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重离子辐射诱导大肠杆菌BL21的旁观者效应
No full text<正>电离辐射诱导的旁观者效应是指,与受辐射细胞相邻的或共用培养基的旁观者细胞出现类似直接受辐射细胞出现的反应[1]。尽管对哺乳动物细胞中的旁观者效应已经有
甜高粱重离子诱变改良研究进展
No full text<正>甜高粱(Sorghum bicolor(L.)Moench)属C4植物,具有很高的光合效率,是世界上生物量最高的作物,故有"高能作物"之称。另外,甜高粱具有抗旱、耐涝、耐贫瘠
~(12)C~(6+)离子预辐射对小鼠胸腺脾脏细胞周期进程的影响
No full text以0,0.05,0.1,0.25,0.5Gy12C6+离子全身预辐照昆明小鼠,间隔4h后再对小鼠进行4Gy全身辐射。辐照后12h用流式细胞仪检测小鼠胸腺脾脏细胞在各细胞周期时相的百分率,同时用单细胞电泳检测受辐射小鼠胸腺脾脏细胞DNA损伤程度。结果显示,相对于大剂量预照射组,各低剂量预照射组胸腺细胞S期细胞百分率显著减少;脾脏细胞G0/G1期细胞百分率明显减少;同时胸腺脾脏细胞的拖尾率及拖尾长度明显减少,以0.1Gy预辐照效果最为明显。这些结果表明,低剂量预辐射处理可以减弱胸腺细胞的S期阻滞及脾脏细胞的G1期阻滞,并明显减轻胸腺脾脏细胞的DNA损伤程度
Optical properties revealing annealing behavior of high-temperature He-implantation induced defects in silicon carbide
No full text对氦(He)离子高温(600K)注入6H-SiC中的辐照缺陷,在阶梯温度退火后演化行为的拉曼光谱和室温光致发光谱的特征进行了分析.这两种方法的实验结果表明,离子注入所产生晶格损伤的程度与注入剂量有关;高温退火导致损伤的恢复,不同注入剂量造成的晶格损伤需要不同的退火温度才可恢复.在阶梯温度退火下呈现出了点缺陷的复合、氦-空位团的产生、氦泡的形核、长大等特性.研究表明:高温(600K)注入在一定剂量范围内是避免注入层非晶化的一个重要方法,为后续利用氦离子注入空腔掩埋层吸杂或者制备低成本、低缺陷密度的绝缘层上碳化硅(SiCOI)材料提供了可能.6H-SiC single crystal specimens were implanted at 600 K with 100 KeV He ions to three successively increasing fluences and subsequently annealed at different temperatures ranging from 600 degrees C to 1200 degrees C in vacuum. After the annealing, the samples were investigated by using Raman scattering spectroscopy and photoluminescence spectrometry, respectively. Both of the two methods showed that the damage induced by helium-ion-implantation in the lattice is closely related to the dose. The thermal annealing brings about recovery of the damage,and different levels of damage require different annealing temperature to recover efficiently. It is indicated that different annealing stages involve different mechanisms, corresponding to recombination of point defects, formation of He-vacancy complexes, and nucleation and coarsening of bubbles, respectively. The experimental results indicate that high temperature implantation is an effective way to avoid amorphization of the implanted layer due to damage accumulation. Helium implantation can be used to introduce buried nanoscale cavities as the nucleation site for the buried oxide in a well defined region proposed for an altemative and more economical method of manufacturing SiC-on-Insulator (SiCOI)
离子辐照对生防菌BJ1的诱变研究及菌种鉴定
No full text为了提高生防菌BJ1的抑菌能力,优化辐照诱变的物理参数,获得生防效果更好的高效菌种,利用12C6+对生防菌BJ1进行不同剂量离子辐照处理。结果表明,采用100Gy剂量辐照的生防菌BJ1的存活率最高,并且在0～100Gy之间,存活率先降后升,其存活曲线呈"鞍型";从诱变效果看,经400Gy辐照诱变获得的生防菌BJ1的抑菌效果有明显提高;综合存活和抑菌效果考虑,离子辐照诱变生防菌BJ1的最适剂量为200～400Gy。通过16SrDNA序列分析,将辐照诱变获得的BJ1菌株定为枯草芽孢杆菌
一种低活化铁素体/马氏体钢的高能重离子辐照效应研究
No full text低活化的铁素体/马氏体钢是先进核能装置(如聚变堆)的重要候选结构材料。在聚变堆实际工作环境下,由于高温和高氦产生率引起的材料失效是这类材料面临的一个重要问题。本项研究以兰州重离子加速器(HIRFL)提供的中能惰性气体离子束(20Ne,122 MeV)作为模拟辐照条件,借助透射电子显微镜,研究了一种低活化的9Cr铁素体/马氏体钢(T92B)组织结构的变化和辐照肿胀。实验结果表明,高温下当材料中晶格原子的撞出损伤和惰性气体原子沉积浓度超过一定限值时,材料内部形成高浓度的空洞,并且空洞肿胀率显著依赖于辐照温度和剂量;在马氏体板条界面及其它晶界处空洞趋于优先形成,并且在晶界交汇处呈加速生长。基于氦泡的形核生长与空洞肿胀的经典模型探讨了在不同辐照条件(He离子、Ne离子、Fe/He离子双束、快中子、Ni离子)下铁素体/马氏体钢中肿胀率数据的关联
改进的QMD模型研究不同入射道条件对同位旋分馏强度的影响
No full text通过在同位旋相关量子分子动力学模型(IQMD)中引入同位旋依赖的动量相关作用和同位旋相关的Skyrme势,得到了改进的同位旋依赖的量子分子动力学模型,并用此模型分析和讨论了中能重离子碰撞中的同位旋分馏强度随入射道条件的演化.结果表明在中能重离子碰撞中各种入射道条件下同位旋依赖的动量相关作用和Skyrme势有着明显的同位旋效应,它们减弱了同位旋分馏的过程
Dependence of the cross sections for Ir isotopes on the values of Qgg in the heavy ion collision
No full text197Au were irradiated with 47 MeV/u 12C ions. Iridium was produced via the multinucleon transfer reactions in bombardments of 197Au with 12C. and was separated radiochemically from Au and the mixture of the reaction products. The γ radioactivities of Ir isotopes were measured by using a HPGe detector. The production cross sections of Ir isotopes were determined from activities of Ir isotopes at the end of bombardment and the other relative data. It has been found that the cross sections for neutron-rich iso..
Extraction behavior of short-lived isotopes of Mo/W using α-benzoinoxime: A model system for the study of seaborgium
No full textSimulation of Gas Chromatographic Processes by Monte Carlo Method
No full textBased on Monte Carlo method the microscopic gas-phase adsorption chromatographic behaviors of volatile chemical compounds were simulated,and the migration process of those compounds followed by the carrier gases along the chromatographic surface and the process of adsorption-desorption were also described.The programs have been compiled to simulate the processes of thermochromatography and isothermal chromatography with different experimental conditions and properties.The calculated results agree well with ...中文摘要：用蒙特卡罗方法模拟了易挥发化合物的气相色谱微观动力学行为,描述了化合物随气流在固体色谱柱表面的迁移以及吸附-解吸等过程。按气相色谱微观动力学模型编译的计算机程序模拟了超重元素化合物在等温色谱及热色谱的动力学过程,并根据不同实验条件进行了大量计算。计算结果与实验数据较为吻合。讨论了超重元素的半衰期、吸附态的周期、载气流量以及化合物的质量密度等对实验结果的影响及该理论模型的优点和待改进的地方