The availability of liquid chromatography ultraviolet nuclear magnetic resonance mass spectrometry (LC UV NMR MS)integrated systems is providing greater information content and confidence for a variety of sample types...The availability of liquid chromatography ultraviolet nuclear magnetic resonance mass spectrometry (LC UV NMR MS)integrated systems is providing greater information content and confidence for a variety of sample types, such asdrug metabolites, natural products, impurities, and degradants. A wide range of experimental strategies can be pur sued,highlighting the flexibility and performance possible with this multihyphenated technique.展开更多
On account of excellent thermal physical properties, molten nitrates/nitrites salt has been widely employed in heat transfer and thermal storage industry, especially in concentrated solar power system. The thermal sta...On account of excellent thermal physical properties, molten nitrates/nitrites salt has been widely employed in heat transfer and thermal storage industry, especially in concentrated solar power system. The thermal stability study of molten nitrate/nitrite salt is of great importance for this system, and the decomposition mechanism is the most complicated part of it. The oxide species O2^2- and O2^- were considered as intermediates in molten KNO3-NaNO3 while hard to been detected in high temperature molten salt due to their trace concentration and low stability. In this work, the homemade in situ high temperature UV- Vis instrument and a commercial electron paramagnetic resonance were utilized to supply evidence for the formation of superoxide during a slow decomposition process of heat transfer salt （HTS, 53 wt% KNO3/40 wt% NaNO2/7 wt% NaNO3）. It is found that the superoxide is more easily generated from molten NaNO2 compared to NaNO3, and it has an absorption band at 420-440 nm in HTS which red shifts as temperature increases. The band is assigned to charge-transfer transition in NaO2 or KO2, responsible for the yellow color of the molten nitrate/nitrite salt. Furthermore, the UV absorption bands of molten NaNO2 and NANO3 are also obtained and compared with that of HTS.展开更多
The reaction of VCl3 with 4-（2, 4-dihydroxybenzaldimine） antipyrine （LH） in a l ： 1 molar ratio results in formation of the general complex of [VOL（CI）OH]. The nature of bonding and stereochemistry of the compl...The reaction of VCl3 with 4-（2, 4-dihydroxybenzaldimine） antipyrine （LH） in a l ： 1 molar ratio results in formation of the general complex of [VOL（CI）OH]. The nature of bonding and stereochemistry of the complex was deduced from the elemental analysis, IR, UV-Vis, 1H and ^13C NMR spectroscopy. This complex has a coordination number five （square pyramidal） as known for many vanadyl complexes. The formation of the vanadyl ion （VO^2＋） and the mode of bonding of the Schiff base through the oxygen of the pyrazol ring and the nitrogen of the azomethine group to the vanadyl ion were established by IR technique.展开更多
Three different nanorod-like gallium oxides with mono/poly-crystalline nature(α, β, and α/β-Ga2O3) were prepared by regulating the amount of polyethylene glycol(PEG) 6000 in the range of 0.2–0.8 g proportionally ...Three different nanorod-like gallium oxides with mono/poly-crystalline nature(α, β, and α/β-Ga2O3) were prepared by regulating the amount of polyethylene glycol(PEG) 6000 in the range of 0.2–0.8 g proportionally via a hydrothermal method combined with further calcination. The bandgap of the products, given by UV-Vis diffuse reflectance spectra(UV-Vis DRS), was in the order of α-Ga2O3 > α/β-Ga2O3 > β-Ga2O3. To further investigate the photocatalysis performance of the catalysts, the decomposition of rhodamine B(Rh B) by Ga2O3 under UV light illumination(λ < 387 nm) was presented and complete degradation could be achieved within 30 min, a result that showed the highest efficiency. The photocatalytic oxidation mechanism is further discussed and prominently related to the active species: hydroxyl radical(·OH) and superoxide radical(O·-2), which were confirmed by electron paramagnetic resonance(EPR).展开更多
文摘The availability of liquid chromatography ultraviolet nuclear magnetic resonance mass spectrometry (LC UV NMR MS)integrated systems is providing greater information content and confidence for a variety of sample types, such asdrug metabolites, natural products, impurities, and degradants. A wide range of experimental strategies can be pur sued,highlighting the flexibility and performance possible with this multihyphenated technique.
基金The Programme Strategic Scientific Alliances between China and the Netherlands(2008DFB50130)National Basic Research Program of China (2009CB623503,2005CB221407)
基金This work was supported by the ＂Strategic Priority Research Program, TMSR＂ of the Chinese Academy of Sciences （No.XD02002400）, the National Natural Science Foundation of China （No.51506214）, the Hundred Talents Program, CAS and Shanghai Pujiang Program.
文摘On account of excellent thermal physical properties, molten nitrates/nitrites salt has been widely employed in heat transfer and thermal storage industry, especially in concentrated solar power system. The thermal stability study of molten nitrate/nitrite salt is of great importance for this system, and the decomposition mechanism is the most complicated part of it. The oxide species O2^2- and O2^- were considered as intermediates in molten KNO3-NaNO3 while hard to been detected in high temperature molten salt due to their trace concentration and low stability. In this work, the homemade in situ high temperature UV- Vis instrument and a commercial electron paramagnetic resonance were utilized to supply evidence for the formation of superoxide during a slow decomposition process of heat transfer salt （HTS, 53 wt% KNO3/40 wt% NaNO2/7 wt% NaNO3）. It is found that the superoxide is more easily generated from molten NaNO2 compared to NaNO3, and it has an absorption band at 420-440 nm in HTS which red shifts as temperature increases. The band is assigned to charge-transfer transition in NaO2 or KO2, responsible for the yellow color of the molten nitrate/nitrite salt. Furthermore, the UV absorption bands of molten NaNO2 and NANO3 are also obtained and compared with that of HTS.
文摘The reaction of VCl3 with 4-（2, 4-dihydroxybenzaldimine） antipyrine （LH） in a l ： 1 molar ratio results in formation of the general complex of [VOL（CI）OH]. The nature of bonding and stereochemistry of the complex was deduced from the elemental analysis, IR, UV-Vis, 1H and ^13C NMR spectroscopy. This complex has a coordination number five （square pyramidal） as known for many vanadyl complexes. The formation of the vanadyl ion （VO^2＋） and the mode of bonding of the Schiff base through the oxygen of the pyrazol ring and the nitrogen of the azomethine group to the vanadyl ion were established by IR technique.
基金funded by the National Natural Science Foundation of China(21377067,21177072,and 21207079)the Natural Science Foundation for the Innovation Group of Hubei Province,China(2009CDA020)
文摘Three different nanorod-like gallium oxides with mono/poly-crystalline nature(α, β, and α/β-Ga2O3) were prepared by regulating the amount of polyethylene glycol(PEG) 6000 in the range of 0.2–0.8 g proportionally via a hydrothermal method combined with further calcination. The bandgap of the products, given by UV-Vis diffuse reflectance spectra(UV-Vis DRS), was in the order of α-Ga2O3 > α/β-Ga2O3 > β-Ga2O3. To further investigate the photocatalysis performance of the catalysts, the decomposition of rhodamine B(Rh B) by Ga2O3 under UV light illumination(λ < 387 nm) was presented and complete degradation could be achieved within 30 min, a result that showed the highest efficiency. The photocatalytic oxidation mechanism is further discussed and prominently related to the active species: hydroxyl radical(·OH) and superoxide radical(O·-2), which were confirmed by electron paramagnetic resonance(EPR).
