同位素中子源活化瞬发分析装置

一、基本原理自六十年代中期以来,中子活化瞬发γ射线元素分析技术(PNAA)得到人们广泛重视。与通常的中子活化分析(NAA)技术相比,它分析的是样品中的主要成分,若用同位素中子源,还可进行实时在线连续测定及现场分析。PNAA技术是用热中子与待测元素发生中子俘获反应,处于激发态的产物核在瞬间     

论坛消息的语义漂移分析

引入多维文档模型来组织论坛消息的描述性特征和语义性特征，并在多维索引的基础上，提出了加窗分析技术。目的在于分析论坛站点中语义漂移现象，进而发现论坛中的完整语义信息单元。     

一个用户接口管理系统

本文介绍了一个用户接口管理系统NUUIMS的设计和实现.重点叙述了该系统基于规范化目标用户接口模型的设计思想,系统组成及描述方法.文章也讨论了使用NUUIMS设计而成的用户接口的特点.     

Feasibility analysis of membrane reactors – discovery of reactive arheotropes

A feasibility analysis methodology adopted from reactive distillation is applied to membrane reactors. A model is formulated to depict the reactive liquid phase composition on the retentate side of a continuous type membrane reactor. The effects of both the chemical reaction kinetics and the membrane mass transfer kinetics on the feasible products are elucidated by means of retentate phase diagrams and bifurcation analysis. The proposed method can be applied to various membrane processes, independent of the specific structure of the membrane. Two quaternary reaction systems are considered to illustrate the methodology. In the first hypothetical system, it is shown how selective membranes can influence the sequence of effective volatilities which in turn affects the feasible products of the system. In the second example of practical importance, i.e. the heterogeneously catalysed synthesis of propyl acetate coupled with permeation through a porous polycarbonate membrane, the dusty gas model is applied to describe the component fluxes through the membrane. For the latter reaction system, the existence of reactive arheotrope is demonstrated. Arheotropes represent mass transfer controlled feasible products of membrane separation process.     

基于Vague集的鱼雷研制阶段年度投资分配模型

鱼雷的研制费用在鱼雷整个寿命周期费用中所占比系不大，但研制阶段决定了鱼雷寿命周期费用的绝大部分，闪此对鱼雷研制费用的研究可供鱼雷武器管理和决策者作经费计划综合平衡时参考。文章基于Vague集，提出了Vague集模糊熵的构造方法，进而提出了运用Vague集模糊熵进行鱼雷研制阶段年度投资强度分配的新模型。实例表明，该方法具有实用价值。     

DESIGN AND IMPLEMENTATION OF STATE OBSERVERS IN REACTIVE DISTILLATION

This study demonstrates that state observers can be developed and applied to infer the composition profiles of reactive distillation columns from noise-contaminated temperature measurements. The design and implementation of a Kalman filter (KF) and a Luenberger observer (LO) are carried out, and their performances are quantitatively assessed. The reliability, accuracy, and robustness of the two designs method are examined and compared quantitatively. The design and implementation of a Luenberger observer are simpler and easier to carry out than those of a Kalman filter. On the other hand, a Kalman filter is found to be more robust to a noisy measurements, erroneous initial estimates, and model uncertainties. A Luenberger observer could be used for composition estimation of reactive distillation when an ideal model of the system can reasonably approximate the real system; otherwise, a Kalman filter is recommended to be applied in more practical situations.     

济钢高炉喷煤数学模型的研究与应用

基于湍流两相流理论建立了高炉喷煤两相流动及传质三维数学模型。采用该模型指导高炉生产 ,高炉利用系数由2 .7t/(m3.d)提高到 3 .0 t/(m3.d)以上 ,焦比由 460 kg/t降到 40 0 kg/t,煤比达到 10 0 kg/t,提高了高炉的各项经济技术指标。     

Estimation for the number of components in a mixture model using stepwise split-and-merge EM algorithm

The main difficulty with EM algorithm for mixture model concerns the number of components, say g. This is the question of model selection, and the EM algorithm itself could not estimate g. On the contrary, the algorithm requires g to be specified before the remaining parameters can be estimated. To solve this problem, a new algorithm, which is called stepwise split-and-merge EM (SSMEM) algorithm, is proposed. The SSMEM algorithm alternately splits and merges components, estimating g and other parameters of components simultaneously. Also, two novel criteria are introduced to efficiently select the components for split or merge. Experimental results on simulated and real data demonstrate the effectivity of the proposed algorithm.