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71.
72.
设计了一种利用声强衰减规律进行三维声源定位的实验方法,声源定位主要通过测量声源相对探源中心的距离、方向和高度实现.利用声强比呈对数衰减的原理,推导了声波强度在空气中的衰减规律与声源距离的关系式;设计了一种角位移法测量声源方向,并给出了角位移大小与声强比到达峰值时的时间之间的关系式;通过电控升降平台,测定了声源到参考平台水平面的高度.并制作了在1立方米范围内的三维声源定位实验装置,实验结果表明,本实验装置在二维平面内,声源距离测量的最大相对误差为2.3%,方位角测量的最大误差为1.6°;在三维空间内,声源距离测量的最大相对误差为2.9%,高度测量的最大相对误差为4.9%,方位角测量的最大误差为0.8°,通过实验证明了本实验系统定位效果较好. 相似文献
73.
中微子可能的马约拉纳粒子属性超出了目前标准模型的范畴,是粒子物理与核物理研究领域最重要的科学问题之一。无中微子双贝塔衰变(0vββ)实验是能够确定中微子马约拉纳属性的唯一途径。0vββ的发现可以揭示中微子绝对质量、轻子数破缺、物质—反物质不对称等一系列自然奥秘,是当今粒子物理与核物理研究的前沿课题。在探索无中微子双贝塔衰变的可选择实验方案中,低温晶体量热器具有高能量分辨率、高运行稳定性和低辐射本底的技术优势,成为新一代0vββ实验最具竞争力的探测器技术之一。文章首先介绍无中微子双贝塔衰变的研究历史,之后介绍低温晶体量热器及其最先进的代表——CUORE实验,最后展望关于我国锦屏地下实验室开展低温晶体量热器0vββ实验研究的前景。 相似文献
74.
We present a systematic analysis of two-pion interferometry for the central Au+Au collisions at √SNN=3, 5, 7, 11, 17, 27, 39, 62, 130 and 200 GeV/c with the help of a multiphase transport (AMPT) model. Emission source-size radius parameters Rlong, Rout, Rside and the chaotic parameter A are extracted and compared with the experimental data. Transverse momentum and azimuthal angle dependencies of the HBT radii are also discussed for central Au+Au collisions at 200 GeV/c. The results show that the HBT radii in central collisions do not change much above 7 GeV/c. For central collisions at 200 GeV/c, the radii decrease with the increasing of transverse momentum PT but are not sensitive to the azimuthal angle. These results provide a theoretical reference for the energy scan program of the RHIC-STAR experiment. 相似文献
76.
Some experimental techniques and theoretical analysis on unbound nuclei structure study are briefly introduced in this article. The unbound nuclei structure investigation can inspect the reliability of theoretical calculation, and is also important to extend the modern nuclear structure model to exotic nuclear regions. With the recent development of radioactive Ion Beam (RIB) facility and some new experimental methods, the structure of unbound nuclei near drip line can be studied in experiment. 相似文献
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78.
Based on the facility of the Shanghai Laser Electron Gamma Source (SLEGS), the transmutation for nuclear wastes such as 137Cs and 129I is investigated. It is found that nuclear waste can be transmuted efficiently via photonuclear reaction triggered by gamma photons generated from Compton backscattering between CO2 laser photons and 3.5 GeV electrons. The nuclear activities of 137Cs and 129I are evaluated and compared with the results of transmutation triggered by bremsstrahlung gamma photons driven by ultra intense laser. Due to the better character of gamma photon spectrum as well as the high brightness of gamma photons, the transmutation rate of Compton backscattering method is much higher than that of the bremsstrahlung method. 相似文献
79.
80.
Using an isospin-dependent quantum molecular dynamics (IQMD) model, we study the 15C induced reactions from 30-120 MeV/nucleon systematically. Here the valence neutron of 15C is assigned at both 1d5/2 and 2s1/2 states respectively in order to study the density effect of reaction mechanism. It is believed that the existent neutron halo structure at the 2s1/2 state of 15C will affect the light particle emission evidently. In our calculation, the different density distributions of 15C at two states are calculated by relativistic mean field (RMF) model and introduced in the initiation of IQMD model, respectively. It is found that some observables such as emission fragmentation multiplicity, emission neutron/proton ratio and emission neutrons’ kinetic energy spectrum are sensitive to the initial density distribution. 相似文献