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581.
582.
湖泊沉积物中邻苯二甲酸酯类的GC/MS分析 总被引:7,自引:1,他引:7
东湖沉积物阴干后用二氯甲烷溶剂萃取,用DB-5弹性石英毛细管柱GC/MS分离鉴定,并结合m/z149质量色谱图,确证东湖沉积物中含有9种邻苯二甲酸酯类化合物,它们是邻苯二甲酸二乙酯、二异丁酯、二正丁酯、二己酯、己基辛基酯、二-(2-乙基己基)酯、二辛酯、己基癸基酯和辛基癸基酯,其特征离子及峰度见表1。 相似文献
583.
硅相增强锌铝基复合材料中团球硅晶体的形成 总被引:3,自引:0,他引:3
本文研究了硅相增强锌铝基复合材料(ZA27SiX及ZA35SiX)中,硅晶体形态在钠作用下的变化,发现钠元素可使锌铝合金中的块状初生硅晶体变成球团状,共晶硅晶体能在球团硅晶体上辐射生长、成簇长大.对球硅晶体的形成机理进行了探讨. 相似文献
584.
按照GB/T 6739.6规定,采用F检验法比较了5种铜磁铁矿中铜含量分析方法的精密度,得出了5种分析方法精密度显著性差异情况,给出了选择分析方法的原则。 相似文献
585.
Nonlinear Dynamics - The paper treats stationary response of a stochastically excited multi-degree-of-freedom (multi-DOF) vibro-impact system undergoing Markovian jump. The vibro-impact system with... 相似文献
586.
Greatly enhanced thermo‐oxidative stability of polybenzoxazine thermoset by incorporation of m‐carborane
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Xin Huang Qiuhong Zhang Zheng Meng Jiangjiang Gu Xudong Jia Kai Xi 《Journal of polymer science. Part A, Polymer chemistry》2015,53(8):973-980
Novel polybenzoxazine precursor containing m‐carborane unit in the main‐chain has been firstly synthesized through click reaction of diazidomethyl m‐carborane (DAMC) and diacetylene bisbenzoxazine (DABB). Meanwhlie, the traditional polybenzoxazine precursor was also prepared through click reaction of diazidomethyl p‐benzene (DAPB) and DABB as a control. 1H NMR was used to confirm the structures of the monomers and the resulting polymers. FT‐IR and differential scanning calorimetry (DSC) were used to study the curing behavior of carborane‐containing benzoxazine polymer (CCBP). Dynamic mechanical analysis (DMA) study demonstrated that the cured CCBP had high storage moduli and high Tg. Thermogravimetric analysis (TGA) and ablation test showed that the cured CCBP had outstanding thermo‐oxidative stability. During thermal ablation of cured CCBP, organic material was degraded, and a passivation layer with oxidized m‐carboranes was formed, which prevented the underlying polymer from further degradation. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 973–980 相似文献
587.
Gas hydrate (GH) dissociates owing to thermal injection or pressure reduction from the well in gas/oil or GH exploitation. GH dissociation leads to, for exam-ple, decreases in soil strength, engineering failures such as wellbore instabilities, and marine landslides. The FLAC3D software was used to analyze the deformation of the soil stratum and vertical wells with GH dissociation. The effects of Young’s modulus, internal friction angle, cohesion of the GH layer after dissociation, and the thickness of the GH layer on the deformation of soils were studied. It is shown that the maximum displacement in the whole soil stratum occurs at the interface between the GH layer and the over-layer. The deformation of the soil stratum and wells increases with decreases in the modulus, internal friction angle, and cohesion after GH dissociation. The increase in thickness of the GH layer enlarges the deformation of the soil stratum and wells with GH dissociation. The hydrostatic pressure increases the settlement of the soil stratum, while constrain-ing horizontal displacement. The interaction between two wells becomes significant when the affected zone around each well exceeds half the length of the GH dissociation zone. 相似文献
588.
Dingshan Yu Yujie Chen Baojun Li Fuli Zhao Cairong Ding Xudong Chen 《Applied Physics A: Materials Science & Processing》2011,103(2):329-334
We have demonstrated catalyst-free fabrication of multi-branched ZnO nanorods and their interesting optical properties. Under
Xe lamp excitation (325 nm), it is found that the ethanol rinsing leads to an obviously enhanced ultraviolet emission at room
temperature. Moreover, temperature-dependent emission spectra exhibit an anomalous temperature dependence of the ultraviolet
emission intensity. This has been analyzed in terms of the competition between the radiative and nonradiative hopping processes
using a model developed for disordered porous semiconductors. With femtosecond pulse excitation (640 nm), two-photon-induced
photoluminescence is observed, which is confirmed by the quadratic dependence of the emission intensity on the excitation
pulse energy. 相似文献
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