http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Pei Chen,Haipei Bie,Rushan Bie 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.9
Fundamental studies on the removal of metal impurities are essential for the production of nanosilica by combustion. This study reports the leaching characteristics, leaching kinetics and occurrence form of the metal impurities present in rice husk based on acid pretreatment. Acid pretreatment removes most of the metal impurities present in rice husk. In particular, 98wt% removal of potassium can be reached. The acid concentration, leaching time and reagent type have significant effects on the leaching of metal impurities, and optimal conditions exist for the acid pretreatment process. Furthermore, the leaching of metal impurities occurs through two stages, and parts of the metal impurities exist in organic-bound form, which can be leached through ion exchange. The results show that the pseudosecond- order model is suitable for describing the leaching kinetics of the metal impurities present in rice husk, and empirical formulas for predicting the metal contents leached from rice husk during acid pretreatment at ambient temperature are also obtained. Additionally, the different occurrence form and quantities of metal impurities in rice husk lead to different leaching effects, which strongly influences the chemical properties and quality of the obtained silica particles.
Chao Su,Liu Liu,Haipei Liu,Brett J. Ferguson,Yanmin Zou,Yankun Zhao,Tao Wang,Youning Wang,Xia Li 한국식물학회 2016 Journal of Plant Biology Vol.59 No.3
The accumulation and redistribution of the plant hormone auxin plays a crucial role in root development and patterning. Plants can alter their root system architecture (RSA) to adapt to different biotic and abiotic stresses. In addition, reactive oxygen species (ROS), such as H2O2, are known to increase in plants undergoing stress. Here, we present evidence that H2O2 can regulate auxin accumulation and redistribution through modulating polar auxin transport, leading to changes in RSA. Plants exposed to different concentrations of H2O2 formed a highly branched root system with abundant lateral roots and a shorter primary root. Monitoring of the auxin responsive DR5::GUS indicated that auxin accumulation decreased in lateral root primordia (LRP) and emerging lateral root tips. In addition, polar auxin transport, including both basipetal and acropetal transport modulated by AUX1 and PIN protein carriers, was involved in the process. Taken together, our results suggest that H2O2 could regulate plastic RSA by perturbing polar auxin transport as a means of modulating the accumulation and distribution of auxin.