Anisotropic field of background internal waves on a sea shelf and its effect on low-frequency sound propagation

The space-time spectral characteristics of the field of background internal waves (IW) are obtained for two oceanic shelf regions (the Atlantic shelf of the United States and the Kamchatka shelf) and analyzed. Within the framework of a numerical experiment, it is shown that the observed anisotropy of the IW field may considerably affect the low-frequency sound fluctuations in the aforementioned regions and, in particular, may change the interference invariant of the sound field.     

The structure of an Fe monolayer on the Ni (111) surface. A density-functional study using the generalized gradient approximation

Using a density-functional method that employs linear combinations of atomic orbitals as basis sets, nonlocal norm-conserving pseudopotentials and the generalized gradient approximation for exchange and correlation, we found that at 0 K the atoms of an Fe monolayer on the Ni (111) surface occupy hcp rather than fcc sites, in keeping with previous predictions made using the ab initio all-electron full-potential linearized augmented plane wave method with the local spin density approximation.     

Polarizability of the fine-structure components of low excited states of the F, Cl, and Br atoms

The dynamic scalar, tensor, and pseudovector polarizabilities of the low excited states (ns)⁴ P _J of the F, Cl, and Br atoms (n = 3, 4, and 5, respectively) are calculated for all the levels of the fine-structure multiplets with J = 5/2, 3/2, and 1/2 with the use of the quantum detect Green’s function, proposed earlier.     

Reaction of 2-formyl-1,3-cyclohexanediones with cyanoacetamide

Chemistry of Heterocyclic Compounds -     

薄原子蒸汽膜的双光子光谱及Dicke窄化

薄原子蒸汽膜的单光子Dcike窄化吸收光谱可以拓展到双光子情形，以级联三能级系统为例,从理论上得到了亚多普勒结构的双光子吸收光谱，其线型表现出和单光子过程相似的与膜厚和探测光波长的比值(L/λ)相关的周期性.当L/λ=(2n+1)/2(膜厚为半波长的奇数倍)时，吸收谱线窄化现象明显.当L/λ=2n/2(膜厚为半波长的偶数倍)时，单光子情形的谱线窄化现象消失，而双光子情形的谱线仍表现为亚多普勒结构，尤其在异侧入射的情形下，可以获得极窄的双光子谱线结构. 这种结构来自原子与腔壁碰撞的消激发效应和双光子过程的抽运-探测机制的贡献. 关键词： 薄原子蒸汽膜 双光子光谱 Dicke窄化     

纳米晶ZrO2:Er3+-Yb3+的制备及其室温上转换发射

用化学共沉淀法制备了ZrO₂:Er³⁺-Yb³⁺纳米晶粉体，所制备的纳米晶粉体具有较强的室温上转换发射和红外发射.研究了样品的晶体结构和上转换发光性质随着Yb³⁺掺杂浓度和煅烧温度的变化关系.通过X射线衍射谱分析发现，经800℃煅烧2h后得到的ZrO₂:Er³⁺-Yb³⁺纳米晶是四方相和单斜相的混合结构，经950℃煅烧2h后得到的样品以单斜相为主，随着Y     

Characteristic features of carbazole phosphorescence quenching by benzophenone molecules in toluene at 77 K

We have studied the characteristic features of carbazole phosphorescence quenching by benzophenone in toluene at 77 K. We have shown that the decrease in the relative phosphorescence intensity for carbazole (energy donor) by a greater factor than we see for the relative change in its decay time is due to the fact that a change in the phosphorescence decay time occurs only for carbazole molecules participating in triplet-triplet energy transfer, while the substantial decrease in the phosphorescence intensity for carbazole with no change in the phosphorescence decay time is connected with quenching of its singlet states. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 554–556, July–August, 2006.