Results 71 to 80 of about 1,130 (256)

Unveiling the structure-property relationships of multilayered Helmholtz resonance-based acoustic metamaterials

Smart Materials in Manufacturing
The principle of Helmholtz resonance has been widely employed in the design of sound-absorbing metamaterials. However, the relationship between various acoustic parameters and sound absorption performance remains insufficiently understood.
Jun Wei Chua, David Kar Wei Poh, Shuwei Ding, Haoran Pei, Xinwei Li   +4 more
doaj   +1 more source

Acoustical performance of Helmholtz resonators used as vehicular silencers [PDF]

FME Transactions, 2018
This study proposes to evaluate the acoustical performance of a reactive vehicular silencer made entirely of Helmholtz resonator. Four or seven resonators are idealized to be in a series configuration, all the dimensions except cavity length and ...
Martins Lucas Rodrigues, Guimarães Gustavo Paulinelli, Fragassa Cristiano   +2 more
doaj  

Photoelectric Imaging of the Optically Inactive Charge State of Silicon‐Vacancy Defects in Diamond

Advanced Science, EarlyView.
Although the doubly negative charge state of the SiV center in diamond is predicted to ionize only in the ultraviolet and is therefore considered optically inaccessible, we demonstrate visible‐range photoelectric imaging enabled by a previously unrecognized regime of laser‐assisted tunneling. ABSTRACT The investigation of optically active point defects
Ilia Chuprina, Gergő Thiering, Emilie Bourgeois, Anna Ermakova, Dmitry Budker, Adam Gali, Milos Nesladek, Petr Siyushev, Fedor Jelezko   +8 more
wiley   +1 more source

High‐Entropy Engineering and External Magnetic Field Modulation Synergistically Enhance the H2S Sensing Performance of Rare‐Earth Perovskite Ferrites

Advanced Science, EarlyView.
A novel high‐entropy perovskite oxide, (Gd0.2Tb0.2Dy0.2Ho0.2Er0.2)FeO3, was successfully synthesized for advanced hydrogen sulfide gas detection. By synergistically coupling high‐entropy‐induced local lattice distortion with weak magnetic field modulation, the tailored material generates abundant active sites. This innovative dual strategy dramatically
Yunfei Wang, Min Zhang, Rui Li, Xiaolong Yao, Zhaofeng Wu, Fengdong Qu, Shan Qiu, Zhenjiang Li   +7 more
wiley   +1 more source

Theoretical research on the application of impedance calculation in the design of high-intensity low-frequency acoustic generator

Journal of Low Frequency Noise, Vibration and Active Control
The impedance matching is essential in producing high-intensity acoustic waves. This paper studies the impedance calculation methods of modulators and double-chamber Helmholtz resonators based on fluid mechanics, aeroacoustics, and electro-acoustic ...
Baoguo Zhang, Mingrong Dong, Xubin Liang, Min Zhang, Tianqing Zhao, Bin He, Deyu Sun   +6 more
doaj   +1 more source

Experimental realization of extraordinary acoustic transmission using Helmholtz resonators

AIP Advances, 2015
The phenomenon of extraordinary acoustic transmission through a solid barrier with an embedded Helmholtz resonator (HR) is demonstrated. The Helmholtz resonator consists of an embedded cavity and two necks that protrude, one on each side of the barrier ...
Brian C. Crow, Jordan M. Cullen, William W. McKenzie, Vijay Koju, William M. Robertson   +4 more
doaj   +1 more source

Voltage‐Driven Non‐Volatile Interconversion Between Giant Single‐Domain and Multidomain Magnetic States in a Multiferroic Heterostructure

Advanced Science, EarlyView.
Non‐volatile voltage control of magnetic configurations is achieved in a strain‐coupled multiferroic heterostructure. Voltage pulses reversibly interconvert giant single‐domain and multidomain magnetic states, which remain stable at zero applied voltage. ABSTRACT Voltage control of magnetic states in multiferroic heterostructures represents a promising
M. Ghidini, S. Valencia, A. Lesaine, R. Mansell, V. Farenkov, X. Moya, N. A. Stelmashenko, F. Maccherozzi, C. W. H. Barnes, F. Kronast, S. S. Dhesi, N. D. Mathur   +11 more
wiley   +1 more source

Compact Acoustic Rainbow Trapping in a Bioinspired Spiral Array of Graded Locally Resonant Metamaterials

Sensors, 2019
Acoustic rainbow trappers, based on frequency selective structures with graded geometries and/or properties, can filter mechanical waves spectrally and spatially to reduce noise and interference in receivers.
Liuxian Zhao, Shengxi Zhou
doaj   +1 more source

Noise attenuation capacity of a Helmholtz resonator

Advances in Engineering Software, 2018
The noise attenuation capacity of a HR defined as the integral of transmission loss in the frequency domain is first derived.The theoretical formula of noise attenuation capacity shows that it is only determined by the geometries of the neck and the cross-sectional area of the duct.The theoretical formula is validated by FEM simulation using COMSOL ...
Chenzhi Cai, Cheuk Ming Mak
openaire   +3 more sources

TiO6 as a Compensatory Structural Unit in Co‐Free, High‐Ni Layered Oxide for Durable Lithium‐Ion Batteries

Advanced Science, EarlyView.
Ti substitution stabilizes Co‐free high‐Ni layered oxides through both structural and electronic effects. TiO6 octahedra act as compensatory structural units that help interrupt cooperative Jahn–Teller distortion and suppress detrimental phase transitions, while the electron‐withdrawing inductive effect of Ti stabilizes the oxygen lattice. As a result,
Bixian Ying, Zhenjie Teng, Jun Wang, Honghong Tian, Charlotte von Petersdorff‐Campen, Rommel T. Tolla, Iuliia Mikulska, Linus Voigt, Sascha Nowak, Verena Naber, Alexander Schökel, Yuanming Liu, Michael Merz, Peter Nagel, Stefan Schuppler, Katja Frenzel, Adrian Jonas, Lena Mathies, Martin Winter, Karin Kleiner   +19 more
wiley   +1 more source