983 resultados para 367.224


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针对兰州重离子加速器冷却储存环的流强设计 ,对其空间电荷效应进行了讨论 .随着流强增高和发射度降低 ,束流自作用场效应 (空间电荷效应 )逐渐显现 .散焦的空间电荷力造成的粒子自由振荡频移和束流包络增长 ,带来了不稳定因素 ,这些不稳定因素就限定了储存环的流强极限

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介绍了 HIRFL (兰州重离子研究装置 )上利用荧光靶对束团截面形状和流强大小的实时测量方法和对光斑图像进行动态分析的硬件结构以及软件的设计方法 ,并定量地给出一些测量结果。该系统具有可靠性好、精度高、测量直观、应用软件的界面友好等优点

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介绍了兰州重离子加速器冷却储存环 (HIRFL CSRm)中束流位置测量系统设计的基本原理、PICKUP探针参数的选择以及有关物理量的计算。并完成了桌上实验 ,得出了有关结论。

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The RFQ cooler and buncher RFQ1L is a key device of the SHANS (Spectrometer for Heavy Atoms and Nucleax Structure). The status of the machining and assembly of the central part is introduced, and the structure of the whole RFQ1L system and the preliminary plan for the testing are discussed also.

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The Isochronous Mass Spectrometry is a high accurate mass spectrometer. A secondary electrons time detector has been developed and used for mass measurements. Secondary electrons from a thin carbon foil are accelerated by ail electric field and deflected 180 degrees by a magnetic field onto a micro-channel plate. The time detector has been tested with alpha particles and a time resolution of 197 ps (FWHM) was obtained in the laboratory. A mass resolution around 8 x 10(-6) For Delta m/m was achieved by using this time detector in a pilot mass measurement experiment.

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本论文分为两部分,分别沿自旋和同位旋自由度开展研究工作。第一部分介绍原子核高自旋态研究的相关背景知识、基础理论等,描述在束γ谱学研究的实验技术和方法,分析和讨论形变核179Pt转动带能级结构的特性,并采用相关理论对其进行分析。通过融合蒸发反应149sm(35cl,P4n)布居奇A核179Pt的高自旋激发态。指认179Pt的组态为1/2-[521],5/2-[512〕和7/2+〔633〕的三条转动带。在hco=0.27 Mev附近,观测到1/2-〔521]带内顺排角动量突然增大,建议该现象是由一对113/2中子发生顺排造成的。另外观察到在7/2+〔633]带中出现较大的旋称劈裂。建议由于三轴形变加强了波函数中来自几=1/2轨道的组分,从而导致较大的旋称劈裂的出现。论文第二部分介绍重丰中子核衰变性质研究以及新核素合成、鉴别工作的相关背景知识、理论基础及实验技术。并对相关的研究工作分别进行阐述。通过快中子反应合成并鉴别了新核素19705和新的同核异能素186rnTa,利用γ(x)谱学方法首次建立了19705的部分衰变纲图。测得它们的半衰期分别为2.8士0.6 min和1.50.1 min,并与理论计算结果进行了比较;进行了原子核基态β延发裂变(pDF)的实验研究,经测量首次发现了230Ac的两个pDF事件,测得23OAc的pDF几率为(1.19±0.40)

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The catalytic properties of the passivated, reduced passivated, and fresh bulk molybdenum nitride for hydrazine decomposition were evaluated in a microreactor. The reaction route of hydrazine decomposition over molybdenum nitride catalysts seems to be the same as that of Ir/gamma-Al2O3 catalysts. Below 673 K, the hydrazine decomposes into N-2 and NH3. Above 673 K, the hydrazine decomposes into N-2 and NH3 first, and then the produced NH3 further dissociates into N-2 and H-2. From the in situ FT-IR spectroscopy, hydrazine is adsorbed and decomposes mainly on the Mo site of the Mo2N/gamma-Al2O3 catalyst. (C) 2004 Elsevier Inc. All rights reserved.

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采用生长速率法和孢子萌发法分别测定了阿魏不同溶剂(石油醚、氯仿、乙酸乙酯、无水乙醇)提取物对玉米弯孢霉叶斑病菌菌丝生长和孢子萌发的抑制作用,利用荧光显微镜观察了提取物对孢子萌发的影响。结果表明,阿魏提取物对玉米弯孢霉叶斑病菌的抑菌作用主要表现在对菌丝生长的抑制,抑菌效果随提取物浓度的增大而提高;无水乙醇提取物对菌丝生长的抑制效果最好,EC50为326.46mg/L,其次是氯仿提取物,EC50为574.88mg/L,乙酸乙酯和石油醚的提取物抑菌效果较差,EC50均超过了1000mg/L。