12C6+重离子辐照大葱的生物学效应

用30Gy、90Gy和180Gy 12C6 重离子辐照处理大葱干种子,研究了它对大葱的生物学效应.经过不同剂量12C6 重离子照射过的大葱,幼苗发芽率、株高等表型随着辐照剂量的增大,呈现明显的"抛物线"趋势.适量的12C6 重离子照射(30Gy)能提高大葱发芽率和抗旱、抗倒伏能力,促进生长发育.重离子辐照能有效地诱导大葱根尖细胞微核和染色体畸变形成,180Gy处理的大葱微核率和染色体畸变率最高达到9.09%和10.03%.本实验为大葱的重离子辐照育种打下基础.     

离子束辐照对玉米诱变效应的初步研究

利用兰州重离子加速器提供的12C6+和36Ar18+离子束对玉米自交系郑58、鲁9801、金象4C-1、CSR24001、308和478进行辐照诱变育种试验,探讨了重离子辐照对玉米的诱变效应。结果显示,重离子辐照后种子出苗率和成苗率根据材料不同表现不一,浸泡后种子对辐照敏感性增加。辐照后M1代叶型变异较大;M2代植株经济性状发生变异较多,产生了许多有益的突变性状;M3代部分突变性状能够稳定遗传。由此可见,重离子束辐照育种有利于品种改良和种质创新,是玉米遗传改良的一种有效手段。     

重离子辐照微生物效应及诱变育种进展

重离子束作为一种高效的、典型的诱变辐射源广泛用于生物育种。不同质量数、电荷数和不同能量的重离子束作用于生物细胞有特殊的过程和作用,其先后经历物理、化学和生物学三个阶段,最终引发终点生物学效应,如辐射低剂量超敏感现象,活性氧代谢变化等。本文重点探讨重离子束辐照微生物体后出现的主要终点生物效应,以及近年来重离子辐照微生物诱变育种在工农业等方面取得的成果。     

12C6+重离子辐照油菜诱变效应研究

用30Gy、90Gy和180Gy12C6 重离子辐照油菜干种子,研究其对油菜M1代的诱变效应.结果表明不同剂量12C6 重离子辐照使油菜的出苗率、株高和开花率有不同程度的提高,并使开花期提早;30Gy辐照使单株角果数和单株产量有了一定程度的提高;三种辐照剂量都造成了花粉生活力、千粒重和含油量的降低.RAPD扩增结果表明,42个随机引物中有13个引物扩增出差异条带,30Gy、90Gy和180Gy引起的RAPD变异率分别为22.1%、23.7%和36.2%.研究表明,12C6 重离子辐射能有效地引起油菜DNA序列发生改变,从而诱导基因变异,为油菜育种提供丰富的种质材料.     

55MeV/u 40Ar17+离子在生物等效材料中产生的核碎片

利用HIRFL（兰州重离子研究装置）产生的55MeV/u的^40Ar^17 离子束，在辐照生物学实验终端，测量了其经过1.5mm厚有机玻璃后三个不同角度的碎片分布情况，探索了应用CsI(Tl) 快塑料闪烁探测器组成的Phoswich探测器研究重离子在生物材料中产生的核碎片角分布测量的可行性，结果表明这种实验方法是可行的，实验结果令人鼓舞，本工作为进一步的实验积累了可靠的经验。     

液态水中重离子径迹结构及能量沉积分布的研究

介绍了重离子径迹结构及能量沉积分布理论研究的进展情况，给出了重离子Ｍｏｎｔｅ Ｃａｒｌｏ计算模型以及电子径迹中的能量沉积几率分布和重离子径向剂量分布等计算结果。     

液态水中重离子径述结构及能量沉积分布的研究

介绍了重离子径述结构及能量沉积分布理论研究的进展情况，给出了重离子ＭｏｎｔｅＣａｒｌｏ计算模型以及电子径迹中的能量沉积几率分布和重离子径向剂量分布等计算结果。     

HI—13串列加速器重离子扫描辐照装置

介绍了ＨＩ－１３串列加速器重离子扫描辐照装置的研制结果。其技术和工艺有如下特点：（１）能对１００—２００ＭｅＶ能区的重离子进行扫描；（２）采用二维（ｘ，ｙ）扫描方式；（３）小巧紧凑的扫描磁铁；（４）特制的磁极内陶瓷束流管道；（５）使用了三角波扫描磁场电源；（６）紧凑精密的扫描靶室和辐照传动靶室。该装置可满足核孔膜高级滤材、大功率快速电子器件改性以及生物样品等重离子均匀辐照的需要。     

新型的核乳胶探测技术

介绍了三种可以准确，快速，半自动（全自动）测量的核乳实验新技术，这些技术特别适合于测量超高能重离子碰撞中心事例中带电粒子的发射角。     

重离子辐照对红酵母的诱变作用

应用重离子加速器的50MeV／u^12C^6 重离子对胡萝卜素生产菌-红酵母(Rhodotorula RY Strain)进行辐照处理,经酵母发酵实验,发现50MeV／u^12C^6 重离子对胡萝卜素生产菌-红酵母具有诱变作用。初步筛选到了胡萝卜素产量有变化的辐照变异菌株,并对这些辐照变异菌株进行了RFLP(限制性片段长度多态性)和RAPD(随机扩增DNA多态性)分析,这些工作为工业上利用重离子对胡萝卜素生产菌进行诱变育种展现了新的前景。     

MeV离子辐照拟南芥的萌发规律研究

利用不同能量的F离子和H离子分别辐照拟南芥干种子,通过种子发芽率实验研究了低能离子生物效应与离子种类、离子能量和辐照注量之间的关系。实验结果表明,H离子的辐照效率高于F离子;F离子辐照的种子发芽率曲线,随F离子注量的增加,均呈现先下降后升高再下降的马鞍曲线形状,达到马鞍峰值需要的注量随离子能量的增加而减少。文中对上述现象的可能机理进行了讨论。     

中能氩离子束辐照麦胚自由基的ESR研究

用ＥＳＲ波谱技术，研究了室温下中能氩离子辐照小麦种子胚部产生的自由基，观察了自由基的稳定性，实验结果表明，种子中自由基浓度随种子含水量线性增加，自由基浓度随辐照剂量增加，然后趋于饱和，讨论了自由基与种子损伤的关系。根据实验数据和 自由基扩散理论估算了自由基在麦胚中扩散距离。     

离子注入对菲胁迫下的苜蓿萌发的影响

为研究离子注入对多环芳烃(Polycyclic aromatic hydrocarbons,PAHs)修复植物的诱变效应,利用离子注入苜蓿草种,探讨了离子注入后苜蓿在不同含菲质量分数环境中的萌发率和芽根长度分布.结果发现,苜蓿萌发率随注入剂量的增大,呈“鞍形”曲线特征;以植物主根长度为诱变筛选条件,发现5×1015 c...     

Laser beam irradiation of silver doped silicate glasses

Planar light waveguides prepared by Ag-Na ion exchange in molten salt bath are irradiated with Nd:YAG laser beams at different wavelengths in the IR and VIS regions, and for different energy density and repetition rate values. The samples are characterized by optical spectroscopy to determine the role of irradiation parameters in the Ag clustering process, including aggregation phenomena and possible cluster photofragmentation. The appearance of the characteristic plasmon resonance feature in the optical absorption spectra marks the formation of Ag clusters, as observed by electronic microscopy as well, and permits to follow the evolution of the whole clustering process upon increasing of the deposited energy density. Photoluminescence spectroscopy has given specific information concerning the presence of Ag multimeric aggregates, considered as embryonic structures for the growing nanoclusters. The systematic investigation presented in this work is expected to clarify some aspects of the interaction between the laser beam and the doped glass matrix, and to help establishing suitable methodologies for the controlled preparation of nanocomposite glasses.     

中能氮离子束辐照小麦种子产生自由基的研究

用ＥＳＲ波谱术研究了室温下中能氮离子辐照小麦种子产生的自由基，发现氮离子贯穿和注入小麦种子产生的自由基浓度随剂量的变化具有不同的特征。对氮离子贯穿小麦种子产生的自由基浓度随剂量率的变化规律也进行了研究。     

Ion irradiation effects on the optical properties of tungsten oxide films

The optical changes in amorphous WO₃ film prepared by reactive RF sputtering and irradiated by 200-800 keV oxygen ions were measured to study the relationship between coloration and energy deposition. The color centers were effectively created by ion irradiation with contributions from nuclear collisions and electronic energy loss. The increase in the absorption coefficient was reasonably explained by a first order reaction, whose production rate depended roughly on the total deposited energy. During heat treatment in air atmosphere, transmittance recovery started at 400 K and completed at 550 K. No significant difference was found among films irradiated by different incident energies; therefore indicating that the ion-induced damage structure is not strongly influenced by the type of energy loss.     

Swift heavy ion irradiation induced nanoparticle formation in CeO2 thin films

Nanoparticle formation in the, rf-sputtering grown, polycrystalline CeO₂ thin films is achieved by the swift heavy ion (SHI) irradiation. Crystal structure and phases present in the as-grown and irradiated thin films are investigated by the X-ray diffraction (XRD) measurements. Irradiation induced formation of spherically shaped nanostructures, on the film surface, is confirmed by the atomic force microscopy (AFM). The Raman spectra of the irradiated samples show increased line-width and peak position shifting in the Raman active mode (F_2g) of CeO₂, indicative of the nanocrystallization in the irradiated CeO₂ thin films. Formation of nanostructures in the irradiated samples is also briefly discussed in the light of ion energy and energy loss mechanisms.     

An important mechanism of crop breeding with ultralow energy ion implantation

The characteristic X-rays excited in carbon compounds of seeds by ultralow energy (110 keV) ions implanted in wheat seeds were simulated with carbon-light of synchrotron-radiation. After the seeds were irradiated with the C-light, the through-germination survival fraction of the seeds and the micronucleus frequency in their root-tip cells could be measured. The data verify that the characteristic X-rays excited by the ultralow energy ions implanted in the seeds provide an important mechanism of crop breeding.     

Impedance studies on high energy Li irradiated PZT thin films

The ferroelectric Pb(Zr_0.48Ti_0.52)O₃ (PZT) thin films prepared by the pulsed laser deposition technique were studied for their response to high energy lithium ion irradiation through impedance spectroscopy. The Debye peaks, observed in the impedance and modulus plots of irradiated films, shifts towards higher frequencies compared to those of unirradiated films. This is equivalent to the trend observed with increase in temperature in the unirradiated films due to the dielectric relaxation. The irradiated films showed a decrease in the grain resistance compared to the unirradiated films. The activation energy of dielectric relaxation increases from 1.25 eV of unirradiated film to 1.62 eV of irradiated film. The observed modifications in the irradiated film were ascribed to the modifications in the grain structure due to the high value of electronic energy loss.