NAUJOKAS Algis
,
VESA Brent
,
PETISHNOK David
贵金属
详细介绍了制备钯和铂锭状固体标准样品的实验方法。该固体标样可用于测定固体样品的电弧/火花发射光谱、火花烧蚀发射光谱和辉光放电质谱(GD-MS)等仪器分析方法。在标准样品的制备过程中，首先将含有33种待测杂质元素的钯或铂溶液进行沉淀和共沉淀得到“贮备”粉末，然后将粉末与99.999%纯金属钯或铂进行熔炼，从而获得杂质元素含量在(5~10)×10-6的固体标准样品。部分杂质元素在沉淀和共沉淀过程、热处理环节会发生损失，在最终得到的锭中，钯标准样品有25个元素、铂标准样品有26个元素得到定量回收，发生污染的元素主要包括金、硼、铁和硅。
关键词:
标准样品
,
仪器分析
,
痕量杂质
,
污染
Finite Elements in Analysis and Design
In this paper, a fast rigid plastic finite element method (FEM) is developed for online application in strip rolling. Firstly, a refined neural network model is established to generate an initial guess for the start of the Newton-Raphson iteration. Secondly, the Hessian matrix is divided into sub-domains for parallel computing. Thirdly, the Brent's method is adopted to speed up the line search for the relaxation factor. Fourthly, the energy functional is partitioned according to the numbering of elements for parallel computing. Fifthly, an energy method with high numerical stability is proposed for predicting the rolling force. Finally, the numerical examples for the strip rolling show that the fast rigid-plastic FEM can meet the requirements both on the computational time and the accuracy. (C) 2010 Elsevier B.V. All rights reserved.
关键词:
Fast rigid-plastic FEM;Initial guess;Line search;Parallelization;Strip rolling;neural-network;diagonal matrix;simulation;force;prediction;model;mill;fem
