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1.
The cross sections of Ni(n,x)~(58(m g))Co,Ni(n,x)~(60m)Co,Ni(n,x)~(61)Co and Ni(n,x)~(62m)Co reactions induced by neutrons around 14 MeV were measured in this work and calculated by a previously developed formula in this work.The neutron flux was determined using the monitor reaction ~(27)Al(n,α)~(24)Na and the neutron energies were measured with the method of cross-section ratios for ~(90)Zr(n,2n)~(89)Zr to ~(93)Nb(n,2n)~(92m)Nb reactions.  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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The angular distributions of the charge exchange reaction ^1H(^6He,^6Li)n were measured in reverse kinematics with a secondary ^6He beam at the energy of 4.17 A MeV.The data were analysed in the context of a microscopic calculation.It is shown that both the ground state of ^6He and the second excited state of ^6Li(3.563MeV,0^ ) have a halo structure.  相似文献   

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Ta是裂变和聚变反应堆的重要结构材料。它具有高熔点和高中子倍增率等优点。^181Ta(n,2n)^180Ta^m付反应在监测En=9~20MeV中子能谱方面具有非常大的优越性,因为它有很大的反应截面,适合测量的半衰期和平滑的激发曲线,因此对^181Ta(n,2n)^180Ta^m反应截面的准确测量有重要的应用价值。  相似文献   

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Based on the rank analysis method, algorithmization idea, and symbolic computation, in this paper we have presented a method to construct the conservation laws for nonlinear evolution equations. The polynomial conservation laws for K (n 2,n) equations and mK (m,n) equations are found by using of this approach and some new results have been obtained.  相似文献   

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Angular distributions of the ^7Li(^6Li, ^6Li)^7Li elastic scattering and the ^7Li(^6Li, ^7Lig.s.)^6Li, ^7Li(^6Li, ^7Li0.48)^6Li transfer reactions at Ec.m. = 23.7 MeV are measured with the Q3D magnetic spectrograph. The optical potential of ^6Li + ^7Li is obtained by fitting the elastic scattering differential cross sections. Based on the distorted wave Born approximation (DWBA) analysis, spectroscopic factors of ^7Li =^6Li n are determined to be 0.73 ± 0.05 and 0.90 ± 0.09 for the ground and first exited states in ^7Li, respectively. Using the spectroscopic factors, the cross sections of the ^6 Li(n, γ0,1)^7 Li direct neutron capture reactions and the astrophysical ^6Li(n, γ)^7 Li reaction rates are derived.  相似文献   

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This paper reports that the experimental excitation functions of reaction (p,n) are measured for ^106pd and ^110pd at proton energy Ep = 6.1 - 7.5 MeV and Ep = 6.0 - 7.7 MeV respectively. The off-resonance excitation functions were compared with calculation values of the statistical model. A new formula used to estimate the peak cross section of isobaric analogue resonance was tested and it was found that calculation values agree reasonably well with the present data within experimental error, which confirms that the excitation strength of isobaric analogue state in (p,n) reaction not only depends on its spin, but also proportionally increases with the projectile proton spatial transmission Tp and the spectroscopic factor S for reaction (d,p) on the same target.  相似文献   

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雷虹  方奇 《化学物理学报》1994,7(6):505-512
根据简正坐标分析的部分结果对标题配合物的实测红外和拉曼光谱进行了标识,计论了C=C,N-S伸缩振动频率随配合物氧化态变化而红移或兰移的规律及意义。  相似文献   

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The rates of the thermonuclear ^18F(P,α)^15O and ^18F(P,γ)^19Ne reactions in hot astrophysical environments are needed to understand gamma-ray emission from nova explosions. The rates for these reactions have been uncertain due to discrepancies in recent measurements, as well as to a lack of a comprehensive examination of the available structure information in the compound nucleus ^19Ne. We have examined the latest experimental measurements with radioactive and stable beams, and made estimates of the unmeasured ^19Ne nuclear level parameters, to generate new rates with uncertainties for these reactions. The rates are expressed as numerical values over the temperature range relevant for stellar explosions, as well as analytical expressions as functions of temperature in a format suitable for use in astrophysical simulations. Comparisons with the previous rate calculations are carried out, and the astrophysical implications are briefly discussed.  相似文献   

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在考虑NO分子的(5σ)^2(1π)^43P-(5σ)^2(1π)^3(2π)^2构形相互作用的情况下,对D^2Σ,C^2Ⅱ,B^2Ⅱ和L^2Ⅱ电子态的转动能级结构以及态函数进行了计算,计算结果与实验结果很相符。  相似文献   

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In this article, we assume that the (0^+,1^+) strange-bottom mesons are the conventional bs mesons, and calculate the electromagnetic coupling constants d, g1, g2, and g3 using the light-cone QGD sum rules. Then we study the radiative decays Bs0→Bs^*γ, Bs1→Bsγ, Bs1→Bs^*γ, and Bs1→Bs0γ, and observe that the widths are rather narrow. We can search for the (0^+, 1^+) strange-bottom mesons in the invariant Bsπ^0 and Bs^*π^0 mass distributions in the strong decays or in the invariant Bs^*γ, and Bsγ mass distributions in the radiative decays.  相似文献   

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用中子活化法相对于54Fe(n,P)54Mn反应,在13.50—14.80MeV中子能区测量了Ba(n,x)134Cs,134Ba(n,2n)133Ba,140Ce(n,2n)139Ce,142Ce(n,2n)141Ce和23Na(n,2n)22Na的反应截面.并将所测的结果和其他作者的结果进行了比较,中子能量是用90Zr(n,2n)89m+gZr反应和93Nb(n,2n)92mNb反应截面比法测定的。  相似文献   

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此文采用由原子轨道线性组合构成的自洽场分子轨道,用一级玻恩近似计算了能量为100-5000eV的电子与N2(^1Σ^+g、CO(^1Σ^+)弹性散射的微分截面和全截面。由于采用Gauss函数的线性组合拟合Slater函数的方法,得到了弹性散射微分截面的解析表达式,使计算大大简化,计算得到的电子和N2,CO散射的总截面和实验结果进行了比较,当入射电子的能量大于1keV时,理论值和实验值之间符合得很好  相似文献   

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用3He球形4中子探测器,通过直接反应法可以对核素的(n,2n)反应截面进行测量。在此类实验中,要求对中子束进行很好的准直。好的准直器设计要求能够提高样品处的中子注量率的均匀性,同时保证中子束流边缘处的下降幅度,能够降低低能中子所占份额。本工作采用FLUKA和MCNPX对圆柱形准直器、单锥形准直器及三种不同斜率的双锥形准直器对中子注量率的均匀性和低能中子所占份额进行了对比研究,结果表明,低斜率的双锥形准直器可以满足实验对这两方面的要求。同时,在有样品和无样品两种条件下,对探测系统经由这五种不同准直器准直后的中子束流的响应做了对比,结果显示,经过低斜率的双锥形准直器准直的中子束流,探测系统在有样品时表现为较高的计数率,在无样品时表现为较低的本底。除此之外,对准直器出口处的斜率对准直效果的影响也做了比较。最终中子准直器选用为这种低斜率的双锥形准直器,材料选用为紫铜、不锈钢、聚乙烯和铅。准直孔开口处直径为2.64 cm,长度为137 cm,经准直后样品处的中子束斑直径为3.2 cm。  相似文献   

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