The contents of total phenolics, flavonoid and chlorogenic acid in two types of sand pear fruits 〔\%Pyrus pyrifolia \%(Burm. f.) Nakai〕, and antioxidant activities in its juice were analysed. The results showed that...The contents of total phenolics, flavonoid and chlorogenic acid in two types of sand pear fruits 〔\%Pyrus pyrifolia \%(Burm. f.) Nakai〕, and antioxidant activities in its juice were analysed. The results showed that the contents of total phenolics and flavonoid in fruit of black sand pear were higher than that of red sand pear fruit obviously, but chlorogenic acid contents were not different in two types of sand pear fruit. The CI\-\{50\}of scavenging ·OH of their juice were 30.6 μL and 69.5 μL respectively. And their juice could inhibit lipid peroxidation significantly in brain and liver homogenates of rat. These implied that sand pear fruits have large quantity of antioxidant matters and were worthy to be further researched.展开更多
In order to reduce the curing temperature, shorten the curing time of phenol-formaldehyde(PF) resin adhesive, and ensure the good water-solubility, NaOH and Ba(OH)_2 were used as compound catalysts. The influences of ...In order to reduce the curing temperature, shorten the curing time of phenol-formaldehyde(PF) resin adhesive, and ensure the good water-solubility, NaOH and Ba(OH)_2 were used as compound catalysts. The influences of the adding time of Ba(OH)_2, the adding amount of NaOH, Ba(OH)_2 and resorcinol on the properties of adhesives were studied. The properties of NaOH catalyzed phenol-formaldehyde(PF) adhesive, NaOH and Ba(OH)_2 compound catalyzed PF adhesive, NaOH and Ba(OH)_2 compound catalyzed phenol-resorcinol-formaldehyde(PRF) adhesive, and the prepared recombinant bamboo with three kinds of adhesives were compared. The experimental results show that NaOH and Ba(OH)_2 compound catalyst not only shortens the curing time of PF adhesive, but also guarantees the suitable water solubility of adhesive. After copolycondensation with resorcinol, the curing time of adhesive is further shortened, the water solubility is improved obviously, and the highest bonding strength is obtained. Infrared spectrum analysis shows that the reaction activity point of NaOH and Ba(OH)_2 compound catalyzed PRF adhesive will increase, so that both the curing temperature and curing enthalpy decrease.展开更多
文摘The contents of total phenolics, flavonoid and chlorogenic acid in two types of sand pear fruits 〔\%Pyrus pyrifolia \%(Burm. f.) Nakai〕, and antioxidant activities in its juice were analysed. The results showed that the contents of total phenolics and flavonoid in fruit of black sand pear were higher than that of red sand pear fruit obviously, but chlorogenic acid contents were not different in two types of sand pear fruit. The CI\-\{50\}of scavenging ·OH of their juice were 30.6 μL and 69.5 μL respectively. And their juice could inhibit lipid peroxidation significantly in brain and liver homogenates of rat. These implied that sand pear fruits have large quantity of antioxidant matters and were worthy to be further researched.
基金Funded by the China Postdoctoral Science Foundation Funded Project(2015M572276)the Natural Science Foundation of Hunan Province,China(2016JJ3184)the Hunan Major Science and Technology Projects(2011FJ1006)
文摘In order to reduce the curing temperature, shorten the curing time of phenol-formaldehyde(PF) resin adhesive, and ensure the good water-solubility, NaOH and Ba(OH)_2 were used as compound catalysts. The influences of the adding time of Ba(OH)_2, the adding amount of NaOH, Ba(OH)_2 and resorcinol on the properties of adhesives were studied. The properties of NaOH catalyzed phenol-formaldehyde(PF) adhesive, NaOH and Ba(OH)_2 compound catalyzed PF adhesive, NaOH and Ba(OH)_2 compound catalyzed phenol-resorcinol-formaldehyde(PRF) adhesive, and the prepared recombinant bamboo with three kinds of adhesives were compared. The experimental results show that NaOH and Ba(OH)_2 compound catalyst not only shortens the curing time of PF adhesive, but also guarantees the suitable water solubility of adhesive. After copolycondensation with resorcinol, the curing time of adhesive is further shortened, the water solubility is improved obviously, and the highest bonding strength is obtained. Infrared spectrum analysis shows that the reaction activity point of NaOH and Ba(OH)_2 compound catalyzed PRF adhesive will increase, so that both the curing temperature and curing enthalpy decrease.
