Enhanced wettability and thermal stability of polypropylene separators by organic–inorganic coating layer for lithium‐ion batteries

Organic–inorganic coating polypropylene separators were developed by introducing SiO₂ nanoparticles through sol–gel process, where polydopamine was used as an intermediate layer. Scanning electron microscopy results showed the coating layers have highly porous structure, which was beneficial for liquid electrolyte uptake. Compared with pristine polypropylene separator, the ceramic separators showed improved thermal stability, higher ionic conductivity, and lower interfacial impedance. The cells employing the ceramic separators delivers excellent discharge capacity (retention = 75%) and coulombic efficiency up to 98% at 2 °C rate after 100 cycles. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46478.     

Effect of the composition and degree of crosslinking on the properties of poly(l‐lactic acid)/crosslinked polyurethane blends

Poly(l ‐lactic acid)/crosslinked polyurethane (PLLA/CPU) blends which were prepared via reactive blending of PLLA with poly(?‐caprolactone) (PCL), glycerol and 4,4′‐methylenediphenyl diisocyanate showed excellent toughness. The effects of the composition of the mixture and degree of crosslinking of CPU on the toughness of the PLLA/CPU blends (80/20 w/w) were studied in detail. Dynamic mechanical analysis and rheological measurements were used to characterize the structure of the in situ formed CPU in the PLLA matrix. A novel netlike phase structure was observed when the average molecular weight of PCL and degree of crosslinking were 1 kDa and 10%, respectively. The impact strength of the blend was enhanced from 2.2 kJ m^?2 for pure PLLA to 62.4 kJ m^?2; meanwhile, the elongation at break was increased to 489.8%. Therefore, the mechanical properties of PLLA/CPU blends can be easily tailored by tuning the composition of the mixture and the degree of crosslinking of CPU. © 2018 Society of Chemical Industry     

Non‐isothermal crystallization kinetics of Al2O3‐YAG amorphous ceramic coating deposited via plasma spraying

Crystallization kinetics of the newly developed Al₂O₃‐Y₃Al₅O₁₂ (YAG) amorphous ceramic coating fabricated by atmospheric plasma spraying (APS) were investigated via differential scanning calorimetry (DSC) under non‐isothermal conditions. The phase compositions and microstructure of the as‐sprayed coating were characterized by X‐ray diffraction (XRD) and Scanning electron microscopy (SEM). The glass transition temperature T_g, the onset temperature of crystallization T_c and the peak temperature of crystallization T_p presented heating rate dependence. The related kinetic parameters of activation energies (E_g, E_c, E_p) and Avrami exponents (n) were quantified using various methods including Kissinger, Augis–Bennett, Ozawa and Matusita–Sakka, etc., to understand the phase transition mechanism and crystallization process in depth. A series of parameters including devitrification interval ΔT, thermal stability (T_c, E_c), nucleation resistance E_c/RT_g and fragility index F were quantified in order to evaluate the nucleation mechanism, crystallization behavior and thermal stability of Al₂O₃‐YAG amorphous ceramic coating. Excellent thermal stability was witnessed in the studied coating. Furthermore, the YAG crystalline phases can be reasonably controlled and independently precipitated from the amorphous matrix via proper annealing.     

高功率微波等离子体环境下甲烷浓度对金刚石膜的影响

在实验室自制的10 kW微波等离子体化学气相沉积装置中,分析了高功率微波等离子体环境中甲烷浓度对金刚石膜生长的影响。利用等离子体发射光谱诊断分析高功率微波等离子体放电环境的特征,同时利用SEM及Raman光谱对不同沉积条件下获得的金刚石膜的形貌及质量进行表征,以确定高功率微波等离子体环境下金刚石膜生长的最优甲烷浓度范围。实验表明在保持微波功率为5000 W,CH₄/H₂≤1%时,金刚石膜中二次形核现象明显,晶粒尺寸较小;CH₄/H₂≥2.5%时,金刚石膜可获得较大的晶粒,但易于产生孪晶体;CH₄/H₂=1.5%～2%时,可获得晶粒完整且质量较高的金刚石膜。     

Corrosion resistance of Al–Cr-slag containing chromium–corundum refractories to slags with different basicity

Al–Cr slag is the solid waste generated by the smelting of Cr metal. It presents a range of environmental hazards. This study addressed the corrosion resistance of Al–Cr slag containing chromium–corundum refractories to slags with different basicity. Herein, we provide suggestions for the use of Cr–corundum of different basicity in kilns. Al–Cr slag, brown fused Al₂O₃, and chrome green were used as the raw materials, with pure calcium aluminate cement being used as a binder. The brick samples, prepared using different blends of chrome green and corundum, were fired at 1600?°C, and subsequently subjected to a slag corrosion test. After corrosion by slag of different basicity, the phase composition and microstructure of the sample were analyzed by X-ray diffraction, energy dispersive spectrometer and scanning electron microscopy. There were two major findings. First, Cr–corundum brick made from Al–Cr slag has a better slag corrosion resistance than that made from Cr₂O₃ and brown fused Al₂O₃. Second, Cr–corundum brick made from Al–Cr slag has superior corrosion resistance to slag with a CaO:SiO₂ ratio of 2:1.     

HCN、COS和CS2催化水解及其水解产物协同净化的研究进展

氰化氢（HCN）、羰基硫（COS）、二硫化碳（CS₂）广泛共存于黄磷尾气、焦炉煤气、碳一化工等化工行业废气中,目前大多数研究局限于3种气体的单独脱除,3种气体同时脱除的研究鲜有报道,而3种气体的协同脱除势在必行。催化水解法能够将HCN转化成NH₃,COS和CS₂水解成H₂S。NH₃和H₂S可以分别被催化氧化为N₂及S,S可以回收利用。一步法实现HCN、COS和CS₂的水解及水解产物NH₃和H₂S的催化氧化的催化剂开发是该技术的核心问题,本文针对近几年3种气体水解催化剂的相关研究成果进行了综述,包括负载型催化剂和非负载型催化剂,与此同时,针对水解产物NH₃和H₂S的催化氧化的协同净化技术进行了分析,旨在为后续3种气体同时催化水解及协同净化其水解产物催化剂的开发提供理论指导,为低温环境下协同催化水解HCN、COS和CS₂,并利用原料气中的氧一步法净化水解产物技术的未来发展及应用提供参考。     

Facile preparation of highly dispersed Pt nanoparticles supported on heteroatom-containing porous carbon nanospheres and their catalytic properties for the reduction of 4-nitrophenol

Heteroatom-containing porous carbon nanospheres with a high surface area were firstly fabricated by pyrolysis of poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) nanospheres which were fabricated by a facile polycondensation between hexachlorocyclotriphosphazene and 4,4′-sulfonydiphenol. Then the porous carbon nanosphere-supported Pt nanoparticles (Pt NPs@C-PZS) were synthesized by a simple microwave reduction method, during which Pt NPs were highly dispersed on the surface of carbon supports. The surface morphologies and chemical composition of the as-obtained C-PZS and Pt NPs@C-PZS nanocomposites were characterized by SEM, TEM, XRD, XPS, and Raman spectroscopy. Characterization results showed that the Pt NPs with an average diameter of 2 nm was well anchored onto the surface of C-PZS nanospheres. In addition, the as-prepared Pt NPs@C-PZS nanocomposites exhibited an excellent catalytic capability towards the reduction of 4-nitrophenol to 4-aminophenol by excessive sodium borohydride (NaBH₄) at room temperature.     

三维打印磷酸镁水泥复杂艺术品的工艺研究

为了获得任意复杂形状的水泥艺术品,提出基于磷酸镁水泥(MPC)粉末,以硼砂溶液作为粘接剂,通过粉末床三维打印技术制备了磷酸镁水泥试样和复杂艺术品.研究了三维打印磷酸镁水泥试样的形状精度,并探讨了硼砂溶液对磷酸镁水泥力学性能的影响;测试了磷酸镁水泥在空气里养护及水保养条件下的抗压强度,并利用XRD和SEM分析了磷酸镁水泥的水化产物的物相组成和微观形貌.结果表明,三维打印磷酸镁水泥成型精度较高,尺寸误差在2.5％以内,打印坯体抗压强度达到1.35 MPa;磷酸镁水泥经水护保养后,抗压强度可提升至2.26 MPa,在水中浸泡后抗压强度达到了9.44 MPa;最后,利用优化的材料方案和工艺参数,三维打印了复杂形状扭环和齿轮水泥艺术品.     

在我国建立电力市场是必然趋势

本介绍了美国和英国电力市场的发展情况：根据我国当前电力工业的趋势，论证了建立各级电力市场的必要性，说明了电力市场给社会各方带来的效益。     

Hot zones formation during regeneration of diesel particulate filters

A diesel particulate filter (DPF) is used to remove particulate matter (PM) from the diesel engine exhaust. The accumulated PM is periodically removed by combustion, which sometimes leads to excessive temperature excursions that melt the ceramic filter. This behavior cannot be explained by operation under stationary feed conditions. We propose that these temperature excursions are a dynamic effect following a rapid change in the driving mode while the DPF is being regenerated. Specifically, a rapid decrease in the exhaust temperature can lead to a counterintuitive large transient temperature rise above that which would exist under a higher stationary feed temperature. This unexpected behavior is similar to the well‐known wrong‐way behavior in packed‐bed reactors, even though the axial‐dependent flow through the filter in a DPF is rather different from the constant axial flow through a packed bed. We present simulations that provide insight about the dependence of the amplitude of this wrong‐way temperature rise on the filtration velocity, the PM loading, dimensions of the DPF, and the amplitude of the rapid temperature decrease and when it occurs after the start of the regeneration. The insight provided by these simulations will help develop operation and control protocols that circumvent or at least decrease the probability of the occurrence of the destructive melting of the DPF. © 2010 American Institute of Chemical Engineers AIChE J, 2011