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<正>导论将量子计算的想法变成实用的技术是当前科技领域的一大挑战,利用变化的电磁场来操控硅晶体管中的电子,是一个较为可能的实施方法。在本题中,我们尝试利用射频反射法和单电子晶体管(以下简称SET)从硅基量子计算原型机读出量子比特。本文第一部分与第二部分讨论无线电波在电缆中的传输,第三部分探究了无线电波的反射条件,第四部分介绍了SET,第五部分与第六部分介绍了射频反射技术以及优化方法。 相似文献
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原计划于2020年7月在立陶宛举办的第51届国际物理奥林匹克竞赛IPhO (International PhysicsOlympiad)受新冠疫情的影响未能如期举行。经过国际物理奥委会同意,俄罗斯发起并举办了2020年国际物理奥林匹克竞赛的命题和组织工作,称为IdPhO (International distributed Physics Olympiad)。此次竞赛采用线上考试的形式,跨越了14个时区,俄罗斯的组织者和命题者为此做出了很大努力。官方网站可见: https://i20.mipt.ru。 相似文献
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Based on the angular distribution of the ^8Li(d, n)^9Beg.s, reaction at Ec.m. = 8.0 MeV and distorted wave Born approximation analysis, the single particle spectroscopic factor S1,3/2 for the ground state of ^9Be = ^8Li×p is derived to be 0.64 ± 0.21. In addition, we deduce the astrophysical S-factors and rates of the ^8Li(p, γ)^9Beg.s. direct capture reaction at energies of astrophysical interests. 相似文献
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The cross sections for ~(59,60)Ca, recently measured in the 345 A MeV ~(70)Zn+~9 Be reaction,were estimated using the FRACS parametrization and an empirical formula,which are in good agreement.The FRACS parametrization and the empirical formula are combined to predict the cross sections for extreme calcium isotopes ~(66,70)Ca in the~(70,80)Zn+~9 Be reactions at the incident energies of ~(60,80),and 345 A MeV.The dependence of emperical formula parameters on the reaction system,as well as the incident energy,are discussed.The results indicate that ~(66,70)Ca can be discovered in reactions of ~(60,80)A MeV ~(80)Zn+~9 Be.The predicted binding energy for extreme neutron-rich isotopes by the spherical relativistic continuum Hartree-Bogoliubov theory was adopted in the calculation.Hence,the planned Beijing Isotope-Separation-On Line Neutron-Rich Beam Facility(BISOL),which is a third generation radioactive ion beam facility,could provide the opportunity to discover ~(66,70) Ca and neighboring neutron-drip line nuclei. 相似文献
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李志宏 李云居 苏俊 张昊 谌阳平 颜胜权 王友宝 郭冰 连钢 曾晟 贺国珠 张奇玮 张龙 曹富强 李鑫悦 马田丽 南丁 崔宝群 陈立华 柳卫平 《原子核物理评论》2020,37(4):816-824
长寿命放射性核素26Al是星际介质、$\gamma$ 射线天文学和太阳系形成研究中最重要的核素之一。最可能合成26Al的三种天体场所都与25Mg(${\rm p},\,{\rm{\gamma }}$ )26Al反应相关,因此精确测量其近阈能级的共振强度和天体物理反应率对人们认识宇宙26Al的来源具有重要意义。本文回顾了25Mg(${\rm p},\,{\rm{\gamma }}$ )26Al反应的实验研究方法和最新研究进展,特别是介绍了我国对该反应的间接测量实验以及直接实验测量计划。当前的间接测量结果提升了25Mg(${\rm p},\,{\rm{\gamma }}$ )26Al天体物理反应率的精度,也可以帮助我们估算直接测量的产额,并优化深地直接测量的实验设计。高能点的直接测量结果与国际上其它实验结果在误差范围内符合很好,表明本项目研制的探测装置工作状态良好,能够胜任锦屏深地核天体物理实验研究。 相似文献
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天体物理感兴趣能区(伽莫夫窗口)的带电粒子核反应截面极小,在地面进行测量会受到宇宙射线诱发本底的严重干扰.进行地下实验室核反应测量成为解决这一问题的主要途径.锦屏深地核天体物理实验(JUNA)装置是我国首个地下核天体反应测量设施,为开展恒星核合成关键反应直接测量提供了绝佳机遇.本工作测量了锗酸铋(BGO)探测阵列和溴化镧(LaBr3)探测器在JUNA装置上的γ本底能谱,并通过减小符合时间、点火数选择、粒子甄别等技术,进一步压低了5~10 MeV能区的γ本底,同时讨论了探测器本底对部分JUNA计划开展的核天体反应测量的影响. 相似文献
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The angular distribution of the ^2H(^8Li, ^9Be)n (ground state) reaction, important to primordial nucleosynthesis in the inhomogeneous model, has been measured at E = 8.1 MeV using a secondary ^8Li beam. Cross section of this reaction was determined to be 9.0 4±3.4 mb. According to the cross section, the astrophysical S-factor was calculated to be 272 4±103 keV b. It is shown that ^2H(8^Li, ^9Be)n (ground state) reaction is important for creating 9Be, but less important for destroying aLl in primordial nucleosynthesis. 相似文献
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王友宝 苏俊 韩治宇 唐兵 崔保群 葛涛 吕银龙 陈志强 郭冰 李鑫悦 李云居 李志宏 连钢 马田丽 马鹰俊 谌阳平 苏毅 王春光 吴弘毅 颜胜权 曾晟 郑云 周超 党永乐 付光永 何阳帆 刘伏龙 吴笛 张天爵 柳卫平 BRIF合作组 《原子核物理评论》2018,35(4):445-449
北京放射性离子束装置(Beijing Radioactive Ion-beam Facility,BRIF)是基于在线同位素分离器技术的国家大科学平台。在BRIF装置上利用100 MeV的质子束轰击较厚的反应靶产生放射性核素;反应产物经离子源电离和在线分离,在线同位素分离段可引出100~300 keV的放射性核束,质量分辨率达20 000。在基金委科学仪器基础研究专项的支持下,建成了多用途的衰变实验终端,包括束流传输管道、通用靶室、带电粒子和γ探测器、集成电子学和数据获取系统等。利用100 MeV的质子束轰击MgO厚靶产生了流强高达1×105 pps的20Na放射性核束。通过高效率地同时测量β,γ和α,第一次直接观测到20Na非常稀有的β-γ-α衰变模式。Beijing Radioactive Ion-beam Facility(BRIF) has been commissioned as the national Radioactive Ion Beam(RIB) facility based on the Isotope Separator On Line(ISOL) technique since 2016. At BRIF, the radioactive nuclides are produced by the proton beam of 100 MeV bombarding a thick-target, the reaction products diffusing out of the target are ionized by an ion source and delivered to the online mass separator. In addition to the post-accelerated radioactive ion beams, BRIF can provide low-energy ISOL beams of 100 to 300 keV with a mass resolution of 20 000. A general-purpose decay station has been built including the ISOL beam transport line, a conventional reaction chamber, charge-particle and γ detectors with integrated electronics and data acquisition system. An intense 20Na ISOL beam up to 1×105 pps was produced by using the 100 MeV proton beam bombarding a MgO thick target. With high-efficiency measurements of β, γ and α simultaneously, very rare β-γ-α decay mode in 20Na has been directly observed for the first time in the present work. 相似文献