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The Zhangjiakou-Xuanhua area is a mineral resource-concentrated area for gold-silver polymetallic ore deposits. The temporal and spatial distribution and origin of mineral resources have been argued for a long time. Based on the comprehensive studies of geochronology and sulfur, lead, oxygen, carbon and noble gas isotopes, it is considered that the temporal and spatial distribution of mineral resources in this area is obviously controlled by the Zhangjiakou-Xuanhua mantle branch structure, as is reflected by the occurrence of gold deposits in the inner parts and of Ag-Pb-Zn polymetallic ore deposits in the outer parts. The mineralization took place mainly during the Yanshanian period. Ore-forming materials came largely from the deep interior of the Earth, and hydrothermal fluids were derived predominantly from Yanshanian magmatism.

Study on the intermediary species of theophylline oxidation process is very important for understanding its pharmacological action. Theophylline is a drug commonly used in treatment of asthma. In our study, we found that a red intermediate which appeared and then disappeared immediately after we mixed Ce(IV) with theophylline. We have investigated this intermediate via rapid-scanning stopped-flow W/Visible spectroscopy combined with single wavelength stopped-flow technique. Successive reaction kinetic simulation model has been used to study properties of the intermediate. A possible reaction mechanism is proposed.