共查询到20条相似文献，搜索用时 31 毫秒
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Wilson DS Teagle DA Alt JC Banerjee NR Umino S Miyashita S Acton GD Anma R Barr SR Belghoul A Carlut J Christie DM Coggon RM Cooper KM Cordier C Crispini L Durand SR Einaudi F Galli L Gao Y Geldmacher J Gilbert LA Hayman NW Herrero-Bervera E Hirano N Holter S Ingle S Jiang S Kalberkamp U Kerneklian M Koepke J Laverne C Vasquez HL Maclennan J Morgan S Neo N Nichols HJ Park SH Reichow MK Sakuyama T Sano T Sandwell R Scheibner B Smith-Duque CE Swift SA Tartarotti P Tikku AA Tominaga M Veloso EA 《Science (New York, N.Y.)》2006,312(5776):1016-1020
Sampling an intact sequence of oceanic crust through lavas, dikes, and gabbros is necessary to advance the understanding of the formation and evolution of crust formed at mid-ocean ridges, but it has been an elusive goal of scientific ocean drilling for decades. Recent drilling in the eastern Pacific Ocean in Hole 1256D reached gabbro within seismic layer 2, 1157 meters into crust formed at a superfast spreading rate. The gabbros are the crystallized melt lenses that formed beneath a mid-ocean ridge. The depth at which gabbro was reached confirms predictions extrapolated from seismic experiments at modern mid-ocean ridges: Melt lenses occur at shallower depths at faster spreading rates. The gabbros intrude metamorphosed sheeted dikes and have compositions similar to the overlying lavas, precluding formation of the cumulate lower oceanic crust from melt lenses so far penetrated by Hole 1256D. 相似文献
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Holden C 《Science (New York, N.Y.)》1985,227(4690):1014
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我国车辆用润滑油品种简化方案 总被引：1，自引：1，他引：0
通过分析我国车辆用内燃机油,齿轮油品种,牌号的现状,对地面车辆用润滑油品种、牌号进行了简化。近期内燃机油应废除低级别油料,简化牌号,将内燃机油品种简化为ＳＤ、ＳＥ、ＣＣ和ＣＤ４个级别;实现汽油机油与柴油,机油通用后,可简化为ＳＣ／ＤＤ和ＳＥ／ＣＤ,对于齿轮油等级可简化为普通用齿轮油和重负荷辅助用齿轮油两种。 相似文献
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介绍了管道穿越方案的优缺点和适用环境,提出了运用模糊层次分析法代替层次分析法来优选管道穿越方案的新方法。指出模糊层次分析法不仅比层次分析法简单,而且还解决了一般层次分析法标度繁琐、判断矩阵一致性难等问题。采用模糊层次分析法对某河流的穿越方案进行了优选,最终优选结果与实际工程采用的施工方案一致。 相似文献
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杀虫剂激发害虫再猖獗的评价方案初探 总被引：2，自引：0，他引：2
提出了“害虫再猖獗指数（ｉｎｄｅｘｏｆｐｏｐｕｌａｔｉｏｎｒｅｓｕｒｇｅｎｃｅ；ＩＰＲ）”来评价化学杀虫剂激发害虫再猖獗的效应，并以１１种杀虫剂处理背飞虱的为例介绍了评判杀虫引起害虫再猖獗程度的方法，实例分析表明：ＩＰＲ是评判杀虫剂激发害虫再猖獗效应的合适指标。 相似文献
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用轴测投影图与球面三角相结合求解空间角度,具有精度高和解题迅速的特点。若再与计算机程序相结合,并用电子计算机运算,不仅精度提高,而且效率倍增。 相似文献
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Flores E 《Science (New York, N.Y.)》1979,204(4399):1279-1282
In response to a request by President José López Portillo, the National Council of Science and Technology (CONACYT) worked out a program of scientific research and development in Mexico in keeping with the economic and social priorities of his administration-food production, energy, public health, and employment. Representatives from public, private, and academic sectors participated in preparing an inventory of needs for the development of human, economic, and physical resources. The program includes 2,489 projects in basic and applied sciences at a cost of $260 million to 1982 and 17,000 scholarships at a cost of $130 million. 相似文献
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培养学生程序设计能力探索与实践 总被引：1，自引：0，他引：1
程序设计教学是培养学生进行程序设计和综合运用知识的能力与技能,提高学生综合素质.本文从传统的程序设计教学中存在的一些问题出发,探索培养适应社会需要的创新型人才,需要从课程计划、教学方法、教学手段、教学环境和考核方式等方面进行改革. 相似文献
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Kerr RA 《Science (New York, N.Y.)》1981,213(4510):851-852