No abstract

Abstract

Metal–organic frameworks (MOFs) and graphene aerogels (GAs) are both considered as good candidates for high‐performance supercapacitors. In this work, a growth‐oriented Fe‐based MOF synergized with GA composite for supercapacitor is prepared. MIL‐88‐Fe is in situ grown at (002) lattice plane on the surface of graphene via a one‐step solvothermal method. Long periodic hexagonal structure and electrophilicity of MOF provide strong p–π interaction with graphene sheets. By utilizing the abundant interspace of GA, the existence of MOF could affect the electric double‐layer characteristics of composites. The MOF/GA composites have the advantages of high capacitive volume, fast charge/discharge rate, and reliable cycling stability. The specific capacitance is as high as 353 F g−1 at the scan rate of 20 A g−1, and the retention ratio is 74.4% after 10 000 cycles.

No abstract

Spectroscopic properties of as-grown and gamma-irradiated undoped and Bi-doped alpha-BBO (BaB(2)O(4)) single crystals were investigated. Bi(2+) and color centers in Bi:alpha-BBO crystals were investigated to be nonluminescent in the near-infrared (NIR) region. Broadband NIR luminescence at 1139 nm with a FWHM of 108 nm and a decay time of 526 mus was realized in Bi:alpha-BBO crystal through gamma irradiation. Bi(+) was attributed to be responsible for the NIR emission, which can be bleached by thermal annealing. The involved physical processes in Bi:alpha-BBO crystal during the courses of irradiation and heat annealing were tentatively established.

Before shaping, Lu 2 O 3 powders doped with different ZrO 2 concentrations were synthesized by a simple combustion method and milled. The shaped green bodies were sintered at 1850°C for 6 h in vacuum. The transmittance and microstructure of the resultant ceramics were characterized by spectrophotometer and SEM. The effects of ZrO 2 concentration on the microstructure and optical property of transparent Lu 2 O 3 ceramics were evaluated. When doped with 5 at.% ZrO 2 , the Lu 2 O 3 ceramic showed the best optical transmission and the in-line transmittance reached 70% in the visible spectral region. The addition of ZrO 2 was found effectively to prohibit grain growth and to remove residual pores.

The crystallization, melting behavior, and spherulitic growth kinetics of biodegradable poly(ethylene succinate-co-6 mol % butylene succinate) [P(ES-co-6 mol % BS)] were investigated and compared with those of the homopolymer poly(ethylene succinate) (PES) in this work. The crystal structure of P(ES-co-6 mol % BS) was the same as that of neat PES, but the crystallinity decreased slightly because of the incorporation of the butylene succinate content. The glass-transition temperature decreased slightly for P(ES-co-6 mol % BS) compared to that for neat PES. The melting point of P(ES-co-6 mol % BS) decreased apparently; moreover, the equilibrium melting point was also reduced. Two melting endotherms were found for P(ES-co-6 mol % BS) after isothermal crystallization; this was ascribed to the melting, recrystallization, and remelting mechanism. The spherulitic growth rate of P(ES-co-6 mol % BS) was slower than that of neat PES at a given crystallization temperature. Both neat PES and P(ES-co-6 mol % BS) exhibited a crystallization regime II to III transition; moreover, the crystallization regime transition temperature of P(ES-co-6 mol % BS) shifted to a low temperature compared with that of neat PES.

No abstract