Oil Degradation in a Diesel Engine with Dual-Loop Lubricating System

A common lubricating oil sump is used in most modern internal combustion engines for cooling, wear protection, and friction reduction. This requires compromises during base oil and additive selection as a result of differing needs for lubricant performance in engine subsystems. The use of a dual lubricating loop, providing separate oil sumps for the power cylinder and valve train subsystems, was investigated experimentally to determine the effect of system segregation on oil degradation. A small diesel engine was modified, installed in a commercial generator unit, and operated for one oil drain cycle. Oil sampling was tailored to assess base and acid numbers, oxidation, soot concentration, water content, and viscosity changes. The experiment complemented an earlier study that investigated the fuel economy benefits of such a lubricating configuration. These include longer drain intervals for the cylinder head and power cylinder subsystems, improved wear performance for the valve train, and opportunities for alternative material selection during engine design. The experiment demonstrated protection of the valve train subsystem from soot contaminants in the power cylinder. Lower total acid number and oxidation tendency was also observed in the valve train.     

分散剂的合成及其在锂离子电池涂料中的应用

针对电池涂料涂布要求,由苯乙烯磺酸钠、甲氧基聚乙二醇甲基丙烯酸酯等单体共聚合成了磷酸铁锂锂离子电池涂料分散剂。通过正交试验法对配料比进行优化,最佳配比(以丙烯酸为基准计算)为:丙烯酸100%、马来酸酐10%、丙烯酸丁酯6%、苯乙烯磺酸钠10%、甲氧基聚乙二醇甲基丙烯酸酯60%。在最优配料比条件下合成该分散剂,进一步探讨了分散剂用量对涂料流变性影响,结果表明:固含量为77.1%,分散剂用量为活性物质磷酸铁锂质量的0.3%时,涂料初始黏度为1 332 m Pa·s,静置90 min后黏度为1 656 m Pa·s,符合电池涂布工艺要求。     

Dispersion and densification of nano Si–(Al)–C powder with amorphous/nanocrystalline bimodal microstructure

The dispersion behavior and densification of nano Si–(Al)–C powder with amorphous/nanocrystalline bimodal microstructure were investigated. The Si–C powders synthesized by a mechanical alloying (MA) process had a near‐spherical shape with an average particle size of 170 nm. A solid loading of 62 vol% was achieved using polyethyleneimine (PEI) as a dispersant. The optimum dispersant amount was 1 wt% based on zeta potential, sedimentation, and viscosity analysis data. The high zeta potential value (73 mV) compared with that of the commercially available SiC (65 mV) was caused by modified surface properties and consequent promotion of the cationic dispersant adsorption. A Si–Al–C slurry containing 6.5 wt% of sintering additives with a solid loading of 60 vol% was also prepared. The relative density of the dried Si–Al–C slurry was 63.3% without additional compaction, which could be densified at 1650°C at a pressure of 20 MPa using a spark plasma sintering furnace.     

Poly(methacrylate)‐derived diblock dispersant for TiO2 in aqueous suspensions

In this paper, we propose a newly designed dispersant, ammonium poly(methacrylate)‐block‐poly(2‐phenoxyethyl acrylate) (PMA‐b‐PBEA), and our rheological and zeta potential test results verify its superior dispersion efficiency for aqueous suspensions in comparison to the commercial dispersant ammonium polyacrylate (PAA‐NH₄). The extremely high dispersion efficiency of PMA‐b‐PBEA correlates closely to its diblock structure, which simultaneously exhibits a less polar anchoring head group and a water‐dissociable stabilizing moiety. The unique structure of PMA‐b‐PBEA accounts for its high powder adsorption effectiveness, which is demonstrated in its adsorption capability being double that of PAA‐NH₄.     

湿法超细研磨中无机材料浆体的流变性研究

概述了无机材料超细粉体机械研磨制备中浆体的流变性能、流变性能的表征方法和流变学行为的经验方程模型.对影响超细粉浆体流变性能的参数(如固相含量、颗粒粒径和分布、形状、温度、pH值及分散剂)进行了讨论.对浆料流变学性能进行最优化以提高超细粉体的产量,降低能耗,提高产品细度.提出了今后的研究重点应放在湿法超细研磨过程中分散剂种类及用量对浆体流变学性能改变机理的研究,并建立可描述浆体流变性能与粉碎参数、分散剂用量、能耗和颗粒大小的数学关系.     

煤对CWM分散剂吸附性能的研究

本文选择三种具有代表性ＣＷＭ分散剂，借助ＦＴ－ＩＲ和ＸＰＳ等现代实验手段对分散剂在煤表面的吸附性能进行了分析，揭示了ＣＷＭ分散剂吸附特征，为从组成和结构上选取优良分散剂提供实验依据。     

分散剂对复合电刷镀Ni-P-碳纳米管工艺影响的研究

研究了羟乙基纤维素作分散剂对电刷镀Ni-P-碳纳米管工艺的影响。结果表明，羟乙基纤维素用量不同，电刷镀液中碳纳米管的颗粒尺寸有很大差别，不足或过量的羟乙基纤维素都影响碳纳米管的颗粒尺寸分布。超声搅拌时间长短、溶液pH值是影响电刷镀液中碳纳米管颗粒尺寸的另一个因素。当羟乙基纤维素用量为0．6g／L，溶液pH在5．7左右，碳纳米管颗粒平均粒径最小，刷镀层的碳纳米管成较好的分散状态，表面结晶更细致均匀。     

水溶性聚合物型颜料分散剂的研制

合成了用于水性体系的聚合物型颜料分散剂——苯乙烯和丙烯酸的共聚物，并采用红外和核磁对所合成的聚合物的结构进行了表征，确定为目标产物。研究了单体摩尔比、反应温度和链转移剂的用量对聚合物的分散性能的影响；确定了苯乙烯和丙烯酸的摩尔比为1．0～1．3、反应温度为90．0～110．0℃、链转移剂的用量为单体总质量的4．0％～6．0％。测试了不同相对分子质量的聚合物的特性粘度，当特性粘度等于15～16时，对颜料的分散性能较好。与日本的同类产品（Johnson Polymer ChemicalLtd．）J-68进行了对比，对颜料黄（C．I．P．Y．3）进行粒度分布的测试，平均粒径小于J-68，而重均比表面积则大于J-68，分散性能优于J-68。     

纳米TiO_2在水中分散性能的研究

通过选取几种无机类、高分子类分散剂对纳米TiO2 粉体在水中的分散性能进行了比较。研究结果表明 ,加入的分散剂用量不同 ,分散效果有很大差别 ,不足或过量的分散剂影响了粉体的分散率。将两类分散剂按一定的比例复配使用 ,分散效果显著提高。通过透射电子显微镜 (TEM )观察纳米TiO2 的微观形貌 ,并对TEM照片进行了分析     

SiC晶须的分散研究

利用离心沉降浊度法对SiC晶须在4种不同分散剂中的分散行为进行了研究,探讨了不同分散剂的分散效果,并对其分散机理进行了分析。结果表明,分散剂的分散能力顺序为氨基甲基丙醇AMP-95>聚丙烯酸铵盐DP518>聚丙烯酸钠盐DP270>水性硅烷A-1230。