核科学百年讲座第五讲辐射化学与辐射加工

介绍辐射化学和辐射加工的发展与应用，以及基本原理，侧重介绍辐射加工在高分子辐射交联改性、食品的辐照处理和医疗用品消毒等方面的应用．     

Function S-rough Sets and Their Law Characteristic

Function S-rough sets(Function Singular rough sets) are defined by R-function equivalence class which has dynamic characteristic, and a function is s law, function S-rough sets have law characteristic. Function S-rough sets has these forms: function one direction S-rough sets, function two direction S-rough sets and dual of function one direction S-rough sets. This paper presents the law characteristic of function one direction S-rough sets and puts forward the theorems of law-chain-attribute and law-belt. Function S-rough sets is s new research direction of the rough sets theory.     

A Novel Method for Measuring the Photo－Induced Birefringence of Photosensitive Fibres Based on a Fibre Loop ＊

We report a novel method for measuring photo-induced birefringence of photosensitive fibres based on a fibre loop.The method is simple and is only slightly affected by the surroundings. The experimental results show that thephoto-inducing normalized birefringence of the photosensitive fibre is multi-decaying-exponentially proportionalto the exposure and it can attain 10^-5.     

A Dual-Wavelength Cladding-Pumped Er^3＋/Yb^3＋ Codoped Fibre Laser System with More Than 2 W Output and Tunable Wavelength Spacing

A dual-wavelength laser system with wideband tunable wavelength spacing and more than 2 W output power is proposed and demonstrated. The operation principle of the laser system is based on the saturation gain characteristic of a cladding-pumped Era＋ /yba＋ co-doped fibre amplifier combining with a wideband tunable fibre laser with fiat power spectrum. The tuning range of the wavelength spacing is continuous within a 35 nm spectral range, and the power difference between both lasing wavelengths can be easily adjusted and controlled by a variable optical attenuator. The total output power can approximately keep unchangeable when the wavelength spacing and the power difference between both lasing wavelengths are continuously tuned and changed. The maximum total output power of the laser system is about 2.22 W.     

波长间隔可调的可开关双波长掺铒光纤激光器

对两种波长间隔可调的可开关双波长掺铒光纤激光器结构进行了实验研究。一种结构应用保偏光纤中布拉格光栅作为波长选择器件，另一种结构则利用侧向压力下的常规单模光纤光栅作为波长选择器件。两种结构均利用了光纤光栅的双折射特性。在室温下，通过调整偏振控制器的状态可使两激光器工作在稳定的双波长状态或在两单波长之间转换。通过改变加在光纤光栅上侧向应力的大小和方向，可有效控制双波长激射的波长间隔。     

柚子型微结构光纤Bragg光栅温度和应变传感特性研究

通过对柚子型微结构光纤Bragg光栅的多个反射峰的温度和应变传感特性进行的理论和实验 研究，得出柚子型微结构光纤Bragg光栅的反射波长与温度呈二次关系，且理论和实验二者 吻合较好; 同时发现每个反射峰的温度灵敏度不同.理论分析柚子型微结构光纤Bragg光栅的 反射波长与应变呈线性关系，实验得到了该种Bragg光栅的反射波长与应变的线性关系，实 验结果与理论分析相吻合.由于微结构光纤光栅反射谱中多个峰对温度和应变等物理量敏感 度不一致，这种Bragg光栅更适合应用到多参量传感领域. 关键词： 微结构光纤 光纤Bragg光栅 温度传感 应变传感     

小型化长脉冲二极管设计与实验

在长脉冲高功率微波源研究中关键的部件是二极管，由于阴极爆炸发射产生的阴极等离子体的热扩散，为防止二极管短路，长脉冲二极管通常比一般二极管阴阳极间距大，尺寸也相应较大。原有的长脉冲加速器使用的二极管如图1所示，这也是美国BANSHEE加速器采用的二极管结构。使用的二极管是为满足L波段高功率微波器件的需要，产生电子束电压500kV，电流3kA，脉宽1．5μs，束截面内外径为φ5．7，φ7．3cm。现在为了满足开展S波段相对论速调管研究需要，设计了新的小型化二极管，产生电子束环内外直径约φ4.3，φ3．7cm。     

南蛇藤中倍半萜生物碱的二维NMR研究

用DEPT和二维NMR技术包括:¹H-¹H COSY,¹H-¹³C COSY,NOESY,特别是¹H-¹³C COLOC对两个多酯基取代的倍半萜生物碱的化学及立体结构进行了研究,并对其¹H和¹³C NMR谱峰进行了归属。     

非本征型法布里-珀罗干涉仪光纤布拉格光栅应变温度传感器及其应用

介绍了光纤布拉格光栅非本征型法布里珀罗干涉仪集成复用传感器的结构、应变和温度同时监测的原理 ;观察到光纤布拉格光栅反射谱和非本征型法布里珀罗干涉仪干涉谱间的串扰 ,用 3dB带宽平均波长法减小了该串扰 ,提高了测量精度 ;将该传感器应用于三维编织复合材料的应变及温度同时监测。实验结果表明温度精度为± 1℃ ,应变精度为± 2 0 μ ,可满足实际应用的要求     

内毒素肺损伤对多形核白细胞化学发光的影响

本文研究了绵羊内毒素肺损伤对全血多形核白细胞(PMN)化学发光的影响;比较了正常混合血浆正常自体血浆和自体致伤血浆调理酵母多糖对发光的影响;观察了致伤后的血浆和肺淋巴液的发光促进活性.结果表明,内毒素致伤后,PMN的化学发光峰时无显著变化,而峰值于4h前呈直线上升,4h达高峰,而后逐渐减弱,但至24h仍明显大于伤前值.三种不同血浆调理酵母多糖对PMN发光无明显影响.致伤后期(2h后)的血浆和肺淋巴液无发光促进活性.这些结果提示,一次性微量的大肠杆菌内毒素对PMN的发光具有强烈和持久的促进作用,而对血浆的调理能力无明显影响.