可靠性下限与可靠寿命下限间的对称原理

本文讨论了可靠性下限与可靠寿命下限间的关系,指出这种关系是对称关系,亦可称对称原理。利用这种对称原理,可由某种失效分布的可靠寿命下限非常方便地导出该分布的可靠性下限,反之亦然。并且对各种常见的失效分布来说明这个对称原理应用的威力。与许多文献相比,其推导简洁,工程物理概念清楚,极易为工程人员掌握。     

陕甘宁盆地中部奥陶系碳酸盐风化壳中的地开石及其与储层的关系

陕甘宁盆地奥陶系碳酸盐古风化壳天然气储集层中存在丰富的高岭石族矿物，经扫描电镜观察、单矿物样的Ｘ射线衍射、红外吸收光谱及差热分析，确认为地开石，而不是高岭石。由于地开石的存在反映酸性的成岩介质，这不利于作为孔隙封堵物的高铁、锰方解石和白云石的沉淀，而有利于碳酸盐矿物的溶解，对埋藏成岩过程中储层孔隙的保存与发育极为有利；同时由于地开石的分子体积小于高岭石，高岭石向地开石的转化会有多余的孔隙空间出现．并形成更多的晶间孔隙，因而地开石通常是好储层的指示矿物。此外．据该地开石形成温度判断，奥陶系碳酸盐储层所经历的最大古地温为１４０～１６０℃。     

维修性评定

对维修时间服从指数、正态、对数正态分布的情况,本文给出了评定维修性、MTTR、最大维修时间、中位维修时间的置信上(下)限方法。     

基于下确界函数的稳定性定号导函数理论与设计

通过建立一种基于下确界函数的被称为定号Ｌｉａｐｕｎｏｖ导函数的设计理论与方法，研究了动态系统稳定性的一类新的判定方法。分析了定号导函数的某些性质，与多项式函数的关系，正定性判别，正定性度量，极坐标方法以及ｖ（ｘ）的正定化算法等基本问题。从而初步形成一个新的、相对系统化的关于稳定性判定的理论框架。     

NEW OBSERVATIONS OF THE LOBOPOD-LIKE WORM FACIVERMIS FROM THE EARLY CAMBRIAN CHENGJIANG LAGERSTTTE

THE EARLY CAMBRIAN CHENGJIANG LAGERST?TTE HAS BEEN CELEBRATED FOR ITS EXCELLENTLY PRESERVED SOFT-BODIED FOSSILS, WHICH ARE SIGNIFICANT FOR UNDER- STANDING THE EVOLUTION OF METAZOANS. ONE OF THE RARE WORM-LIKE FOSSILS, FACIVERMIS YUNNANICUS[1], WHICH HAS5 …     

结合环下根的内部构造及下根构造的模刻划

对于给定的结合环类χ,本文给出了构造结合环A的χ下根的一个方法,并用模的语言刻划了下根的构造过程.     

Types and biotic successions of Ordovician reefs in China

Ordovician reefs are located in the South China,Tarim,and North China blocks,in low-latitude epicontinental marine regions and mostly consist of large-scale carbonate platforms.During the Paleozoic,faunal radiation reef biota diverged and thrived in diverse paleogeographic settings.Algal reefs of the Early Ordovician,Calathium-lithistid sponge-algal reefs of the late Early Ordovician to early Middle Ordovician,and coral-stromatoporoid-algal reefs of the early Late Ordovician,indicate change from Cambrian to Paleozoic biota.Coral-stromatoporoid-algal reefs were the basic communities after 100 Ma.The macroevolution of biotic struc-tures generally shows increased complexity;the evolution of China’s reef biota parallels that worldwide.Important aspects are:(1) The Calathium-algal reefs from the early Tremadocian Nantzinkuan Formation,Zhangjiajie,western Hunan are the pioneer reefs,and the Darriwillian Yijianfang Formation,Bachu are the relic reefs.(2) The bryozoan-dominated reefs of the late Tremadocian Fenhsiang Formation,Middle Yangtze Platform are unique.(3) The early coral-stromatoporoid-algal reefs are highly restricted in China.(4) The algal reefs from the latest Katian on the western margin of the Yangtze Platform,represent an abnormal reef-building environment during the initial stages of Gondwanan glaciations.     

First record of Lower Triassic <Emphasis Type="Italic">Undichna</Emphasis> spp. fish swimming traces from Emei,Sichuan Province,China

We discuss traces from the ichnospecies Undichna unisulca recorded from the Triassic that are reported for the first time in this paper. These fossils are also some of the oldest vertebrate ichnites discovered in China to date. The fish swimming traces (Undichna unisulca) described originate from the Lower Triassic. These traces were found in the Jialingjiang Formation and are located at a gorge ~7.5 km from Emei, Sichuan Province, China. The ichnospecies Undichna unisulca consists of a regular sinusoidal wave. The wavelengths and amplitudes are quite constant between each specimen ranging between 28-32 mm and 9-12 mm, respectively. The fish swimming traces and distribution within the same bed are preserved as hypichnial ridges at the undersurface.     

关于矩阵共轭特征值的若干估计

给出了矩阵共轭特征值的Gerschgorin型估计式,得到了最小下界的某些估计.     

安次地区奥陶系潜山裂缝特征及油气地质意义

针对安次地区奥陶系潜山储层非均质性强、井间生产差异性大等问题，利用岩芯、薄片及测录井等资料，对研究区内裂缝类型、发育程度及有效性进行分析，认为工区内发育构造缝、溶蚀缝和成岩缝3类，其中，构造缝最为发育，以NE走向的高角度缝为主；岩性和断层控制裂缝的发育程度，厚度薄、岩性纯、靠近断层发育的白云岩储层裂缝最为发育；张开度和充填程度反映裂缝有效性，研究区裂缝发育，多数裂缝半填充未填充，裂缝有效性好。多口井钻探证实，裂缝具有重要的油气地质意义，它不仅可以改善储层物性条件，还提供油气运移优势通道，提高单井产能，同时，裂缝的形成时期和发育部位控制油气运聚成藏：新近纪以后形成的裂缝发育程度高、有效性好；油气藏内部的裂缝发育，有利于油气运聚，形成富油气聚集区。