两类距离图的分式色数和点色数

分式色数和点色数是图的两个重要参数。本文在文献 [1]的基础上给出了两类距离图G(Z ,Dm ,k,k + 1)与G(Z ,Dm ,k ,k + 1,k + 2 )的分式色数和点色数。     

Fault modeling on complex field using least‐square circle fitting for linear analog circuits

A new fault modeling method using least‐square circle fitting (LSCF ) for linear analog circuits is proposed in this paper. In this method, Monte Carlo simulation is used to obtain the output voltage values when the parameter of one faulty component is changed while those of the other components vary within their tolerance limits. All the output response voltage values for every faulty circuit statue are decomposed into real and imaginary parts on a complex field. Then, LSCF method is adopted to match these data, yielding a corresponding circular curve on complex plane, which also can be expressed with a circular function. Its center coordinates and radius are established as the fault features. During measurements, by calculating the distance from one real output to each circular center coordinate and comparing the distance with each circular radius, a faulty component can be diagnosed. The effectiveness of the proposed approach is verified by experiments. The results show that (i) the proposed fault modeling can accurately locate the fault component, and (ii) it can also simply be a fault dictionary. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

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中国石油工程建设公司(CPECC)总承包建设了科威特国家石油公司(KOC)西部油田GC27和GC28集油站及输送管线工程.GC27和GC28站最大年处理量分别达到1 000 ×104t和1 150×104t,是大型现代化集油站,该工程设置有液体段塞捕集器(Slug Catcher).文章介绍了液体段塞流捕集器的设置理由、设计依据、原理与构成以及工艺流程等.     

Electrolysis in a closed electrochemical cell with a small inter-electrode distance. Metal dissolution/deposition in plain electrolytes

The present paper focuses on the specificity of electrolysis during metal dissolution/deposition in a closed electrochemical cell with a small inter-electrode distance. A mathematical model for the electrochemical process in such a cell has been developed. We give an analytical and a numerical solution to the system of mass transfer equations for such a cell, in binary solutions and solutions with supporting electrolyte. The dependence of metal deposition rate on the voltage applied to the cell and on the electrolysis time has been studied by numerical simulation. We also present the results of the experimental study of the rate of silver electrodeposition from an acid solution of AgClO₄ in a cell of size 1 mm × 1 mm. Metal deposition rate in a closed electrochemical cell with a small inter-electrode distance has been demonstrated to be at least three times higher than that at recessed electrodes. The results obtained may be used in the LIGA processes for accelerating the filling of photoresist cavities with metal.     

Classification of weld flaws with imbalanced class data

This paper presents research results of our investigation of the imbalanced data problem in the classification of different types of weld flaws, a multi-class classification problem. The one-against-all scheme is adopted to carry out multi-class classification and three algorithms including minimum distance, nearest neighbors, and fuzzy nearest neighbors are employed as the classifiers. The effectiveness of 22 data preprocessing methods for dealing with imbalanced data is evaluated in terms of eight evaluation criteria to determine whether any method would emerge to dominate the others. The test results indicate that: (1) nearest neighbor classifiers outperform the minimum distance classifier; (2) some data preprocessing methods do not improve any criterion and they vary from one classifier to another; (3) the combination of using the AHC_KM data preprocessing method with the 1-NN classifier is the best because they together produce the best performance in six of eight evaluation criteria; and (4) the most difficult weld flaw type to recognize is crack.     

竖曲线在圆曲线测设中的应用

根据多年的施工经验,总结了一套利用竖曲线计算圆曲线的方法,分析了竖曲线的计算原理,介绍了圆曲线测设的步骤,探讨了该法的适用范围,同时指出该法既方便迅速又不需浪费人工,值得推广使用。     

海底超长距离钢筋砼顶管施工技术与应用

本文介绍了 1 60 0口径、长 1 856m污水排海管道一次连续顶进到位的施工应用技术 ,阐述了顶管施工的主要设备系统的选型、污浆减摩、顶进施工等关键技术。     

我国特大城市土地利用形态与出行总量的距离分布研究

本文在分析城市土地利用形态的基础上，建立了数学模型，模拟城市土地利用形态的不同种类，计算城市出行总量的距离分布和空间分布，总结出反映城市出行总量距离分布的二阶爱尔兰分布模型。利用这个模型．可以较快地对城市出行总量的距离分布进行测算，作为宏观研究交通发展战略的基础。还根据本研究所提出的理论与方法对我国部份特大城市的出行总量的距离分布进行了实践验证，初步验证了本研究结果的可靠性、实用性。     

混凝土构件裂缝宽度计算方法的探讨

混凝土构件裂缝宽度的计算复杂、难度大,国内外学者都投入了大量的精力来研究其计算方法,多年来发展了很多计算理论。主要介绍国内除混凝土规范运用的方法之外的几种典型计算理论。通过对国内研究方法的探讨,可知运用半经验半理论方法计算裂缝宽度尚有一定的不足,仍需进一步改进。