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将HI-13北京串列加速器次级束流线产生的放射性核素 7Be分别注入到天然Pt和Al中, 利用两个高纯锗探测器同时测量 7Be 经由7Li第一激发态衰变后跃迁到基态产生的478 keVγ射线产额随时间的变化, 结果在实验误差范围内(<0.14%)没有发现7Be衰变率在Pt与Al中有明显差别, 讨论了这两种材料的电子亲和势及有效电子密度与EC衰变率的关系。 We measured the variation of the decay rate of 7Be implanted in Pt and Al host materials by detecting the 478 keV γ ray emitted from the first excited state of 7Li which is produced by EC decay of 7Be with two HPGe detectors simultaneously, and found no difference of 7Be decay rate in Pt from that in Al within our experimental error (<0.14%). We discussed the relation of the decay rate variation with the electronic affinities and effective electron densities near the implanted ions in the two different host materials. 相似文献
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Online The decay rate variation of r Be implanted into platinum and aluminum host materials has been measured via detecting the 478 keV γ-rays from the first excited state of r Li populated in the electron capture decay of7r Be. The result (λpt - λA1)λ0 = (-0.17 ± 0.13)% is obtained. It is smaller than the theoretical estimate from the TB-LMTO calculation (0.38%). This is quite different from our previous study which showed a 1arger decay rate variation ((0.8 ± 0.2)%) than the TB-LMTO calculation (0.30%) of 7 Be in palladium and gold. It is suggested that the effective quasi-free electron density near the implanted ions in different metal host materials may play an important role in r Be EC decay rate variation in addition to the electronic affinity and crystal structure of different host materials. 相似文献
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在0—67kbar压力范围,对名义成分为Nb3(Al1-xGex)的合金(x=0.20,O.23,0.25;含有Al5+σ相)进行了热处理。X射线分析表明:1)随着压力的升高,Al5相的晶胞参数a0出现极大值;2)与Al5相结构成分密切相关的衍射峰(211),(210)的相对累积强度I211/I210随压力的变化与a0的变化类似;3)Al5相结构成分随压力向着富Nb的方向移动。低温测试结果表明:随着压力的升高,试样的超导转变温度降低,转变宽度出现极大值。
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