Adopting ＂simultaneous transmitting, simultaneous receiving＂ operational scheme, instantaneous polarization radar （IPR） can measure target polarization scattering matrix （PSM） using only once target echoes in tw...Adopting ＂simultaneous transmitting, simultaneous receiving＂ operational scheme, instantaneous polarization radar （IPR） can measure target polarization scattering matrix （PSM） using only once target echoes in two orthogonal polarization channels. Firstly, signal model and signal process are advanced under narrowband condition. Secondly, measurement performances of two typical IPR waveforms are analyzed in detail. At last, field experiments are carried out using X-band IPR system designed by National University of Defense Technology （NUDT）, China. Compared with results obtained by alternative polarization measurement scheme, following results can be obtained： the difference of relative amplitude measurement results is smaller than 2 dB and that of relative phase measurement results is smaller than 10？, verifying the validity of instantaneous polarization measurement scheme.展开更多
In this paper, a theoretical model of multi-level, non-spherical scatterers is developed for fully polarimetric scattering from tree canopy in SAR imaging at C band. The amplitude functions of non-spherical particles ...In this paper, a theoretical model of multi-level, non-spherical scatterers is developed for fully polarimetric scattering from tree canopy in SAR imaging at C band. The amplitude functions of non-spherical particles with randomly spatial orientation are derived by the generalized Rayleigh-Gans (GRG) approximation. The non-diagonal extinction matrix and the Mueller matrix solution are constructed. Numerical solutions of polarimetric scattering of four Stokes parameters from random, non-spherical scatterers are obtained. To physically identify polarimetric scattering of the Mueller matrix solution, the coherency matrix and its eigen-analysis are discussed. Functional dependence of the coherency matrix and entropy upon various parameters are obtained. As an application, the analysis of AirSAR images at P, L, C bands is discussed.展开更多
This study introduces a comprehensive theoretical framework for accurately calculating the electronic band-structure of strained long-wavelength InAs/GaSb type-Ⅱsuperlattices.Utilizing an eight-band k·p Hamilto⁃...This study introduces a comprehensive theoretical framework for accurately calculating the electronic band-structure of strained long-wavelength InAs/GaSb type-Ⅱsuperlattices.Utilizing an eight-band k·p Hamilto⁃nian in conjunction with a scattering matrix method,the model effectively incorporates quantum confinement,strain effects,and interface states.This robust and numerically stable approach achieves exceptional agreement with experimental data,offering a reliable tool for analyzing and engineering the band structure of complex multi⁃layer systems.展开更多
表面增强拉曼散射(SERS)技术在生物基质(如尿液、血液、唾液和毛发)中用于兴奋剂初筛的最新研究展现了显著的应用潜力。通过对Web of Science、PubMed和Scopus等数据库近十年相关文献的系统检索,筛选出符合以下标准的研究:(1)研究对象...表面增强拉曼散射(SERS)技术在生物基质(如尿液、血液、唾液和毛发)中用于兴奋剂初筛的最新研究展现了显著的应用潜力。通过对Web of Science、PubMed和Scopus等数据库近十年相关文献的系统检索,筛选出符合以下标准的研究:(1)研究对象涉及使用SERS检测尿液、血液、唾液或毛发中的兴奋剂;(2)采用金、银等功能化纳米基底;(3)文献来源于权威期刊,以确保科学性和可靠性;(4)报告灵敏度、选择性、重现性和实际检测效果。结果显示,SERS技术在兴奋剂初筛检测中表现出高灵敏度、快速检测和无损分析的优势,但在检测的重现性和特异性方面仍面临挑战,复杂样本中的基质效应可能干扰检测信号。因此,SERS在兴奋剂检测领域的发展应重点优化多功能基底设计和标准化样品处理流程,同时结合人工智能技术与液相色谱质谱(LC-MS)等方法,实现复杂光谱数据的高效分析和多组分联合检测。通过推进便携式设备的研发,可进一步满足现场快速检测的需求。展开更多
基金supported by the National Natural Science Foundationof China (60736006 60802078)
文摘Adopting ＂simultaneous transmitting, simultaneous receiving＂ operational scheme, instantaneous polarization radar （IPR） can measure target polarization scattering matrix （PSM） using only once target echoes in two orthogonal polarization channels. Firstly, signal model and signal process are advanced under narrowband condition. Secondly, measurement performances of two typical IPR waveforms are analyzed in detail. At last, field experiments are carried out using X-band IPR system designed by National University of Defense Technology （NUDT）, China. Compared with results obtained by alternative polarization measurement scheme, following results can be obtained： the difference of relative amplitude measurement results is smaller than 2 dB and that of relative phase measurement results is smaller than 10？, verifying the validity of instantaneous polarization measurement scheme.
文摘In this paper, a theoretical model of multi-level, non-spherical scatterers is developed for fully polarimetric scattering from tree canopy in SAR imaging at C band. The amplitude functions of non-spherical particles with randomly spatial orientation are derived by the generalized Rayleigh-Gans (GRG) approximation. The non-diagonal extinction matrix and the Mueller matrix solution are constructed. Numerical solutions of polarimetric scattering of four Stokes parameters from random, non-spherical scatterers are obtained. To physically identify polarimetric scattering of the Mueller matrix solution, the coherency matrix and its eigen-analysis are discussed. Functional dependence of the coherency matrix and entropy upon various parameters are obtained. As an application, the analysis of AirSAR images at P, L, C bands is discussed.
文摘This study introduces a comprehensive theoretical framework for accurately calculating the electronic band-structure of strained long-wavelength InAs/GaSb type-Ⅱsuperlattices.Utilizing an eight-band k·p Hamilto⁃nian in conjunction with a scattering matrix method,the model effectively incorporates quantum confinement,strain effects,and interface states.This robust and numerically stable approach achieves exceptional agreement with experimental data,offering a reliable tool for analyzing and engineering the band structure of complex multi⁃layer systems.
文摘表面增强拉曼散射(SERS)技术在生物基质(如尿液、血液、唾液和毛发)中用于兴奋剂初筛的最新研究展现了显著的应用潜力。通过对Web of Science、PubMed和Scopus等数据库近十年相关文献的系统检索,筛选出符合以下标准的研究:(1)研究对象涉及使用SERS检测尿液、血液、唾液或毛发中的兴奋剂;(2)采用金、银等功能化纳米基底;(3)文献来源于权威期刊,以确保科学性和可靠性;(4)报告灵敏度、选择性、重现性和实际检测效果。结果显示,SERS技术在兴奋剂初筛检测中表现出高灵敏度、快速检测和无损分析的优势,但在检测的重现性和特异性方面仍面临挑战,复杂样本中的基质效应可能干扰检测信号。因此,SERS在兴奋剂检测领域的发展应重点优化多功能基底设计和标准化样品处理流程,同时结合人工智能技术与液相色谱质谱(LC-MS)等方法,实现复杂光谱数据的高效分析和多组分联合检测。通过推进便携式设备的研发,可进一步满足现场快速检测的需求。
