High-performance thermal interface materials enabled by vertical alignment of lightweight and soft graphene foams

High-performance thermal interface materials (TIMs) are highly sought after for modern electronics. Two-dimensional (2D) materials as vertical aligned fillers can optimize the out-plane thermal conductivity (k ⊥), but their excessively high content or intrinsic rigidness deteriorate TIMs softness, leading to worsening for thermal contact resistance (R contact). In this study, 2D graphene materials are fabricated into lightweight and soft graphene foams (GFs) with high-orientation, acting as vertical filler frameworks to optimize the k ⊥ and R contact for vertical GF (VGF) TIMs. The VGF-TIM has a high k ⊥ of 47.9 W·m^(−1)·K^(−1) at a low graphene content of 15.5 wt.%. Due to the softness and low filler contents of GFs, the VGF-TIM exhibits a low compressive module (4.2 MPa), demonstrating excellent compressibility. The resulting TIM exhibit a low contact resistance of 24.4 K·mm2·W^(−1), demonstrating 185.1% higher cooling efficiency in practical heat dissipating scenario compared to commercial advanced TIMs. This work provides guidelines for the design of advanced TIMs and their applications in thermal management.

Three-Wave Mixing of Dipole Solitons in One-Dimensional Quasi-Phase-Matched Nonlinear Crystals

A quasi-phase-matched technique is introduced for soliton transmission in a quadratic[χ^((2))]nonlinear crystal to realize the stable transmission of dipole solitons in a one-dimensional space under three-wave mixing.We report four types of solitons as dipole solitons with distances between their bimodal peaks that can be laid out in different stripes.We study three cases of these solitons:spaced three stripes apart,one stripe apart,and confined to the same stripe.For the case of three stripes apart,all four types have stable results,but for the case of one stripe apart,stable solutions can only be found atω_(1)=ω_(2),and for the condition of dipole solitons confined to one stripe,stable solutions exist only for Type1 and Type3 atω_(1)=ω_(2).The stability of the soliton solution is solved and verified using the imaginary time propagation method and real-time transfer propagation,and soliton solutions are shown to exist in the multistability case.In addition,the relations of the transportation characteristics of the dipole soliton and the modulation parameters are numerically investigated.Finally,possible approaches for the experimental realization of the solitons are outlined.

Safety assessment of monosodium glutamate based on intestinal function and flora in mice

Although monosodium glutamate(MSG)is a widely used food additive,its safety and systemic side effects have not been fully clarified.The intestinal flora is closely associated with human health;however,it remains unclear whether MSG consumption can affect health by acting on the intestinal flora.In this study,serum biomarkers,intestinal structure,intestinal immunity,and intestinal flora were examined to investigate the effects of different doses of sodium glutamate on the body,intestinal function,and intestinal flora of mice.The results showed that 30 mg/kg MSG had no significant effect on serum C-reactive protein,trimethylamine N-oxide,angiotensin II,intestinal interleukin(IL)-1β,IL-6,tumor necrosis factor-α,secretory IgA and fecal albumin in mice,but also promoted intestinal development and regulated the intestinal flora.Moreover,1500 mg/kg MSG increased the risk of cardiovascular disease and damaged the intestinal structure and flora.In this study,MSG was also found to be healthier than salt at the equivalent sodium concentration.Collectively,these findings suggested that low doses of MSG were safe for mice and may have some health benefits as a probiotic by promoting intestinal development and regulating the intestinal flora.