Improvement of the fluidity and setting time of grouting materials has been recognized as an effective approach of seepage prevention in foundation works, and it is quite common to be used for handling severe leakages...Improvement of the fluidity and setting time of grouting materials has been recognized as an effective approach of seepage prevention in foundation works, and it is quite common to be used for handling severe leakages in complex ground conditions, such as loose, broken and fully fissured stratum. For the purposed of better meeting the engineering requirements, experimental studies were conducted in this study with focus on the nanocomposite grouting materials and the related controlled grouting technology. As compared with the commonly used silicate-sulpho-aluminate composite cement, which is characterized by relatively poor rheological property, quick setting time and low strength, the most suitable nano-material with proper reactants were selected intentionally to improve the mentioned attributes of composite cement. Due to the setting time and strength of the targeted cement slurry behaving with poor performance of harmonization to engineering construction problems, hydration synergistic effect of these composites were investigated in our experiments. Results showed that the properties of grouting materials, including initial fluidity, setting time, ideal right-angle thickening, and early strength and late strength were sufficient to produce an expected grouting application. It is therefore advocated that the refined grouting material could provide a better solution to fix grouting problems in complex ground cementing operations.展开更多
9-Fluorenylidenemalononitrile (FDCN) or 1,1 diphenyl 2,2 dicyanoethylene (DPCN) reacted with 10 methyl 9,10 dihydroacridine (AcrH 2) under irradiation ( λ >320 nm) to give couping products. In order t...9-Fluorenylidenemalononitrile (FDCN) or 1,1 diphenyl 2,2 dicyanoethylene (DPCN) reacted with 10 methyl 9,10 dihydroacridine (AcrH 2) under irradiation ( λ >320 nm) to give couping products. In order to gain further insight into the mechanism of the photo induced reaction, the photophysics of the reactions of FDCN or DPCN with AcrH 2 have been investigated by using UV vis spectroscopy, fluorescence spectroscopy, excitation spectroscopy and time resolved fluorescence spectroscopy, respectively. The results show that FDCN or DPCN interacts with AcrH 2 in the ground states to form a charge transfer complex, which further reacts to give the coupling product upon irradiation.展开更多
基金funded by National Natural Science of China (Grant Nos.41672362)Key Projects of Sichuan Provincial Department of Education (Grant No.16ZA0099)the State Key Laboratory of Geohazard Prevention & Geoenvironment Protection (Grant No.SKLGP2017Z011)
文摘Improvement of the fluidity and setting time of grouting materials has been recognized as an effective approach of seepage prevention in foundation works, and it is quite common to be used for handling severe leakages in complex ground conditions, such as loose, broken and fully fissured stratum. For the purposed of better meeting the engineering requirements, experimental studies were conducted in this study with focus on the nanocomposite grouting materials and the related controlled grouting technology. As compared with the commonly used silicate-sulpho-aluminate composite cement, which is characterized by relatively poor rheological property, quick setting time and low strength, the most suitable nano-material with proper reactants were selected intentionally to improve the mentioned attributes of composite cement. Due to the setting time and strength of the targeted cement slurry behaving with poor performance of harmonization to engineering construction problems, hydration synergistic effect of these composites were investigated in our experiments. Results showed that the properties of grouting materials, including initial fluidity, setting time, ideal right-angle thickening, and early strength and late strength were sufficient to produce an expected grouting application. It is therefore advocated that the refined grouting material could provide a better solution to fix grouting problems in complex ground cementing operations.
文摘9-Fluorenylidenemalononitrile (FDCN) or 1,1 diphenyl 2,2 dicyanoethylene (DPCN) reacted with 10 methyl 9,10 dihydroacridine (AcrH 2) under irradiation ( λ >320 nm) to give couping products. In order to gain further insight into the mechanism of the photo induced reaction, the photophysics of the reactions of FDCN or DPCN with AcrH 2 have been investigated by using UV vis spectroscopy, fluorescence spectroscopy, excitation spectroscopy and time resolved fluorescence spectroscopy, respectively. The results show that FDCN or DPCN interacts with AcrH 2 in the ground states to form a charge transfer complex, which further reacts to give the coupling product upon irradiation.
