Composites with excellent thermomechanical and thermochemical properties are urgently needed in the aerospace field, especially for structural applications under high-temperature conditions. Carbon fiber-reinforced Si-based composites are considered the most promising potential high-temperature materials due to their excellent oxidation resistance and ablative behaviors, good structural designability, and excellent mechanical properties. The reinforcement of the relevant composites mainly involves carbon fiber, which possesses good mechanical and temperature resistance abilities. In this paper, the ablation behaviors and mechanisms of related composites are reviewed. For carbon fiber-reinforced pure Si-based composites (C/SiM composites), the anti-ablation mechanism is mainly attributed to the continuous glassy SiO₂, which inhibits the damage of the substrate. For C/SiM composite doping with refractory metal compounds, the oxides of Si and refractory metal together protect the main substrate from ablation and oxidation. Moreover, in addition to thermochemical damage, thermophysical and thermomechanical behavior severely destroy the surface coating of the substrate.

Previous papers about electrospun carbon nanofibers do not provide systemic understandings about how in situ activation agents affect the porous structure of carbon nanofibers. In this study, poly(vinylpyrrolidone), poly(methyl methacrylate), and high‐amylose starch (HAS) are used as activation agent to separately prepare porous carbon nanofibers from electrospun polyacrylonitrile nanofibers, and the effects of the polymer activation agents on the porous structure and supercapacitive properties of the resulting carbon nanofibers are examined. The studies indicate that melting point and decomposition temperature are two important parameters deciding the pore size profile. The one with high melting point and low decomposition temperature, such as HAS, allows to form micropore‐dominant porous structure with large specific surface area. The HAS‐activated carbon nanofibers have a micropore specific surface area as high as ≈809 m² g⁻¹, total pore volume of ≈0.42 cm³ g⁻¹, and micropore content as high as ≈59%. The corresponding electrodes have a capacitance of 282 F g⁻¹ at the current density of 1.0 A g⁻¹ with excellent cycling durability. These novel understandings may be useful for the development of effective carbon nanofibers for high‐performance supercapacitor and other applications.

Porous carbon nanofibers (PCNFs) with excellent physical and chemical properties have been considered candidate materials for electrodes used in supercapacitors. Herein, we report a facile procedure to fabricate PCNFs through electrospinning blended polymers into nanofibers followed by pre-oxidation and carbonization. Polysulfone (PSF), high amylose starch (HAS), and phenolic resin (PR) are used as three different kinds of template pore-forming agents. The effects of pore-forming agents on the structure and properties of PCNFs have been systematically studied. The surface morphology, chemical components, graphitized crystallization, and pore characteristics of PCNFs are analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and nitrogen adsorption and desorption test, respectively. The pore-forming mechanism of PCNFs is analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Fabricated PCNF-R have a specific surface area as high as ~994 m²/g, a total pore volume as high as ~0.75 cm³/g, and a good graphitization degree. When PCNF-R are used as active materials to fabricate into electrodes, the PCNF-R electrodes show a high specific capacitance ~350 F/g, a good rate capability ~72.6%, a low internal resistance ~0.55 Ω, and an excellent cycling stability ~100% after 10,000 charging and discharging cycles. The design of low-cost PCNFs is expected to be widely applicable for the development of high-performance electrodes for an energy storage field.

Sciatic nerve injury is commonly seen in clinical practice predominantly associated with trauma or sports injuries. Recent studies indicated that ginsenoside Rg1 (Gs Rg1), extracted from Chinese herbs, was found to promote regeneration of injured rat sciatic nerve and that nerve growth factor (NGF) may be involved in this process. The aim of this study was to examine the role that NGF may play in ginsenoside Rg1-induced regeneration of rat sciatic nerve following injury. Animals following surgical right sciatic nerve injury were subsequently administered intraperitoneally either saline (sham control) or different doses of 2, 4, 8, or 12 mg/kg daily GsRg1 for 2 to 8 wk. In addition, 100 μg/kg mecobalamin, a drug utilized to treat nerve injuries, was employed as a positive control. After 2, 4, or 8 wk, sciatic functional index (SFI) and mean nerve conduction velocity (MNCV), markers of sciatic nerve function, were assessed to determine whether recovery of injured sciatic nerve occurred. In addition, immunohistochemistry and Western blot methods were used to examine NGF protein expression changes. Results showed that all doses of GsRg1 significantly increased SFI and MNCV in injured sciatic-nerve-damaged rats in a manner similar to that noted with mecobalamin. It is of interest that the intermediate 4- and 8-mg/kg doses were more effective in restoring nerve functions. Immunohistochemistry and Western blot results also demonstrated a similar pattern with enhanced NGF protein expression at all doses, but greater effects were noted at 4 and 8 mg/kg GsRg1. Data suggest that GsRg1 promotes recovery of injured sciatic nerve functions within a specific dose range and that NGF may be involved in this physiological process.