超疏水表面黏附性的研究进展

结合作者课题组的相关工作,简要地论述了超疏水表面固液黏附性的主要影响因素和评价标准,介绍了天然和人工仿生具有特殊黏附性超疏水表面的研究进展,包括超疏水高黏附表面、超疏水低黏附表面、可控黏附性超疏水表面、各向异性黏滞力超疏水表面、黏滞力响应性智能超疏水表面以及超亲/超疏水图案表面制备及运用.特别介绍了作者研究小组在仿生可控黏滞力超疏表面制备以及超亲/超疏水图案表面运用的研究.最后对具有特殊黏附性超疏表面的研究进行总结和展望.     

三维大型任意阵列宽带波束指向性图的快速计算

为解决常规频域直接方法计算大型三维阵列宽带波束图(BP)速度较慢,无法满足大型三维宽带阵优化设计需求的问题,提出了一种适用于大型三维任意阵列的宽带BP图的快速算法.在利用二维非均匀快速傅里叶变换(NUFFT)伴随操作实现二维阵列BP频域快速计算方法的基础上,引入第三空间频率变量,将与阵元纵向坐标有关的相位因子转化为第三...     

钛材表面疏水图案化对成骨细胞生长的影响

本文通过共沉淀法合成纳米羟基磷灰石,然后采用电泳沉积法在钛材表面沉积羟基磷灰石涂层,并通过氟硅烷浸泡法构建疏水化图案,对制得的样品采用透射电镜、扫描电镜、X射线衍射、红外光谱仪、接触角测量仪进行表征,并与成骨细胞共培养,采用MTT、ALP法检测疏水图案对成骨细胞生长的影响。结果表明,本实验成功在钛材表面构建了疏水图案,且这种图案对成骨细胞生长有一定的抑制作用,通过构建不同的疏水图案,可以达到调控成骨细胞生长方向的作用。     

优化扬声器阵列的指向性与声功率级

提出了同时优化扬声器阵列的指向性和声功率级的方法。运用该方法可以优化扬声器阵列的输入电压分布,获得指向性和声功率级二者兼顾的扬声器阵列。本方法不必使用复杂的与频率相关的信号处理装置。模拟结果和实验测量结果表明该方法是可行的和有效的。     

脆性金属玻璃断面上的奇妙图案

文章简要介绍了脆性块体金属玻璃(简称BMG)断裂面上几种主要的图案花样:河流花样、"韧窝"结构花样和自组装条纹结构花样,并总结了目前对上述各种形貌形成机理的可能的物理解释.对BMG断裂面上形貌的研究可以揭示材料的断裂机理,有助于更深刻地理解材料的力学性能,开发高性能金属玻璃材料,并为工程选材提供安全标准.     

弯曲圆盘驱动的双Helmholtz共振腔换能器

使用双面同相振动的弯曲圆盘换能器驱动双Helmholtz共振腔,既放大了弯曲圆盘换能器弯曲共振频率以下频段的声输出,又利用两个Helmholtz共振腔的同相声源辐射模型实现了在Helmholtz共振频率处的"∞"字形垂直指向性,实现了低频指向性声发射。阐述了换能器实现"∞"字形低频指向性发射的机理,研究了腔体长度、金属圆片厚度及弯曲圆盘边缘简支厚度等关键结构参数对Helmholtz共振频率的影响,求解了换能器的发送电压响应、指向性等参数。依据仿真结果制作了实验样机,在消声水池中进行了电声性能测试。测试结果显示,指向性形状及液腔共振频率与仿真结果基本相符。这种由弯曲圆盘驱动的双Helmholtz共振腔水声换能器为实现水声换能器小尺寸、低频指向性发射提供了一种技术手段。      

微图案化钙磷盐膜层的电化学构筑及其生物性能

基于表面分子自组装和光催化转印技术,在TiO2膜层表面获得超亲/超疏水阵列微图案模板,结合电化学沉积技术,成功制备了微图案化钙磷盐膜(CaP)层.扫描电子显微镜(SEM)和电子探针分析(EPMA)结果表明,通过超亲/超疏水阵列微图案模板可构筑高空间分辨的微图案化钙磷盐膜层.微图案化钙磷盐膜层的体外MG-63细胞培养证实,细胞对钙磷盐膜层微单元有强烈的选择性粘附作用,从而可望控制细胞在微单元中的贴壁生长,实现高通量评价细胞行为.     

Patterned growth of ZnO nanofibers

A simple method is adopted to grow ZnO nanofibers laterally among the patterned seeds designed in advance on silicon substrate. The preparation of seed lattices is carried out by lithographing the metal zinc film evaporated on the substrate. A layer of aluminum is covered on the zinc layer to prevent the ZnO nanorods vertically growing on the top surface. After oxidation, the patterned ZnO/Al2O3 spots are formed at the sites for the horizontal growth of ZnO nanofibers by the vapor phase transportation （VPT） method using the zinc powders as source material.     

Theoretical analysis and experimental results of interference striation pattern of underwater target radiated noise in shallow water waveguide

Waveguide invariant in shallow water is an attractive topic in recent three decades. The interference phenomena of direct wave of radiated noise of underwater target and reflection wave from sea surface and sea bottom can be considered as a typical case of shallow water waveguide.The interference striation pattern of direct wave and its reflection is the effective and comprehensive figure for better understanding the essence of shallow water waveguide invariant.The theoretical analysis of interference phenomena generated by direct wave of radiated noise of underwater target and its reflection wave from sea surface and sea bottom is presented in this paper.It is shown that the interference wave resulted by sea surface reflection will produce striation pattern centered at high frequency band.But the interference of nulling frequency resulted by sea bottom reflection may be at low frequency or high frequency, it strongly depends on the acoustic behavior of sea bottom.The relationship between main parameters of interference striation pattern and target,receiver,and environment is derived.It is shown that the interference striation have the shape of hyperbolic curve.The equation set of the hyperbolic curve and its asymptotic line is presented.The at sea experiment carried out in South China sea shows some interesting results.A part of data processing results are illustrated in this paper.The results expressed in this paper show that the interference striation pattern can be used,in some conditions,as a potential means for target recognition.     

Fluorescence lifetime measurement from a designated single-bunch in the BEPCⅡ colliding mode

Fluorescence lifetime measurement in the time domain requires excitation from a well separated single bunch using synchrotron light sources. In the colliding mode of the Beijing Electron Positron Collider Ⅱ (BEPCⅡ), a hybrid filling pattern was realized such that a single bunch was placed in the middle of a large gap between two multi-bunch groups. Detection of fluorescence lifetime, based on the excitation of the light pulse from this designated single-bunch, was established at Beamline 4B8 of the Beijing Synchrotron Radiation Facility (BSRF). The timing signal of the BEPCII was utilized as a trigger to gate this fluorescence event. L-Tryptophan amino acid, a known lifetime standard, was selected to assess the lifetime measurement performance. The measured lifetime was consistent in both colliding and single-bunch mode with the time resolution down to 450 ps. Moreover, both the bunch purity and the fine structure of the hybrid filling pattern were characterized.