煤-树脂混合物残炭的形貌分析

借助扫描电子显微镜研究了原煤及其各种树脂混合物经微型反应釜中350℃和400℃处理后所获残炭的形貌。结果表明：富氢煤的显微组分被分解，而丝炭和角质等煤的显微组分难分解。添加诸如高密、低密聚丙烯及聚苯乙烯等树脂后可加速煤的显微组分的分解，并改变了其残炭的显微形貌。     

Hydrogen production by methane decarbonization: Carbonaceous catalysts

Decarbonization of natural gas by thermo-catalytic decomposition, TCD, to produce hydrogen and carbon is a very attractive alternative to steam methane reforming (SMR) for small-to-medium size facilities because by TCD, the carbon contained in natural gas is collected as a solid, marketable product. In this paper, the use of different carbon blacks with a high external surface area, easily accessible to methane molecules has been explored as an alternative to activated carbons.     

CATALYST REGENERATION KINETICS VIA THERMOGRAVIMETRIC ANALYSIS

The regeneration of a commercial hydrotreating catalyst was investigated by means of a thermo-balance reactor. The kinetics of combustion of carbonaceous deposits were measured over a wide range of conditions. The rate controlling mechanism changed from the intrinsic chemical kinetics to pore diffusion as operating variables were changed. The thermogravimeiric method proved to be a quick and reliable means of measuring catalyst regeneration kinetics.     

Metal-catalyzed cross-coupling reactions with supported nanoparticles: Recent developments and future directions

The metal-catalyzed processes are ubiquitous in the modern organic synthesis toolbox. However, a continuous challenge has been related to the design of reactions from a sustainable viewpoint (e.g., easy recovery of the catalyst, ability to perform sequential steps in high yields, avoidance of high amounts of organic solvents). Supported nanocatalysts have prompted special interest because of the synergy involving eletronic and surface effects which can play key roles towards more sustainable processes. In this article, we comprehensively summarize the latest progress in cross-coupling reactions involving supported metal nanoparticles. A background to mechanisms and industrial application will also be presented.     

Fabrication of magnetic Fe3O4/C/TiO2 composites with nanotube structure and enhanced photocatalytic activity

Magnetic hybrid photocatalysts containing TiO₂ nanotube as outer catalytic layer and Fe₃O₄ as the core, with an amorphous carbon intermediate layer, were synthesised, characterised and applied to degradation of phenol under Xenon lamp irradiation. For the composite, Fe₃O₄/C microspheres were surrounded by anatase TiO₂ nanotubes with a diameter of ～8–10?nm. Photocatalytic performance of the Fe₃O₄/C/TiO₂ nanotube (FCT-NT) composites was also evaluated and showed enhanced activity superior to commercial P25 and homemade TiO₂ particles. The outstanding photocatalytic performance of FCT-NT sample could be attributed to its improved surface area and enhanced capability of optical absorption. Notably, the novel photocatalyst showed excellent magnetic behaviour and could be efficiently separated and collected from the wastewater.     

Structures and High Temperature Friction and Wear Performances of Ti/Ni-Doped Carbonaceous Mesophases

Metallic elements Ti and Ni were doped into the coal tar pitch-derived carbonaceous mesophase (CM) through mechanical alloying in a high-energy ball milling apparatus. The structures for the raw and Ti/Ni-doped carbonaceous mesophases were characterized by X-ray diffractometer. The friction and wear behavior of the Ti/Ni-doped CMs as lubricating additives at different applied loads and temperatures were investigated using a MMU-5G high temperature friction and wear tester. Worn morphologies of the lower 45^# carbon steel specimens were observed by scanning electron microscope (SEM). The carbonaceous substances on the worn surfaces were examined by Raman spectroscopic technique. The results have shown that the Ti/Ni-doped CM through mechanical alloying shows an increase in the crystallinity in comparison to that for the raw CM, implying a transition to the more ordered structures caused by the catalytic graphitization at lower temperatures due to the doped Ti/Ni. The Ti/Ni-doped CMs through mechanical alloying, when used as lubricating additives, displayed an obvious high temperature anti-friction and wear resistant effect, and the lager the applied load, the lower the friction coefficient and the wear severity. In addition, as the applied load increases, the carbonaceous substances on the worn surfaces show a rise in the ordered degree, and the corresponding microcrystalline planar size (L _a) for the carbonaceous substances becomes larger.     

Preparation of Carbonized Kapok Fiber/Reduced Graphene Oxide Aerogel for Oil-Water Separation

A carbonized composite aerogel was fabricated based on kapok fibers (KFs) and graphene oxide (GO) through hydrothermal and carbonizing reactions. The as-prepared carbonized kapok fiber/reduced graphene oxide (CKF/RGO) aerogel exhibited special features including light weight, fire resistance, stable structure, hydrophobicity, and oleophilicity. The wettability of the KF/GO aerogel was transformed to hydrophobicity after carbonization, which provided the CKF/RGO aerogel with a distinct ability for oil-water separation. The CKF/RGO aerogel was able to adsorb oil liquids up to 110 times of its own weight. The sorption capacity of the CKF/RGO aerogel was still higher than 90 % of the initial sorption capacity after eleven sorption-combustion cycles of n-hexane solvent.     

骨科植入材料的研究现状及发展趋势

综述了目前临床使用的主要骨科植入材料的研究现状及发展趋势，详细介绍了各种材料的特点、优势和存在的问题，结合各种材料的特点，介绍了它们的主要用途。本文认为目前用于制造骨科植入器械的任何一种材料（无论是金属或合金、陶瓷、高分子材料或碳质材料）均不能同时满足人体生理环境（良好的生物相容性及稳定性、耐腐蚀性）和关节生物力学环境（良好的力学相容性及强韧性、高疲劳性能和耐磨性）的苛刻要求。现有骨科植入器械的有效使用寿命和功能尚不能完全满足患者的要求，有待材料研究专家和临床医学专家共同努力解决。最后，阐述了骨科植入材料的未来发展方向。     

Unsupported cobalt nanoparticles as catalysts: Effect of preparation method on catalytic activity in CO2 methanation and ethanol steam reforming

Cobalt nanoparticles (10–50 nm) have been prepared by different procedures. Materials produced by reduction of cobalt chloride and nitrate by NaBH₄ contain B impurities as borates or borides. They are very active in ethanol steam reforming at 673–773 K with up to 85% hydrogen yield at 773 K. B-free samples obtained by thermal decomposition of Co₂(CO)₈ is slightly less selective to hydrogen, due to its activity in ethanol cracking to methane which is probably poisoned by boron impurities on the other catalysts. B-containing samples are inactive in CO₂ methanation and have weak activity in the reverse water gas shift (RWGS) reaction to CO. B-free nanoparticles have high activity in both CO₂ methanation and RWGS. However, methanation activity is reduced fast by growth of encapsulating carbon species. These particles however also show quite stable activity in RWGS to CO, attributed to CoO impurities.     

Electrochemical properties of Mg-based hydrogen storage materials modified with carbonaceous materials prepared by hydriding combustion synthesis and subsequent mechanical milling (HCS + MM)

Mg₂Ni-based hydride was prepared by hydriding combustion synthesis (HCS), and subsequently modified with various carbonaceous materials including graphite, multi-walled carbon nanotubes (MWCNTs), carbon aerogels (CAs) and carbon nanofibers (CNFs) by mechanical milling (MM) for 5 h. The structural properties of the modified hydrides were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). All of the modified hydrides show amorphous or nanocrystalline-like phases. The hydride modified with graphite exhibits the most homogenous distribution of particles and the smallest particle size. The effects of the modifications on electrochemical properties of the hydride were investigated by galvanostatic charge/discharge, linear polarization, Tafel polarization, electrochemical impedance spectroscopy and potentiostatic discharge measurements. The results show that the maximum discharge capacity, the high rate dischargeability (HRD), the exchange current density and the hydrogen diffusion ability of the hydride modified with the carbonaceous materials are all increased. Especially, the hydride modified with graphite possesses the highest discharge capacity of 531 mAh/g and the best electrochemical kinetics property.