Investigation of a UV-laser generated planar polymeric waveguide directly and after five years of preparation using an interferometric method

Polymeric integrated-optical waveguides were prepared in a planar chip using UV-laser lithographic method. Five waveguide samples were irradiated by an excimer laser of wavelength 248 nm with different irradiation parameters (fluence and irradiation doses). Using Mach–Zehnder interferometer, the refractive index depth profiles of these samples are determined in two cases, directly and five years later of preparation. A crucial change of refractive indices profiles has been recorded after five years of preparation. In the first case we got double region waveguides fitted a Gaussian shape, while in the second one we observe a single region waveguide which has exponential shape. The photochemical reactions responsible for these changes in the two cases are demonstrated. This is quite important when such waveguides are used in the applications. Also it was interesting to investigate the aging impact on mode field distributions and the effective mode indices. The mode parameters are determined based on a theoretical model and the experimentally obtained data. The results show a notable change in the mode field distributions and the propagation coefficients as influence of aging.     

基于可口可乐荧光和滤光特性的光谱学实验

通过荧光光谱仪,确定可乐的弱荧光物质和滤光特性,对532nm激光激发的红移现象进行解释.自组微调夹持转向装置,利用教学用光栅单色仪定量研究了激光与可乐作用深度对光谱的影响.实验结合了荧光光谱和物质滤光特性等知识,物理内涵丰富,可通过自组实验装置锻炼学生解决实际问题的能力.     

Optical depth of traps in AL2O3:C determined by the variable energy of stimulation OSL (VES-OSL) method

Standard methods of OSL measurements (CW-OSL or LM-OSL) do not allow for the direct determination of optical depth of traps. The variable energy of stimulation optically stimulated luminescence (VES-OSL) method gives such possibility. It consists in optical stimulation with the continuous increase of stimulation light energy and is analogous to the glow curve method in TL measurements. The VES-OSL curve shape and maximum position can be regulated by the stimulation photon flux, the rate of stimulation energy increase and by measurement temperature. This allows for detecting the OSL from very deep traps that give the TL signal overlapping with strong incandescence. The VES-OSL measurements carried out for Al₂O₃:C showed that traps having the optical depth between 2.0 and 2.8 eV are responsible for the OSL signal related to TL peak at about 200 °C. The OSL signal from the much deeper traps from the range 2.8–3.3 eV was also detected. The TL signal related do these traps cannot be detected below 500 °C.     

ToF-SIMS depth profiling of oral drug delivery films for 3D visualization of active pharmaceutical particles

The size, shape, and spatial distribution of active pharmaceutical ingredient (API) are important physical characteristics of drug delivery systems that can affect the performance, stability, appearance, and even bulk properties of the end product. This study explores the feasibility of using time-of-flight secondary ion mass spectrometry (ToF-SIMS) for the 3D characterization of API particles in two commercially available oral dissolvable drug delivery films. It was found that ToF-SIMS imaging with argon gas cluster ion beam (GCIB) sputtering allowed production of 3D chemical maps that could be utilized to obtain size distributions of buprenorphine particles whose effective diameters ranged from approximately 6 μm to 41 μm, with shapes that were generally spherical with a few nonspherical structures. The particles were heterogeneously distributed both laterally and as a function of depth in the film. In addition, ToF-SIMS was able to differentiate between different oral drug delivery films based on differences in the spatial distribution of buprenorphine; in one case, the particles were distributed throughout the depth of the film, whereas the particles in the other case were localized close to the surface. Preliminary studies suggest that ToF-SIMS with argon GCIB sputtering may also allow us to provide a very rough estimate of the concentration of the APIs (factors of 2 to 4), namely buprenorphine and naloxone, at pharmacologically relevant concentrations inside organic drug delivery systems with a thickness of hundreds of micrometers.     

Epidermal Electronic Systems for Measuring the Thermal Properties of Human Skin at Depths of up to Several Millimeters

Monitoring the composition, blood flow properties, and hydration status of human skin can be important in diagnosing disease and tracking overall health. Current methods are largely limited to clinical environments, and they primarily measure properties of superficial layers of the skin, such as the stratum corneum (10–40 µm). This work introduces soft, skin‐like thermal depth sensors (e‐TDS) in designs that seamlessly couple with human skin and measure its thermal properties with depth sensitivity that can extend up to 6 mm beneath the surface. Guidelines for tailoring devices to enable measurements through different effective depths follow from a systematic set of experiments, supported by theoretical modeling. On‐body testing validates the physiological relevance of measurements using the e‐TDS platform, with potential to aid the diagnosis of deep cutaneous and systemic diseases. Specific demonstrations include measurements that capture responses ranging from superficial changes in skin properties that result from application of a moisturizer, to changes in microvascular flow at intermediate depths induced by heating/cooling, to detection of inflammation in the deep dermis and subcutaneous fat in an incidence of a local bacterial infection, cellulitis.     

Single depth map super-resolution via joint non-local self-similarity modeling and local multi-directional gradient-guided regularization

The development of consumer depth cameras makes it possible to acquire depth information of a scene in real-time. However, low resolution and low quality of a depth map has greatly constrained its applications. In this paper, we propose a novel framework for single depth map super-resolution, which considers local and non-local information jointly in the depth map. For the non-local constraint, group-based sparse representation is used to explore non-local self-similarity in the depth map. For the local constraint, a multi-directional gradient-guided regularization is proposed to describe the gradient of the depth map with spatially varying orientations. The former constraint contains the visual artifacts effectively, while the latter restores sharp edge and fine structure. Finally, the two complementary regularizers are jointly casted into a unified optimization framework, where a split Bregman-based technique is developed to tackle the optimization problem. Both quantitative and qualitative evaluations indicate that the proposed method can obtain better reconstruction performance compared with state-of-the-art methods.     

侵彻引信炸点精确控制技术

为了实现侵彻弹药的高效毁伤,硬目标侵彻引信必须完成最佳炸点识别和起爆控制任务。对比研究了两类炸点精确控制方案:一类是基于侵彻深度经验公式,另一类是基于侵彻引信记录装置中的高g值加速度计测量信息。前者的精度完全依赖于先验信息,而后者的精度则取决于冲击加速度的精确测量和控制算法的实时解算。给出了基于伪自相关的空穴识别算法。冲击加速度信号自乘实现调频脉冲压缩,再通过低通滤波即可提取出平滑的侵彻信号包络线。进一步,详细推导了实时计算侵彻深度的积分算法。利用数学仿真的侵彻两层钢靶和实测的侵彻五层混凝土靶冲击加速度进行了算法验证。空穴识别算法能够准确识别出侵彻介质的层数,而冲击加速度的双积分与弹体实际位移保持一致,相对误差约3%。     

时域Rankine源法求解有限水深船舶在规则波中的水底压力变化

应用势流理论中的Rankine源面元法和时域步进法,求解了有限水深船舶在规则波中运动的水底压力变化。将速度势分解成基本势、局部势和记忆势,以叠模解作为基本势对自由表面条件和物面条件进行了线性化,通过在水底布置面元来满足水底条件。利用研制的水底压力-水面波浪测量系统,测量了不同入射波船模表面波形与水底压力的时历曲线,理论计算与实验结果符合较好,验证了自编程序的正确性。通过对比二者的等高线图发现,水底压力与表面波形的峰谷有较好的一致性,并且压力较波形更为平滑。     

利用深度探测函数研究双层介质的空间分辨漫反射率

提出了一种研究双层介质空间分辨漫反射率的理论模型。考虑到不同深度分布的光子对探测信号的贡献不同,引入深度探测函数a(z,p),用其描述探测光子与散射介质空间面的相互作用,进而提出了一种研究双层散射介质空间分辨漫反射率的理论方法。给出了双层散射介质的空间分辨漫反射率的理论分析结果,并与Monte Carlo模拟结果进行比较,结果表明两者符合得较好。