Fatigue-resistant polyimide aerogels with hierarchical cellular structure for broadband frequency sound absorption and thermal insulation

Interface Optimizing Core–Shell PZT@Carbon/Polyurethane Composites with Enhanced Passive Piezoelectric Vibration Damping Performance

“…TL is defined as T L = L normalw normali − L normalw normalt = 10 .25em lg nobreak0em0.25em⁡ w normali w normalt in which L wi and L wt refer to the acoustic power level of incidence and transmittance while correspondingly w i and w t are acoustic power of incident and exit place . According to sound propagation through different media models, the incident sound would convert into three kinds of wave: reflective wave, absorptive wave, , and transmitted wave . TL is closely related to the reflective and absorptive waves, in which absorptive sound energy is related to the porosity and damping ability of materials and the surface density of materials determines reflective sound energy.…”

MXene@c-MWCNT Adhesive Silica Nanofiber Membranes Enhancing Electromagnetic Interference Shielding and Thermal Insulation Performance in Extreme Environments

“…Conventional thermal insulation materials are mainly divided into foam-based materials [5], phase change materials [6] and ceramic aerogel materials [7]. Among them, foam-based thermal insulation materials have defects such as low ignition point and release of toxic substances during combustion.…”

Metallization of Polyamide-imide for High-Frequency Communication by Polyethylenimine Modification and Electroless Copper Plating

“…With the rapid progression of 5G communication technology, information processing has progressively advanced into the domain of high-frequency communication electronics and high-speed data transmission. − As the foundation of high-frequency communication, dielectric filters have garnered increasing attention toward cost-effective and range-massive communication electronics in the past few years. , Among the various types of dielectric filter substrates, polyamide-imide (PAI) substrates have been widely utilized in fields including radar reconnaissance, field communication, and communication base station, with advantages of smaller volume, lighter weight, better temperature adaptability, etc. − Up to now, various techniques such as burning infiltration silver, sputtering, and coating have been extensively investigated for the fabrication of conductive layers on PAI substrates. − Nevertheless, the high-temperature aging process of silver paste is time-consuming and energy-intensive. Meanwhile, the conventional sputtering process necessitates high-vacuum and voltage, which results in significant energy consumption. − Furthermore, the metallized PAI substrate prepared through coating typically results in a thick layer of copper, which cannot meet the requirements for ultrathin layers. − To achieve the metallization of substrates with superior adhesion, prospective metal thickness, and optimal cost-effectiveness, extensive research has been conducted on the process of electroless copper plating (ECP) onto the modified substrate surface. − As a well-established autocatalytic technique, electroless deposition is extensively utilized for the production of high-adhesion and low-resistivity metal layers on various types of materials, including polymer plastics, − papers, , ceramics, − and glasses. − Nevertheless, achieving strong adhesion between autocatalytic sites and smooth surfaces of PAI substrates without combinative functional groups or mechanical bonding points is full of challenges. −…”