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数据中心变压器k-factor工程计算方法简析

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建筑电气 2023年第8期42卷 46-52页

作者：高晓明王谋锐上海建筑设计研究院有限公司上海市200041 城地香江(上海)云计算有限公司上海市200120

由k-factor的定义推导其计算公式,并介绍k-factor工程计算方法——采用分类叠加方法对谐波进行简化计算。结合数据中心工程实例给出计算结果并对其进行分析,提出相关注意点,并在此基础之上提出降低数据中心谐波对变压器影响的措施和建议。

关键词：变压器 k-factor 计算方法谐波电流谐波电流含有率谐波源分类数据中心叠加计算

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有关k-factor变压器的浅析和探讨

中国新技术新产品 2012年第12期 2-3页

作者：樊友明上海电气阿尔斯通(武汉)变压器有限公司湖北武汉430415

在过去几十年中,随着我国电力电子技术的迅速发展,大量可控硅的整流设备,制钢用电弧炉,电网用变压器群,饱和电抗器,敏感电子器件,UPS系统等具有非线性阻抗特性的电气设备投入到基础工业部门。这些设备在电力系统中产生大量的谐波,导致... 详细信息

在过去几十年中,随着我国电力电子技术的迅速发展,大量可控硅的整流设备,制钢用电弧炉,电网用变压器群,饱和电抗器,敏感电子器件,UPS系统等具有非线性阻抗特性的电气设备投入到基础工业部门。这些设备在电力系统中产生大量的谐波,导致系统波形畸变严重,对输配电网络,通信线路,电气设备等造成巨大影响,尤其对配电变压器损害更大。k-factor变压器就是可应用于这些非线性负载(non-liner loads)条件下的变压器。

关键词：谐波 k-factor 变压器分析

k-factors and Hamilton Cycles in Graphs

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Acta Mathematica Sinica,English Series 2007年第2期23卷 309-312页

作者： Zhi Guo WANG Zhen Jiang ZHAO College of Mathematics and Information Sciences He'nan University Kaifeng 475001 China P. O. Box 5122 No. 21 Beijin9 100094 China

We discuss k-factors and Hamiltonian Graphs in graph theory. We prove a general version of the conjecture by R. Haggkvist; as a result, we prove two extended versions of two well-known theorems due to O. Ore and B. Ja... 详细信息

关键词： k-factor 2-connected graph Hamilton cycle

k-factors in Regular Graphs

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Acta Mathematica Sinica,English Series 2008年第7期24卷 1213-1220页

作者： Wai Chee SHIU Gui Zhen LIU Department of Mathematics Hong Kong Baptist University Hong Kong P. R. China School of Mathematics and Systems Science Shandong University Ji'nan P. R. China

Plesnik in 1972 proved that an （m - 1）-edge connected m-regular graph of even order has a 1-factor containing any given edge and has another 1-factor excluding any given m - 1 edges. Alder et al. in 1999 showed that if G is a regular （2n ＋ 1）-edge-connected bipartite graph, then G has a 1-factor containing any given edge and excluding any given matching of size n. In this paper we obtain some sufficient conditions related to the edge-connectivity for an n-regular graph to have a k-factor containing a set of edges and （or） excluding a set of edges, where 1 ≤ k ≤n/2. In particular, we generalize Plesnik＇s result and the results obtained by Liu et al. in 1998, and improve katerinis＇ result obtained 1993. Furthermore, we show that the results in this paper are the best possible.

关键词： regular graph k-factor edge-connectivity

The USLE soil erodibility nomograph revisited

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International Soil and Water Conservation Research 2023年第1期11卷 1-13页

作者： Eva Corral-Pazos-de-Provens ígor Rapp-Arraras Juan M.Domingo-Santos School of Engineering University of HuelvaE-21007 HuelvaSpain

The nomograph by Wischmeier et al.(1971)for calculating the k-factor in the USLE was extremely useful when there was low access to ***,the generalised calculation of this factor requires the development of analytic *** paper presents a detailed analysis of the nomograph and its underlying equation,which is applicable only when the silt plus very find sand fraction does not exceed 70%.We also examined the quality of fit on the nomograph of the adaptations to the equation that have been proposed,as a means of dealing with those areas where the original equation is not *** models are shown to have areas where the fit is deficient or even ***,the family of curves on the nomograph for the various values taken by the organic matter are not coincident with the mathematical function from which they presumably *** study also identifies those areas of the textural triangle in which the soils originally used in developing the USLE are located,with a view to according a lower predictive value to the contrasting areas in which calculations of the k-factor will necessarily be ***,a new equation for calculating the k-factor is presented,which accurately reproduces the different sections of the nomograph,and allows the poorly functioning graph to be dispensed *** paper ends with a link to a tool in R for simplifying the procedure for calculating the k-factor,taking into account varying situations of data availability.

关键词： k-factor RUSLE Soil texture Organic matter Very find sand Soil loss prediction

Wireless Channel Measurements and Modeling of LTE Broadband System for High-Speed Railway Scenarios

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Chinese Journal of Electronics 2018年第5期27卷 1092-1097页

作者： ZHAO Hua LYU Qing LIU Yachuan CHEN Jiaxing ZHANG Shujing Hebei Normal University Career Technical College

In high-speed scenarios, channel model is of vital importance in Long term evolution(LTE) *** extensive measurements on Beijing-Tianjin railway, this paper proposes a distance-dependent channel model. Both large-scale and small-scale channel characteristics are presented in detail. The large-scale path loss is modeled under the hierarchical network structure. Small-scale channel characteristics that include channel impulse response,power delay profile and Doppler spectrum are deduced and analyzed. In particular, a new stage-wise k-factor model is proposed. Combined with the cumulative distribution function of Root-mean squared(RMS) delay spread and the number of paths, they clearly illustrate the distancedependent variances of the channel. Finally, the integrated distance-dependent channel models are proposed to give a comprehensive description of broadband LTE channel in high-speed railway scenario.

关键词： Distance-dependent channel model High-speed railway LTE system k-factor Delay spread

Design of proton beam optics to realize beam distribution transformation in C-ADS HTBT

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Chinese Physics C 2013年第2期37卷 85-91页

作者：王相綦罗焕丽郝浩唐靖宇李为民徐宏亮 National Synchrotron Radiation Lab. University of Science and Technology of China School of Nuclear Science and Technology University of Science and Technology of China Institute of High Energy Physics Chinese Academy of Sciences

The linac to the transmuter beam transport line （LTBT） connecting the end of the linac to the spallation target is a critical sub-system in the accelerator driven system （ADS）. It has the function of transporting the accel-erated high power proton beam to the target with a beam footprint satisfying the special requirements of the minor actinide （MA） transmuter. In this paper, a preliminary conceptual design of the hurling magnet to transmuter beam transport section （HTBT）, as a part of the LTBT, for the China ADS （C-ADS） system is proposed and developed. In this design, a novel hurling magnet with a two dimensional amplitude modulation （AM） of 1 kHz and scanning of more than 10 kHz at 360 in transverse directions is used to realize a 300 mm diameter uniform distribution of beam on target. The preliminary beam optics design of C-ADS HTBT optimized to minimize the beam loss on the vacuum chamber and the radiation damage caused by back-scattering neutrons will be reported.

关键词： C-ADS LTBT HTBT hurling magnet k-factor double-waist

Modelling soil erodibility in mountain rangelands of southern kyrgyzstan

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Pedosphere 2020年第4期30卷 443-456页

作者： Maksim kULIkOV Udo SCHICkHOFF Alexander GRONGROFT Peter BORCHARDT Centrum für Erdsystemforschung und Nachhaltigkeit(CEN) Center for Earth System Research and SustainabilityInstitute of GeographyUniversity of HamburgHamburg D-20146(Germany) Centrum für Erdsystemforschung und Nachhaltigkeit(CEN) Center for Earth System Research and SustainabilityInstitute of Soil ScienceUniversity of HamburgHamburg D-20146(Germany)

Soil erosion in mountain rangelands in kyrgyzstan is an emerging problem due to vegetation loss caused by overgrazing. It is further exacerbated by mountain terrain and high precipitation values in Fergana range in the south of kyrgyzstan. The main objective of this study was to map soil erodibility in the mountainous rangelands of kyrgyzstan. The results of this effort are expected to contribute to the development of soil erodibility modelling approaches for mountainous areas. In this study, we mapped soil erodibility at two sites, both representing grazing rangelands in the mountains of kyrgyzstan and having potentially different levels of grazing pressure. We collected a total of 232 soil samples evenly distributed in geographical space and feature space. Then we analyzed the samples in laboratory for grain size distribution and calculated soil erodibility values from these data using the Revised Universal Soil Loss Equation (RUSLE) k-factor formula. After that, we derived different terrain indices and ratios of frequency bands from ASTER GDEM and LANDSAT images to use as auxiliary data because they are among the main soil forming factors and widely used for prediction of various soil properties. Soil erodibility was significantly correlated with channel network base level (geographically extrapolated altitude of water channels), remotely sensed indices of short-wave infrared spectral bands, exposition, and slope degree. We applied multiple regression analysis to predict soil erodibility from spatially explicit terrain and remotely sensed indices. The final soil erodibility model was developed using the spatially explicit predictors and the regression equation and then improved by adding the residuals. The spatial resolution of the model was 30 m, and the estimated mean adjusted coefficient of determination was 0.47. The two sites indicated different estimated and predicted means of soil erodibility values (0.035 and 0.039) with a 0.05 significance level, which i

关键词： channel network base level k-factor LANDSAT RUSLE soil enhancement ratio soil mapping slope terrain

On (g, f)-Uniform Graphs

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Acta Mathematicae Applicatae Sinica 2005年第1期21卷 67-76页

作者： Gui-zhenLiu YanLiu DepartmentofMathematics ShandongUniversityJinan250100China DepartmentofMathematics SouthernNormalUniversityGuangzhou510631China

A graph G is called a (g, f)-uniform graph if for each edge of G, there is a(g, f)-factor containing it and another (g, f)-factor excluding it. In this paper a necessary andsufficient condition for a graph to be a (g, f)-uniform graph is given and some applications of thiscondition are discussed. In particular, some simple sufficient conditions for a graph to be an [a,b]-uniform graph are obtained for a b.

关键词： (g, f)-factor (g, f)-uniform graph [a, b]-factor k-factor