Abstract Since the initial introduction of porous C 2 N‐h2D materials by the Baek group in 2015, these materials have exhibited highly promising applications in fields such as semiconductor devices, heterogeneous catalysis, gas storage and separation, biomedicine, and more. However, much of the existing research on C 2 N materials has been based on theoretical calculations due to the challenges associated with their synthesis. In this study, an enhanced synthesis method for porous C 2 N materials has been successfully developed, involving the innovative and nonexplosive synthesis of hexaaminobenzene trihydrochloride (HAB·3HCl) as a crucial intermediate, as well as a time‐efficient synthesis of C 2 N. Rigorous structural characterizations have been conducted, including solid‐state NMR analysis, among others. The resultant C 2 N material has been effectively employed to improve the efficiency of CO 2 conversion reactions. This straightforward protocol for synthesizing C 2 N materials is poised to stimulate further exploration and application of this promising 2D material in the near future.
Acoustic metamaterials have shown great potential for a number of acoustic applications due to their extraordinary, tunable acoustic properties such as deep sub-wavelength sound absorption, bandgaps, and focusing to name a few.Likewise, multiscale sorptive porous media have been shown to exhibit remarkable acoustic properties, including unusually high low frequency sound absorption and enabling the enhancement of the compliance of resonator's cavities or loudspeaker's boxes.This work applies labyrinthine metamaterials and multiscale sorptive porous materials to the design of vented-box loudspeakers.An electro-mechano-acoustical model of a ventedbox loudspeaker is introduced.This model takes into account the effects of the said meta-and porous material on the vented-box loudspeaker's sensitivity and electrical impedance.It is shown that by combining both types of materials, the form factor of vented-box loudspeakers can be significantly reduced, without compromising their low frequency performance.Thus, this work contributes towards the sought-after 'holy grail' of loudspeaker's design; that is to achieve 'big bass from small boxes'.
N,N′,N″-tripivaloyl-1,3,5-triaminobenzene (XT386) has been proven to be a highly efficient nucleating agent (NA) for polypropylene (PP), though it remains relatively expensive, which hinders its broader adoption. Herein, a methyl addition to benzene and a side-chain engineering strategy on XT386 led to the discovery of N,N′,N″-triacetyl-1,3,5-triaminotoluene (1a) as a very efficient NA for PP. It could raise the crystallization temperature (Tc) of iPP by 10.0 °C at a content not exceeding 1 wt %, reduce haze by 12.3, and increase tensile strength by 4.9 MPa. Refinement of PXRD data revealed that 1a has a c-axis size (∼6.5 Å) similar to PP, which has the ability to form epitaxial matching. Considering that 1a could be made from retired 2,4,6-trinitrotoluene (TNT) by a simple and green procedure of hydrogenation followed by N,N′,N″-triacylation, it will be a very promising NA for PP with good cost performance in the near future.
A crystallized Si2Sb2Te5 thin film was observed to extrude single-crystalline [0001] oriented tellurium nanowires at room temperature. The single crystalline Te nanowires nucleation and extruded outgrowth can be greatly accelerated by electron-beam-illumination (EBI) in a transmission electron microscope by an order as high as four. The EBI-enhanced outgrowth speed of Te nanowires is a function of electron beam flux and can be described as v=k ln(J+m). This Te nanowires self-outflow phenomenon comes from a decomposition process of the Si2Sb2Te5 matrix and provides an interesting model and mechanism of the nanowires’ growth, which is distinctive to the vapor-liquid-solid (VLS) mechanism.
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