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目前地质岩芯钻机使用的给进机构型式多样，但主要型式有四种：一是手把式的给进机构（有的已改成手轮式的）；二是制动器自动给进调节器，又称钢绳减压给进机构；三是油缸油压给进式；四是全液压钻机中采用的液压马达直接驱动的封闭链式的给进机构。一、手把式的给进机构。由于各人的体力与精力关系以及操作熟练程度的不同，压力控制是无法均匀的，也就无法满足金刚石钻进工艺要求，不可能做到均匀连续的给进，因此不适应金刚石钻进。 相似文献
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对手把式给进机构和行星式给进机构进行了对比分析，介绍了一种实用的行星式给进机构的参数和特点。 相似文献
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本文综合了国内外水井钻机给进机构型式，详细给出了双向自紧油缸钢丝绳连续给进机构的设计方案。 相似文献
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一般岩心钻机均由回转、给进和升降三大主要机构组成.这三大机构实现了液压传动即为全液压式岩心钻机.目前,地质岩心钻机已经发展到第三代,即所谓全液压式岩心钻机.第一代钻机是手把给进式的;第二代钻机是油压给进式的.纵观地质岩心钻机的演变过程可以看出,地质岩心钻机是随着钻井工艺水平的发展而发展的.钻井工艺的中心问题就是在保证钻孔符合地质设计要求的前提下,最大限度地提高钻进效率.因此,首先要求钻机的回转机构和给进机构能满足一定钻进方法和适应不同岩层钻进的需要,其次还要求这些机构特别是升降机构能最大限度地减少辅助作业时间.近百年来,岩心钻机的结构基本上是围绕着如何完善回转、给进、升降这三大问题在演进着的.四 相似文献
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近年来非开挖钻机飞速发展,水平定向钻进及导向钻进技术在管道建设中占主导地位。着重介绍了目前国内外水平定向钻机的动力头传动和驱动方式,给进机构的给进方式,夹持-拧卸装置、底盘、钻杆装卸装置的机构,并分析了它们的优缺点。 相似文献
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枣庄岩溶塌陷形成机理与致塌模型的研究 总被引：21，自引：2，他引：19
渗压效应是指由于降雨入渗补给岩溶地下水,而对盖层土体产生的综合作用,包括静水增荷效应、垂直渗透效应、吸水软化效应及负压封闭效应。渗压效应致塌机制是多年持续采水区降落漏斗中心部位岩溶塌陷的主要力学机制。本文根据普氏理论及极限平衡理论分别建立了内部塌陷阶段临界土洞的高度表达式及地表塌陷阶段的渗压效应致塌力学模型,并用表达式及模型对枣庄市的岩溶塌陷进行了验证分析与评价,分析结果与实际塌陷情况符合较好,建立的表达式与模型基本上反映了该地区岩溶塌陷的形成机理。 相似文献
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目前,液压动力头岩心钻机大多采用液压缸给进,液压卷扬机提升。近年来,国外多个国家以液压技术见长的公司,研发了无卷扬机液压缸升降式钻机,它与传统钻机设计理念不同,液压缸不单是给进机构也作为提升机构。这种钻机取消了结构复杂而笨重的卷扬机、天车、游动滑车组。液压缸提升系统井架不承受提升载荷,井架尺寸小,轻便;整个设备体积小、质量轻、成本低、技术经济指标先进。它为研发液压动力头钻机提供了一种新机型。介绍了瑞典山特维克浅钻和挪威MH公司RamRig深孔钻机的结构和其他一些国家研发和应用情况。阐述了双液压缸提升和液压缸-钢丝绳倍速机构两种不同系统的工作原理及应用特点。 相似文献
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Katherine E. VanderKooy Chet F. Rakocinski Richard W. Heard 《Estuaries and Coasts》2000,23(5):621-632
We examined ontogenetic, interspecific, and seasonal trophic patterns among sympatric sunfish species, redspotted sunfish,Lepomis miniatus; redear sunfish,Lepomis microlophus; and bluegill,Lepomis macrochirus, in an estuarine bayou. In particular we studied these feeding patterns in relation to relative abundances of prey from different benthic feeding habitats. All three sunfishes showed ontogenetic divergence in their trophic niches, reflecting different ecomorphological specializations. Small fishes depended on zooplankton, whereas larger fishes of all three species shifted their diets to benthic macrofauna. A potential for trophic resource partitioning was reflected by dietary differences among the three sunfish species. One impalied mechanism for resource partitioning was feeding habitat, as redear sunfish frequently used sediment-associated prey, while bluegill showed greater use of water-column-associated prey, and redspotted sunfish often used SAV-associated prey. However, all three sunfishes apparently used each feeding habitat to some degree; and, trophic differences were more clearly based on prey type than on feeding habitat. Redear sunfish, which can crush hard-shelled prey, exhibited the most distinctive diet. An apparent seasonal shift in feeding habitat occurred in autumn/winter, as indicated by increased overlap between diets and SAV. This shift was facilitated by changes in the relative abundances of several common prey types between benthic habitats. The relative abuandance and use of freshwater and estuarine-derived prey also varied seasonally, suggesting a possible trophic benefit of consistent prey availability in the estuarine bayou. 相似文献
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海草床是重要的近海生态系统,生产力极高,可为海洋动物提供良好的栖息地和丰富的有机碳食源;人类活动引起近岸海域的富营养化,可能会改变海草床有机碳源组成和性质,进而影响植食动物和次级消费者的摄食过程及其食物链能量传递效率,从而影响海草床的生物资源产出功能。归纳总结了国内外海草床食物链碳传递过程各方面的研究进展,主要包括:①海草床有机碳源组成及食源贡献;②海草床初级消费者对有机碳源的摄食;③海草床食物网营养级结构及其能量传递;④富营养化对海草床有机碳源组分结构及其成分的影响;⑤海草床食物链能量传递效率对富营养化的响应。在此基础上,提出了未来的研究重点:①联合运用总有机物的稳定同位素比值法、脂肪酸标志法和特定化合物稳定同位素分析方法,加强定量研究海草床各有机碳源的贡献、食物网营养结构图谱、关键碳流途径及其季节性变化规律;探究关键消费者成体和幼体的有机碳源差异,弄清生长阶段的食性转化过程。②结合野外观测、原位围隔实验和室内模拟实验,深入探讨富营养化对海草床有机碳源组成(海草与附生藻类等)及其化学成分(营养质量和次生化合物)的影响,海草等初级生产者成分变化对植食动物和次级消费者摄食过程的影响,以及牧食食物链和碎屑食物链的组成和碳传递效率等的响应机制。 相似文献
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Seagrass beds are highly productive coastal ecosystems, which provide good nursery habitat and abundant Organic Carbon Sources (OCS) as food for marine animals. Human activities have led to widespread eutrophication in coastal areas. Eutrophication may alter the composition and properties of OCS, thereby affecting the feeding process of herbivores and secondary consumer, and energy transfer efficiency in food chain. This may affect the production function of biological resource in seagrass beds. Based on the summary of the foreign and domestic researches, primary achievements were systematically reviewed in this paper in five aspects: the composition of OCS and their contribution, feeding process of herbivore, food web structure and energy transfer efficiency, and their responses to eutrophication. Future researches that should be emphasized were also prospected. With the combined application of stable isotope analysis for bulks and tissues, fatty acid biomarkers and compound-specific stable isotope analysis, the quantitative study of the contribution of OCS, food web structure, key carbon flow pathway and their seasonal change patterns should be enhanced. Meanwhile, the differences of OCS between larval and adult stages of key consumers will need to be further examined to clarify the transformation of their feeding habits. Through field investigation, in-situ mesocosm and laboratory simulation experiments, the effects of nutrient increase on the structure (seagrass and epiphyte, etc.) and chemical composition (nutritional quality and secondary compounds, etc.) of OCS, the response of feeding process of herbivore and secondary consumer to the alteration of chemical compounds in primary producers, and the response mechanism of carbon transfer efficiency of the grazing food chain and detritus food chain need to be further studied. 相似文献
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给进装置是车载钻机的主要执行机构之一,其性能直接影响钻机技术性能的发挥。目前,全液压车载钻机的给进装置大多采用的是两根油缸通过钢丝绳带动动力头运动的伸缩桅杆式结构,结构紧凑,给进行程长。在分析全液压车载钻机给进装置主要工序和负载特性的基础上,ZMK5530TZJ100型车载钻机设计了双泵、双回路控制的液压控制系统,满足快速起下钻及精确钻压控制的正常钻进需求;通过油缸无杆腔贴装防爆阀实现给进装置的可靠悬停功能,避免管路破裂或误操作时钻具自由下落造成的顿钻事故,两个防爆阀可以同步控制油口,并联在一起使两个给进油缸的无杆腔压力相等,保证两油缸同步运行。ZMK5530TZJ100型车载钻机在晋城寺河矿完成了1 675 m的“L”形试验钻孔,验证了给进回路设计的合理性和可靠性。 相似文献
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大瑶山隧道岩溶涌水系统分析 总被引：4，自引：0，他引：4
本文以系统论和控制论为指导分析了大瑶山燧道岩溶涌水系统。通过利用地质结构特征、水化学场和同位素场的综合信息分析,详细阐述了岩溶涌水的补给来源和范围以及水动力的补排关系。建立了较逼真的岩溶涌水水文地质模型和数学模型,并对涌水过程进行了数值模拟分析。最后分析了涌水所造成的地面塌陷机理并给出其整治方案。 相似文献