用1-苯基-3-甲基-4-苯甲酰基-5-吡唑啉酮萃取~(46)Sc的研究

用1-苯基-3-甲基-4-苯甲酰基-5-吡唑啉酮(PMBP)做萃取剂,氯仿和环己烷为稀释剂,观察了在HCl溶液46Sc的溶剂萃取行为。实验结果表明,从10-3~10-2mol/L的HCl溶液中用PMBP-氯仿(或环己烷)能有效地萃取46Sc,萃取率可达95%以上。另外,对PMBP从HCl溶液中萃取46Sc和234Th的结果也做了比较,结果表明,通过控制水溶液中HCl的浓度,能实现234Th与46Sc的分离。

IMP质子治癌3D剂量探测系统

文章描述了中国科学院近代物理研究所(IMP)正在研制的IMP质子治癌装置3D剂量测量系统。该系统主要由2D剖面探测器、辐照深度和剂量探测器、射程调整器等组成。其中,多级双维位置灵敏平行板雪崩探测器(MPPAC)使用C3F8作为工作气体,工作气压为700Pa,阳极电压为+700V。对3组分α粒子测得位置分辨为0.54mm(FWHM)。

Tectonic uplift in the northern Tibetan Plateau since 13.7 Ma ago inferred from molasse deposits along the Altyn Tagh Fault

IEECAS SKLLQG

黄土高原植物与不同粒级中土壤体系氮同位素组成变化及意义

IEECAS SKLLQG

35MeV/uAr离子辐照聚酯膜引起的效应研究

采用多种手段研究了 35Me V/u的 Ar离子辐照聚酯 (PET)膜产生的微观结构变化 .结果表明 ,辐照使聚酯的化学键断裂并产生了炔端不饱和基团和自由基 .断键主要发生在乙二醇残留物、苯环的对位和酯的 C— O键上 .随着吸收剂量的增加 ,材料的结晶度逐渐降低 ,由原始的41 .7%减至最高辐照量时的 1 5.0 % .研究发现 ,聚脂的非晶化转变截面与电子能损呈线性关系 ;断键和非晶化效应主要取决于样品的吸收剂量 ,并存在一个约 4.0 MGy的阈值

网络型油田通用数据获取与处理系统

介绍了一种利用现代计算机网络技术进行网络通信、利用现代计算机技术进行数据采集与处理的系统。它为油田的生产计量而设计 ,同时适应于大多数的工业现场监测。文中主要介绍了该系统的结构、相应的软硬件技术。该系统已投入使用 ,效果良好。

An outlook of heavy ion driven plasma research at IMP-Lanzhou

Since the successful completion of the cooling storage ring (CSR) project in China at the end of 2007, high qualitative heavy ion beams with energy ranging from keV to GeV/u have been available at the Heavy Ion Research Facility at Lanzhou (HIRFL). More than 10(9) 1 GeVlu C6+ particles or 10(8) 235 MeV/u Xe particles can be stored in the CSR main-ring and extracted within hundred nano-seconds during the test running, the beam parameters will be improved in the coming years so that high energy density (HED) conditions could be achieved and investigated there. Recent scientific results from the experiments relevant to plasma research on HIRFL are summarized. Dense plasma research with intense heavy ion beams of CSR is proposed here.

Biodosimetry estimate for high-LET irradiation

The purpose of this paper is to prepare for an easy and reliable biodosimeter protocol for radiation accidents involving high-linear energy transfer (LET) exposure. Human peripheral blood lymphocytes were irradiated using carbon ions (LET: 34.6 keV mu m(-1)), and the chromosome aberrations induced were analyzed using both a conventional colcemid block method and a calyculin A induced premature chromosome condensation (PCC) method. At a lower dose range (0-4 Gy), the measured dicentric (dics) and centric ring chromosomes (cRings) provided reasonable dose information. At higher doses (8 Gy), however, the frequency of dics and cRings was not suitable for dose estimation. Instead, we found that the number of Giemsa-stained drug-induced G2 prematurely condensed chromosomes (G2-PCC) can be used for dose estimation, since the total chromosome number (including fragments) was linearly correlated with radiation dose (r = 0.99). The ratio of the longest and the shortest chromosome length of the drug-induced G2-PCCs increased with radiation dose in a linear-quadratic manner (r = 0.96), which indicates that this ratio can also be used to estimate radiation doses. Obviously, it is easier to establish the dose response curve using the PCC technique than using the conventional metaphase chromosome method. It is assumed that combining the ratio of the longest and the shortest chromosome length with analysis of the total chromosome number might be a valuable tool for rapid and precise dose estimation for victims of radiation accidents.

OVERVIEW ON THE HIRFL-CSR FACILITY

The status of the HIRFL (Heavy Ion Facility in Lanzhou) - Cooler Storage Ring (CSR) at the IMP is reported. The main physics goals at the HIRFL-CSR are the researches on nuclear structure and decay property, EOS of nuclear matter, hadron physics, highly charged atomic physics, high energy density physics, nuclear astrophysics, and applications for cancer therapy, space industries, materials and biology sciences. The HIRFL-CSR is the first ion cooler-storage-ring system in China, which consists of a main ring (CSRm), an experimental ring (CSRe) and a radioactive beamline (RIBLL2). The two existing cyclotrons SFC (K=70) and SSC (K=450) are used as its injectors. The 7MeV/u12C6+ ions were stored successfully in CSRm with the stripping injection in January 2006. After that, realized were the accelerations of C-12(6+), Ar-36(18+), Kr-78(28+) and Xe-129(27+) ions with energies of 1GeV/u, 1GeV/u, 450 MeV/u and 235 MeV/u, respectively, including accumulation, electron cooling and acceleration. In 2008, the first two isochronous mass measurement experiments with the primary beams of Ar-36(18+) and Kr-78(28+) were performed at CSRe with the Delta p/p similar to 10(-5).

Cytogenetic Effects of Low Doses of Energetic Carbon Ions on Rice After Exposures of Dry Seeds, Wet Seeds and Seedlings

In order to investigate the biological effects of heavy ion radiation at low closes and the different radiosensitivities of growing and non-growing plants. rice at different lift stages (dry seed, wet seed and seedling) were exposed to carbon ions at closes of 0 02, 0.2, 2 and 20 Gy. Radiobiological effects on survival, root growth and mitotic activity, as well as the induction of chromosome aberrations in root meristem. were observed The results show that radiation exposure induces a stimulatory response at lower close and an inhibitory response at higher dose on the mitotic activity of wet seeds and seedlings Cytogenetic damages are induced in both seeds and seedlings by carbon ion radiation at doses as low as 0.02 Gy Compared with seedlings. seeds are more resistant to the lethal damage and the growth rate damage by high doses of carbon ions, but are more sensitive to cytogenetic damage by low closes of irradiation Different types of radiation induced chromosome aberrations are observed between seeds and seedlings. Based on these results, the relationships between low close heavy ion-induced biological effects and the biological materials are discussed.

Nucleon Superfluidity in Asymmetric Nuclear Matter and Neutron Star Matter

We have investigate the nucleon superfluidity in asymmetric nuclear matter and neutron star matter by using the Brueckner-Hartree-Fock approach and the BCS theory. We have predicted the isospin-asymmetry dependence of the nucleon superfluidity in asymmetric nuclear matter and discussed particularly the effect of microscopic three-body forces. It has been shown that the three-body force leads to a strong suppression of the proton S-1(0) superfluidity in beta -stable neutron star matter. Whereas the microscopic three-body force is found to enhance remarkably the (PF2)-P-3 neutron superfluidity in neutron star matter and neutron stars.

超铀核的研究

本文详细调研了超铀核研究的发展过程，总结了超铀区核素产生方法、传输方法以及分离方法。结合我国的实际，利用中国科学院高能物理研究所的质子直线加速器的质子束，轰击稀有放射性靶，通过(p，4n)反应道合成和研究了超铀区新核素~(235)Am，巧妙地利用X射线对核素进行了指定，得到了它的半衰期及合成截面，实验中没有观测到伴随~(235)Am的β~+(EC)衰变的γ跃迁，该方法发表后即被日本的实验小组采用；同时利用中国科学院近代物理研究所的SFC加速器提供的~(20)Ne束流轰击~(233)U靶，测量反应产物的α衰变，第一次观测到~(250)102的α衰变，由此得到了~(250)102的半衰期，它不同于~(250)102已知的半衰期；在实验中还观测到一个能量为17.6MeV的衰变。实验采用氦喷嘴传输技术对反应产物进行传输，并根据产物的不同衰变采用了不同的测量方法，对~(235)Am由于其半衰期长，采用了化学分离的分离方法并测量X、γ及其符合测量，而对~(250)102等采用直接测量其α衰变，利用衰变关系进行鉴别的方法。通过对实验的总结分析了利用现有条件研究更重核素的可能。

钠原子团簇性质的理论研究

本论文介绍了近五年来，对钠原子团簇的理论研究中所取得的一些有意义的结果，以及在碳团簇研究方面的初步进展。在电子基态条件下，利用距离相关的紧束缚的分子动力学模型(DDTB—MD)系统研究了钠原子团簇Na_n的结构、振动、热力学、碰撞动力学等方面的特性。在团簇Na_２、Na_3、Na_4、Na_5的结构和振动研究中，发现在低温时，钠原子团簇象刚性分子一样，会呈现出固有的振动本征谱，振动谱与原子团簇的结构密切相关，不同的异构体的振动谱可以有很大的差别，通过某一团簇的振动本征谱能够重建团簇的几何形状，可作为实验上决定原子团簇结构的探针。在实验上测量的原子团簇并非都是冷的，有时原子团簇会热到足以熔化。在对原子团簇Na_4、Na_8、Na_(20)这些有限多体在有限温度下的相变研究中，发现在钠原子团簇中普遍存在着类固-类液相变现象。在O-400 K温区系统研究了Na_4的异构化，发现当T≥100 K时，存在C_(3v)和D_(2h)两种异构体之间的转变。同时，发现当T>200 K时，D_(2h)结构的Na_4出现一种新的运动模式-赝转动。赝转动前后，分子的结构不变，只是宏观取向发生改变。通过跟踪体系势能的变化，提取出赝转动势垒为O．023 eV。对第一个满壳(Na_8)附近Na_7+Na_7、Na_8+Na_8及Na_9+Na_9体系的团簇碰撞动力学性质进行了系统性研究，深入理解团簇之间的非区域力和多种运动的耗散效应，提取了双团簇分子(Na_9)_2的特征振动频率24 cm~(-1)。利用目前计算机模拟实验中最先进最重要的第一性原理分子动力学方法(FHl96MD)优化了Na_2的键长5.789 Bohr，模拟了Na_2的分子动力学，提取了Na_2振动频率235 cm~(-1)。并在FHI96MD的基础上，发展了一个在离子基态条件(冻结离子运动)下，描述复杂凝聚态体系的电子动力学的时间相关的局域密度近似(TDLDA)模型。这个模型被成功地应用于Na_2价电子对高强度超短脉冲激光的响应、强激光场中团簇Na_2的谐波产生的研究。在电子基态条件下，发展了一个经典分子动力学模型(CMD)用于研究碳富勒烯、纳米碳管的结构、热力学性质。研究了纳米碳管中封装C_(60)链的形成。关键词：紧束缚分子动力学，时间相关的局域密度近似，钠团簇，碳纳米管