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Plume dynamics and dispersion characteristics in oil horizontal release from damaged submarine pipeline

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Chinese Journal of Chemical Engineering 2020年第5期28卷 1214-1224页

作者： Jun Zhang Hongzhou He Shaohui Yang Fujian Province Key Laboratory of Energy Cleaning Utilization and Development Xiamen 361021China Key Laboratory of Ocean Renewable Energy Equipment School of Mechanical EngineeringJimei UniversityXiamen 361021China

The dynamics model of plume for underwater oil spill is improved by considering the drag force of the *** comparisons between prediction and experiment show that the improved model is *** improved model combining the Lagrangian random walk method is used to simulate the entire oil transport process from release exit to water surface in underwater oil horizontal release and some new results are ***,the release rate,the current velocity and its direction have evident influence on plume *** plume length increases as release flow rate *** small oil release rate,the plume length is very short so that the plume stage can be ignored due to the small initial *** the oil release in direction is the same as the current,the current will play a positive role in the plume motion and the plume will therefore extend a longer *** this case,the greater the current velocity is,the longer the plume extension length will *** when the oil release in direction is opposite to the current,the plume first moves forward and then is reversed to move along the opposite *** position of the reversal point depends on the current velocity and the release ***,the release rate and the current velocity also have a significant effect on oil droplet *** small oil release rate,the oil distribution area is narrow and the concentration near upper side of droplets moving path is relatively *** the release rate or current velocity increases,the oil droplet diffusion area expands away from the release ***,the movement characteristics of oil droplets in the plume and diffusion stages will affect the time and location for oil droplets reaching the *** a small release rate as well as a small current velocity,the time for oil droplet reaching surface is very short and the horizontal position reaching surface is closer to release *** this case,the time spent in the plume stage is extremely s

关键词： Submarine pipeline Plume dynamics dispersion characteristics Simulation

Discussion on“dispersion characteristics of clayey soils containing waste rubber particles”[J Rock Mech Geotech Eng 15(2023)3050-3058]

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3864-3865页

作者： Prithvendra Singh Devendra Narain Singh Pintu Kumar Saw Department of Civil Engineering Indian Institute of Technology BombayMumbai400076India

We read with great interest the recent article by Erenson(2023)entitled“dispersion characteristics of clayey soils containing waste rubber particles”.The author has studied the dispersion characteristics of clayey soils containing different percentages of waste rubber particles(WRPs)by performing several tests(*** limit,linear shrinkage limit,double hydrometer,crumb test and pinhole test)and scanning electron microscopy(SEM)analysis on five clayey(***-activated bentonite,refined ball clay,Ukrainian kaolin,Avanos kaolin and Afyon clay)samples containing 0%,5%,10%and 15%*** should be noted that Erenson(2023)has presented some interesting observations,but there are some serious issues that we want to share through this discussion and request the author of the original paper to address them to avoid their persistence in the scientific literature.

关键词： Waste rubber particles dispersion characteristics Clay Bentonite Scientific literature Discussion

Comparative research on three types of coaxial slow wave structures

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Chinese Physics B 2008年第10期17卷 3807-3811页

作者：肖仁珍刘国治陈昌华 Northwest Institute of Nuclear Technology

This paper studies three types of coaxial slow wave structures （SWSs）：（1） with ripples on both the inner and outer conductors; （2） with ripples on the outer conductor and smooth on the inner one; and （3） with ripples on the inner conductor and smooth on the outer one. The frequencies, coupling impedances, time growth rates and beam-wave interaction efficiencies of the three types of coaxial SWSs are obtained by theoretical analysis. Moreover, the relativistic Ccrenkov generators （RCGs） with the three types of coaxial SWSs are simulated with a fully electromagnetic particle- in-cell code, and the results verify the theoretical analysis. It is proved that the RCG with double-rippled coaxial SWS has the highest conversion efficiency and the shortest starting time.

关键词： relativistic Cerenkov generator coaxial slow wave structure dispersion characteristics particle-in-cell simulation

An open-styled dielectric-lined azimuthally periodic circular waveguide for a millimeter wave traveling-wave tube

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Chinese Physics B 2012年第4期21卷 597-604页

作者：刘漾魏彦玉徐进殷海荣岳玲娜宫玉彬王文祥 Vacuum Electronics National Laboratory School of Physical ElectronicsUniversity of Electronic Science and Technology of ChinaChengdu 610054China

An open-styled dielectric-lined azimuthMly periodic circular waveguide （ODLAP-CW） for a millimeter-wave traveling-wave tube （TWT） is proposed, which is a modified form of a dielectric-lined azimuthally periodic circular waveguide （DLAP-CW）. The slow-wave characteristics of the open-styled DLAP-CW are studied by using the spatial harmonics method, which includes normalized phase velocity and interaction impedance. The complicated dispersion equations are numerically solved with MATLAB and the results are in good agreement with the simulation results obtained from HFSS. The influence of structural parameters on the RF properties is investigated based on our theory. The numerical results show that the optimal thickness of the metal rod can increase the interaction impedance, with the dielectric constant held fixed. Finally, the slow-wave characteristics and transmission properties of an open-styled structure are compared with those of the DLAP-CW. The results validate that the mode competition is eliminated in the improved structure with only a slight influence on the dispersion characteristics, which may significantly improve the stability of an open-styled DLAP-CW-based TWT, and the interaction efficiency is also improved.

关键词： dispersion characteristics slow-wave structure millimeter wave traveling-wave tube spa- tial harmonics method

Variational analysis of the disc-loaded waveguide slow-wave structures

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Chinese Physics B 2005年第11期14卷 2300-2304页

作者：李建清莫元龙 School of Physical Electronics University of Electronic Science and Technology of China Chengdu 610054 China

The variational method is applied to calculate the dispersion characteristics of disc-loaded waveguide slow-wave structures. The parameters describing the waveguide discontinuities in disc-loaded waveguide are calculated by the variational method. Then the dispersion characteristics of slow-wave structures are obtained using lossless microwave quadrupole theory. Good agreement was observed between results of the Variational method and those of field matching method and high frequency structure simulator. In the case of broad band, results of the variational method are better than those of field matching method.

关键词： variational method disc-loaded waveguide slow-wave structures dispersion characteristics

Research on the Characteristic of the Disk-Loaded Waveguide, Rib-Loaded Disk-Loaded Waveguide and Helix Slow-Wave Structures

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Journal of Electronic Science and Technology of China 2005年第2期3卷 188-189页

作者： ZHANGYong SchoolofPhysicalElectronicsUniversityofElectronicScienceandTechnologyofChinaChengdu610054China

The fast development of modern electronic warfare, broadband high power array radar system, high power jammer and microwave directional power weapon imposes high demand on high power microwave resource. With such features as high power, broadband, multi-mode, etc., traveling wave tubes (TWTs) play an important role in the high power microwave amplifiers. Since the slow-wave system is the core of beam-wave interaction in TWTs, the function and performance of it directly determine the capability of the TWTs.

关键词： traveling wave tube disk-loaded waveguide helix slow-wave structure dispersion characteristics interaction impedance plasma filled computer simulation rib-loaded hybrid mode

A Study on Helical Coordinate System and Helical Slow Wave Structure

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A Study on Helical Coordinate System and Helical Slow Wave S...