碱金属和锌对高炉用SiAlON结合刚玉砖的复合侵蚀

将高炉用SiAlON结合刚玉砖制成外部尺寸为50mm×50mm,内孔尺寸为25mm×25mm的坩埚,分别加入由Na2CO3、K2CO3、ZnO和宝钢高炉现场高炉灰配制的炉渣(其w(Na2O+K2O)=2.75%,w(ZnO)=5.1%)和用K2CO3、ZnO、石墨配制的炉渣(其w(Na2O+K2O)=25%,w(ZnO)=25%),然后分别在还原气氛下于1350℃16h和1100℃40h进行侵蚀试验。将侵蚀后的试样纵向对称剖开,观察渣对试样的侵蚀和渗透情况,进行SEM和EDAX分析。结果表明:碱金属和锌含量不同的两种炉渣对SiAlON结合刚玉砖的侵蚀速度都很小;碱金属侵蚀机理主要是SiAlON与碱蒸气反应生成钾霞石,与渣反应生成铁橄榄石,并参与硅酸盐玻璃相的生成;刚玉颗粒与渣中的FeO、Na2O和K2O反应生成铁铝尖晶石和少量针状β-Al2O3;锌对该砖没有产生明显的化学侵蚀。     

Self-assembly of C60 containing poly(methyl methacrylate) in ethyl acetate/decalin mixtures solvent

[60]Fullerene (C₆₀) was mono-substituted with well-defined poly(methyl methacrylate) (PMMA-b-C₆₀) using the atom transfer radical polymerization (ATRP) technique. The self-assembly behaviors of PMMA-b-C₆₀ in ethyl acetate (EA) and decalin mixtures were studied using laser light scattering (LLS) and transmission electron microscopy (TEM). Homogeneous solutions of PMMA-b-C₆₀ can be obtained in the solvent mixtures containing more than 40 wt% EA, where the molar ratio of decalin to EA is close to 1. For each solvent mixture, unimers coexist with micelles and large aggregates. The sizes of PMMA-b-C₆₀ micelles and aggregates are independent of polymer concentration, confirming that they are produced via the closed association mechanism. For the various solvent mixtures, the weight-averaged molecular weights, M_w of the PMMA-b-C₆₀ aggregates range from 4.1×10⁷ to 12.5×10⁷ g/mol. The hydrodynamic radii of the large aggregate, R_h, vary from 90 to 136 nm, while the z-averaged radii of gyration, R_g, range from 210 to 311 nm. The R_g/R_h value for each solvent mixture is ∼2.3, which is independent of decalin contents in the mixed solvents. The morphological study using the transmission electron microscope suggests that the large aggregates are composed of porous large compound micelles (LCM) in solution.     

Effect of pre-carbonization of petroleum cokes on chemical activation process with KOH

The influence of pre-carbonization of petroleum cokes on the properties of the activated carbon precursors and final carbons activated with KOH was investigated by using TG-DTG, FTIR, XRD, and BET techniques. TG-DTG study revealed the decomposition of volatile species and FTIR analysis identified the presence of C-O, C-O-C, C-O-H and some alkyl species on the surface of the precursors. XRD results indicated that a disorder occurred after the carbonization at 500 °C and an order happened gradually with increasing the temperature. The decreases in the BET surface area and N₂ adsorption capacity coincided with the reduction of the functional species on the precursor surface with the increase of the pre-carbonization temperature. These surface functional species were proposed to play a key role in the porosity development during the KOH activation. First, they reacted with KOH to form the intermediate C-O-K species, then the resultants further reacted with the carbon of the precursor, and finally developed the porous structure. As a result, the surface area and the pore size distribution of the activated carbon can be controlled by optimizing the conditions of the pre-carbonization and activation processes.     

钢筋混凝土框架粘钢加固现场试验分析

本文介绍了某银行大楼框架破损现状及实测资料,分析了致使结构破损的原因及破损程度,提出了粘钢加固的两种方案。并对加固后的结构进行了现场加载试验,得出了位移及应力随荷载变化的规律,讨论了结构加固后其强度、刚度的提高。     

结构粘结剂的试验研究

粘结剂是粘钢加固技术的关键材料,通过对粘结剂的试验研究,得到了粘结剂的拉压试验曲线与材料力学指标以及粘附于各种标号混凝土时,粘结层的抗剪强度;并且还进行了粘结剂的短期流变试验。     

翻斗车的行车制动性能分析

翻斗车有前桥制动和四轮制动两种型式。仅前驱动桥制动,其行车制动性能计算不同于汽车。四轮制动的翻斗车,其空载、满载理想制动力分配曲线与汽车恰相反。     

一种耐水型室内腻子的耐水渗透性测定方法探讨

介绍了一种用于评价耐水型室内腻子的耐水渗透性测定方法,通过测量浸入水中的腻子层在一定时间内渗透的距离反映出腻子的耐水渗透性能。该方法与JG/T 298-2010《建筑室内用腻子》方法中耐水型腻子的耐水性和粘结强度有规律的数据变化关联性,腻子的耐水渗透性越差对应的耐水性和粘结强度也越差。该方法能量值化的测出耐水型腻子的耐水渗透性,避免JG/T 298-2010中耐水性测试的外观评价中的主观影响以及粘结强度测试的不确定度来源多的问题。     

Surface modification with cobalt oxide nanocluster for enhanced surface oxygen exchange reactions of GDC-LSCF membrane: fabrication,electrochemical kinetic properties,and stability

Journal of Applied Electrochemistry - Surface oxygen exchange is a critical reaction process involved in ceramic devices for energy conversion and storage such as gas separation membranes and solid...     

人工合成Al2OTiO5稳定性的初步研究：添加剂对AT的稳定作用

本文探讨了单独加入 MgO、SiO_2和 Cr_2O_3对 AT 的稳定作用,实验结果表明,单独引入 MgO 或 SiO_2时能改善 AT 的烧结性能和力学性能,在不明显提高热膨胀系数的情况下稳定了 AT。而 Cr_2O_3没有起到稳定 AT 的作用。利用 XRD、SEM、EPMA 等手段测试分析了物相组成、晶格常数和显微结构形貌等。