Fast lateral photovoltaic effect in ferroelectric LiNbO_3 single crystals

We report the fast lateral photovoltaic effect in pure congruent LiNbO3 crystal induced by pulsed laser and continuous wave laser with wavelengths of 355, 532, and 1064 nm. A typical ultrafast photovoltage can be observed on the surface perpendicular to the c axis, With the rise time of 1.5 ns and the full-width at half-maximum of 1-2 ns, when the laser pulse inhomogeneously irradiates on the crystal. The peak open-circuit photovoltages show a linear dependence on the incident laser intensities. The mechanism of the photovoltaic characteristics is proposed.     

半球谐振陀螺（HRG）信号处理技术

半球谐振陀螺是一种高精度的振动陀螺,其信号处理技术是实现陀螺功能并取得预期性能的关键之一。本导出了半球振子振动位移信号的表达形式,提出了信号处理的基本方法并进行了详细的计算。其结果为自主设计半球谐振陀螺信号处理电路提供了依据。     

Ultraviolet laser-induced voltages in LaSrAlO4 single crystal

Laser-induced ultrafast photovoltaic effect is observed in LaSrAlO4 single crystal at ambient temperature without any applied bias. An open-circuit photovoltage is obtained when the wafer is irradiated by a 248-nm-KrF laser pulse of 20 ns duration. The response time and full width at half maximum of the photovoltage pulse are 6 ns and 19 ns, respectively, indicating that LaSrAlO4 single crystal has potential application in ultraviolet detector.     

怎样正确讲解乙烯与乙炔的活泼性

目前使用的中学化学课本上讲:“乙炔分子里的三键不稳定,其中两个键容易断开,所以乙炔具有非常活泼的化学性质”。而在讲乙烯时,则说:“乙烯分子里的双键不稳定,其中一个键容易断开,乙烯具有活泼的化学性质。”。     

陀螺寻北仪二位置寻北方案

讨论了挠性陀螺寻北仪二位置寻北方案。二位置寻北方案是利用陀螺仪敏感在相差180°的两个方向上的地球自转角速率分量,准确解算出地理真北方向与陀螺轴向的交角,从而实现寻北的方案。该方案利用转位对消了陀螺的常值漂移,因此,大大降低了对陀螺精度的要求,已经成功的应用于我所研制的CFN系列寻北仪中。实践证明:对于双轴陀螺采用二位置寻北方案易于实现,精度较高。     

有限周期电磁结构的区域分解快速算法

针对有限周期电磁结构,提出一种高效率的有限元分裂与互连算法.把原求解区域划分成若干个子区域,显著地降低了问题的复杂度.根据广义变分原理,采用拉格朗日乘子在子区域之间交换信息,并建立其相应的粗问题.研究子区域系数矩阵的可逆性.通过引入基本子区域,实现可扩展并行计算,且尤其适合于分析光子晶体等有限周期结构.