By performing tensile tests in the temperature range of 800°C to 1200°C, the thermoplastic behavior of microalloyed and unmicroalloyed new martensitic low-density steels were investigated, and the mechanism of the effect of Nb and V microalloying on the thermoplasticity was revealed. The results showed that both microalloyed and unmicroalloyed steels have good thermoplasticity and the plasticity increased with increasing deformation temperature. The microalloyed steels above 1000°C could have their high-temperature plasticity significantly enhanced by Nb, V microalloying, while the microalloyed steels at or below 1000°C could have their plasticity reduced. When the deformation temperature exceeds 1000°C, complete recrystallization occurs in both microalloyed and unmicroalloyed steels. The Nb, V microalloys were able to refine the recrystallized grains, which could obtain a stronger resistance to crack expansion and give the microalloyed steels better high-temperature plasticity. When the deformation temperature at or below 1000°C, the unmicroalloyed steel exhibited significant recrystallization. The presence of numerous small-sized NbC precipitation phases, abundant in the microalloyed steel, hindered the recrystallization. This made dynamic recrystallization of microalloyed steels almost non-existent when deformation occurred at lower temperatures, which lead to lower plasticity compared to the unmicroalloyed steel.

Abstract Chemical-looping combustion (CLC), which has the characteristic of greenhouse gas CO2 inherent separation, is a novel combustion technology. In this study, CLC experiments of methane using CaSO4 oxygen carrier with lime addition were carried out in a batched fluidized bed reactor, where the sample was exposed to alternate oxidizing and reducing conditions. The influences of temperature, calcium-to-sulphur ratio and lime particle size on the conversion of CaSO4 and sulfur capture were investigated and a suitable operation condition was determined. Under the optimal operation condition, a multi-cycle test was performed to evaluate the cyclic redox behavior of the lime-promoted CaSO4 sample. X-ray diffraction and a field emission scanning electron microscope were used to characterize the phase and surface morphology of the samples used. The results show that the addition of lime could improve the conversion rate of CaSO4 and the capture efficiency of sulfur-containing gases. The operation conditions of calcium-to-sulfur ratio 0.8, lime particle size of 180-250 μm and operation temperature of 900 °C turned out to be the optimal conditions. Besides, the average desulphurization rate of lime was up to 78.77% during the cyclic test.

Uma série de novos ciclofanos diésteres foi sintetizada por esterificação de cloreto de 1,2 benzenodicarbonilo com oito diferentes dióis sob condições de elevada diluição. As estruturas dos compostos foram verificadas por análise elementar, ressonância magnética nuclear (NMR) de ¹H, espectroscopia IR e espectrometria de massas de alta resolução (HRMS). As estruturas cristalinas de dois dos compostos foram caracterizadas por difratometria de raios X (XRD) de monocristais. Todos os novos ciclofanos foram avaliados com relação a suas atividades biológicas e os resultados mostraram que alguns destes compostos têm baixas atividades antibacterianas e antifúngicas.

A series of novel diester cyclophanes was synthesized by esterification of 1,2-benzenedicarbonyl chloride with eight different diols under high dilution conditions. The structures of the compounds were verified by elemental analysis, ¹H nuclear magnetic resonance (NMR), IR spectroscopy and high resolution mass spectrometry (HRMS). The crystal structures of two compounds were characterized by single crystal X-ray diffractometry (XRD). All the new cyclophanes were evaluated for biological activities and the results showed that some of these compounds have low antibacterial or antifungal activities.