and biological evolution during the transitional time. Six microfacies have been identified based upon the observation of the thin-sections under a microscope on the grains and matrix and their interrelation. Combined with the data of fossils and carbon isotopes, Microfacies 4(MF-4), coated-grain-bearing foraminifer oolitic sparitic limestone, and Microfacies 6(MF-6), dark shelly micritic limestone, should be the different responses to the two episodes of mass extinction and environmental events that can be correlated throughout South China and even over the world. The oolitic limestone of MF-4 is the first finding from the latest Permian strata in South China and it might be a proxy of an unusual environmental condition of high pCO2, low sulfate concentration and of microbial blooming in the aftermath of the latest Permian mass extinction. The micritic limestone of MF-6 containing rich micro-gastropods and ostracods probably represents the blooming event of disaster taxa in the earliest Triassic environment. The microfacies analysis at the Yangou section can well reveal the episodic process of the biological evolution and environmental change in the shallow non-microbialite carbonate facies throughout the great P-Tr transition, thus the Yangou section becomes an important complement to the Meishan section. 展开更多
关键词 permian-triassic transition MICROFACIES mass extinction sedimentary response Yangou Jiangxi Province
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The transition to turbulent fluidization in a gas-solid fluidized bed operating from ambient temperature to 1600℃
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作者 Qingjin Zhang Liangliang Fu +1 位作者 Guangwen Xu Dingrong Bai 《Particuology》 SCIE EI CAS CSCD 2024年第10期111-124,共14页
Turbulent fluidized bed proves effective in industrial processes due to superior heat and mass transfer and chemical reaction performance. However, understanding the transition to turbulent fluidization remains limite... Turbulent fluidized bed proves effective in industrial processes due to superior heat and mass transfer and chemical reaction performance. However, understanding the transition to turbulent fluidization remains limited, especially at temperatures exceeding 1000 ℃, making it challenging to develop high-temperature fluidized bed applications. This paper presents an experimental investigation on the turbulent fluidization onset velocity (U_(c)), measured in a 30 mm diameter bed using corundum particles with average diameters from 0.68 mm to 1.58 mm in temperatures from ambient to 1600 ℃. Experimental results reveal that U_(c) increases with temperature up to 600 ℃, stabilizes within the 600–1200 ℃ range, and then decreases above 1200 ℃, demonstrating the varying relative significance of hydrodynamic and interparticle forces at different temperatures. To help design and operate high-temperature applications of turbulent fluidization, we developed U_(c) correlations based on experimental data from both literature sources and this study, covering temperatures of up to 1600 ℃ and particles of Groups A to D. 展开更多
关键词 High-temperature fluidized beds Turbulent fluidization transition velocity Pressure fluctuations Hydrodynamic forces Interparticle FORCES
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橡胶混凝土道床车致振动能量俘获研究
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作者 李政 金浩 孙博旭 《铁道标准设计》 北大核心 2024年第9期53-59,共7页
随着城市轨道交通运营里程的不断增加,为保证运营安全,需对轨道等结构进行健康监测。目前,既有监测传感器的供电方式主要采用外部市电或蓄电池。如何将列车运行产生的振动能量俘获并用于监测传感器供电,已经成为近些年的研究热点。针对... 随着城市轨道交通运营里程的不断增加,为保证运营安全,需对轨道等结构进行健康监测。目前,既有监测传感器的供电方式主要采用外部市电或蓄电池。如何将列车运行产生的振动能量俘获并用于监测传感器供电,已经成为近些年的研究热点。针对橡胶混凝土道床,设计了一种全新的球型俘能器。通过构建列车荷载作用下橡胶混凝土道床的计算模型,对垂向位移、应力、电压、总电能等指标进行分析。主要结论如下:(1)采用阵列形式将球型俘能器埋入橡胶混凝土道床,最优位置在轨枕之下5 mm;(2)在6 m长橡胶混凝土道床范围内布设10个俘能器,一辆8节编组A型列车驶过可产生毫焦级别的电能,若按照5 min发车间隔估算,1 h俘获总电能122.4 mJ;(3)橡胶混凝土道床较普通混凝土道床更有利于能量俘获,当橡胶含量为10%时,道床内部俘能器阵列所俘获的总电能较普通混凝土提高5%,应力等力学性能指标也在安全范围内。 展开更多
关键词 城市轨道交通 道床 橡胶混凝土 压电效应 能量俘获
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路桥过渡段双块式无砟轨道道床板上拱整治方案
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作者 任西冲 《铁道建筑》 北大核心 2024年第6期43-49,共7页
针对路桥过渡段连续型双块式无砟轨道端梁位置道床板上拱病害,建立理论分析模型,研究了层间黏结状态和端梁支承条件对道床板上拱变形的影响规律;提出五种植筋方案,并对比分析了各方案的整治效果。结果表明:整体上,道床板在路基侧距离端... 针对路桥过渡段连续型双块式无砟轨道端梁位置道床板上拱病害,建立理论分析模型,研究了层间黏结状态和端梁支承条件对道床板上拱变形的影响规律;提出五种植筋方案,并对比分析了各方案的整治效果。结果表明:整体上,道床板在路基侧距离端梁中心10 m范围内上拱,最大上拱位置距离端梁中心约3 m;随着层间抗拉和抗剪强度增加,道床板最大垂向位移呈非线性减小趋势,层间黏结强度显著抑制了道床板的上拱变形;层间摩擦因数以及支承层、级配碎石、AB组填料造成的端梁侧向支承刚度变化对道床板上拱变形的影响相对较小;在距离端梁20 m范围以外植筋对道床板上拱变形的限制较小,增加路基侧距离端梁10 m范围内植筋可以明显减小道床板上拱变形。 展开更多
关键词 高速铁路 路桥过渡段 双块式无砟轨道 道床板垂向位移 影响规律 植筋方案
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城市轨道交通工程铺轨施工技术要点分析
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作者 郭海建 《工程技术研究》 2024年第4期67-69,共3页
城市轨道交通工程铺轨施工是轨道交通建设过程中至关重要的一环,直接关系工程质量和运营安全。轨道交通工程铺轨施工建设不仅要确保轨道交通建设顺利进行,更要保障广大乘客的出行安全。文章围绕城市轨道交通工程铺轨施工进行研究,重点... 城市轨道交通工程铺轨施工是轨道交通建设过程中至关重要的一环,直接关系工程质量和运营安全。轨道交通工程铺轨施工建设不仅要确保轨道交通建设顺利进行,更要保障广大乘客的出行安全。文章围绕城市轨道交通工程铺轨施工进行研究,重点阐述了城市轨道交通工程铺轨施工技术要点,包括施工准备、合理选择铺轨方式及道床混凝土浇筑等,旨在提升城市轨道交通施工工艺和质量,更好地促进城市轨道交通工程的建设发展。 展开更多
关键词 城市轨道 铺轨施工技术 道床
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城市轨道交通不同道床形式下轨道病害分析及经验总结
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作者 陈宁 曹利琪 +3 位作者 郭磊 李达 马为 史见阳 《中国高新科技》 2024年第12期140-142,共3页
现阶段,我国城市轨道交通不断发展,城市地铁建设中越来越离不开道床的建设,不同的道床形式得到了广泛应用,文章以城轨交通中不同道床形式下的轨道病害为主要研究对象,总结养护经验,为相关工作提供参考。
关键词 城市轨道交通 道床形式 轨道病害 养护维修
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预制钢弹簧浮置板道床顶升精度探析
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作者 赵磊 《混凝土世界》 2024年第4期80-83,共4页
城市轨道交通线路在经过密集居民区、医院、精密实验室、剧院等特殊路段时,车辆运行发出的振动和噪音会严重影响周边环境和居民生活,因此在轨道工程轨道施工中,常采用钢弹簧浮置板道床,其减振、降噪效果最为显著,而在钢弹簧浮置板道床... 城市轨道交通线路在经过密集居民区、医院、精密实验室、剧院等特殊路段时,车辆运行发出的振动和噪音会严重影响周边环境和居民生活,因此在轨道工程轨道施工中,常采用钢弹簧浮置板道床,其减振、降噪效果最为显著,而在钢弹簧浮置板道床顶升施工中,浮置板顶升后的精度一直是控制难点。本文以苏州市轨道交通6号线预制钢弹簧浮置板道床为例,探讨了城市轨道交通预制钢弹簧浮置板道床曲线段顶升后的精度,结合实践,分析影响顶升后精度的主要原因,给出解决对策,规避施工难点,有效提高施工精度,总结施工经验并为后续同类型施工提供参考。 展开更多
关键词 城市轨道交通 顶升后精度 数据分析 预制钢弹簧浮置板道床 曲线地段
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流化床化学气相沉积法制备CNT/Fe-Ni/TiO_2及其光催化性能研究 被引量:12
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作者 马磊 陈爱平 +2 位作者 陆金东 何洪波 李春忠 《无机材料学报》 SCIE EI CAS CSCD 北大核心 2012年第1期33-37,共5页
以Fe-Ni/TiO2为催化剂,采用流化床化学气相沉积法(FBCVD)在TiO2表面原位生长碳纳米管(CNT),得到CNT/Fe-Ni/TiO2复合光催化剂.通过SEM、XRD、UV-Vis等方法表征其结构和性能,以亚甲基蓝溶液降解为模型考察其光催化性能.结果表明:Fe-Ni/TiO... 以Fe-Ni/TiO2为催化剂,采用流化床化学气相沉积法(FBCVD)在TiO2表面原位生长碳纳米管(CNT),得到CNT/Fe-Ni/TiO2复合光催化剂.通过SEM、XRD、UV-Vis等方法表征其结构和性能,以亚甲基蓝溶液降解为模型考察其光催化性能.结果表明:Fe-Ni/TiO2催化剂在FBCVD过程中,镍主要起到了CNT生长催化活性位的作用;在生长CNT后的复合光催化剂中,比例较低的Fe3+主要作为电子俘获剂,抑制TiO2光生电子空穴的复合;Ni和CNT共同起到将电子迅速地从TiO2中导出,从而降低光生电子空穴复合几率的作用.三者的协同作用显著改善了TiO2的光催化性能.其中Fe和Ni掺杂量分别为0.25mol%和4.75mol%样品的光催化活性较高,生长CNT后得到的复合光催化剂对亚甲基蓝的降解效率较纯TiO2提高约70%. 展开更多
关键词 过渡金属 TIO2 光催化 流化床 CNT
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循环流化床转折区磨损实验研究 被引量:7
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作者 马增益 严建华 +4 位作者 相纪宏 潘国清 王飞 倪明江 岑可法 《中国电机工程学报》 EI CSCD 北大核心 1998年第1期57-59,72,共4页
本文应用磁控溅射工艺开发了镀膜式磨损测量元件,用来对循环流化床内存在的转折区磨损问题进行了实验研究。根据得到的磨损量增长曲线,循环流化床内受热面的磨损基本上以由沿壁面下滑的颗粒团引起的冲刷磨损为主;循环床内转折区的存... 本文应用磁控溅射工艺开发了镀膜式磨损测量元件,用来对循环流化床内存在的转折区磨损问题进行了实验研究。根据得到的磨损量增长曲线,循环流化床内受热面的磨损基本上以由沿壁面下滑的颗粒团引起的冲刷磨损为主;循环床内转折区的存在由于改变了边壁区下滑颗粒团的流向而引起颗粒团的反向作用力,其磨损速率大幅度上升。本文对不同运行风速、床料粒径、转折角角度的影响进行了对比研究。 展开更多
关键词 循环流化床 转折区 磨损 燃煤技术 锅炉 发电厂
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湍动流化床的流型与流型过渡 被引量:9
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作者 阳永荣 戎顺熙 +1 位作者 陈甘棠 陈伯川 《化学反应工程与工艺》 CAS CSCD 北大核心 1990年第2期8-16,共9页
分别在直径为114mm 和244mm 的流化床中,采用压力探头和光导纤维探头考察了湍动流态化的上、下限及实验判别准则。发现床内局部点处的床空隙率随气速的变化符合于修正的 Richardson-Zaki 关系,并以此可以揭示出局部区域进入湍动流态化... 分别在直径为114mm 和244mm 的流化床中,采用压力探头和光导纤维探头考察了湍动流态化的上、下限及实验判别准则。发现床内局部点处的床空隙率随气速的变化符合于修正的 Richardson-Zaki 关系,并以此可以揭示出局部区域进入湍动流态化的流型过渡(上限)。压力脉动法的测量结果(U_c)还表明:此时,床内湍动流态化区域实际上已经占有相当的份额。另一方面,分析床内压力及床密度的脉动信号随气速的变化,可以判定脱离湍动流态化时的流型转变(下限)。本文还应用 Kolmogoroff 的湍流理论定性地分析了湍动流态化的湍流结构。 展开更多
关键词 湍动流化床 流化床 流型 过渡
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过渡区动床明渠流的流速分布 被引量:6
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作者 刘春晶 李丹勋 +1 位作者 曲兆松 王兴奎 《水科学进展》 EI CAS CSCD 北大核心 2006年第1期49-54,共6页
利用激光流速仪测量了随水流强度加大松散床面,从定床到具有一定输沙强度的动床流动,试验水流条件均处于过渡区。试验资料分析表明,动床过渡区明渠流的卡门常数小于通常所采用的0.4;水流强度逐渐增大,随着推移质运动量增加,阻力系数有... 利用激光流速仪测量了随水流强度加大松散床面,从定床到具有一定输沙强度的动床流动,试验水流条件均处于过渡区。试验资料分析表明,动床过渡区明渠流的卡门常数小于通常所采用的0.4;水流强度逐渐增大,随着推移质运动量增加,阻力系数有减小再增大的趋势;雷诺应力分布和紊动强度分布规律同光滑明渠流类似。 展开更多
关键词 明渠流 过渡粗糙区 动床 推移质 流速分布
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草坪过渡带优质草坪建植与管理综合技术研究——Ⅰ坪床配方 被引量:21
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作者 周嘉友 汤承 +2 位作者 卢建霖 黄昌禄 李笃见 《草业科学》 CAS CSCD 北大核心 1998年第5期44-48,共5页
根据在草坪过渡带地区草坪草对床土要求较为严格和不同类型草坪草对床土要求不同的特点,选用2种冷季型草和2种暖季型草,在8种坪床配方处理下进行了连续3年的坪床配方筛选及对草坪质量的影响试验研究,测定再生速度、建坪速度和持... 根据在草坪过渡带地区草坪草对床土要求较为严格和不同类型草坪草对床土要求不同的特点,选用2种冷季型草和2种暖季型草,在8种坪床配方处理下进行了连续3年的坪床配方筛选及对草坪质量的影响试验研究,测定再生速度、建坪速度和持续生存能力。结果表明:冷、暖季型草坪草的坪床配方均以40%~60%加沙+复合化肥+有机底肥+泥炭为最好;床土中加入有机底肥和泥炭会明显提高草坪的质量和成坪速度;实际建坪时应根据草种类型和建坪质量要求及经费预算情况选用较适合的坪床配方。 展开更多
关键词 草坪过渡带 坪床配方 草坪建植 草坪
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道砟胶对过渡段道床参数的影响规律研究 被引量:8
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作者 朱永见 亓伟 陈攀 《铁道科学与工程学报》 CAS CSCD 北大核心 2016年第1期34-39,共6页
为研究道砟胶对道床参数的影响规律,选取某新建重载铁路2处隧道地段的有砟一无砟过渡段进行现场测试,结果表明:道砟胶结后道床的整体性迅速增强,但随着列车的振动碾压,胶结道床的受力状态得到进一步调整,故心(道床胶结4个月后的... 为研究道砟胶对道床参数的影响规律,选取某新建重载铁路2处隧道地段的有砟一无砟过渡段进行现场测试,结果表明:道砟胶结后道床的整体性迅速增强,但随着列车的振动碾压,胶结道床的受力状态得到进一步调整,故心(道床胶结4个月后的支承刚度)可以较真实地反映道砟胶对道床刚度的影响;随着K(碎石道床的支承刚度)的提高,K/‰逐渐增大,而后趋于稳定,当K0≥70kN/mm,h(枕下黏结厚度)为210~260mm时,心/K主要与断面黏结形式有关,全断面、部分断面和局部断面黏结时,比值分别为2.8,1.66和1.35;全断面/部分断面和局部断面黏结时,可将道床纵、横向阻力提高到规范要求值的6倍和3倍以上,但考虑到局部断面黏结受枕底黏结区域影响大,在道床阻力不足的地段,应黏结肩砟。 展开更多
关键词 道砟胶 过渡段 道床刚度 道床阻力
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基于小波模极大值的湍动流态化流型转变特性研究 被引量:5
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作者 段锋 黄亚继 +1 位作者 李斌 孙宇 《中国电机工程学报》 EI CSCD 北大核心 2011年第26期71-75,共5页
在提升管直径为0.06 m,高度为5 m的冷态流化床试验装置上,使用基于信号奇异性检测的小波模极大值法,研究鼓泡流态化到湍动流态化的流型转变特性,获得相应的流型转变初始速度。使用压力波动平均振幅法和标准偏差法对压力波动信号进行分析... 在提升管直径为0.06 m,高度为5 m的冷态流化床试验装置上,使用基于信号奇异性检测的小波模极大值法,研究鼓泡流态化到湍动流态化的流型转变特性,获得相应的流型转变初始速度。使用压力波动平均振幅法和标准偏差法对压力波动信号进行分析,得到的转变初始速度相互之间的最大标准偏差为10.8%,说明这3种方法均能正确判断鼓泡流态化到湍动流态化的流型转变初始速度。与后两种方法相比,小波模极大值法有使用数据量少、分析速度快的优点。 展开更多
关键词 流化床 湍动 转变速度 小波模极大 压差波动
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涓流床反应器中流区过渡的气相渗透率表征 被引量:5
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作者 程振民 孔祥明 +2 位作者 曹鑫 兰江安 黄子宾 《化工学报》 EI CAS CSCD 北大核心 2010年第7期1770-1776,共7页
由于Ergun方程可适用于气液间无相互作用的两相流动压降计算,并且由气相单相和气液两相并流下的气相压降比值可计算气相相对渗透率,因此,Ergun方程可用于涓流床中不同流区过渡和气液相互作用程度的表征。为检验这一方法的有效性,实验测... 由于Ergun方程可适用于气液间无相互作用的两相流动压降计算,并且由气相单相和气液两相并流下的气相压降比值可计算气相相对渗透率,因此,Ergun方程可用于涓流床中不同流区过渡和气液相互作用程度的表征。为检验这一方法的有效性,实验测定了空气-水体系在内径140mm有机玻璃塔中不同粒径玻璃珠(1.9、3.6、5.2、9.3mm)组成的床层压降和持液量。由于采用了压力传感器和电容层析成像仪,因此可测定脉冲流状态下的瞬态数据。通过压降的实验值与理论值比较,发现Ergun方程的适用范围有限,在没有进入脉冲流前先已失效,说明此时气液间作用已经相当显著。鉴于此,改用气液两相压降实验值代替理论值进行了气体渗透率的计算,发现不同气液流速和颗粒直径下出现脉冲流时的气体渗透率均低于0.08。 展开更多
关键词 涓流床 电容层析成像 持液量 渗透率 流型过渡
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