共查询到20条相似文献,搜索用时 78 毫秒
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泊肃叶公式的椭圆修正史彭,闫增锋(西安建筑科技大学物理实验教研室710055)物理实验和流体力学实验中,一般用毛细管法测定液体、气体的粘滞度.一般认为毛细管内截面是圆形,按泊肃叶公式计算待测流体的粘滞度.而实用的毛细管内截面并非是严格的圆形,或多或少... 相似文献
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根据泊肃叶公式的积分形式,得到了泊肃叶公式的求和形式,从而导出了液体粘度的理论修正公式,比较了理论修正公式与经验修正公式,并提出了小球半径与管半径之比的合理取值。 相似文献
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王新强 《原子与分子物理学报》1994,(3)
对Schlosser等人提出的,基于考虑了离子间电荷转移的相互作用势的晶体结合能的普适表达式中的待定参数,以15种NalCl结构的碱卤离子晶体为对象,全部进行了重新确定,同时,指出了原文[Phys.Rev..B44(1991),9696和Phys.RevB47(1993),1073]中在确定参数时存在的问题。从得到的结合能曲线出发计算出的等温压缩曲线与实验数据都作过了比较。 相似文献
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在不同能量下, 利用核束缚能对虚光子四动量的平方项进行修正, 分别计算了Sn核碰撞中核束缚能对反应截面中湮灭项和康普顿散射项及K因子的影响。 结果表明, 核束缚能在小x区域对反应截面中湮灭项和康普顿散射项及K因子的影响明显, 并且能量越低这种影响越显著, 随着x2增大影响逐渐消失。 We made a revision of square of virtual photon four momentum by means of using nuclear bin ding energy formula in different energy, and we also made an accurate calculation for the effect of nuclear binding energy on K factor and Compton term and annihilate term in the Drell Yan process of the Sn Sn collision. The outcome indicates that the effect of nuclear binding energy on the annihilate term and the Compton term is marked in little x region and the effect will become more obvious with decrease of the energy and come to disappear with increase of the x. 相似文献
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HOU Zhao-Yu GUO Ai-Qiang 《理论物理通讯》2007,47(4):690-694
We modify the square of virtual photon four-momentum by using nuclear binding energy formula, and calculate the effect of nuclear binding energy to K factor and Compton subprocess and annihilate subprocess in A-A collision Drell-Yan process. The outcome indicates that the effect of nuclear binding energy to K factor is obvious in little x region and it would disappear gradually as x increases. 相似文献
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在核密度模型基础之上利用原子核密度经验公式得到的核密度和利用电磁半径平方平均值得到的核密度分别计算了轻子 核深度非弹性散射过程中的核效应函数RHe/D(x, Q2), RLi/D(x, Q2), RC/Li(x, Q2), RCa/Li(x, Q2), 发现利用由原子核密度经验公式得到的核密度计算核效应函数所得结果与NMC实验数据符合得较好, 并且优于用后者方法计算核效应函数的理论结果, 从而说明利用原子核密度经验公式研究核子结构函数核效应的合理性。 The nuclear effect functions in l A DIS process RHe/D(x, Q2), RLi/D(x, Q2), RC/Li(x, Q2) and RCa/Li(x, Q2) are calculated on the basis of the nuclear density model by using nuclear densities obtained from an empirical formula or the experimental values of the electromagnetic mean of radius square 〈r2〉, respectively.It is shown that the nuclear effect functions obtained from the empirical formula are in good agreement with the NMC experimental data, and better than the later ones.The empirical formula of the nuclear density can be used to study the nuclear effect of nucleon structure functions reasonably. 相似文献
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Investigation on isospin symmetry in light Lambda hypernuclei is one of the most important issues in hypernuclear physics. In order to know the influences introduced by a single Lambda hyperon, we study the binding energy difference of mirror hypernuclear pair with mass A=16, 18, 28, 40, and 42 using a time-odd triaxial relativistic mean field theory. Effects as the spin-orbit interaction, the time-odd component of vector fields, the core polarization, the proton-neutron mass difference, and the center-of-mass energy correction are self-consistently considered. Compared to the reported results of ordinary nuclei, the binding energy difference of mirror hypernuclei shows trivial change. With core polarization modified by an impurity hyperon, the isospin nonconserving effect between proton and neutron is hardly reduced for nuclei in study. 相似文献
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In this paper, by applying a simplified version of Lieb ‘s spin-refleetion-positivity method, which was recentlydeveloped by one of us [G.S. Tian and J.G. Wang, J. Phys. A: Math. Gen. 35 (2002) 941], we investigate some generalproperties of the boson-fermion Hamiltonian, which has been widely used as a phenomenological model to describe thereal-space pairing of electrons. On a mathematically rigorous basis, we prove that for either negative or positive couplingV, which represents the spontaneous decay and recombination process between boson and fermion in the model, thepairing energy of electrons is nonzero. Furthermore, we also show that the spin-excitation gap of the boson-fermionHamiltonian is always larger than its charged gap, as predicted by the pre-paired electron theory. 相似文献
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本文提出了Li9团簇体心立方结构的形成机理,并对此结构的总能量随中心原子到顶点原子间核间距R的变化用芶氏改进的排列通道量子力学方法(MACQM)进行了计算。结果显示曲线在R = 4.77 a0处有一极小值 -67.160922 a.u.,这表明Li9团簇的体心立方结构是可能稳定存在的。在R趋于无穷大时这9个锂原子的总能量为 -66.852240 a.u.,所以形成Li9的总结合能为0.308682 a.u.。因此Li9 团簇的原子平均结合能是0.034298 a.u.或0.933 eV,它大于我们过去计算的Li5团簇正四面体中心结构的原子平均结合能0.632 eV、Li7 团簇正八面体中心结构的原子平均结合能0.674 eV和Li13 团簇正二十面体中心结构的原子平均结合能0.810 eV。故在体心正多面体结构Lin (n= 5 ,7,9,13)中,Li9的体心立方结构有最大的原子平均结合能,这也许是碱金属晶体的晶胞取体心立方结构的一个原因。 相似文献
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GOU Qing-Quan YANG Jian-Hui LI Ping 《理论物理通讯》2006,46(5):914-918
The formation mechanism for the regular tetrahedral structure of Li4 cluster is proposed. The curve of the total energy versus the separation R between the two nuclei has been calculated by using the method of Gou's modified arrangement channel quantum mechanics (MACQM). The result shows that the curve has a minimal energy of-29.8279 a.u. at R = 14.50 ao. When R approaches infinity the total energy of four lithium atoms has the value of-29.7121 a.u. So the binding energy of Li4 with respect to four lithium atoms is the difference of 0.1158 a.u.for the above two energy values. Therefore the binding energy per atom for Lh is 0.020 a.u., or 0.7878 eV, which is greater than the binding energy per atom of 0.453 eV for Li2, the binding energy per atom of 0.494 eV for Lia and the binding energy per atom of 0.632 eV for Li5 calculated previously by us. This means that the Li4 cluster may be formed stably in a regular tetrahedral structure of side length R = 14.50 ao with a greater binding energy. 相似文献
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GOU Qing-Quan YANG Jian-Hui LI Ping 《理论物理通讯》2006,46(11)
The formation mechanism for the regular tetrahedral structure of Li4 cluster is proposed. The curve of the total energy versus the separation R between the two nuclei has been calculated by using the method of Gou‘s modified arrangement channel quantum mechanics (MACQM). The result shows that the curve has a minimal energy of-29.8279 a.u. at R=14.50 a0. When R approaches infinity the total energy of four lithium atoms has the value of-29.7121 a.u. So the binding energy of Li4 with respect to four lithium atoms is the difference of 0.1158 a.u.for the above two energy values. Therefore the binding energy per atom for Li4 is 0.029 a.u., or 0.7878 eV, which is greater than the binding energy per atom of 0.453 eV for Li2, the binding energy pcr atom of 0.494 eV for Li3 and the binding energy per atom of 0.632 eV for Li5 calculated previously by us. This means that the Li4 cluster may be formed stably in a regular tetrahedral structure of side length R=14.50 a0 with a greater binding energy. 相似文献