Synthesis of novel MnO_x@TiO_2 core-shell nanorod catalyst for low-temperature NH_3-selective catalytic reduction of NOx with enhanced SO_2 tolerance

In this study,a MnOx@TiO2 core‐shell catalyst prepared by a two‐step method was used for the low‐temperature selective catalytic reduction of NOx with NH3.The catalyst exhibits high activity,high stability,and excellent N2 selectivity.Furthermore,it displays better SO2 and H2O tolerance than its MnOx,TiO2,and MnOx/TiO2 counterparts.The prepared catalyst was characterized systematically by transmission electron microscopy,high‐resolution transmission electron microscopy,X‐ray diffraction,Raman,BET,X‐ray photoelectron spectroscopy,NH3 temperature‐programmed desorption and H2 temperature‐programmed reduction analyses.The optimized MnOx@TiO2 catalyst exhibits an obvious core‐shell structure,where the TiO2 shell is evenly distributed over the MnOx nanorod core.The catalyst also presents abundant mesopores,Lewis‐acid sites,and high redox capability,all of which enhance its catalytic performance.According to the XPS results,the decrease in the number of Mn4+active centers after SO2 poisoning is significantly lower in MnOx@TiO2 than in MnOx/TiO2.The core‐shell structure is hence able to protect the catalytic active sites from H2O and SO2 poisoning.

Construction of databases:advances and significance in clinical research

Widely used in clinical research, the database is a new type of data management automation technology and the most efficient tool for data management. In this article, we first explain some basic concepts, such as the definition, classification, and establishment of databases. Afterward, the workflow for establishing databases, inputting data, verifying data, and managing databases is presented. Meanwhile, by discussing the application of databases in clinical research, we illuminate the important role of databases in clinical research practice. Lastly, we introduce the reanalysis of randomized controlled trials(RCTs) and cloud computing techniques, showing the most recent advancements of databases in clinical research.

Effect of Several Common Processing Methods on Content Changes of Resistant Starch and Main Nutrients in ‘Luotian Chestnut’

Using ＇Luotian chestnut＇ as the raw material, the content changes of resistant starch and main nutrients in the processed fruit were studied after taken common processing of high-temperature steaming of canned food, sand-mixed frying and cooking without shells, with the aim to find out the effects of different processing methods on the content changes of nutrients in chestnuts. The result showed that there were significant differences in the resistant starch contents by different processing methods. After processing, the retention degree of resistant starch was the lowest using the methods of sand-mixed frying, of 42.42%, while the highest was found in canned chestnut products, of 93.16%. Among the main nutrients, adding water and sugar would reduce content of resistant starch, while increasing the protein content would promote the retention of resistant starch retention. The changes in lipid content had no effect or not a single promoting or weakening effects on the content of resistant starch.

Novel CeO_2@TiO_2 core–shell nanostructure catalyst for selective catalytic reduction of NOx with NH_3

The CeO2@TiO2 core-shell nanostructure catalyst prepared by a two-step hydrothermal method was used for selective catalytic reduction （SCR） of NOx with NH3 in this study. The catalyst presented the obvious core-shell structure, and the shell was amorphous TiO2 which could protect the active center from the SO2 erosion. The catalyst showed high activity and stability, excellent N2 selectivity and superior SO2 resistance and H2O tolerance. Characterizations such as TEM, HR-TEM, XRD, BET, XPS, NH3-TPD, and H2-TPR were carried out. The results indicated that the catalyst had large surface area and the active sites were well dispersed on the surface. The NH3-TPD, H2-TPR and XPS results implied that its increased SCR activity might be due to the enhancement of NH3 chemisorption and the increase of active oxygen species, both of which were conductive to NH3 activation. The excellent catalytic performance suggests that it is a promising candidate for SCR catalyst.