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平面尺寸链换算分析 被引量:3
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作者 李双成 陈兴媚 《新型工业化》 2019年第8期60-64,69,共6页
平面尺寸链是机械制造中控制零件(装配件)精度的重要工具。是机械从业人员必备的技术方法,其计算方法灵活多变,不同的零部件(装配件)控制精度的尺寸链的换算方法不同,这就要求机加工人员掌握不同的尺寸链换算方法。平面尺寸链在尺寸链... 平面尺寸链是机械制造中控制零件(装配件)精度的重要工具。是机械从业人员必备的技术方法,其计算方法灵活多变,不同的零部件(装配件)控制精度的尺寸链的换算方法不同,这就要求机加工人员掌握不同的尺寸链换算方法。平面尺寸链在尺寸链家族中也算是个难点,且遇到的机率又非常高,因此掌握好它的计算技巧非常关键,本文利用几个实例针对投影法和全微分法两种换算方法对平面尺寸链的建立、封闭环与组成环的判断及求解过程展开重点讨论,并通过两种方法的对比分析总结出三点二者的异同,为初学者和深入探讨更好、更简洁的平面尺寸链换算方法提供必要的理论参考。 展开更多
关键词 平面尺寸链 投影法 全微分法 换算分析
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影响水泵必需汽蚀余量(NPSH_r)换算关系的因素分析 被引量:4
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作者 裴毅 田莉 +1 位作者 石三铭 刘可佳 《水泵技术》 北大核心 2007年第3期13-15,共3页
泵转数变化时,其工作性能随之变化,本文通过水热力学性质、动力相似假设、水泵汽蚀性能测试标准对水泵影响的理论分析,揭示了泵在转速变化时的必需汽蚀余量(NPSH_r)换算关系中存在的问题。
关键词 离心泵 必需汽蚀余量(NPSHr) 影响因素 换算分析
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南水北调东线工程睢宁二站水泵泵型选择 被引量:2
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作者 张前进 孙宇 +2 位作者 杜亮 刘剑 张根生 《水泵技术》 北大核心 2015年第3期41-43,48,共4页
概述南水北调东线工程睢宁二站的水位组合、泵型选择原则要求,根据这些工程特点和参数,通过模型泵选择及换算分析等步骤,最终确定水泵模型。
关键词 南水北调东线工程 睢宁二泵站 泵型选择 换算分析
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Multi-scale Analysis of Chaotic Characteristics in a Gas-Solid Fluidized Bed 被引量:1
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作者 甄玲 王晓萍 +2 位作者 陈伯川 黄海 黄春艳 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2002年第3期358-362,共5页
Deterministic chaos theory offers useful quantitative tools tocharacterize the non-linear dynamic be- havior of a fluidized bed andthe developed complexity theory presents a new approach to evaluatefinite sequences. I... Deterministic chaos theory offers useful quantitative tools tocharacterize the non-linear dynamic be- havior of a fluidized bed andthe developed complexity theory presents a new approach to evaluatefinite sequences. In this paper, the non-linear, hydrodynamicbehavior of the pressure fluctuation signals in a reactor wasdiscussed By chaos parameters and complexity measures. Coherentresults were achieved by our multi-scale analysis, which Furtherexposed the behavior in a gas-solid two-phase system. 展开更多
关键词 gas-solid fluidized bed pressure fluctuation chaotic theory complexitytheory
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RELATIVE PRINCIPLE COMPONENT AND RELATIVE PRINCIPLE COMPONENT ANALYSIS ALGORITHM 被引量:2
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作者 Wen Chenglin Wang Tianzhen Hu Jing 《Journal of Electronics(China)》 2007年第1期108-111,共4页
In this letter,the new concept of Relative Principle Component (RPC) and method of RPC Analysis (RPCA) are put forward. Meanwhile,the concepts such as Relative Transform (RT),Ro-tundity Scatter (RS) and so on are intr... In this letter,the new concept of Relative Principle Component (RPC) and method of RPC Analysis (RPCA) are put forward. Meanwhile,the concepts such as Relative Transform (RT),Ro-tundity Scatter (RS) and so on are introduced. This new method can overcome some disadvantages of the classical Principle Component Analysis (PCA) when data are rotundity scatter. The RPC selected by RPCA are more representative,and their significance of geometry is more notable,so that the application of the new algorithm will be very extensive. The performance and effectiveness are simply demonstrated by the geometrical interpretation proposed. 展开更多
关键词 Relative Principle Component (RPC) Relative Transform (RT) Rotundity Scatter (RS)
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The SVD of the EMG basis on the FFT of the Kaiser window 被引量:3
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作者 吕广明 车仁炜 +1 位作者 唐余勇 盛培军 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2005年第3期275-277,共3页
The EMG signal is a present field of research which is a driving force in sources of rehabilitating robots. The FFT with Kaiser Window was used in this paper to analyze the spectral characteristics of the EMG signal a... The EMG signal is a present field of research which is a driving force in sources of rehabilitating robots. The FFT with Kaiser Window was used in this paper to analyze the spectral characteristics of the EMG signal according to the characteristic of time changing and nonlinearity for the EMG signal and good results have been obtained. The singular value expressing the property of every EMG signal at each channel was taken out. It offered important data for the actual control of rehabilitating robots. 展开更多
关键词 EMG signal spectrum analysis FFT with Kaiser SVD
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Regular Quasi Cyclic Low Density Parity Check Codes with Girth 8 from Elementary Number Theory 被引量:1
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作者 He Guofeng Li Xiangxue +2 位作者 Li Qiang Zhou Zhiheng Zheng Dong 《China Communications》 SCIE CSCD 2012年第4期80-88,共9页
This paper is concerned with (3,n) and (4,n) regular quasi-cyclic Low Density Parity Check (LDPC) code constructions from elementary number theory.Given the column weight,we determine the shift values of the circulant... This paper is concerned with (3,n) and (4,n) regular quasi-cyclic Low Density Parity Check (LDPC) code constructions from elementary number theory.Given the column weight,we determine the shift values of the circulant permutation matrices via arithmetic analysis.The proposed constructions of quasi-cyclic LDPC codes achieve the following main advantages simultaneously:1) our methods are constructive in the sense that we avoid any searching process;2) our methods ensure no four or six cycles in the bipartite graphs corresponding to the LDPC codes;3) our methods are direct constructions of quasi-cyclic LDPC codes which do not use any other quasi-cyclic LDPC codes of small length like component codes or any other algorithms/cyclic codes like building block;4)the computations of the parameters involved are based on elementary number theory,thus very simple and fast.Simulation results show that the constructed regular codes of high rates perform almost 1.25 dB above Shannon limit and have no error floor down to the bit-error rate of 10-6. 展开更多
关键词 quasi-cyclic LDPC code error floor Shannon limit number theory
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Multiparty Quantum Secret Sharing Using Quantum Fourier Transform 被引量:3
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作者 HUANG Da-Zu CHEN Zhi-Gang GUO Ying 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第2期221-226,共6页
A (n, n)-threshold scheme of multiparty quantum secret sharing of classical or quantum message is proposed based on the discrete quantum Fourier transform. In our proposed scheme, the secret message, which is encode... A (n, n)-threshold scheme of multiparty quantum secret sharing of classical or quantum message is proposed based on the discrete quantum Fourier transform. In our proposed scheme, the secret message, which is encoded by using the forward quantum Fourier transform and decoded by using the reverse, is split and shared in such a way that it can be reconstructed among them only if all the participants work in concert. Fhrthermore, we also discuss how this protocol must be carefully designed for correcting errors and checking eavesdropping or a dishonest participant. Security analysis shows that our scheme is secure. Also, this scheme has an advantage that it is completely compatible with quantum computation and easier to realize in the distributed quantum secure computation. 展开更多
关键词 quantum secret sharing quantum Fourier transform quantum error correction code
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Semi-Commutators of Toeplitz Operators on Ap(?) 被引量:1
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作者 于涛 孙善利 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2004年第1期7-12,共6页
In this paper, we investigate the semi-commutators of Toeplitz operators on the weighted Bergman spaces Ap(?), and characterize the bounded harmonic functions u and v on the unit disk for which the semi-commutator of ... In this paper, we investigate the semi-commutators of Toeplitz operators on the weighted Bergman spaces Ap(?), and characterize the bounded harmonic functions u and v on the unit disk for which the semi-commutator of Toeplitz operators Tu and Tv is 0 or compact operator. 展开更多
关键词 weighted Bergman space Toeplitz operator semi-commutator harmonic function.
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Pricing Variance Swaps Under Stochastic Volatility with an Ornstein-Uhlenbeck Process 被引量:2
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作者 JIA Zhaoli BI Xiuchun ZHANG Shuguang 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2015年第6期1412-1425,共14页
Pricing variance swaps under stochastic volatility has been an important subject pursued recently. Various approaches have been proposed, mainly due to the substantially increased trading activities of volatility-rela... Pricing variance swaps under stochastic volatility has been an important subject pursued recently. Various approaches have been proposed, mainly due to the substantially increased trading activities of volatility-related derivatives in the past few years. In this note, the authors develop analytical method for pricing variance swaps under stochastic volatility with an Ornstein-Uhlenbeck(OU) process. By using Fourier transform algorithm, a closed-form solution for pricing variance swaps with stochastic volatility is obtained, and to give a comparison of fair strike value based on the discrete model, continuous model, and the Monte Carlo simulations. 展开更多
关键词 Closed-form solution Ornstein-Uhlenbeck process stochastic volatility variance swaps
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