A 3D numerical simulation of stress distribution and fracture process in a zirconia-based FPD framework

In this study, a numerical approach to the fracture behavior in a three-unit zirconia-based fixed partial denture (FPD) framework was made under mechanical loading using a newly developed three-dimensional (3D) numerical modeling code. All the materials studied were treated heterogeneously and Weibull distribution law was applied to describe the heterogeneity. The Mohr-Coulomb failure criterion with tensile strength cut-off was utilized to judge whether the material was in an elastic or failed state. For validation, the fracture pattern obtained from the numerical modeling was compared with a laboratory test; they largely correlated with each other. Similar fracture initiation sites were detected both in the numerical simulation and in an earlier fractographic analysis. The numerical simulation applied in this study clearly described the stress distribution and fracture process of zirconia-based FPD frameworks, information that could not be gained from the laboratory tests alone. Thus, the newly developed 3D numerical modeling code seems to be an efficient tool for prediction of the fracture process in ceramic FPD frameworks. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 96B: 376-385, 2011

A MAGNITUDE ORDER ESTIMATION METHOD FOR FORECASTING CONCENTRATION DISTRIBUTION OF INDOOR EXPLOSION GAS

在对室内液化石油气泄漏流动过程进行量级估算分析的基础上,提出了一种预测室内泄漏液化石油气浓度分布的简化方法.并结合一次居民室内液化气爆炸事故,讨论了此方法在实际应用中的简易可行性

An Estimation of the Error and Response Time of Temperature Dynamic Measurement

从理论上给出了关于热传导测温中动态测温响应与误差估计。温度测量敏感元件的温度滞后于外界温度的变化，其滞后时间不超过敏感元件的半个特征时间L2/α,所以温度测量误差不超过βL2 /2α，也就是说，在热传导动态温度测量中，温度测量敏感元件的热响应时间可估为 L2/2α，最大温度测量误差可估为βL2 /2α

A model of explosion induced by friction in the process of loaded projectiles penetrating into concrete targets

基于炸药的热爆炸理论,采用炸药的热点温度(也称为临界起爆温度)作为起爆判据,分析了装药弹体在侵彻混凝土厚靶过程中的炸药安全性问题,建立了炸药摩擦起爆的热传导模型.对模型进行了量纲一化分析,得出量纲一热流率幅值Qm与炸药和弹壳界面量纲一温度峰值T′max的关系,以及可在实际工程中应用的临界量纲一控制参数Qmc,同时得到了反映摩擦产生的热量在炸药与弹壳间分配比例关系的量纲一参数ΚⅠ.结果表明,炸药装药和弹壳接触面间的强摩擦是形成热点、从而导致炸药早炸的一个重要因素

室内泄漏燃气浓度分布的一个量级估算方法

在对室内液化石油气泄漏流动过程进行量级估算分析的基础上,提出了一种预测室内泄漏液化石油气浓度分布的简化方法.并结合一次居民室内液化气爆炸事故,讨论了此方法在实际应用中的简易可行性

低渗透油田“层内爆炸”增产技术研究进展

"层内爆炸"增产技术是用于低渗透油田开发的一项综合型技术。本文报告了中国科学院力学研究所近几年在此项工作中的一些研究进展,并提出了下一步工作的重点

Advances in the technology of explosion in fractures used in low permeability reservoirs

系统介绍了层内爆炸增产技术的技术思路,应用前景以及实现该技术所涉及到的一系列关键性技术问题;详细介绍了近年来针对此项技术所开展的一系列研究工作,报告了取得的一些研究成果,并对今后的主要研究工作做了展

个旧高松锡石硫化物矿床成因:来自锡石LA-ICP-MS U-Pb定年及微量元素的制约

高松Sn-Cu矿位于云南省个旧矿区,是中国重要的锡石硫化物矿床之一,其锡矿石储量约67.4 Mt(~1.3%),铜矿石储量为19 Mt(~1.1%),并伴生少量的钨、铍、铋、铅、锌等。矿区分布的中三叠世个旧组灰岩、灰质白云岩,是锡矿床主要的赋矿层位。区内褶皱断裂发育,对矿体的产出起明显的控制作用。高峰山黑云母花岗岩侵入到个旧组碳酸盐