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在AR2000ex型流变仪上对沉淀碳酸钙(Precipitated calcium carbonate,PCC)在PEG(聚乙二醇)悬浮体系进行稳态剪切流变实验。通过2种方法来改变分散体系黏度:1)以PEG200(相对分子质量为200)为连续相,分散体系以10℃为间隔从10℃上升至50℃;2)在30℃用相同的聚合物3种不同相对分子质量的PEG(PEG200、PEG400和PEG600)。结果表明随着温度升高,PCC/PEG200分散体系的临界剪切速率越来越大。在剪切增稠区内流动指数N随温度升高而降低,稠度系数K随着温度升高而升高。临界剪切速率以及临界剪切黏度与温度严格满足Arrhenius关系:η=A exp[Ea/(RT)]。研究发现随温度的变化临界剪切应力不变。随着PEG的相对分子质量增加,分散体系的黏度增加,临界剪切增稠速率减小。PCC粉末的分形结构以及聚集体的形貌使得体系的相对黏度远大于硬球体系的相对黏度。 相似文献
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甘油锌的合成及其光稳定作用研究 总被引:2,自引:0,他引:2
介绍了甘油锌配合物的合成方法,研究了影响产物合成的主要因素,测试了产品的红外光谱、物化性能及光稳定作用。结果表明:在甘油与氧化锌质量比为7:1,260℃及0.5gZA作用下反应1.5h得到的甘油锌不仅光稳定性能好,而且无毒、不着色。 相似文献
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The binary complexes of terbium with benzoic acid and its derivatives (phthalic acid, iso-phthalic acid, oaminobenzoic acid, salicylic acid, sulfosalicylic acid) were synthesized and their compositions were identified by elemental analyses. UV, IR of the complexes were investigated. The UV spectra indicate that the complexes‘ ultraviolet absorption is mainly the ligands‘ absorption, but the location of peak drifts. The IR spectra show that the IR spectra of complexes are different from those of free ligands, and the band at 400 - 500 cm^-1 , due to the stretching vibration of Tb--O, is absent for free ligands. The fluorescence properties were investigated by using luminescence spectroscope, the results show that all the six complexes of terbium exhibit excellent luminescence, due to the transition from the lowest excited state ^5D4 to ^7F ground state manifold, the complexes of terbium with sulfosalicylic acid have the strongest fluorescence intensity, and is stronger than o-aminobenzoic acid-terbium, whose fluorescence intensity is regarded as the strongest one in the literature, and even stronger than some phosphor of terbium. 相似文献
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研究了316L纤维的长度、直径与含量对HA-ZrO_2(CaO)/316L纤维生物复合材料的力学性能的影响规律.结果表明:纤维直径为40μm的复合材料力学性能优于纤维直径为50μm的复合材料;纤维长度为0.8~1.2mm的复合材料力学性能优于纤维长度为2~3mm的复合材料;随着纤维体积分数增大,纤维之间相互接触而导致在复合材料中形成的微孔增多,并成为微裂纹源,导致材料力学性能下降.含20vol%直径为40μm、长度为0.8~1.2mm的316L纤维的HA-ZrO_2(CaO)/316L纤维生物复合材料的综合力学性能最佳,其抗弯强度、杨氏模量、断裂韧性和相对密度分别为140.1MPa、117.8GPa、5.81MPa·m~(1/2)和87.1%.复合材料微观组织随HA粉末和316L纤维成分的变化呈规律性变化,没有出现明显的裂纹或孔隙,316L纤维与HA-ZrO_2(CaO)基体紧紧地咬合在一起,其结合主要靠基体对316L纤维的物理附着力所致.基体中发生微量Fe元素扩散,但在316L纤维中不发生基体Ca、P元素的扩散.含5%316L纤维复合材料表现为脆性断裂,而含10%、20%、40%316L纤维复合材料均表现为韧性断裂,且韧性程度随316L纤维含量的增加而增大. 相似文献
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The viscoelastic properties of the suspension of monodisperse spherical silica produced by hydrolysis of tetraethoxysilane in alcohol solvent with ammonia as a catalyst in polyethylene glycol (PEG) were studied. The results show that the SiO2/PEG suspension possesses the reversible shear thinning and shear thickening behaviors. In the shear thinning region, the loss modulus (G″) almost remains unchanged, whereas the storage modulus (G′) decreases. In the shear thickening region, G″ and G′ increase for the formation of the "clusters". The larger G″ over G′ in all the stress studied shows that the system mainly possesses the viscous property, and that the energy dissipated(Ed) is larger than that stored. Ed of this suspension is proportional to the maximum strain (γmax) rising with the exponent of 1.92 under low shear stress; however, in the shear thickening region, Ed is proportional to γmax rising with the exponent of 5.00. 相似文献