Synthesis of bis(difluoronitroacetoxy)iodoarenes

Two methods for synthesizing bis(difluoronitroacetoxy)iodoarenes, new compounds of tervalent iodine, have been proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1629–1630, September, 1994.This work was carried out with the financial support of the Russian Foundation for Basic Research (Project No. 93-03-4566).     

涡旋成对分布和对二元速度关联函数的影响

本文考虑了涡旋之间相互作用的影响,假定均匀各向同性湍流场是由涡旋对在整个空间等几率分布而成,这样计算出的二元速度关联函数f(γ/λ)在远处略有提高,这个结果是与Bennett和Corrsin的实验结果和其他实验结果相合的。     

Anomalous transport of macromolecules in solution

Based on a semi-phenomenological Fokker-Planck approach, we present and discuss a theoretical framework for studying the transport properties of macromolecules in solution. A formally exact expression for the diffusion of macromolecules is derived and utilized in order to show the anomalous character of the macromolecular diffusion, both at very short times, t→ 0, as well as in the asymptotic limit, t→∞. Numerical computations for 50- and 100-bead macromolecules demonstrate moreover a `superdiffusive' behaviour at short and intermediate times when compared with the data from the (Einstein's) phenomenological theory.     

Λ and Λ production in K+p interactions at 32 GeV/c

A study of the inclusive and semi-inclusive Λ and $\text{Λ}$ production in K⁺p interactions at 32 GeV/c is presented. The inclusive cross sections for Λ and $\text{Λ}$ amount to 0.78 ± 0.05 and 0.42 ± 0.04 mb thus showing a remarkable growth between 16 and 32 GeV/c with a factor of 1.7 for Λ and 2.8 for $\text{Λ}$. Target and beam fragmentation processes are found to be dominant for Λ and $\text{Λ}$ production respectively with the following lower limits for the corresponding cross sections: $\text{σ(p}\text{→}\text{K}{}^{\mathrm{+}}\text{?) > 0.5}\text{mb}$ and $\text{σ(K}{}^{\mathrm{+}}\text{→}\text{p}\text{?}\text{) > 0.3}\text{mb}$. Although the early scaling conditions are fulfilled for the Λ production in the target fragmentation region, and $\text{Λ}$ production in the beam fragmentation region, scaling is not observed between 16 and 32 GeV/c in the x and p_T² Feynman variables. The Λ production is found to be very similar in the K⁺p inclusive reaction at 32 GeV/c and in the semi-inclusive reaction $\text{K}{}^{\mathrm{?}}\text{p}\text{→ Λ}\text{K}\text{K}\text{X}$ at the same energy. The $\text{Λ}\text{Λ}$ pair production cross section increases significantly in K⁺p interactions from 16 to 32 GeV/c where it reaches the value $\text{σ}{}_{\mathrm{<mtext>\Lambda </mtext><mtext>\Lambda </mtext>}}\text{= 47 ± 11 μ}\text{b}$. The cross sections for Λ or $\text{Λ}$ produced in association with an identified proton are also given and discussed.     

NH3+自由基离子的电子自旋共振

本文研究了俘获于掺杂VO⁺⁺离子的(NH₄)₂Zn(SO₄)₂·6H₂O单晶中NH₃⁺自由基离子的ESR.从实验上分别测出π电子自由基NH₃⁺的¹⁴N和¹⁵N核超精细分裂.结果表明,氮核超精细偶合张量具有近似于圆柱形对称。对于¹⁵N来说,A₁₁=44.8,A₂₂=19.3,A₃₃=17.8高斯.对于¹⁴N来说,A₁₁=31.1,A₂₂=12.5,A₃₃=11.8高斯.在室温下,NH₃⁺自由基绕A₁₁方向作圆锥体运动.文中最后讨论了NH₃⁺自由基离子的可能生成机理。     

Internal Mobility, Phase Transitions, and Ionic Conductivity in Na(NH4)6Zr4F23 and Li(NH4)6Zr4F23

The dynamics of fluoride and ammonium ions in Na(NH₄)₆Zr₄F₂₃ (I) and Li(NH₄)₆Zr₄F₂₃ (II) was studied by ¹H and ¹⁹F NMR in the temperature range 170-440 K. Types of ionic motion were determined, and their activation energies were evaluated. In I, phase transitions were found in the temperature ranges 360-370 and 410-415 K. The experimental values of conductivity of Na(NH₄)₆Zr₄F₂₃ and Li(NH₄)₆Zr₄F₂₃ ( 4 × 10^-3 S/cm at T = 420 K) permit one to attribute these fluorides to the class of superionic conductors.     

Karman Vortex Street in a Vibrationally Nonequilibrium Gas

The problem of vibrationally nonequilibrium gas flow past a cylinder with the formation of a Karman street is considered. The effects of relaxation on the flow parameters, namely, on vortex damping and deformation, is analyzed on the basis of a numerical simulation. A theoretical explanation of these effects is proposed.     

Interaction of Small Hydrodynamic Perturbations with a Nonequilibrium Region in a Gas Flow

The problem of interaction of small hydrodynamic perturbations with a nonequilibrium region in a Gas flow with different models of energy pumping is solved. One-dimensional and two-dimensional interactions are considered. A range of system parameters is found in which interaction occurs in a resonant manner (significant amplification of perturbations is observed). It is demonstrated that interaction of vortex perturbations with the nonequilibrium region generates heat waves. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 6, pp. 58–64, November–December, 2005.