Highly Thermally Conductive and Structurally Ultra‑Stable Graphitic Films with Seamless Heterointerfaces for Extreme Thermal Management

Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics.

Effect of suction process on the growth of a convective gas bubble in diver's tissues

The motivation of this research is to study the effect of suction process on a growing gas bubble and concentration distribution around this bubble in tissues of divers who surface too quickly.The effect of bubble motion is also considered.The method of combined variables is used to solve the problem by combining the radial and time variables into one variable by using a suitable similarity transformation that enables to divide the diffusion equation into two ODEs,the first concerns to concentration distribution and the other concerns to the bubble radius evolution.The resultant formulae are valid for both growth stages whenever the ambient pressure is variable at ascending of the diver,or constant as the diving stops or at sea-level.The effects of physical parameters are discussed when applying suction process and show that the dominant parameter is the initial void fraction.The research findings reveal the role of suction process to activate the systemic blood circulation and delay the growth of gas bubbles in the tissues and reduce the incidence of decompression illness(DCI).This research also provides evidenceand agrees with the previous experimental studies to support the use of suction therapy to reduce the DCI harmful effects.

Oxygen quenching in a LAB based liquid scintillator and the nitrogen bubbling model

The oxygen quenching effect in a Linear Alkl Benzene （LAB） based liquid scintillator （LAB as the solvent, 3 g/L 2, 5 diphe-nyloxazole （PPO） as the fluor and 15 mg/L p-bis-（o-methylstyryl）-benzene （bis-MSB） as the h-shifter） is studied by measuring the light yield as a function of the nitrogen bubbling time. It is shown that the light yield of the fully purged liquid scintillator is increased by 11% at room temperature and the room atmospheric pressure. A simple nitrogen bubbling model is proposed to describe the relationship between the relative light yield （oxygen quenching factor） and the bubbling time.