In recent years, metamaterials have gained considerable attention as a promising material
technology due to their unique properties and customizable design, distinguishing them …

We report a methodology to reach the symmetrical broadband coherent perfect absorption in
an air tube whose reliability and feasibility are demonstrated experimentally. Through …

A noise with multiple tonal components is prevalent in practice, and these tones, contributing
to noise annoyance, may even span several octaves and the frequencies of them always …

A stepped-type multi-cavity combined sound absorber (SMCSA) was developed to improve
the low and mid-frequency sound absorption capabilities of micro-perforated panels. The …

Hybrid membrane resonator (HMR) as a typical metamaterial-based absorber with acoustic
hard boundary condition (AHBC) has demonstrated excellent noise absorption abilities, but …

Passive acoustic treatments are among the most widely adopted and effective solutions for
addressing various noise-control challenges. One important aspect of this scientific field lies …

In the present paper, a system composed of a two-port waveguide and two quarter
wavelength tubes (QWTs) with different cross section sizes is proposed. The narrow tube …

By coupling unstable components, we demonstrate a novel approach that reduces static
modulus to zero, eliminating causality-imposed absorption limitations in acoustics. Our …

We investigate fundamental constraints on passive linear time-invariant acoustic systems
through the developing alternative linear sum rules for sound absorption and transmission …

The method of Herglotz-Nevanlinna function is applied to derive sum rules in the one-
dimensional (1D) acoustic transmission problem with flow, in which a waveguide is lined by …