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2005年  第22卷  第2期

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核物理
超重核性质的新观点(英文)
任中洲
2005, 22(2): 153-166. doi: 10.11804/NuclPhysRev.22.02.153
摘要:
简单回顾了超重核的理论研究现状,讨论了形变对长寿命重核α衰变半衰期的影响。分析了相对论平均场模型的有效范围。强调了α衰变、结团放射性和自发裂变中应保持宇称守恒。提出了一些新观点。
Status of theoretical studies on superheavy nuclei is simply reviewed.We investigate the influence of nuclear deformation on halflives of α decay for
long lifetime nuclei beyond 208Pb. The range of the validity of relativistic meanfield model is analyzed and discussed. The conservation of parity in αdecay, clusterradioactivity, and spontaneous fission of nuclei is stressed. New views on the properties of superheavy nuclei are presented.
142-164Dy核的低能谱和电磁跃迁的相互作用玻色子模型
昭日格图, 白洪波, 张进富
2005, 22(2): 167-171. doi: 10.11804/NuclPhysRev.22.02.167
摘要:
采用IBM模型研究了^142-164Dy核的低能正宇称态的能谱和电磁跃迁。应用U(5)→SU(3)的简化哈密顿量较好地描述了它们的能谱和电磁跃迁。研究结果表明,该核基本属于U(5)→SU(3)的过渡核Spectra and E2 transition rates for the eveneven 142-164Dy isotopes are studied in the framework of the interacting boson model. A schematic Hamiltonian capable of describing their spectra and transition is used. It is found that the eveneven 142-164Dy isotopes are in the transition from U(5)to SU(3) dynamical symmetry.
稀土区奇奇核πh1/2×vi13/2带B(M1)/B(E2)比值增强特性
陆景彬, 刘运祚, 孙亮, 杨东, 梁国栋, 王守宇, 马英君, 赵广义, 李险峰, 崔兴柱, 李明非, 霍俊德, 曾国模, 竺礼华, 吴晓光
2005, 22(2): 172-179. doi: 10.11804/NuclPhysRev.22.02.172
摘要:
在稀土区奇奇核πh1/2×vi13/2转动带中,系统地观测到随转动频率或角动量增加,B(M1)/B(E2)曲线表现出所谓parabola-1ike形状,即在增加到某一转动频率或自旋后,B(M1)/B(E2)比值快速增强。基于推转模型和粒子转子模型关于奇奇核二准粒子转动带磁偶极约化跃迁几率的描述,对稀土区双奇核的这一行为进行了讨论。指出该现象的发生与vi13/2准中子转动顺排特性密切相关。B(M1)/B(E2)比值在接近第二带交叉(即BC准中子对顺排)的较高频率处的增强效果,可以理解为主要来源于带交叉引起的波函数中混合四准粒子成分的结果。通过对B(M1)/B(E2)比值的增强效果发生在较低频率处的分析,对稀土区奇奇核πh1/2×vi13/2带角动量耦合图像有了进一步认识。
It is systematically observed that the B(M1)/B(E2) plots with the increasing of rotational frequency, behaves as a socalled parabolalike shape in the π h11/2 νi13/2 bands of rareearth doubly odd nuclei (i.e., the B(M1)/B(E2) ratios increase rapidly after a certain rotational frequency). Such a phenomenon is discussed based on the formula of magnetic dipole reduced transition probability deduced from the Cranking Shell Model and Particle Rotor Model respectively. It is pointed out that, the occurrence of this behavior is closely related to the alignment nature of the νi 13/2 quasineutron. The increasing of B(M1)/B(E2) occurring at large frequency approaching the second BC crossing can be understood as mainly resulted from the mixing of wave function with the 4 quasiparticle band caused by the band crossing. Insight into the angular momentum coupling scheme between the quasiparticles and collective core in the πh11/2 νi 13/2 structures of rareearth doubly odd nuclei is gained by analyzing the increasing behavior of B(M1)/B(E2) ratios occurring at low rotational frequency.
加速器
对于自共振激光加速器中轴向场问题的讨论
张德兴
2005, 22(2): 180-185. doi: 10.11804/NuclPhysRev.22.02.180
摘要:
从洛仑兹力方程的旋量形式出发,讨论了电磁场中电荷运动的轴向电场和轴向磁场问题以及平面波的脉冲和Larmor功率。这些问题是研究自共振激光加速器的基础。
From the spinorial form of the Lorentzforce equation, the problems about axial electric field and axial magnetic field of charge motion in electromagnetic fields, as well as planewave pulse and Larmor power have been discussed in this paper. These problems are the foundation of studying the autoresonance laser accelerator (ALA).
HIRFL—CSR实验环电子冷却装置调试
卢旺, 杨晓东, 李杰, 冒立军, 王志学, 赵红卫, 燕宏斌, 张玮, 张军辉, V.V.Parkhomchuk, BINPElectronCoolerGroupe
2005, 22(2): 186-189. doi: 10.11804/NuclPhysRev.22.02.186
摘要:
HIRFL-CSR实验环电子冷却装置采用了能够产生空心电子束的电子枪。弯曲螺线管内采用了静电偏转电极,冷却段采用了独立的高精度螺线管串联产生纵向磁场的设计。测量了沿离子束运动方向冷却段磁场分布及磁场平行度、电子枪和收集器性能、300kV高压电源相关参数。结果表明,此装置达到了预期的设计目标。
: In CSRe electron cooling device, a special electron gun which can produce variable profile electron beam with different size and density distribution was adopted for decreasing ion losses. Electrostatic bending device was used for reducing electron beam losses and improving vacuum condition. The instability of the electron beam is suppressed because the secondary electrons from collector would come back to the collector in the same orbit finally. Longitudinal magnetic field with parallelism better than 10-4 was achieved by adopting of independent high precise solenoid coils at cooling section. In this case, the r.m.s deviations of the transverse magnetic field at cooling section in horizontal and vertical direction are 3.298×10-5 and 2.458×10-5 respectively. The characters of the gun and collector were investigated. The results were presented and indicate that it achieves the design purpose very well.
SFC的改进
王义芳, 吴德忠, 张小奇, 马力帧, 何源, 王兵, 赵建民, 吴翼健, 王志学, 唐靖宇, 赵红卫
2005, 22(2): 190-192. doi: 10.11804/NuclPhysRev.22.02.190
摘要:
根据兰州重离子加速器的注入器SFC运行20年来所发现的问题, 近几年进行了一次大的改造, 使其真空度、 磁场分布以及高频系统的状态都得到了明显的改善。 半年多的调束和运行实践表明这次改造是十分成功的。
交叉学科
载能团簇离子诱发的非线性二次离子发射
史平, 丁富荣#, 王尧, 聂锐, 马宏骥
2005, 22(2): 193-197. doi: 10.11804/NuclPhysRev.22.02.193
摘要:
载能团簇离子进入固体时, 由于集体相互作用,在入射路径上产生非常高的能量沉积密度。 实验发现, 载能团簇离子的作用结果并不等于团簇中各原子独立作用的总和, 而是具有非线性效应。 就二次离子发射而言, 这种非线性通常与团簇的能量、 团簇的大小、 离子的电荷态以及靶物质的结构有关。 通过研究二次离子发射有助于理解载能团簇离子与物质相互作用过程中的能量沉积与释放机制。
Using energetic cluster as projectile is a unique way to produce simultaneous impacts of several atoms and deposit extremely high energy density in a very small area. The cluster impingement on solids has exhibited some nonlinear effects not presented in collisions of individual atoms with those solids. The study of the secondary ion emissions can give insight into the energy deposition and relaxation steps of the clustersolid interaction. The dependence of the yields of secondary ion emission induced by clusters on the energy of clusters,cluster sizes,charge states and material structures of the targets was reviewed in this paper.
用MCNPx程序计算宽能谱中子雷姆仪的响应曲线
苏有武, 朱小龙, 李武元
2005, 22(2): 198-199. doi: 10.11804/NuclPhysRev.22.02.198
摘要:
利用MCNPx程序计算了宽能谱中子雷姆仪的响应曲线。计算表明,增加铅层对低能中子的响应没有明显的影响,但在高能区(几百MeV以上)宽能谱中子雷姆仪的响应与铅层的厚度有关。铅层厚度为0.6cm时响应比普通雷姆仪提高约3倍,当铅层厚度增加到1.2cm时响应高约5倍。虽然计算结果与ICRP建议书中的H^*(10)曲线相比还有一定的差别,但改变慢化体的结构对提高高能中子的探测效率是有明显效果的。
The responses of two extended neutron rein counters as function of neutron energy was ca1cuated Monte Carlo code,MCNPx,was applied in the calculations.Isotropic neutron incidence was employed.The results show that the neutron response is independent on thickness of lead 1aver at low energies,and it is clearly increased with thickness of lead layer at high energies.Although tt1e shape of the response curve does not completely agree with the H (10) curve in ICRP 74 report ,the resuhs obtained give good bases for the practical use of the new instrument in high—energy neutron fields
超热电子的产生与输运背向辐射的测量
王光昶, 郑志坚, 杨向东, 谷渝秋, 吴云波
2005, 22(2): 200-203. doi: 10.11804/NuclPhysRev.22.02.200
摘要:
报道了在20TWfs激光器上采用电子磁谱仪和光学CCD积分成像相机分别对激光固体靶相互作用在靶背方向产生的超热电子能谱及其光学渡越辐射进行的测量。能谱测量结果显示:超热电子能谱呈双温类麦克斯韦分布,拟合的温度分别为90和280keV,平均温度为185keV,这与已知的温度定标率较好地吻合。光学渡越辐射测量结果显示:光学渡越辐射是由于超热电子输运穿越固体靶所致,而辐射区域呈圆盘状、有发散角、有光强分布。如果考虑超热电子的产生和加热机制,则占主导地位的加热机制是共振吸收对电子的加热。
重离子诱导的质粒DNA双链断裂分布研究
王潇, 马秋峰, 靳根明, 李文建, 张红, 周利斌, 毛淑红, 邱嵘, 刘兵,
2005, 22(2): 204-207. doi: 10.11804/NuclPhysRev.22.02.204
摘要:
利用能量为7.2MeV/u氖离子束辐照体外质粒DNA:pUC18,采用恒场凝胶电泳结合多功能荧光成像系统研究了pUC18双链断裂片段的分布。证实了双链断裂片段分布的非随机性,结果还发现DNA断裂后片段的交联现象,而且交联片段的分布也是非随机的。
DNA is considered to be the most important and sensitive target in biological systems. In addition to the base damage, DNA strand breaks are the major lesion in the genome due to exposure to ionizing radiation. Mutation can be introduced to DNA as a result of enzymatic processing of DNA lesions or postirradiation replication. However, the mechanisms of radiationinduced mutations are not well clarified at the molecular level. To study the effect on the simple plasmid DNA of heavy ion is even predominant or more feasible. 
Plasmid pUC18 DNA was prepared and irradiated by neon beam (7.199 MeV/u). The fragment distributions were determined by quantifying the ethidium bromide fluorescence. It can be seen that the shape of the intensity distributions is vastly different for the used radiation Dose. The distribution produced shows an excess of fragments particularly in 3 000 and 10 000 Gy the size range between 20—40 kbp and 20—50 bp. This clustering of doublestranded fragments might be influenced by the higher order chromatin structure of genomic DNA. If so, DNA loop structures could correspond to the size range for which we observed DSB clustering. Further studies aim at elucidating the heterogeneity of DSB induction within the genome and investigate the influence of chromatin structure on the nonrandom fragment distribution.
人肝癌SMMC-7721细胞对低剂量γ射线辐射超敏感性的研究
金晓东, 李强, 李文建, 王菊芳, 郭传玲, 郝冀芳
2005, 22(2): 208-211. doi: 10.11804/NuclPhysRev.22.02.208
摘要:
研究了人肝癌细胞SMMC-7721在低剂量γ射线照射下超敏感性和增强的辐射抗性响应。选用对数生长期细胞接受0—6 Gy不同剂量的^60Coγ射线的照射。利用流式细胞仪对细胞进行分选计数,并用克隆形成法检测细胞存活率。发现SMMC-7721细胞存在低剂量辐射超敏感性和增强的辐射抗性响应,即在0—0.3Gy之间细胞表现出单位剂量杀伤增强现象,在0.3—1Gy细胞表现一定的辐射抗性,在1Gy以上,细胞的存活符合线性平方模型。
利用PCC技术预测γ射线对肝癌细胞的辐射效应
杨建设, 李文建, 赵靖, 高清祥, 王转子, 夏景光, 金晓东
2005, 22(2): 212-215. doi: 10.11804/NuclPhysRev.22.02.212
摘要:
利用早熟染色体凝集技术预测研究了γ射线对肝癌细胞SMMC-7721的辐射效应。结果表明,G1和G2期细胞内的染色单体和等点染色单体断裂数与照射剂量之间存在线性相关性,染色单体断裂总数与细胞存活率之间存在良好的线性相关性。说明辐射诱导的染色单体断裂可以作为预测SMMC-7721细胞内在辐射敏感性的指标,也可为临床诊断和治疗肝癌提供依据。
We investigate the radiation response of hepatoma cells SMMC-7721 by premature chromosome condensation (PCC) technique. A dose-dependent increase in radiation-induced chromatid/isochromatid breaks was observed in G1 and G2 phase respectively. A good relationship was found between cell survival and chromatin breaks.
低剂量辐射诱导hepG2细胞克隆存活和细胞周期适应性反应
夏景光, 李文建, 王菊芳, 郭传玲, 魏巍, 杨建设
2005, 22(2): 216-218. doi: 10.11804/NuclPhysRev.22.02.216
摘要:
以低剂量γ射线(0.05 Gy)预照射人肝癌细胞hep G2, 8 h后再用高剂量(3 Gy)照射, 测定了细胞的克隆存活率和细胞周期。 结果表明, 低剂量辐射预处理可诱导hep G2细胞产生克隆存活适应性反应, 并且有助于细胞通过G2/M期阻滞; 低剂量辐射诱导的克隆存活适应性反应与增强的通过细胞周期阻滞的能力之间有一定的相关性。
Human hepatoma cells hep G2 were irradiated with 3 Gy of γray 8 hours after primed with 0.05 Gy of γray, thereafter,cell survival and cell cycle were determined. The results indicated that both survival adaptive response and the enhanced ability to overcome G2/M arrest could be induced by preirradiation with low dose of γray. It is suggested that there is a certain correlation between the survival adaptive response and the enhanced ability to overcome cell cycle arrest.
辐射基因治疗在肿瘤治疗中的研究现状
闵凤玲, 张红
2005, 22(2): 219-224. doi: 10.11804/NuclPhysRev.22.02.219
摘要:
目前肿瘤基因治疗尚存在许多问题, 距临床应用还有相当的距离, 但是在传统的放疗、化疗和手术治疗的基础上, 辐射与基因治疗的有机结合在肿瘤治疗中却显示出可喜的前景。综述了近年来这一领域的研究进展, 探讨了这一疗法对肿瘤治疗的应用前景。
Although tumor gene therapy has a distance to clinical use due to some problems, the combination of irradiation and gene therapy holds much promise in cancer therapy based on the traditional radiotherapy, chemotherapy and surgery. We have termed this therapeutic radiogenic therapy. This review focuses on the group of radiogenic therapy that are either: ⑴ improvement of gene transfer efficiency by irradiation; ⑵ radiotherapy combined with cytokines gene delivery or enhancement of the immunity of tumor cells by transgene; ⑶ directly stimulated by radiation to produce either directly or indirectly cytotoxic agents; ⑷ increasing of radiosensitivity in gene therapy; ⑸ radioprotective gene therapyenhances radiation tumor killing effect while protecting the normal tissue and organs with transgene using transfer vector.
辐射诱导的DNA修复与细胞凋亡的ATP调控
周清明, 张红, #, 党秉荣, 李文建, 刘兵, 闵凤玲, 段昕, 谢漪
2005, 22(2): 225-228. doi: 10.11804/NuclPhysRev.22.02.225
摘要:
综述了DNA辐射损伤导致的细胞阻遏于G1期以及在该时期对DNA的修复活动, 提出了较大剂量辐射诱导的三磷酸腺苷不足导致细胞凋亡的假说, 并分析了细胞走向凋亡与修复的辨正关系。
DNA damage induced by irradiation,which makes the cell arrested at G1 stage and DNA repair being activated in this stage,are summarized. It is proposed that the deficiency of adenosine triphosphate which is induced by the larger irradiation dose, induces cell apoptosis. And the relationship of cell selecting repair and apoptosis is also analyzed.
特异性抗癌因子——凋亡素
魏巍, 苏旭, 李文建, 刘建香, 张红
2005, 22(2): 229-232. doi: 10.11804/NuclPhysRev.22.02.229
摘要:
凋亡素是一种抗癌因子, 能以非p53依赖性途径诱导不同类型人肿瘤细胞的凋亡, 不受Bcl2的抑制作用, 且对正常细胞不起作用。 根据凋亡素的肿瘤特异性, 可将其作为一种极具潜力的抗肿瘤生物制剂, 在人体内大量传递给肿瘤细胞, 有选择性地根除肿瘤细胞。 论述了凋亡素抗肿瘤细胞的作用机理, 并对其应用现状、 前景及进一步研究的主要问题予以简要评述。Apoptin is an anticancer gene. It can induce p53independent,Bcl2insensitive type of apoptosis in various human tumor cells,and fails to induce programmed cell death in normal cell. Because of having tumor specificity, apoptin can be transferred enough to tumorcell in vivo,selectly kill the tumor as a potential antitumor biological preparation. In this paper, we provide a brief review on the anticancer mechanism of apoptin, current status and application prospect, and the main issues in apoptin studies.