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Sufficient Conditions for Shift-Invariant Systems to be Frames in L^2(R^n)

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Acta Mathematica Sinica,English Series 2013年第8期29卷 1629-1636页

作者： Deng Feng LI tao qian Institute of Applied Mathematics College of Mathematics and Information SciencesHe'nan University Department of Mathematics Faculty of Science and TechnologyUniversity of Macao

The main purpose of this paper is to establish some new sufficient conditions under which shift-invariant systems become frames in L2（Rn）. As applications, we obtain new results for Gabor frames.

关键词： Shift-invariant system frame sufficient condition

Mathematical theory of signal analysis vs. complex analysis method of harmonic analysis

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Applied Mathematics(A Journal of Chinese Universities) 2013年第4期28卷 505-530页

作者： qian tao ZHANG Li-ming Department of Mathematics University of Macao Macao Department of Computer and Information Science University of Macao Macao

We present recent work of harmonic and signal analysis based on the complex Hardy space approach.

关键词： Mobius transform Blaschke form mono-component Hardy space adaptive Fourier decomposi-tion rational approximation rational orthogonal system time-frequency distribution digital signal processing,uncertainty principle higher dimensional signal analysis in several complex variables and the Clifford algebrasetting.

A class of iterative greedy algorithms related to Blaschke product

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Science China Mathematics 2021年第12期64卷 2703-2718页

作者： tao qian Lihui Tan Jiecheng Chen Macao Institute of Systems Engineering Macao University of Science and TechnologyMacaoChina School of Applied Mathematics Guangdong University of TechnologyGuangzhou 510006China Department of Mathematics Zhejiang Normal UniversityJinhua 321004China

Mobius transforms,Blaschke products and starlike functions as typical conformal mappings of one complex variable give rise to nonlinear phases with non-negative phase derivatives with the latter being de ned by instantaneous frequencies of signals they *** positive analytic phase derivative has been a widely interested subject among signal analysts(see Gabor(1946)).Research results of the positive analytic frequency and applications appears in the literature since the middle of the 20th *** the positive frequency study a directly related topic is positive frequency decomposition of *** mainly focused methods of such decompositions include the maximal selection method and the Blaschke product unwinding method,and joint use of the mentioned *** this paper,we propose a class of iterative greedy algorithms based on the Blaschke product and adaptive Fourier *** generalizes the Blaschke product unwinding method by subtracting constants other than the averages of the remaining functions,aiming at larger winding numbers,and subtracting n-Blaschke forms of the remaining functions,aiming at generating larger numbers of zero-crossings,to fast reduce energy of the remaining ***,we give a comprehensive and rigorous proof of the converging rate in terms of the zeros of the *** Blaschke product methods are proposed to avoid the in nite phase derivative dilemma,and to avoid the computational diculties.

关键词： complex Hardy space Mobius transform Blaschke product rational orthogonal system Takenaka-Malmquist system mono-component adaptive Fourier decomposition unwinding Blaschke expansion

Approximation of monogenic functions by higher order Szego kernels on the unit ball and half space

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Science China Mathematics 2014年第9期57卷 1785-1797页

作者： WANG JinXun qian tao Department of Mathematics University of Macao

We study the adaptive decomposition of functions in the monogenic Hardy spaces H2by higher order Szeg kernels under the framework of Clifford algebra and Clifford analysis,in the context of unit ball and half *** is... 详细信息

关键词： monogenic Hardy space Szego kernel adaptive decomposition dictionary matching pursuit

Adsorption of arsenate on lanthanum-impregnated activated alumina:In situ ATR-FTIR and two-dimensional correlation analysis study

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Chinese Chemical Letters 2015年第2期26卷 200-204页

作者： qian-tao Shi Wei Yan State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of Sciences

Lanthanum modified materials have been widely used for the removal of hazardous *** this study,in situ ATR-FTIR and two-dimensional correlation analysis were employed to investigate the adsorption mechanism of arsenate（As（V）） on lanthanum-impregnated activated alumina（LAA）.Our results showed that electrostatic interaction attracted As（V） anions to the LAA surface,and then As（V） could form monodentate configuration on the LAA surface at pH *** result of 2D-COS showed that two coexistent adsorbed As（V） species,H2AsO4^- and HAsO4^2-,were adsorbed on the LAA surface without specific sequence at different pH conditions,indicating a negligible role of the incorporated protons of As（V） on the adsorption affinity to LAA *** results of this study reveal insights into LAA surface complexes on the molecular scale and provide theoretical support to new metal oxides design for efficient arsenic removal.

关键词： Arsenic Adsorption Lanthanum-impregnated activated alumina Two-dimensional(2D) correlation

Equivariant Lagrangian Minimal S^3 in CP^3

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Acta Mathematica Sinica,English Series 2006年第4期22卷 1215-1220页

作者： Zhen Qi LI Yong qian tao Department of Mathematics Nanchang University Nanchang 330047 P. R. China

The equivariant Lagrangian minimal immersion of Sa into *** is studied. The complete classification and analytic expression for such kinds of immersions are given.

关键词： complex projective space equivariant lagrangian minimal submanifold

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中空纤维膜换热器传热传质性能的实验研究

低温物理学报 2024年第1期46卷 57-64页

作者：赵飞宇陈华钱涛天津市制冷重点实验室天津商业大学机械工程学院

中空纤维膜换热器可同时实现传质传热，该换热器可应用于吸收式制冷系统以改善制冷性能.为探究该膜换热器在溴化锂吸收式制冷系统的运行工况下的传热传质特性，搭建中空纤维膜换热器性能测试实验台，采用控制变量法探究在热侧不同入口... 详细信息

中空纤维膜换热器可同时实现传质传热，该换热器可应用于吸收式制冷系统以改善制冷性能.为探究该膜换热器在溴化锂吸收式制冷系统的运行工况下的传热传质特性，搭建中空纤维膜换热器性能测试实验台，采用控制变量法探究在热侧不同入口溶液流速、温度下该换热器的传热量及膜通量变化规律特性.结果表明：在热流体其它参数保持不变的情况下，中空纤维膜换热器热侧溶液的入口流速由3.05 m/s增至3.30 m/s时，换热器总传热量与膜通量均随之加大，增幅分别为16.0%和2.2%;该膜换热器的总传热量在冷侧溶液与热侧溶液入口温差10°C至15°C内，增幅达到18.9%,而膜通量受膜两侧溶液的入口温差变化影响较小，增幅仅3.1%.研究表示：温度的变化对中空纤维膜换热器的传热传质性能影响更为显著，而流速的变化对水分子的运动影响较小.

关键词：膜换热器传热传质传热量膜通量换热性能

Spectra of rational orthonormal systems

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Science China Mathematics 2019年第10期62卷 1961-1976页

作者： Qiuhui Chen Pei Dang tao qian Department of Mathematics College of Mathematics and InformaticsSouth China Agricultural UniversityGuangzhou510642China Faculty of Information Technology Macao University of Science and TechnologyMacaoChina Macao Institute of Systems Engineering Macao University of Science and TechnologyMacaoChina

We use the Weyl correspondence approach to investigate the spectral operators of the Laguerre and the Kautz systems. We show that the basic functions in the Laguerre and the Kautz systems are the eigenvectors of modified Sturm-Liouville operators. The results are further generalized to multiple parameters of one complex variable in both the unit disc and the upper half-plane contexts.

关键词： spectral operator Laguerre and Kautz systems TM system Caley transform Heisenberg group Weyl correspondence

Speech enhancement with a GSC-like structure employing sparse coding

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第12期15卷 1154-1163页

作者： Li-chun YANG Yun-tao qian College of Computer Science and Technology Zhejiang University Intelligent Control Research Institute Zhejiang Wanli University

Speech communication is often influenced by various types of interfering signals. To improve the quality of the desired signal, a generalized sidelobe canceller(GSC), which uses a reference signal to estimate the interfering signal, is attracting attention of researchers. However, the interference suppression of GSC is limited since a little residual desired signal leaks into the reference signal. To overcome this problem, we use sparse coding to suppress the residual desired signal while preserving the reference signal. Sparse coding with the learned dictionary is usually used to reconstruct the desired signal. As the training samples of a desired signal for dictionary learning are not observable in the real environment, the reconstructed desired signal may contain a lot of residual interfering signal. In contrast,the training samples of the interfering signal during the absence of the desired signal for interferer dictionary learning can be achieved through voice activity detection(VAD). Since the reference signal of an interfering signal is coherent to the interferer dictionary, it can be well restructured by sparse coding, while the residual desired signal will be removed. The performance of GSC will be improved since the estimate of the interfering signal with the proposed reference signal is more accurate than ever. Simulation and experiments on a real acoustic environment show that our proposed method is effective in suppressing interfering signals.

关键词： Generalized sidelobe canceller Speech enhancement Voice activity detection Dictionary learning Sparse coding