We study the effects of a laser beam from the laser diode operating at 980nm on the violet-excited ZnS：Cu and SrAl2O4：Eu phosphor powders. Two contrary phenomena, i.e., infrared-induced permanent quenching and short...We study the effects of a laser beam from the laser diode operating at 980nm on the violet-excited ZnS：Cu and SrAl2O4：Eu phosphor powders. Two contrary phenomena, i.e., infrared-induced permanent quenching and short-lived enhancement of phosphorescence, are observed. The defect levels play a significant role in both the processes. It is demonstrated that the phosphorescence induced by the violet beam can be controlled by another infrared beam. The turn-off and turn-on behaviour means that doping luminescent centres into host materials is a considerable way to design a new all-optical switch and may control the output of laser beams in the fibre lasers and optical communications.展开更多
A new type of selenious polymer, silica-bound polybispropoxyethyl-selenidesilsesquinoxane, and its platinum complex were synthesized from bis-allyloxyethyl selenide via hydrosilylation with triethoxysilane, followed b...A new type of selenious polymer, silica-bound polybispropoxyethyl-selenidesilsesquinoxane, and its platinum complex were synthesized from bis-allyloxyethyl selenide via hydrosilylation with triethoxysilane, followed by immobilized on fumed silica, and then reacting with potassium chloroplatinite under nitrogen atmosphere in acetone. It was found that the platinum complex can catalyze the hydrosilylation of olefins with triethoxysilane effectively. The effects of the nature of the substrate, the amount of complex used, and the reaction temperature on the catalytic activity were investigated.展开更多
Changes of surface shape, aggregate state, and microstructure of Apocynum fiber before and after irradia-tion were studied by XRD, IR, SEM, ESR, and solid state 13C CP/ MAS NMR. The results show that the surface shape...Changes of surface shape, aggregate state, and microstructure of Apocynum fiber before and after irradia-tion were studied by XRD, IR, SEM, ESR, and solid state 13C CP/ MAS NMR. The results show that the surface shape and microstructure were not spoiled under 50 kGy gamma irradiation, while the crystallization of Apocynum fiber changed under 280 kGy . It also shows that different free radicals appear after irradiation and their concentration increases with the increase of irradiation dose.展开更多
Quenching and partitioning(Q&P)which provides a balance between toughness and strength is a promising heat treatment in iron and steel industry.However,there are three parameters(quenching temperature,partitioning...Quenching and partitioning(Q&P)which provides a balance between toughness and strength is a promising heat treatment in iron and steel industry.However,there are three parameters(quenching temperature,partitioning temperature and partitioning time)which affect the properties dramatically.As a result,it remains a challenge to get the best parameters in a low-cost way for Q&P process.Here,the orthogonal experimental design combined with a local optimization was adopted to optimize the quenching and partitioning parameters of 65Si2MnWA steel.By using this method,the combination between strength and ductility was optimized;meanwhile,the number of experiments was reduced significantly.When treated by quenching at 180℃followed by partitioning at 330℃for 20 min,the steel reached the best combination between strength and ductility.In detail,the product of ultimate tensile strength and reduction in area was 1.36 times(from 64.9 to 88.8 GPa%)that treated by quenching and tempering.In addition,owing to the grain refinement,the strength and ductility increase simultaneously.Specifically,the reduction in area increased by 27.4%(from 35.8%to 45.6%)coupled with a little improvement in ultimate tensile strength(7.4%).展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 60276035 and 60478041, and the Space Technology Foundation of China under Grant No 2002-HT-ZJDX-08.
文摘We study the effects of a laser beam from the laser diode operating at 980nm on the violet-excited ZnS：Cu and SrAl2O4：Eu phosphor powders. Two contrary phenomena, i.e., infrared-induced permanent quenching and short-lived enhancement of phosphorescence, are observed. The defect levels play a significant role in both the processes. It is demonstrated that the phosphorescence induced by the violet beam can be controlled by another infrared beam. The turn-off and turn-on behaviour means that doping luminescent centres into host materials is a considerable way to design a new all-optical switch and may control the output of laser beams in the fibre lasers and optical communications.
文摘A new type of selenious polymer, silica-bound polybispropoxyethyl-selenidesilsesquinoxane, and its platinum complex were synthesized from bis-allyloxyethyl selenide via hydrosilylation with triethoxysilane, followed by immobilized on fumed silica, and then reacting with potassium chloroplatinite under nitrogen atmosphere in acetone. It was found that the platinum complex can catalyze the hydrosilylation of olefins with triethoxysilane effectively. The effects of the nature of the substrate, the amount of complex used, and the reaction temperature on the catalytic activity were investigated.
基金Supported by National National Science Foundation (20464002)
文摘Changes of surface shape, aggregate state, and microstructure of Apocynum fiber before and after irradia-tion were studied by XRD, IR, SEM, ESR, and solid state 13C CP/ MAS NMR. The results show that the surface shape and microstructure were not spoiled under 50 kGy gamma irradiation, while the crystallization of Apocynum fiber changed under 280 kGy . It also shows that different free radicals appear after irradiation and their concentration increases with the increase of irradiation dose.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51401099).The authors would like to acknowledge Yi Zhou,Rui-yang Li,Zhi-xuan Chen and Lian-bo Luo for useful advice and discussion.
文摘Quenching and partitioning(Q&P)which provides a balance between toughness and strength is a promising heat treatment in iron and steel industry.However,there are three parameters(quenching temperature,partitioning temperature and partitioning time)which affect the properties dramatically.As a result,it remains a challenge to get the best parameters in a low-cost way for Q&P process.Here,the orthogonal experimental design combined with a local optimization was adopted to optimize the quenching and partitioning parameters of 65Si2MnWA steel.By using this method,the combination between strength and ductility was optimized;meanwhile,the number of experiments was reduced significantly.When treated by quenching at 180℃followed by partitioning at 330℃for 20 min,the steel reached the best combination between strength and ductility.In detail,the product of ultimate tensile strength and reduction in area was 1.36 times(from 64.9 to 88.8 GPa%)that treated by quenching and tempering.In addition,owing to the grain refinement,the strength and ductility increase simultaneously.Specifically,the reduction in area increased by 27.4%(from 35.8%to 45.6%)coupled with a little improvement in ultimate tensile strength(7.4%).
