All-fiber ring-cavity based frequency swept laser source for frequency domain OCT

<正>We develop a high-speed tunable,quasi-continuous-wave laser source for frequency domain(FD) optical coherence tomography(OCT).The laser resonance is realized within a unidirectional all-fiber ring cavity consisting of a fiber coupler,two fiber isolators,a semiconductor optical amplifier(SOA),and a fiber FabryPerot tunable filter(FFP-TF) for frequency tuning.Light output from the coupler is further amplified and spectral shaped by a booster SOA terminated at both ends with two isolators.The developed laser source provides up to 8000 sweeps per second over a full-width wavelength tuning range of 120 nm at center wavelength of 1320 nm with an average power of 9 mW,yielding an axial resolution of 13.6μm in air and a maximum sensitivity of about 112 dB for OCT imaging.The instantaneous linewidth is about 0.08 nm,enabling OCT imaging over an axial range of 3.4 mm in air.For optimization consideration based on this custom-built swept laser,experimental study on imaging quality relevant parameters of the swept laser with sine and ramp driving waveforms to the FFP-TF is conducted,and investigation of the swept laser on the cavity length is done.Implementing the laser source in our established swept source based OCT(SS-OCT) system,real-time structural imaging of biological tissue is demonstrated.     

Synthesis,characterization and electrochemical impedance spectroscopy of VOx-NTs/PPy composites

Composites consisting of vanadium oxide nanotubes (VOx-NTs) and polypyrrole (PPy) were synthesized by a two-steps method. VOx-NTs were firstly prepared by a combined sol–gel reaction and hydrothermal treatment procedure, in which V ₂O₅ powder and H₂O₂ were used as raw materials and hexadecylamine as a structure-directing template. Then VOx-NTs/PPy composites were fabricated by a cationic exchange reaction between hexadecylamine and polypyrrole. The structure and morphology of the samples were investigated by SEM, TEM, XRD and FTIR techniques. The results confirmed that the template molecules were successfully substituted by the conducting polymers PPy without destroying the previous tubular structure. Electrochemical impedance spectroscopy (EIS) measurements were performed to evaluate the electrochemical kinetics of the samples. The results indicated that VOx-NTs/PPy composites had a lower charge transfer resistance and a faster lithium-ion diffusion speed than those of VOx-NTs, and the enhanced electrochemical kinetics could be attributed to the excellent electronic conductivity of polypyrrole.     

单位圆内二阶线性微分方程的解与小函数的关系

讨论了系数是单位圆内解析函数的二阶齐次和非齐次线性微分方程的解及其一阶导数和二阶导数与小函数之间的关系,并得到了它们之间的精确估计.     

环境水体中铅的快速测定方法研究

研究在六次甲基四胺缓冲溶液的介质中,乙醇存在下,铅与甲基百里香酚蓝的快速显色反应体系。显色反应生成一种蓝色络合物,其最大吸收波长为605nm。在优化的实验条件下,铅含量在0—10.0mg·mL-1范围内符合比耳定律,方法检出限为0.2mg·mL-1。对实际样品进行分析,结果令人满意。     

Uniqueness Theorem of Meromorphic Mappings with Moving Targets

Some uniqueness theorems of meromorphic mappings with moving targets are given under the inclusion relations between the zeros sets of meromorphic mappings.     

飞行事故的一种自适应模糊神经网络预测方法研究

飞行事故预测对于预防飞行事故具有十分重要的意义.首先系统分析了空军飞行事故的主要影响因素,对其中的定性因素进行了量化;然后利用系统分析的成果和历史统计数据建立了空军飞行事故的自适应模糊神经网络预测模型.整个预测过程突破了纯数学模型预测的局限性,实现了预测的定性和定量的结合;由于预测中使用了一种基于高木.关野模糊模型的自适应模糊神经网络,从而使预测模型具有很强的自适应能力,预测结果也比较令人满意.     

Optical and Short- wavelength Recording Properties of Ag_8In_( 14) Sb_( 55) Te_(23) Phase-change Films

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｏｐｔｉｃａｌｄａｔａｓｔｏｒａｇｅｂｙｍａｒｋｉｎｇｏｆｍｉｃｒｏｎ ｓｉｚｅｄｓｐｏｔｓｏｎａｄｉｓｋｗｉｔｈａｌａｓｅｒｉｓａｎａｒｅａｗｉｔｈｏｎｇｏｉｎｇｒｅｓｅａｒｃｈａｃｔｉｖｉｔｙ .Ｏｐｔｉｃａｌｄｉｓｋｄａｔａｓｔｏｒａｇｅｈａｓｔｈｅｃｏｍｂｉｎｅｄａｄｖａｎｔａｇｅｓｏｆｈｉｇｈｓｔｏｒａｇｅｄｅｎｓｉｔｙ ,ｄｉｓｋｒｅｍｏｖａｂｌｅ,ａｎｄｌａｒｇｅｈｅａｄ ｄｉｓｋｗｏｒｋｉｎｇｄｉｓｔａｎｃｅ.Ｉｎｒｅｃｅｎｔｙｅａｒｓ ,ｗｒｉｔｅ ｏｎｃｅ…     

超快调制光谱术

简述超快调制光谱学在近向年的研究状况，其对能级差的测量精度决定于光学跃迁的均习增宽。在符合折频条件时，两独立光源拍频的差可以超出激光红宽，激光绝对频率的测量精度可以达到与激光红宽同一量级。     

纳米累托石-TiO2粉末光催化降解染料废水

用纳米累托石-TiO2粉末作催化剂，在紫外灯光下降解甲基橙溶液．考察了甲基橙溶液的pH值、初始浓度、纳米累托石-TiO2投加量对甲基橙降解率的影响．比较了相同条件下制备的纳米累托石-TiO2和纳米TiO2粉末及P25TiO。粉末的光催化活性．实验结果显示：在紫外灯光照射下，纳米累托石-TiO2，纳米TiO2粉末及P25降解甲基橙30min，降解率分别为：92．9％，50．9％，96．5％．在相同条件下制备的纳米累托石-TiO2粉末比纳米TiO2粉末具有更高的催化活性，接近当今催化活性最高的P25催化剂．