基于MCNP程序的海洋核动力平台堆芯核设计校核计算研究

海洋核动力平台是小型核反应堆与船舶工程技术的有机结合,具有机动性好、一次性装料运行周期长、功率密度大、运行成本低、节能环保等特点。本文采用蒙特卡罗粒子输运程序(MCNP),建立海洋核动力平台反应堆堆芯几何模型,计算该反应堆首循环初始装料冷态、常压下的堆芯反应性和控制棒价值,并与核设计计算结果进行对比。结果表明:MCNP程序适用于海洋核动力平台反应堆堆芯核设计校核计算,并可与核设计值互相验证。     

Eigenvalue translation method for stabilizing an unsymmetric Lanczos reduction process

The Unsymmetric Lanczos Reduction method has been recently developed to reduce the size of a large-scale linear system which is the discretized form of a time-dependent partial differential equation problem with a large physical domain. This has been applied to solve the time-dependent advection–dispersion equation discretized by finite element or finite difference methods. However, the reduced system sometimes suffers time instability because of relocation of the approximate eigenvalues into the left half plane. This paper develops a method for stabilizing the reduced system while preserving the accuracy of the solution. The unstable eigenvalues are translated from the left half complex plane to the right half, leaving eigenvalues in right half plane unchanged. The results of numerical simulations of the synthetic and practical field contaminant transport problems show the efficiency and accuracy of this method. © 1998 John Wiley & Sons, Ltd.     

岩体结构面流变特性研究进展

在综述国内外关于岩体流变特性研究现状的基础上,着重探讨了有关岩体流变试验及流变理论中的若干问题,指出岩体结构面的蠕变特性研究对解决岩石力学实际问题具有很重要的意义,最后提出了岩体流变今后研究发展的方向以及可以引进的研究新手段。     

单层平面钢框架连续倒塌动力效应分析

为研究结构连续倒塌由于初始破坏引起的动力效应,该文采用瞬时加载法,对中柱失效的单层平面钢框架分别采用简化模型和杆单元模型进行动力反应分析。分析结果表明:当结构处于线弹性状态时,动力放大效应仅与构件失效时间和阻尼比有关,动力放大系数最大值为2,且随着构件失效时间和阻尼比的增大而减小;当结构屈服进入塑性状态后,动力放大效应还与需求能力比(DCR)有关,动力放大系数随着DCR的增大而增大,直至结构出现动力发散。     

KDP晶体二倍频晶面纳米压痕实验研究

The nanohardness is from 1.44 to 2.61 GPa,the Vickers hardness is from 127 to 252 Vickers,and elastic modulus is from 52 to 123 GPa by the nanoindentation experiments on the doubler plane of KDP crystal. An indentation size effect is observed on the doubler plane in the test as the nanohardness and elastic modulus decreases with the increase of the maximum load.Slippage is identified as the major mode of plastic deformation, and pop-in events are attributed to the initiation of slippage.And the variation of unloading curve end is the result of stick effects between the indenter and the contact surface.The depth of the elastic deformation,which is between 40 and 75 nm,is responsible for the elastic deformation.The doubler plane of KDP crystal has anisotropy,and the relative anisotropy of nanohardness is 8.2%and the relative anisotropy of elastic modulus is 8.0%.     

如何提高工频有芯感应炉的使用寿命

本文阐述了影响上引法连铸铜杆生产线中工频有芯感应炉使用寿命的各种因素 ,重点探讨了耐火材料的选择、粒度、配比、筑炉方法、烤炉制度、熔沟维护和监测以及熔沟形状和炉子结构等对提高工频有芯感应炉炉龄所起的作用。     

基于配准的红外焦平面阵列条纹非均匀性校正

条纹非均匀性是线扫红外焦平面阵列和非制冷凝视型红外焦平面阵列成像系统中一种特殊的固定图案噪声.分析了其产生的原因,提出了一种基于亮度恒定假设和配准的条纹非均匀性校正算法.根据相邻两帧获得亮度均方误差函数,最后通过最小化全局亮度均方误差函数得到全局最优解作为非均匀性校正的参数.实验结果表明,该算法能够在几帧内达到较好的收...     

气体辅助注射成型CAE模型分析与网格生成技术

基于对三维实体流动模型的分析,研究了3D气体辅助注射成型CAE中面网格生成的过程及其关键技术,指出2．5D广义Hele-Shaw模型分析方法是薄壁件气体辅助注射成型3D实体流动模拟中适用性强,数值收敛性较好,且能满足CAE快速分析的实用技术。从此技术得到的shell和beam单元是进行气体辅助注射成型前处理,并进行CAE准确预测分析的重要手段。     

分连体炉在无氧铜杆生产线上的应用

本文介绍了上引法无氧铜杆生产线中新型分连体炉的结构和特点 ,是代替连体炉的新型炉组 ,具有产品质量好 ,能耗低、炉龄长、投资省的综合优点。     

歼击机近距引导效能评估

介绍了载机近距引导的方法、轨迹（路径）特征及参数变化情况,给出了基于近距引导效能的飞机攻击区、导弹发射区的计算方法,并对一定条件下的近距引导效能进行了分析计算。