The VO2 powders were prepared by hydrothermal synthesis.The effects of heat treatment conditions and Y-doping on the structure and phase transition temperature of VO2 were studied.The XRD,SEM and TEM results show that...The VO2 powders were prepared by hydrothermal synthesis.The effects of heat treatment conditions and Y-doping on the structure and phase transition temperature of VO2 were studied.The XRD,SEM and TEM results show that the heat treatment temperature has a significant effect on the crystal transformation of VO2 precursor.Increasing temperature is conducive to the transformation of precursor VO2(B)to ultrafine VO2(M).The Y-doping affects the structure of VO2.Y^3+can occupy the lattice position of V4+to form YVO4 solid solution,which can increase the cell parameters of VO2.Due to the lattice deformation caused by Y-doping,the aggregation of particles is prevented,and the grain is refined obviously.DSC curves show that Y-doping can reduce the phase transition temperature of VO2(M).After adding 9 at.%Y,the phase transition temperature can be reduced from 68.3 to 61.3℃.展开更多
Harvested fruits of mango （Mangifera indica） suffer from both physiological and pathological deterioration in quality during storage which consequently affects their market value. A study was conducted to investigat...Harvested fruits of mango （Mangifera indica） suffer from both physiological and pathological deterioration in quality during storage which consequently affects their market value. A study was conducted to investigate the effects of fungicide treatments and storage temperatures on fruit quality of two mango cultivars, Keirt and Palmer. Mango fruits were treated with 0.04% or 0.08% v/v Triadimefon at either 53 ℃ （hot） or at room temperature and then either stored under ambient conditions （27-29 ℃） or in a refrigerator at a temperature of 11-12 ℃. Fruits stored under ambient conditions developed external colour faster than those stored at a lower temperature. Brix values for fruits treated with Triadimefon decreased with time. Fruits stored at lower temperatures gave least Brix values as compared with those stored under ambient conditions. Percentage titratable acid （%TA） of fruits stored at low temperatures increased over time. Fruits stored at lower temperatures recorded lower pH compared with fruits stored under ambient conditions. Palmer fruits recorded higher %Brix to %TA ratio, indicating a higher sweetness level. The firmness of Palmer fruits kept at lower temperatures increased with time when compared with Keitt fruit. Fruits treated with hot water at 53 ℃ and/or stored at low temperatures （11-12 ℃） had lower levels of anthracnose infection than other treatments. Keitt fruits were more susceptible to anthracnose infection than Palmer fruits. Mango fruits should therefore be treated with hot water at 53 ℃ and then stored at low temperatures （11-12 ℃） in order to slow down the rate of ripening and to reduce anthracnose infection.展开更多
A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste （MOSW）. Heating failure was simulated by decreasi...A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste （MOSW）. Heating failure was simulated by decreasing temperature suddenly from 55 ℃ to 20 ℃ suddenly, 2 h time is needed for temperature decrease and recovery. Under the conditions of 8.0 g/（L·d） and 15 d respectively for MOSW load and retention time, following results were noted： （1） biogas production almost stopped and VFA （volatile fatty acid） accumulated rapidly, accompanied by pH decrease; （2） with low temperature （20 ℃） duration of 1, 5, 12 and 24 h, it took 3, 11, 56 and 72 h for the thermophilic anaerobic digestion system to reproduce methane after temperature fluctuation, （3） the longer the low temperature interval lasted, the more the methanogenic bacteria would decay, hydrolysis, acidification and methanogenesis were all influenced by temperature fluctuation： （4） the thermophilic microorganisms were highly resilient to temperature fluctuation.展开更多
基金Projects(51404183,51504177)supported by the National Natural Science Foundation of China。
文摘The VO2 powders were prepared by hydrothermal synthesis.The effects of heat treatment conditions and Y-doping on the structure and phase transition temperature of VO2 were studied.The XRD,SEM and TEM results show that the heat treatment temperature has a significant effect on the crystal transformation of VO2 precursor.Increasing temperature is conducive to the transformation of precursor VO2(B)to ultrafine VO2(M).The Y-doping affects the structure of VO2.Y^3+can occupy the lattice position of V4+to form YVO4 solid solution,which can increase the cell parameters of VO2.Due to the lattice deformation caused by Y-doping,the aggregation of particles is prevented,and the grain is refined obviously.DSC curves show that Y-doping can reduce the phase transition temperature of VO2(M).After adding 9 at.%Y,the phase transition temperature can be reduced from 68.3 to 61.3℃.
文摘Harvested fruits of mango （Mangifera indica） suffer from both physiological and pathological deterioration in quality during storage which consequently affects their market value. A study was conducted to investigate the effects of fungicide treatments and storage temperatures on fruit quality of two mango cultivars, Keirt and Palmer. Mango fruits were treated with 0.04% or 0.08% v/v Triadimefon at either 53 ℃ （hot） or at room temperature and then either stored under ambient conditions （27-29 ℃） or in a refrigerator at a temperature of 11-12 ℃. Fruits stored under ambient conditions developed external colour faster than those stored at a lower temperature. Brix values for fruits treated with Triadimefon decreased with time. Fruits stored at lower temperatures gave least Brix values as compared with those stored under ambient conditions. Percentage titratable acid （%TA） of fruits stored at low temperatures increased over time. Fruits stored at lower temperatures recorded lower pH compared with fruits stored under ambient conditions. Palmer fruits recorded higher %Brix to %TA ratio, indicating a higher sweetness level. The firmness of Palmer fruits kept at lower temperatures increased with time when compared with Keitt fruit. Fruits treated with hot water at 53 ℃ and/or stored at low temperatures （11-12 ℃） had lower levels of anthracnose infection than other treatments. Keitt fruits were more susceptible to anthracnose infection than Palmer fruits. Mango fruits should therefore be treated with hot water at 53 ℃ and then stored at low temperatures （11-12 ℃） in order to slow down the rate of ripening and to reduce anthracnose infection.
基金Project (No. 2002-548) supported by the National Development andReform Commission of China
文摘A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste （MOSW）. Heating failure was simulated by decreasing temperature suddenly from 55 ℃ to 20 ℃ suddenly, 2 h time is needed for temperature decrease and recovery. Under the conditions of 8.0 g/（L·d） and 15 d respectively for MOSW load and retention time, following results were noted： （1） biogas production almost stopped and VFA （volatile fatty acid） accumulated rapidly, accompanied by pH decrease; （2） with low temperature （20 ℃） duration of 1, 5, 12 and 24 h, it took 3, 11, 56 and 72 h for the thermophilic anaerobic digestion system to reproduce methane after temperature fluctuation, （3） the longer the low temperature interval lasted, the more the methanogenic bacteria would decay, hydrolysis, acidification and methanogenesis were all influenced by temperature fluctuation： （4） the thermophilic microorganisms were highly resilient to temperature fluctuation.
