Thermal management materials are solutions to heat dissipation issues in electronic devices, which are key to the device reliability and lifetime. Epoxy-based materials have been widely used but suffer from their intrinsically low thermal conductivity. In this work, we employ the combined hydrothermal reduction, ice-templated assembly, and vacuum-assisted infiltration methods to construct well-aligned rigid three-dimensional (3D) networks of reduced graphene oxide (RGO) walls bridged by (functional) single wall carbon nanotubes ((f)SWCNTs) in the epoxy resin. The 3D RGO/(f)SWCNT aerogel notably enhances thermal conductivity, reduces the coefficient of thermal expansion (CTE), and increases the glass-transition temperature (T g ) without deteriorating the electrical insulating property. Remarkably, the (RGO/fSWCNT) 1:2.5 epoxy nanocomposite reaches a thermal conductivity of 0.63 to 0.69 W m −1 K −1 from 300 to 390 K at a very low filler loading of 3.65 vol %, which is more than four times enhancement over the pure epoxy resin. The CTE decreases by 11.2 ppm K −1 and T g increases by 20 K. We also show that the functional groups associated with the 3D RGO/fSWCNT aerogel are beneficial for improvement in thermal conductivity, dimensional stability, and thermal stability. The epoxy nanocomposites reported by this work demonstrate strong potential for thermal management application in electronic packaging.

Cu2S compounds are promising thermoelectric (TE) candidate materials with environmentally friendly and earth abundant chemical constituents. A series of phase transitions occur with temperature whereas only the high temperature stabilized cubic structure (α‐Cu2S) exhibits desirable TE properties. In this work, by alloying Cu sites with Mn, Zn, Ga, and Ge, profound influence on β‐ to α‐Cu2S phase transition and thermoelectric transport properties is observed. Both phase transition temperature (Tc) and the enthalpy of phase change (ΔH) decreases with doping; remarkably, for Cu1.95Mn0.03S, Tc reduces by ≈156 K. The Seebeck anomaly near the critical point of phase transition also vanishes. The electrical conductivity is remarkably improved for doped samples due to the largely elevated hole concentration. In comparison with pristine Cu2S, not only is the peak TE power factor substantially enhanced (by ≈272%), but also the average ZT for 500–823 K is highly improved (by ≈145%) due to the successful stabilization of α‐Cu2S at lower temperatures. The present work offers a clue to enlarge the temperature regime of high TE properties, which is practically useful for a variety of polymorphous thermoelectric compounds.

The orientation-dependent physical transport properties of ZnO nanocomposites induced by intrinsic anisotropy of SWCNT/graphene and ZnO/carbon interfaces.

α-Ag2S is a ductile inorganic semiconductor recently identified, which can undergo considerable plastic deformation without the aid of dislocations. Together with its intrinsically poor electrical conductivity, it is one ideal system to study the effect of plastic deformation on phonon thermal transport. In this work, we show that the room temperature phonon thermal conductivity of α-Ag2S monotonically increases with compressive strain by about 32% at a compressive strain of 0.7. No deformation-induced phase transition occurs. Electrical conductivity and the Seebeck coefficient are basically invariant with deformation. No transport anisotropy is observed between the directions that are parallel and perpendicular to the compression direction. The stored energy in α-Ag2S measured by differential scanning calorimetry increases with strain but is remarkably larger than plastically deformed Cu at large strains. Possible origins for the increasing phonon thermal conductivity with plastic deformation are discussed. The present work provides original experimental observations on the effect of plastic deformation on phonon thermal conductivity, and it has important implications for the development of α-Ag2S-based ductile thermoelectric semiconductors and devices.

The present study aimed to investigate the use of computerized tomography (CT) perfusion for evaluating cerebral hemodynamics following traumatic brain injury (TBI) in rabbits. The animals were randomly assigned into four groups (n=10 animals/group): i) Control, ii) TBI, iii) TBI + common decompression and iv) TBI + controlled decompression groups. A TBI model was established in rabbits using epidural balloon inflation. In the groups receiving intervention, animals were provided common decompression or controlled decompression treatments. Conventional CT and CT perfusion scanning were performed, with cerebral hemodynamic indices, including regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and mean transit time (MTT) being measured. Blood-brain barrier (BBB) permeability was evaluated using Evans blue staining. Compared with those in the control group, rCBF and rCBV values of the bilateral temporal lobes and basal ganglion in the TBI, TBI + common decompression and TBI + controlled decompression groups were significantly lower, whereas the MTT values were markedly prolonged and Evans blue dye content was greatly increased (P<0.01). Controlled decompression was demonstrated to be more potent than common decompression for preventing TBI-induced decline in rCBF and rCBV values in the bilateral temporal lobes and basal ganglion, as well as reversing TBI-induced extension of MTT in the bilateral temporal lobes (P<0.01 vs. TBI group). However, neither common nor controlled decompression could reduce TBI-induced increase in BBB permeability. In conclusion, these findings indicate that CT perfusion may be used to monitor cerebral hemodynamics following TBI in rabbits. Controlled decompression was deduced to be more potent than common decompression for preventing abnormalities in cerebral hemodynamics after TBI.