The Second Order Guided Modes Based on Photonic Bandgap Effects in Air/Glass Photonic Crystal Fibers

We introduce a defect site in the periodic structure of a photonic bandgap fiber, to confine and guide the second order mode by photonic bandgap effects. Based on a high air-filling fraction photonic crystal cladding structure, a simplified model with an equivalent air cladding was proposed to explore and analyze the properties of this second order guided mode.     

射频溅射功率对FeZrBCu软磁合金薄膜巨磁阻抗效应的影响

用射频溅射法制备了FeZrBCu软磁合金薄膜.研究了不同溅射功率对FeZrBCu薄膜软磁特性和巨磁阻抗效应的影响.用电子探针显微镜测量发现，当溅射功率为240W时，薄膜样品中Fe的原子含量为8732%，Cu的原子含量为29%.这种样品的矫顽力最小，为68A/m，饱和磁化强度约为111×105⁵A/m，软磁性能最佳，巨磁阻抗效应最大，溅态膜在 13MHz最大巨磁阻抗比纵向为17%，横向为11%.重点分析了阻抗的电阻、电感分量及横向有 效磁导率随频率的变化，得到在低频下主要是磁电感 关键词： 铁基合金 薄膜 巨磁阻抗效应     

Highly Birefringent Honeycomb Photonic Bandgap Fibre

A new structure of highly birefringent honeycomb photonic bandgap fibres （PBGFs）, including an elliptical air hole in its solid core, is proposed and analysed by using full vectorial plane wave expansion method. From the numerical results it is confirmed that the proposed PBGF. has birefringence of the order of 10^-3. Moreover, there are two single-polarization single-mode ranges at varying normalized wavelength, in one of which only the slowaxis mode exists, and in the other only the fast-axis mode exists, which has not been achieved in index-guiding photonic crystal fibres so far.     

GaAs/GaAlAs traveling wave type laser amplifier with tilted facets

GaAs/GaAlAs traveling wave type laser amplifiers with different tilted angle facets are defined by proton bombardment. Some characters are measured. Maximum single-pass gains of 27.8 dB are reached with an optical fiber coupling system.     

聚苯乙烯/氧化铝复合物的合成与表征

近胶束聚合反应;十二烷基磺酸钠;苯乙烯;氧化铝;二乙烯苯     

Polarization-maintaining photonic crystal fibre

Photonic crystal fibres (PCFs) offer new possibilities of realizing highly birefringent fibres due to a higher intrinsic index contrast compared to conventional fibres. In this paper, we analyse theoretically the modal properties of a kind of polarization-maintaining PCF, namely the elliptical hole photonic crystal fibre (EHPCF) with a central small elliptical hole introduced in the core region. We demonstrate the possibility of achieving large birefringence with zero walk-off in the single-mode regime. This PCF also exhibits unusual dispersion properties. Several hundred nanometres of ultra broadband flattened dispersion near the wavelength 1.55μm is achieved in this EHPCF with a central small hole of d_c=0.4Λ.     

一种带葡萄柚空气孔的高双折射ZrF_4-BaF_2-LaF_3-AlF_3-NaF光子准晶光纤

提出了一种具有二重对称性的ZrF4-BaF2-LaF3-AlF3-NaF(ZBLAN)氟化物玻璃基的光子准晶光纤.光纤结构是以ZBLAN氟化物玻璃为背景材料,外包层由圆形空气孔以正方形与正三角形分布组成的基本单元构成,在芯区两侧引入两个对称的葡萄柚空气孔,以增加光纤的双折射.应用全矢量有限元法,研究了光纤的双折射和限制损耗特性与结构参数的关系.通过优化光纤结构参数,在1800—2200 nm的波长范围内获得了具有单模传输特性的高双折射光纤,其模式双折射高达10-2,比普通保偏光纤高出两个数量级,与目前报道的采用椭圆空气孔微结构光纤获得的高双折射具有同样的量级.但与具有椭圆空气孔微结构光纤相比,提出的光纤结构更易于制作.研究结果为开辟2μm波段光器件的研究做出了有益的探索.     

Thermal stability of copolymer derived from l-lactic acid and poly(tetramethylene) glycol through direct polycondensation

The thermogravimetric analysis (TG) of triblock copolymers (PLAG) based on poly(l-lactic acid) (PLLA) and poly(tetramethylene) glycol (PTMEG) segments with different PTMEG content and catalyst concentration was conducted. The thermal degradation behaviors of copolymers were determined by thermogravimetric analysis and the results are also confirmed by hydrogen nuclear magnetic resonance spectrometry (¹H NMR). The thermal stability of PLA-based copolymer is improved with decreasing use level of Sn catalyst and short-chain molecules with hydroxyl and carboxyl end group also have a significant effect on the thermal degradation of chain-extended products of copolymer (PLAE). PLAE-10 with 0.5 wt% catalyst shows two main decomposition kinetic mechanisms. On the other hand, PLAE-10 with 0.05 wt% catalyst mainly undergoes Sn-catalyzed selective depolymerisation. Moreover, the PTMEG segments in PLAEs seem to increase the mobility of the Sn salt moiety in PLAEs and the activation energy (E _a) decreases with increasing the PTMEG content in PLAEs.     

Investigation on the Percutaneous Enhancing Permeation Mechanism of Azone for Ketoprofen Based on the Intermolecular Hydrogen-bonding Interaction

The permeation enhancing activity of Azone for ketoprofen through excised cavia skins was investigated using Franz diffusion cell. The possible hydrogen-bonded complexes formed between ketoprofen and the model molecule of Azone as azacyclopentane-2-one were fully optimized at the B3LYP/6-311++G** level. The intermolecular hydrogen-bonding interactions were calculated using the B3LYP/6-311++G**, B3LYP/6-311++G(2df, 2p), MP2(full)/6-311++G** and MP2(full)/6-311++G(2df, 2p) methods, respectively. The results show that the steady-state permeation rate of ketoprofen through excised cavia skins enhances over 9 times in the solvent with 2% Azone as compared with the solvent without Azone. The stable O–H···O=C and N–H···O=C hydrogen-bonded complexes could exist between azacyclopentane and ketoprofen. The hydrogen-bonding interaction energy follows the order of(a) (b) (c) (d) (g)(e) (h) (f). The formation of the complexes leads to the change of the conformation and molecular polarity of ketoprofen, and thus causes a better percutaneous permeation for the drug. The analyses of AIM(atom in molecule) and shift of electron density were used to further reveal the nature of the enhancing permeation activity of Azone for ketoprofen. The investigations of the temperature and solvent effects confirm that ketoprofen might enter into the skin by means of the Azone complex.