锯齿型石墨烯带缺陷改性方法研究

采用基于密度泛函理论的非平衡格林函数, 对具有不同缺陷构型的锯齿型石墨烯带(zigzag graphene nanoribbon, ZGNR) 的输运性质进行了理论计算与模拟. 研究表明, 相同数目、 不同构型缺陷结构对ZGNR的导电特性将产生不同的影响. 如A-B构型双空缺对ZGNR电导的影响最为显著, 而A-A构型双空缺对其电导的影响最小. 更为重要的是, 当引入碳环构型缺陷时, ZGNR将被改性, 即由原本的金属性质转变为半导体性质, 为缺陷调控石墨烯导电特性提供了理论依据.     

用回归分析研究高考课程设置与计分比例问题

本文是在应用物理系陈纲付教授支持与指导下完成的.应用数学系付主任陈祖荫付教授审阅了全文。在此表示感谢.前言 高等学院入学考试是我国规模最大的国家考试,受教育部委托,《人民教育》杂志曾在全国开展了关于高考课程设置与计分比例的讨论,说明这个问题具有重大意义.但讨论中     

基于AFM的药物刺激前后淋巴瘤活细胞的形貌及弹性的变化

原子力显微镜(AFM)的发明为研究单个活细胞的形貌结构及物理特性提供了新的技术手段.然而,由于缺少合适的固定方法,利用AFM对动物悬浮活细胞的形貌进行高分辨率成像还面临着巨大的挑战.本文提出一种基于微柱阵列和静电吸附相结合的动物悬浮细胞固定方法.通过微柱阵列的机械钳制和多聚赖氨酸的静电吸附实现了对单个淋巴瘤B细胞的固定,并在此基础上利用AFM动态观测了不同浓度Rituximab刺激下淋巴瘤B细胞的表面形貌及弹性的变化.经过0.2 mg·mL-1的Rituximab刺激2 h后,细胞表面的褶皱增加,细胞的杨氏模量从196 kPa减小到183 kPa.经过0.5 mg·mL-1的Rituximab刺激2 h后,细胞形貌发生显著变化并出现突起结构,细胞的杨氏模量从234 kPa减小到175 kPa.实验结果表明淋巴瘤细胞形貌和弹性变化的幅度随着Rituximab刺激浓度的增加而增加,加深了对Rituximab作用效果的认识.     

Planning and control of 3-D nano-manipulation

The use of atomic force microscope (AFM) as a nanomanipulator has been evolving for various kinds of nano-manipulation tasks. Due to the bow effect of the piezo scanner of the AFM, the AFM space is different from the Cartesian space. Traditional nanomanipulation based on AFM is only a 2-D operation and does not consider the bow effect of the piezotube. In this paper, different 3-D nanomanipulation tasks using AFM such as nanolithography, pushing and cutting have been discussed. 3-D path planning is performed directly in the AFM space and the 3-D paths are generated based on the 3-D topography information of the surface represented in the AFM space. This approach can avoid the mappings between the AFM space and Cartesian space in planning. By following the generated motion paths, the tip can either follow the topography of the surface or move across the surface by avoiding collision with bumps. Nanomanipulation using this method can be considered as the “true“ 3-D operations since the cantilever tip can be controlled to follow any desired 3-D trajectory within the range of AFM space. The experimental study shows the effectiveness of the planning and control scheme.