单层膜体吸收与界面吸收研究

采用热透镜测量方法进行了SiO₂和HfO₂单层膜的体吸收与界面吸收分离研究.首先推导了光从薄膜侧及基底侧入射时单层膜内的驻波场分布,给出了单一厚度薄膜分离体吸收和界面吸收的计算方程式以及求解薄膜消光系数的方法.利用电子束蒸发工艺制备了半波长光学厚度(λ=1064 nm)的SiO₂和HfO₂单层膜,通过热透镜的测量数据实际分离了两种薄膜的体吸收和界面总吸收.计算结果表明,对于吸收小至10^{-6关键词： 驻波场理论 光热技术 薄膜吸收 消光系数}     

基于PSO优化LSSVM的未知模型混沌系统控制

由于混沌系统存在非线性、不确定性等特点, 常规的控制方法难以获得满意的结果. 提出一种基于PSO优化LSSVM模型参数的混沌系统控制方法. 该方法利用PSO算法的收敛速度快和全局收敛能力, 优化LSSVM模型的惩罚因子和核函数参数, 避免了人为选择参数的盲目性, 提高了LSSVM模型的预测精度. 另外, 该方法不需要被控混沌系统的解析模型, 且当测量噪声存在情况下控制仍然有效. 仿真实验结果表明了该方法的有效性和可行性. 关键词： 混沌系统控制 粒子群算法 最小二乘支持向量机     

基于时间控厚离子束溅射技术的宽带减反膜制备

 为了制备满足设计要求的宽角度、宽波段减反膜,利用离子束溅射沉积技术,在时间-功率控厚的模式下,对膜层沉积速率进行了精确修正。在实验中,利用时间-功率控厚的离子束溅射沉积技术,选择HfO₂和SiO₂作为高低折射率组合,在超抛ZF6玻璃基底上制备了宽角度、宽带减反膜,通过对实验后的透过率光谱曲线的数值反演计算,获得膜层厚度修正系数,初步得到了沉积速率随沉积时间变化的规律。利用修正后的沉积参数制备设计的膜系,在0°~30°入射角度下,600~1 200 nm波段的平均透过率达到99%以上。     

制备铋靶的脉冲电镀工艺

 采用脉冲电镀工艺,以直径为1 mm的铜丝为芯轴,在无氰镀液体系中,制备出惯性约束聚变实验用铋靶所需的金属铋镀层。通过正交试验得到的最佳脉冲工艺条件为：电流密度5 A/cm²,频率600 Hz,占空比1∶6,温度20 ℃。利用扫描探针显微镜和扫描电子显微镜分别对铋镀层表面形貌进行分析,同时利用X射线衍射对铋镀层物相成分进行分析。表征结果表明：所得铋镀层表面细致均匀,孔隙率低,平整性好,无裂纹。     

X波段高功率微波TE11模圆极化器

 基于圆波导TE₁₁模的模式简并特性和微波在椭圆波导中传输两个正交TE11模式相速不同的性质,研制了一种带有椭圆波导结构的圆波导TE₁₁模圆极化器。该圆极化器通过圆波导到椭圆波导的过渡段,将输入的线极化TE₁₁模式分成两个等幅、正交的TE₁₁模,然后调整椭圆波导长度,使得两个正交的TE₁₁模式的相位差为90°,实现了TE₁₁模式微波线极化到圆极化的转换。利用时域有限差分软件优化设计了该圆极化器,并按照优化的结构尺寸加工了一套实验装置进行了实验测试,测试结果表明：在工作频率9～10 GHz范围内,该圆极化器轴比小于1 dB,驻波比小于1.1,且功率容量大于1.6 GW。     

紫外-可见宽光谱显微成像光学系统的设计

 介绍一个紫外-可见宽光谱显微物镜的设计过程。通过改进的PW法求解初始结构参数,确定采用两个分离的正负透镜组组成透射式光学系统,根据光学材料的色散特性,选取正透镜材料为CaF2,负透镜材料为熔石英,通过建立复消色差方程组来分配双分离透镜的光焦度,合理地对两组透镜的偏角进行分配。运用CODE-V光学设计软件对系统进行优化,使系统的位置色差和二级光谱同时得到校正,实现了复消色差。仿真结果表明：系统在整个视场范围内,点列图弥散圆RMS半径值小于5  ,最大视场处的像散为0.058,畸变为0.04 %。     

Ratcheting and wrinkling of tubes due to axial cycling under internal pressure: Part II analysis

Part I presented a set of experiments in which pressurized tubes were cycled axially under stress control about a compressive mean stress. This loading history causes biaxial ratcheting involving compressive axial strain and expansion of the diameter of the tube. The compressive strain in turn induces the initiation and growth of axisymmetric wrinkles. Persistent cycling resulted in localization of the wrinkles and collapse. In Part II the problem is first modeled as a shell with initial axisymmetric imperfections while the biaxial ratcheting of the material is modeled using the Dafalias–Popov two-surface nonlinear kinematic hardening model. It is demonstrated that when suitably calibrated this modeling framework reproduces the prevalent ratcheting deformations and the evolution of wrinkling including the conditions at collapse accurately for all experiments. The calibrated model is then used to evaluate the ratcheting behavior of pipes under thermal-pressure cyclic loading histories experienced by axially restrained pipelines.     

A simple and efficient sample preparation for taxanes in Taxus chinensis needles with natural menthol‐based aqueous deep eutectic solvent

Taxanes are natural anticancer constituents, and the sample preparation from matrix normally depends on organochlorine solvents. In this study, green and natural menthol‐based aqueous deep eutectic solvent was synthesized and used for sample preparation for taxanes. Five key parameters were optimized and the optimal preparation conditions were as follows: menthol/1‐propanol ratio 1:1 (mol/mol), solid–liquid ratio 1:30 g/mL, extraction time 30 min, ultrasonic power 250 W, and water content 80%. Under the above conditions, the total extraction efficiency of seven main taxanes was 1.25‐ to 1.44‐fold to the conventional methods. In addition, a high‐performance liquid chromatography method with C₁₈ column was established for quantitation of seven main taxanes in <25 min, which had excellent linearity (R² > 0.9986), precision (relative standard deviation < 3.00%), repeatability (relative standard deviation < 3.69%), and recovery (90.26–109.00%). This method performed the extraction, and enrichment processes simultaneously, and it had advantages such as high extraction efficiency, simple operation, low cost, and eco‐friendliness. This work indicated that the natural menthol‐based deep eutectic solvent aqueous could be an excellent alternative to the sample preparation from Taxus or other plants.     

Synthesis,bioactivities and 3D-QSAR of novel avermectin B2a aglycon derivatives

Fourteen avermectin B2 a aglycon derivatives were designed and synthesized after removing the oleandrose disaccharide of avermectin B2 a.Their structures were characterized by’H NMR,13 C NMR,HMRS.Preliminary bioassays indicated that these compounds exhibited good insecticidal activity against diamondback moth at 200 mg/L,with mortality no less than 90%.Compounds 10 b,12 a,12 c,17 demonstrated good acaricidal activity against the adult mites,larvae,and good inhibition rate of hatching to mite eggs of Tetranychus cinnabarinus.Compounds 5,10 b,10 c exhibited excellent fungicidal activity against fourteen fungal pathogens in vitro.3 D-QSAR analysis showed that the fungicidal activity of avermectin B2 a aglycon derivatives would be increased when a negatively charged and bulky group was introduced at 13-position,which will be instructive for the further modification of avermectin B2 aaglycon.     

Influence of isopropyl tris(dioctylphosphoryloxy) titanate for flame-retardant TPU based on oyster shell powder

The flammability and droplet properties of thermoplastic polyurethane (TPU) have limited its wide application in many fields. In this article, isopropyl tris(dioctylphosphoryloxy) titanate was selected as synergism and compatilizer with oyster shell powder as flame retardant in TPU composites. And the influence of isopropyl tris(dioctylphosphoryloxy) titanate for flame-retardant TPU composites has been intensively investigated using the smoke density test, the cone calorimeter test, and the thermogravimetric analysis/infrared spectrometry, respectively. The test results show that isopropyl tris(dioctylphosphoryloxy) titanate can reduce the smoke production and heat release. And the total smoke production was reduced by 32% when the mass fraction of isopropyl tris(dioctylphosphoryloxy) titanate was 0.1%. The above results indicate that isopropyl tris(dioctylphosphoryloxy) titanate has a good application prospect in reducing the risk of TPU combustion.