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941.
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943.
陶瓷污泥中微量镉催化光度法测定 总被引:1,自引:0,他引:1
利用还原型若丹明B(RRhB)与KClO3的显色反应,对含镉(Ⅱ)陶瓷污泥中痕量镉(Ⅱ)进行测定。结果表明,在pH5.3HAc-NaAc缓冲溶液中具有高灵敏的显色反应,产物的最大吸收波长为560nm,方法的检出限为3.0×10-8gCd2 /L,催化程度与镉(Ⅱ)量在0~0.045mg/L范围内符合比耳定律,加标回收率为97.4%~103.8%(n=6)。结合KI—MIBK萃取分离,满意地测定了陶瓷污泥中的微量镉。 相似文献
944.
陶瓷企业技术创新面临着开发、组织、战略决策风险。影响陶瓷企业技术创新的因素涉及到政治、经济、技术、市场、产品和企业资源等,因此,必须从这些因素出发结合陶瓷企业实际科学的设计并营造出功能完备的能够有效的防范和化解陶瓷企业技术创新风险的预测、评估和控制的组织体系和方法、程序体系。 相似文献
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A lap-shear test was employed to investigate the failure mechanism of a chlorinated polyolefin (CPO) coating on a high-modulus thermoplastic olefin (TPO) substrate fabricated as a blend of a highly crystalline Ziegler-Natta isotactic polypropylene (iPP) and a crystalline metallocene poly(ethylene-butene) (9 wt% butene, EB9) impact modifier. The CPO was a chlorinated polypropylene containing 20 wt% Cl. The results showed that the fracture strength increased with increasing EB9 content in TPO blends. They also showed that the presence of xylene vapor during the bake step improved the adhesion between CPO and iPP itself (by 40%), but had a much smaller effect for the TPOs. Optical and transmission electronic microscopy images revealed a well-defined skin layer approximately 230 μm thick at the mold surface of the injection molded substrates. For the 25 wt% EB9 blend (TPO25), this skin layer consists of thin fibers of EB trapped in a transcrystalline iPP matrix, with crystalline lamellae propagating from the matrix across the EB9 domains. Laser scanning confocal fluorescence microscopy (LCFM) and scanning electron microscopy images of iPP/CPO/iPP samples indicate that failure occurred close to the interface between the CPO and the iPP substrate, and, during fracture, the CPO layer maintained its original thickness. For the TPO/CPO/TPO sandwich samples, the fracture surfaces themselves were much rougher than that between CPO and iPP. Substantial deformation of the CPO layer was seen in the fractured samples, and failure was due primarily to cohesive fracture of the CPO in the region adjacent to the TPO substrate. From the perspective of newly introduced environmental regulations restricting aromatic hydrocarbons in automotive coatings, the most important result was the strong adhesion between CPO and TPO25, with little difference between the samples exposed to xylene vapor and those not exposed to xylene. 相似文献
948.
High molecular weight polyacetylenes bearing nonlinear chromophoric pendants poly[4-ethynyl-4′-(N,N-diethylamino)azobenzene-co-phenylacetylene]s [poly(EAAB-co-PA)s] were synthesized in moderate yields by [Rh(nbd)Cl]2-Et3N. The azo unit in the copolymers can be effectively controlled by the monomer feed ratio. Whereas the homopolymer of EAAB possessed low solubility, all the copolymers, however, dissolved readily in common organic solvents when the poly(EAAB) molar content was less than 41.7%. The structures and properties of the polymers were characterized and evaluated by UV, NMR, optical limiting, and nonlinear optical analyses. All the copolymers possessed high stereoregularity and thermal stability (≥300 °C). They can attenuate intense laser pulses, with solutions of high concentrations showing better performances. The third-order nonlinear susceptibility of the copolymers was as high as 4.62×10−11 esu, which are two orders of magnitude larger than those of poly(PA), and larger than that of poly(N-carbazoylacetylene), and poly(1-naphthylacetylene). 相似文献
949.
The coupling reaction of melt linear low density polyethylene (LLDPE) initiated by dicumyl peroxide (DCP) in steady shear flow field was investigated. The conversion of DCP was measured by electron spin resonance (ESR) and chemical titration. An absolute method was proposed to calculate the actual conversion of DCP from rheological data. The coupling efficiency of DCP was obtained from those analyses, which was shown to increase at first, reach a maximum and then decrease in the end stage. A linear relationship between the coupling efficiency of DCP and the concentration of macroradicals was also found in the experiments. 相似文献
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