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New theory on turbulence generation and structure—DNS and experiment

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Science China(Physics,Mechanics & Astronomy) 2017年第8期60卷 82-84页

作者： ChaoQun Liu xiaoshu cai Department of Mathematics University of Texas at Arlington School of Energy and Power Engineering University of Shanghai for Science and Technology

（1） Turbulence is a world puzzle. After over one century re- search effort, ＂Turbulence＂ is still a world puzzle （Wikipedia website at http：//***/wiki/Turbulence）. Nobel Laureate Richard Feynman described turbulence as ＂the most important unsolved problem of classical physics＂. According to an apocryphal story, Werner Heisenberg was asked what he would ask God, given the opportunity. His reply was：＂When I meet God, I am going to ask him two questions： Why rel- ativity？ And why turbulence？ I really believe he will have an answer for the first.＂ Horace Lamb was quoted as saying in a speech to the British Association for the Advancement of Science.

关键词：湍流 Heisenberg DNS 诺贝尔经济学奖实验结构经典物理学 http

Real prospects for the development of power technologies based on renewable energy sources in Poland

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Frontiers in Energy 2017年第2期11卷 168-174页

作者： Slawomir DYKAS Artur SZYMANSKI xiaoshu cai Silesian University of Technology Institute of Power Engineering andTurbomachinery Konarskiego 20 44-100 Gliwice Poland Institute of Particle and Two-Phase Flow Measurement University ofShanghai for Science and Technology Shanghai 200093 China

In Poland more than 40% of the power units have been operating for over 40 years now and more than 10% are over 50 years old, which indicates a high degree of decrease in the value of the energy sector. An analysis of the energy market shows that every year a new power plant should be built with a capacity of 1000 MW to ensure the national energy security. An energy market research indicates that in Poland the structure of energy production is changing in recent years-the share of fossil (solid) fuels in electricity and heat production was approximately 88% in 2009, while in 2004 it reached 93%. According to the analysis of the market, it can be seen that conventional energy, mainly based on coal and lignite, has been the most important segment of the sector for a long time. In this paper the prospects for the development of power technologies based on renewable energy sources (RES) in Poland are presented.

关键词： renewable energy sources energy sector energy mix Poland

Two-dimensional self-adapting fast Fourier transform algorithm for nanoparticle sizing by ultrafast image-based dynamic light scattering

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Particuology 2018年第6期16卷 74-84页

作者： Dechuan Zhang xiaoshu cai Wu Zhou Institute of Particle and Two-Phase Flow Measurement University of Shanghai for Sdence and TechnologyShanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering (University of Shanghai for Sdence and Technology)Shanghai 200093China

In nanoparticle sizing using the ultrafast image-based dynamic light scattering (UIDLS)method,larger impurities and dark noise from the complementary metal-oxide-semiconductor (CMOS)detector affect measurement *** solve this problem,a two-dimensional self-adapting fast Fourier transform (2D-SAFFT)algorithm is proposed for *** light scattering images of nanoparticles are processed using 2D fast Fourier transforms,and a high-frequency threshold and a low-frequency threshold are then set using the self-adapting algorithm to eliminate the effects of the dark noise of the CMOS detector and the *** signals caused by the dark noise of the CMOS detector and the impurities are cut off using the high-frequency threshold and the low-frequency *** signals without the high- and low-frequency components are then processed again using an inverse Fourier transform to obtain new images without the dark noise and impurities *** mean diameters of the measured nanoparticles can be obtained from images obtained using *** standard latex nanoparticles (46,100, 203,508,994nm)and commercial nanoparticles (antimony-doped tin oxide,indium tin oxide,TWEEN- 80,nano-Fe,and nano-Al2O3)were measured using this new *** show that 2D-SAFFT can effectively eliminate the effects of dark noise from the CMOS detector and the impurities.

关键词： Dynamic light scattering Nanoparticle size Fast Fourier transform algorithm Spectrum segmentation

Resonance scattering characteristics of double-layer spherical particles

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Particuology 2012年第1期10卷 117-126页

作者： Xuejin Dong Mingxu Su xiaoshu cai Institute of Particle and Two-Phase Flow Measurement University of Shanghai for Science and Technology Shanghai 200093 China

Based on the principle of ultrasonic resonance scattering, sound-scattering characteristics of double-layer spherical particles in water were numerically studied in this paper. By solving the equations of the scat- tering matrix, the scattering coefficient determined by the boundary conditions can be obtained, thus the expression for the sound-scattering function of a single double-layer spherical particle can be derived. To describe the resonance scattering characteristics of a single particle, the reduced scattering cross section and reduced extinction cross section curves were found through numerical calculation. Similarly, the numerically calculated sound attenuation coefficient curves were used to depict the resonance scattering characteristics of monodisperse and poIydisperse particles. The results of numerical calculation showed that, for monodisperse particles, the strength of the resonance was mainly related to the particle size and the total number of particles; while for polydisperse particles, it was primarily affected by the particle size, the coverage of the particle size distribution and the particle concentration.

关键词： UltrasonicResonance scatteringDouble-layerPolydisperseVisco-elastic

Polarized imaging dynamic light scattering for simultaneous measurement of nanoparticle size and morphology

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Particuology 2024年第2期85卷 213-223页

作者： Bingyao Wang Tianyi cai xiaoshu cai Wu Zhou Zeqi Liu Schoolof Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai200093China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai200093China Jiaxing MeaParTech Instrument Technology Co. LtdZhejiang314000China

The performance of nanoparticles is often affected by particle size and ***,electron microscopy or atomic force microscopy is typically utilized to determine the size and morphology of ***,there are issues such as difficult sample preparation,long processing times,and challenges in quantitative ***,it is of great significance to develop a fast,accu-rate,and statistical method to measure the size and morphology of *** this study,a new method,called polarized imaging dynamic light scattering(PIDLS),is *** nanoparticles are irradiated with a vertical linearly polarized laser beam,and a polarization camera collected the dynamic light scattering images of particles at four different polarization directions(0°,45°,90°,and 135°)at a scattering angle of 90°.The average particle size and distribution are obtained using the imaging dy-namic light scattering method at 0°polarization direction,and the morphology of the particles is ob-tained based on the depolarization patterns of the scattered *** optical sphericityΦis defined based on the degree of linear polarization(DoLP).It is also implemented for the quantitative evaluation of the sphericity of the nanoparticles,including spherical,octahedral,nanoplate,nanorod,and linear *** with the Poincarésphere parameterψ,the morphology of the nanoparticles can be roughly *** addition,PIDLS enables the measurement of particle size and morphology distributions simultaneously for evaluating the uniformity of *** effectiveness of PIDLS is verified by the measurement of five kinds of industrial titanium dioxide as well.

关键词： Imaging dynamic light scattering Polarized light scattering Non-spherical nanoparticles Morphology Online measurement

Estimation of particle depth from two defocused images using the Fourier transform

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Particuology 2020年第2期18卷 48-54页

作者： Wu Zhou Xu Luo Benting Chen Yukun Zhang xiaoshu cai School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai 200093China

Depth from defocus is one technology for depth *** estimate particle depth information from two defocused images captured simultaneously by two coaxial cameras with different imaging *** images are processed with the Fourier transform to obtain the characteristic parameter(i.e.,the standard deviation of the relative blur kernel of these two defocused images).First,we theoretically analyze the functional relationship between the object depth and the standard deviation or variation of the relative blur ***,we verify the relationship *** analyze the influence of particle size,window size and image noise on the calibration curves using both numerical simulations and *** obtain the depth range and accuracy of this measurement system *** the verification experiments,we use a sample of glass microbeads and the irregularly-shaped dust particles on a microscope *** of these experiments present a suitable depth measurement ***,we apply the measuring system to the depth estimation of drops from a small anti-fogging *** results show that our system and image processing algorithm are robust for different types of particles,facilitating the in-line three-dimensional positioning of particles.

关键词： Depth from two defocused images Fourier transform Standard deviation of relative blur kernel Drops depth measurement Sensitivity and accuracy analysis

纳米颗粒粒径、形貌及大体积分数颗粒粒径测量

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中国粉体技术 2025年第1期31卷 118-129页

作者：刘泽奇仪显亨蔡天意蔡小舒上海理工大学能源与动力工程学院上海200093 嘉兴美帕克仪器科技有限公司浙江嘉兴314200

【目的】准确、快速测量纳米颗粒的粒径、形貌,同时避免颗粒体积分数过高对测量结果的影响。【方法】采用3种新的纳米颗粒测量方法图像动态光散射法、偏振图像动态光散射法、大体积分数纳米颗粒180°光纤后向动态光散射法,分别快速测量... 详细信息

【目的】准确、快速测量纳米颗粒的粒径、形貌,同时避免颗粒体积分数过高对测量结果的影响。【方法】采用3种新的纳米颗粒测量方法图像动态光散射法、偏振图像动态光散射法、大体积分数纳米颗粒180°光纤后向动态光散射法,分别快速测量纳米颗粒的粒径及分布、形貌及分布、大体积分数纳米颗粒的粒径;利用基于不同测量方法研制的3种仪器测量多种纳米颗粒,包括球形、非球形和工业纳米颗粒样品。【结果】图像动态光散射法可以快速准确地测量纳米颗粒的粒径,光纤后向动态光散射法可以测量体积分数高达20%的纳米颗粒粒径;对于非球形纳米颗粒,采用光学球体度表征颗粒形貌,偏振图像动态光散射法可以快速测出颗粒的光学球体度和光学球体度分布,用于表征被测颗粒偏离球体的程度,以及非球形纳米颗粒形貌的一致性;非球形颗粒形状偏离球体越远,光学球体度值越小,光学球体度分布越窄,表明非球形纳米颗粒的形貌越均匀。【结论】使用这3种纳米颗粒测量仪器可以实现纳米颗粒粒径的实时测量、纳米颗粒的形貌测量以及高体积分数纳米颗粒的在线测量,可以应用于药物生产的实时监测、化学样品的工艺分析、磨料颗粒的性能评估等方面。

关键词：纳米颗粒粒径分布形貌分布多次散射动态光散射

Fast nanoparticle sizing by image dynamic light scattering

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Particuology 2015年第2期13卷 82-85页

作者： Chengze Xu xiaoshu cai Jie Zhang Lili Liu Institute of Particle and Two-Phase Flow Measurement University of Shanghai for Science and Technology

In this paper, an image dynamic light scattering method for nanoparticle sizing is introduced. The spatial distribution of the scattered lights from nanoparticles undergoing Brownian motion was captured at a high frame rate by a digital camera within one second, which is considerably faster than the conven- tional photon correlation spectroscopy method. The captured series of photographs were meshed into thousands of small units for calculating the intensity autocorrelation functions in parallel. Experimental results from the measurements of three reference nanoparticle samples （27, 80, and 352 nm in diameters） demonstrated the feasibility of this method.

关键词： Nanoparticle sizing Image dynamic light scattering Real-time acquisition Brownian motion

In-line imaging measurements of particle size,velocity and concentration in a particulate two-phase flow

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Particuology 2014年第2期12卷 106-113页

作者： Xiaozhen Chen Wu Zhou xiaoshu cai Mingxu Su Hailong Liu Institute of Particle and Two-phase Flow Measurement University of Shanghai for Science and Technology

A novel method is developed for in-line measurements of particle size, velocity and concentration in a dilute, particulate two-phase flow based on trajectory image processing. The measurement system consists of a common industrial CCD camera, an inexpensive LED light and a telecentric lens. In this work, the image pre-processing steps include stitching, illumination correction, binarization, denoising, and the elimination of unreal and defocused particles. A top-hat transformation is found to be very effective for the binarization of images with non-uniform background illumination. Particle trajectories measured within a certain exposure time are used to directly obtain particle size and velocity. The particle concentration is calculated by using the statistics of recognized particles within the field of view. We validate our method by analyzing experiments in a gas-droplet cyclone separator. This in-line image processing method can significantly reduce the measurement cost and avoid the data inversion process involved in the light scattering method.

关键词： In-line measurements Particle trajectory Image processing Multi-parameters