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Molecular tagging techniques and their applications to the study of complex thermal flow phenomena

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Acta Mechanica Sinica 2015年第4期31卷 425-445页

作者： Fang chen Haixing Li Hui Hu department of Aerospace Engineering Iowa State University School of Aeronautics & Astronautics Shanghai Jiao Tong University

This review article reports the recent progress in the development of a new group of molecule-based flow diagnostic techniques, which include molecular tag- ging velocimetry （MTV） and molecular tagging thermometry （MTT）, for both qualitative flow visualization of thermally induced flow structures and quantitative whole-field mea- surements of flow velocity and temperature distributions. The MTV and MTT techniques can also be easily combined to result in a so-called molecular tagging velocimetry and ther- mometry （MTV＆T） technique, which is capble of achieving simultaneous measurements of flow velocity and temperature distribution in fluid flows. Instead of using tiny particles, the molecular tagging techniques （MTV, MTT, and MTV＆T） use phosphorescent molecules, which can be turned into long-lasting glowing marks upon excitation by photons of appropriate wavelength, as the tracers for the flow veloc- ity and temperature measurements. The unique attraction and implementation of the molecular tagging techniques are demonstrated by three application examples, which include：（1） to quantify the unsteady heat transfer process from a heated cylinder to the surrounding fluid flow in order to exam- ine the thermal effects on the wake instabilities behind the heated cylinder operating in mixed and forced heat convec- tion regimes, （2） to reveal the time evolution of unsteady heat transfer and phase changing process inside micro-sized, icing water droplets in order to elucidate the underlying physics pertinent to aircraft icing phenomena, and （3） to achievesimultaneous droplet size, velocity and temperature measure- ments of ＂in-flight＂ droplets to characterize the dynamic and thermodynamic behaviors of flying droplets in spray flows.

关键词： Molecular tagging velocimetry Molecular tagging thermometry Wake instabilities behindthe heated cylinder Aircraft icing Icing physics of waterdroplets Dynamics and thermodynamics of flying dropletsin spray flows

Studies on parallel seismic testing for integrity of cemented soil columns

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Journal of Zhejiang university-Science A(Applied physics & Engineering) 2007年第11期8卷 1746-1753页

作者： HUANG Da-zhi chen Long-zhu Institute of Engineering Safety and Disaster Prevention Dept. of Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China

The principle and process of parallel seismic (PS) testing for the integrity testing of cemented soil columns are in- troduced in this paper. A three-dimensional (3D) finite element model (FEM) for the pile-soil system is established for impulse responses. Under saturated soil or unsaturated soil condition, several vibrating velocity-time histories at different depths in parallel hole are obtained based on the numerical simulation. It shows that the length of the pile and the one-dimensional (1D) P-wave velocity in the pile can be determined easily from the features of the mentioned velocity-time histories. By examining the slopes of the first arrival time plotted versus depth or the depth where the amplitude of the first arrival significantly decreases, the length of the pile can be determined. The effects of the 3D P-wave propagation through the saturated soil and the defect of the cemented soil column on the velocity-time histories are also investigated.

关键词： Parallel seismic (PS) testing Cemented soil columns Integrity testing Numerical simulation

Single-Shot Measurement of Broad Bandwidth Terahertz Pulses

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Chinese physics Letters 2012年第1期29卷 191-193页

作者： ZHOU Mu-Lin LIU Feng LI Chun DU Fei LI Yu-tong WANG Wei-Min SHENG Zheng-Ming chen Li-Ming MA Jing-Long LU Xin DONG Quan-Li ZHANG Jie Beijing National Laboratory for Condensed Matter physics Institute of PhysicsChinese Academy of SciencesBeijing 100190 Key Laboratory for Laser Plasmas(Ministry of Education)and department of physics Shanghai Jiao Tong UniversityShanghai 200240

We propose a new single-shot method for measuring terahertz pulses using a linearly chirped optical pulse *** frequency domain phase information can be extracted by the interferogram recorded on imaging *** terahertz pulse waveform is obtained from the phase *** overcome the energy fluctuation problem by using the phase information,making a reference shot unnecessary and the terahertz detection more flexible and convincing.

关键词： pulse overcome phase

Multi-objective genetic algorithm for the optimization of road surface cleaning process

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Journal of Zhejiang university-Science A(Applied physics & Engineering) 2006年第8期7卷 1416-1421页

作者： chen Jie GAO Dao-ming Auto-body Manufacturing Center School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200030 China

The parameters affecting road surface cleaning using waterjets were researched and a fuzzy neural network method of calculating cleaning rate was provided. A genetic algorithm was used to configure the cleaning parameters of pressure, standoff distance, traverse rate and angle of nozzles for the optimization of the cleaning effectiveness, efficiency, energy and water con-sumption, and a multi-objective optimization model was established. After calculation, the optimized results and the trend of variation of cleaning effectiveness, efficiency, energy and water consumption in different weighting factors were analyzed.

关键词： Optimization Waterjets Road surface cleaning Genetic algorithm Multi-objective

基于CT的影像组学诺模图预测结直肠癌肺转移射频消融后的局部肿瘤进展

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中国癌症杂志 2024年第9期34卷 857-872页

作者：黄浩哲陈红郑德重陈超王英许立超王耀辉何新红杨媛媛李文涛复旦大学附属肿瘤医院介入治疗科复旦大学上海医学院肿瘤学系上海200032 上海交通大学医学院附属第六人民医院核医学科上海200233 中国科学院上海技术物理研究所医学影像实验室上海200083

背景与目的:早期预测结直肠癌(colorectal cancer,CRC)肺转移瘤经过射频消融(radiofrequency ablation,RFA)治疗后的局部肿瘤无进展生存期(local tumor progression-free survival,LTPFS)具有重要的临床意义。影像组学在肿瘤预后预测方面已有一定的探索。本研究旨在构建基于影像组学的诺模图预测CRC肺转移患者RFA治疗后的LTPFS。方法:本研究回顾性分析2.16年8月—2.19年1月复旦大学附属肿瘤医院介入治疗科收治的172例伴有401个肺转移病灶的CRC患者。本研究通过复旦大学附属肿瘤医院医学伦理委员会的审查(伦理编号:24022.1-24)。将患者的RFA术前及术后即刻计算机体层成像(computed tomography,CT)图像通过数据增强后,人工分割靶病灶和RFA后区域后提取影像组学特征。采用最大相关最小冗余算法(maximum relevance and minimum redundancy algorithm,MRMRA)和最小绝对值收敛(least absolute shrinkage and selection operator,LASSO)回归模型进行特征筛选。基于筛选后的影像组学特征和多因素分析筛选的临床变量,分别构建临床模型、影像组学模型和融合模型。计算一致性指数(concordance index,C-index)和受试者工作特征(receiver operating characteristic,ROC)曲线的曲线下面积(area under curve,AUC)来评估3种模型的预测性能,最后绘制最佳模型对应的诺模图。结果:在所有肺转移瘤中,最终复发的病灶有102个(25.4%),完全缓解(complete response,CR)的病灶有299个(74.6%)。中位随访时间为21个月(95%CI:19.466~22.534),RFA术后的1、2和3年的LTPFS率分别为76.5%(95%CI:72.0~80.4)、72.1%(95%CI:66.6~76.9)和69.9%(95%CI:64.0~75.1)。无论在训练集还是测试集中,基于LASSO回归模型最终筛选的12个影像组学特征和多因素分析筛选的4个临床变量而构建的融合模型预测LTPFS的AUC最高,C-index分别为0.890(95%CI:0.854~0.927)和0.843(95%CI:0.768~0.916)。结论:基于影像组学特征和临床变量的融合模型预测CRC肺转移患者RFA治疗后的LTPFS是可行的,并且其性能优于单一影像组学模型和临床模型。同时,融合模型的诺模图可以更直观地预测CRC肺转移患者RFA治疗的预后,协助临床医师为患者制订个体化的随访复查方案,灵活地调整治疗策略。

关键词：计算机断层扫描影像组学诺模图结直肠癌肺转移射频消融

A maximum a posteriori super resolution algorithm based on multidimensional Lorentzian distribution

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Journal of Zhejiang university-Science A(Applied physics & Engineering) 2009年第12期10卷 1705-1713页

作者： Wen chen Xiang-zhong FANG Yan chenG shanghai Key Lab of Digital Media Processing and Transmissions Institute of Image Communication and Information Processing Shanghai Jiao Tong University Shanghai 200240 China College of Information Technology East China University of Political Science and Law Shanghai 201620 China

This paper presents a threshold-free maximum a posteriori (MAP) super resolution (SR) algorithm to reconstruct high resolution (HR) images with sharp edges. The joint distribution of directional edge images is modeled as a multidimensional Lorentzian (MDL) function and regarded as a new image prior. This model makes full use of gradient information to restrict the solution space and yields an edge-preserving SR algorithm. The Lorentzian parameters in the cost function are replaced with a tunable variable, and graduated nonconvexity (GNC) optimization is used to guarantee that the proposed multidimensional Lorentzian SR (MDLSR) algorithm converges to the global minimum. Simulation results show the effectiveness of the MDLSR algorithm as well as its superiority over conventional SR methods.

关键词： Edge preservation Multidimensional Lorentzian distribution (MDL) Super resolution Threshold

Production of intense attosecond vector beam pulse trains based on harmonics

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Chinese physics B 2015年第11期24卷 310-313页

作者：韩玉晶廖国前陈黎明李玉同王伟民张杰 Beijing National Laboratory of Condensed Matter physics Institute of Physics Chinese Academy of Science department of physics Heze University IFSA Collaborative Innovation Center Shanghai Jiao Tong University Key Laboratory for Laser Plasmas and department of physics and Astronomy Shanghai Jiao Tong University

We provide the first report on the harmonics generated by an intense femtosecond vector beam that ~s normally mcment on a solid target. By using 2D particle-in-cell （PIC） codes, we observe the third and the fifth harmonic signals with the same vector structure as the driving beam, and obtain an attosecond vector beam pulse train. We also show that the conversion efficiencies of the third and the fifth harmonics reach their maxima for a plasma density of four times the critical density due to the plasma resonating with the driving force. This method provides a new means of generating intense extreme ultraviolet （XUV） vector beams via ultra-intense laser-driven harmonics.

关键词： singular optics laser plasma harmonics

Effective femtosecond laser shock peening on a Mg-3Gd alloy at low pulse energy 430 μJ of 1 kHz

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Journal of Magnesium and Alloys 2019年第3期7卷 529-535页

作者： chenghao Lu Licheng Ge Bing Zhu Yangxin Li Xianfeng chen Xiaoqin Zeng Yuping chen State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240PR China National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composite Shanghai Jiao Tong UniversityShanghai 200240PR China

In this paper,microstructure evolution and hardness of Mg-3 Gd alloy treated by femtosecond(fs)laser shock peening(LSP)with direct and confined ablation m odes were investigated in *** a relatively low pulse energy of 430μJ with a repetition of 1 kHz,the surface hardness of sample has been enhanced by 70%*** a r e d with ns-LSP with pulse fluence of 71.7J/cm2,fs-LSP with pulse fluence of 34.2 J/cm2 is superior in the hardness increment,both of which are in the same order of magnitude.A distinct grain refinement of surface layer has been discovered and results in the increase of *** of absorption and confining layers and the employment of the industry commercial fs laser with high repetition can inspire big potential L S P application in special metal material.©2.19 Published by Elsevier *** behalf of Chongqing university.

关键词： Laser shock peening Femtosecond laser Mg-3Gd alloy hardness Surface treatment

Enhanced search sensitivity to the double beta decay of ^(136)Xe to excited states with topological signatures

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Science china(physics,Mechanics & Astronomy) 2021年第6期64卷 41-50页

作者： chen Xie Kaixiang Ni Ke Han Shaobo Wang Institute of Nuclear and Paricle physics(INPAC) Shanghai Laboratory for Particle Physics and CosmologyKey Laboratory for Partic le Astrophysics and Cosmology(MOE)School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China ParisTech Elite Institute of Technology Shanghai Jiao Tong UniversiryShanghai 200240China

The double beta decay of ^(136)Xe to excited states of 136Ba(DBD-ES)has not yet been discovered *** experimental signature of such decays,one or two gamma rays following the beta signals,can be identified more effectively in a gaseous detector with the help of topological *** have investigated key parameters of particle trajectories of DBD-ES with Monte Carlo simulation data of the proposed PandaX-III detector as an *** background rates can be reduced by about one order of magnitude while keeping more than half of signals with topological *** estimated half-life sensitivity of DBD-ES can be improved by 1.8 times to 4.1×10^(23) year(90%C.L.).Similarly,the half-life sensitivity of neutrinoless double beta decay of ^(136)Xe to excited states of 136Ba can be improved by a factor of 4.8 with topological signatures.

关键词： neutrino double beta decay topological signatures background suppression