The synthesis of polycrystalline aluminum oxynitride （AlON） powders was investigated by the carbothermal reduction and ni- tridation （CRN） of amorphous precursor obtained by wet chemical processing. Co-precipitati...The synthesis of polycrystalline aluminum oxynitride （AlON） powders was investigated by the carbothermal reduction and ni- tridation （CRN） of amorphous precursor obtained by wet chemical processing. Co-precipitation processing was employed to achieve amorphous precursor from AI（NO3）3 solution dispersed by nanosized carbon particles, which was composed of AI（OH）3 and C particles homogeneously. The effects of the content of carbon black, pH value, and calcination temperature on formation of A1ON phase were investigated by means of XRD, SEM and TEM, respectively. It was found that single phase AION powder could be synthesized when the resultant precursors were calcined at 1750℃ for 2 hours under flowing N2. Un- der optimal additional content of C （5.6wt%）, the resultant A1ON powders exhibited the primary particle size of about 1-3 μm with a specific surface area of 3.2 m2/g, which were superior to that of carbothermal reduction of immediate mixture of γ-A1203/C powders.展开更多
BACKGROUND： Scholars have supposed to establish animal models of optic neuropathy by pressing and partially amputating optic nerve, increasing intraocular pressure and injecting vasoconstrictor, etc., but the models ...BACKGROUND： Scholars have supposed to establish animal models of optic neuropathy by pressing and partially amputating optic nerve, increasing intraocular pressure and injecting vasoconstrictor, etc., but the models are greatly different from anterior ischemia optic neuropathy. Therefore, a more ideal method is needed to establish animal model of anterior ischemic optic neuropathy （AION）. OBJECTIVE ： To establish AION models in rats, observe the functional changes of fundus, fundus fluorescein angiography （FFA）, optical coherence tomography （OCT）, flash visual evoked potential （F-VEP）, and histopathologically confirm its reliability. DESIGN： A randomized control tria SETTINGS ： Department of Ophthalmology, Xi＇an Fourth Hospital; Xi＇an Institute of Ocular Fundus Diseases MATERIALS ： The experiments were carried out in the research room of Xi＇an Institute of Ocular Fundus Diseases from February 2005 to May 2006. Thirty healthy male SD rats of 4-5 weeks old, weighing 140-160 g, were provided by the animal experimental center of the Fourth Military Medical University of Chinese PLA [SCXK （Military）2002-005], and those without eye disease examined by slit lamp and direct ophthalmoscope after mydriasis were enrolled. The conditions for feeding mice without special pathogen were strictly followed. The rats were randomly divided into blank control group （n =5）, laser group （n =5）, hematoporphyrin derivative （HPD） group and AION group （n =15）, each group was numbered randomly. For each rat, the right eye was taken as the experimental eye, and the left one as the control one. METHODS： In the AION group, the rats were injected with HPD （10 mg/kg） via caudal vein, and then the optic discs were exposed to krypton red （647 nm, 80 mV） for 120 s, and the rats were in avoidance of light for 2 weeks postoperatively. Rats in the laser group were only exposed to krypton red （647 rim, 80 mV） for 120 s, and in avoidance of light for 2 weeks postoperatively; Those in the展开更多
文摘The synthesis of polycrystalline aluminum oxynitride （AlON） powders was investigated by the carbothermal reduction and ni- tridation （CRN） of amorphous precursor obtained by wet chemical processing. Co-precipitation processing was employed to achieve amorphous precursor from AI（NO3）3 solution dispersed by nanosized carbon particles, which was composed of AI（OH）3 and C particles homogeneously. The effects of the content of carbon black, pH value, and calcination temperature on formation of A1ON phase were investigated by means of XRD, SEM and TEM, respectively. It was found that single phase AION powder could be synthesized when the resultant precursors were calcined at 1750℃ for 2 hours under flowing N2. Un- der optimal additional content of C （5.6wt%）, the resultant A1ON powders exhibited the primary particle size of about 1-3 μm with a specific surface area of 3.2 m2/g, which were superior to that of carbothermal reduction of immediate mixture of γ-A1203/C powders.
基金a grant from Scientific Research Fund of Shaanxi Department of Hygiene, No. 04AC1
文摘BACKGROUND： Scholars have supposed to establish animal models of optic neuropathy by pressing and partially amputating optic nerve, increasing intraocular pressure and injecting vasoconstrictor, etc., but the models are greatly different from anterior ischemia optic neuropathy. Therefore, a more ideal method is needed to establish animal model of anterior ischemic optic neuropathy （AION）. OBJECTIVE ： To establish AION models in rats, observe the functional changes of fundus, fundus fluorescein angiography （FFA）, optical coherence tomography （OCT）, flash visual evoked potential （F-VEP）, and histopathologically confirm its reliability. DESIGN： A randomized control tria SETTINGS ： Department of Ophthalmology, Xi＇an Fourth Hospital; Xi＇an Institute of Ocular Fundus Diseases MATERIALS ： The experiments were carried out in the research room of Xi＇an Institute of Ocular Fundus Diseases from February 2005 to May 2006. Thirty healthy male SD rats of 4-5 weeks old, weighing 140-160 g, were provided by the animal experimental center of the Fourth Military Medical University of Chinese PLA [SCXK （Military）2002-005], and those without eye disease examined by slit lamp and direct ophthalmoscope after mydriasis were enrolled. The conditions for feeding mice without special pathogen were strictly followed. The rats were randomly divided into blank control group （n =5）, laser group （n =5）, hematoporphyrin derivative （HPD） group and AION group （n =15）, each group was numbered randomly. For each rat, the right eye was taken as the experimental eye, and the left one as the control one. METHODS： In the AION group, the rats were injected with HPD （10 mg/kg） via caudal vein, and then the optic discs were exposed to krypton red （647 nm, 80 mV） for 120 s, and the rats were in avoidance of light for 2 weeks postoperatively. Rats in the laser group were only exposed to krypton red （647 rim, 80 mV） for 120 s, and in avoidance of light for 2 weeks postoperatively; Those in the
