Numerical Analysis of Fiber Bragg Grating and Long Period Fiber Grating Undergoing Linear and Quadratic Temperature Change

The coupled-mode equations for fiber Bragg grating （FBG） and long period fiber grating （LPFG） undergoing linear and quadratic temperature change were given. The effects of temperature gradient and quadratic temperature change on the reflectivity spectrum of fiber Braggs grating and the transmission spectrum of long period fiber grating were investigated using the numerical simulation, and the dependence relationships of the central wavelength shift, the full-width-athalf-maximum, and the peak intensity upon temperature gradient were also obtained. These relationships may be used to design a novel fiber optical sensor which can simultaneously measure the temperature and temperature gradient.

Preparation of Magnetic Chitosan Nanoparticles and Immobilization of Laccase

The magnetic chitosan nanoparticles were prepared by reversed-phase suspension method using Span-80 as an emulsifier, glutaraldehyde as cross-linking reagent. And the nanoparticles were characterized by TEM, FT-IR and hysteresis loop. The results show that the nanoparticles are spherical and almost superparamagnetic. The laccase was immobilized on nanoparticles by adsorption and subsequently by cross-linking with glutaraldehyde. The immobilization conditions and charac-terizations of the immobilized laccase were investigated. The optimal immobilization conditions were as follows： 10 mL of phosphate buffer （0.1 M, pH 7.0） containing 50 mg of magnetic chitosan nanoparticles, 1.0 mg·mL-1 of laccase and 1% （v/v） glutaraldehyde, immobilization temperature of 4 ℃ and immobilization time of 4 h. The immobilized laccase exhibited an appreciable catalytic capability （480 units·g-1 support） and had good storage stability and operation stability. The Km of immobilized and free laccase for ABTS were 140.6 and 31.1 μM in phosphate buffer （0.1 M, pH 3.0） at 37 ℃, respectively. The immobilized laccase is a good candidate for the research and development of biosensors based on laccase catalysis.

Formation and Characterization of CdS Hollow Structures

CdS hollow structures were built up by using the one pot method and using carbon disulfide （CS2） and ethylenediamine as starting materials. CS2 is insoluble in water and could form metastable oil droplets in the water at a moderate temperature. The oil droplets formed chains in the circumvolving water. CdS crystals grew and mineralized on the surfaces of the CS2 droplet chains, forming CdS shells around the unreacted CS2 cores. After the surrounding temperature was raised above the boiling point of CS2, the unreacted CS2 cores vaporized, leaving the CdS shelled hollow structures. The CdS hollow structures were characterized by using a transmission electron microscope, an X-ray diffractometer, a UV-Visible spectrophotometer and a fluorescence spectrophotometer. The CdS hollow structures were mainly tubes with closed ends. The exterior diameter and the interior diameter of tubes were about 50 nm and about 15 nm, respectively. Compared with the absorption onset wavelength of the bulk CdS, the CdS hollow structures exhibited a blue shift of about 57 nm. While excited at 213 nm, the CdS hollow structures emitted greenish blue light centered at 470 nm.

Spectra and DNA-binding Properties of Two Novel Mixed-ligand Complexes Containing Organosulfonate

Two novel mixed-ligand complexes, [M（phen）2（ans）2]·H2O （M = Cd（Ⅱ） 1, Zn（Ⅱ） 2; phen is 1, 10-phenanthroline, and ans is 4-aminonaphthalene-1-sulfonate）, were obtained from the reaction of 1, 10-phenanthroline, sodium 4-aminonaphthalene-1-sulfonate tetrahydrate and acetate in mixed solvents. Interaction of the complexes with calf thymus DNA （ctDNA） were investigated using UV-vis absorption spectra, luminescence titrations, steady-state emission quenching by [Fe（CN）6]4 , DNA competitive binding with ethidium bromide （EB） and viscosity measurements. The experimental results indicate that there exist two interaction modes between the complexes and DNA, namely the electrostatic interaction and intercalation, with the binding constants of 1.82 × 10^5 M-1 for 1 and 4.78 ×10^4 M^- 1 for 2 in buffer of 50 mM NaCl and 5 mM Tris-HCI （pH 7.0）.

Design of an Enhanced Sensitivity FBG Strain Sensor and Application in Highway Bridge Engineering

紧张传感器被给，并且而且高取得资格，拉紧传感器的提高的敏感纤维栅栏(FBG ) 的理论设计方法被开发并且制作，谁的察觉到性质对实际应用程序好。有圆柱的壳封装的紧张传感器包含了三管状的结构，由于不平的表面结构，在紧张集中的区域，改进敏感。它能完成埋入紧张测量和表面测量并且有容易的安装的优点。好协议在大小和理论模拟结果之间被获得。在每刻度测试以后， 24 个 FBG 紧张传感器和六个 FBG 温度赔偿传感器在 Yongtaiwen 高速公路在 Diaoshuiyan 桥牌的盒子 girder 的下面上被安装了。最后，我们为高速公路桥建立了一个长期的结构健康系统。

Photorefractive Effect in a CdS Nanoparticlessensitized Polymer Composite

The photorefractive （PR） performance of an organic/inorganic hybrid polymer composite sensitized by CdS nanoparticles, combining poly（N-vinylcarbazole） （PVK）, the second-order optically nonlinear chromophore 1-n-butoxy-2-methyl-（4-p-nitropheylazo）benzene （BMNPAB） and 9-ethylcarbazole （ECZ） was studied. It was confirmed that the CdS colloidal particles had a nanoscale size and quantum confinement effect adopting transmission electron microscopy and UV-Vis absorption spectroscopy. The addition of CdS nanoparticles as a photosensitizer in PVK will be significant enhancement of photoconductivity because of the high photocharge generation quantum efficiency and high charge transport to conducting polymer. The polymer composite film exhibited PR effect with a method of two-beam coupling experiment. And an asymmetric two. beam coupling gain of 45.8 cm^-1 without applied electric filed is obtained at 632.8 nm wavelength.

Producing Regenerated Gratings in Hydrogen-Loaded Single Mode Fiber by Heat Treatment

纤维布拉格栅栏(FBG ) 是一个被动光纤维部件，折射索引沿着纤维长度调制了并且广泛地在察觉到系统的纤维被使用了。高温度的稳定的纤维栅栏为在高温度的使用是有希望的并且吸引广泛的注意。在这份报纸， FBG 在氢被刻写有 248-nm excimer 激光的装载标准单个模式纤维，和改革栅栏通过热处理被获得。改革 FBG 的中央波长的移动与改革 FBG 的温度，和反射率有好线性能几乎在 800 敨 ? 保持未改变 ? 猠牴吗？