电子辐照PVA/CMC共混水凝胶的成胶研究

本试验利用电子辐照PVA/CMC共混水凝胶,通过外观透明度、凝胶分数、溶胀度和红外光谱分析,研究了样品中结构的变化与外观透明度、凝胶分数和溶胀度的关系,以及辐照剂量对样品中结构和性能的影响.结果表明,不同比例的PVA与相同比例的CMC组成的共混水凝胶,经电子辐照后呈现不同的宏观特性.辐照样品萃取后得到的凝胶比萃取前的混合凝胶拥有更强的吸水性,表明辐照PVA/CMC共混凝胶形成了网状结构凝胶.几种竞争反应导致不同辐照剂量下混合凝胶中凝胶含量随PVA含量的变化变得复杂.辐照后样品的红外光谱分析显示,辐照使凝胶中部分仲醇中C上链接的H原子被取代而转变为叔醇,从而产生交联.     

离子辐照引起Eu掺杂氧化镁的发光特性

利用320 kV高压综合实验平台,通过6 MeV Xe离子辐照Eu掺杂氧化镁(MgO)单晶样品对其光致发光现象进行了研究。Xe离子辐照后,样品380~550 nm的发光带出现先减弱后增强的现象,400~450 nm处出现了平坦的较宽的蓝色发光带,经拉曼光谱和红外光谱的综合分析可知离子辐照能够使掺杂的Eu很好的进入晶体内部形成稳定的缺陷类型,产生更好的发光效果。     

Modification of Optical Band-Gap of Si Films After Ion Irradiation

Amorphous silicon (a-Si),nanocrystalline silicon (nc-Si) and hydrogenated nanocrys-talline silicon (nc-Si:H) films were fabricated by using chemical vapor deposition (CVD) system.The a-Si and nc-Si thin films were irradiated with 94 MeV Xe-ions at fluences of 1.0×10 11 ions/cm-2,1.0×10 12 ions/cm-2 and 1.0×10 13 ions/cm-2 at room temperature (RT).The nc-Si:H films were irradiated with 9 MeV Xe-ions at 1.0×10 12 Xe/cm-2,1.0×10 13 Xe/cm-2 and 1.0×10 14 Xe/cm-2 at RT.For comparison,mono-crystalline silicon (c-Si) samples were also irradiated at RT with 94 MeV Xe-ions.All samples were analyzed by using an UV/VIS/NIR spectrometer and an X-ray powder diffractometer.Variations of the optical band-gap (E g) and grain size (D) versus the irradiation fluence were investigated systematically.The obtained results showed that the optical band-gaps and grain size of the thin films changed dramatically whereas no observable change was found in c-Si samples after Xe-ion irradiation.Possible mechanism underlying the modification of silicon thin films was briefly discussed.     

Xe23+离子辐照Al2O3的光谱特性

本工作研究460 keV、3 MeV和308 MeV Xe23 辐照Al2O3单晶样品的光致发光特性.从经过460 keV Xe23 辐照后样品的光致发光测试结果可看到,波长为380、413和450 nm的发光峰明显增强,在390和564 nm处出现了新的发光峰.从3 MeV的Xe23 辐照后样品谱的变化可看到,在较低剂量条件下,516 nm(2.4 eV)和564 nm(2.2 eV)处的发光峰随辐照剂量增加而增强,且当剂量增到1×1016 cm-2时,564 nm处的发光峰消失,只有516 nm(2.4 eV)处的发光峰较强.从308 MeV Xe23 辐照后样品的光致发光谱中可看到,357 nm(3.47 eV)和516 nm(2.4 eV)处的发光峰随着剂量增加明显增强.辐照后样品的FTIR谱显示:波数在460～510 cm-1和630 cm-1附近的吸收是Al2O3振动模式,经离子辐照后,吸收带展宽;1 000～1 300 cm-1间为Al-O-Al桥氧键的伸缩振动模式,高能辐照后的吸收带向低波数方向移动.