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101.
对光磁共振实验中测量gF值的方法的评述和改进 总被引:2,自引:2,他引:2
对文献中测量gF因子的方法进行了评述,阐述了如何基于三角波扫场,用抽运信号确定计算和测量gF的方法。 相似文献
102.
I. Ursu I. Apostol D. Bǎrbulescu I.N. Mihǎilescu M. Moldovan A.M. Prokhorov V.P. Ageev A.A. Gorbunov V.I. Konov 《Optics Communications》1981,39(3):180-185
The analysis of some new experimental data has proved that the evaporation of a stainless steel target in vacuum under the action of powerful TE-CO2 microsecond pulsed laser radiation is initiated on the initial spike or not at all. The minimum “tail” duration to get evaporation was deduced as a function of the temporal pulse shape characteristics and the metal thermophysical properties. The vaporisation process was accompanied by nonequilibrium heating of vapour clouds leading to the target surface shielding. Two self-regulated evolutions were recognised which were attributed to the intense vaporisation and the target evaporation by the UV plasma emitted radiation, respectively. 相似文献
103.
104.
WANG Dian-Fu SONG He-Shan MI Dong 《理论物理通讯》2004,42(9)
In terms of the Nambu-Jona-Lasinio (NJL) mechanism, the dynamical symmetry breaking of a simple localgauge model is investigated. An important relation between the vacuum expectation value of gauge fields and scalarfields is derived by solving the Euler equation for the gauge fields. Based on this relation the SU(3) gauge potential isgiven which can be used to explain the asymptotic freedom and confinement of quarks in a hadron. The confinementbehavior at finite temperatures is also investigated and it is shown that color confinement at zero temperature can bemelted away under high temperatures. 相似文献
105.
106.
Bogdan F. Apostol 《Central European Journal of Physics》2013,11(8):1036-1044
The classical theory of scattering of longitudinal waves (sound) by small inhomogeneities (scatterers) in an ideal fluid is generalized to a distribution of scatterers and such as to include the effect of the inhomogeneities on the elastic properties of the fluid. The results are obtained by a new method of solving the wave equation with spatial restrictions (caused by the presence of the scatterers), which can also be applied to other types of inhomogeneities (like surface roughness, for instance). A coherent forward scattering is identified for a uniform distribution of scatterers (practically equivalent with a mean-field approach), which is due to the fact that our treatment does not include multiple scattering. The reflected wave is obtained for a half-space (semi-infinite fluid) of uniformly distributed scatterers, as well as the field diffracted by a perfect lattice of scatterers. The same method is applied to a (inhomogeneous) rough surface of a semi-infinite ideal fluid. A perturbation-theoretical scheme is devised, with the roughness function as a perturbation parameter, for computing the waves scattered by the surface roughness. The waves scattered by the rough surface are both waves localized (and propagating only) on the surface (two-dimensional waves) and waves reflected back in the fluid. They exhibit directional effects, slowness, attenuation or resonance phenomena, depending on the spatial characteristics of the roughness function. The reflection coefficients and the energy carried on by these waves are calculated both for fixed and free surfaces. In some cases, the surface roughness may generate waves confined to the surface (damped, rough-surface waves). 相似文献
107.
108.
M. Apostol 《理论物理通讯》1993,20(2):249-252
The phason contributions to the lattice heat capacity and thermoconductivity are obtained in the low-temperature limit for quasi-one-dimensional compounds. They are concentrated around temperatures related to the pinning frequency and the heat capacity is controlled by the density of states while the thermo,conductivity is governed by the phason velocity. 相似文献
109.
合成了3个系列芳香类含碳一氧键的化合物,用循环伏安法测定了相关的氧化还原电势,通过热力学循环首次估测了负离子基的碳-氧键的断裂能量(ΔHcleav[C-O]·-).结果表明:得到1个电子形成负离子基可以活化碳-氧键。这与具有相同结构的正离子基的情况是一致的,但其活化程度略小。相关分析表明:ΔHcleav[C-O]·-vs(ΔEred[C-O]+ΔpKa[HA])和ΔHcleav[C-O]·+vs.(ΔBDE-ΔEox[C-O])均呈线性。讨论了负离子基和正离子基及其母体化合物中键的特征,并与文献中有关的键能数据进行了比较。 相似文献
110.
新型冠状病毒感染疫情是重大突发公共卫生事件,对全球公共心理健康产生了深远影响.本文对公众心理健康状况、影响心理健康水平的疫情因素(新型冠状病毒感染、隔离、失业和其他应激源)以及个人因素(青少年、女性、医护人员和既往有躯体/精神疾病史)进行综述,并从个人、社会、国家层面分析改善公众心理健康的对策,为应对疫情的长期影响提供参考. 相似文献