oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
中国最古老铀矿床成矿年龄及铅同位素示踪铀成矿省  [PDF]
夏毓亮,韩军
地球学报 , 2008, DOI: 10.3975/cagsb.2008.06.15
Abstract: 中国发现的最古老铀矿床(点)集中分布在华北地台东部的鞍本地区及辽东地区其他铀矿化点、华北地台中部的中条山地区和华北地台西部的龙首山地区.通过多年来对这些地区所积累的47件晶质铀矿U-Pb同位素数据的整理处理,指出中国最古老铀矿床(矿点)尽管其成矿地域、成矿类型、成矿地质背景不同,但成矿年龄基本相同,在(1800±100)Ma左右成矿,铀成矿作用发生在早前寒武纪末吕梁造山期,而矿床可能主要在燕山运动期受到叠加改造.对华北地台东部诸省200多件方铅矿的铅同位素数据进行铅同位素数据处理:利用H-H模式分别计算了这些矿石铅源区的μ值及Th/U值,并统计了各省区μ值及Th/U值的均方差S和变异系数x;利用Pb构造模式获取不同地区铅的物质来源.文中还报道了特高放射性成因矿石铅的存在地域.矿石铅同位素示踪表明,我国辽东地区应该是很好的潜在铀成矿省.
Generating Preview Tables for Entity Graphs  [PDF]
Ning Yan,Abolfazl Asudeh,Chengkai Li
Computer Science , 2014,
Abstract: Users and developers are tapping into big, complex entity graphs for numerous applications. It is challenging to select entity graphs for a particular need, given abundant datasets from many sources and the oftentimes scarce information available for them. We propose methods to automatically produce preview tables for entity graphs, for compact presentation of important entity types and relationships. The preview tables assist users in attaining a quick and rough preview of the data. They can be shown in a limited display space for a user to browse and explore, before she decides to spend time and resources to fetch and investigate the complete dataset. We formulate several optimization problems that look for previews with the highest scores according to intuitive goodness measures, under various constraints on preview size and distance between preview tables. The optimization problem under distance constraint is NP-hard. We design a dynamic-programming algorithm and an Apriori-style algorithm for finding optimal previews. The experiments and user studies on Freebase demonstrated both the scoring measures' accuracy and the discovery algorithms' efficiency
挖井跟管法  [PDF]
地质与勘探 , 1959,
Abstract: 我队某地区为泥土?石层,以跟管法不易开井,往往造成井故。曾用150合金?头?进下大管,稍一提起,井壁就坍下;?用130小?透、150大?扩下大管也未成功。为此,?用了挖井跟管法,取得了好的效果。挖井跟管法如图1示意图所示,是一种在?石层开井下大管的办法。首先按地质设计孔位,挖一长1.5米、?1.5米、深4米小井,井壁以支架支好,防止坍下,如小井?有水,以人力抽水器抽出。挖好井后再?机台枕按装机械。开孔前先把长4.2米
服装跟单工作研究  [PDF]
纺织学报 , 2004,
Abstract: 对服装跟单从其作用、程序和内容以及工作技巧等方面进行了分析研究,提出了服装跟单工作的新理念。
见煤预告装置  [PDF]
郭成兴
地质与勘探 , 1960,
Abstract: 见煤预告装置的原理是利用电流间断的流通,使电铃断续的响或使灯泡闪光,从单位时间内电铃响的次数或灯泡闪光的次数,来判别钻头?取孔内岩石的级别。
Preview Note – scientific television shows solutions for ordinary problems  [cached]
Isabel CF da Cruz
Online Brazilian Journal of Nursing , 2006,
Abstract: Preview Note is a regular television broadcast that is intended to air a finite number of episodes related to research, science, and technology.
Uranium Ore-forming Ages of the Oldest Uranium Deposits in China and the Tracing of Uranium Metallogenic Provinces with Lead Isotopes
中国最古老铀矿床成矿年龄及铅同位素示踪铀成矿省

XIA Yu-liang,HAN Jun,
夏毓亮
,韩军

地球学报 , 2008,
Abstract: 中国发现的最古老铀矿床(点)集中分布在华北地台东部的鞍本地区及辽东地区其他铀矿化点、华北地台中部的中条山地区和华北地台西部的龙首山地区.通过多年来对这些地区所积累的47件晶质铀矿U-Pb同位素数据的整理处理,指出中国最古老铀矿床(矿点)尽管其成矿地域、成矿类型、成矿地质背景不同,但成矿年龄基本相同,在(1800±100)Ma左右成矿,铀成矿作用发生在早前寒武纪末吕梁造山期,而矿床可能主要在燕山运动期受到叠加改造.对华北地台东部诸省200多件方铅矿的铅同位素数据进行铅同位素数据处理:利用H-H模式分别计算了这些矿石铅源区的μ值及Th/U值,并统计了各省区μ值及Th/U值的均方差S和变异系数x;利用Pb构造模式获取不同地区铅的物质来源.文中还报道了特高放射性成因矿石铅的存在地域.矿石铅同位素示踪表明,我国辽东地区应该是很好的潜在铀成矿省.
A sneak preview of proof theory of ordinals  [PDF]
Toshiyasu Arai
Mathematics , 2011,
Abstract: This talk is a sneak preview of the project, 'proof theory for theories of ordinals'. Background, aims, survey and furture works on the project are given. Subsystems of second order arithmetic are embedded in recursively large ordinals and then the latter are analysed. We scarcely touch upon proof theoretical matters.
The Dirac Quantum Automaton: a preview  [PDF]
Giacomo Mauro D'Ariano
Physics , 2012,
Abstract: Quantum Information and the new informational paradigm are entering the domain of quantum field theory and gravity, suggesting the quantum automata framework. The quantum automaton is the minimal-assumption extension to the Planck and ultrarelativistic scales of quantum field theory. It can describe localized states and measurements, which are unmanageable by quantum field theory. The automaton theory is a very promising framework for quantum gravity, since it is quantum ab-initio, with relativistic covariance as emergent and not assumed a priori, it is free from all the problems arising from the continuum, it doesn't suffer violations of causality, and has no divergences. It is the natural scenario to accommodate the quantum holographic principle. Lorentz covariance and all other symmetries are violated in the ultrarelativistic Planckian regime, but are perfectly recovered at the Fermi-scale. In the present report, after briefly reviewing the fundamental principles at the basis of the quantum cellular automata extension of quantum field theory, I will present a preview of recent results on the Fermi scale limit [1] and on the Dirac automaton in two space-dimensions [2]. The automaton in three dimensions is under way.
Preview Control of Trajectory Tracking for Servo System Based on Optimal Preview Control Method  [cached]
Mohammed M. Saleh All-bail,Yuegang Tan,Liang Li
Mechanical Engineering Research , 2012, DOI: 10.5539/mer.v2n1p18
Abstract: This paper researches on trajectory tracking control system through simulation, theory and experiment. It deals with the use of Universal Motion and Automation Controller UMAC based on preview control method to give good trajectory tracking performance of 3-axis servo system. The subject of this paper is to study and design space object trajectory tracking controller based on optimal preview method and then implement it in servo system.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.