叶菁华 , 朱铧丞 
微波辅助生物柴油生产越来越受到了人们的关注，但是，微波的不均匀加热也影响了微波辅助生物柴油的大规模生产。研究表明，连续流微波加热器可以有效地解决微波辅助生物柴油的批量生产问题，螺旋推进器也可以改善加热均匀性，于是仿真带有螺旋推进器的连续流微波加热器的生物柴油生产过程，有利于优化连续流微波加热器的设计，对提高微波辅助生物柴油生产效率有重要的意义。 本文使用了电磁场、旋转机械流、流体传热和化学反应接口。电磁场中的介电系数是关于温度和物质浓度的函数，流体的热参量由流体各组分的质量比等效所得。计算采用步进求解的方法，先在频域求解电磁场，所得的耗散功率代入流体传热，再将求解得到的温度和浓度用于更新介电系数，如此类推直至计算时间结束。 图1为有无螺旋推进器的连续流微波加热器的纵截面温度分布图，可见由于螺旋推进器的搅拌作用，流体的温度均匀性得到了很好的提高 ...
Self-Consistent Modeling of Thin Conducting Wires and Their Interaction with the Surrounding Electromagnetic Field
ABB AB, Corporate Research, Västerås, Sweden
It is demonstrated how the RF Module of COMSOL Multiphysics® can be used to approximately model thin conducting wires or cables and how they interact with a surrounding electromagnetic field. Despite being non-stringent the method can reasonably well predict currents induced by an applied electromagnetic field in wires, and networks of wires, as well as fields radiated from current-carrying ...
G. Rana , S. P. Duttagupta , P. Deshmukh , S. S. Prabhu ,
 Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
 Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
Ellipsometry has been the most efficient and accurate method for determining optical constants of a given material. In this article, we present a novel concept for designing an ellipsometer for Terahertz frequencies based on reflection geometry THz Time Domain Spectroscopy. The present ellipsometers for THz are either based on parabolic mirrors cavities or lens based cavities. The former one has ...
M. Awida ,
 Fermi National Particle Accelerator Laboratory, Warrenville, IL, USA
Particle accelerator technology evolves gradually towards improving reliability and efficiency of the accelerator machines, which would reduce their cost for current applications and even make them more accessible to new industrial applications. RF cavities are utilized in particle accelerator machines to propel the particle beam by properly coupling the energy from RF sources to the particle ...
J. L. Munoz, and I. Rodriguez
A proton linac drives particles using the electric field of a high power RF standing wave in a resonant cavity. The design of these cavities involve several aspects of multiphysics simulation, that have been accomplished using COMSOL. The first step consist on the geometric optimization of the cavities in order to have the correct frequency while maximizing some figures of merit. This task ...
Optimized Illumination Directions of Single-Photon Detectors Integrated with Different Plasmonic Structures
M. Csete, Á. Sipos, A. Szalai, G. Szabó
Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary
The optimal orientations of different single-photon detector designs were determined by COMSOL software package. Absorption of niobium-nitride (NbN) stripes in two different (p=220 nm, 3p=660 nm) periodic patterns integrated with plasmonic elements was studied. In OC-SNSPDs consisting of ~quarter-photon-wavelength nano-cavity the optimum direction is perpendicular incidence onto NbN stripes in P ...
M. G. Sridharan, A. Prabhakar, and S. Bhattacharya
Photonics Group, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, India
Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, India
Phase gratings are used in many applications owing to their high transmission and thus higher diffraction efficiencies. COMSOL is based on finite element modeling and is chosen for 2 reasons; firstly, because it can handle complex 2-D and 3-D geometries and secondly, it can handle the vector nature of these structures. The objective of the design is to compare the results of a commonly used ...
S. Musa, M. N. O. Sadiku
Prairie View A&M University, Prairie View, TX, USA
The microstrip line is widely used as the planar transmission line in microwave integrated circuits and high speed interconnecting buses. In this paper, we use COMSOL Multiphysics® to study multiconductor microstrip systems on microwave integrated circuits. We specifically illustrate the modeling of open four and five conductors systems. We successfully demonstrated the calculation of the ...
吴强 , 潘崇佩 , 张琦 ,
“极化激元”是固体物理学中的重要概念，泛指各种极性元激发与光子的耦合。其中，声子极化激元是指晶格振动的声子与电磁场中的光子相互耦合的一种极化激元波。使用飞秒光在铁电晶体铌酸锂中通过光学非线性效应可产生声子极化激元，其频率位于太赫兹波段，在晶格的振动弛豫、太赫兹光谱、与介观微结构作用等领域已有广泛应用。 声子极化激元涉及电磁场和晶格场的耦合问题，其形式满足黄昆方程。我们使用 COMSOL Multiphysics® 的多物理场（偏微分方程组以及射频模块）模拟了块状铌酸锂晶体中产生声子极化激元波的产生和传输。 铌酸锂晶体作为太赫兹应用的集成化平台，可通过在平板波导上引入微结构实现对太赫兹波的调控。诸多手段中，太赫兹天线作为电磁场的传播场与局域场转换的关键部件，对太赫兹通信和太赫兹光谱等领域都有不可替代的作用。基于这一点，我们设计了一种尖端相对的棒状天线结构，使用 COMSOL ...
Institute of Physics CAS
Chiral SPPs can be generated by linearly polarized light incident at the end of a nanowire, exciting a coherent superposition of three specific nanowire waveguide modes. Chirality is preserved in the emitted photons, creating a subwavelength ¼ wave plate.