聚焦光在亚表面损伤介质中的散射特性

针对光学元件的亚表面缺陷,结合基于激光共焦层析的亚表层检测方法,建立聚焦光束在亚表面损伤介质中的传输模型,并采用有限元分析方法,仿真研究K9玻璃光学元件亚表层缺陷对聚焦光束的散射调制特性,特别对颗粒状和微裂纹两类特殊缺陷的光学调制特性进行研究和分析,探索了波长、缺陷大小、缺陷折射率及缺陷方向对聚焦光束散射特性的影响规律,通过分析包含亚表面损伤缺陷信息的光场分布图和强度变化曲线,获得了亚表面损伤缺陷的信息,并对其进行评价。     

High refractive index sensitivity sensing in gold nanoslit arrays

The extraordinary optical transmission(EOT) phenomenon of nano-periodic aperture array in metallic film has been widely investigated and used in biosensors. The surface plasmon resonance and cavity mode in some periodic nanostructures, such as nanohole and nanoslit, cause EOTs at certain wavelengths. This resonance wavelength is sensitive to the refractive index on the surface of periodic nanostructures. Therefore, the metallic nanostructures are expected to be good sensing elements. The sensing performances of gold nanoslit arrays are experimentally and theoretically investigated.Three-dimensional finite difference time domain(FDTD) simulations are utilized to explore their transmission spectra and steady-state field intensity distributions. The electron beam evaporation, electron beam lithography, and ion milling are applied to the gold nanoslit arrays with different widths and periods. The sensing performances of the gold nanoslit array are characterized via transmission spectra in four kinds of refractive index samples. The highest sensitivity reaches726 nm/RIU when the width of the gold nanoslit array is 38.5 nm.     

怎样巧解填空题

填空题在高考试卷中,不仅具有题目数量多,占分比例高的特点,而且还具有知识覆盖面宽,能力立意高,思维容量大,小巧灵活,解法多样等特点.如何使考生准确、快捷地解好填空题,是高三数学复习中必须精确指导和强化训练的一个重要内容.本文介绍直接法、等价转换法、特殊值法、数形结合法、极限法来解析巧解填空题的五种常用方法,供复习时参考...     

碳纳米管在分离科学中的应用研究进展

碳纳米管(CNTs)作为一种新型纳米材料已在材料、催化、吸附分离等诸多领域得到了广泛的应用。本文对近年来CNTs在分离科学中的应用研究进展进行了简要评述,主要讨论了CNTs在固相萃取、固相微萃取、膜萃取、色谱固定相和毛细管电泳假固定相等方面的应用。     

电感耦合等离子体发射光谱法测定古墓土壤样品中铜、铅、锌、铁

样品经氢氟酸-盐酸-硝酸-高氯酸混合酸溶解,在φ为5％的硝酸介质中,用电感耦合等离子体发射光谱法测定古墓土壤样品中的铜、铅、锌、铁,克服了传统分析方法步骤冗长、过程难以控制等缺点.方法检出限为:铜2.0 μg/g,铅3.0μg/g,锌2.0μg/g,铁10 μg/g,精密度(RSD,n=12)在1.5％～12.0％.方...     

Concentration and Temperature Dependences of YBO3：Bi^3＋ Luminescence under Vacuum Ultraviolet Excitation

Bi^3＋ doped YB03 phosphors are prepared by solid state reaction and their luminescent properties are investi- gated by using synchrotron radiation instrument, Concentration and temperature dependences of YBO3：Bi3＋ luminescence under VUV/UV excitation is observed, The emission and excitation spectra are assigned, and the mechanism for these phenomena is explored, which result from the energy transfer between Bi^3＋ ions occupying different sites in YB03 crystal lattice.     

A Single-Fundamental-Mode Photonic Crystal Vertical Cavity Surface Emitting Laser

Single-fundamental-mode photonic crystal （PhC） vertical cavity surface emitting lasers （VCSEL） are produced and their single-fundamental-mode performances are investigated and demonstrated. A two-dimensional PhC with single-point-defect structure is fabricated using UV photolithography and inductive coupled plasma reactive ion etching on the surface of the VCSEL＇s top distributed Bragg-reflector. The PhC VCSEL maintains single-fundamental-mode operating with output power 1.7 mW and threshold current 2.5 mA. The full width half maximum of the lasing spectrum is less than 0.1 nm, the far field divergence angle is less than 10° and the side mode suppression ratio is over 35 dB. The device characteristics are analyzed based on the effective index model of the photonic crystal fiber. The experimental results agree well with the theoretical expectation.     

多障碍物通道中激波诱导气相爆轰的数值研究

应用数值模拟方法,研究了直通道中激波经过多块矩形障碍物时诱导 H2/O2混合气体起爆的物理机制. 研究表明：在前导激波强度不足以诱导波后气 体直接起爆的条件下,经过激波压缩的可燃气体也可能在远离激波的障碍物之间的凹槽部位 起爆;障碍物表面产生的压缩波、膨胀波和气流滑移面对可燃气体的起爆、爆轰波的形成和 传播过程有重要的影响;添加不同稀释比的氮气可以影响爆轰波后流场的温度分布;增加障 碍物的间距可以改变可燃气起爆位置.     

不同表面结构的金纳米粒子荧光性质.

"研究了具有不同表面结构的金纳米粒子：裸金纳米粒子、三苯基膦修饰的金纳米粒子、巯基丙酸表面取代的金纳米粒子的荧光性质,及其对CdSe纳米粒子的荧光猝灭作用．发现不同的金纳米粒子荧光信号受粒子表面一价金离子与配体分子之间相互作用的影响,其荧光强度对其表面分子具有强烈的敏感性;具有不同表面结构的金纳米粒子对CdSe纳米粒子的荧光猝灭作用不同,与其吸收光谱和CdSe纳米粒子发射光谱的重叠程度相关."