Modern solid lubrication: Recent developments and applications of MoS2

An important and growing field of lubrication lies in the use of solid films, although they are in general more expensive than oils or greases, and require specialist attention both in mechanical design and in coating application techniques. In this paper, the general classification of solid lubricant types is reviewed, along with the reasons for choosing, and methods of depositing, solid lubricants, in particular MoS₂. The best‐performing and most flexible technique for making MoS₂ films is by physical vapour deposition (PVD), and the variants of that technology are considered. The intrinsically lubricating, lamellar structure of pure MoS₂ is described, along with a brief summary of its wear and failure modes. Present applications for lubrication by MoS₂ in spacecraft and dry machining are outlined, as are anti‐adhesive uses in extruding and moulding. The current state of the art of modification of MoS₂ films consists in the addition of dopants (co‐sputtering), in multilayering as a series of films, each fulfilling a specific task, or in stacking repeating nano‐metre‐scale films. Composite films of MoS₂ islands in a hard film matrix are also being developed.     

独立新风系统(DOAS)研究(3):常规风机盘管独立新风系统

分析了以风机盘管机组为空调末端装置,以普通冷水机组为冷源的独立新风空调系统的特点。结合设计实例,介绍了该空调系统的设计方法。详细说明了如何实现风机盘管的干工况运行。     

Gelation of poly(vinyl alcohol)/water/dimethylformamide solutions and properties of dried films

The properties of solutions for syndiotacticity-rich poly(vinyl alcohol) (s-PVA)/dimethylformamide (DMF)/water systems, the gelation of the s-PVA solutions, and the properties of the dried s-PVA gel films were examined. From the results of the dissolution temperature of the polymer, the gelation temperature of the solutions, the melting temperature of the gels, and the compressive modulus of the gels, the solubility of the polymer was the highest at DMF contents of 10–20 vol %. The maximum dynamic tensile modulus of the drawn (×18) films obtained from the dried gel films with a DMF content of 10 vol % was 54.9 GPa at 20°C. The orientation of the polymer chains in the amorphous regions was higher than that in the crystalline regions. The orientation of the polymer chains in the amorphous regions for the drawn films with a DMF content of 10 vol % was higher than that for the drawn films with a DMF content of 60 vol %. The orientation of the polymer chains in the amorphous regions was considered to play an important role in the properties of high strength and high modulus. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1661–1667, 1998     

干水法制备核壳聚合物微球及其性能评价

以疏水SiO2、单体、引发剂和交联剂为原料,水为溶剂,采用干水法制备核壳聚合物微球PMS@SiO2,分别考察了SiO2疏水性、硅水质量比、搅拌速度和搅拌时间对形成稳定干水微反应器的影响。以过硫酸铵和亚硫酸氢钠为引发剂,N,N''-亚甲基双丙烯酰胺为交联剂,通过正交实验对内核水相发生聚合反应的条件进行了优化。采用傅里叶变换红外光谱仪、热重分析仪、激光粒度仪、扫描电子显微镜和透射电子显微镜对微球的化学结构、热稳定性及微观形貌进行了表征,评价了微球的吸水膨胀性能和调驱性能。结果表明,核壳聚合物微球PMS@SiO2的最佳制备条件为：SiO2-R812S与水相质量比1∶10,搅拌速度12000 r/min,搅拌时间120 s,交联剂用量0.1%（以单体总质量为基准,下同）,引发剂用量0.15%,反应温度50 ℃,反应时间4 h。与常规聚合物微球PMS相比,该微球在90 ℃环境中水化20 d,膨胀倍数约为5.0,具有缓膨特性。物模调驱实验结果表明,PMS@SiO2的封堵率达90.39%,残余阻力系数为10.409,采收率增幅可达34.02%。与PMS相比,其采收率提高了11.89%,具备良好的调驱性能。     

Preparation and characterisation of oil-containing POM/PU blends

Polyoxymethylene (POM), one of the major engineering thermoplastics, has high strength and stiffness, excellent chemical resistance and superior antifriction and wear resistance. It suffers, however, from poor impact resistance due to its higher crystallinity. In this study we have investigated how to improve the toughness of POM by blending polyurethane (PU) with POM using dual-roller compaction. The influences of PU, silicone oil, a surfactant, and fillers such as ultra-high molecular weight polyethylene (UHMWPE), polytetrafluoroethylene (PTFE), graphite and carbon black, on the mechanical properties of oil-containing POM/PU blends and its self-lubrication performance in dry sliding against AISI1045 steel are examined. The results show that blends of POM with 10 wt.% PU reached the maximum notched Izod-impact strength. The best processing method for oil-containing POM/PU blends, and the optimal compositions of modified POM/PU blends were also determined.     

干法合成淀粉阳离子絮凝剂

研究了干法合成阳离子淀粉絮凝剂的方法。结果表明,制备阳离子淀粉絮凝剂的最佳工艺条件为:在反应体系中水的质量分数为35%,阳离子醚化剂与NaOH混合液温度低于10℃,阳离子醚化剂与淀粉质量比为0.35,NaOH与阳离子醚化剂质量比为1.40,反应温度90℃,反应时间4h。在此条件下合成的阳离子淀粉絮凝剂相对黏度为2.0mPa·s。     

赤泥微波干法固定碱及其机理分析

赤泥是通过拜耳法精炼铝土矿产生的一种强碱性工业固体废物。以遵义某拜耳法氧化铝厂排出的赤泥为样品,开发出微波干法快速固碱技术,并就其干法固碱原理进行研究。研究表明,赤泥经过微波干法固碱,功率为392 W,微波频率2 450 MHz,波长122 mm,仅需要40 min,其pH可以从10.88降低至8.11,固碱过程不产生二次污染物。通过XRD和SEM分析发现,赤泥成分、外貌颜色、表观形态及粒径都存在变化。     

考虑干密度影响的压实黄土土水特征与渗透特性试验研究

为了研究干密度对压实黄土土水特征、渗透特性的影响,用一维瞬时土柱渗透仪开展了不同干密度压实黄土的常水头渗透试验,得到了入渗量、体积含水率、吸力时程线与土水特征曲线;利用瞬态剖面法计算了非饱和渗透系数,分别得到其与吸力和饱和度的关系曲线.结果表明:干密度增大,入渗量时程线趋于平缓,吸力和体积含水率时程线转折点后移,陡变段...     

DS-1高硅奥氏体不锈钢板在硫酸工业中的应用

根据硫酸工业生产的需要,研制了用于高温浓硫酸的DS-1高硅奥氏体不锈钢板材,在合金成分的设计和制造工艺获得成功后,将该种材料投入了工业化应用,用于硫酸生产装置中的干燥塔和吸收塔作为内衬及填料支撑装置(代替瓷砖砌筑),以及用于制造分酸器。经过几年的使用实践证明,DS-1、DS-2高硅奥氏体不锈钢不但具有优良的耐热浓硫酸腐蚀性能,而且具有良好的冷热成型工艺性能和焊接性能。     

中高温烟气干燥脱硫废水过程研究

脱硫废水零排放(ZLD)已成为现阶段环境治理的趋势,传统的治理方法具有高成本、难维护等缺点,因此提出一种利用中高温烟气干燥电厂脱硫废水的新技术。通过将选择性催化还原(SCR)脱硝后的热烟气引入喷雾干燥器,雾化废水使其与烟气充分接触,经干燥进入空气预热器后的原烟道。结果表明:抽取锅炉烟气量的7%左右可干燥脱硫废水2.5 t,使锅炉热效率降低0.68%左右,影响较小。干燥后烟气酸露点温度从93.20℃提高到96.72℃,不会腐蚀空气预热器等后续工艺设备,同时该技术有利于静电除尘器(ESP)、湿法烟气脱硫(WFGD)系统的运行,利用中高温烟气干燥脱硫废水是可行且有效的技术方法。