Benzyl and anthracenemethyl groups were respectively bonded to the N atoms of 3-aminopropyl functionalized mesoporous SBA-15（APS-SBA-15） to obtain two new base catalysts over which the condensation reaction of benza...Benzyl and anthracenemethyl groups were respectively bonded to the N atoms of 3-aminopropyl functionalized mesoporous SBA-15（APS-SBA-15） to obtain two new base catalysts over which the condensation reaction of benzaldehyde and 2＇-hydroxyacetophenone was studied.Good catalytic activities and high selectivities for flavanones were obtained in solvent-free reactions,which is attributed to the effect of benzyl and anthracenemetyl groups on the base sites of catalysts and the steric hindrance of futher reaction of flavanone with benzaldehyde.展开更多
Since the gas infrared absorption spectrum source intensity of several in a thousand, it is even less linewidth is only several nanometers occupying the than the noise of light source. The signal of gas absorption is ...Since the gas infrared absorption spectrum source intensity of several in a thousand, it is even less linewidth is only several nanometers occupying the than the noise of light source. The signal of gas absorption is submerged in the noise, so it is impossible to measure the concentration of gas with spectrum absorption directly. According to the principle and parameters of difference absorption system of CH4 gas, a detection circuit consisted of the lock-in amplifier is designed. The experiment results indicated that the detection circuit can satisfy the demand of the whole system, and the limit concentration is 150×10^-6.展开更多
基金Supported by the Research Startup Fund of Jilin University,China(Nos.4305050102H8,4305050102B5)the Basic Research and Operational Costs of Jilin University,China(Nos.421031196604,450060445293)
文摘Benzyl and anthracenemethyl groups were respectively bonded to the N atoms of 3-aminopropyl functionalized mesoporous SBA-15（APS-SBA-15） to obtain two new base catalysts over which the condensation reaction of benzaldehyde and 2＇-hydroxyacetophenone was studied.Good catalytic activities and high selectivities for flavanones were obtained in solvent-free reactions,which is attributed to the effect of benzyl and anthracenemetyl groups on the base sites of catalysts and the steric hindrance of futher reaction of flavanone with benzaldehyde.
基金Doctorate Foundation of Hebei Province(03547020D) Natural Science Foundation of Heilongjiang Province(F0312)
文摘Since the gas infrared absorption spectrum source intensity of several in a thousand, it is even less linewidth is only several nanometers occupying the than the noise of light source. The signal of gas absorption is submerged in the noise, so it is impossible to measure the concentration of gas with spectrum absorption directly. According to the principle and parameters of difference absorption system of CH4 gas, a detection circuit consisted of the lock-in amplifier is designed. The experiment results indicated that the detection circuit can satisfy the demand of the whole system, and the limit concentration is 150×10^-6.
