Hexafluorozirconic acid based surface pretreatments: Characterization and performance assessment

A new phosphate-free pretreatment from Henkel Corp. named TecTalis^®, was investigated. The treatment bath is composed of dilute hexafluorozirconic acid with small quantities of non-hazardous components containing Si and Cu. The corrosion resistance of treated steel was compared to samples treated in a phosphate conversion coating bath, in simple hexafluorozirconic acid and in TecTalis without the addition of the Cu-containing component. Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) were used to characterize the coating surface morphology, structure and composition. A Quartz Crystal Microbalance (QCM) was used for studying film growth kinetics on thin films of pure Fe, Al and Zn. Electrochemical Impedance Spectroscopy (EIS) was performed on treated and painted steel for studying long-term corrosion performance of the coatings. The phosphate-free coating provided long-term corrosion performance comparable to that of phosphate conversion coatings. The coatings uniformly cover the surface in the form of 10–20 nm sized nodules and clusters of these features up to 500 nm in size. The coatings are usually about 20–30 nm thick and are mostly composed of Zr and O with enrichment of copper at randomly distributed locations and clusters.     

微波辐射合成4-溴-4＇,4″-二甲基三苯胺

以氢氧化钾（4）为缚酸剂,CuCl、1,10-菲啰啉（3）为催化剂,在微波辐射条件下,对碘甲苯（1）和对溴苯胺（2）在甲苯（5）中反应合成了4-溴-4＇,4″-二甲基三苯胺,其结构经1HNMR和IR表征。由正交实验确定最佳工艺条件为：1用量为24 mmol,n（1）∶n（2）∶n（3）=2.4∶1.0∶4.0,微波功率为250 W,于105℃反应120 min,收率77.1%。     

沥青基碳纤维的制备及应用研究进展

碳纤维是一种力学性能优越的特种纤维,广泛应用于国防、航空航天、医用、工业、体育等众多领域。沥青基碳纤维可由沥青经萃取、缩聚、纺丝、氧化、碳化而制得。阐述了沥青基碳纤维的发展背景、制备原理及应用领域等。     

沧州南部典型区近30年来气温演变特征分析

文中主要分析了沧州南部典型区近30年来气温演变情势,分析了其统计特征、年内变化趋势性和年代际变化、持续性、突变性和周期性,得出了一定的规律性,为深入研究本区域与气温有关的课题打下了基础。     

腐植酸物质在商业中的应用——现今世界文献综评

连续查阅现今世界文献,关于“腐植酸”文章已经发表了八千篇之多,查阅工作是在美国康乃迪克州内瑞克斯多斯进行的,这项工作可以追朔到七十年代,查阅了二十七种基础资料,包括美国和全世界的专利文件,化学文摘服务社材料,农业,生物文摘,水资源文摘,工程索引和生物科学集录等,收集到的参考文献其数量之多,各地生产的腐植酸物质的明显差异性及全球资源的广泛分布亦给人留下深刻印象。     

国内外稠油和沥青VAPEX技术发展现状与分析

自1991年Roger Butler提出稠油和沥青的蒸汽萃取（VAPEX）技术以来,VAPEX已经成为一个非常有前途的开采工艺。最主要的原因是,相对于其它的采油工艺,VAPEX具有环境友好、成本低的特点。本文详细综述了国内外VAPEX技术最新发展现状,探讨了VAPEX开采稠油技术机理,评述了VAPEX技术优点及技术局限性,展望了VAPEX技术应用前景,提出了今后发展方向。     

A corrosion study of nickel–copper and nickel–copper–palladium welding filler metals

In an effort to reduce the release of fumes containing carcinogenic Cr⁶⁺ during arc welding of stainless steel, Cr‐free filler metals for welding of SS304 have been developed. Corrosion studies were carried out on 304L stainless steel samples welded with these Cr‐free consumables. The corrosion properties of gas tungsten arc (GTA) and shielded metal arc (SMA) welds fabricated with Ni? Cu and Ni? Cu? Pd consumables were found to be comparable to those of welds fabricated with SS308L, the standard filler metal used with SS304. Although the breakdown potentials of the welds made using both welding processes were lower than that of the SS308L GTA weld, the repassivation potentials of these welds were much higher. Generally, the repassivation potential is a more conservative measure of susceptibility to localized corrosion. Accordingly, the Ni? Cu and Ni? Cu? Pd welds were more resistant to crevice corrosion than SS308L welds. The addition of a small amount of Pd improved the corrosion resistance relative to Ni? Cu welds, which is consistent with previous studies from specially‐prepared button samples and bead‐on‐plate samples. Other corrosion studies such as creviced and uncreviced long time immersion, atmospheric exposure, and slow strain rate testing suggest that Ni? Cu? Pd filler metal can be a potential replacement for the conventional SS308L filler metal for joining SS304.     

保险粉的盐母液制备硫代硫酸钠

研究了以保险粉的盐母液为原料 ,经加热、加硫、空气氧化、浓缩结晶 ,制备硫代硫酸钠并回收氯化钠的新工艺 ,具有较好的经济和社会效益     

Synthesis and characterization of triacylglycerols containing linoleate and linolenate

Triacylglycerols containing linoleate and linolenate found in vegetable oils were synthesized in gram quantities for oxidation studies. Two acylation methods were examined to convert diacylglycerols or monoacylglycerols to the desired triacylglycerols. Acylations with fatty acid and 1,1′-dicyclohexylcarbodiimide in the presence of 4-dimethylaminopyridine were more rapid, gave triacylglycerols of better isomeric purities and generally better overall yields than the acylations with acid chloride in pyridine. The functional and isomeric purity of the synthetic triacylglycerols were investigated by thin-layer and gas-liquid chromatography of the methyl esters, by lipase hydrolysis, and by¹³C NMR. Quantitative¹³C NMR provided a valuable tool to determine isomeric structures of the unsaturated triacylglycerols and complemented the lipase hydrolysis method. The triacylglycerols purified by dry column chromatography were obtained in the following respective percent yields, functional and isomeric purities: LLLn, 92.1, 99.4, 98.1; LLnLn, 91.7, 99.2, 97.4; LLnL, 84.2, 99.7, 98.9; and LnLLn 77.5, 97.8, 99.0 (where L=linoleoyl and Ln=linolenoyl glycerol residues). These synthetic triacylglycerols are valuable models to elucidate the interrelationship of unsaturated fatty acids on the oxidative stability of polyunraturated vegetable oils. Presented in part at the AOCS meeting in Phoenix, AZ in May 1988.     

富马海松酸环氧树脂的制备及漆膜性能

通过松香(RA)与富马酸(FA)高温下的Diels-Alder反应合成了富马海松酸(FPA),并利用碳谱(13CNMR)、电喷雾质谱(ESI-MS)、红外光谱(IR)对其进行了表征;通过FPA与丁二醇二缩水甘油醚(BDGE)、己二醇二缩水甘油醚(HDGE)的酯化反应合成了松香基环氧树脂预聚体(FB、FH),测试了预聚体与固化剂不同配比下固化物的漆膜性能;结果表明,当n(活性氢)/n(环氧基)在1.0、1.2时,漆膜的硬度大于HB,附着力小于2级,T-弯实验小于2 T,耐冲击强度大于9.8 J,耐化学性能良好。