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简单地介绍了远离β-稳定线重质量丰中子核的合成和研究的科学意义,报告了元素指定对远离β-稳定线重丰中子核研究的重要作用.The significance of the synthesis and study of heavy neutron-rich nuclides far from β-stability is briefly introduced. The important role of element assignment for studying heavy neutron-rich nuclides far from β-stability is reported. 相似文献
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The basic process of an exotic decay mode namely β-delayed fission is simply introduced. The progress status of the study in the world is essentialized. The observation of β-delayed fission of 228Ac is reported. The radium was radiochemically separated from natural thorium. Thin Ra sources in which 228Ac was got through 228Ra →β-228Ac were prepared for observing fission fragments from β-delayed fission of 228Ac. They exposed to the mica fission track detectors, and measured by an HPGe γ-ray detector. The β-delayed fission events of 228Ac were observed and its β-delayed fission probability was found to be (5±2)×10-12. 相似文献
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189W activities were produced via the 192Os(n, α) reaction using irradiation of isotopically enriched 192Os metallic powder of ~100 mg/cm2 with 14 MeV neutrons. The X-γ and γ-γ coincidence measurements were made so as to obtain γ rays from 189W decay and its coincidence relations. A new simple decay scheme of 189W including three γ rays of 210.2, 229.6 and 260.2 keV is proposed. Two new levels of 189Re at 470.4 and 489.8 keV are assigned. 相似文献
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含有异喹啉骨架的化合物是一类很重要的含氮杂环化合物,广泛存在于具有生物活性的天然产物、有机材料、以及药物分子中。传统的合成异喹啉的方法需要苛刻的反应条件,因此使用温和,简单的方法构建这一骨架的化合物具有重要的现实意义。银类化合物具有路易斯酸特性能够催化活化三键,利用这一特点并使用含氮的亲核试剂进行分子内亲核加成活化的三键是合成异喹啉衍生物的重要方法。本文主要综述了以2-炔基苄亚胺、2-炔基苄基叠氮、2-炔基苯甲醛肟、2-炔基苯甲醛腙及其(2-(乙炔基)芳基)-1,2,3-三唑为反应物,在银催化条件下构建异喹啉环的研究进展,并对部分反应的机理进行了讨论。 相似文献
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通过60MeV/u18O离子照射天然铀靶产生Ba放射性同位素,使用BaCl2沉淀法从大量铀和其它反应产物混合物中分离出Ba.通过离线γ谱学方法测量了Ba样品的γ射线单谱,根据Ba同位素特征γ射线峰的强度及其它相关数据计算了Ba同位素的生成截面.发现在厚铀靶的情况下,缺中子Ba同位素仍有较高的截面. The radioactive Ba isotopes were produced by 60 MeV/u~(18)O ion bombardment of natural uranium. Ba was separated from U and the reaction product mixture by BaCl_(2) precipitation. The Ba fraction was measured by off-line γ-ray spectroscopy. The cross sections of the individual Ba isotope were calculation based on the intensities of the character γ-ray peaks of Ba isotopes and other relative information. It was found that the n-deficient Ba isotopes have higher cross sections using the thick uranium targets. 相似文献
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为了研究不同的酰胺夹醚化合物对萃取镧的性能,本文使用N,N′-二甲基-N,N′-二辛基-4-氧庚二酰胺(DMDOOHA)为萃取剂,以1-甲基-3-丁基咪唑六氟磷酸盐离子液体([C4mim+][PF6-])为稀释剂,研究其在水相中萃取La3+的行为,考察了萃取时间,pH,萃取剂的的浓度、及温度对萃取分配比的影响。实验表明,萃取剂在离子液体[C4mim+][PF6-]中对La3+的具有强烈的萃取能力。机理研究表明,在([C4mim+][PF6-]体系中,萃取剂与La3+可能形成3∶1配合物。萃取过程为热力学自发的过程。 相似文献
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