当前中学化学教师对教学目标认识的调查

从学习者、实践者与研究者的视角,跟踪调查当前中学化学教师对教学目标的认识及其发展。调查表明:化学教师在新课程实践过程中不断深化对三维教学目标的认识,不断探索三维教学目标的实施。提出并分析了当前化学教学中存在着三维教学目标认识不清,意识淡薄,理解困惑,目标偏失等问题。     

高中化学必修与选修衔接教学的问题与建议

调查分析高中化学新课程实施以来必修与选修衔接教学的问题,提出了做好必修与选修衔接教学的建议.     

Classical simulation of atomic beam focusing and deposition for atom lithography

We start from the intensity distribution of a standing wave (SW) laser field and deduce the classical equation of atomic motion.The image distortion is analyzed using transfer function approach. Atomic flux density distribution as a function of propagation distance is calculated based on Monte-Carlo scheme and trajectory tracing method.Simulation results have shown that source imperfection,especially beam spread, plays an important role in broadening the feature width,and the focus depth of atom lens for real atomic source is longer than that for perfect source.The ideal focal plane can be easily determined by the variation of atomic density at the minimal potential of the laser field as a function of traveling distance.     

原子束计算全息技术的原理与实现

提出用计算全息技术来实现原子束全息成像，降低了原子束全息的实现难度.首先论述了原子束的波动性质以及如何形成相干性能良好的准单色原子波包，然后讨论了原子束计算全息片的设计步骤，并给出了制作完成的SiN薄膜计算全息片，最后详细介绍了原子束全息的实现方案.     

原子束计算全息片的设计与制作研究

在分析原子束计算全息片特点的基础上,提出采用罗曼Ⅲ型傅里叶变换计算全息图设计原子束计算全息片,给出设计步骤,然后提出采用电子束光刻编码矩孔图形,ICP各向异性刻蚀SiN薄膜的全息片制作方案,对全息片的制作工艺流程详细予以介绍,最后给出制作完成的SiN薄膜计算全息片.     

离散效应对高强度激光三次谐波转换的影响

使用分步傅里叶变换和四阶龙格库塔法(R-K) ，对高强度激光以Ⅰ/Ⅱ类角度失谐方式，在KDP晶体中的谐波转换进行了研究，详细讨论了离散效应对三次谐波转换的影响。结果表明，离散效应不但降低了三次谐波转换效率，而且使谐波光束质量显著降低；初始入射基频光束腰半径较小时，离散效应是二次谐波转换和三次谐波转换效率降低的主要因素，失谐角对三次谐波转换的影响较小；随着束腰半径的增加，离散效应的影响逐渐减小，失谐角对三次谐波转换的影响逐渐增加。     

一种可用于原子全息光刻的二元计算全息新方法

 原子全息光刻即采用二元计算全息片掩模来操纵原子，实现微细结构的制作。传统二元计算全息产生的全息片在重现时会产生不止一个实像，这对于原子全息光刻的操作是不利的。提出了一种非相位编码的方法，该方法利用基元函数叠加方式产生实的编码前全息图，再利用类似罗曼Ⅲ型的编码方式产生二元计算全息图。模拟结果表明，利用该方法产生的掩模板可以产生单一的同原始图案相对应的微细结构。     

Classical simulation of atomic beam focusing and deposition for atom lithography

We start from the intensity distribution of a standing wave (SW) laser field and deduce the classical equation of atomic motion. The image distortion is analyzed using transfer function approach. Atomic flux density distribution as a function of propagation distance is calculated based on Monte-Carlo scheme and trajectory tracing method. Simulation results have shown that source imperfection, especially beam spread, plays an important role in broadening the feature width, and the focus depth of atom lens for real atomic source is longer than that for perfect source. The ideal focal plane can be easily determined by the variation of atomic density at the minimal potential of the laser field as a function of traveling distance.     

用完全非共振光驻波聚焦原子制作纳米结构分析

用完全非共振激光驻波场对热原子束实现纳米量级的聚焦，可以降低原子光刻试验的难度. 用蒙特卡罗算法和轨迹模拟法分析原子源对原子聚焦的影响，结果表明靶的有效尺寸对纳米 图形线宽的影响远大于原子束的发散角和原子的纵向速度分布. 提出几种改进试验的方法. 关键词： 完全非共振激光驻波场 原子聚焦 纳米结构制作     

Fabrication of Nanoimprint Stamp Using Interference Lithography

Interference lithography is used to fabricate a nanoimprint stamp, which is a key step for nanoimprint lithography. A layer of chromium in thickness of about 20 nm is deposited on the newly cleaned fused silica substrate by thermal evaporation, and a layer of positive resist in thickness of 150nm is spun on the chromium layer. Some patterns, including lines, holes and pillars, are observed on the photoresist film by exposing the resist to interference patterns and they are then transferred to the chromium layer by wet etching. Fused silica stamps are fabricated by reactive ion etching with CHF3/O2 as etchants using the chromium layer as etch mask. An atomic force microscope is used to analyse the pattern transfer in each step. The results show that regular hole patterns of fused silica, with average full width 143nm at half maximum （FWHM）, average hole depth of 76nm and spacing of 450nm, have been fabricated. The exposure method is fast, inexpensive and applicable for fabrication of nanoimprint stamps with large areas.