Prospects of Ion Chemical Reactions with Heavy Elements in the Gas Phase

Heavy element chemistry is related to the fundamental interest that lies in exploring the upper limits of the periodic table. Chemical properties of the heaviest elements have already been studied at single atoms in aqueous solutions and in the gas phase up to an atomic number Z = 107. These techniques allow to study nuclides with half lives as short as about 1 s. Next generation chemistry experiments could be envisaged with an ion trap technique already developed for stable isotopes. At very low production rates in the order of 1 per 100 s and/or half lives as short as about 10 ms, the ion-molecule reactions can be studied in a buffer gas cell, in which the heavy elements are stopped and thermalize with a high probability as singly charged ions. Ion-molecule reactions with well defined buffer gas admixtures, as, e.g., O₂, H₂O, CH₄, CO₂, are identified by mass selective detection. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ion Mobility Measurements of Carbon Tetrachloride

Abstract

The ion mobility and drift velocity of carbon tetrachloride have been measured at various ratios of E/P_o, ranging from 1.0 to 9 volts/ (cm-Torr). The technique employed for these measurements utilizes a polonium alpha particle source which serves both as the source for ionization as well as the means for producing a reference pulse from a solid state silicon barrier detector. The thermal electrons which are produced are readily captured by carbon tetrachloride and the resulting negative ion, assumed to be CC1₄ ^?, is detected by means of a proportional counter located at the end of the drift path. The zero field reduced mobility obtained for CC1₄ ^?was 0.42 cm²/(volt-sec). The nature of the ionic species is explained in terms of the quantum mechanical theory of ionic mobility as put forth by Dalgarno.     

重离子治癌装置研究

介绍了重离子治癌装置的最新发展状况 ,比较了两类典型的旋转机架的结构及光学特性 ,给出了离子光学的限制条件 .设计了一台桶形机架 ,为兰州重离子冷却储存环应用于医学治疗进行了预研. A simple plane rotating gantry is proposed at the Heavy Ion Research Facility in Lanzhou (HIRFL), where a new project named Cooling Storage Ring is under construction. The gantry is 18 metre long, 5 metre high from upper beam axes to rotation axes. It consists of eight quadruples, two 45° and one large aperture 90° dipole magnets. It is equipped with a two direction magnetic raster scanning system. A beam spot of radii between 2 to 5 mm can be achieved at∶...     

Ion Mobility Spectrometry: Principles and Applications

Abstract

General principles are reviewed for ion mobility spectrometry including new methods for ion separation through field dependent mobilities in strong electric fields with high frequency asymmetric waveform. Additionally, recent advances in the instrumentation for the characterization of ion mobilities in air at ambient pressure are described and critically reviewed. Advances in instrumentation, understanding of principles of measurements by IMS, and the development of hyphenated technologies have resulted in an increase in the number of applications in recent years.     

Recent Developments in Ion Mobility Spectrometry

Abstract

The general principles and technical implementations of traditional time-of-flight ion mobility spectrometers and analyzers with field-dependent mobilities were reviewed in our last article in this journal. Recent advances in instrumentation and new applications since 2006 are highlighted in this review. In addition to traditional applications as military chemical-agent detectors, ion mobility techniques have become popular for different purposes. Though ion mobility spectrometry was solely used as vapor sensor in the past decades, further developments in ionization techniques (especially electrospray ionization) now permit its routine use for the analysis of liquid samples. The coupling of ion mobility spectrometry with selective sample preparation techniques such as molecular-imprinted polymers, coupling with chromatographic techniques, the use of dopants, and application of selective ionization sources has led to an expanded number of applications in industrial and environmental analysis with complex sample matrices due to an improved selectivity in comparison with traditional stand-alone spectrometers. Furthermore, new developments in hyphenated techniques, especially ion mobility–mass spectrometry couplings, has resulted in an increased number of new applications for the analysis of biomolecules and pharmaceutical samples and in clinical diagnostics.     

重离子熔合反应与双核模型

简单介绍了兰州-北京-吉森合作组对合成超重核的重离子反应进行的初步研究。研究的重点是熔合阶段的反应机制。在原有双核模型的基础上做了一些改进,把耗散相对运动过程与核子转移过程耦合起来,从更微观的角度来描写双核系统向全熔合复合核的演化。在双核过程中的每一步求解主方程,不对驱动势做谐振子近似。同时,还探讨了原子核形变与相对取向对驱动势的影响,存活几率与复合核蒸发中子的奇偶效应,以及入射道中原子核非弹性激发对俘获截面的影响等。In recent years, the Lanzou-Beijing-Giessen collaboration has studied the heavy ion reactions which are lead to the formation of super-heavy nuclei. The study emphases the mechanism of the fusion stage of the reactions. Based on the so called Di-nuclear System Model, some improvements have been made. The main points are the coupling of the dissipation of relative motion energy, angular momentum with nucleon transfer, and solving the Master equation in every step of the nucleon transfer with exact driving potentials, in order to describe the evolution of the system more microscopically. At the same time, we also discussed the effects of nuclear deformation and their relative orientation on the driving potentials, and studied the survive probability of the compound nuclei and its old-even effects, as well as the influence of inelastic excitations of nuclei in entrance channels to the capture cross sections.     

重离子反应中的集体转动效应及反应特征

研究了重离子反应中的集体转动效应及反应特征.给出了反应最大碰撞参数、碰撞中心度、平均集体转动能以及转动角速度等表征反应特征的物理量.对10.6MeV/u ⁸⁴Kr+²⁷Al→¹¹¹In裂变反应研究表明,该反应具有高的碰撞中心度,集体转动能约占总激发能的1/3,系统在裂变前转动了约8.8圈.     

π弦在重离子碰撞实验中的效应

在能量为s=5.5TeV的LHCPb?Pb重离子碰撞实验中,研究了和手征相变相关的π弦的可观测效应.利用Kibble-Zurek机制讨论了π弦的产生和演化.在LHCPb-Pb重离子碰撞实验中,如果手征相变发生并且是二级相变,那么π弦将会产生然后衰变.π弦的主要效应是:π弦衰变成大量的末态π粒子,这些大量的π粒子,主要分布在动量为143MeV的低动量空间;同时π弦的衰变还伴随着大量中性π粒子,这些中性的π粒子主要分布在动量为21MeV的低动量空间.     

超相对论重离子碰撞中小相对动量区域2π干涉学

用小相对动量区域π干涉学方法给出了超相对论重离子碰撞中两种模型下π源参数的关系,并与200A GeV O+Au碰撞的实验结果进行了对比.     

低能重离子剂量-存活率效应及其拟合模型探讨

低能重离子注入生物体是20世纪80年代中期发展起来的一种诱变手段, 在诱变育种和放射医学等领域有巨大的应用前景。 物理辐照的剂量与存活率之间的关系是辐射生物学效应的最重要的关系之一, 低能离子与生物体相互作用的剂量 存活率曲线表现为特殊的马鞍型。 介绍了低能重离子的马鞍型剂量 存活率效应及其数学模型, 并探讨了模型拟合中存在的一些问题。 Low energy heavy ion implantation is an organism mutation method developed in middle of 1980s, which has a potential application in breeding and radiation therapy. The dose survival curve is a characteristic effect in radiobiology. Implanted with low energy heavy ions, organisms could manifest a Saddle like dose survival curve. In this article, the Saddle like dose survival effect and its modeling has been described, and several topics in model simulation are discussed.     

蛋白质组学及其在重离子治癌应用中的探讨

综述了蛋白质组学的主要方法和技术——双向凝胶电泳、生物质谱技术、蛋白质芯片技术，及其在肿瘤标志物的筛选和鉴定、肿瘤治疗效果的评价及肿瘤发生机制研究等方面的应用状况，并对蛋白质组学在重离子治疗中的应用进行了展望。With the accomplishment of the human genome project, proteomics becomes a new snbject on the buildup of the whole proteins and their dynamic changes in cell emerges. Cancer is a kind of complex disease involved in multi-genes and proteins. Heavy ion therapy is all arising and potential radiation treatment nowadays. This paper reviews on the main methods and technology in proteomics-- two-dimensional gel electrophoresis （2-DE）,biological mass spectrometry, protein biochips, bioinformatics and its application on identification of cancer biomarkers, evaluation of curative effect on tumour and the mechanisms of turnout formation. This paper also presents some prospects on the application of proteomics in heavv ion therapy.     

Hypernuclear Spectroscopy with Stable Heavy Ion Beams and Rare-isotope Beams:HypHI Project at GSI and FAIR

The international HypHI collaboration proposes to perform hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR in order to study neutron and proton rich hypernuclei and to measure directly hypernuclear magnetic moments for the first time.The project is divided into four phases.In the first Phase 0 experiment,the feasibility of precise hypernuclear spectroscopy with heavy ion beams will be demonstrated by observing π~- decay channels of ~e_ΛH,~4_ΛH and ~5_ΛHe with ~6Li projectiles at 2 AGeV impinging on a ~(12)C target.In the later Phases 1 through 3,studies of proton and neutron rich hypernuclei,direct measurements of hypernuclear magnetic moments and the spectroscopy of hypernuclei toward the nucleon drip-lines are planned.     

中能重离子碰撞中的同位旋效应

利用改进的量子分子动力学模型,研究了中心和擦边重离子反应中的同位旋效应.研究结果表明,在丰中子体系的中心和擦边反应中出射核子的N/Z都对对称势敏感,但对称势的密度依赖对中心和擦边反应的影响显示不同的特征.     

相对论重离子碰撞中强子气体膨胀过程的蒙特卡罗研究

利用AMPT蒙特卡罗产生器中的强子化程序模块ART1.0, 得到了强子化过程的演化图形, 并基于强子在不同时刻的空间分布图, 估算出了不同时刻的反应区域半径. 将所得结果与根据HBT关联得到的结果相比较, 定出了冻结为强子气体的时刻, 得到了合理的结果.     

重离子辐射植物的诱变效应研究及应用

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.     

原子核阻止是核子–核子碰撞截面的可能探针

利用同位旋相关的输运理论,研究了不同中子–质子比的碰撞系统在中能重离子碰撞过程中,原子核阻止的同位旋效应及其对束流能量和碰撞参数的依赖性.计算表明对于所研究的4个碰撞系统,在从费米能附近到大约150MeV/u的较宽入射能量范围内,近心碰撞的原子核阻止强烈地依赖于核子–核子碰撞截面的同位旋相关性,而对称势对它的影响并不明显.故原子核阻止是提取介质中核子–核子碰撞截面的灵敏探针.研究还表明动量相关势对原子核阻止的重要作用是不可忽略的.     

相对论重离子碰撞中的线性背景与非线性效应

系统分析了p-A,¹⁶O-A和³²S-A过程快度分布的靶核依赖性.指出:将核子-核,核-核碰撞看成核子-核子碰撞的线性叠加的几何模型只能得到靶核指数α(η) 0.4.靶核碎裂区α(η)→1的实验数据表明,目前能量下的高能重离子碰撞中,非线性效应已不可忽略.流体动力学模型计算的结果能很好地描述不同射弹过程的靶核依赖性.     

重离子碰撞中K介子和π介子产生的统一动力学模拟

用RVUU模型统一地研究了重离子碰撞中产生的K介子和π介子的动力学过程.考虑了K产生和输运过程的介质效应,同时,计入了π在核物质中的传播.用它模拟了每核子1GeV入射能量的重离子碰撞中π产生和阈下K产生过程.讨论了核介质效应对π末态性质的影响,以及对K末态性质的联带影响.计算结果表明,吸引的π光学势,影响了末态π动量分布,使横动量分布中具有小动量的π产额增大,同时明显增大了K的产额,改变了K的动量分布.这说明要合理地评价重离子碰撞的探测信息,需要统一地研究K和π的这些末态动力学作用.     

同位旋和动量依赖的相互作用在重离子碰撞中的同位旋效应

引入同位旋自由度将同位旋无关的动量相关作用改造成同位旋和动量依赖的相互作用. 利用同位旋依赖的量子分子动力学理论研究了同位旋和动量依赖的相互作用对中能重离子碰撞中动量耗散和同位旋分馏的作用. 计算结果表明动量相关作用具有重要的同位旋效应，尽管它没有明显的改变原子核阻止(动量耗散)对于两体碰撞截面和同位旋分馏强度对于对称势的灵敏依赖性，但它对于以上两种灵敏性产生了明显的减弱作用. 故动量相关作用中同位旋效应研究对于定量的研究和确定同位旋非对称核物质状态方程是重要的.     

Centrality Dependence of Charmed-Meson Photoproduction in Ultrarelativistic Heavy Ion Collisions

We calculate the centrality dependence of inclusive cross section of large-p _(T )charmed-meson(D~0,D~*,D~(*+),and D_s~+)from heavy quark fragmentation by the hard photoproduction processes in ultrarelativistic heavy ion collisions.The numerical results indicate that the contribution of the hard photoproduction processes cannot be negligible for the inclusive charmed-meson production in Au-Au collisions at Relativistic Heavy Ion Collider(RHIC)and Pb-Pb collisions at Large Hadron Collider(LHC).