混凝土作为典型的多孔介质材料，其扩散性能与内部孔隙结构密切相关。考虑到孔隙结构会随水泥水化过程不断变化，因此有必要提出一种基于时变孔隙结构的扩散性能预测模型。基于重构的水泥浆体微观结构，本研究开展了孔隙结构的参数化分析、非饱和状态水分分布模拟以及不同饱和度下浆体组分相对扩散系数的预测和验证。综合预测的相对扩散系数和提取的孔隙参数(水化程度α、孔隙率ρ和无量纲的峰值孔径B*)，进一步系统分析了α与时间t、ρρQUOTE与α以及B*与ρ相互间的关系，并最终建立了包含时变参数f(α(t)，ρ(t)，B*(t))的非饱和混凝土扩散性能预测模型。此模型可以充分考虑混凝土孔隙结构受不同水灰比和水化时间影响的时变过程，为从变化的孔隙结构角度研究非饱和混凝土的扩散性能提供了一个新的微观视角。

基于动态光散射原理，搭建了一套可测量热扩散系数的动态光散射系统，该实验系统包括散射光路、耐压实验本体、温度控制以及数据采集系统。同时，将光纤引入到动态光散射系统中作为探头，将实验系统缩小至类似系统的1/3。利用参考流体正己烷对实验系统进行了检验，将实验获得的热扩散系数拟合为多项式方程，拟合最大偏差为0.19%，平均绝对偏差为0.11%，与文献值最大偏差为3%。经过不确定度分析可知，所研制的动态光散射实验系统测量液体热扩散系数的不确定度为2%（k=2）。

提出了一种基于表面热透镜技术的热扩散率测量方法。利用脉冲泵浦光加热样品，热量沿膜层传导形成温度场，温升区域热膨胀形成表面热包，其对探测光具有调制作用，产生了表面热透镜效应。通过分析热透镜信号的相位与探测距离的关系，求出了对应泵浦光频率下的热扩散长度，进而求得热扩散率。测量了膜厚为150 nm的铬膜样品的热扩散率，所提方法的测量结果为36.9 mm²/s，与光热偏转法的测量误差仅为0.8%，与其他不同类型样品在两种方法下的测量结果也较为接近，证明了所提方法的有效性。相对于光热偏转法，所提方法具有装置简单、受环境影响较小等优点。

采用从头算分子动力学研究在不同温度(300?K,700?K,1?000?K,1?200?K)下氢原子在α-石英中的扩散机制，根据爱因斯坦方程计算氢原子的扩散前项因子D0(7.72×10-4?cm2/s)和活化能(0.078?eV)。研究结果表明，氢原子在α-石英中的扩散路径有2种。低温下氢原子主要在由硅和氧原子组成的腔中做随机运动，直到跨过一个环到另外一个腔。同时研究温度在1?500?K时氢原子的扩散，氢在周围的3 个氧原子之间发生跳跃，导致扩散过程中出现了3种缺陷结构，缺陷结构之间可以相互转化。本文研究在微电子器件可靠性分析等方面有应用价值。

为研究氧化剂和还原剂的配比对四氧化三铅/镁粉/聚四氟乙烯(Pb3O4/Mg/PTFE)混合诱饵剂效能的影响，保持氧化剂的配方不变，改变氧化剂和还原剂的比例，设计了5种不同的药剂配方。使用压片机将混合均匀的药剂粉末压制成药柱。用7.5~14 ?滋m远红外热像仪测量药柱燃烧过程，计算出每个样品的燃烧时间、质量燃速、辐射面积、辐射亮度、辐射强度。结果表明: 随着还原剂的比例升高，样品质量燃速先变大后变小，当氧化剂与还原剂比例为1:1时，质量燃速最大，为5.03 g/s; 样品燃烧的温度随着还原剂的比例升高先变高后降低，当氧化剂: 还原剂=1:2时，样品燃烧的最高温度达到最小，为754.29 ℃; 辐射亮度和强度随着还原剂的比例升高先变大后变小，且当氧化剂: 还原剂=1:1时，辐射亮度最大，为1 869.21 W·m-2·sr-1，辐射强度也达到最大，为97.61 W·sr-1，可见在7.5~14 ?滋m波段，当氧化剂: 还原剂=1:1时，样品的远红外辐射特性最好。

提出了一种四层光热辐射模型，研究了编织碳纤维增强聚合物(CFRP)的热扩散系数。以玻璃碳为参考材料，标定了实验装置，完成了孔隙率为0~18.32%的14组CFRP样品的检测实验。构造了最小二乘目标函数，利用遗传算法求出了最优解，得到了不同孔隙率下的CFRP热扩散系数。结果表明，14组CFRP样品的热扩散系数为3.01×10-7~8.73×10-7 m2/s，且随着孔隙率的增大整体呈下降趋势；当孔隙率小于1.00%时，热扩散系数的下降趋势较明显，但当孔隙率大于1.00%后，下降速度趋于平缓。

Optical immersion clearing is a technique that has been widely studied for more than two decades and that is used to originate a temporary transparency effect in biological tissues. If applied in cooperation with clinical methods it provides optimization of diagnosis and treatment procedures. This technique turns biological tissues more transparent through two main mechanisms — tissue dehydration and refractive index (RI) matching between tissue components. Such matching is obtained by partial replacement of interstitial water by a biocompatible agent that presents higher RI and it can be completely reversible by natural rehydration in vivo or by assisted rehydration in ex vivo tissues. Experimental data to characterize and discriminate between the two mechanisms and to find new ones are necessary. Using a simple method, based on collimated transmittance and thickness measurements made from muscle samples under treatment, we have estimated the diffusion properties of glucose, ethylene glycol (EG) and water that were used to perform such characterization and discrimination. Comparing these properties with data from literature that characterize their diffusion in water we have observed that muscle cell membrane permeability limits agent and water diffusion in the muscle. The same experimental data has allowed to calculate the optical clearing (OC) efficiency and make an interpretation of the internal changes that occurred in muscle during the treatments. The same methodology can now be used to perform similar studies with other agents and in other tissues in order to solve engineering problems at design of inexpensive and robust technologies for a considerable improvement of optical tomographic techniques with better contrast and in-depth imaging.

利用红外热成像技术，研究了编织碳纤维复合材料（CFRP）在纤维束编织平面内的热传导规律。根据激光调制加热原理，推导了纤维束平面内热扩散系数和相位梯度的关系，并搭建了相应的实验平台，对CFRP试件进行实验。以玻璃碳作为参考材料，将测得的红外辐射相位信号进行规格化处理，并利用高斯滤波去除红外热图像的噪声。实验结果表明，碳纤维复合材料的各向异性使其在纤维束编织平面各方向上的热传导呈现一定的规律，且与传导方向相关。当激光调制频率小于2 Hz时，可以测量得到CFRP试件在平面不同方向上的热扩散系数。

With the objective to study the variation of optical properties of rat muscle during optical clearing, we have performed a set of optical measurements from that kind of tissue. The measurements performed were total transmittance, collimated transmittance, specular reflectance and total reflectance. This set of measurements is sufficient to determine diffuse reflectance and absorbance of the sample, also necessary to estimate the optical properties. All the performed measurements and calculated quantities will be used later in inverse Monte Carlo (IMC) simulations to determine the evolution of the optical properties of muscle during treatments with ethylene glycol and glucose. The results obtained with the measurements already provide some information about the optical clearing treatments applied to the muscle and translate the mechanisms of turning the tissue more transparent and sequence of regimes of optical clearing.