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Time-dependent diffusion magnetic resonance imaging:measurement,modeling,and applications

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第10期25卷 765-787页

作者： Ruicheng ba Liyi KANG Dan WU Key Laboratory for Biomedical Engineering of Ministry of Education Department of Biomedical EngineeringCollege of Biomedical Engineering&Instrument ScienceZhejiang UniversityHangzhou 310027China

Increasingly,attention is being directed towards time-dependent diffusion magnetic resonance imaging(TDDMRI),a method that reveals time-related changes in the diffusional behavior of water molecules in biological tissues,thereby enabling us to probe related microstructure *** ongoing improvements in hardware and advanced pulse sequences,significant progress has been made in applying TDDMRI to clinical *** development of accurate mathematical models and computational methods has bolstered theoretical support for TDDMRI and elevated our understanding of molecular *** this review,we introduce the concept and basic physics of TDDMRI,and then focus on the measurement strategies and modeling approaches in short-and long-diffusion-time ***,we discuss the challenges in this field,including the requirement for efficient scanning and data processing technologies,the development of more precise models depicting time-dependent molecular diffusion,and critical clinical applications.

关键词： Time-dependent diffusion Diffusion magnetic resonance imaging(dMRI) Microstructure imaging Microstructural model

Analysis of Heat and Mass Transfer for a Single-Planar-Anode-Supported Solid Oxide Fuel Cell Considering Internal Reforming

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Journal of Thermal Science 2020年第3期29卷 697-707页

作者： ZHANG Zhuqian WANG Yulei ba Liming Institute of Thermal Engineering School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale Beijing 100044China National Institute of Clean-and-Low-Carbon Energy Beijing 102211China

The temperature uniformity and component concentration distributions in solid oxide fuel cells during operating processes can influence the cell electrochemical and thermal characteristics.A three-dimensional thermal-fluid numerical model including electrochemical reactions and water-gas-shift(WGS)reaction for a single channel solid oxide fuel cell was developed to study the steady-state characteristics,which include distributions of the temperature(T),temperature gradient((35)T/(35)x),and fuel *** was shown that the maximum temperature(Tmax)changed with operating voltage and the maximum temperature gradient(((35)T/(35)x)max)occurred at the inlet of the channel of a solid oxide fuel cell by ***,the natural convection condition had a great influence on T and(35)T/(35)*** thermal stress generated by temperature differences was the key parameter and increasing the convection heat-transfer coefficient can greatly reduce the thermal *** addition,the results also showed that there were lower temperature gradients and lower current density at high working voltage;therefore,choosing the proper operating voltage can obtain better cell performance.

关键词： three-dimensional numerical simulation internal reforming reaction solid oxide fuel cell temperature gradient fuel utilization

Comprehensive Evaluation Method for Traffic Flow Data Quality based on Grey Correlation Analysis and Particle Swarm Optimization

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Journal of Systems Science and Systems Engineering 2024年第1期33卷 106-128页

作者： Wei ba baojun Chen Qi Li School of Automation and Electrical Engineering Dalian Jiaotong UniversityDalian116028China Faculty of Electronic Information and Electrical Engineering Dalian University of TechnologyDalian116023China

Nowadays,data are more and more used for intelligent modeling and prediction,and the comprehensive evaluation of data quality is getting more and more attention as a necessary means to measure whether the data are usable or ***,the comprehensive evaluation method of data quality mostly contains the subjective factors of the evaluator,so how to comprehensively and objectively evaluate the data has become a bottleneck that needs to be solved in the research of comprehensive evaluation *** order to evaluate the data more comprehensively,objectively and differentially,a novel comprehensive evaluation method based on particle swarm optimization(PSO)and grey correlation analysis(GCA)is presented in this *** first,an improved GCA evaluation model based on the technique for order preference by similarity to an ideal solution(TOPSIS)is ***,an objective function model of maximum difference of the comprehensive evaluation values is built,and the PSO algorithm is used to optimize the weights of the improved GCA evaluation model based on the objective function ***,the performance of the proposed method is investigated through parameter analysis.A performance comparison of traffic flow data is carried out,and the simulation results show that the maximum average difference between the evaluation results and its mean value(MDR)of the proposed comprehensive evaluation method is 33.24%higher than that of TOPSIS-GCA,and 6.86%higher than that of *** proposed method has better differentiation than other methods,which means that it objectively and comprehensively evaluates the data from both the relevance and differentiation of the data,and the results more effectively reflect the differences in data quality,which will provide more effective data support for intelligent modeling,prediction and other applications.

关键词： Data quality comprehensive evaluation particle swarm optimization grey correlation analysis traffic flow data

A novel hydrogen peroxide-initiated reaction of difluorodiiodomethane with alkynes

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Chinese Journal of Chemistry 1997年第2期15卷 154-159页

作者： Li, ar Chen, QY CHINESE ACAD SCI SHANGHAI INST ORGAN CHEMSHANGHAI 200032PEOPLES R CHINA

The reaction of difluorodiiodomethane with alkynes (4a-e) in the presence of hydrogen peroxide afforded the corresponding beta-iodo-alpha, beta-unsaturated carboxylic acids. When propargylic alcohol was used as the substrate, beta-iodo-alpha,beta-unsaturated gamma-butyrolactone (5F) was produced. The mechanism of the reaction was suggested.

关键词： difluorodiiodomethane addition alkynes hydrogen peroxide

Levels of evidence and grades of recommendation supporting European society for medical oncology clinical practice guidelines

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Oncology Research 2024年第5期32卷 807-815页

作者： MarKO SKELIN BRUNA PERKOV-STIPIČIN SANJA VUŠKOVIĆ MarINAŠANDRK PLEHAČEK ANE baŠIĆ DAVIDŠarČEVIĆ MAJA ILIĆ IVAN KREČAK Pharmacy Department General Hospital ofŠibenik-Knin CountyŠibenikCroatia Faculty of Medicine University of RijekaRijekaCroatia Undergraduate Study in Nursing University of Applied SciencesŠibenikCroatia Department of Oncology University Hospital Center ZagrebZagrebCroatia Pharmacies Joukhadar Sveta NedeljaCroatia Pharmacies Prima Pharme ZagrebCroatia Pharmacy Department General Hospital ZadarZadarCroatia Pharmacy Department General Hospital PulaPulaCroatia Department of Internal Medicine General Hospital ofŠibenik-Knin CountyŠibenikCroatia

background:The European Society for Medical Oncology(ESMO)guidelines are among the most comprehensive and widely used clinical practice guidelines(CPGs)***,the level of scientific evidence supporting ESMO CPG recommendations has not been systematically *** study assessed ESMO CPG levels of evidence(LOE)and grades of recommendations(GOR),as well as their trends over time across various cancer ***:We manually extracted every recommendation with the Infectious Diseases Society of America(IDSA)classification from each *** examined the distribution of LOE and GOR in all available ESMO CPG guidelines across different topics and cancer ***:Among the 1,823 recommendations in the current CPG,30%were classified as LOEⅠ,and 43%were classified as GOR ***,there was a slight decrease in LOEⅠ(−2%)and an increase in the proportion of GOR A(+1%)in the current CPG compared to previous *** proportion of GOR A recommendations based on higher levels of evidence such as randomized trials(LOEⅠ–Ⅱ)shows a decrease(71%vs.63%,p=0.009)while recommendations based on lower levels of evidence(LOEⅢ–Ⅴ)show an increase(29%vs.37%,p=0.01)between previous and current *** the current versions,the highest proportion of LOEⅠ(42%)was found in recommendations related to pharmacotherapy,while the highest proportion of GOR A recommendations was found in the areas of pathology(50%)and diagnostic(50%)*** variability in LOEⅠand GOR A recommendations and their changes over time was observed across different cancer ***:One-third of the current ESMO CPG recommendations are supported by the highest level of *** well-designed randomized clinical trials are needed to increase the proportion of LOEⅠand GOR A recommendations,ultimately leading to improved outcomes for cancer patients.

关键词： ESMO guidelines Clinical practice guidelines Level of evidence Grade of recommendation

雅鲁藏布江下游浮游植物群落构建机制及驱动因素

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湖泊科学 2025年第1期37卷 215-228,I0024页

作者：巢欣杨胜娴刘惠秋闫冰洁卫佩佩吴湘君巴桑西藏大学生态环境学院青藏高原湿地与流域生态系统实验室拉萨850000 西藏大学麦地卡自治区级湿地生态系统定位观测研究站那曲852000 西藏大学地球第三极碳中和研究中心拉萨850000

为探究雅鲁藏布江下游浮游植物群落多样性、构建机制及驱动因子,本文于2022年5月(春季)、2023年7月(夏季)和9月(秋季)对雅鲁藏布江下游34个样点进行了浮游植物样品采集和环境因子的调查,利用显微镜鉴定浮游植物物种,分析该水域浮游植物... 详细信息

为探究雅鲁藏布江下游浮游植物群落多样性、构建机制及驱动因子,本文于2022年5月(春季)、2023年7月(夏季)和9月(秋季)对雅鲁藏布江下游34个样点进行了浮游植物样品采集和环境因子的调查,利用显微镜鉴定浮游植物物种,分析该水域浮游植物群落结构特征,并探究了不同季节浮游植物群落差异及群落构建的驱动因素。结果表明:1)该水域共鉴定出浮游植物269种及变种,隶属于8门10纲22目40科87属,细胞丰度为春季>夏季>秋季,物种数为秋季>春季>夏季,浮游植物群落结构整体呈现硅藻绿藻蓝藻型,共筛选出优势种12种,均为硅藻;2)Shannon多样性指数、Pielou均匀度指数、Simpson多样性指数及Margalef丰富度指数在夏季最低,主坐标分析结果表明浮游植物群落组成在季节上存在差异,通过分析3个季节的β多样性及组分分解得知,这种差异主要来源于周转,且周转组分在春季占比最大;3)中性群落模型及校正化随机率表明,随机性过程主导了雅鲁藏布江下游3个季节浮游植物群落的构建,方差分解分析结果显示地理因子的解释率(10.13%)大于环境因子(7.46%),经度、纬度和海拔是影响浮游植物群落构建的主要地理因子,水温、pH是影响浮游植物群落构建的主要环境因子;4)共现网络分析结果表明浮游植物间的相互作用以协作为主,且秋季的群落结构相较于春季和夏季更精简、稳定。

关键词：浮游植物群落多样性中性模型校正化随机率随机性过程驱动因子雅鲁藏布江下游

Diffraction of SH-waves by topographic features in a layered transversely isotropic half-space

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Earthquake Engineering and Engineering Vibration 2017年第1期16卷 11-22页

作者： ba Zhenning Liang Jianwen Zhang Yanju Department of Civil Engineering Tianjin University Tianjin 300072 China Key Laboratory of Coast Civil Structure Safety ( Tianjin University) Ministry of Education Tianjin 300072 China

Abstract： The scattering of plane SH-waves by topographic features in a layered transversely isotropic （TI） half-space is investigated by using an indirect boundary element method （IBEM）. Firstly, the anti-plane dynamic stiffness matrix of the layered TI half-space is established and the free fields are solved by using the direct stiffness method. Then, Green＇s functions are derived for uniformly distributed loads acting on an inclined line in a layered TI half-space and the scattered fields are constructed with the deduced Green＇s functions. Finally, the free fields are added to the scattered ones to obtain the global dynamic responses. The method is verified by comparing results with the published isotropic ones. Both the steady-state and transient dynamic responses are evaluated and discussed. Numerical results in the frequency domain show that surface motions for the TI media can be significantly different from those for the isotropic case, which are strongly dependent on the anisotropy property, incident angle and incident frequency. Results in the time domain show that the material anisotropy has important effects on the maximum duration and maximum amplitudes of the time histories.

关键词： wave scattering and diffraction Green's function transversely isotropic SH-waves indirect boundaryelement method

P-wave velocity prediction in porous medium with liquid-pocket patchy saturation

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Applied Mathematics and Mechanics(English Edition) 2015年第11期36卷 1427-1440页

作者： Jiawei LIU Weitao SUN Jing ba Zhou Pei-Yuan Center for Applied Mathematics Tsinghua University Department of Computational Geophysics Xi'an Jiaotong University

It becomes increasingly clear that non-uniform distribution of immiscible fluids in porous rock is particularly relevant to seismic wave dispersion. White proposed a patchy saturation model in 1975, in which spherical gas pockets were located at the center of a liquid saturated cube. For an extremely light and compressible inner gas, the physical properties can be approximated by a vacuum with White＇s model. The model successfully analyzes the dispersion phenomena of a P-wave velocity in gas-water- saturated rocks. In the case of liquid pocket saturation, e.g., an oil-pocket surrounded by a water saturated host matrix, the light fluid-pocket assumption is doubtful, and few works have been reported in White＇s framework. In this work, Poisson＇s ratio, the bulk modulus, and the effective density of a dual-liquid saturated medium are formulated for the heterogeneous porous rocks containing liquid-pockets. The analysis of the difference between the newly derived bulk modulus and that of White＇s model shows that the effects of liquid-pocket saturation do not disappear unless the porosity approaches zero. The inner pocket fluid can no longer be ignored. The improvements of the P-wave velocity predictions are illustrated with two examples taken from experiments, i.e., the P-wave velocity in the sandstone saturated by oil and brine and the P-wave velocity for heavy oils and stones at different temperatures.

关键词： White's model porous medium P-wave dispersion liquid pocket

In-plane dynamic Green's functions for inclined and uniformly distributed loads in a multi-layered transversely isotropic half-space

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Earthquake Engineering and Engineering Vibration 2018年第2期17卷 293-309页

作者： ba Zhenning Kang Zeqing Liang Jianwen Department of Civil Engineering Tianjin UniversityTianjin 300072China Key Laboratory of Coast Civil Structure Safety(Tianjin University) Tianjin 300072China

The dynamic stiffness method combined with the Fourier transform is utilized to derive the in-plane Green’s functions for inclined and uniformly distributed loads in a multi-layered transversely isotropic（TI）*** loaded layer is fixed to obtain solutions restricted in it and the corresponding reactions forces,which are then applied to the total system with the opposite *** adding solutions restricted in the loaded layer to solutions from the reaction forces,the global solutions in the wavenumber domain are obtained,and the dynamic Green’s functions in the space domain are recovered by the inverse Fourier *** presented formulations can be reduced to the isotropic case developed by Wolf（1985）,and are further verified by comparisons with existing solutions in a uniform isotropic as well as a layered TI halfspace subjected to horizontally distributed loads which are special cases of the more general problem *** deduced Green’s functions,in conjunction with boundary element methods,will lead to significant advances in the investigation of a variety of wave scattering,wave radiation and soil-structure interaction problems in a layered TI *** numerical results are given to investigate the influence of material anisotropy,frequency of excitation,inclination angle and layered on the responses of displacement and stress,and some conclusions are drawn.

关键词： Green's functions transversely isotropic medium multi-layered half-space stiffness method dynamic response