PbSe缓冲层表面微结构的演化及PbTe量子点的制备

用分子束外延技术在BaF2衬底（111）晶面上生长了PbSe单晶薄膜，研究了不同Se/PbSe束流比（Rf）对薄膜表面形貌的影响. 在无Se束流（Rf=0）下制备的PbSe薄膜表面呈现三维岛状结构. 当Rf较小（例如0.2) 时，样品表面呈现三角形孔状结构特征，孔的尺寸随Rf的增大而减小. 当Rf较大（0.6）时，样品表面的三角形孔消失，出现单原子层厚度的螺旋结构. 螺旋由台阶环构成，平面尺寸为1～3μm，表面台阶平均宽度为150nm，台阶间高度差为一个单原子层（1ML=0.354nm) . PbSe薄膜表面微结构的演化是由于Se束流改变了薄膜中的应变弛豫方式，从而改变了薄膜的生长模式引起的. 最后，我们在以螺旋结构为特征的PbSe缓冲层表面自组织生长了PbTe量子点，观察到两种高度分布的量子点.     

非正定磁介质增强无线功率传输效率研究

基于非正定磁介质对倏逝波的部分聚焦效应,研究非正定磁介质对磁谐振耦合式无线功率传输系统传输效率的影响。通过对平面圆螺旋结构的设计,在13. 56MHz 附近实现了法线方向磁导率为-1 的非正定磁介质。实验发现,将平面圆螺旋结构插入到具有相同谐振频率(13. 56MHz)的磁谐振耦合式无线功率传输系统中,可以显著地提高无线功率传输系统的传输效率。     

An involute spiral that matches Hermite data in the plane

A construction is given for a planar rational Pythagorean hodograph spiral, which interpolates any two-point G² Hermite data that a spiral can match. When the curvature at one of the points is zero, the construction gives the unique interpolant that is an involute of a rational Pythagorean hodograph curve of the form cubic over linear. Otherwise, the spiral comprises an involute of a Tschirnhausen cubic together with at most two circular arcs. The construction is by explicit formulas in the first case, and requires the solution of a quadratic equation in the second case.     

How to Construct a Logarithmic Rosette <Emphasis Type="Italic">(Without Even Knowing it)</Emphasis>

Paul Calter explains what a logarithmic rosette is and gives some examples of their occurrence in pavements. Then he gives a simple construction method which is totally geometric and requires no calculation. He then proves that it gives a logarithmic rosette, with the exception that the spirals are made up of straight-line segments rather than curved ones.     

连续螺旋叶片异面成形规律研究与有限元模拟

系统分析了连续螺旋叶片锥辊异面辗轧成形过程机理,确定了表征轧辊和轧件空间位置的主要参数。运用有限元软件对成形过程进行模拟,得出了影响螺旋叶片形态的5个主要参数对螺径D、螺距T影响规律并指明了实轧过程中轧制调整方法,从而为实际轧制生产提供借鉴。     

足尺寸GFRP筋HFRC柱的轴压性能与理论研究

为了研究玻璃纤维增强聚合物( glass fiber reinforced polymer, GFRP )筋混杂纤维混凝土( hybrid fiber reinforced concrete,HFRC)柱的轴压性能,进行了5个GFRP筋HFRC柱和1个未配筋HFRC柱的轴压试验,分析了GFRP箍筋间距和纵筋配筋率对GFRP筋HFRC柱轴压性能的影响规律。结果表明：提高GFRP纵筋配筋率可以提高试件的承载力,箍筋间距小的试件的延性明显高于箍筋间距大的试件。根据试验数据回归出了GFRP筋HFRC柱峰值应力、峰值应变以及承载力的计算公式。     

Fabricating 3D Metastructures by Simultaneous Modulation of Flexible Resist Stencils and Basal Molds

Metamaterials have gained much attention thanks to their extraordinary and intriguing optical properties beyond natural materials. However, universal high-resolution fabrications of 3D micro/nanometastructures with high-resolution remain a challenge. Here, a novel approach to fabricate sophisticated 3D micro/nanostructures with excellent robustness and precise controllability is demonstrated by simultaneously modulating of flexible resist stencils and basal molds. This method allows arbitrary manipulations of morphology, size, and orientation, as well as contact angles of the objects. Combined with a new alignment strategy of high-resolution, previously inaccessible architectures are fabricated with ultrahigh precision, leading to an excellent spectra response from the fabricated metastructures. This method provides a new possibility to realize true 3D metamaterial fabrications featuring high-resolution and direct-compatibility with broad planar lithography platforms.