磁控溅射制备W掺杂VO2/FTO复合薄膜及其性能分析

为了获得相变温度低且热致变色性能优越的光学材料, 室温下在F:SnO₂ (FTO)导电玻璃基板表面沉积钨钒金属膜, 再经空气气氛下的热氧化处理, 制备了W掺杂VO₂/FTO复合薄膜, 利用X射线光电子能谱、X射线衍射和扫描电镜对薄膜的结构和表面形貌进行了分析. 结果表明: 高温热氧化处理过程中没有生成W, F, V混合氧化物, W以替换V原子的方式掺杂. 与采用相同工艺和条件制备的纯VO₂/FTO复合薄膜相比, W掺杂VO₂薄膜没有改变晶面取向, 仍具有(110)晶面择优取向, 相变温度下降到35 ℃左右, 热滞回线收窄到4 ℃, 高低温下的近红外光透过率变化量提高到28%. 薄膜的结晶程度明显提高, 表面变得平滑致密, 具有很好的一致性, 对光电薄膜器件的设计开发和工业化生产具有重要意义. 关键词： W掺杂 2')" href="#">VO₂ FTO导电玻璃 磁控溅射     

Nonreciprocal Head-on Collision Between Two Nonlinear Solitary Waves in Granular Metamaterials with an Interface

In this work,the head-on collision and transmission with nonreciprocal properties of opposite propagating solitary waves are studied,in which the interface betw...     

二氧化钒纳米点阵红外光学特性研究

针对二氧化钒纳米点阵从半导体到金属的可逆相变,考虑到点阵中各个点之间散射光的交互作用,基于VO2在不同温度和波长下的折射率和消光系数,以及小颗粒的吸收和散射特性,建立了VO2纳米颗粒的数学模型,研究了VO2纳米颗粒的相变光学特性.结果表明,随着波长变化,吸收截面相对散射截面占主导,金属相在980 nm附近出现吸收峰值|随着温度变化,可见光区域的消光系数变化较小,而红外区域较大,其中在近红外区域的消光系数变化最大.在纳米点阵中,消光截面随着颗粒间距变化,当颗粒间距增大时,消光峰值出现红移,且峰值大小也会随之增大|当间距超过一定数值后,峰值反而会逐渐减小.采用多孔氧化铝掩模的方法,通过磁控反应溅射制备VO2纳米点阵,测试结果表明其透过率比薄膜的透过率高.     

双光纤光栅外腔半导体激光器相干失效研究

根据双光纤Bragg光栅(FBG)外腔半导体激光器相干失效的物理过程, 运用速率方程和双FBG耦合模理论, 分析了双FBG外腔半导体激光器相干失效产生和控制的条件, 提出了实现和控制双FBG外腔半导体激光器相干失效多模稳定工作的方法. 双FBG外腔半导体激光器在相干失效下具有多模的稳定工作状态, 相干失效长度缩短, 相干失效长度内光谱稳定. 实验测量结果表明, 外腔反射率为3%时, 从非相干失效状态到相干失效状态, 半峰值全宽度从0.5 nm突然展宽到0.9 nm. 在相干失效状态下, 功率稳定, 边模抑制比大于45 dB, 在0℃–70℃工作温度范围内峰值波长漂移小于0.5 nm, 最小相干失效长度小于0.5 m. 双FBG外腔半导体激光器相干失效的应用对提高光纤放大器和光纤激光器的性能具有重要意义. 关键词： 非线性 半导体激光器 双光纤Bragg光栅 相干失效     

Wave localization in randomly disordered layered three-component phononic crystals with thermal effects

In this paper, the propagation and localization of elastic waves in randomly disordered layered three-component phononic crystals with thermal effects are studied. The transfer matrix is obtained by applying the continuity conditions between three consecutive sub-cells. Based on the transfer matrix method and Bloch theory, the expressions of the localization factor and dispersion relation are presented. The relation between the localization factors and dispersion curves is discussed. Numerical simulations are performed to investigate the influences of the incident angle on band structures of ordered phononic crystals. For the randomly disordered ones, disorders of structural thickness ratios and Lamé constants are considered. The incident angles, disorder degrees, thickness ratios, Lamé constants and temperature changes have prominent effects on wave localization phenomena in three-component systems. Furthermore, it can be observed that stopbands locate in very low-frequency regions. The localization factor is an effective way to investigate randomly disordered phononic crystals in which the band structure cannot be described.     

Scale effects on flexural wave propagation in nanoplate embedded in elastic matrix with initial stress

In this paper, the small-scale effects on the flexural wave in the nanoplate are studied. Based on the nonlocal continuum theory, the equation of wave motion is derived and the dispersion relation is presented. Numerical simulations are performed to investigate the influences of the scale coefficient, the surrounding elastic matrix and the initial stress on the wave propagation properties. The results show that the nonlocal model provides an appropriate method to investigate the characteristics of the flexural wave in the nanoplate. Furthermore, the direction and amplitude of the biaxial load, the stiffness of the shearing layer and the Winkler foundation can change the wave properties, significantly.     

Active feedback control of sound radiation in elastic wave metamaterials immersed in water with fluid–solid coupling

Acta Mechanica Sinica - Due to their potential properties unlike traditional materials and structures, elastic wave metamaterials have received significant interests in recent years. With the...     

考虑风剪切的漂浮式风力机气动特性研究

波浪与风载的共同作用下,海上风电机组平台存在多自由度运动,同时伴随着海上复杂的风况,其气动特性变化较为复杂。以NREL5MW风电机组为研究对象,在风剪切来流下,依据波浪和风载的作用规律,研究平台纵摇和纵荡运动对机组气动特性和绕流场细节的影响。结果表明:平台运动会造成风电机组气动性能的周期性波动,而风剪切作用使得风电机组平均发电量降低并加剧功率和推力的波动。风剪切会增大纵摇运动过程中展向截面的法向载荷幅值且波动加剧,但会降低与功率输出有关的切向受力;风剪切作用推迟了纵荡运动过程中展向截面法向和切向载荷峰值出现时刻,加剧载荷的波动。外叶展截面的法向和切向力系数曲线出现平台,加剧了叶片疲劳载荷,减小了功率输出。