Glass-ceramics containing β-quartz as a main crystal phase based on the system of SiO2-Al2O3-Li2O-K2O-MgO-ZnO were investigated for the application to magnetic storage substrate for higher storage capacity. Parent gl...Glass-ceramics containing β-quartz as a main crystal phase based on the system of SiO2-Al2O3-Li2O-K2O-MgO-ZnO were investigated for the application to magnetic storage substrate for higher storage capacity. Parent glasses were prepared, then nucleated and crystallized at certain temperatures for 3-4 h. The crystallization kinetics of glass-ceramics was also studied. The grain size was estimated by Scherrer formula and image treatment of transmission electron microscopy （TEM）. The results showed that the Avrami exponent was determined to be 3.88, the activation energy 189.3＋7 k J/tool and the grain size 30-60 nm. A detailed microstructure of the glass-ceramics, including grain distribution and the morphology of nano-crystalline was characterized by TEM, X-ray diffraction （XRD）, differential scanning calorimeter （DSC）, differential thermal analysis （DTA）. The relationship between microstructure and mechanical properties was also discussed.展开更多
Using front face-pumped compact active mirror laser （CAMIL） structure, we have demonstrated an Yb：YAG/YAG composite ceramic disk laser with pumping wavelength at 970 nm. The laser has been operated in both continuo...Using front face-pumped compact active mirror laser （CAMIL） structure, we have demonstrated an Yb：YAG/YAG composite ceramic disk laser with pumping wavelength at 970 nm. The laser has been operated in both continuous-wave （CW） and Q-switching modes. Under CW operation, laser output power of 1.05 W with 2% transmission output coupler was achieved at the wavelength of 1031 nm. Q- switched laser output was gotten by using an acousto-optic Q-switch. The repetition rate ranged from 1 to 30 kHz and the pulse width varied from 166 to 700 ns.展开更多
掌握玻璃陶瓷MACOR的拉伸性能,对于其在航空航天、国防和其它工程中的应用,以及材料科学本身而言具有重要价值。巴西圆盘实验方法被用于研究加载速率对MACOR拉伸强度的影响。静态实验是在MTS试验机上完成的,动态实验是在6.35 mm SHPB实...掌握玻璃陶瓷MACOR的拉伸性能,对于其在航空航天、国防和其它工程中的应用,以及材料科学本身而言具有重要价值。巴西圆盘实验方法被用于研究加载速率对MACOR拉伸强度的影响。静态实验是在MTS试验机上完成的,动态实验是在6.35 mm SHPB实验装置中完成的。脉冲整形技术被用于实现试件两端力的动态平衡,以消除惯性效应的影响,从而实现准静态应力分析。实验结果表明,MACOR的拉伸强度与加载率相关,拉伸强度作为加载率的函数,当加载速率从0增加到5 780 GPa/s时,MACOR的拉伸强度从26 MPa增大到50 MPa。展开更多
基金The work was supported by the National Natural Science Foundation of China(Grant No.90206017)the High Tech.Program of Ministry of Science and Technology of China(Grant No.2003BA301A21)+2 种基金the Science and Technology Development Foundation of University of Shanghai(Grant No.02AK26)the Applied Materials(AM)Foundation(Grant No.0208)the Key Subject Construction Project(Material Science)of Shanghai Educational Committee.
文摘Glass-ceramics containing β-quartz as a main crystal phase based on the system of SiO2-Al2O3-Li2O-K2O-MgO-ZnO were investigated for the application to magnetic storage substrate for higher storage capacity. Parent glasses were prepared, then nucleated and crystallized at certain temperatures for 3-4 h. The crystallization kinetics of glass-ceramics was also studied. The grain size was estimated by Scherrer formula and image treatment of transmission electron microscopy （TEM）. The results showed that the Avrami exponent was determined to be 3.88, the activation energy 189.3＋7 k J/tool and the grain size 30-60 nm. A detailed microstructure of the glass-ceramics, including grain distribution and the morphology of nano-crystalline was characterized by TEM, X-ray diffraction （XRD）, differential scanning calorimeter （DSC）, differential thermal analysis （DTA）. The relationship between microstructure and mechanical properties was also discussed.
基金supported by the Shanghai Important Foundation Project under Grant No.07DJ14001.
文摘Using front face-pumped compact active mirror laser （CAMIL） structure, we have demonstrated an Yb：YAG/YAG composite ceramic disk laser with pumping wavelength at 970 nm. The laser has been operated in both continuous-wave （CW） and Q-switching modes. Under CW operation, laser output power of 1.05 W with 2% transmission output coupler was achieved at the wavelength of 1031 nm. Q- switched laser output was gotten by using an acousto-optic Q-switch. The repetition rate ranged from 1 to 30 kHz and the pulse width varied from 166 to 700 ns.
