scholarly journals Magnetoactive acoustic metamaterials based on nanoparticle-enhanced diaphragm

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xingwei Tang ◽  
Shanjun Liang ◽  
Yusheng Jiang ◽  
Cong Gao ◽  
Yujin Huang ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Effective Mass ◽  
Magnetic Force ◽  
Mass Density ◽  
Second Derivative ◽  
Acoustic Metamaterials ◽  
Vibration Properties ◽  
Potential Applications ◽  
Membrane Type ◽  
The Magnetic Field

AbstractMagnetoactive membrane-type acoustic metamaterials are fabricated by coating a layer of magnetic nanoparticles on the polyethylene (PE) membranes and their vibration characters are investigated experimentally. From our experiments, we discovered that, under different magnetic fields by varying the distance between a magnet and the membranes, such membranes exhibit tunable vibration eigenfrequencies (the shift towards lower frequencies), which is caused by the variation of the effective mass density and effective tension coefficient resulted from the second derivative of the magnetic field. The strong magnetic force between the layer of magnetic nanoparticles and the magnet enhances the eigenfrequency shift. A spring oscillator model is proposed and it agrees well with the experimental results. We also experimentally observed that the vibration radius, effective mass density, and effective tension coefficient of the membranes can enormously affect the eigenfrequencies of the membranes. We believe that this type of metamaterials may open up some potential applications for acoustic devices with turntable vibration properties.

scholarly journals Investigation on the Band Gap and Negative Properties of Concentric Ring Acoustic Metamaterial

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Meng Chen ◽  
Dan Meng ◽  
Heng Jiang ◽  
Yuren Wang
Keyword(s):  
Band Gap ◽  
Effective Mass ◽  
Coupling Effect ◽  
Mass Density ◽  
Band Gaps ◽  
Acoustic Metamaterials ◽  
Concentric Ring ◽  
Resonance Modes ◽  
Negative Effective Mass ◽  
Single Oscillator

The acoustic characteristics of 2D single-oscillator, dual-oscillator, and triple-oscillator acoustic metamaterials were investigated based on concentric ring structures using the finite element method. For the single-oscillator, dual-oscillator, and triple-oscillator models investigated here, the dipolar resonances of the scatterer always induce negative effective mass density, preventing waves from propagating in the structure, thus forming the band gap. As the number of oscillators increases, relative movements between the oscillators generate coupling effect; this increases the number of dipolar resonance modes, causes negative effective mass density in more frequency ranges, and increases the number of band gaps. It can be seen that the number of oscillators in the cell is closely related to the number of band gaps due to the coupling effect, when the filling rate is of a certain value.

Active acoustic metamaterials with tunable effective mass density by gradient magnetic fields

2014 ◽  
Vol 105 (7) ◽  
pp. 071913 ◽  
Author(s):  
Xing Chen ◽  
Xianchen Xu ◽  
Shigang Ai ◽  
HaoSen Chen ◽  
Yongmao Pei ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Effective Mass ◽  
Mass Density ◽  
Acoustic Metamaterials ◽  
Active Acoustic Metamaterials

Transmission Loss of Membrane-Type Acoustic Metamaterial with Negative Effective Mass

2017 ◽  
Vol 898 ◽  
pp. 1749-1756 ◽  
Author(s):  
Guo Chang Lin ◽  
Song Qiao Chen ◽  
Yu Liang Li ◽  
Hui Feng Tan
Keyword(s):  
Effective Mass ◽  
Transmission Loss ◽  
Mass Density ◽  
Small Mass ◽  
Equivalent Model ◽  
Sound Insulation ◽  
Rubber Membrane ◽  
Acoustic Metamaterial ◽  
Spring Force ◽  
Membrane Type

The transmission loss (TL) of membrane-type acoustic metamaterials consisting of small mass and rubber membrane was studied. By establishing a mass-spring equivalent model of metamaterial structural unit, which regards rubber membrane as having the dual role of damping force and spring force, we demonstrated that effective mass density of this membrane-type acoustic metamaterial was negative in the band gap range by theoretical analysis. Based on the theory of plane wave propagation, we studied the sound insulation of this membrane-type acoustic metamaterial. The result showed that membrane-type metamaterial was based on the principle of dipole resonance, which made the membrane-type acoustic metamaterial appear high reflection and low transmission phenomenon so as to achieve the aim of reducing noise. By optimal design, the sound attenuation frequency range of this membrane-type acoustic metamaterial was reduced to 20Hz-100Hz, greatly enhancing the ability of this metamaterial in terms of low-frequency sound insulation. We obtained the distribution of sound intensity at the optimum transmission frequency and the best reflection frequency by coupled acoustic-structural analysis. The best sound insulation frequency was matched with the second order and the third order eigenfrequency of this membrane-type acoustic metamaterial unit, and the strain energy was concentrated at the joint of small mass and the membrane. The total sound insulation of acoustic metamaterial plate was better than the single metamaterial unit.

Guiding the Nonmagnetic Particles by Magnetic Nanoparticles in a Microfluidic Device Using External Magnetic Fields

2009 ◽  
Author(s):  
R. Asmatulu ◽  
B. Zhang ◽  
N. Nuraje
Keyword(s):  
Magnetic Nanoparticles ◽  
Microfluidic Device ◽  
Magnetic Force ◽  
Power Level ◽  
Field Testing ◽  
Microfluidic System ◽  
Efficient Separation ◽  
Micro Channels ◽  
Nonmagnetic Particles ◽  
The Magnetic Field

A microfluidic device was fabricated via UV lithography technique to separate nonmagnetic fluoresbrite carboxy microspheres (∼4.5 μm) from the ferrofluids made of magnetic nanoparticles (∼10 nm). A mixture of microspheres and ferrofluid was injected to lithographically developed Y shape micro channels, and then by applying the external magnet field, the fluoresbrite carboxy microspheres and ferrofluids were clearly separated into different channels because of the magnetic force acting on those nonmagnetic particles. During the fabrication, a number of different parameters, such as UV exposure times, UV power level and photoresist thickness were tested to optimize for our needs. In addition, in the magnetic field testing, different pumping speeds, and particle concentrations associated with the various distances between the magnet and the microfluidic system were studied for an efficient separation.

scholarly journals Scaffold-free, Label-free, and Nozzle-free Magnetic Levitational Bioassembler for Rapid Formative Biofabrication of 3D Tissues and Organs

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Vladislav A. Parfenov ◽  
Stanislav V. Petrov ◽  
Frederico D. A. S. Pereira ◽  
Aleksandr A. Levin ◽  
Elizaveta V. Koudan ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Magnetic Nanoparticles ◽  
Magnetic Force ◽  
Short Review ◽  
Label Free ◽  
Conceptual Foundation ◽  
The Past ◽  
Potential Applications ◽  
Engineering Strategy ◽  
Potential Alternative

Scaffolding is the conceptual framework of conventional tissue engineering. Over the past decade, scaffold-free approaches as a potential alternative to classic scaffold-based methods have emerged, and scaffold-free magnetic levitational tissue engineering (magnetic force-based tissue engineering [Mag-TE]) is a type of this novel tissue engineering strategy. However, Mag-TE is often based on the use of potentially toxic magnetic nanoparticles. Scaffold-free and label-free magnetic levitational bioassembly do not employ magnetic nanoparticles and thus, the potential toxicity of magnetic nanoparticles can be avoided. In this short review, we describe the conceptual foundation of scaffold-free, label-free, and nozzle-free formative biofabrication using magnetic fields as “scaffields.” The design and implementation of “Organ.Aut,” the first commercial magnetic levitational bioassembler, and the potential applications of magnetic bioassembler are discussed as well.

Study of MFM Application in Semiconductor Failure Analysis

2004 ◽  
Author(s):  
Way-Jam Chen ◽  
Lily Shiau ◽  
Ming-Ching Huang ◽  
Chia-Hsing Chao
Keyword(s):  
Magnetic Field ◽  
Failure Analysis ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Current Flow ◽  
Force Microscopy ◽  
The Magnetic Field ◽  
A Current

Abstract In this study we have investigated the magnetic field associated with a current flowing in a circuit using Magnetic Force Microscopy (MFM). The technique is able to identify the magnetic field associated with a current flow and has potential for failure analysis.

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