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~(188)Tl的πh_(9／2)vi_(13／2)扁椭球转动带的旋称反转研究
No full text利用能量为170MeV的35Cl束流,通过157Gd(35Cl,4n)熔合蒸发反应研究了188Tl的高自旋态能级结构．依据实验结果建立了188Tl基于πh9／2(?)vi13／2组态的转动带．根据双奇Tl核能级结构的相似性,指定了188Tlπh9／2(?)vi13／2扁椭球转动带的自旋值．结果表明在188Tl中,πh9／2(?)vi13／2扁椭球转动带在低自旋区具有旋称反转性质．利用包含了质子-中子剩余相互作用的准粒子-转子模型,定性地解释了πh9／2(?)vi13／2扁椭球转动带的低自旋区旋称反转现象
重离子加速器冷却储存环监视系统的设计及其应用
No full text在兰州重离子加速器冷却储存环(HIRFL-CSR)控制系统中,需要监视现场和环境的场合很多。设计了以微处理器为核心的现场智能控制设备,阐述了系统结构、工作原理、硬件结构、软件设计,描述了监视系统的功能及实现方法。该系统具有人机交互性好、研制成本低且操作使用简便等优点,取得了良好的监视效果
Micro-PET探测器单元的研究
No full text为了发展一种快速、准确、方便、低廉的医用肿瘤诊断设备——微型正电子断层扫描仪(Micro-PET),我们对它的探测单元进行了一系列实验研究。本文描述了探测单元的结构、信号读出网络、电子学及获取系统。整个探测系统的空间位置分辨达到1.02mm。H8500光电倍增管64路阳极输出响应最大值和最小值之比为3.1,说明它的阳极输出响应具有较好的一致性
几何结构对Na_8团簇熔化过程的影响
No full text运用距离相关紧密结合的分子动力学模型,对金属原子团簇Na8的两种不同的异构体进行了数值模拟.根据零温下基态结构中不同原子到质心的不同距离,把Na8的两种异构体分为多个子系统.分别提取各个子系统在不同温度下的围绕质心的径向分布、无单位键长涨落、平均位移、扩散系数,发现尽管两个异构体的基态能量很接近,但他们的稳定性、熔化过程的热力学性质等有着很大的差别,这也反映了它们在几何结构上的差别
基于OPC技术离子源控制系统研究
No full text采用ICPDAS公司的可编程自动化控制器(PAC)Wincon8000结合稳定的I/O模块,实现基于OPC技术规范的离子源网络系统控制。研究了OPC技术在现场设备间的开放式数据交换和异构网间的数据共享,并实现大量数据源通信的标准机制
~(176,178)Os新低位激发态的识别
No full text利用在束实验产生具有β+/EC衰变性质核素176,178Ir,分析了在束实验条件下获得的γ-γ符合数据,识别出了176Os的4条新能级和13条新γ跃迁、178Os的5条新能级和14条新γ跃迁。籍助氦喷嘴快速带传输系统,进一步对176Ir的β+/EC衰变进行了测量,在确认在束测量新γ射线的同时建议了176Ir的一个低自旋同核异能态。通过两准粒子耦合的半经验计算,建议了176,178Ir基态及同核异能态的组态
单粒子在非轴对称八极形变势场中的混沌运动
No full text针对单粒子处在长椭球谐振子势加上Y32+Y3-2形变势场中的情况,从经典和量子两个角度分析了粒子在非轴对称八极形变势场中的混沌运动．通过经典的轨道稳定性分析,指出了系统等势能面性质对粒子运动特点的重要性．又通过对体系存在的能级免交叉现象,三维不对称谐振子相干态在势场中的演化特征的研究,具体地说明了八级形变势的非轴对称性使单粒子更容易出现混沌运动
Impacts of the embedded windings to the field quality of dipole
No full textCooler Storage Ring (CSR) of Heavy Ion Research Facility in Lanzhou (HIRFL) consists of a main ring (CSRm) and an experimental ring (CSRe). Two particular C-type dipoles with embedded windings are used in the injection beam line of CSRm. They also act as the prototype dipoles of CSRe. The windings are designed to improve the field quality by their trimming current. The current impacts on field homogeneity and multipole components are investigated by a hall sensor and a long coil, respectively. The experiment shows that a field homogeneity of +/- 1.0 x 10(-3) can be reached by adjusting the trimming currents, though the multipole components change correspondingly. In our case, the quadrupole component is decreased to a low level with the octupole, decapole and 12-pole ones increased slightly when the trimming current is optimized
Constrain intergalactic medium from the SZ effect map
No full textIn this paper, we try to detect the SZ effect in the 2MASS DWT clusters and less bound objects in order to constrain the warm-hot intergalactic medium distribution on large scales by cross-correlation analysis. The results of both observed WMAP and mock SZ effect map indicate that the hot gas distributes from inside as well as outside of the high density regions of galaxy clusters, which is consistent with the results of both observation and hydro simulation. Therefore, the DWT measurement of the cross-correlation would be a powerful tool to probe the missing of baryons in the universe
Double neutron/proton ratio of nucleon emissions in isotopic reaction systems as a robust probe of nuclear symmetry energy
No full textThe double neutron/proton ratio of nucleon emissions taken from two reaction systems using four isotopes of the same element, namely, the neutron/proton ratio in the neutron-rich system over that in the more symmetric system, has the advantage of reducing systematically the influence of the Coulomb force and the normally poor efficiencies of detecting low energy neutrons. The double ratio thus suffers less systematic errors. Within the IBUU04 transport model the double neutron/proton ratio is shown to have about the same sensitivity to the density dependence of nuclear symmetry energy as the single neutron/proton ratio in the neutron-rich system involved. The double neutron/proton ratio is therefore more useful for further constraining the symmetry energy of neutron-rich matter