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Dynamics of Charged Ring Polymers under Gel Confinement
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作者 Lu-Jie Huo Kai-Ru Qu +1 位作者 Zhen-Zhong Yang Di Jia 《Chinese Journal of Polymer Science》 2025年第3期399-405,共7页
Ring polymers are ubiquitous in various fields including biomaterials,drug release and gene therapy.All of these applications involve the dynamics and diffusion process of ring polymers in a confined environment.By us... Ring polymers are ubiquitous in various fields including biomaterials,drug release and gene therapy.All of these applications involve the dynamics and diffusion process of ring polymers in a confined environment.By using dynamic light scattering(DLS),we discovered a dynamical transition for charged ring polymers with increasing ring concentration in the gel matrix from a diffusive state to a non-diffusive topological frustrated state with a more compact conformation.When the ring polymer size is smaller than the mesh size of the gel matrix,the rings are diffusive at low concentration of 5 g/L.The ring diffusion coefficient in the gel matrix is an order of magnitude smaller than that of rings in solution,obeying the Ogston's model.At high ring concentration of 40 g/L,the collective dynamical behavior of the charged rings exhibits a topologically frustrated non-diffusive state,which may originate from the inter-ring threading with the external confinement from the gel matrix.Based on our previous theoretical work,we also conjectured that in such a non-diffusive state,the ring polymers might adopt a more compact conformation with the overall size exponentν=1/3. 展开更多
关键词 Charged ring polymer Dynamics under confinement non-diffusive topologically frustrated dynamics Dynamic light scattering Collective diffusion coefficient
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基于非高斯分布模型的扩散加权成像在体部疾病中的应用 被引量:12
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作者 王科 潘婷 +1 位作者 周欣 吴光耀 《磁共振成像》 CAS CSCD 2016年第1期71-76,共6页
常规扩散加权成像(DWI)在超高b值时,单指数模型不再适用,细胞外间隙水分子的扩散偏离高斯分布,需要更复杂的模型来分析这种非高斯扩散。扩散峰度成像(DKI)能描述水分子的这种非高斯扩散行为,得到额外的参数K_(app),K_(app)不仅能反映组... 常规扩散加权成像(DWI)在超高b值时,单指数模型不再适用,细胞外间隙水分子的扩散偏离高斯分布,需要更复杂的模型来分析这种非高斯扩散。扩散峰度成像(DKI)能描述水分子的这种非高斯扩散行为,得到额外的参数K_(app),K_(app)不仅能反映组织细胞界面数,还有反映组织细胞微观结构的异质性和不规则性的潜能。近年来DKI在脑外的研究渐多,尤其是在前列腺,研究显示DKI能提高肿瘤检测和准确分级。放射科医师对DKI模型及其参数的准确理解,有助于评估肿瘤环境、肿瘤分型以及治疗反应。作者旨在综述体部非高斯扩散模型DKI的基本原理、生物学相关性、技术要点及在体部中的临床应用。 展开更多
关键词 非高斯分布 弥散磁共振成像 弥散峰度成像 人体
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扩散峰度成像(DKI)在体部应用的研究进展 被引量:13
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作者 周洋 徐鹏举 《复旦学报(医学版)》 CAS CSCD 北大核心 2018年第6期911-915,920,共6页
扩散峰度成像(diffusion kurtosis imaging,DKI)作为一种新兴的扩散磁共振技术,以非高斯分布模型为基础,相比传统弥散技术即弥散加权成像(diffusion weighted imaging,DWI)和扩散张量成像(diffusion tensor imaging,DTI),对探测水分子... 扩散峰度成像(diffusion kurtosis imaging,DKI)作为一种新兴的扩散磁共振技术,以非高斯分布模型为基础,相比传统弥散技术即弥散加权成像(diffusion weighted imaging,DWI)和扩散张量成像(diffusion tensor imaging,DTI),对探测水分子在人体微环境内的扩散运动更加敏感,提供更丰富的扩散信息。DKI最初主要应用于中枢神经系统,近几年在体部应用方面也取得了初步结果。本文主要综述DKI的原理及其在体部的应用现状和展望。 展开更多
关键词 扩散峰度成像(DKI) 非高斯扩散 峰度
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π-phase-shifted two-plus-one method for non-diffuse surface
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作者 王建华 杨延西 徐鹏 《Chinese Optics Letters》 SCIE EI CAS CSCD 2023年第10期36-43,共8页
We propose a method for reconstructing non-diffuse surfaces based on theπ-phase-shifted two-plus-one phase-shifting method.First,we introduce a 2fH+a+2fM+2f_(L)method for unwrapped phase extraction.Subsequently,we in... We propose a method for reconstructing non-diffuse surfaces based on theπ-phase-shifted two-plus-one phase-shifting method.First,we introduce a 2fH+a+2fM+2f_(L)method for unwrapped phase extraction.Subsequently,we introduce a new set ofπ-phase-shifted 2fH+a/2+2fM+2f_(L)fringe patterns with halved background intensity.The saturated pixels will be replaced with the unsaturated pixels in theπ-phase-shifted fringe patterns.Finally,we analyze eight fringe replacement cases and give the corresponding phase calculation,and further give the general formulas.Experiments confirm that the sum of the phase error of the proposed method is 81.4%lower than that of the traditional method,and 61.5%lower than that of the adaptive fringe projection method. 展开更多
关键词 non-diffusion π-phase shift two-plus-one phase shift
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