Urbanization brings new selection pressures to wildlife living in cities,and changes in the life-history traits of urban species can reflect their responses to such pressures.To date,most of the studies investigating ...Urbanization brings new selection pressures to wildlife living in cities,and changes in the life-history traits of urban species can reflect their responses to such pressures.To date,most of the studies investigating the impacts of urbanization on avian life-history traits are conducted in Europe and North America,while such studies are often lacking in quickly developing countries in Asia(e.g.,China).In this study,we examined the variations in reproductive life-history traits of Chinese Bulbuls(Pycnonotus sinensis)along the urbanization gradient in Hangzhou,China.We detected 234 natural nests of Chinese Bulbuls and continuously monitored them in two continuous breeding seasons from 2012 to 2013.We collected data on seven life-history traits(laying date,incubation period,nestling period,clutch size,egg volume,hatching success rate,and fledging success rate).We used infrared cameras to record the number of feedings per hour as the measure of food resources for the nestlings.We measured nest predation pressure by monitoring 148 natural breeding nests during breeding seasons and 54 artificial nests immediately after breeding seasons.We then calculated the urbanization synthetic index(USI)as a measure of the level of urbanization and examined its relationship with the seven life-history traits.We found that Chinese Bulbuls laid eggs significantly earlier with increasing USI.However,the other six life-history traits did not vary significantly with the USI.Moreover,the feeding frequency of chicks increased significantly with the USI,but the nest predation pressure of Chinese Bulbuls decreased significantly with the USI.Increased food resources and reduced nest predation pressure in cities may lead to earlier laying date of Chinese Bulbuls.Further study should test whether the earlier laying date of Chinese Bulbuls is the result of phenotypic plasticity or genetic change.展开更多
Synthesis of liquefied petroleum gas (LPG) from synthesis gas using hybrid catalyst consisting of methanol synthesis catalyst and USY or ZSM-5 was investigated in a fixed bed reactor. The composition of the hybrid cat...Synthesis of liquefied petroleum gas (LPG) from synthesis gas using hybrid catalyst consisting of methanol synthesis catalyst and USY or ZSM-5 was investigated in a fixed bed reactor. The composition of the hybrid catalyst had great effect on the activity and selectivity of the catalyst. The effect of reaction temperature (260℃～360℃),GHSV(1500h^-1～9000h^-1)were investigated. The results showed that the best reaction temperature of bifunctional catalyst which consisted of MeLi and ZSM-5 zeolite is 325℃, and the CO conversion achieved 72.28%. The hybrid catalyst, which consisted of ZSM-5 zeolite and methanol synthesis catalyst, demonstrated a highly activity for the formation of light hydrocarbon and the selectivity for C3 and C4 hydrocarbons was 23.90% and 19.06% respectively.展开更多
The Pt-supported USY zeolite catalysts doped with Cr, Al or Zn were prepared by impregnation, and characterized by XRD, low temperature nitrogen physisorption, H2-chemisorption and IR spectroscopy of the pyridine adso...The Pt-supported USY zeolite catalysts doped with Cr, Al or Zn were prepared by impregnation, and characterized by XRD, low temperature nitrogen physisorption, H2-chemisorption and IR spectroscopy of the pyridine adsorption. Catalytic activities were evaluated via the hydroisomerization of n-heptane with an atmospheric fixed-bed reactor. The Pt dispersion and acidity of the Pt-supported USY catalyst were influenced by the addition of the promoters. The Pt-supported catalysts promoted by Cr, Al or Zn, especially by Cr, were catalytically much more stable and exhibited much higher catalytic activity and selectivity for isomerization of n-heptane than the catalysts without the dopant. Both the conversion and selectivity are discussed in relation with the physicochemical properties of catalysts.展开更多
基金supported by the National Natural Science Foundation of China(32271743,31971545,31071908)。
文摘Urbanization brings new selection pressures to wildlife living in cities,and changes in the life-history traits of urban species can reflect their responses to such pressures.To date,most of the studies investigating the impacts of urbanization on avian life-history traits are conducted in Europe and North America,while such studies are often lacking in quickly developing countries in Asia(e.g.,China).In this study,we examined the variations in reproductive life-history traits of Chinese Bulbuls(Pycnonotus sinensis)along the urbanization gradient in Hangzhou,China.We detected 234 natural nests of Chinese Bulbuls and continuously monitored them in two continuous breeding seasons from 2012 to 2013.We collected data on seven life-history traits(laying date,incubation period,nestling period,clutch size,egg volume,hatching success rate,and fledging success rate).We used infrared cameras to record the number of feedings per hour as the measure of food resources for the nestlings.We measured nest predation pressure by monitoring 148 natural breeding nests during breeding seasons and 54 artificial nests immediately after breeding seasons.We then calculated the urbanization synthetic index(USI)as a measure of the level of urbanization and examined its relationship with the seven life-history traits.We found that Chinese Bulbuls laid eggs significantly earlier with increasing USI.However,the other six life-history traits did not vary significantly with the USI.Moreover,the feeding frequency of chicks increased significantly with the USI,but the nest predation pressure of Chinese Bulbuls decreased significantly with the USI.Increased food resources and reduced nest predation pressure in cities may lead to earlier laying date of Chinese Bulbuls.Further study should test whether the earlier laying date of Chinese Bulbuls is the result of phenotypic plasticity or genetic change.
文摘Synthesis of liquefied petroleum gas (LPG) from synthesis gas using hybrid catalyst consisting of methanol synthesis catalyst and USY or ZSM-5 was investigated in a fixed bed reactor. The composition of the hybrid catalyst had great effect on the activity and selectivity of the catalyst. The effect of reaction temperature (260℃～360℃),GHSV(1500h^-1～9000h^-1)were investigated. The results showed that the best reaction temperature of bifunctional catalyst which consisted of MeLi and ZSM-5 zeolite is 325℃, and the CO conversion achieved 72.28%. The hybrid catalyst, which consisted of ZSM-5 zeolite and methanol synthesis catalyst, demonstrated a highly activity for the formation of light hydrocarbon and the selectivity for C3 and C4 hydrocarbons was 23.90% and 19.06% respectively.
文摘The Pt-supported USY zeolite catalysts doped with Cr, Al or Zn were prepared by impregnation, and characterized by XRD, low temperature nitrogen physisorption, H2-chemisorption and IR spectroscopy of the pyridine adsorption. Catalytic activities were evaluated via the hydroisomerization of n-heptane with an atmospheric fixed-bed reactor. The Pt dispersion and acidity of the Pt-supported USY catalyst were influenced by the addition of the promoters. The Pt-supported catalysts promoted by Cr, Al or Zn, especially by Cr, were catalytically much more stable and exhibited much higher catalytic activity and selectivity for isomerization of n-heptane than the catalysts without the dopant. Both the conversion and selectivity are discussed in relation with the physicochemical properties of catalysts.
