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71.
作为深海采矿系统的重要组成部分,深海集矿机的技术研究和开发一直是许多国家的难题。为了提高深海集矿机在稀软沉积物上的牵引性能,基于水牛蹄的曲面结构特征和特殊几何结构,设计了一款仿水牛蹄蹄型履齿。以该款履齿的结构参数为研究对象,通过对朗肯被动土压力理论的优化,得到了仿水牛蹄蹄型履齿的牵引力解析解,建立了对应的履齿仿生参数对履齿牵引力的影响公式。结合正交试验方法进行了不同形式履齿在沉积物上运动的单、多履齿剪切试验,将仿水牛蹄蹄型履齿与直型履齿、仿水牛蹄轮廓履齿(另一种仿生履齿)进行对比试验,并通过模型车试验验证了该款履齿的可行性。结果表明:3种履齿中,仿水牛蹄蹄型履齿提供的最大牵引力最高。研究可为进一步优化仿水牛蹄蹄型履齿结构参数和提高深海稀软底质机械的牵引性能提供参考依据。 相似文献
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Ultra-high pressure metamorphic rocks in the Dabie-Su-Lu region, China: Their formation and exhumation 总被引:17,自引:0,他引:17
Cong Bolin Wang Qingchen Zhai Mingguo Zhang Ruyuan Zhao Zhongyan Ye Kai 《Island Arc》1994,3(3):135-150
Abstract Based on petrological, structural, geological and geochronological research, the authors summarize the progress of ultra-high pressure (UHP) metamorphic rock study since 1989 by Chinese geoscientists and foreign geoscientists in the Dabie-Su-Lu region. The authors introduce and discuss a two-stage exhumation process for the UHP metamorphic rocks that have various lithologies; eclogite, ultramafics, jadeitic quartzite, gneiss, schist and marble. The metamorphic history of UHP metamorphic rocks is divided into three stages, that is, the pre-eclogite stage, coesite eclogite stage, and retrograde stage. Prior to UHP metamorphism, the ultramafics had a high temperature environment assemblage of mantle and others had blueschist facies assemblages. The granulite facies assemblages, which have recorded a temperature increase event with decompression, have developed locally in the Weihai basaltic rocks. Isotopic ages show a long range from > 700 Ma to 200 Ma. The diversity in protoliths of UHP metamorphic rocks may be related to the variation of isotopic ages older than 400 Ma. The Sm-Nd dating of ~ 220 Ma could reflect the initial exhumation stage after the peak UHP metamorphism in relation to the collision between the Sino-Korean and Yangtze blocks and subsequent events. Petrological and structural evidence imply a two-stage exhumation process. During the initial exhumation, the UHP metamorphic rocks were sheared and squeezed up in a high P/T regime. In the second exhumation stage the UHP metamorphic rocks were uplifted and eventually exposed with middle crustal rocks. 相似文献
74.
基于2-(4′-联苯基)-6-苯基苯并(口恶)唑(PBBO)染料分子发射光谱(λ_(em)~(max)=400nm)和2,3,4,6,7,8-六氢化喹嗪并[9,10,1-f,g]-1-甲基香豆素(CND_(102))的激发光谱(λ_(em)~(max)=388nm)的能级相互匹配,以及表面活性剂胶束的存在是染料分子间能量传递的必备条件,使荧光法测Pb的灵敏度以数量级提高。 相似文献
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76.
Ultrahigh-pressure garnet lherzolite from Chijiadian, Rongcheng County, in the Su-Lu region of eastern China 总被引:3,自引:0,他引:3
Abstract Petrological studies of a serpentinized garnet lherzolite body in Rongcheng of the Su-Lu region of eastern China revealed unusually high pressure. Spinel lherzolite probably in a subducting slab was transformed to garnet lherzolite at mantle depth. During exhumation, they were subsequently subjected to the granulite and then amphibolite overprinting and a phase of serpentinization. The peak P–T conditions of the garnet lherzolite estimated after detailed analysis of the metamorphic texture are 4–5 GPa and 820°C or 5–6 GPa and 780°C, depending on the chosen geothermobarometers. The lower dP/dT of the garnet lherzolite can be interpreted as the results of subduction of an old (say 100 Ma older than the time of collision) and cold, slab underneath the margin of the Sino–Korean craton. 相似文献
77.
In this study, we attempt to put forward a conception of landscape ecological niche, enlightened by international scholars on extending the ecological niche theory from spatial niche to functional niche. That is helpful for comprehensively appraising landscape spatial patterns and ecological functions, also, presents a new method for analyzing landscape fea-tures from multidimensional aspects. The practice process is demonstrated by taking Yan’an region in northwestern China as a case. Firstly, the indices system including spatial attribute and functional attribute is established for assessing landscape ecological niche. Additionally, two-dimensional figures are drawn for comparing the spatio-temporal features of landscape ecological niche in 1987 and 2000 among the 13 administrative counties. The results show that from 1987 to 2000, towards Yan’an region, spatial attribute value of landscape ecological niche changes from 1.000 to 1.178 with an obvious increment, and functional attribute value changes from 0.989 to 1.069 with a little increment, both of which enhance the regional landscape ecological niche. Towards each county, spatial attribute value of landscape eco-logical niche increases to different extent while functional attribute value changes dissimilarly with an increment or a decrement. 相似文献
78.
REN Zhiyuan WANG Lixia 《地理学报(英文版)》2007,17(4):479-486
In this study, we attempt to put forward a conception of landscape ecological niche, enlightened by international scholars on extending the ecological niche theory from spatial niche to functional niche. That is helpful for comprehensively appraising landscape spatial patterns and ecological functions, also, presents a new method for analyzing landscape features from multidimensional aspects. The practice process is demonstrated by taking Yan'an region in northwestern China as a case. Firstly, the indices system including spatial attribute and functional attribute is established for assessing landscape ecological niche. Additionally, two-dimensional figures are drawn for comparing the spatio-temporal features of landscape ecological niche in 1987 and 2000 among the 13 administrative counties. The results show that from 1987 to 2000, towards Yan'an region, spatial attribute value of landscape ecological niche changes from 1.000 to 1.178 with an obvious increment, and functional attribute value changes from 0.989 to 1.069 with a little increment, both of which enhance the regional landscape ecological niche. Towards each county, spatial attribute value of landscape ecological niche increases to different extent while functional attribute value changes dissimilarly with an increment or a decrement. 相似文献
79.
地震导致的砂土液化具有很大的随机性。据此 ,提出了评价砂土液化危险性的确定性与不确定性两种方法。确定性方法是以液化指数为变量的多因子判别分析方法 ,不确定性方法是概率分析法 ,即用概率密度函数判断砂土液化灾害的期望损失值。 相似文献
80.
简要介绍了近年来一些国家地震灾害造成的经济损失占这些国家国内生产总值的比例;主要介绍了多震地区开展地震断层探测研究的概况以断层活动为基础的地震保险试验的内容及研究进展。 相似文献