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time-domain Analysis of Underground Station-Layered Soil Interaction Based on High-Order Doubly Asymptotic Transmitting Boundary

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Computer Modeling in Engineering & Sciences 2019年第9期120卷 545-560页

作者： Tingjin Liu Siyuan Zheng Xinwei Tang Yichao Gao State Key Laboratory of Subtropical Building Science South China University of TechnologyGuangzhou510640China South China Institute of Geotechnical Engineering South China University of TechnologyGuangzhou510640China School of Civil Engineering and Transportation South China University of TechnologyGuangzhou510640China College of Civil Engineering Huaqiao UniversityXiamen362021China

Based on the modified scale boundary finite element method and continued fraction solution,a high-order doubly asymptotic transmitting boundary(DATB)is derived and extended to the simulation of vector wave propagation in complex layered *** high-order DATB converges rapidly to the exact solution throughout the entire frequency range and its formulation is local in the time domain,possessing high accuracy and good *** with finite element method,a coupled model is constructed for time-domain analysis of underground station-layered soil *** coupled model is divided into the near and far field by the truncated boundary,of which the near field is modelled by FEM while the far field is modelled by the high-order *** coupled model is implemented in an open source finite element software,OpenSees,in which the DATB is employed as a super *** examples demonstrate that results of the coupled model are stable,accurate and efficient compared with those of the extended mesh model and the viscous-spring boundary ***,it has also shown the fitness for long-time seismic response analysis of underground station-layered soil ***,it is believed that the coupled model could provide a new approach for seismic analysis of underground station-layered soil interaction and could be further developed for engineering.

关键词： time-domain analysis layered soil scaled boundary finite element method transmitting boundary continued fraction

Compressed sensing-based time-domain channel estimator for full-duplex OFDM systems with IQ-imbalances

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Science China(Information Sciences) 2017年第8期60卷 176-188页

作者： Hai YU Feng SHU You YOU Jin WANG Tingting LIU Xiaohu YOU Jinhui LU Jianxin WANG Xiaohua ZHU School of Electronic and Optical Engineering Nanjing University of Science and Technology National Key Laboratory of Electromagnetic Environment China Research Institute of Radiowave Propagation National Mobile Communications Research Laboratory Southeast University College of Computer and Information Sciences Fujian Agriculture and Forestry University

In full-duplex orthogonal frequency-division multiplexing(OFDM) systems with in-phase and quadrature(IQ) imbalances, a time-domain least squares(TD-LS) channel estimator is proposed for estimating both the source-to-destination(intended) and the destination-to-destination(self-interference) channels. To further improve the performance, an adaptive orthogonal matching pursuit(OMP) is proposed and its sparsity is estimated by a threshold method. Finally, the full-duplex interference is removed using serial interference cancellation and sphere decoding is used to complete the maximum likelihood detection. Simulation results demonstrate that in terms of both the mean square error(MSE) and the bit error rate(BER), the proposed adaptive OMP performs better than the TD-LS by exploiting the sparse property of the channel. Additionally,compared to the gradient projection, the proposed adaptive OMP is better in the low and medium signal-to-noise ratio(SNR) regions and marginally worse in the high SNR region.

关键词： full-duplex OFDM IQ imbalance channel estimation time-domain least squares adaptive OMP gradient projection

Investigation of copper sulfate pentahydrate dehydration by terahertz time-domain spectroscopy

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Chinese Physics B 2019年第6期28卷 110-113页

作者： Yuan-Yuan Ma Hao-Chong Huang Si-Bo Hao Wei-Chong Tang Zhi-Yuan Zheng Zi-Li Zhang School of Science China University of GeosciencesBeijing 100083China

Copper sulfate pentahydrate is investigated by terahertz time-domain spectroscopy. It is shown that the terahertz absorption coefficients are correlated with the particle size of the samples, as well as the heating rates of the ambient temperature. Furthermore, the water molecules of copper sulfate pentahydrate can be quantitatively characterized due to the high sensitivity of the terahertz wave to water molecules. Based on such results, the status of water incorporated in mineral opal is also characterized using terahertz time-domain spectroscopy. It indicates that terahertz technology can be considered as an efficient method to detect the dehydration of minerals.

关键词： copper sulfate pentahydrate water status terahertz time-domain spectroscopy

Investigating path loss characteristics of UWB signals in vacancy indoor environment based on time-domain technique

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Journal of Systems Engineering and Electronics 2006年第2期17卷 296-302页

作者： Wang Yang Zhang Naitong Communication Research Center Harbin Inst. of Technology Harbin 150001 P.R. China

The path loss analysis model based on 5 rays in vacancy indoor environment is proposed. The relationship between multipath overlapping and the path loss is analyzed mathematically. time-domain technique is introduced to compute reflection coefficient in a very short time interval. A 5 rays path loss calculation method, which is satisfactory accurate, is developed. 5 typical environments are involved to analyze and generalize the common path loss characteristics in vacancy indoor environment. The simulation result shows that the path loss can be characterized as 3 zones with different path loss exponent as distance between transmitter and receiver increasing.

关键词： UWB path Loss time-domain multipath indoor environment.

Fast Evaluation of time-domain Green Function for Finite Water Depth

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海洋工程：英文版 2003年第3期17卷 417-426页

作者：滕斌韩凌勾莹 The State Key Laboratory of Coastal and Offshore Engineering

For computation of large amplitude motions of ships fastened to a dock, a fast evaluation scheme is implemented for computation of the time-domain Green function for finite water depth. Based on accurate evaluation of the Green function directly, a fast approximation method for the Green function is developed by use of Chebyshev polynomials. Examinations are carried out of the accuracy of the Green function and its derivatives from the scheme. It is shown that when an appropriate number of polynomial terms are used, very accurate approximation can be obtained.

关键词： Green function time-domain finite water depth

Research on terahertz time-domain spectroscopy methodology of liquid samples

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Science China(Technological Sciences) 2010年第4期53卷 1012-1015页

作者： ZHOU Lei,XU WeiWei,JIN BiaoBing,CHEN Jian,KANG Lin & WU PeiHeng Research Institute of Superconductor Electronics(RISE),Nanjing University,Nanjing 210093,China 1. Research Institute of Superconductor Electronics (RISE) Nanjing University Nanjing 210093 China

Terahertz(THz) time-domain spectroscopy(TDS) has been applied to investigate liquid's optical property in recent ***,comprehensive discussion of how to compute liquids' complex refractive indices and absorption rates ... 详细信息

关键词： terahertz(THz) time-domain spectroscopy(TDS) liquid

Quantum diffraction of wave function in time-domain

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Science China(Physics,Mechanics & Astronomy) 2009年第6期52卷 873-876页

作者： LI YongFang REN LiQing MA RuiQiong QIU Xu LIU Juan FAN Rong FU ZhenXing School of Physics and Information Technology Shaanxi Normal UniversityXi’an 710062China

The transition of a two-level system driven by a linearly weak chirped pulse is studied. Under the first order perturbation approximation, an analytical expression of the population probability is obtained, which is similar to the one describing Fresnel diffraction by a straight edge. It is shown that the population oscillation results from the diffraction of quantum wave function in time-domain.

关键词： wave function quantum diffraction time-domain

An efficient sparse channel estimator combining time-domain LS and iterative shrinkage for OFDM systems with IQ-imbalances

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Science China(Information Sciences) 2012年第11期55卷 2604-2610页

作者： STEVAN Berber Department of Electrical and Computer Engineering University of AucklandAuckland 1142New Zealand

A time-domain(TD) least square(LS) channel estimator is first proposed to estimate channel parameters of OFDM system with IQ imbalances at both transmitter and ***,an iterative shrinkage(IS) algorithm from compressed sensing is adopted to further improve the estimation performance by using the TD-LS solution as the initial value of IS in the case of sparse *** shows that our algorithm combining TD-LS and IS performs better on bit error rate than the frequency-domain LS and matching pursuit in sparse Hilly Terrain channel when the same LS equalizer is adopted.

关键词： iterative shrinkage time-domain least square IQ imbalance channel estimation

time-domain compact macromodeling of linear photonic circuits via complex vector fitting

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Photonics Research 2019年第7期7卷 86-97页

作者： Yinghao Ye Domenico Spina Dirk Deschrijver Wim Bogaerts Tom Dhaene IDLab Department of Information TechnologyGhent University-imecGhentBelgium Photonics Research Group Department of Information TechnologyGhent University-imecGhentBelgium The Center for Nano-and Biophotonics(NB-Photonics) GhentBelgium

In this paper, a novel baseband macromodeling framework for linear passive photonic circuits is proposed, which is able to build accurate and compact models while taking into account the nonidealities,such as higher order dispersion and wavelength-dependent losses of the circuits. Compared to a previous modeling method based on the vector fitting algorithm, the proposed modeling approach introduces a novel complex vector fitting technique. It can generate a half-size state-space model for the same applications, thereby achieving a major improvement in efficiency of the time-domain simulations. The proposed modeling framework requires only measured or simulated scattering parameters as input,which are widely used to represent linear and passive systems. Three photonic circuits are studied to demonstrate the accuracy and efficiency of the proposed technique.

关键词： time-domain compact circuits parameters