Analysis of Nanometer Structure for Chromium Atoms in Gauss Standing Laser Wave

The equation of motion of two-level chromium atoms in Gauss standing laser wave is discussed and the distribution of chromium atoms is given under different transverse velocity conditions. The results show that the focusing position of atoms will be affected by the transverse velocity of atoms. Based on the four-order Runge- Kutta method, the locus of chromium atoms in Gauss standing laser wave is simulated. The three-dimensional characteristics of nanometer structures are stimulated under perfect and emanative conditions.     

浅谈物理实验的教与学

探讨了物理实验教与学过程中思考的一些问题,介绍了华中科技大学物理实验教学中心的实践情况.     

一种提高光纤水听器解调系统噪声传递系数稳定性的多相相位生成载波解调算法

相位生成载波（PGC）调制解调是干涉型光纤水听器常用的解调方法。首先,分析并建立了PGC解调系统的噪声传递模型,研究了光源强度噪声对PGC解调输出噪声的影响机理,分析了调制深度和工作点两个参数对PGC解调噪声稳定性的影响。然后,提出了一种基于3×3耦合器的多相PGC解调方案,即在传统PGC解调架构中引入3×3耦合器进行多相检测,利用3×3耦合器的相移特性对三路干涉信号进行融合处理。在不同的调制深度条件下,该方案可以降低水听器工作点变化所引起的光源强度噪声传递系数波动范围。实验结果显示,在常用的调制深度范围（1.7～3.4）内,工作点变化导致的噪声传递系数波动峰谷值小于0.5 dB,噪声稳定性相比传统PGC解调系统显著提升。     

基于Tracker的方位径向摆影响因素实验研究

为探究方位径向摆运动的影响因素,使用影像追踪软件Tracker分析径向摆运动轨迹,控制多个变量,得到不同条件下摆球运动图像,计算得到转化时间.通过分析图像,发现方位径向摆的运动受到方位角的大小、弹性杆直径、弹性杆长度、径向摆摆长等多因素影响.     

Spin Pumping from a Quantum Dot in the Presence of Decoherence

We study the pumped spin current of an interacting quantum dot tunnel coupled to a single lead in the presence of electron spin resonance （ESR） field. The spin decoherence in the dot is included by the Bffttiker approach. Using the nonequilibrium Green＇s function technique, we show that ESR-induced spin flip can generate finite spin current with no charge transport. Both the Coulomb interaction and spin decoherence decrease the amplitude of spin current. The dependence of pumped spin current on the intensity and frequency of ESR field, and the spin decoherence is discussed.     

Characterization Method of Polycrystalline Materials Using Conductive Atomic Force Microscopy

An apparatus for characterization of polycrystalline materials based on conductive atomic torce microscopy （cAFM） is developed and a quantitative measurement of electrical characteristics of individual grains in polycrystalline ZnO ceramic is demonstrated. Improvement of the experimental method is presented. Experimental results illuminate unambiguously the different electrical characteristics between individual grains, suggesting the suitability and maneuverability of this method in the study of local structure or properties and their relationship in polycrystalline materials such as semi-conducting ceramics.     

Temperature Dependence of Photoluminescence from Single and Ensemble InAs/GaAs Quantum Dots

We investigate the temperature dependence of photoluminescence from single and ensemble InAs/GaAs quantum dots systematically. As temperature increases, the exciton emission peak for single quantum dot shows broadening and redshift. For ensemble quantum dots, however, the exciton emission peak shows narrowing and fast redshift. We use a simple steady-state rate equation model to simulate the experimental data of photoluminescence spectra. It is confirmed that carrier-phonon scattering gives the broadening of the exciton emission peak in single quantum dots while the effects of carrier thermal escape and retrapping play an important role in the narrowing and fast redshift of the exciton emission peak in ensemble quantum dots.     

实景课堂在化学教学中的应用

正实景课堂是指通过信号采集设备,将工厂和企业的真实场景传送到学校教学课堂,也把课堂实时情况反馈给工厂和企业的实景老师和专家,从而实现学生、授课教师、实景老师以及现场专家多方互动交流的"多讲师"教学新方法[1-2]。1化学实景课堂教学流程以"乙醇"实景课堂为例:课前,实景老师联系工厂和企业的工程师或专家,准备好介绍内容;授课教师提前准备好授课教案以及学生学案;课程开始之前1小时,技术人员提前进行连线调试,确     

基于层次分析的主成分分析法及其应用

在分析了传统的层次分析法和主成分分析法的优缺点的基础上,扬长避短的将两种方法结合在一起,讨论了基于层次分析的主成分分析法.与新兴的决策评估方法相比,例如直觉模糊层次分析法,基于层次分析的主成分分析法更具有简洁性和直观性.最后,将方法应用于登陆作战的目标选择,得到了与实战结果相同的结论,验证了方法的可行性.     

带有波前编码板的虹膜采集光学系统的设计

设计了一款采用波前编码技术的虹膜采集光学系统,以实现大景深、自然非约束状态下的成像.以传统的光学系统评价指标斯特利尔比和能量集中度作为波前编码系统的成像特征,利用ZEMAX软件对波前编码系统进行设计,权衡了离焦不敏感性和图像可恢复性.比较了带有立方相位编码板和带有修正项的立方相位编码板的虹膜采集系统以及传统系统的焦深延拓效果.发现采用立方相位编码板的虹膜采集光学系统的焦深延拓效果最佳,其焦深是传统系统的8倍.该系统增大了虹膜采集的距离,对于自然状态虹膜成像系统设计有一定的参考价值.