共查询到20条相似文献,搜索用时 78 毫秒
1.
2.
3.
4.
5.
对两对重离子中心碰撞系统40C 40ca和60ca 40Ca以及112Sn 112Sn和124Sn 124Sn反应中就同位素标度参数n对于核子一核子碰撞截面的同位旋效应进行了研究.计算结果表明a对同位旋相关核子.核子碰撞截面amedNN(am)相对于同位旋无关核子一核子碰撞截面口aNN(am)的同位旋效应很明显,然而a对amedNN(am)相对于同化旋无关核子-核子碰撞截面a2nn(am)的同位旋效应是较小的.对以上两种条件下a同位旋效应的机理进行了仔细研究. 相似文献
6.
7.
8.
用同位旋相关的晶格气体模型系统地研究了Z=54的同位素和A=129的同质异位素热发射体的粒子发射的特性,阐述了发射体系的同位旋对中子、质子和带电粒子产额,以及轻粒子的同位素比及同位素对的比的影响.同时,还比较了在同位旋相关作用势下和同位旋不相关作用势下碎片产物特性的差异.发现了不同质量区间(轻粒子、中等质量碎片和重余核)的产物的平均中子质子比,在同位旋相关的或不相关的作用下它们有十分不同的温度依赖性.发现核气态(轻粒子)的要大于核液态(重余核)的,也就是说在液气共存时的气态有
关键词: 相似文献
9.
10.
11.
R.K. Das 《Journal of magnetism and magnetic materials》2010,322(17):2618-2621
The magnetic properties of thin-film Pd/Fe/Pd trilayers in which an embedded - thick ultrathin layer of Fe induces ferromagnetism in the surrounding Pd have been investigated. The thickness of the ferromagnetic trilayer is controlled by varying the thickness of the top Pd layer over a range from 8 to . As the thickness of the top Pd layer decreases, or equivalently as the embedded Fe layer moves closer to the top surface, the saturated magnetization normalized to area and the Curie temperature decreases, whereas the coercivity increases. These thickness-dependent observations for proximity-polarized thin-film Pd are qualitatively consistent with finite size effects that are well known for regular thin-film ferromagnets. The critical exponent β of the order parameter (magnetization) is found to approach the mean field value of 0.5 as the thickness of the top Pd layer increases. The functional forms for the thickness dependences, which are strongly modified by the nonuniform exchange interaction in the polarized Pd, provide important new insights to understand nanomagnetism in two-dimensions. 相似文献
12.
We investigate the supersymmetry properties of energy dependent potentials in the D=1 dimensional space. We show the main aspects of supersymmetry to be preserved, namely the factorization of the Hamiltonian, the connections between eigenvalues and wave functions of the partner Hamiltonians. Two methods are proposed. The first one requires the extension of the usual rules via the concept of local equivalent potential. In this case, the superpotential becomes depending on the state. The second method, applicable when the potential depends linearly on the energy, is similar to what has been already achieved by means of the Darboux transform. 相似文献
13.
提出在QED中利用自由场的量子化条件和场方程,可以全面解决独立和非独立的相互作用场中¢(x),Aμ(x)的量子化问题.证明了:(1)当外规范场(x)≠0时,¢(x)与Aμ(x)相互独立,它与常规的场量子化方法一致.(2)当(x)=0时,¢(x)与Aμ(x)不再相互独立,常规的量子化方法不再适用,而本文提出的方法继续有效.并以1+1维QED作为实例. 相似文献
14.
We derive an explicit autocorrelation function (ACF) formula of state of polarization for a fiber transmission system with polarization mode dispersion (PMD) and polarization dependent loss (PDL), which is found to agree well with Monte Carlo simulation. Then we use the new ACF to investigate the combined effect of PMD and PDL on the polarization multiplexed scheme. We find the performance of the polarization multiplexed scheme can be deteriorated more severely than the case without PDL. 相似文献
15.
We improve the isospin dependent quantum molecular dynamical model by including isospin effects in the Skyrme potential and the momentum dependent interaction to obtain an isospin dependent Skyrme potential and an isospin dependent momentum interaction. We investigate the isospin effects of Skyrme potential and momentum dependent interaction on the isospin fractionation ratio and the dynamical mechanism in intermediate energy heavy ion collisions. It is found that the isospin dependent Skyrme potential and the isospin dependent momentum interaction produce some important isospin effects in the isospin fractionation ratio. 相似文献
16.
17.
Silvia Tardioli Cees Gooijer Gert van der Zwan 《Journal of Raman spectroscopy : JRS》2011,42(5):1016-1024
Ultraviolet Resonance Raman (UVRR) spectroscopy—a Raman technique that combines high sensitivity with high selectivity and does not suffer from background fluorescence—is applied to the fluorescent H1 antihistamines tripelennamine (TRP) and mepyramine (MEP) in aqueous solution to elucidate their molecular structure as a function of pH. In a previous investigation of these compounds (C. Tardioli, G. Gooijer G. van der Zwan, J. Phys. Chem. B, 113 , (2009), 6949), the presence of gauche conformers caused by intramolecular interaction of the protonated alkylamine tail with the pyridine nitrogen was assumed to explain the pH dependence of the fluorescence properties. In order to validate this assumption, use is made of the resonant excitation of the aminopyridine chromophore in TRP and MEP. In that way, structural information associated with the vibrations of that moiety can be obtained, and the changes it undergoes upon protonation can be monitored. Assignment of the vibrations was achieved with the help of a number of other compounds, and quantum chemical calculations. N,N‐Dimethylaminopyridine (2DMP) and its mono‐protonated form (2DMPH+) were investigated, since this molecule was shown to have optical properties closely resembling those of the aminopyridine moiety in TRP and MEP. Assignment of the vibrations of 2DMP was accomplished by comparison with the resonance Raman spectra of two other reference structures, 2‐aminopyridine and dimethylaniline—for which ordinary Raman data are available—and by Gaussian calculations. UVRR spectra of TRP and MEP could be readily interpreted on the basis of vibrational assignments of the parent chromophores, i.e. 2DMP and 2DMPH+. Vibrations of the aminopyridine chromophore in TRP and MEP at neutral pH, where the aminoalkyl chain is protonated, are modified when compared to the vibrational pattern recorded for a fully neutral molecule in alkaline solution. This implies an electronic redistribution in the ring originating from internal hydrogen bonding between the aminoalkyl tail and the aminopyridine chromophore. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
18.
利用表面镀金阴极膜的微通道板(MCP)构成一种金阴极MCP光电探测器,根据MCP的电阻电容特性提出了一种特殊的能谱响应测量方法。在北京同步辐射3B3中能束线上对该探测器在2.1~6.0 keV能段的谱响应进行了实验标定。以美国NIST绝对定标的美国IRD公司生产的AXUV-100硅光二极管为次级标准探测器,标定金膜厚度分别为25和100 nm的金阴极MCP探测器的能谱响应。经分析发现,阴极材料和MCP材料的元素吸收边是造成量子效率曲线出现突变点的原因。对比两种MCP的能谱响应标定结果,金膜厚度为100 nm探测器的能谱响应高于金膜厚度为25 nm的探测器。 相似文献
19.
Serkan Caliskan 《Physics letters. A》2013,377(28-30):1766-1773
Spin polarized Density Functional Theory combined with Non-Equilibrium Green?s Function Formalism is applied to investigate the spin dependent transport in carbon based monatomic systems. Both one-dimensional linear and ring structures sandwiched between spin polarized nickel electrodes are examined. Incorporating of nickel electrodes and rings leads to interesting spin dependent properties. The influence of electrode structure is also addressed, using the Ni(100) pyramidal and plane electrodes. It is revealed that spin dependent behavior is largely determined by the atomic arrangement of the monatomic system, and that both the transport and magnetic properties can be tuned by odd–even disparity and/or appropriate ring(s). The mechanisms governing the spin dependent properties in these structures are discussed. 相似文献