High spatial resolution distributed strain sensor based on linear chirped fiber Bragg grating and fiber loop ringdown spectroscopy

A simple sensor system for high spatial resolution distributed strain field measurement is proposed and demonstrated experimentally. The fiber loop ringdown technique combined with a linear chirped fiber Bragg grating is used to realize the high spatial resolution. A proof-of-concept distributed strain sensor with 2?mm spatial resolution is realized. The sensor network is also explored and researched experimentally. The proposed technique suggests a broad range of applications for real-time distributed physical parameter sensing, such as strain or temperature.     

Efficient green-light generation by proton-exchanged periodically poled MgO:LiNbO3 ridge waveguide

Efficient cw 532?nm green-light generation is demonstrated using a periodically poled MgO:LiNbO3 ridge waveguide prepared by a process that combines annealed proton exchange and precise dicing. Performance of waveguides with different widths has been investigated. The 6-μm-wide, 1.6-cm-long uncoated ridge waveguide has achieved a green output power of 127?mW under a coupled fundamental light power of 250?mW. The highest conversion efficiency achieved is 53%.     

螺旋线型微秒级高压长脉冲产生器数值模拟

 探索了采用CST软件和PSpice软件进行加速器场分布数值模拟的方法,利用该方法可方便地获取设备内部动态场分布图及动态电压变化规律。针对螺旋线型μs级高压长脉冲产生器系统建立了数值模拟模型,给出了详细的模拟步骤及结果。分析表明,利用场分布模拟方法获取的电压变化规律与电路模拟方法获取的结果是一致的。基于CST模拟方法,可以给出螺旋线及主开关等电气结构的瞬态电场分布,场强增强点主要出现在螺旋带的外沿及金属电极连接处,在介质支撑内部也有较高的场强分布。     

Destabilization of artificial biomembrane induced by the penetration of tryptophan

The effect of tryptophan on the membrane stability was studied by using three artificial biological membranes including liposome, Langmuir monolayer and solid supported bilayer lipid membrane (s-BLM) as models. All the results indicate that the penetration of tryptophan can destabilize different artificial biological membranes. The diameter of liposome and the leakage of calcein from liposome increased with the increase of tryptophan concentration because the penetration of tryptophan was beneficial for dehydrating the polar head groups of lipids and the formation of fusion intermediates. π-A isotherms of lecithin on the subphase of tryptophan solution further confirm that tryptophan can penetrate into lipid monolayer and reduce the stability of lipid monolayer. When the concentration of tryptophan increased from 0 to 2 × 10⁻³ mol L⁻¹, the limiting molecular area of lecithin increased from 110.5 to 138.5 Å², but the collapse pressure of the monolayer decreased from 47.6 to 42.3 mN m⁻¹, indicating the destabilization of lipid monolayer caused by the penetration of tryptophan. The resistance spectra of s-BLM demonstrate that the existence of tryptophan leads to the formation of some defects in s-BLM and the destabilization of s-BLM. The values of electron-transfer resistance and double layer capacitance respectively decreased from 5.765 × 10⁶ Ω and 3.573 × 10⁻⁸ F to 1.391 × 10⁶ Ω and 3.340 × 10⁻⁸ F when the concentration of tryptophan increased from 0 to 2 × 10⁻³ mol L⁻¹. Correspondingly, the breakdown voltage of s-BLM decreased from 2.51 to 1.72 V.     

Modification of surface properties of polyamide 6 films with atmospheric pressure plasma

To investigate the effect of the different plasma gases treatment on the surface modification of atmospheric pressure plasma, polyamide 6 films were treated using pure helium (He), He/O₂ and He/CF₄, respectively. Atomic force microscopy (AFM) showed rougher surface, while X-ray photoelectron spectroscopy (XPS) revealed increased oxygen and fluorine contents after the plasma treatments. The plasma treated samples had lower water contact angles and higher T-peel strength than that of the control. The addition of small amount of O₂ or CF₄ to He plasma increases the effectiveness of the plasma treatment in polymer surface modification in terms of surface roughness, surface hydrophilic groups, etching rate, water contact angle and bonding strength.     

Structural, elastic and electronic properties of a new ternary-layered Ti2SiN

The structural, elastic and electronic properties of Ti₂SiN were studied by first-principle calculations. The calculated bond lengths of Ti-Si and Ti-C are 2.65 and 2.09 Å, respectively. The results show Ti₂SiN is mechanically stable, and its bulk modulus B, shear modulus G, Young's modulus E, Poisson's ratio μ and anisotropy factor A are determined to be 182 GPa, 118 GPa, 291 GPa, 0.233 and 1.57, respectively. The calculated electronic structure indicates that Ti₂SiN is anisotropic and conductive.     

针板型触发电晕稳定开关的特性

 为了验证在空气状态下电晕稳定开关的重复频率特性,对自行研制的盘式触发三电极电晕稳定开关的工作特性进行了实验研究,并分析了实验结果。结果表明,在空气状态下,开关具有良好的触发特性,开关抖动和导通时延最小可以分别控制在4, 36 ns;同时,还可以通过减小触发间隙,进一步减小开关的导通时延和增加开关的稳定性。     

AgTCNQ衍生物旋涂膜绿光可擦重写光存储性质研究

报道了新型电子转移复合物AgTCNQ脂类衍生物：银-(2,5-二丙酸甲酯-7,7,8,8-四氰基对苯醌二甲烷)的旋涂薄膜的光谱特征、薄膜的静态绿光可擦重写光存储性能,并研究了薄膜的可擦重写机理。结果表明该薄膜在388nm和675nm处有两个源于复合物中阴离子自由基TCNQ(C2H4COOCH3)2^-中的电子跃迁的特征吸收峰;AgTCNQ酯类衍生物旋涂膜具有良好的绿光光存储性能,该薄膜在写入功率为9mW,写入脉冲为80ns,擦除功率为4mW,擦除脉冲为500ns时反射率衬比度大于15％,循环次数可达100次以上,并且没有出现任何疲劳现象。机理研究表明,AgTCNQ酯类衍生物与AgTCNQ有着相同的可逆光致变色机理,即在激光作用下因复合物中可逆电子转移引起薄膜光学性质的可逆变化,从而实现可擦重写光信息存储。