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61.
《Journal of Experimental Nanoscience》2013,8(5):383-389
A facile strategy to graft polymers onto the surfaces of multiwalled carbon nanotubes (MWCNTs) was developed via the free radical addition process in the solution radical polymerisation of styrene in presence of the MWCNTs without any pretreatment so that the length of the original MWCNTs remained unchanged. The polystyrene grafted MWCNTs were characterised with Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis (TGA) and transmission electron microscopy techniques. The effect of the amount of the initiator added and of the polymerising temperature on the percentage of grafting (PG%) and conversion of monomer (C%) were calculated from the TGA results. It was found that the maximum PG% of 15.6% was achieved with 0.5% initiator added and the higher polymerising temperature favoured the grafting polymerisation. The proposed method is expected to be extended to other vinyl monomers and offers another diverse way for the sidewall functionalisation of MWCNT. 相似文献
62.
Long‐term addition of micro‐amounts of hydrazine enhances nitrogen removal and reduces NO and NO3− production in a SBR performing Anammox 下载免费PDF全文
63.
64.
The morphology and textural characteristics of silica products formed via the hydrolysis and condensation of tetraethyl orthosilicate in increasing diluted dodecylamine solutions have been investigated. The results show that the pH values of the synthesis media increase with the initial additions of water. The formation of silica speeds up as the solution is diluted. As a result, microporous silica microspheres with increasing surface areas, pore volumes, pore and particle sizes are formed by a monomer addition mechanism. Further increases in the amount of water result in the decrease of the concentrations of OH?. Consequently, the formed silica seeds become less active and the diffusion of silica species is accelerated. The monomer addition process thus becomes difficult. The self-nucleation of silica species leads to the formation of large quantities of primary silica nano particles. In order to minimise the internal energy of the reaction system, the nanoparticles aggregate to form micrometre-sized silica microspheres with a relatively loose structure. The synthesised microspheres can be used in the removal of organic pollutants in water. It is shown that the nanoporous silica microspheres formed by the aggregation mechanism have a faster dye adsorption rate and a higher adsorption capacity than those formed by the monomer addition mechanism. 相似文献
65.
Ashraf A. Aly Tamer El Malah Esam A. Ishak Stefan Bräse 《Journal of Sulfur Chemistry》2016,37(2):141-147
Dithiacarbamates reacted with malononitrile dimer to give 1,4-dihydropyridine-2-thiols. The structures of the obtained products were proven by IR, mass, and NMR spectra and elemental analyses. The reaction mechanism is also discussed. 相似文献
66.
Mg–3Al–1Zn–2Ca (AZX312) alloy has been forged in the temperature range of 350–500 °C and at speeds in the range of 0.01–10 mm s−1 to produce a rib-web shape with a view to validate the processing map and study the microstructural development. The process was simulated through finite-element method to estimate the local and average strain rate ranges in the forging envelope. The processing map exhibited two domains in the following ranges: (1) 350–450 °C/0.0003–0.05 s−1 and (2) 450–500 °C/0.03–0.7 s−1 and these represent dynamic recrystallization (DRX) and intercrystalline cracking, respectively. The optimal workability condition according to the processing map is 425–450 °C/0.001–0.01 s−1. A wide flow instability regime occurred at higher strain rates diagonally across the map, which caused flow localization that should be avoided in forming this alloy. The experimental load–stroke curves correlated well with the simulated ones and the observed microstructural features in the forged components matched with the ones predicted by the processing map. 相似文献
67.
N.A.A. Elkanzi Nesrin M. Morsy Tamer El Malah Ahmed M. Shawky 《Journal of Sulfur Chemistry》2016,37(1):114-121
The reactions of thiocarbohydrazones with malononitrile dimer under microwave irradiation are reported. These reactions give 6-imino-1,3,4-thiadiazines in good yields. The structures of products were elucidated by MS, IR and NMR spectra together with elemental analyses. The reaction mechanism was discussed. 相似文献
68.
The segregation process as applied to nickel laterite ores involves the formation of gaseous nickel and iron chlorides which are subsequently reduced to form ferronickel on the surface of a solid carbon reductant. A fundamental study of the process has been carried out using limonite, nontronite and garnierite ores. The study highlighted the significant impacts that ore mineralogy and carbon addition have on the amount of nickel which is segregated rather than retained within the ore due to in situ reduction. These important aspects affecting nickel recovery and the success of the process are discussed in this paper. 相似文献
69.
Joao Henrique da Silva Rego ;Antonio Alberto Nepomucenol ;Enio Pazini Figueiredo ;Nicole Pagan Hasparyk 《土木工程与建筑:英文版》2014,(11):1396-1402
In several countries, the residual RHA (rice husk ash) has been produced in rice processing industries or in thermoelectric plants that use rice husk to generate heat and/or electrical energy, usually without burning process control. This causes a reduction in the amorphous silica content of residual RHA, which distinguishes them from the RHA produced according to controlled burning process, which is totally amorphous and considered a highly reactive pozzolan. In this paper, the hydration products and the porous structure of binders paste were studied by replacing, in weight of 5%, 10% and 20% of Portland cement OPC (ordinary Portland cement), by residual RHAs named A and B, which have high and low content of amorphous silica, respectively, using microstructure evaluation techniques as XRD (X-ray diffraction), TG (thermogravimetric) tests and MIP (mercury intrusion porosimetry). A reducing the size of the pores of the pastes was observed according to the increase of content replacement of RHA A and RHA B. 相似文献
70.
Ying ying Zong Ying chun Liang Zhong wei Yin De bin Shan 《International Journal of Hydrogen Energy》2012
The true stress-strain curves of TC21 titanium alloy charged with up to 0.7 wt.% hydrogen were obtained by the isothermal hot compression tests which were carried out on an Instron 5500 machine at 1023 to 1223 K and 0.001 to 0.1 s−1. The dependence of the steady state flow stress on hydrogen content was determined. The results showed that with the increase of hydrogen content flow stress decreased at lower hydrogen content and then increased at higher hydrogen content. Suitable hydrogen addition can significantly decrease the flow stress and improve the hot workability of TC21 titanium alloy. The flow stress behaviors and the dependence of hydrogen content on flow stress were clarified by microstructural observation. The optimum hydrogen content at different deformation temperature was determined. 相似文献