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三相-六相混合输电系统分析的和差分量法 被引量:1
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作者 张文生 杨英杰 《电工技术学报》 EI CSCD 北大核心 2004年第2期69-72,共4页
三相-六相混合电力系统已有20多年的运行历史,由于六相输电系统结构相对复杂,为系统分析、计算带来了不同于三相系统中的许多新问题,现有的对这种混合输电系统的计算方法繁琐复杂。在对此进行深入研究和探讨的基础上,提出了一种将六相... 三相-六相混合电力系统已有20多年的运行历史,由于六相输电系统结构相对复杂,为系统分析、计算带来了不同于三相系统中的许多新问题,现有的对这种混合输电系统的计算方法繁琐复杂。在对此进行深入研究和探讨的基础上,提出了一种将六相电压、电流变换为三相电压、电流的计算方法,借助于此方法,可将六相系统简化为三相系统,从而可将三相-六相混合输电系统的分析转化为三相电力系统的分析,还特别研究了六相系统中的线路阻抗,三相-六相变压器的三相等效原理。 展开更多
关键词 六相系统 和分量 分量 变压器
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认识数量关系 深化模型思想——特级教师袁晓萍“一起来解决问题”教学片段赏析
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作者 丁朱芹 《华夏教师》 2024年第4期51-52,79,共3页
本文赏析了特级教师袁晓萍“一起来解决问题”一课,她带领三年级的学生回顾一年级的知识,以手势表示加法模型和减法模型的数学故事代入情境,和学生一起改造题目中的条件再解决问题,总结出“总量=分量+分量”这个数量关系,并利用此数量... 本文赏析了特级教师袁晓萍“一起来解决问题”一课,她带领三年级的学生回顾一年级的知识,以手势表示加法模型和减法模型的数学故事代入情境,和学生一起改造题目中的条件再解决问题,总结出“总量=分量+分量”这个数量关系,并利用此数量关系把复杂的问题变简单,让学生在轻松愉悦的学习氛围中认识数量关系,潜移默化中培养和发展学生的模型思想。 展开更多
关键词 数量关系 模型思想 总量和分量
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基于综合量的相间故障距离保护新方案
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作者 黄庆丰 《淮海工学院学报(自然科学版)》 CAS 2014年第1期34-38,共5页
为得到更简单的距离保护方案,以对称分量法为基础推导出和、差两分量和综合量,并分析其应用于电力系统相间距离保护的理论依据,比较了测量元件分别加入和、差分量和综合量时,距离保护反映电力系统相间短路故障位置正确性问题。金属性相... 为得到更简单的距离保护方案,以对称分量法为基础推导出和、差两分量和综合量,并分析其应用于电力系统相间距离保护的理论依据,比较了测量元件分别加入和、差分量和综合量时,距离保护反映电力系统相间短路故障位置正确性问题。金属性相间故障时,综合量能正确测量保护安装处至故障点间距离,且发生两相接地故障时测量阻抗与过渡电阻无关。用相和、差量实现的测量元件解决了Y,d11变压器d侧两相短路故障时相间测量元件测量阻抗不能正确反映被保护线路与变压器正序阻抗的问题,且原理简单。 展开更多
关键词 和分量 分量 综合量 相间测量元件 两相接地故障
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关于制订教学大纲的几点想法——在全国中小学教材审定委员会闭幕大会上的讲话 被引量:1
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作者 刘佛年 《课程.教材.教法》 1986年第11期10-12,17,共4页
同志们: 国家教委的领导同志让我讲几句话。我不想多占时间,只想简单地谈几点意见。对这次会议的精神我表示拥护,东昌同志的报告中关于编、审分开,将来要编写多种多样的教材,以及今后九年制教学大纲的基本原则、指导方针和它的基本要求... 同志们: 国家教委的领导同志让我讲几句话。我不想多占时间,只想简单地谈几点意见。对这次会议的精神我表示拥护,东昌同志的报告中关于编、审分开,将来要编写多种多样的教材,以及今后九年制教学大纲的基本原则、指导方针和它的基本要求,我觉得很好。目前分两步走的办法也很好,我表示拥护。 我想谈的是,在制定或修改教学大纲和编写教材时,必须做一些调查研究工作。下面我就这个问题谈几点想法。 现在我们要修改教学大纲,已有了一个修订稿。这个修订稿是人民教育出版社的同志在国内进行了许多调查研究工作的基础上搞出来的。现行各科教学大纲之所以要修改,这是因为教学计划改变了,教学大纲必须进行修改;另外,我们发现有些教材不太适合实际情况,也就是说,在难易程度和分量等方面,有些教材不是那么恰当,这样下去,对提高广大学校的教学质量是不利的。这是经过调查得出来的结论。我们今天就是根据这个结论来修订大纲。目前主要是对现行大纲进行修订,明年,我们要制定新的教学大纲。目前是小改,将来要大改。我认为,无论是修订。 展开更多
关键词 教学大纲 教学质量 中小学教材 几点想法 修订大纲 基本要求 调查研究工作 现行大纲 九年制 和分量
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基于改进单周矢量控制的SAPF控制方法研究
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作者 程启明 张宇 +2 位作者 谭冯忍 高杰 余德清 《太阳能学报》 EI CAS CSCD 北大核心 2019年第10期2824-2832,共9页
传统的并联型有源滤波器(SAPF)控制均包含检测环节,而单周控制则可省去该环节。但传统的单周控制仅适用于三相对称系统,因此该文引入"零和分量"概念,使其还能实现非平衡状态下的控制。另外在仅采用单周控制时的各开关都工作... 传统的并联型有源滤波器(SAPF)控制均包含检测环节,而单周控制则可省去该环节。但传统的单周控制仅适用于三相对称系统,因此该文引入"零和分量"概念,使其还能实现非平衡状态下的控制。另外在仅采用单周控制时的各开关都工作在高频状态(损耗大),为此引入矢量运算。此外,SAPF直流侧电压常采用PI控制,但效果并不理想,该文采用粒子群算法来优化PI的控制参数,以改善控制性能。仿真和实验结果表明在理想/非理想电源下该文所提方法均能在单个开关周期内消除误差,并维持直流侧电压的稳定。 展开更多
关键词 并联型有源滤波器 单周控制 矢量运算 非平衡电压 和分量
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谈现场直播的基调把握
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作者 林文花 《浙江传媒学院学报》 2004年第4期78-78,共1页
关键词 现场直播 播音员 主持人 现场解说 感情色彩 文字语言 和分量 心理调节能力 理解能力 理论素养
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珠落玉盘,气动韵生——播音语气运用初探
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作者 尚亚娟 《新媒体研究》 2016年第3期93-94,共2页
播音员在面对不同稿件进行播音时必须正确运用语气才能将不同稿件的意思表达准确无误。文章从语气的感情色彩和分量、声音形式两个要点和语气再创作方面进行分析,使播音员能更准确的把握播音技巧。
关键词 语气 感情色彩和分量 声音形式 语气再创作
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Effects of Different Yellowing Conditions on Neutral Aroma Components and Smoking Quality of Flue-cured Upper Leaves
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作者 张真美 赵铭钦 +5 位作者 王一丁 梅雅楠 高净净 李燕 赵东杰 王鹏泽 《Agricultural Science & Technology》 CAS 2017年第3期424-431,共8页
A heated air circulation standard curing barn was used for baking tobacco leaves, and the effects of different yellowing conditions during the baking process on contents of neutral aroma components and smoking quality... A heated air circulation standard curing barn was used for baking tobacco leaves, and the effects of different yellowing conditions during the baking process on contents of neutral aroma components and smoking quality of upper leaves were studied by setting different yellowing time and color-fixing time. The results showed that during the baking process, only by prolonging the yellowing time by 24 h on the basis of control, the content of every kind of neutral aroma components in- creased obviously and the content of solanone increased by nearly 2.20 times. It was unfavorable for the degradation and accumulation of aroma components when only prolonging color-fixing time by 24 h. Prolonging both yellowing time and color- fixing time by 24 h mainly promoted the accumulation of chlorophyll degradation product neophytadiene, which increased by 33.24%, while the degradation and ac- cumulation of some aroma components were inhibited, indicating that only prolonging the yellowing time by 24 h could promote the accumulation of various kinds of neu- tral aroma components and improve the quality of tobacco leaves. The regression models were established of neutral aroma components in the first and second prin- cipal components to total aroma content, which were y=x+0.053 47 (R^2=0.919 7) and y=x+0.147 5 (R^2=0.698 4), respectively, and they were verified to be feasible. 展开更多
关键词 Flue-cured tobacco Yellowing conditions Neutral aroma components Smoking quality PCA and PLS
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罗伯特·德尼罗 无双
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《电影世界》 2010年第10期88-89,3,共3页
德尼罗已年近七十。最近几年,他把主要精力放在一些小成本电影上,特别是轻喜剧类型(——以给它们增加足够的关注和分量),于是,这位曾被誉为"刻画孤独灵魂的大师",其容貌也变得越来越有喜剧感。《弯刀》导演罗德里格兹称他是&q... 德尼罗已年近七十。最近几年,他把主要精力放在一些小成本电影上,特别是轻喜剧类型(——以给它们增加足够的关注和分量),于是,这位曾被誉为"刻画孤独灵魂的大师",其容貌也变得越来越有喜剧感。《弯刀》导演罗德里格兹称他是"所有演员的教父,甚至能靠标志性的皱眉裂嘴微笑得奥斯卡奖。"明年,德尼罗参演的影片将会多达五部,其中有两部半还是喜剧。 展开更多
关键词 轻喜剧 电影 导演 教父 科塞 标志性 影片 精力 传奇 和分量
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《懒园按语》三则
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作者 马河声 《时代人物》 2012年第2期127-127,共1页
一念旧是人对岁月的怀恋和反对,也是一种无奈,更是对亲情、友情、人情的一种咀嚼和反刍,是活着的滋味和分量。阅历浅显的人,无旧可念,生活对于他们一页一页常翻常新,越新越奇,所以,他们是勇往直前义无反顾的,这是活着的气味和胆量,这种... 一念旧是人对岁月的怀恋和反对,也是一种无奈,更是对亲情、友情、人情的一种咀嚼和反刍,是活着的滋味和分量。阅历浅显的人,无旧可念,生活对于他们一页一页常翻常新,越新越奇,所以,他们是勇往直前义无反顾的,这是活着的气味和胆量,这种气味比较冲,胆量比较莽,容易刺鼻,容易出格。 展开更多
关键词 意外 生活 文字 按语 天性 作品 香港 人到中年 和分量 方英文
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请你别出现
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作者 顾秦 《时代风采》 2003年第19期47-47,共1页
童年时音乐课教的儿歌,要么唱高调,要么多少有点空洞的抒情,某天偶然听到一首清新有趣、贴近心灵的歌《童年》,不由分说深深喜欢上了它。青涩的成长期,最爱是《野百合也有春天》那支曲,它让失恋变得那么缠绵而柔美。
关键词 野百合 音乐课 童年 成长期 和分量 空洞 儿歌 偶然 心灵 温度
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健康之花
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作者 李天芳 《医药与保健》 2000年第8期3-3,共1页
关键词 物质的富有 社会变革 生态环境 滋补品 学业负担 自我调整 保健品 努力拼搏 幸福感 和分量
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农金宣传要坚持正确的舆论导向
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《中国农业银行长春管理干部学院学报》 1989年第4期42-42,共1页
全国农行系统宣传工作会议最近在兰州召开。 会议要求农村金融各级宣传部门和宣传干部一定要讲党性,一定要坚持四项基本原则,一定要旗帜鲜明、坚定不移地反对资产阶级自由化。 为了不断加强农村金融宣传工作,会议要求各级农村金融部门... 全国农行系统宣传工作会议最近在兰州召开。 会议要求农村金融各级宣传部门和宣传干部一定要讲党性,一定要坚持四项基本原则,一定要旗帜鲜明、坚定不移地反对资产阶级自由化。 为了不断加强农村金融宣传工作,会议要求各级农村金融部门既要注意发挥自身宣传部门和宣传骨干的作用,不断提高稿件质量和分量,争取农金稿件“进北京、上大报。 展开更多
关键词 正确的舆论 农村金融部门 宣传部门 宣传干部 和分量 反对资产阶级自由化 宣传工作会议 稿件质量 党性 坚持四项基本原则
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Analysis of the Conditional Correlations from Different Genetic Systems Between the Protein Content and the Appearance Quality Traits of Indica Rice 被引量:4
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作者 葛国科 郑希 +2 位作者 吴建国 叶子弘 石春海 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2007年第2期129-137,共9页
A factorial mating design in two environments was conducted using 7 cytoplasmic male sterile lines (A) and 5 restorer lines (R) along with their F1 (A × R) and F2 populations. The unconditional and conditio... A factorial mating design in two environments was conducted using 7 cytoplasmic male sterile lines (A) and 5 restorer lines (R) along with their F1 (A × R) and F2 populations. The unconditional and conditional analyses of genetic models and the corresponding statistic methods, including endospermic, cytoplasmic, and maternal plant genetic systems, were used to analyze the genetic relationships between protein content (PC) and the appearance quality traits of indica rice (Oryza sativa L.). The results from unconditional analysis indicated that PC was significantly correlated with the appearance quality traits of rice, except for the brown rice thickness (BRT). Only the genetic covariance between PC and the brown rice width (BRW) was positively correlative, whereas all the other pairwise traits were negatively correlative. The results from conditional analysis revealed that the weight of brown rice (WBR) or the amylose content (AC) could significantly affect the relationships between PC and the appearance quality traits of indica rice. The conditional analysis showed that WBR might negatively affect the relationships between PC and the brown rice length (BRL), BRW, or BRT through the geuotype x environmental (GE) interaction effects, but positively affected the relationships between PC and the ratio of brown rice length to width (RLW) or the ratio of brown rice length to thickness (RLT). The amylase content could positively affect the relationships between PC and BRL, RLW, RLT through the cytoplasmic effects and maternal additive effects, but negatively affected the relationships between PC and BRW. 展开更多
关键词 indica rice (Oryza sativa L.) COVARIANCE unconditional and conditional analysis methods protein content amylose content appearance quality
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Three-dimensional transformation of magnetization direction and magnetic field component at low latitudes based on vertical relationship 被引量:3
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作者 He Tao Xiong Sheng-Qing Wang Wan-Yin 《Applied Geophysics》 SCIE CSCD 2022年第1期91-106,145,共17页
The transformation of the magnetization direction and the magnetic fi eld component is one of the important methods in magnetic data processing and transformation,which can be conducted in both wavenumber and spatial ... The transformation of the magnetization direction and the magnetic fi eld component is one of the important methods in magnetic data processing and transformation,which can be conducted in both wavenumber and spatial domains.The transformation method in the wavenumber domain has simpler processing expression and higher processing effi ciency than in the spatial domain;however,they are unstable at low latitude.In this paper,the conclusion that the sum is 0 of two vertical magnetic fi eld components(magnetization inclinations are also perpendicular)in 2D is used for the 3D transformation of the magnetization direction and the magnetic field component.In addition,the transformation method at low latitudes based on vertical relationship(VMT)is proposed,which is an iterative algorithm that converts the transformation of the magnetization direction and the magnetic field component at the low latitude into the high latitude.This method restrains the instability of transformation of constant and variable magnetization direction and magnetic fi eld components in low latitudes.The accuracy,stability,and practicality are verifi ed from synthetic models and real data. 展开更多
关键词 the transformation of magnetization direction and magnetic field component wavenumber domain low latitudes vertical relationship iterative algorithm.
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Nonlinear distortion analysis for multisine excitation constrained by power spectral density
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作者 ZHOU Kun-li QU Ji-feng ZHOU Zhen-yu 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2016年第4期350-357,共8页
Nonlinear distortion introduced by an amplifier when subjected to a multisine excitation decreases the measurement accuracy in many metrological and measurement areas. In this paper, we performed qualitative and quant... Nonlinear distortion introduced by an amplifier when subjected to a multisine excitation decreases the measurement accuracy in many metrological and measurement areas. In this paper, we performed qualitative and quantitative analyses of the nonlinear distortion with the multisine excitations constrained by a constant power spectral density. We present the numerical results with respect to different tone spacings,nonlinear orders, harmonic phases and tone distributions. Moreover, three as-pects of contributions are made to further reveal the distortion mechanism. First, we find that the type Ⅱ components for Schr- oeder-phase multisines distribute uniformly but not all in anti-phase to the type I components for the second order nonlinearity. Second,we simulate the variance of the type I and Ⅱ components and their summation to explain the principle of reducing the type Ⅱ distortion by averaging the results obtained using multiple realizations of random-phase multisines. Third, we observe a special distortion distribution mechanism for the Schroeder-phase multisine excitation The results contribute to a better estima-tion and understanding of the nonlinear distortion. 展开更多
关键词 multisine excitation nonlinear distortion power spectral density type I and contributions
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Quantitative comparison of similarity measure and entropy for fuzzy sets
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作者 JUNG Dong-yean CHOI Jung-Wook +1 位作者 PARK Wook-Je LEE Sang-Hyuk 《Journal of Central South University》 SCIE EI CAS 2011年第6期2045-2049,共5页
Comparison and data analysis with the similarity measures and entropy for fuzzy sets were carried out. The distance proportional value between the fuzzy set and the corresponding crisp set was considered by the fuzzy ... Comparison and data analysis with the similarity measures and entropy for fuzzy sets were carried out. The distance proportional value between the fuzzy set and the corresponding crisp set was considered by the fuzzy entropy. The relation between the similarity measure and the entropy for fuzzy set was also analyzed. The fuzzy entropy was reformulated as the dissimilarity measure. Furthermore, crisp set having the minimum uncertainty with respect to the corresponding fuzzy set was also proposed. Finally, derivation of a similarity measure from entropy with the help of total information property was derived. A simple example shows the relation between similarity measure and fuzzy entropy, in which the summation of similarity measure and fuzzy entropy represents a constant value. 展开更多
关键词 similarity measure fuzzy entropy minimum uncertainty quantitative comparison
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Large Deviations for Sums of Heavy-tailed Random Variables
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作者 郭晓燕 孔繁超 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第2期282-289,共8页
This paper is a further investigation of large deviations for sums of random variables Sn=i=1∑n Xi and S(t)=i=1∑N(t)Xi,(t≥0), where {X_n,n≥1) are independent identically distribution and non-negative random... This paper is a further investigation of large deviations for sums of random variables Sn=i=1∑n Xi and S(t)=i=1∑N(t)Xi,(t≥0), where {X_n,n≥1) are independent identically distribution and non-negative random variables, and {N(t),t≥0} is a counting process of non-negative integer-valued random variables, independent of {X_n,n≥1}. In this paper, under the suppose F∈G, which is a bigger heavy-tailed class than C, proved large deviation results for sums of random variables. 展开更多
关键词 large deviation heavy-tailed distribution strongly subexponential distribution lognormal distribution
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Ultra High Energy Cosmic Rays: Spectral Signatures and Observations
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作者 Svetlana Grigorieva 《Journal of Physical Science and Application》 2014年第6期393-397,共5页
The observations of Ultra High Energy Cosmic Rays (UHECR) are renewed, focusing on the energy spectra as measured by HiRes, Telescope Array (TA) and Auger detectors (PAO). It is found that highest energy Auger s... The observations of Ultra High Energy Cosmic Rays (UHECR) are renewed, focusing on the energy spectra as measured by HiRes, Telescope Array (TA) and Auger detectors (PAO). It is found that highest energy Auger steepening does not agree with GZK cutoff, which is most probably explained by the nuclei mass composition detected by Auger. At present the difference in mass composition in Auger and HiRes/TA data remains the main unsolved problem of UHECR origin. 展开更多
关键词 Ultrahigh energy cosmic ray origin CMB radiation GZK cutoff.
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Performance of an Improved One-Way Error Reconciliation Protocol Based on Key Redistribution 被引量:2
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作者 ZHAO Feng LI Jingling 《China Communications》 SCIE CSCD 2014年第6期63-70,共8页
In data post-processing for quantum key distribution, it is essential to have a highly efficient error reconciliation protocol. Based on the key redistribution scheme, we analyze a one-way error reconciliation protoco... In data post-processing for quantum key distribution, it is essential to have a highly efficient error reconciliation protocol. Based on the key redistribution scheme, we analyze a one-way error reconciliation protocol by data simulation. The relationship between the error correction capability and the key generation efficiency of three kinds of Hamming code are demonstrated. The simulation results indicate that when the initial error rates are (0,1.5%], (1.5,4%], and (4,11%], using the Hamming (31,26), (15,11), and (7,4) codes to correct the error, respectively, the key generation rate will be maximized. Based on this, we propose a modified one-way error reconciliation protocol which employs a mixed Hamming code concatenation scheme. The error correction capability and key generation rate are verified through data simulation. Using the parameters of the posterior distribution based on the tested data, a simple method for estimating the bit error rate (BER) with a given confidence interval is estimated. The simulation results show that when the initial bit error rate is 10.00%, after 7 rounds of error correction, the error bits are eliminated completely, and the key generation rate is 10.36%; the BER expectation is 2.96×10^-10, and when the confidence is 95% the corresponding BER upper limit is 2.17×10^-9. By comparison, for the single (7,4) Hamming code error reconciliation scheme at a confidence of 95%,the key generation rate is only 6.09%, while the BER expectation is 5.92x 10"9, with a BER upper limit of 4.34×10^-8. Hence, our improved protocol is much better than the original one. 展开更多
关键词 quantum key distribution error reconciliation data post-processing
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