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Dissipationless relaxation kinetics of the superfluid turbulence is analyzed. The possibility and scenario of a specific Kolmogorov-like regime are revealed. Qualitative considerations are corroborated by numerical study of a simplified model of a self-crossing vortex line.

Single-walled carbon nanotubes (SWCNTs) encapsulating $\ensuremath{\beta}$-carotene are attractive components for enhancing optical functionalities of SWCNTs. We have investigated ultrafast dynamics of light-harvesting function of $\ensuremath{\beta}$-carotene. The relaxation kinetics of $\ensuremath{\beta}$-carotene is faster in SWCNTs than in nonpolar solvent. The absorbance change due to SWCNTs increases with the encapsulation because of excited energy transfer from $\ensuremath{\beta}$-carotene. The energy transfer rates from the $1\phantom{\rule{0.2em}{0ex}}^{1}B_{u}^{+}$ and $2\phantom{\rule{0.2em}{0ex}}^{1}A_{g}^{\ensuremath{-}}$ excited states of $\ensuremath{\beta}$-carotene to SWCNTs are determined to be ${(50\phantom{\rule{0.3em}{0ex}}\mathrm{fs})}^{\ensuremath{-}1}$ and ${(6.6\phantom{\rule{0.3em}{0ex}}\mathrm{ps})}^{\ensuremath{-}1}$, respectively.

Relaxation kinetics of photoexcitation in a blue-phase polydiacetylene has been investigated by difference absorption spectroscopy with extremely high time- and energy-resolution using broadband sub-$5\text{\ensuremath{-}}\mathrm{fs}$ optical pulses. One-fs-step tracking of an induced emission peak has enabled us to separate the vibrational dynamics during geometrical relaxation and internal conversion into modulations of transition-peak energy and transition probability. The peak energy shows redshift of about $60\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$ and the instantaneous frequency of the ``$\mathrm{C}\mathrm{C}$'' stretching mode is positively ``chirped'' starting from $1600\ifmmode\pm\else\textpm\fi{}100\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ $(21\ifmmode\pm\else\textpm\fi{}2\phantom{\rule{0.3em}{0ex}}\mathrm{fs})$ and ending in $2100\ifmmode\pm\else\textpm\fi{}100\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ $(16\ifmmode\pm\else\textpm\fi{}1\phantom{\rule{0.3em}{0ex}}\mathrm{fs})$. This positive chirp indicates a huge dynamic structural change from ${(\mathrm{C}R\mathit{C}\mathit{C}\mathrm{C}{R}^{\ensuremath{'}})}_{n}$\char21{}like to ${(\mathrm{C}R\mathrm{C}\mathrm{C}\mathrm{C}{R}^{\ensuremath{'}})}_{n}$\char21{}like structured bonds in the polymer backbone during the internal conversion process within $100\phantom{\rule{0.3em}{0ex}}\mathrm{fs}$. This corresponds to the reduction of the bond length from $1.32\ifmmode\pm\else\textpm\fi{}0.04\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ to $1.19\ifmmode\pm\else\textpm\fi{}0.04\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ by about $0.13\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$, which was estimated from the bond lengths in literatures determined by the x-ray analysis for several polydiacetylenes.

The specific features of relaxation kinetics in systems with different kinds of confinements are discussed in the paper. In contrast to the usual Arrhenius, Eyring, or Vogel-Fulcher-Tammann patterns, a quite unusual nonmonotonic dependence of relaxation time versus temperature is observed in such systems. Based on the free volume concept, a model for this type of kinetics was illustrated by several particular examples: water conlined in porous glasses and in zeolites, confined liquid crystals, doped ferroelectric crystals, and heteropolymer folding.

We have studied the approach to equilibrium of islands and pores in two dimensions. The two-regime scenario observed when islands evolve according to a set of particular rules, namely relaxation by steps at low temperature and smooth at high temperature, is generalized to a wide class of kinetic models and the two kinds of structures. Scaling laws for equilibration times are analytically derived and confirmed by kinetic Monte Carlo simulations., 6 pages, 7 figures, 1 table

Anelastic processes in Al single crystals present after low-temperature electron irradiation have been investigated using both internal-friction and elastic-aftereffect techniques. Several stress-induced relaxation processes have been observed, one due to the ${I}_{B}$ close-pair defect, and six others attributed to small interstitial clusters formed during long-range interstitial migration in recovery stage I. Details are presented concerning the creation, stability, symmetry, and relaxation kinetics of the various defects responsible for the anelastic processes. One of the processes exhibits all the characteristics expected for a configuration of the di-interstitial proposed by Johnson. A model is discussed which suggests how a small interstitial cluster may undergo reorientation without simultaneous migration of the defect center of mass.