高能重离子辐照制备SiOC复合材料的研究

用120 kev碳离子注入非晶SiO2薄膜,再用高能Xe、Pb和U离子辐照.注碳剂量范围为2.0×1017-8.6×1017 cm-2,高能离子辐照剂量1.0×1010-3.8×1012 cm-2.辐照后的样品用傅里叶变换红外光谱仪进行系统分析.实验结果显示,高能离子辐照在注碳非晶SiO2薄膜中形成了大量的Si-O-C键和Si-C键.这些Si-O-C结构具有环链、开链和笼链等多种结构形式.随电子能损、辐照剂量或者沉积能量密度的增加,SiOC结构由类笼向环/开链结构演化.对高能重离子驱动产生SiOC结构的机理进行了简单的讨论.     

重离子束辐照细胞研究的文献计量学分析

应用文献计量学方法和相应的应用软件,借助Web of Science平台对重离子束辐照细胞这一研究主题的相关文献、作者、期刊、机构以及关键词进行定量和系统考察。结果显示,重离子束辐照细胞研究在1990年之后日益活跃并深入;不同品质的重离子束辐照诱导不同类型细胞会产生不同的生物学效应、旁观者效应及其机制、重离子束辐照细胞生物学效应评估模型、重离子束治疗癌症过程中辐照品质选择与控制模型以及相应的计算机程序是该研究主题的重要内容;引入特定指数推测所得该研究主题重要学术期刊与Nature,Proceedings of the National Academy of Sciences of the United States of America,Cancer Research等期刊之间有较高的共被引频次,表明更多科学前沿的突破性成果和思路应用于该主题研究中;此外,该研究主要集中于少数国家、少数机构、少数作者,并且合作相对较少。     

离子注入与离子束混合两用机

早在1979年,为了解决应用于高温高真空环境下的轴承的自润滑问题,我们就着手采用     

Analysis of products of thymine irradiated by ^18O^8＋ ion beam in N2O saturated aqueous solution

Some methods of capillary gas chromatography,such as GC,GC-mS,GC-FT-IR,are used to analyze the products of thymine irradiated by ^18O^8 ion beam in N2O saturated aqueous solution.From the results of GC-MS the molecular weight of products can be determined,and from the results of GC-FT-IR some molecular structure information of products can be obtained.By this way the products,5,6-Dihydrothymine,5-Hydroxyl-5-Methylhydantoin,5-Hydroxyl-6-Hydrothymine,5-Hydro-6-Hydroxylthymine,5-Hydroxymethyluracil,Trans-Thymine glycol,Cis-Thymine glycol and dimers are dtermined without separation of them from sam,ples.Though these products are as same as those products of thymine irraduiated by γ rays in N2O saturated aqueous solution,the mechanism of thymine irradiated by heavy ion beam in aqueous solution is differrent from that by γ rays.The main products of thymine irradiated by ^18O^8 ion beam in N2O saturated aqueous solution are hydroxyl adducts at 5-6 band of thymine,while the main products of thymine irradiated by γ ray in N2O staurated aqueous solution are dimers of thymine.     

Medium energy ion irradiation capability for studies of radiation damage effects over a wide temperature range

In this report, we present preliminary ion irradiation experiments performed using a new medium energy (up to ∼20 MeV), high temperature ion irradiation capability that we developed at Los Alamos National Laboratory. Details of ion fluence and irradiation temperature (including ion beam heating) control, measurements procedure and accuracy are described. In particular, we investigated irradiation-induced atomic intermixing in a layered structure composed of MgO and HfO₂ thin films deposited on a sapphire substrate. This multi-layered structure represents a dispersion nuclear fuel form surrogate. To simulate a nuclear reactor environment, we performed ion irradiation using 10 MeV Au ions to a fluence of 5 × 10¹⁵ cm⁻² at a substrate temperature of 1000 °C. The degree of atomic intermixing was assessed from depth profiles of Mg, Hf, and Al atoms, which were obtained using Rutherford backscattering spectrometry. We found considerable interlayer mixing for sample regions in close proximity to the sapphire substrate.     

GaN基LED高能电子束流辐照效应研究

使用高能电子辐照对GaN基蓝光发光二极管(Light Emitting Diode,LED)光电学性能的影响进行研究。高能电子束流分别对不同组别的LED样品进行辐照实验,并通过自动测控系统对辐照过程中LED的电流、光强、光谱峰值波长进行全程测控。随后,在室温无辐照环境下对上述不同组别的LED样品进行跟踪对比测试研究。实验结果表明,高能辐照对LED的改性有明显效果,具体表现在工作电流和发光功率变化时受辐照影响的稳定性有所改善,光谱峰值波长出现蓝移。同时,GaN基LED在辐照过程中是否通电对LED的光电学性能有显著影响。     

Phoswich探测器的重离子束测试

利用一套由１ｍｍ厚的ＰＩＬＯＴ－Ｕ和４０ｍｍ厚的ＮＥ１１５塑料闪烁体组成的Ｐｈｏｓｗｉｃｈ（光叠层望远镜）探测器测量了４０Ａｒ（２５ＭｅＶ／ｕ）＋１９７Ａｕ反应中出射的产物，粒子鉴别采用Ｐｈｏｓｗｉｃｈ的快慢成分方法．结果表明该方法能清楚地分辨出粒子的电荷．对Ｚ＝１的粒子，ｐ、ｄ和ｔ亦能分开．     

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。     

重离子辐照柠檬酸菌株的诱变选育

应用不同剂量重离子束12C+6对黑曲霉出发菌株4﹟进行辐照选育,选育出的高产酸菌株进行发酵试验,应用酸碱中和法测定发酵液中柠檬酸的含量。结果表明:当重离子12C+6的辐照剂量为60 Gy时,正突变率最大,为21%。诱变后的菌株通过酸斑法初筛、摇瓶复筛选育出1株菌株H4002,其发酵液中柠檬酸含量比出发菌株4﹟提高了18%。这说明利用重离子束12C+6辐照处理黑曲霉产生菌可以得到高产柠檬酸突变菌株,其诱变效果显著。     

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)。     

Physiological property and yield of the sweet sorghum mutants induced by heavy ion irradiation

Soil salinity can limit plant growth and productivity. The cultivation of tolerant varieties is convenient and cost-effective for making good use of the saline soils.The sweet sorghum plant has a high tolerance for saline alkaline soils. The KF1210-3 and KF1210-4 early-maturity mutants of sweet sorghum were obtained via carbon ion irradiation. The study assesses the productivity of three sweet sorghum cultivars(KF1210-3, KF1210-4, and KFJTCK) which were grown in intermediate(4.6 d S m~(-1)) and high(11.9 d S m~(-1)) soil salinity. The sweet sorghum grown in the soil salinity of 4.6 d S m~(-1)produced 50.00–57.30 %greater fresh weight than that in the soil salinity of11.9 d S m~(-1), while the difference was not as obvious among the dry biomass of the three sweet sorghum cultivars. Moreover, the Brix degree of the sweet sorghum grown in the soil salinity of 11.9 d S m~(-1)was greater than that grown in the soil salinity of 4.6 d S m~(-1). The heavy ion irradiation experiment is of great significance in screening plant mutants, improving environmental conditions, and assessing the productivity. This process, in turn, aids in the understanding of the effects of the biochemical and physiological mechanisms of salt stress.     

重离子束均匀度的测定及治癌束流成形的模拟试验

采用５０μｍ厚聚碳酸酯薄膜，利用核径迹测技术测得φ４０ｍｍ的２５ＭｅＶ／ｕ＾４０Ａｒ＾１４＋离子束的均匀度在散焦情况下为３２．７％，在Ｄ“散焦＋样品旋转”情况下为５２．４％。还采用多层聚碳酸酯薄膜组件作为肿瘤块等效材料，进行了重离子束治癌束流成形模拟试验。     

Inhibition of mouse tumors by heavy ion irradiation

1IntroductionCancertreatment'withheavyionsisahighteclmiqueincurrentradiotherapy.Itisoneofthemosteffectivemethodsinthecancertreatment.Duringthecoddle1970s)thegroupatLawrenceBerkeleyLaboratory(LBL)succeededinmodifyingandconnectingitsealstinglow-energyheavy-ionaccelerator(HILAC)toahigh-energyprotonaccelerator(Bevatron)toobtainheavy-ionbeamssuitableforradiotherapy.ThiscombinedfacilitywasknownastheBEVALAC.450patientsweretreatedwithheavyions,mostlyneonattheBevalacofLBL[1].Thegroupreportedp…     

Development of function-graded proton exchange membrane for PEFC using heavy ion beam irradiation

The graded energy deposition of heavy ion beam irradiation to polymeric materials was utilized to synthesize a novel proton exchange membrane (PEM) with the graded density of sulfonic acid groups toward the thickness direction. Stacked Poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) films were irradiated by Xe⁵⁴⁺ ion beam with the energy of 6 MeV/u under a vacuum condition. The induced trapped radicals by the irradiation were measured by electron spin resonance (ESR) spectroscopy. Irradiated films were grafted with styrene monomer and then sulfonated. X-ray photo-electron spectroscopy (XPS) spectra showed that the densities of sulfonic acid groups were controlled for injection “Surface” and transmit “Back” sides of the fabricated PEM. The membrane electrode assembly (MEA) fabricated by the function-graded PEM showed improved fuel cell performance in terms of voltage stability. It was expected that the function-graded PEM could control the graded concentration of sulfonic acid groups in PEM.     

80 MeV/u C-12离子诱变选育PHB高产菌株

用80MeV/u12C6+离子对一株积累聚β-羟基丁酸酯(PHB)的芽孢杆菌(BacillusP-9)进行诱变选育,最终获得PHB高产株菌G15,其PHB产量达2.93g/L,与出发菌株相比较,PHB积累量提高了1.5倍。研究结果表明,本试验辐照最佳剂量为15Gy。重离子辐照诱变育种效果显著,具有广阔的发展应用前景。     

重离子束的Bragg峰定位于麦粒的自由基探针技术

为了实现定点定位诱变，提出了一种利用ＥＳＲ波谱术对离子束Ｂｒａｇｇ峰在麦粒中的定位方法，即自由基探针技术，采用该技术有效地测定出２１ＭｅＶ／ｕ氮离子束的Ｂｒａｇｇ峰位于小麦胚部，注入深度不超过１．０±０．２ｍｍ，而４８ＭｅＶ／ｕ氮离子束贯穿全麦粒，不能实现定点定位诱变。     

High temperature oxidation resistance of fluorine-treated TiAl alloys: Chemical vs. ion beam fluorination techniques

The modification of the alloy surface by halogens significantly improves their oxidation behaviour at high temperature. It corresponds to the preferential reaction of the aluminium with the applied fluorine at the oxide/alloy interface and it promotes the growth of an adherent and stable alumina layer.Well-defined fluorine profiles beneath the surface of the material can be achieved by either fluorine beam line ion implantation (BLI²) or plasma immersion ion implantation (PI³). As an alternative to the implantation-based approach, chemical fluorination techniques such as gas-phase treatment and dipping in F-based solutions were also investigated. The fluorine depth-profiles were measured before and after oxidation at 900 °C using non destructive ion beam analyses: Proton Induced Gamma-ray Emission (PIGE), Rutherford Backscattering Spectroscopy (RBS) as well as Elastic Recoil Detection Analysis (ERDA). It enables to control and to optimise the fluorination conditions of technical TiAl alloys for an industrial application.     

高功率离子束模拟材料的X射线热-力学效应研究

主要介绍了利用高功率离子束模拟1keV黑体辐射X射线对材料的热—力学效应(thermal—mechanical effects)的初步研究结果。计算了“闪光二号”加速器产生的高功率离子束(质子束)和1keV黑体辐射X射线在材料中的能量沉积剖面，计算结果表明二者的能量沉积范围和剖面变化趋势基本一致。给出了利用“闪光二号”加速器高功率离子束辐照不同材料样品的初步实验结果。所辐照的样品表面镀层被剥离掉，Cu和Al样品表面有明显的熔融痕迹，样品的质量损失约几十毫克，3mm厚的石墨样品碎裂成数块，1mm厚的Al靶形变达到6mm。实测的5mm厚硬Al靶背面应力波峰值约35MPa。因而可以利用“闪光二号”加速器产生的高功率离子束模拟1keV黑体辐射X射线的热—力学效应。     

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。     

NFZ-10工业辐照电子直线加速器束流控制方法

在ＮＦＺ－１０工业辐照电子直线加速器上,分析了以输出束流来负反馈控制轰击型二极电子枪灯丝电压进而稳定输出束流的方法及存在的缺点。提出了新的控制轰击高压的方法,在此加速器上得到了高稳定性和高精度的输出束流。