灯具曲面设计中的光线追踪法

采用灯具曲面上一定区域内入射光通量分布比例与反射光通量分布比例对等的原则，确定出每一条入射光线所对应的反射光线方向，进而求出为实现该目的所需的切点（切线），并用例子说明了其设计过程     

Alzheimer's disease: fundamental and therapeutic aspects

Alzheimer's disease is the most common type of progressive and debilitating dementia affecting aged people. In some early — as well as late-onset familial cases, a genetic linkage with chromosomes 14, 21 (early-onset) or 19 (late-onset) has been indicated. Furthermore, a direct or indirect role has been attributed to normal or structurally altered amyloid -protein (concentrated in senile plaques) and/or excessively phosphorylated tau protein (located in neurofibrillary tangles). Degeneration of cholinergic neurons and concomitant impairment of cortical and hippocampal neurotransmission lead to cognitive and memory deficits. Several compounds are being tested in attempts to prevent and/or cure Alzheimer's disease, including tacrine, which has very modest efficacy in a sub-group of patients, and new acetylcholinesterase inhibitors. Pilot experiments have also been launched using nerve growth factor (NGF) to prevent or stabilize the processes of cholinergic pathway degeneration. Alternatively, antioxidants, free radical scavengers and/or non steroidal anti-inflammatory agents may be screened as potential therapies for neurodegenerative diseases induced by multiple endogenous and/or exogenous factors. The recent use of transgenic mice, in parallel with other genetic, biochemical and neurobiological systems, in vivo and/or in vitro (cell cultures), should accelerate the discovery and development of specific drugs for the treatment of Alzheimer's disease.     

Synaptogenesis in hippocampal cultures

Hippocampal cultures offer unique advantages for the study of neuronal development and synaptogenesis. Studies performed on this model enabled dissection of the temporal sequence of events which lead to the differentiation of pre- and postsynaptic compartments. Received 27 January 1999; received after revision 4 March 1999; accepted 5 March 1999     

基于NOLM中XPM效应的光脉冲压缩研究

提出了利用色散位移光纤(DSF)构成的非线性光纤环路镜(NOLM)中交叉相位调制(XPM)效应获得光脉冲压缩的新方法,并进行了相关分析.数值结果表明:在NOLM中,利用泵浦脉冲与其中一路信号脉冲共同传输时的交叉相位调制(XPM)效应,可使最终输出的信号脉冲获得较好的压缩.     

基于双曲面镜的全向摄像机视觉实现方法

给出了一种由双曲面镜和常规摄像机构成全向摄像机视觉系统的实现方法,通过对双曲面镜几何模型、全向成像原理和摄像机结构的分析,得出满足单一视点约束的全向摄像机的设计方法;并给出了基于图像的系统安装方法;最后通过将实际图像平面坐标系中的点投影到虚拟图像平面的方法对全向图像进行重投影,校正得到任意方向无畸变的透视投影图像.实验结果表明,该系统不仅满足人眼观察的需要,也可用于视频监视 ,目标跟踪和立体视觉.     

低功耗高电源抑制比CMOS带隙基准源设计

基于Ahujia基准电压发生器设计了低功耗、高电源抑制比CMOS基准电压发生器电路.其设计特点是采用了共源共栅电流镜,运放的输出作为驱动的同时还作为自身的偏置电路;其次是采用了带隙温度补偿技术.使用CSMC标准0.6μm双层多晶硅n-well CMOS工艺混频信号模型,利用Cadence的Spectre工具对其仿真,结果显示,当温度和电源电压变化范围为-50-150℃和4.5-5.5 V时,输出基准电压变化小于1.6 mV(6.2×10-6/℃)和0.13 mV;低频电源抑制比达到75 dB.电路在5 V电源电压下工作电流小于10 μA.该电路适用于对功耗要求低、稳定度要求高的集成温度传感器电路中.     

最小左右对称模型中单个Z'玻色子的产生(英文)

左右对称模型中的一般特征是左右手的费米子项通过一个新的中性规范玻色子Z'来联结.研究了在左右镜像模型和左右对称模型中新的规范玻色子Z'通过e-γ凝聚的产生过程,并讨论了在TeV能级的直线对撞机上探测该新粒子的可能性.结果表明,该过程的产生截面范围为16.23fb～206.2fb,并且左右镜像模型中的产生截面大于左右对称模型中的产生截面.在未来的高能直线对撞机上该新粒子的信号可以通过其轻子衰变道Z'→l l-来探测.     

物理化学与应用化学信息资源镜像系统的建立及技术探讨

以Teleport Pro离线浏览器作为镜像工具，下载Internet上丰富的化学信息资源，建立了物理化学与应用化学信息资源镜像系统，并对镜像过程出现的有关解决方法进行了深入的探讨。     

从镜子意象看中国小说的发展演变

镜子的历史也是人类自身发展的历史。镜子意象被写入我国古代小说中,伴随着小说的发展演变直至今天,镜子的功能,在小说发展演变的同时也在演进变化。小说中的镜子实际上是一面反映人类自身不断发展进步的镜子。通过小说中的镜子意象,人类得以反观自身,反观社会,这其实才是镜子的真正意义所在。     

自锁模Cr∶LiSAF飞秒激光器的谐振腔设计

以自聚焦理论为基础,考虑象散补偿的情况,推导出包括LiSAF晶体在内的三镜腔的非线性传输矩阵.由此,可计算出腔内及晶体内部光束半径随激光功率的变化,并确定腔的较佳参数.在实验上实现了三镜腔Cr∶LiSAF激光器的自锁模运转.