Accessible mesoporous carbon aerogel preparation and its application as ultra-low pt support for oxygen reduction reaction with high catalytic activity

Journal of Porous Materials - Carbon supported Pt and its alloys (Pt/C) are the most practical catalysts for oxygen reduction reaction (ORR). To further reduce scare Pt content in the Pt/C is of...     

外磁场激励下管道弱磁应力内检测特性研究

弱磁应力检测技术支持非接触在线应力损伤检测,在长输油气管道应力内检测技术领域具有巨大的应用潜力。但弱磁信号微弱,易受外界环境干扰,检测结果易出现偏差。为加强弱磁信号的检测能力,基于铁磁材料的微观特性,建立了外磁场弱磁应力检测模型,获得了弱磁信号强度随外磁场强度与施加应力的变化规律,描述了外磁场对弱磁应力检测信号的激励特性,并进行了系统的实验研究。结果表明,弱磁信号的切向峰值与法向零点均位于应力集中区的中心位置,且不随应力与外磁场的变化而发生波动;弱磁信号切向峰值与法向峰峰值随外磁场与应力的增加而增大;外磁场对弱磁应力检测信号的激励作用随外磁场的增加先增大后减小。     

Electrochemical Study on Formation of Dy-Ni Alloy in Molten Chlorides

ＥｌｅｃｔｒｏｃｈｅｍｉｃａｌＳｔｕｄｙｏｎＦｏｒｍａｔｉｏｎｏｆＤｙ－ＮｉＡｌｌｏｙｉｎＭｏｌｔｅｎＣｈｌｏｒｉｄｅｓＴｏｎｇＹｅｘｉａｎｇ；ＬｉｕＧｕａｎｋｕｎ；ＹａｎｇＱｉｑｉｎ；ＨｏｎｇＨｕｉｃｈａｎ，（童叶翔）（刘冠昆）（杨绮琴）（洪惠婵）...     

电动车制动能量再生反馈控制研究

研究了电动汽车制动过程中的能量回馈，设计了混合励磁无刷电动机在汽车制动过程的能量再生反馈控制系统。以脉宽调制调压调速系统为例，研究各种制动态下的能量回馈过程。并将其安装在EV6600电动汽车上进行试验，结果表明：该控制系统可达到10%左右的能量回收效率。     

High-performance Multicrystalline Silicon Ingots Assisted by Recycled Multicrystalline Silicon Block Tailing as Seeds

Silicon - Nowadays, casted multicrystalline silicon is the most important material in photovoltaic industry. In order to reduce the cost of silicon ingots, the recycle of silicon ingot tailings is...     

Reactivity study and kinetic evaluation of CuO-based oxygen carriers modified by three different ores in chemical looping with oxygen uncoupling (CLOU) process

In the chemical looping with oxygen uncoupling (CLOU) process,CuO is a promising material due to the high oxygen carrier capacity and exothermic reaction in fuel reactor but limited by the low melting point.The combustion rate of carbon is faster than the decoupling rate of oxygen carrier (OC).Hence,high tem-perature tolerance and rapid oxygen release rate of CuO modified by three different ores were investi-gated in this study.The kinetics analysis of oxygen decoupling with Cu-based oxygen carriers was also evaluated.Results showed that CuO modified by chrysolite had faster oxygen release rate than that of CuO.Limestone showed obvious positive effect on the oxidization process.The selected OCs could keep stable in at least 20 cycles,for about 1200 min.Shrinking core model (SCM) fitted well for the decoupling process in the temperature range of 1123-1223 K.Reduction rate kinetic information may aid in the development of chemical looping with oxygen uncoupling (CLOU) technologies during reactor design and process modeling.Ternary doped copper oxide with chrysolite and limestone could improve the reactivity of CuO in decoupling and coupling process and also improve the high temperature tolerance.     

Robust Superhydrophobic Fabric for Durability,Self-Cleaning,and Oil/Water Separation via Thiol–Acrylate Polymerization

In recent years, highly efficient oil/water separation materials have brought much attention. It requests superhydrophobic surfaces with a rapid and facile separation process, excellent durability, and large-scale fabrication. Herein, a facile vapor-liquid sol-gel, and free radical polymerization reaction method to prepare the durable and robust superhydrophobic cotton fabric is proposed. Moreover, the fabric can be used for highly efficient and various oil/water separation. It is prepared via a simple two-step process, including a vapor-liquid sol-gel process to deposit with thiols particles, and then followed a free radical polymerization reaction to graft 2,2,3,4,4,4-hexafluorobutyl methacrylate. Scanning electron microscopy and Fourier transform infrared spectrometry prove that the rough structures are generated from the hydrolysis condensation reaction between tetraethyl orthosilicate and 3-mercaptopropyltriethoxysilane. As a result, the synthetic chemical composition provided by the natural fabric and silica nanoparticles synergistically construct a superhydrophobic surface with water contact angles and shedding angle of 158° and 9°, respectively. Additionally, the treated fabric exhibits excellent chemical resistance and self-cleaning ability. Remarkably, the fabric still retains superhydrophobic and excellent mechanical robustness after 30 cycles of various oil/water separation. In summary, the resultant fabrics with excellent chemical resistance, remarkable mechanical robustness, and versatile separation abilities have potential applications in various oil/water separations.     

Preparation of High Strength and Toughness Aramid Fiber by Introducing Flexible Asymmetric Monomer to Construct Misplaced-Nunchaku Structure

High performance fibers with high strength and toughness have great potential in composites, but contradiction between tensile strength and elongation at break makes the preparation to become a current challenge. Herein, an asymmetric structure of more flexible diamine, 3,4′-diaminodiphenyl ether (3,4′-ODA), is introduced into heterocyclic aramid (PBIA) fibers to replace rigid symmetric p-phenylenediamine (PDA). By studying the properties of copolymer (mPEBA) fibers with different ratios of diamine, it is found that the mPEBA fiber reached the optimal mechanical properties with the 30% content of 3,4′-ODA. Compared with homopolymerized heterocyclic aramid fibers, the tensile strength and elongation at break of mPEBA fiber are improved by 26.2% and 38.7%, respectively. Results of X-ray diffraction show that the introduction of 3,4′-ODA structure can increase stretchability of mPEBA fibers, improving the orientation degree during hot-drawing. Molecular dynamics simulations confirm that 3,4′-ODA structure undergoes a conformation transformation to form a straightened chain during hot-drawing, while symmetrical 4,4′-diaminodiphenyl ether (4,4′-ODA) cannot form the same conformation. The misplaced-nunchaku structure is formed based on the special meta-para position of 3,4′-ODA, achieving the synergy of high strength and high toughness.     

Zirconium-Embedded Polyhedral Oligomeric Silsesquioxane Containing Phosphaphenanthrene-Substituent Group Used as Flame Retardants for Epoxy Resin Composites

A zirconium hybrid polyhedral oligomeric silsesquioxane derivative (Zr–POSS–bisDOPO) is synthesized by the corner-capping and Kabachnik–Fields reactions. It is characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR), and then used as a flame retardant in diglycidyl ether of bisphenol A (DGEBA) to endow epoxy resin (EP) with flame retardancy. The flame retardancy, thermal stability, and mechanical properties of the cured EP/Zr–POSS–bisDOPO composites are investigated. The results show that when Zr–POSS–bisDOPO is added by 5–7 wt%, the EP/Zr–POSS–bisDOPO composites pass the UL-94 V-0 rating test. In addition, they have a better flame-retardant effect than pure EP. The combination of Zr atom embedded in the Si O cubic cage and the two phosphaphenanthrene substituent groups in one corner of cubic cage is expected to realize the Zr/Si/P ternary intramolecular hybrid synergistic effect and achieve the possibility of dispersing metal–POSS cages at a sub-micrometer-scale level into polymer matrix. It also proves that Zr–POSS–bisDOPO produces phosphorus-containing free radicals and terminates the chain reactions in gas phase. Meanwhile the Si O Si and Zr O units are retained in the solid phase, which promote the char formation and enhance the flame retardancy. This kind of Zr-doped POSS will be helpful for developing the new metal–POSS hybrid flame-retardant and polymer composites.