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In this paper, the friction and wear properties of 3D braided carbon fiber wet friction material at 2550r/min, 3800r/min and 5100r/min were studied with MM3000 friction and wear tester, and the wear mechanism was studied with SEM. The results show that the average static friction coefficient of friction materials is 0.153; With the increase of rotating speed, the dynamic friction coefficient decreases from 0.095 to 0.087; The volume wear rate decreased from 9.46*10−8cm3/J to 2.58*10−8cm3/J; The friction torque curves at three different speeds are relatively stable, showing the material has good braking stability. 3D braided carbon fiber friction material has fiber fracture and crack on the raised surface of the material after 1500 times of jointing at three different speeds. The mechanism of friction and wear is abrasive wear and fatigue wear.

Two-dimensional (2D) van der Waals (vdW) heterostructures have attracted much attention due to their unique properties in photocatalysis, electronics, and energy storage. This work comprehensively analyzed the electronic properties and photocatalytic efficiency properties of 2D vdW MoS2/Hf2CO2 heterostructure by first-principles calculations and molecular dynamics simulation. An ideal band gap of 1.44 eV was found for visible light absorption. Meanwhile, a high solar-to-hydrogen efficiency of 17.14% is obtained from the calculated band-edge positions, and a high power conversion efficiency of 13.84% is also confirmed by spectroscopy limited maximum efficiency simulation. We estimate the time scale for electron–hole transfer and recombination times using a combination of non-adiabatic molecular dynamics and time-dependent density functional theory. A suitable e-h recombination time of 1.86 ns and electron (hole) transfer time of 331 (978) fs are obtained in the 2D MoS2/Hf2CO2 heterostructure, which is expected to ensure high photocatalytic efficiency. Therefore, the constructed MoS2/Hf2CO2 heterostructures provide a new example for the prediction of high-performance nano optoelectronic devices.

This article uses powder metallurgy technology to prepare foamed aluminum and carbon nanotubes (CNTs) / foamed aluminum composites. The laser thermal diffusion analyzer, thermal analyzer, and transfer function sound absorption coefficient test system were used to study the thermal conductivity and sound absorption properties of aluminum foam and its composites, respectively. The results show that the thermal conductivity of aluminum foam with 79% porosity is only 5W · m−1·K−1, which is much smaller than the thermal conductivity of aluminum. So it can be used as an ideal thermal insulation material; The thermal conductivity of carbon nanotubes (CNTs) / foamed aluminum-based composites increases first and then decreases with the increase in the mass fraction of CNTs. As the test temperature increases, the thermal conductivity of the material gradually increases. When the mass fraction of CNTs is 0.75%, the thermal conductivity of foamed aluminum-based composites reaches the maximum. As the test frequency increases, the sound absorption performance of foamed aluminum first increases, then decreases, and then gradually increases, reaching a maximum value around 1000 Hz. The sound absorption performance of CNTs / foam aluminum matrix composites decreases at lower test frequencies as the mass fraction of CNTs increases. At higher frequencies, as the mass fraction of CNTs increases, the sound absorption coefficient of foamed aluminum decreases first and then increases.

This article uses powder metallurgy to prepare aluminum foam and carbon nanotubes (CNTs) / foam aluminum composites. The effects of the surface treatment of carbon nanotubes, the amount of pore-forming agent, and the amount of carbon nanotubes on the microstructure of aluminum foam and its composites were studied by means of infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy. The results show that the mixed acid treatment of CNTs can effectively disperse CNTs and introduce new functional groups on their surfaces. Using NH4HCO3 as a pore-forming agent and using powder metallurgy, a porosity of 41% to 79%, Cellular pure foam aluminum material and CNTs / foam aluminum matrix composite with 60% porosity.

A large area explosive emission cold cathode has been fabricated using carbon nanotube (CNT) emitters. The emission characteristics of the CNT cathode have been measured in two different pulse modes. A high emission current density of 344 A cm−2 has been realized at an applied electric field of 16.7 V µm−1 and the current density maintained at 160 A cm−2. The distribution and intensity of the electron beams on the cathode surface were investigated. The emission model of the cathode applied with pulse electric field was established and the pulsed emission mechanism of CNTs was explosive electron emission. Meanwhile, the formation of the cathode plasma layer was found. Such a cathode design can be expected to be utilized as a high-current, large area emitter.

Silver (Ag) nanowires with a pentagonal cross section have been synthesized by polyvinylpyrrolidone (PVP)-assisted polyol reduction in the presence of Pt nanoparticle seeds. The UV–visible absorption spectra and scanning electron microscopy have been used to trace the growth process of the Ag nanowires. X-ray photoelectron spectroscopy investigation further shows that the PVP molecules are adsorbed on the surface of the Ag nanowires through Ag : O coordination. Comparing with the growth process of Ag nanoparticles, a possible growth mechanism of the Ag nanowires has been proposed. It is implied that the PVP molecules are used as both a protecting agent and a structure-directing agent for the growth of Ag nanowires. It is concluded that the five-fold twinning Ag nanoparticles are formed through heterogenous nucleation after the introduction of Pt nanoparticle seeds and then grow anisotropically along the 110 direction, while the growth along 100 is relatively depressed.