Characterization of the physicochemical properties of the micelles of platelet-activating factor (C18:0)

The purpose of this study was to clarify the physicochemical properties of the micelles of platelet-activating factor (PAF; C_18:0). The critical micelle concentration (CMC) of PAF (C_18:0) was determined (0.20 μM) using fluorescence techniques. The fluidity and the micropolarity of the PAF (C_18:0) micelle were similar to those of the micelle of stearoyl lysophosphatidylcholine.     

Comparison of the effect of lipid A analog E5531 and the lipid A from Escherichia coli on phospholipid membrane properties

The effect of the lipid A analog E5531 on the phospholipid membrane was compared with that of the lipid A from Escherichia coli (EC). E5531 decreased the phase transition temperature of dipalmitoylphosphatidylcholine (DPPC) membrane and increased the fluidity and micropolarity. On the other hand, the effect of EC on the membrane was contradictory. These results suggested that the reason for the difference of biological effects of these two lipid A would be caused by the differences from the effect on the cell membranes.     

Mitigating shrinkage cracking in posttensioning grout using shrinkage-reducing admixture

This study aims to reduce the cracking potential of posttensioning high-performance grout (HG) through use of shrinkage-reducing admixture (SRA). With this regard, an HG mixture was initially developed to possess appropriate fluidity with low bleeding and settling. Various amounts of SRA were subsequently incorporated into the developed HG mixture at 1% and 2% by weight to the cementitious components. A widely used ordinary grout (OG) mixture was also considered for comparison. Test results indicated that the HG mixture exhibited similar flowability to the OG mixture, while imparting much better performance with regard to strength, bleeding, and settling. The addition of SRA to the HG mixture led to higher compressive and tensile strength values after 28 days, lower shrinkage strain, lower maximum internal temperature due to hydration heat, and delayed shrinkage cracking. On the other hand, the degree of restraint due to an uneven surface of duct and the filling capacity of the HG were insignificantly affected by the inclusion of the SRA. Complete filling of ducts was observed for the HG samples. The OG mixture exhibited the smallest shrinkage strain and the best performance with regard to shrinkage cracking resistance; however, the OG mixture resulted in insufficiently filled ducts, leading to atmospheric exposure of prestressing strands. Consequently, the HG mixture with 2% SRA was proposed to be most appropriate for posttensioning grout with regard to the several properties denoted above.     

水煤浆的高浓度磨矿制浆工艺

通过正交试验方法对淮南煤进行实验室的高浓度磨矿成浆性研究,采用统计学软件对试验数据进行分析并得到回归方程,该方程能根据试验参数较好的预测水煤浆的粘度,具有一定的指导意义。在正交试验的基础上研究了多峰连续级配技术对水煤浆成浆性能的影响,结果表明较好的粒度级配可使浆体在同等浓度下获得更佳的流动性和稳定性。     

高流动性3D打印水泥基材料制备及性能研究

为了制备性能良好的3D打印胶凝材料,用碱激发剂对粉煤灰/矿渣胶凝材料进行激发得到了满足可打印性和力学性能的基础材料,并分析了影响胶凝材料性能的最主要因素,基于微观试验结果分析了粉煤灰和碱激发剂对胶凝材料性能的影响机理.结果表明:基础材料的合适掺量和组成为:粉煤灰30％、碱胶比0.56％、碱含量5％、激发剂模数1.0;宜...     

含水量和粒度对粉粒状物料流动性的影响

本文应用力学的有关原理，采用休止角，压缩率，刮铲角和无一系数法，对硅酸盐工业生产中常用的粉粒状料进行了流动性测定，定量地研究了料中的含水量和料的粒度的变化对粉粒状流动性的影响。     

不发火混凝土的配制与性能研究

对骨料的不发火性进行检验,采用白云石及石灰石作为骨料配制不发火混凝土,研究使用不同的骨料对水泥胶砂和混凝土工作性、强度变化的影响。结果表明,不发火骨料的胶砂流动度较高;以白云石为骨料配制的中低强度混凝土前期强度较低,后期强度满足要求,而以石灰石为骨料配制的中低强度混凝土前期和后期强度都相对较高。     

减水剂对球粘土-水系统流变性能影响及机理研究

研究了Na2CO3、Na2SiO3及复合减水剂对球粘土-水系统流动性及泥坯可塑性的影响。结果表明：Na2CO3、Na2SiO3、复合减水剂的最佳加入量均为0．1％,泥浆系统的Zeta电位升高,流动性增强,减水剂特别是Na2CO3的添加可以显著的提高粘土泥坯的可塑性。机理分析得出：球粘土中有机腐殖酸物质的存在对减水剂作用效果有很大影响,Zeta电位变化与可塑性变化的是相关的。     

浇注系统对AZ91镁合金消失模铸造流动性的影响

研究了在消失模铸造中,直浇道高度、内浇道面积、浇口比和内浇道位置对ＡＺ９１镁合金流动性的影响;结果表明,在负压条件下采用开放式浇注系统时流动性随攻道距离的增加而有所降低,除此之外,浇注系统结构对流动性的影响不大。     

混合稀土对Cu-30Ni-20Fe-5Al微观组织及流动性的影响

采用真空熔炼制备不同稀土含量的Cu-30Ni-20Fe-5Al合金,研究了稀土含量对铸态Cu-30Ni-20Fe-5Al合金组织和流动性能的影响及内在机制。结果表明,铸态Cu-30Ni-20Fe-5Al合金由α-Cu和NiAl化合物两相组成,NiAl相以不规则环状分布,其不规则环状内外两侧存在较大的Fe元素偏析;加入混合稀土后,随混合稀土含量的增加,铸态合金中NiAl相变为球状、棒状独立存在,晶界处出现富稀土相的析出;当混合稀土含量达到0.78%时,不规则环状NiAl相球化效果最好;在流动性试验中,加入0.78%混合稀土元素与不加混合稀土元素比较,自制螺旋试样长度增加25%,合金的流动性能最好。