提高聚氨酯表面硅橡胶涂层粘接性研究

利用表面处理并借助硅烷偶联剂大幅提高了聚氨酯/硅橡胶(PU/SR)的界面粘接性.利用红外光谱、水接触角以及表面元素分析对PU表面处理效果及偶联剂的反应效果进行检测,利用扫描电镜对材料的表面形貌及界面情况进行观察.并对不同方法得到的PU/SR界面进行剪切和振动疲劳测试以考察其粘接效果并进行比较.结果表明,经过硫酸短时处理过的PU表面生成大量羟基,使得亲水性提高,并大大增强了端异氰酸酯基硅烷偶联剂与PU的接枝反应效果.当室温缩合固化的硅橡胶预聚体涂覆到其表面后,以化学键联接在PU表面的硅烷偶联剂又可以与硅橡胶一起缩合,从而有效的提高了PU/SR的界面粘接性.     

Red top-emitting organic light-emitting device with improved efficiency and saturated color

In this work, characteristics of microcavity top-emitting red organic light-emitting device (TEROLED) having metallic electrodes had been examined. The TEOLED shows the higher efficiency in comparison with that of the bottom OLED. However, color variation with the increasing view angles is also observed. For the purpose of diminishing the blue-shift of resonant wavelength (RW) in the device with increasing view angle, the effect of out-coupling layer on the emission properties of the TEOLED is discussed in detail. Finally, the out-coupling layer was introduced in theory without sacrificing the efficiency through precise optical simulation.     

Study on inverse taper based mode transformer for low loss coupling between silicon wire waveguide and lensed fiber

We have simulated the coupling loss of three types of Inverse Taper and taper-lensed fiber using three dimensional (3D) semi-vectorial beam propagation methods (BPM) respectively. Our results showed that the performances of exponential inverse taper and quadratic inverse taper were better than the commonly used linear inverse taper. Especially, for TM mode the improvement in the reduction of devices size is 53% and 136% for exponential and quadratic inverse taper compared with the linear inverse taper.     

针板型触发电晕稳定开关的特性

 为了验证在空气状态下电晕稳定开关的重复频率特性,对自行研制的盘式触发三电极电晕稳定开关的工作特性进行了实验研究,并分析了实验结果。结果表明,在空气状态下,开关具有良好的触发特性,开关抖动和导通时延最小可以分别控制在4, 36 ns;同时,还可以通过减小触发间隙,进一步减小开关的导通时延和增加开关的稳定性。     

Transport properties and magnetoresistance in La0.8Te0.2MnO3/ZrO2 composites

The transport properties and magnetoresistance of electron-doped manganate / insulator composites (La_0.8Te_0.2MnO₃)_{1 - x}/(ZrO₂)_x (x=0, 0.3, and 0.5) are investigated. It is found that the metal-insulator transition temperature of this system shifts to a lower value as the ZrO₂ content increases. The introduction of ZrO₂ enhances both the domain scattering and electron relative scattering in the metal transport region. In the adiabatic small polaron hopping transport region, the thermal activation energy seems invariable regardless of the ZrO₂ content. The application of a magnetic field promotes the charge transportation capabilities of the composites, and the magnetoresistance is enhanced with an increase of the ZrO₂ content. This could be attributed to the more remarkable modification effect of magnetic field on ordering degree in the composites than in pure La_0.8Te_0.2MnO₃.     

Omni-directional mirror for visible light based on one-dimensional photonic crystal

The omni-directional reflection characteristics of one-dimensional photonic crystals composed of Ta 2 O 5 /MgF 2 multi-quantum well (MQW) are studied using the transfer matrix method. An omni-directional reflector consisting of three and four Ta 2 O 5 /MgF 2 MQWs is investigated. Results show that the photonic band gap of the photonic crystal composed of three and four Ta 2 O 5 /MgF 2 MQWs, which are within the wavelength ranges of 402–712 and 412–1,023 nm, respectively, could cover the entire visible region. The relationship among the width of the band gap, its location, reflectivity rate, and incident angle of the incident light is analyzed. The optimal structural parameters of the MQW of the omni-directional reflector in the visible region are also calculated. The calculations provide a guide for the design of omni-directional reflection devices in the visible region.     

Growth of SnO2 nanoparticles via thermal evaporation method

Tin oxide (SnO₂) nanoparticles were fabricated by evaporation of Sn powers at 1000 °C in air pressure. The as-deposited SnO₂ particles were single crystal structure, which were mostly spherical shape, the diameter of particles was ranging from 200 to 600 nm. The photoluminescence (PL) spectrum showed that a sharp emission peak at around 393 nm with the excitation wavelength at 325 nm, which suggested possible applications in nanoscaled optoelectronic devices. It was also found that the holding time affects the morphology of the products. The formation mechanism of SnO₂ particles was discussed.     

Beam controller using nonlinear embedded optical transformation

Flexible and adjustable beam splitters, expanders/compressors and the cloak are presented based on a universal two-dimensional transformation formula for the embedded transformation optics. Nonlinear transformation results by the suggested formula under different conditions reveal several interesting phenomena and potential applications. All beam controllers are achieved by the nonlinear coordinate transformation.     

Phase-change behavior in Si/Sb80Te20 nanocomposite multilayer films

Phase-change behavior in Si/Sb₈₀Te₂₀ nanocomposite multilayer films were investigated by utilizing in situ resistance measurements. It was found that the crystallization temperature increased firstly with increasing Si layer thickness within the multilayer films, and then remained almost unchanged at 170°C. The multilayer films have the merits of both good thermal stability and fast phase-change speed. An increase in crystallization temperature by around 95°C was observed for the multilayer films when the Sb₈₀Te₂₀ layer thickness was reduced to 3 nm. Cross-sectional transmission electron microscopy (TEM) observations revealed that Si/Sb₈₀Te₂₀ nanocomposite multilayer films had layered structures with clear interfaces. The reversible phase change between set and reset states was verified in phase-change random access memory (PCRAM) cell based on [Si (1 nm)/Sb₈₀Te₂₀ (5 nm)]₁₇ multilayer film.