利用熔融法制备了 Ba O- Sr O- Ti O2 - Si O2 (BSTS)系统玻璃 ,并经过一定晶化处理获得了极性微晶取向生长的玻璃陶瓷 ,用 X-射线衍射 (XRD)对取向生长进行了表征。利用晶格能和偶极子电场对极性玻璃陶瓷的微晶取向生长机理进行了分析 ...利用熔融法制备了 Ba O- Sr O- Ti O2 - Si O2 (BSTS)系统玻璃 ,并经过一定晶化处理获得了极性微晶取向生长的玻璃陶瓷 ,用 X-射线衍射 (XRD)对取向生长进行了表征。利用晶格能和偶极子电场对极性玻璃陶瓷的微晶取向生长机理进行了分析 ,表明极性玻璃陶瓷中微晶取向生长是由表面或界面控制 ,且由晶格能大小和偶极子电场决定。展开更多
SiO2 glassy materials with Ge crystals embedded were formed by heating GeO2/SiO2 glass at 700 in the presence of hydrogen. GeO2/SiO2 glass was prepared with the sol-gel technique. The Ge/SiO2 samples show a special ph...SiO2 glassy materials with Ge crystals embedded were formed by heating GeO2/SiO2 glass at 700 in the presence of hydrogen. GeO2/SiO2 glass was prepared with the sol-gel technique. The Ge/SiO2 samples show a special photoluminescence property and exhibit strong luminescence at 392 nm（3.12 eV）, secondary strong luminescence at 600 nm（2.05 eV） and weak luminescence at 770 nm（1.60 eV） when excited under 246 nm（5.01 eV） ultra-violet light at room temperature. The structure of this new luminescence material was studied with XRD, XPS, and TEM. The results show that the presence of nanometer sized（around 10 nm） Ge and GeO crystals in the SiO2 may cause the three-band photoluminescence. The GeO2/SiO2 glass without going through the reducing process only has GeO2 in the SiO2 glass, and does not show the photo-（luminescence）.展开更多
文摘利用熔融法制备了 Ba O- Sr O- Ti O2 - Si O2 (BSTS)系统玻璃 ,并经过一定晶化处理获得了极性微晶取向生长的玻璃陶瓷 ,用 X-射线衍射 (XRD)对取向生长进行了表征。利用晶格能和偶极子电场对极性玻璃陶瓷的微晶取向生长机理进行了分析 ,表明极性玻璃陶瓷中微晶取向生长是由表面或界面控制 ,且由晶格能大小和偶极子电场决定。
文摘SiO2 glassy materials with Ge crystals embedded were formed by heating GeO2/SiO2 glass at 700 in the presence of hydrogen. GeO2/SiO2 glass was prepared with the sol-gel technique. The Ge/SiO2 samples show a special photoluminescence property and exhibit strong luminescence at 392 nm（3.12 eV）, secondary strong luminescence at 600 nm（2.05 eV） and weak luminescence at 770 nm（1.60 eV） when excited under 246 nm（5.01 eV） ultra-violet light at room temperature. The structure of this new luminescence material was studied with XRD, XPS, and TEM. The results show that the presence of nanometer sized（around 10 nm） Ge and GeO crystals in the SiO2 may cause the three-band photoluminescence. The GeO2/SiO2 glass without going through the reducing process only has GeO2 in the SiO2 glass, and does not show the photo-（luminescence）.
文摘利用容忍因子和平均电负性力标差值作为钙钛矿稳定性的综合判据能很好说明钙钛矿稳定性。钙钛矿结构形成应满足容忍因子、电价和稳定性因子的条件限制 ,但这些条件是形成钙钛矿结构的必要条件 ,非充分条件。 Si O2 - Al2 O3玻璃相与钙钛矿 Ba Ti O3的固溶符合钙钛矿容忍因子和电价限制条件 ,且玻璃含量在 2 5 % (摩尔分数 )以下稳定性因子在 1.2以上 ,因而其形成的复合钙钛矿应能稳定存在 ,这与实际情况不符。另一方面 ,晶格能能很好地解释玻璃相与钙钛矿 Ba Ti O3的固溶使体系的稳定性降低。
