首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 359 毫秒
1.
依托兰州重离子研究装置(HIRFL),开展了3种不同氧化物弥散强化的16Cr-ODS铁素体钢的重离子辐照损伤研究,旨在探究氧化物颗粒结构参数(尺寸和密度)对材料辐照硬化和Ne离子辐照脆化效应的影响.采用6.17 MeV/u的Ni离子辐照和Ne离子,借助辐照终端的梯度减能装置在材料样品中产生了均匀的辐照损伤坪区.借助纳米...  相似文献   

2.
离子辐照可以改变二氧化硅(SiO2)的晶体结构和光学性质.采用645 MeV Xe35+离子辐照SiO2单晶,在辐照过程中,利用光栅光谱仪测量在200—800 nm范围内的光发射.在发射光谱中,观测到中心位于461和631 nm的发射带.这些发射带是弗伦克尔激子辐射退激产生的,其强度与辐照离子能量和辐照离子剂量密切相关.实验结果表明:发射光强随离子在固体中的电子能损呈指数增加.由于离子辐照对晶体造成损伤,发射光谱强度随辐照剂量的增加而降低.文中讨论了这些与晶体结构有关的发射带,结合能量损失机制讨论了激子形成和退激过程.快重离子辐照过程中发射光谱的原位测量对研究辐照改性具有重要意义,有助于揭示离子辐照引起晶体损伤的物理机制.  相似文献   

3.
聚合物材料的快重离子辐照效应   总被引:1,自引:0,他引:1  
简要介绍了快重离子辐照损伤的特点,通过与低电离辐射粒子辐照在聚合物材料中产生的效应的类比论述了快重离子辐照在聚合物材料中产生的效应及其研究现状 ,并结合快重离子辐照效应的应用展望了该领域未来的发展.The irradiation effects in polymers induced by swift heavy ions were reviewed in comparison with that induced by low ionization particles based on the characteristics of swift heavy ion irradiations. It is shown that bond breaking and cross linking, gas releasing, amorphization and carbonization of polymers depend strongly on the electronic energy loss. Besides special effects such as alkynes production, can be induced under swift heavy ion irradiation. The perspectives...  相似文献   

4.
基于荷能离子与固体相互作用特点,提出了一种新的制备光致发光材料的方法-- 高能重离子辐照. 用这种方法研究了SiO2薄膜的光致发光特性,发现高能84K r和40Ar离子辐照可在注碳SiO2薄膜样品中产生强的蓝-紫光发射带,掺杂碳增强了辐照样品的发光特性.  相似文献   

5.
基于荷能离子与固体相互作用特点 ,提出了一种新的制备光致发光材料的方法——高能重离子辐照 .用这种方法研究了SiO2 薄膜的光致发光特性 ,发现高能 84Kr和40Ar离子辐照可在注碳Si O2 薄膜样品中产生强的蓝-紫光发射带 ,掺杂碳增强了辐照样品的发光特性.  相似文献   

6.
高电荷态离子比普通的离子携带较高的势能,势能在材料表面的瞬间释放,能在材料表面形成nm量级的结构损伤。它在纳米刻蚀、小型纳米器件、纳米材料、超小尺寸半导体芯片制作、固体表面处理和固体结构分析等领域具有广泛应用前景。因此对高电荷态重离子(Xeq+)引起半导体材料表面(6H-SiC)纳米结构变形进行了研究。采用Xe18+和Xe26+离子,选取从11014到51015 ionscm-2逐渐递增的剂量,以垂直和倾斜60角两种入射方式辐照6H-SiC薄膜样品, 经原子力显微镜分析表明,辐照后的表面肿胀凸起。对于Xe18+离子辐照的样品,辐照区至未辐照区边界的台阶高度随离子剂量增加而连续增大,而对于Xe26+离子辐照的样品则先增加而后减小。在相同入射角和剂量条件下,Xe26+离子辐照样品形成的台阶高度大于Xe18+离子辐照形成的台阶高度,在相同离子和剂量的条件下,垂直照射时形成的台阶高度大于倾斜照射时形成的台阶高度。根据损伤机理和实验数据,首次初步建立了一个包括势能、电荷态、入射角和剂量等物理量的理论模型来预测高电荷态离子在半导体材料表面形成的纳米结构变形。暗示了高电荷态离子的潜在的应用价值及进一步研究的必要性。  相似文献   

7.
高电荷态离子比普通的离子携带较高的势能,势能在材料表面的瞬间释放,能在材料表面形成nm量级的结构损伤。它在纳米刻蚀、小型纳米器件、纳米材料、超小尺寸半导体芯片制作、固体表面处理和固体结构分析等领域具有广泛应用前景。因此对高电荷态重离子(Xeq+)引起半导体材料表面(6H-SiC)纳米结构变形进行了研究。采用Xe18+和Xe26+离子,选取从1×1014到5×1015 ions·cm-2逐渐递增的剂量,以垂直和倾斜60°角两种入射方式辐照6H-SiC薄膜样品,经原子力显微镜分析表明,辐照后的表面肿胀凸起。对于Xe18+离子辐照的样品,辐照区至未辐照区边界的台阶高度随离子剂量增加而连续增大,而对于Xe26+离子辐照的样品则先增加而后减小。在相同入射角和剂量条件下,Xe26+离子辐照样品形成的台阶高度大于Xe18+离子辐照形成的台阶高度,在相同离子和剂量的条件下,垂直照射时形成的台阶高度大于倾斜照射时形成的台阶高度。根据损伤机理和实验数据,首次初步建立了一个包括势能、电荷态、入射角和剂量等物理量的理论模型来预测高电荷态离子在半导体材料表面形成的纳米结构变形。暗示了高电荷态离子的潜在的应用价值及进一步研究的必要性。  相似文献   

8.
简要介绍了快重离子与固体相互作用研究的状况和快重离子引起固体电子发射的机制 ,讨论了电子能损导致原子位移的 3种微观模型 ,即“库仑爆炸”模型、“热峰”模型和“激发排斥”模型 ,简述了研究电子发射的实验测量装置和测量方法 ,讨论了总电子发射产额与电子能损的关系以及靶俄歇电子和快传输电子测量在电子激发诱发辐照损伤微观机制研究中的应用 ,并介绍了重离子在 C靶中产生的离子径迹处的电子温度和聚丙稀靶中离子径迹势的提取方法. The recent progresses in experimental and theoretical studies of the collision between swift heavy ion and solids as well as electron emission induced by swift heavy ion in solids were briefly reviewed. Three models, Coulomb explosion, thermal spike and repulsive long lived states, for interpreting the atomic displacements stimulated by the electronic energy loss were discussed. The experimental setup and methods for measuring the electron emission from solids were described ...  相似文献   

9.
一、前 言 离子注入工艺是把要注入的杂质元素电离 成离子.然后通过磁分析器分析和加速器加速, 得到较纯的离子,并以很快的速度,将这种离子 打入固体靶内,以达到改变固体表面的物理化 学性能.这种注入工艺早在五十年代就已进行 了大量的研究.当时的研究以金属为主。主要 是进行原子相互作用的物理探索,模拟反应堆材料的辐照损伤效应.在六十年代初·人们已 经知道半导体材料的电学性质,可以由辐照损 伤和射入快速离子而产生变化.掺杂的杂质量 只要10-5at%,就能使半导体的电学性质发生 显著的改变.这样小的掺杂量,对于离子注入 工艺是极为方便…  相似文献   

10.
用 Raman散射和 XPS技术分析了能量为几百 ke V到几百 Me V的多种离子在 C60 薄膜中引起的辐照效应.分析结果表明 ,在低能重离子辐照的 C60 薄膜中 ,其晶态向非晶态的转变过程是由核碰撞主导的.在快离子 (1 2 0 ke V的 H离子和171.2 Me V的 S离子 )辐照的情况下,电子能损起主导作用.发现在H离子辐照过程中,电子能损有明显的退火效应 ,致使 C60 由晶态向非晶态转变的过程中,经历了一个石墨化的中间过程;而在 S离子辐照的情况下 ,电子能损的破坏作用超过了退火效应 ,因此 ,在C60 由晶态向非晶态转变的过程中,无石墨化的中间过程.Irradiation effecs (mainly including transformation from crystalline into amorphous state) of C 60 films induced by 120 keV H, He, N, Ar, Fe and Mo ions, 240 keV and 360 keV Ar ions, and 171.2 MeV, 125.3 MeV and 75.8 MeV S ions were analysed by means of Raman scattering and XPS technique. The analysis results indicate that amorphization process in the cases of N, Ar, Fe and Mo ions irradiation is dominated by nuclear collision, but in the case of H ion irradiation, the process is...  相似文献   

11.
回顾了低能离子注入单晶Si经由核弹性碰撞引起的损伤特征及其常规的研究方法,介绍了快重离子辐照单晶Si经由电子能损引起的损伤特点及研究现状,并对该领域的研究作了展望. The radiation damage in silicon induced by low energy ion implantation was briefly reviewed together with a short introduction to the common techniques in the area. The damage characteristics of swift heavy ion irradiation in silicon and its investigations were introduced with emphasis on the effects induced by processes of electronic energy losses. It is shown that swift heavy ion can induce defects far beyond the projected range and up to 28 MeV/μm the electronic energy ...  相似文献   

12.
快重离子引起的塑性形变现象   总被引:2,自引:2,他引:0  
非晶材料在快重离子轰击下显示了奇异的各向异性的塑性形变 ,这是电子能损所引起的宏观可见的剧烈的原子重排 .这个效应不能发生在具有晶态结构的材料中 ,但发生于所有的非晶材料中 .这一宏观现象隐含了寻找原子尺度上电子激发转换成原子位移的潜在线索 ,因而受到广泛的关注 .在回顾了现象发现的历史之后 ,综述了离子束引起的塑性形变的基本规律、最新结果、实验方法和技术新的进展 ,最后讨论了相关的物理机制和唯象模型. A very peculiar effect occurring when an amorphous material is irradiated with swift heavy ion is the giant plastic deformation phenomenon discovered in the eighties by Klaumunzer[DD(-8/9]¨ It is macroscopically visible atomic rearrangements induced by electronic energy loss. This effect occurs only in truly amorphous solids and can not occur in a crystalline material. This phenomenon gives rise to a wide ranging and lasting research in the field of the interaction of swift heavy...  相似文献   

13.
Ran Huang 《中国物理 B》2021,30(8):86105-086105
Integrating nanowires with nonuniform diameter and random spatial distribution into an array can afford unconventional and additional means for modulating optical response. However, experimental realization of such a nanowire array is quite challenging. In this work, we propose a new fabrication strategy which takes advantage of ion track technology, via sequential swift heavy ion irradiation and ion track etching. Based on this strategy, we unprecedentedly realize nanowire arrays, using gold as an example, with gradient and programmable diameters in a controlled manner. We further demonstrate that such nanowire arrays can support broadband, tunable, and enhanced plasmonic responses. We believe that our new type of nanowire arrays will find great potential in applications such as light management and optoelectronic devices.  相似文献   

14.
重离子辐射植物的诱变效应研究及应用   总被引:5,自引:0,他引:5  
重离子生物技术已引起人们的广泛关注, 植物育种是重离子生物技术研究和应用的热点之一。 简要介绍了重离子的基本特征和在育种应用中的优势, 综述了重离子辐射对植物分子、 细胞、 个体3个水平的诱变效应研究及重离子辐射育种取得的进展。 Heavy ion biotechnology has received much attention since the mid 1980s, when the first mutagenic effect of heavy ion beams was found in rice. Since then, plant breeding is one of the focuses in heavy ion biotechnology. In this paper we outlined the recent developments in plant breeding by heavy ion beams. We introduced briefly the essential characteristics and superiority of heavy ion beams applied in plant breeding, and reviewed further the mutagenic research in three levels(e.g., molecular, cell and individual) of plants. At last, we summarized artificial mutants obtained in plants irradiated by heavy ion beams.  相似文献   

15.
利用兰州重离子研究装置(HIRFL) 提供的高能12C6+离子束(能量为300 MeV/u,剂量率为0.5 Gy/min) 辐照大鼠离体胸主动脉环,考察了12C6+离子束辐照对主动脉环内皮依赖性舒张功能的影响,并采用NBT 还原法测定血管环生成超氧阴离子(O2􀀀) 水平,加入外源性超氧化物歧化酶(SOD) 干预探讨了O2􀀀在内皮功能损伤中的作用。研究结果表明,2.0,4.0 和6.0 Gy 的12C6+离子束辐照大鼠胸主动脉环后,可致血管内皮依赖性舒张功能的剂量依赖性明显受损(P <0.01 vs control group),并可致血管环NBT 还原能力剂量依赖性增加(4.0 Gy 时,P <0.05;6.0 Gy 时,P <0.01 vs control group)。辐照前加入外源性SOD 对6.0 Gy 12C6+离子束辐照所致血管环NBT 还原能力升高有明显抑制作用(P <0.01),对血管环内皮依赖性舒张功能也有明显的保护作用(P<0.01),但辐照后10 min 加入外源性SOD,其保护作用明显不及前者。结论显示,12C6+ 离子束辐照大鼠胸主动脉环可致血管内皮功能受损,O2 清除剂SOD 对内皮功能受损有保护作用,说明O2􀀀介导了辐照所致内皮功能损伤。Heavy ion beam has many characteristics,and it is expected to be the most suitable radiation therapy technique for malignant tumor. It is lack of depth-understanding on the potential adverse reactions caused by using this technique, because heavy ion radiotherapy is applied to clinical for a short time. Studies have shown that the vascular injury plays a pivotal role in normal tissue damage induced in the conventional radiation therapy, but there was no research report on heavy ion beam irradiation-induced vascular injury. In the present study, the isolated aortic rings of rats were irradiated by 12C6+ ion beam (300 MeV/u, 0.5 Gy/min) delivered by HIRFL(Heavy Ion Research Facility in Lanzhou), the effects of 12C6+ ion beam irradiation on aortic rings with endothelium dependent diastolic function have been investigated.NBT reduction method was used for assaying the vascular ring formation of superoxide anion (O2􀀀) level, and the involvement of superoxide anion in endothelial function injury in rats was investigated through the intervention test of exogenous superoxide dismutase (SOD) on O2. The results showed that, the vascular endothelial dependent vasodilation was impaired significantly (P < 0:01 vs control group) by irradiation with 2.0, 4.0 and 6.0 Gy 12C6+ ion beam in a dosedependent manner, and the NBT reduction of vascular rings increased dose-dependently (P <0.05 at 4.0 Gy, P <0.01 at 6.0 Gy vs control group). Adding exogenous SOD before irradiation could significantly inhibit the increasing of NBT reduction (P<0.01), and also had protective effect on vascular endothelium dependent diastolic function (P<0.01), but 10 min after irradiation with exogenous SOD, its protective function was significantly less than before. Conclusion indicated that 12C6+ ion beam irradiation could cause endothelial function impaired, O2􀀀 scavenger SOD has a protective effect on endothelial dysfunction, suggesting that O2􀀀 mediates endothelial injury induced by heavy ion irradiation.  相似文献   

16.
This article reports micro‐Raman experiments performed on cross sections of 6H‐SiC crystals irradiated with heavy ions of different energies. The results demonstrate that this technique is very powerful to quantify the damage created in the wake of energetic ions from the surface of samples down to the ion resting position. For slow ions (900‐keV I), ballistic collisions lead to the amorphization of the surface region of samples. For swift ions (36‐MeV W), the surface region remains crystalline and amorphization occurs around the end of the ion path. Moreover, synergistic effects between electronic and nuclear slowing down processes are put forward. The methodology used in this work may be adapted to other materials where radiation effects need to be investigated, provided that the damage created by irradiation is detectable by Raman spectroscopy. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

17.
ABSTRACT

The damage production induced by swift heavy ion irradiation in single-layer graphene (SLG) is investigated by molecular dynamics method. By given energy to a cylindrical region, the latent track consisting of nanopore and non-six-member rings can be produced, which depends on the electronic energy loss (dE/dx). For SLG, the minimum value needed to generate defects lies in 6.5–10?keV/nm. The latent track formation begins with the decomposition of the structure in energy deposition region until the atomic fragments escape from the surface and gradually decompose into atomic clusters. At the same time, the structure of system also changes. The source power of this phenomena is the accumulation and outward propagation of atomic stress in energy deposition region.  相似文献   

18.
Development of nanostructured materials has become of wide interest due to their exotic properties and interesting physics aspects. Energetic ions play a crucial role in the development of nano materials. Ions of different energy regimes have different roles in growth of nano particles. Low energy ions (typically up to a (kiloelectronvolt) keV) in plasma, have been in use for growth of nano particle thin films. Low energy ions (typically a few hundred (kiloelectronvolt) keV) from ion implanters are used for growth of nano particles in a matrix. High energy heavy ions (swift heavy ions) have been in use in recent years for growth of nanostructures and also for modifying nanostructures. Highly charged slow moving ions and focused ion beams too, have potential for creating nanostructures. Out of these several possible roles of energetic ions, there have been developments at NSC Delhi in growth of nanostructures by RF plasma, low energy ions and swift heavy.  相似文献   

19.
离子束辐照拟南芥生物学效应及其分子机理研究进展   总被引:2,自引:1,他引:1  
综述了离子束辐照拟南芥种子生物学效应、 生长发育变化、 向重力性等研究的最新进展。 阐释了离子束辐照拟南芥染色体DNA碱基变化、 DNA断裂或损伤、 染色体重组、 突变遗传性等分子机理。 探讨了离子束介导外源基因转化拟南芥的有效性和机理。 同时展望了辐照拟南芥分子机理研究中的辐射原初效应传递、 信号转导等其他机理研究及重离子辐射生物学效应的应用前景。 Newly research progresses were summarized in effect of ion beams on seed surface, biological effect, growth, development, gravitropism and so on. Furthermore, mutation molecular mechanism of Arabidopsis thaliana was discussed, for example, alteration of DNA bases, DNA damage, chromosomal recombination, characteristics of mutant transmissibility, etc. Meanwhile, the achievements of transferring extraneous gene to Arabidopsis thaliana by ion beams were reviewed in the paper. At last, the future prospective are also discussed here in mutation molecular mechanism and the potential application of biological effect of heavy ion beams.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号