Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Más filtros

Bases de datos
Tipo de estudio
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Materials (Basel) ; 16(3)2023 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-36770183

RESUMEN

Dalian Island is located in the sea area near Pingtan County, Fujian, Southeast China. The sea area used to be the junction of the eastern and western ship routes on the Maritime Silk Road, and is also an important region for underwater archaeology in China. This study focused on a sauce-glazed ware of the Song Dynasty, with serious degradation, which was salvaged out of the water at the Dalian Island Wharf. Optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and micro-Raman spectroscopy were used to comprehensively analyze the composition, phase attributes and microstructure of the ware and the surface-attached coagula. The findings revealed that the sea wave-borne debris scoured the surface of the ware, causing mechanical damage to varying degrees and a significant decrease in its degradation resistance. This was the primary factor accounting for the poor preservation state of the salvaged ceramic ware, and the precondition for the subsequent attachment of marine organisms and the deposition of inorganic pollutants. The calcareous skeletons formed on the surface induced by the bio-mineralization of coralline algae (a type of marine plant) could resist the mechanical action caused by the motion of sea waves, thereby slowing down the ware's degradation process. In other words, the calcareous skeletons played a 'bio-protective' role to a certain degree. In addition, inorganic pollutants represented by iron rusts also participated in the corrosion of the glaze. Some pollutants were directly deposited on the pits and cracks on the surface of the ware, which brought stress to the glaze and glaze/body interface, causing the glaze to further crack and spall. Moreover, iron rusts reacted with the glaze, leading to chemical alteration, accompanied by the formation of iron silicate as the alteration product. Anorthite crystals in the interlayer did not participate in the reaction but remained at the original position. The alteration product gradually replaced the original glass phase of the glaze and entered into the body via pores and cracks. In conclusion, the complex degradation morphology of the salvaged sauce-glazed ware could be attributed to the combined action of mechanical damage, marine bio-fouling, and chemical alteration.

2.
Org Lett ; 21(16): 6217-6220, 2019 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-31361144

RESUMEN

Efficient copper-catalyzed aerobic oxidative dearomatization of indoles with trimethylsilyl azide (TMSN3) for the synthesis of 2-azidoindolin-3-ols has been developed. Molecular oxygen served as the oxygen-atom source in this transformation. The multicomponent reaction is appreciated by its high site- and diastereoselectivity, broad substrate scope, and mild conditions at room temperature.

3.
Ying Yong Sheng Tai Xue Bao ; 29(9): 3043-3050, 2018 Sep.
Artículo en Zh | MEDLINE | ID: mdl-30411581

RESUMEN

Identifying and revealing the coupling relationship between urbanization and ecological environment and its forming mechanism, and then putting forward regulation measures, will benefit urban management in making decisions. We examined the coupling process between new-style urbanization and ecological environment system of Fujian Province through the coupling model and coupling-coordination model, and realized the spatial visualization based on the index system of urbanization and ecological environment, in which the index weight was based on the variation coefficient. The results showed that the variation of coupling degree between new-type urbanization and ecological environment system was relatively stable, ranging from 0.77 to 0.99 during 2000 to 2015. There was no obvious difference among the cities except for the Putian in 2000 and Zhangzhou in 2010 were in the break-in stage. The coupling-coordination degree between new-type urbanization and ecological environment system fluctuated around 0.50 during 2000 to 2015 with significant spatial differentiation and shorter evolution time from east to west. The coupling-coordination types of Fujian Province were dominated by the harmonious development type, accompanied by the types of moderate unadjusted recession, moderate coordinated development, and high coordinated development. There was transformation phenomenon among different types. Xiamen was the only one deve-loped into the high coordinated development type in 2015. The city development was mainly featured by lagged urbanization, with the lagged ecological environment in Xiamen in 2010 and in both Fuzhou and Xiamen in 2015.


Asunto(s)
Ambiente , Urbanización , China , Ciudades , Ecosistema
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA