重离子束辐照选育高产植物乳酸菌

采用重离子束~(12)C~(6+)对乳酸菌出发菌株JTL进行辐照选育。确定吸收剂量300 Gy时最优,在该吸收剂量下,出发菌种的正突变率和致死率均达到最高,分别为34.4%、80%。通过酸斑法初筛和发酵复筛法,选育出高产酸的3株突变菌株(JTL2、JTL3、JTL5),其发酵液中乳酸含量比出发菌株JTL提高了41.29%~49.64%。同时,经过传代实验证实,3株菌株具有良好的遗传稳定性。研究表明,利用重离子束~(12)C~(6+)辐照处理乳酸菌可以得到高产酸的突变菌株,诱变效果显著。     

碳离子束辐照对甜高粱主要性状的影响

利用兰州重离子加速器国家实验室(HIANLL)提供的100 MeV/u碳离子束对甜高粱品种BJ0601和BJ0602进行了不同剂量的辐照处理,并用SPSS13.0软件分析了碳离子束辐照剂量和甜高粱主要性状节间数、株高、茎粗、含糖量及单秆重的相关性,试验结果表明:不同的辐照剂量对甜高粱节间数、株高、茎粗、含糖量及单秆重产生了明显的影响,表现出不同程度的相关性.另外,早熟突变株BJ0601-1 M2代各节的平均含糖量高于BJ0601,说明碳离子束辐照可能引起甜高梁含糖量的提高.     

羟基红花黄色素A对碳离子束辐照致放射性脑损伤的保护作用

探究传统活血化瘀中药红花活性成分羟基红花黄色素A(HSYA)对12C6+重离子束诱发放射性脑损伤的保护作用。昆明种小鼠60只,随机分为正常组、辐照对照组、HSYA低(5 mg/kg)、中(10 mg/kg)、高(20 mg/kg)剂量干预组。给药组于辐照前3 d起每日腹腔注射相应剂量药物,末次给药后1 h,以4.0 Gy12C6+辐照小鼠头部。辐照1个月后,通过Morris水迷宫实验检验小鼠认知功能,以伊文思蓝(EB)作为指示剂测定小鼠血脑屏障通透性,并分别用亚硝酸盐形成法和硫代巴比妥酸(TBA)法测定脑组织中超氧化物歧化酶(SOD)活性及脂质过氧化产物丙二醛(MDA)的含量。结果显示,经12C6+辐照后,单纯照射组小鼠表现出明显的认知功能障碍(P<0.01),小鼠血脑屏障通透性明显升高,脑组织SOD活性明显降低,MDA含量明显增加,羟基红花黄色素A可剂量依赖性地改善小鼠认知功能障碍,保护血脑屏障,上调SOD活性,并降低MDA含量,表明羟基红花黄色素A对12C6+重离子束诱发放射性脑损伤有保护作用。     

碳离子束辐照大豆当代诱变效应及褐皮突变体的初步研究

利用不同剂量碳离子束辐照大豆"合丰55"干种子,通过对表型、株高、分枝数及产量相关性状的考察以及DNA指纹图谱分析探索离子束辐照大豆的当代诱变效应。结果表明离子束诱变大豆M1代田间出现多种变异表型,辐照处理对M1代株高和分枝数有抑制作用,单株荚数、单株粒数、单株粒重及百粒重随着辐照剂量的增加呈现先降低后升高再降低的趋势,但这些变异与对照相比并未达到显著水平。大豆种子经辐照后M1代筛选到1株褐皮突变体,种皮颜色由黄色变为褐色,而且这种变异在M2代能够稳定遗传。运用随机扩增多态性(Random amplified polymorphic DNA,RAPD)技术对其DNA多态性进行研究发现,辐照后突变体DNA与对照相比扩增条带或增加或减少,相似性系数为0.9513。综合结果表明,碳离子束辐照对大豆当代产生了一定的诱变效应,不仅造成了农艺性状的变异,而且使DNA水平也发生了明显的变化。     

Intensive irradiation of carbon nanotubes by Si ion beam

Multi-walled carbon nanotubes were irradiated with 40 keV Si ion beam to a dose of 1×10^7 cm^-2. The multiple-way carbon nanowire junctions and the Si doping in carbon nanowires were realized. Moreover, the formation processes of carbon nanowire junctions and the corresponding mechanism were studied.     

碳离子辐照诱导的甜高梁花粉生活力及花粉母细胞减数分裂的研究

为研究重离子辐照突变株的细胞遗传学变化,以碳离子辐照选育出的甜高粱早熟突变株KFJT-1及其对照品种KFJT-CK为材料,比较研究了两者之间花粉生活力大小以及花粉母细胞减数分裂的差异。结果发现：KFJT-1的花粉生活力以及花粉总数大于KFJT-CK;KFJT-1花粉母细胞减数分裂大多进入第二次减数分裂时,KFJT-CK花粉母细胞集中在第一次减数分裂;在KFJT-1减数分裂末期II,出现了两组分裂时期不一致、3分体以及不均等分裂畸变状况,畸变率仅为4．5％,说明KFJT-1在生长繁殖过程中修复了大部分由于物理诱变造成的染色体畸变,且能稳定遗传。这些结果从生殖细胞水平进一步说明碳离子辐照早熟突变株KFJT-1较未突变株KFJT-CK成熟期早,且各项指标均优于KFJT-CK。     

离子束诱变西瓜体细胞抗镰刀菌酸突变体研究

将通过能量为25keV、注量为6.24×1016/cm2的Ar+ 辐射处理后的三份西瓜种子接种在含有15mg / L镰刀菌酸(Fusaric acid,FA)的MS(Murashige, Skoog)培养基上获得无菌苗,以其子叶为外植体接种在MS+2mg/L 6-苄氨基嘌呤(Benzylaminopruine,BA)+15mg/L FA培养基上进行诱导生芽,将抗性再生芽转接到MS+0.2mg/L萘乙酸(Naphthylacetic acid,NAA)+15mg/L FA培养基上,进行抗FA的再生苗的生根诱导培养。结果表明,离子束辐射处理和FA对感病西瓜种子3-27和YH-5的发芽率及成苗都有显著抑制,两者的复合抑制作用更强;离子束辐射处理过的两个感病西瓜种子抗FA的芽诱导再生率和生根诱导率都高于对应的不经过离子束辐射处理的对照材料,提高幅度在材料之间、芽再生和根再生之间有差异。     

Preparation of cobalt nanoparticles by electron beam irradiation

and laser mattering particle size distribution analysis. Average size of the nanoparticles was about 32 nm with a narrow size distribution. Melting point of the nanoparticles was about 451.3 ℃.     

12C离子束辐照对酵母发酵能力的影响

利用100MeV/u的12C6+离子束辐照酵母Saccharomyces cerevsiea YY,选育出一株高产突变菌株C03A,考察C03A发酵过程中不同温度、pH、糖汁浓度对发酵的影响。通过正交实验确定最佳发酵条件为:糖汁浓度24%、温度35℃、pH5.0。在10L发酵罐实验中,C03A发酵速率相对原始菌株高,36h发酵完全,比原始菌株缩短12h;发酵产酒率达到13.2%(V/V),比原始菌株高1.6%(V/V)。     

Structural change of carbon nanotubes produced by Si ion beam irradiation

Multi-walled carbon nanotubes (MWCNTs) were irradiated by 40 keV Si ion beam with different doses. The structural change of the MWCNTs was revealed by transmission electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy. The structural characterization after irradiation shows that the formation of amorphous carbon nanowires proceeds through two periods, carbon nanotube – semi-solid amorphous carbon nanowire with hollow structure – solid amorphous carbon nanowire. Based on the interaction between energetic particles and carbon nanotubes, the structural transformation process and corresponding mechanisms are discussed. A model is presented to illustrate the structural change of carbon nanotubes with increased irradiation dose.     

Pigment analysis of a color-leaf mutant in Wandering Jew （Tradescantiafluminensis） irradiated by carbon ions

Many mutants of plant induced by heavy ion beam irradiation have been reported in recent years,but leaf anthocyan mutants induced by ion irradiation in evergreen were rarely found.In this study,a color-leaf mutant with purple leaves,stems and petals was isolated from clones of Wandering Jew irradiated by 95.8 MeV/u carbon ion beam.The concentration and histological distribution of leaf pigment were surveyed in wild type and mutant.In mutant,contents of total chlorophylls (Chl),chlorophyll a (Chl a),chlorophyll b (Chl b) and carotenoids (Car) decreased significantly,while concentration of the anthocyanins was 6.2-fold higher than that of wild type.Further composition analysis of anthocyanins by electrospray ionization mass spectrometry (ESI-MS) indicated that the purple pigmentation of leaves in mutant was caused by accumulation of petunidin anthocyanin.Microscopic examination showed that most petunidin anthocyanin accumulated in the lower epidermis,and little in vascular parenchyma of mutant,while there was no pigment in wild type.Meanwhile,in spongy parenchyma of mutant we observed little Chl,which the wild type abounds in.In conclusion,the color-leaf mutant of Wandering Jew induced by irradiation of carbon ions was improved in ornamental value,and it could be contribute to variation in level,component and distribution of foliar pigment.The possible mutation mechanisms were discussed.     

碳纳米管的径向形变和集束效应

用２０ＭｅＶ质子束照射电弧放电生成碳纳米管样品后，用高分辨率透射电子显微镜观察辐照样品，观察到了与辐照有关的碳纳米管的集束现象，三个并行联结构的纳米管的电镜图表明由于范德瓦尔斯力的作用，纳米管内部的碳（００２）层受到挤压，层间距变小，纳米管发生径向形变。     

强脉冲离子束辐照混合陶瓷/NiCoCrAlY热障涂层研究

为提高高温合金的工作温度,一般在其表面涂覆由粘结过渡层和陶瓷隔热层构成的热障层.热障层的热稳定性决定了高温合金部件的寿命.为延长由部分稳定的ZrO2/NiCoCrAIY合金构成的热障层的服役寿命,采用强脉冲离子束对它们的界面进行辐照处理.本工作研究了不同参数的强脉冲离子束(IPIB)对不同厚度结构的靶的辐照混合效应,通过一系列分析测试研究,发现合适参数的IPIB辐照能够有效地在界面形成混合层,从而改善热障层在高温氧化环境中的高温耐久性.其中采用峰值能量300 keV,脉冲宽度65 ns,峰值流强密度250 A/cm2的IPIB单脉冲辐照后的样品获得最好效果.对其原因做了分析,认为在界面处形成特定元素分布的混合层在高温氧化条件下既能形成完整的保护层,又改善了层间晶格和热胀系数失配,减小了失配热应力,从而提高了热障层在高温氧化条件下的稳定性.