A 4 mm gap semi-insulating （SI） GaAs photoconductive switch （PCSS） was triggered by a pulse laser with a wavelength of 1064 nm and a pulse energy of 0.5 mJ. In the experiment, when the bias field was 4 kV, the swi...A 4 mm gap semi-insulating （SI） GaAs photoconductive switch （PCSS） was triggered by a pulse laser with a wavelength of 1064 nm and a pulse energy of 0.5 mJ. In the experiment, when the bias field was 4 kV, the switch did not induce self-maintained discharge but worked in nonlinear （lock-on） mode. The phenomenon is analyzed as follows： an exciton effect contributes to photoconduction in the generation and dissociation of ex- citons. Collision ionization, avalanche multiplication and the exciton effect can supply carrier concentration and energy when an outside light source was removed. Under the combined influence of these factors, the S1-GaAs PCSS develops into self-maintained discharge rather than just in the light-controlled prebreakdown status. The characteristics of the filament affect the degree of damage to the switch.展开更多
Titanium phosphates were prepared from titanium chloride and sodium pyrophosphate at various pH in hydrothermal process as a novel white pigment for cosmetics.Their chemical composition,powder properties,photo catalyt...Titanium phosphates were prepared from titanium chloride and sodium pyrophosphate at various pH in hydrothermal process as a novel white pigment for cosmetics.Their chemical composition,powder properties,photo catalytic activity,colour phase and smoothness were studied.The obtained materials had a higher Ti/P ratio than that used in preparation conditions because of the formation of titanium oxide and hydroxide.The samples prepared at pH=4 had particles smaller than 100μm.Titanium phosphates had less photo catalytic activity to protect the sebum on the skin.The obtained materials in hydrothermal process and their thermal products at 100℃showed high reflectance in the range of visible light.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.50837005,10876026)the State Key Laboratory of Electrical Insulation for Power Equipment(No.EIPE09203).
文摘A 4 mm gap semi-insulating （SI） GaAs photoconductive switch （PCSS） was triggered by a pulse laser with a wavelength of 1064 nm and a pulse energy of 0.5 mJ. In the experiment, when the bias field was 4 kV, the switch did not induce self-maintained discharge but worked in nonlinear （lock-on） mode. The phenomenon is analyzed as follows： an exciton effect contributes to photoconduction in the generation and dissociation of ex- citons. Collision ionization, avalanche multiplication and the exciton effect can supply carrier concentration and energy when an outside light source was removed. Under the combined influence of these factors, the S1-GaAs PCSS develops into self-maintained discharge rather than just in the light-controlled prebreakdown status. The characteristics of the filament affect the degree of damage to the switch.
文摘Titanium phosphates were prepared from titanium chloride and sodium pyrophosphate at various pH in hydrothermal process as a novel white pigment for cosmetics.Their chemical composition,powder properties,photo catalytic activity,colour phase and smoothness were studied.The obtained materials had a higher Ti/P ratio than that used in preparation conditions because of the formation of titanium oxide and hydroxide.The samples prepared at pH=4 had particles smaller than 100μm.Titanium phosphates had less photo catalytic activity to protect the sebum on the skin.The obtained materials in hydrothermal process and their thermal products at 100℃showed high reflectance in the range of visible light.
