Dynamic surface tension of micellar solutions in the millisecond and submillisecond time range

The analysis of the available bubble life times and dead times for the bubble pressure tensiometer BPA-1S shows that dynamic surface tensions can be measured also for surfactant solutions at concentrations many times higher than the corresponding CMC. For the three nonionic surfactants Triton X-100, Triton X-45, and C14EO8 experiments are performed for solutions with a concentration of up to 200 times the CMC (C14EO8). Comparison of the experimental data with micelle kinetics models yields rate constants for the fast micelle dissolution process, which are in a good agreement with values obtained by other experimental methodologies.     

Constraints on the number density of evaporating primordial black holes for the chromospheric evaporation models

Cosmic gamma-ray bursts with primary-photon energies ≥ 10 GeV are sought in the data from the Andyrchy array obtained in the mode of detection of a single cosmic-ray component during a net observation period of 2005.4 d. The distribution of fluctuations of the detector count rate agrees with the expected cosmic-ray background, the only exception being an event with a deviation of 7.9σ. Constraints on the number density of evaporating primordial black holes in a local region of the Galaxy are obtained for the chromospheric evaporation models.     

Cauchy problem for effectively hyperbolic operators with triple characteristics

We study a class of third-order effectively hyperbolic operators P   in G={(t,x):0?t?T,x∈U?Rⁿ}$G=\{(t,x):0?t?T,x\in U?{\mathbb{R}}^n\}$ with triple characteristics at ρ=(0,x₀,ξ),ξ∈Rⁿ?{0}$\rho =(0,x_0,\xi ),\xi \in {\mathbb{R}}^n?\{0\}$. V. Ivrii introduced the conjecture that every effectively hyperbolic operator is strongly hyperbolic  , that is the Cauchy problem for P+Q$P+Q$ is locally well posed for any lower-order terms Q. For operators with triple characteristics, this conjecture was established [3] in the case when the principal symbol of P admits a factorization as a product of two symbols of principal type. A strongly hyperbolic operator in G could have triple characteristics in G   only for t=0$t=0$ or for t=T$t=T$. The operators that we investigate have a principal symbol which in general is not factorizable and we prove that these operators are strongly hyperbolic if T is small enough.     

Studying the muon and hadron components of extensive air showers with the Carpet-2 array

The method of separating muons and hadrons recorded by the Muon Detector of the Carpet-2 air shower array of Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) is described. The results of studying characteristics of the muon and hadron components of extensive air showers (EAS) with N _e ≥ 10⁵ are presented. For the range of distances 40–55 m from shower axes the numbers of hadrons with energies higher than 30 GeV and muons with energies above 1 GeV are obtained as functions of the shower size N _e .     

Estimates of holomorphic functions in zero-free domains

We study functions f(z) holomorphic in having the property f(z) ≠ 0 for 0 < Im z < 1 and we obtain lower bounds for |f(z)| for 0 < Im z < 1. In our analysis we deal with scalar functions f(z) as well as with operator valued holomorphic functions I + A(z) assuming that A(z) is a trace class operator for and I + A(z) is invertible for 0 < Im z < 1 and is unitary for . A. Borichev was partially supported by the ANR project DYNOP.     

On the tautomerism of 1-phenyl-3-substituted-pyrazol-5-ones and their photoinduced products — experimental and theoretical UV spectral analysis

A detailed experimental and theoretical UV-spectral analysis of the tautomeric forms of 3-methyl-1-phenyl pyrazol-5-one and 1,3-diphenyl pyrazol-5-one as well as of the UV-irradiated photoinduced products of the latter compound were carried out. The experimental UV-spectra were compared with the theoretical ones obtained by CIS/6-31G**. Selected geometrical parameters of the different tautomers were estimated by ab initio calculations using the RHF/6-31G** level of theory and basis set, which have also been discussed with a view to the corresponding UV-results.     

In-band M1 and E2 transition rates and collective structures in Ba

Subpicosecond mean lifetimes of eight excited states in ¹²⁸Ba populated via the ⁹⁶Zr(³⁶S,4n) reaction were measured by the Doppler-shift attenuation (DSA) technique using a line-shape analysis. The differential decay-curve method (DDCM) was applied for the lifetime determination. The B(E2) values in the yrast band indicate that the first band-crossing is with a proton S-band. The configuration πh_11/2d_5/2 of the negative-parity semi-decoupled bands is confirmed by the measured B(E2, I → I − 2) and B(M1, I → I − 1) transition strengths. The higher-lying “dipole” band in ¹²⁸Ba can be described as a high-K four-quasiparticle band built on the prolate configuration (πh_11/2d_5/2) (νh_11/2g_7/2).     

On the photosensitivity of dibenzoylmethane,benzoylacetone and ethyl benzoylacetate in solution

The influence of sunlight on the keto-enol ratio of dibenzoylmethane, benzoylacetone and ethyl benzoylacetate in heptane solution was examined. It was shown that the tautomeric equilibrium is strongly displaced to the keto form. Important differences in the photosensitivity of β-diketones and β-ketoesters depending on the structural features and the nature of irradiation have been established.     

Some M1 transition strengths in odd-A nuclei away from closed shells

By the in-beam application of the generalized centroid shift method, nanosecond half-lives have been determined for the first time: in ${}^{101}\text{Pd}\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(1337.4}\text{keV}\text{) = 1.2}{}^{\mathrm{+0.6}}{}_{\mathrm{?0.3}}\text{ns and}\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(261.0}\text{keV}\text{) = 0.7 ± 0.2}\text{ns}$ using the reaction $\text{(}{}^{12}\text{C}\text{,x}\text{n}\text{)}$, in ${}^{71}\text{As}\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(147.5}\text{keV}\text{) = 0.85 ± 0.25}\text{ns}$ using the reaction (¹⁶ O, αp), in ${}^{91}\text{Nb}\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(5455.3}\text{keV}\text{) = 1.2 ± 0.3}\text{ns}$ using the reaction (¹⁶O,2np), in ${}^{103}\text{Pd}\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(244.0}\text{keV}\text{) < 0.2}\text{ns}$ and in ${}^{91}\text{Nb}\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(3110.2}\text{keV}\text{) < 0.2}\text{ns}$ using the reaction P(α, xn). Some known nanosecond isomers in different nuclei produced as by-products have also been detected. In the nuclei investigated far away from closed shells with complex wave functions, M1 transitions are considered which would be l-forbidden in the pure shell model. A retarded $\text{Ml}\text{(+}\text{E}\text{2)}\text{25}\text{2}{}^{\mathrm{+}}\text{→}\text{23}\text{2}{}^{\mathrm{+}}$ transition in ⁹¹ Nb is considered as proceeding between possible multiparticle-hole configurations.