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NONNULL DISTRIBUTION OF THE LIKELIHOOD RATIO CRITERION FOR TESTING THE EQUALITY OF DIAGONAL BLOCKS WITH BLOCKWISE INDEPENDENCE 被引量:5
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作者 A. K. Gupta C. C. Chao(Bowling Green State University Bowling Green, OH 43403-0221 C. C. ChaoJacksonville State Univesity Jacksonville, AL 36265) 《Acta Mathematica Scientia》 SCIE CSCD 1994年第2期195-203,共9页
In this paper, the nonnull moments and the distributions of the likelihood ratio criterion for testing the equality of diagonal blocks with blockwise independence under certain alternatives have derived.
关键词 ratio BLOCKWISE CRITERION DIAGONAL DISTRIBUTION equality FOR INDEPENDENCE LIKELIHOOD NONNULL
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ON TESTING THE EQUALITY OF K MULTIPLE AND PARTIAL CORRELATION COEFFICIENTS
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作者 A. K. Gupta Bowling Green State University, USA D. G. Kabe Sf. Mary’s University, USA 《Acta Mathematica Scientia》 SCIE CSCD 2001年第2期221-223,共3页
Coutsourides (1980) derives an ad hoc nuisance parameter removal test for testing the equality of two multiple correlation coefficients of two independent p variate normal populations, under the assumption that a samp... Coutsourides (1980) derives an ad hoc nuisance parameter removal test for testing the equality of two multiple correlation coefficients of two independent p variate normal populations, under the assumption that a sample of size n is available from each population. He also extends his ad hoc nuisance parameter removal test to the testing of the equality of two multiple correlation matrices. This paper presents likelihood ratio tests for testing the equality of k multiple correlation coefficients, and also k partial correlation coefficients. 展开更多
关键词 Normal populations multiple correlation coefficients equality testing like-lihood ratio test MOMENTS
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循环小数化为分数教学中等比数列的应用
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作者 旷雨阳 王太荣 李兴华 《安顺学院学报》 2024年第1期111-114,共4页
纯循环小数与混循环小数是初等数论中常讲解的内容,但怎样把此两类小数化为分数却没有讲解,通过利用中学的等比数列把纯循环小数和混循环小数化为分数,并给出了纯循环小数和混循环小数化为分数的计算公式。为中小学数学教师教学中,把循... 纯循环小数与混循环小数是初等数论中常讲解的内容,但怎样把此两类小数化为分数却没有讲解,通过利用中学的等比数列把纯循环小数和混循环小数化为分数,并给出了纯循环小数和混循环小数化为分数的计算公式。为中小学数学教师教学中,把循环小数化为分数提供了一个有力的计算公式。 展开更多
关键词 初等数论 等比数列 循环小数 计算公式
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基于TOPSIS法与秩和比法的我国基本医疗服务均等化现状研究 被引量:14
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作者 刘浩然 汤少梁 《中国全科医学》 CAS CSCD 北大核心 2016年第25期3078-3081,共4页
目的评价我国基本医疗服务均等化现状,为卫生行政部门制定优化政策提供理论依据。方法采用分层随机抽样法选取我国东部的山东、江苏、广东,中部的安徽、湖北、湖南,西部的重庆、甘肃、四川9个样本省市,采用TOPSIS法与秩和比(RSR)法评价... 目的评价我国基本医疗服务均等化现状,为卫生行政部门制定优化政策提供理论依据。方法采用分层随机抽样法选取我国东部的山东、江苏、广东,中部的安徽、湖北、湖南,西部的重庆、甘肃、四川9个样本省市,采用TOPSIS法与秩和比(RSR)法评价其基本医疗服务均等化现状。数据来源于2011—2014年的《中国统计年鉴》《中国卫生统计年鉴》及《第五次卫生服务调查》,从中提取2010—2013年基本医疗服务的相关数据。采用世界卫生组织(WHO)提出的全民健康覆盖(UHC)测度维度(包括经济可负担、服务可提供、服务可获得、体系有效性)来评价基本医疗服务均等化现状。结果 TOPSIS法评价结果显示,基本医疗服务均等化排名后3位的省市分别为中部的安徽和西部的重庆、甘肃,而同为西部的四川排名第2;RSR法评价结果显示,排名后3位的省市分别为东部的江苏和西部的重庆、甘肃,而同为西部的四川排名第2。结论国家基本医疗服务均等化在东、中、西部区域间及区域内部均存在差异,其中东、中部优于西部,且西部内部差异最大。 展开更多
关键词 基本医疗服务 均等化 toPSIS法 秩和比法
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汽车变速器变速比的优化设计及实例分析
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作者 张胜男 《机械管理开发》 2024年第8期127-128,132,共3页
汽车变速器是汽车的重要部件之一,其结构简单、操作方便,对于汽车性能有重要的影响。但是其变速比的设计一般使用经验公式或者等比级数分配法,有较大局限性,因此通过对汽车变速器的功能与问题进行分析,在传统分配方式的基础上提出了以... 汽车变速器是汽车的重要部件之一,其结构简单、操作方便,对于汽车性能有重要的影响。但是其变速比的设计一般使用经验公式或者等比级数分配法,有较大局限性,因此通过对汽车变速器的功能与问题进行分析,在传统分配方式的基础上提出了以发动机功率为目标,基于档位使用率的变速比分配优化方法,通过实例验证了该方法的可行性,为变速器变速比的研究奠定了理论基础。 展开更多
关键词 汽车变速器 变速比 等比级数分配法 档位使用率 迭代
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空调水管等径分流三通阻力系数随管径、流速的变化规律
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作者 罗亮 《暖通空调》 2024年第11期80-84,共5页
采用数值模拟方法,得到不同流速下DN80空调水管等径分流三通的局部阻力系数,并通过全尺寸实验验证了模拟结果的准确性。模拟了不同管径管道中等径分流三通在不同流速下直流方向和旁通方向的局部阻力系数,以及DN100管道中不同流量比情况... 采用数值模拟方法,得到不同流速下DN80空调水管等径分流三通的局部阻力系数,并通过全尺寸实验验证了模拟结果的准确性。模拟了不同管径管道中等径分流三通在不同流速下直流方向和旁通方向的局部阻力系数,以及DN100管道中不同流量比情况下直流方向和旁通方向的局部阻力系数。结果表明:随着流速的增大,2个方向的局部阻力系数均呈增大趋势;随着流量比的增大,2个方向局部阻力系数均呈现先减小后增大的趋势。 展开更多
关键词 空调 水管 等径分流三通 局部阻力系数 流速 管径 流量比
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具有自均压功能的新型高增益LLC谐振变换器
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作者 沈晔豪 《现代信息科技》 2024年第16期14-19,共6页
LLC谐振变换器具有开关损耗低、运行效率高的优势,但电压增益调节范围受开关频率与变压器匝比限制,无法满足光伏微网系统应用场景的需要。为此,文章提出一种采用变频控制的高增益LLC谐振变换器。该变换器通过改变传统全桥LLC的整流网络... LLC谐振变换器具有开关损耗低、运行效率高的优势,但电压增益调节范围受开关频率与变压器匝比限制,无法满足光伏微网系统应用场景的需要。为此,文章提出一种采用变频控制的高增益LLC谐振变换器。该变换器通过改变传统全桥LLC的整流网络结构,使其具有更高的升压能力,并使高压侧器件电压应力降低为输出电压的一半,更好地适应高电压场合。文章首先详细分析了该变换器工作在欠谐振模式下的工作原理及自均压原理;其次,推导变换器电压增益及器件电压应力;再次,通过变换器的小信号模型设计闭环控制器,实现了电压闭环;最后,通过搭建一台650 W的实验样机,验证理论分析的正确性。 展开更多
关键词 高增益 谐振变换器 低匝比 自均压
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Power Ratio Gain Technique and General Integral Control
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作者 Baishun Liu 《Applied Mathematics》 2015年第4期663-669,共7页
In conjunction with general integral control, and synthesizing Singular perturbation and Equal ratio gain techniques, this paper proposes a new control design technique, named Power ratio gain technique, and then by L... In conjunction with general integral control, and synthesizing Singular perturbation and Equal ratio gain techniques, this paper proposes a new control design technique, named Power ratio gain technique, and then by Lyapunov method, theorem to ensure regionally as well as semi-globally asymptotic stability is established in terms of some bounded information. The highlight point is that it not only inherits all the essences of Singular perturbation and Equal ratio gain techniques but also makes up for their shortcomings, and then the conservatism of control input can be improved by compromising the Power ratio coefficients. Theoretical analysis, design example and simulation results show that Power ratio gain technique is a simple, practical and powerful tool to deal with the uncertain nonlinear system. 展开更多
关键词 GENERAL Integral CONTROL Nonlinear CONTROL Robust CONTROL Equal ratio GAIN TECHNIQUE SINGULAR Perturbation TECHNIQUE Power ratio GAIN TECHNIQUE Output Regulation
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Equal Ratio Gain Technique and Its Application in Linear General Integral Control
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作者 Baishun Liu 《International Journal of Modern Nonlinear Theory and Application》 2015年第1期21-36,共16页
In conjunction with linear general integral control, this paper proposes a fire-new control design technique, named Equal ratio gain technique, and then develops two kinds of control design methods, that is, Decomposi... In conjunction with linear general integral control, this paper proposes a fire-new control design technique, named Equal ratio gain technique, and then develops two kinds of control design methods, that is, Decomposition and Synthetic methods, for a class of uncertain nonlinear system. By Routh’s stability criterion, we demonstrate that a canonical system matrix can be designed to be always Hurwitz as any row controller gains, or controller and its integrator gains increase with the same ratio. By solving Lyapunov equation, we demonstrate that as any row controller gains, or controller and its integrator gains of a canonical system matrix tend to infinity with the same ratio, if it is always Hurwitz, and then the same row solutions of Lyapunov equation all tend to zero. By Equal ratio gain technique and Lyapunov method, theorems to ensure semi-globally asymptotic stability are established in terms of some bounded information. Moreover, the striking robustness of linear general integral control and PID control is clearly illustrated by Equal ratio gain technique. Theoretical analysis, design example and simulation results showed that Equal ratio gain technique is a powerful tool to solve the control design problem of uncertain nonlinear system. 展开更多
关键词 Equal ratio GAIN TECHNIQUE General INTEGRAL CONTROL Nonlinear CONTROL Robust CONTROL OUTPUT Regulation
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Nonlinear General Integral Control Design via Equal Ratio Gain Technique
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作者 Baishun Liu 《International Journal of Modern Nonlinear Theory and Application》 2014年第5期256-266,共11页
This paper proposes two kinds of nonlinear general integral controllers, that is, one is generic and another is practical, for a class of uncertain nonlinear system. By extending equal ratio gain technique to a canoni... This paper proposes two kinds of nonlinear general integral controllers, that is, one is generic and another is practical, for a class of uncertain nonlinear system. By extending equal ratio gain technique to a canonical interval system matrix and using Lyapunov method, theorems to ensure regionally as well as semi-globally asymptotic stability are established in terms of some bounded information. Moreover, for the practical nonlinear integral controller, a real time method to evaluate the equal ratio coefficient is proposed such that its value can be chosen moderately. Theoretical analysis and simulation results demonstrated that not only nonlinear general integral control can effectively deal with the uncertain nonlinear system but also equal ratio gain technique is a powerful and practical tool to solve the control design problem of dynamics with the nonlinear and uncertain actions. 展开更多
关键词 General Integral CONTROL NONLINEAR CONTROL Robust CONTROL Generic Controller Equal ratio GAIN TECHNIQUE Output Regulation
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Equal Volumes of Sand and Gravel Concrete Mix Ratios in Cameroon and Its Effect on Concrete Compressive Strength
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作者 Patrick Bame Che Yamb Bell Emmanuel Ndigui Billong 《World Journal of Engineering and Technology》 2022年第3期539-549,共11页
In recent years, the rationalization of concrete mix ratios which batches equal volumes of sand and gravel in building projects has been gaining grounds in the Cameroon construction industry. The main objective of thi... In recent years, the rationalization of concrete mix ratios which batches equal volumes of sand and gravel in building projects has been gaining grounds in the Cameroon construction industry. The main objective of this study is therefore to investigate if the concrete produced with rationalized mix ratio can be adopted as conventional mix ratio in terms of minimum required compression strength of concrete for buildings. Specifically this work compared the conventional mix ratio of 350 kg of cement: 400 liters of sand: 800 liters of gravel for a cubic meter and the rationalized batch of 350 kg of cement: 600 liters of sand: 600 liters of 5/15 gravel, 15/25 gravel and a combination of 5/15 + 15/25 gravel. Average compressive tests’results for both the conventional and the rationalized mix ratios were found to meet the minimum compressive strength of 65% at 7 days, 90% at 14 days and 99% at 28 days for gravel size combination 5/15 + 15/25. Single size gravel of 5/15 and 15/25 did not meet the minimum required compressive strength of 20 N/mm<sup>2</sup> for the rationalized mix ratio at 28 days curing based on the minimum compressive strength required, this study arrives at the conclusion that the equal volumes of sand and gravel mix ratio of 350 kg/m<sup>3</sup> of cement: 600 liters of sand: 600 liters of gravel mix ratio can be adopted as a conventional concrete mix ratio for gravel size 5/15 + 15/25. 展开更多
关键词 Conventional Concrete rationalized Concrete Mix ratio Compressive Strength Equal Volumes of Sand and Gravel
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A Cooperative Diversity Analysis of Two User Mobile Communication System with Maximal Ratio Combining
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作者 Sateeshkrishna Dhuli V. V. Mani 《Communications and Network》 2013年第2期134-139,共6页
Cooperative communication is going to play a vital role in the next generation wireless networks. In this paper we derive the expression for symbol error probability (SEP) of a two-user cooperative diversity system, w... Cooperative communication is going to play a vital role in the next generation wireless networks. In this paper we derive the expression for symbol error probability (SEP) of a two-user cooperative diversity system, where two users cooperate through the decode-and-forward (DF) relaying with binary phase-shift keying (BPSK) modulation in a flat Rayleigh fading environment. We compare the computational results obtained by the SEP expression with the simulation results using maximal-ratio combining (MRC), equal-gain combining (EGC) and selection combining (SC) techniques. Numerical results show the performance of a cooperative diversity system with maximal-ratio combining is giving better results compared to SC and EGC techniques. 展开更多
关键词 Symbol Error Probability (SEP) Maximal-ratio COMBINING (MRC) Equal-Gain COMBINING (EGC) Selection COMBINING (SC) DECODE-AND-FORWARD (DF) RELAYING
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基于3D模型的景观建筑物全景纹理映射仿真 被引量:1
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作者 张秋敏 曹治 《计算机仿真》 北大核心 2023年第9期197-201,共5页
数据噪声和点云数据拼接效果均会影响3D模型的构建效果,为提升模型纹理映射效果,降低平面误差,提出城市景观建筑物全景3D模型纹理映射方法。对点云数据展开预处理,线扫描数据去噪后过滤离散点云数据,通过迭代操作去除噪声点,并采用ICP... 数据噪声和点云数据拼接效果均会影响3D模型的构建效果,为提升模型纹理映射效果,降低平面误差,提出城市景观建筑物全景3D模型纹理映射方法。对点云数据展开预处理,线扫描数据去噪后过滤离散点云数据,通过迭代操作去除噪声点,并采用ICP算法对点云数据展开精准拼接。利用半球面等比约束球面映射算法对模型展开纹理映射操作,通过不断调整倍数大小均匀控制球面纹理映射的覆盖范围,完成城市景观建筑物全景3D模型纹理映射。仿真结果表明,所提方法可以高效完成城市景观建筑物全景3D模型纹理映射,且不会出现模型缺失、扭曲、变形、失真和粗糙问题,说明该方法性能较好。 展开更多
关键词 纹理映射 点云数据 离散点云数据 等比约束球面映射
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线上线下混合+项目驱动的数字图像处理教学改革与实践 被引量:1
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作者 周继宇 廖丽君 吴九九 《安顺学院学报》 2023年第6期132-136,共5页
数字图像处理课程是面向电子信息类专业开设的一门专业选修课。在“新工科”建设背景下,传统的数字图像处理课程教学方法还存在着诸多问题:课程缺乏任务导向,学生学习目标不明确;线上资源孤立存在,难以有效适配线下课堂教学;教师侧重对... 数字图像处理课程是面向电子信息类专业开设的一门专业选修课。在“新工科”建设背景下,传统的数字图像处理课程教学方法还存在着诸多问题:课程缺乏任务导向,学生学习目标不明确;线上资源孤立存在,难以有效适配线下课堂教学;教师侧重对知识点的覆盖,忽视知识点的重构;学生项目训练不足,无法快速衔接产业需求。通过采用项目驱动模式与线上线下混合教学模式相融合的方式,可以有效地解决以上问题,提升学生的工程应用综合能力。 展开更多
关键词 线上线下混合教学 项目驱动 理论教学 实践教学
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Effect of Width-to-Thickness Ratio and Thickness Profile Changing on the Critical Instable Shape During Cold Strip Rolling 被引量:1
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作者 宋蕾 沈明钢 +2 位作者 杨利坡 王军生 陈雪波 《Journal of Shanghai Jiaotong university(Science)》 EI 2016年第4期411-418,共8页
Based on the volume constancy with equal flow-per-second and elastic sheet stability theory, a coupling relationship among lateral thickness difference, width-to-thickness ratio of cold rolling strip steel under ideal... Based on the volume constancy with equal flow-per-second and elastic sheet stability theory, a coupling relationship among lateral thickness difference, width-to-thickness ratio of cold rolling strip steel under ideal and actual working conditions, and shape is concluded according to the comprehensive influence principle of various factors on the critical instable shape analyzed in-depth. Firstly, the influence model under actual working condition is developed by referring to the basic relationship between lateral thickness difference and shape under ideal condition. The test results prove that for thin strips with thickness below 0.3 mm, their lateral thickness differences have significant effect on the shape. After then, the combined influence of lateral thickness difference and width-to-thickness ratio on the critical instable shape is concluded according to the elastic sheet stability model, with the synthetic effect of these three factors analyzed. Test data indicate that for cold rolling strip steel with width-to-thickness ratio above 3 000, the critical instability stress difference decreases significantly. Actual measurements are conducted on the lateral thickness differences of two rolls of typical strip manufactured by a sixhigh cold mill, with the influence law of lateral thickness variation and width-to-thickness ratio comprehensively investigated. It is demonstrated that during the production of ultrathin strip steel with different width-to-thickness ratios, the loading roll shapes should be fine adjusted according to the lateral thickness difference of input strips.Therefore, the variation of lateral thickness difference of output strips can meet the requirement of shape stability,so as to obtain fine shape. 展开更多
关键词 cold rolling strip lateral thickness difference width-to-thickness ratio sec flow rate equal
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基于超级电容器储能系统的均压放电控制策略 被引量:17
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作者 张莉 吴延平 +2 位作者 李琛 王凯 张宁 《电工技术学报》 EI CSCD 北大核心 2014年第4期329-333,共5页
由于超级电容器单体电压比较低,在构建储能系统时通常采用多只超级电容器串并联结构。但是,因超级电容器自身参数存在差异,在放电过程中必然会出现超级电容器单体之间电压不平衡的现象,进而影响储能系统的放电效率和能量利用率,甚至影... 由于超级电容器单体电压比较低,在构建储能系统时通常采用多只超级电容器串并联结构。但是,因超级电容器自身参数存在差异,在放电过程中必然会出现超级电容器单体之间电压不平衡的现象,进而影响储能系统的放电效率和能量利用率,甚至影响超级电容器的使用寿命。针对上述问题,本文提出了一种均压放电控制策略,可以将电压失衡达到最小化,从而实现超级电容器能量的高效利用,并通过理论分析和实验研究进一步验证了该策略的可行性。 展开更多
关键词 超级电容器 电压均衡 效率 能量利用率
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等宽明渠交汇口水流一维数学模型 被引量:21
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作者 茅泽育 罗昇 +1 位作者 赵升伟 张磊 《水利学报》 EI CSCD 北大核心 2004年第8期26-32,共7页
本文采用理论分析及试验手段,对等宽明渠缓流交汇水流进行了研究。对交汇口流动的各种影响因素进行了量纲分析,确定表征流动特性的主要物理量。根据水力学基本理论,建立了交汇口上下游水深比的普遍方程,方程中考虑了动量修正系数、动能... 本文采用理论分析及试验手段,对等宽明渠缓流交汇水流进行了研究。对交汇口流动的各种影响因素进行了量纲分析,确定表征流动特性的主要物理量。根据水力学基本理论,建立了交汇口上下游水深比的普遍方程,方程中考虑了动量修正系数、动能修正系数、支流汇入角等影响因素的影响,并对水深比与交汇角、流量比及水流Fr数之间的变化关系进行了讨论。解析表达式的计算结果与实验结果符合较好。 展开更多
关键词 明渠交汇口 水深比 流量比 等宽渠道 缓流
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多种节流形式的动静压轴承有限元—优化分析 被引量:10
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作者 岑少起 郭红 +1 位作者 张少林 李浩群 《机械科学与技术》 CSCD 北大核心 2002年第2期237-239,共3页
在动静压轴承有限元分析的基础上对其不同的节流形式进行了优化计算 ,建立了有限元—优化迭代的计算模型 ,给出了浅腔相当节流比和相当节流液阻的计算方法 ,编制了计算机程序 。
关键词 节流器 有限元-优化 相当节流比 动静压轴承
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大塑性变形制备细晶材料的研究、开发与展望 被引量:33
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作者 陈勇军 王渠东 +2 位作者 彭建国 翟春泉 丁文江 《材料导报》 EI CAS CSCD 北大核心 2005年第4期77-80,共4页
系统介绍了大塑性变形(SPD)细化晶粒的条件和目的,综述了4种主要的大塑性变形工艺的基本原理、特点和应用,剖析了细晶材料的强度和超塑性特征,展示了大塑性变形制备细晶材料的诱人前景和发展方向。
关键词 大塑性变形 细晶材料 制备 展望 开发 塑性变形工艺 细化晶粒 基本原理 发展方向 性特征
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论等耗量微增率和等网损微增率与最优潮流的关系 被引量:6
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作者 王正风 汤伟 +1 位作者 吴昊 谢大为 《电力自动化设备》 EI CSCD 北大核心 2007年第4期39-41,共3页
等耗量微增率准则和等网损微增率准则是经典的电力系统经济运行准则。等耗量微增率准则是电力系统有功负荷分布的最优准则,等网损微增率准则是电力系统无功电源分布的最优准则,而电力系统最优潮流则是近年来经济的调度运行理论。从理论... 等耗量微增率准则和等网损微增率准则是经典的电力系统经济运行准则。等耗量微增率准则是电力系统有功负荷分布的最优准则,等网损微增率准则是电力系统无功电源分布的最优准则,而电力系统最优潮流则是近年来经济的调度运行理论。从理论上对等耗量微增率和等网损微增率与最优潮流进行了分析和推导,通过对目标函数的比较、约束条件的比较、物理含义的分析以及仿真算例的证明,表明最优潮流包含了等耗量微增率和等网损微增率,是这2个准则在电力系统中的进一步灵活运用。 展开更多
关键词 等耗量微增率 等网损微增率 最优潮流 实时电价
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