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A mechanism of the formation of a photodeflection response in a periodically polarized nonlinear crystal illuminated by a Bessel light beam (BLB) is considered. The thermal-field distribution is found, and the exact solution of the system of heat-conduction equations is obtained using the Fourier–Bessel and Laplace integral transforms for a three-layer system consisting of a nonlinear crystal, a substrate, and environment. A method for controlling the amplitude of the photodeflection signal is proposed based on the application of axicons with an adjustable taper angle or optical schemes providing a change in the conicity of BLBs.

—The characteristics of the ultrastructure and functioning of mitochondria in the liver of Sprague Dawley rats in the experimental model of type I diabetes mellitus have been investigated. It has been found that diabetes mellitus induced in response to streptozotocin administration at a dose of 75 mg/kg body weight was accompanied by disturbances in the structural organization of mitochondrial cristae and a decrease in the size of the organelles compared to the control. It has been also demonstrated that in type I diabetes the respiratory rates of liver mitochondria in metabolic states 2, 3, and 4 increase. This may be associated with an increase in the total content of fatty acids in liver mitochondria of diabetic rats. At the same time, streptozotocin-induced diabetes mellitus in rats did not affect the indices of oxidative phosphorylation efficiency (ADP/O, respiratory control ratio, and phosphorylation time) in liver mitochondria.

It has been shown that a cationic copolymer based on poly(aminoethyl methacrylate) is capable of stabilizing silver nanoparticle dispersions in aqueous media. Nanoparticles have been prepared via chemical reduction of AgNO3 in an aqueous solution with sodium borohydride in the presence of a cationic random terpolymer—poly(2-aminoethyl methacrylate-co-N-methyl-2-aminoethyl methacrylate-co-N,N-dimethyl-2-aminoethyl methacrylate). Spectrophotometry has been employed to show that silver dispersions formed in the presence of the copolymer are stable for a long time (more than half a year). Using dynamic light scattering and scanning electron microscopy, consistent information has been obtained on the sizes and size distribution of the stabilized nanoparticles.

Deviations from Archimedes’ principle for spherical molecular hydrogen particles with the radius R0 at the surface of 4He liquid helium have been investigated. The classical Archimedes’ principle holds if R0 is larger than the helium capillary length Lcap ≅ 500 μm. In this case, the elevation of a particle above the liquid is h+ ~ R0. At 30 μm Rc. Here, $${R_c} \cong {\left( {\frac{{\hbar c}}{{\rho g}}} \right)^{1/5}} \approx 1$$ , where ħ is Planck’s constant, c is the speed of light, g is the acceleration due to gravity, and ρ is the mass density of helium. For very small particles (R0 < Rc), the distance h_ to the surface of the liquid is independent of their size, h_ = Rc.

An analysis is made of the karst geomorphosystems of the Yucatan Peninsula. It is found that the main factors influencing its formation were climate and ocean level oscillations, tectonic movements, and impact effects. It is established that as a result of an active influence of the Maya civilization on the karst landscape of the peninsula, the geomorphosystems was transformed to the karst-anthropogenic system. The karstic landforms, and also the underground caverns experienced the anthropogenic impact, and the subsurface waters were particularly heavily influenced, which, on the one hand, determined the places of concentration of settlements and were actively consumed by the population, and, on the other, their reserves were replenished at regular intervals as a result of the creation of artificial subsurface water storages. In a further transformation of the karst-anthropogenic system, two stages were additionally identified: dominated by natural karstic processes (after the decline of the Maya civilization), and with a renewed intensification of anthropogenic pressure (1980s–current period). The last transformation stage is distinguished by an extension of the impact to the surface karst as well as to the underground caverns: they are subjected to mechanical destruction with an enhancement in the chemical impact as a result of inputs of polluted runoffs to encompass ever deeper horizons of subsurface waters. It is established that the rates of transformation processes of anthropogenic objects created of limestone are, in general, comparable with the mean rates of natural karstic processes on the neighboring territories: the formation of karrens on Maya steles is generally proceeding at the rate of 0.04 mm/year, while the growth rates of flowstones within urban structures of limestone vary from 0.03 to 0.6 mm/year.

The polarizability α of many atoms and positive ions is related to their energy gap Δ and valence m by the expression αΔ2 ≅ m (in atomic units). The parameter Δ corresponds to a dipolar transition from the ground state to the first excited P state without a change in the principal quantum number n. This relation holds for univalent (m = 1) Na, K, Rb, Cs, Fr and bivalent (m = 2) Mg, Ca, Zn, Sr, Cd, Ba, Yb, Hg atoms. The above relation agrees with the experiment for positive ions Mg+ and Ca+ (m = 1) and Al+ and Ga+ (m = 2). The polarizability has been found for atoms and ions of the type Zn+, In+, Tl+, for which experimental data are unavailable. A method of calculating α for ions of the types C++, Al++, Si++ and Si+++, P+++, As+++ has been suggested based on the approximate relation α ≅(2/3〈r2〉0)2/m with the parameter 〈r2〉0 expressed in terms of the valence m, the charge number q of the atomic or ionic residue, and the ionization potential $${J_q} = \frac{{{q^2}}}{{2v_s^2}}$$ as $${\left\langle {{r^2}} \right\rangle _0} = \frac{m}{{2{q^2}}}\nu _s^2\left( {1 + 5\nu _s^2} \right)$$ . The hydrogen dependence of 〈r2〉0 on the parameter νs has been derived by analytical continuation from the integer values νs = 1 and 2. A variational estimate of the van der Waals constant characterizing the interaction of two spherically symmetric atoms at large distances has been given.

The Smirnov method of analytic continuation (B.M. Smirnov, Sov. Phys. JETP 20, 345 (1964)) has been justified and developed for atomic physics. It has been shown that the polarizability of alkali atoms α, their van der Waals interaction constant C 6, and the oscillator strength of the transition to the first P state f 01 are related to the parameter 〈r 2〉 and gap in the spectrum \( \frac{3}{2}\frac{f}{\Delta } \approx \frac{3}{2}\alpha \Delta \approx {\left( {3{C_6}\Delta } \right)^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}}} \approx \left\langle {{r^2}} \right\rangle \). The average square of the coordinate of the valence electron 〈r 2〉 in the first approximation has a hydrogen dependence \( {J_1} = \frac{1}{{2{v^2}}}.\) on the filling factor ν, which is defined in terms of the first ionization potential: xxxxxxxxx

The kinetic (K 4 0 (n) and K 3 0 (n)) and potential (V 4 0 (n) and V 3 0 (n)) energies of 4He and 3He atoms have been found from the law of corresponding states and the experimental data on the dependence of the ground-state energies E 4 0 (n) and E 3 0 (n) on the density of the isotopes 4He and 3He. In the approximation of structureless quantum liquid, the potential energies are equal, V 4 0 V 3 0 (n) = (n), and the kinetic energies are inversely proportional to the atomic mass, $$K_4^0 (n) = \frac{3} {4}K_3^0 (n)$$ . The potential energy given by the expression V 0 = 4E 4 0 − 3E 3 0 to a high accuracy is linear in the density n, which is associated with nearly an absence of short-range order in liquid helium. The kinetic energy of liquid 4He is given by the expression K 4 0 = 3(E 3 0 − E 4 0 ), which agrees with the experimental data on neutron scattering in liquid 4He. The quantities K 4 0 (n) and K 3 0 (n) determine the scale of all thermodynamic characteristics in the temperature range where the effects of the particle statistics can be neglected.

We give an outline of the topographic features of the Main Ethiopian Rift and the Afar Triangle as well as of the Ethiopian Highlands. We highlight the role played by the active tectonics and young volcanism which have largely determined the appearance and morphological diversity of contemporary landscapes of Ethiopia. A brief description of several unique natural sites is provided.

Cellulose tridecanoates of various molecular weights were synthesized, and their characteristics in chloroform and tetrachloroethane solutions were studied by methods of translational diffusion, velocity sedimentation, flow birefringence (Maxwell’s method), and viscometry. The effects of solvent and temperature on the conformational characteristics of the macromolecules under consideration were examined. The anisotropy of the monomeric unit of cellulose tridecanoates was studied, and the contribution of pendant chains to the optical anisotropy of macromolecules of cellulose esters with aliphatic substituents was analyzed.

The catalogue of negative ions in superfluid helium has been extended using the example of Ar−, Kr−, and Xe−. Such objects cannot exist in vacuum, since the polarization attraction of an electron to the inert A atom is insufficient for the formation of the bound state A−. However, these objects exist in helium as stable or metastable with a very long lifetime. The effect is due to the electron localization in liquid helium. If a mixture of excited A* atoms and electrons is prepared in the gas phase above liquid helium, the reaction A* + e = A*− becomes possible for all atoms of the periodic table. Such charges can be immersed into liquid helium by the electric field. In this case, the radiative decay A*− = A + e allowed in vacuum can be forbidden in liquid. This leads to the formation of the new unique objects A−, which can exist in liquid helium but are absent in nature. The size of such charged formations has been determined and is close the radius of a usual electron bubble in helium.

The optical, electro-optical, and dynamic characteristics of poly(N-acryloyl-11-aminoundecanoic acid) in organic solvents and of the sodium salt of its monomer in water were studied via the methods of flow birefringence, equilibrium and nonequilibrium electric birefringence, and dynamic light scattering. It is shown that, in aqueous solutions, the monomer forms coarse particles of both symmetric and asymmetric shapes. The linear dimensions of these particles are estimated from the data of translational and rotational diffusion. Polymer macromolecules in organic solvents feature negative anisotropy of optical polarizability. Contributions of optical microform and macroform effects to the observed flow birefringence are analyzed in detail. The intrinsic optical anisotropy of the monomer unit of the polymer, which correlates well with the corresponding values for comb-shaped polymers of a similar structure, is estimated. It is shown that polymer molecules lack marked intrinsic permanent macromolecular dipoles and that electric birefringence in their solutions is associated with macroscopic induced dipole moments that appear during orientation of the dipole moments of polar groups in side chains of the polymer under application of an electric field.

Poly(N-acryloyl-11-aminoundecanoic acid) samples are synthesized in monomer solutions occurring in both micellar and nonmicellar states. It is shown that polymeric ionogenic surfactants of various molecular masses can be prepared through variation in the concentration of a polymerizable surfactant or in the ionic strength of a solution. The polymer of interest is investigated in detail via the methods of molecular hydrodynamics (viscometry, isothermal diffusion, and velocity sedimentation), dynamic light scattering, GPC, and scanning probe microscopy. The solubility of the polymer in various solvents is examined in detail, and the tendency of this polymer toward association in DMF solutions is discovered. The equilibrium rigidity of macromolecules, which is characterized by the Kuhn segment length A = 100 × 10−8 cm, and the effective hydrodynamic radius are determined in a dioxane-cyclohexanol mixed solvent.

Various acrylic polymers in which an aspartic acid fragment with different end groups (the firstgeneration dendron) is attached to the main chain either via the amide group or the 4-aminobenzoic acid residue are studied. The synthesis of monomers and polymers with the asymmetric substitution of the aspartic fragment, in which a long hexadecyl group is situated only at the α-carboxyl group, is described. The molecular, optical, electrooptical, and conformational properties of the polymer containing the long hexadecyl group at the α-carboxyl bond and the hydrolyzed β-ester bond in the aspartic acid fragment are examined in detail. In the range M = (23−508) × 103, the Mark-Kuhn-Houwink equations [η] ∼ M0.53 and D ∼ M−0.53 are obtained for the intrinsic viscosity and diffusion of the polymers under study in octyl alcohol. The length of the statistical Kuhn segment (120 A), the hydrodynamic diameter of a chain (50 A), the shear optical coefficient, and the anisotropies of the segment and monomer unit are determined. An analysis of the experimental data shows that the main optical axis of the side hexadecyl chain makes an angle of ∼54.5° with the direction of the main chain.

The appropriateness of the experimental study of charged clusters in liquid helium has been supported. The interaction potential of negative ions (electron bubbles) with inert clusters formed by Ne, Ar, Kr, and Xe atoms or H2 and N2 molecules has been found. Small clusters levitate at a distance of 13–16 A above the negative ion. The scalings laws for the properties of charged inert clusters have been discovered and grounded; the number of quantum levels and states of such clusters has been determined. The mobility measurement of charged clusters may provide a new technique of probing the properties of impurity nanoparticles in helium.

The problem is studied of reducing the amount of discrete information required for achieving a prescribed accuracy of solving Fredholm integral equations of the first kind on a half-line. The equations are solved by the finite-section method combined with piecewise constant interpolation of the kernel and the right-hand side at uniform grid points. The approximating properties of the discretization schemes are examined, and the corresponding computational costs are analyzed.

A theory of photoresonance transitions for the electrons localized above the solid H2 surface is proposed on the basis of the experimental data obtained by V. V. Zav’yalov and I. I. Smol’yaninov [Pis’ma Zh. Eksp. Teor. Fiz. 44, 142 (1986); Zh. Eksp. Teor. Fiz. 92, 339 (1987); Zh. Eksp. Teor. Fiz. 94, 307 (1988)] and a simple model of condensed hydrogen, H2. A new explanation is offered for the strong dependence of the transition frequency v on the hydrogen vapor pressure revealed in the above-cited works. In contrast to the notions that were proposed by V. V. Zav’yalov and I. I. Smol’yaninov [Zh. Eksp. Teor. Fiz. 92, 339 (1987); Zh. Eksp. Teor. Fiz. 94, 307 (1988)]; and V. B. Shikin and S. N. Nazin [Pis’ma Zh. Eksp. Teor. Fiz. 82, 752 (2005)] and based on the effects of the quantum refraction of electrons by hydrogen vapor atoms, the temperature dependence of the frequency ν = ν (T) is attributed here to the H2 vapor inhomogeneity. The nonanalytic dependence of ν on the vapor density nν, ν(nν) − ν(0) ∼ nνγ ∼ e−Δ/T, γ ≅ 0.56 has been revealed from the experimental data. The activation energy Δ corresponds to the “incomplete evaporation” of solid hydrogen [see J. I. Frenkel, Z. Phys. 26, 37 (1924); Kinetic Theory of Liquids (Nauka, Leningrad, 1945; Clarendon, Oxford, 1946)]. The parameter Δ is lower than the energy of the “complete evaporation” of solid H2 equal to 92.6 K.

The temperature dependence of electron mobility is examined. We calculate the contribution to the electron scattering rate from the surface level atoms (SLAs), proposed in [10]. This contribution is substantial at low temperatures T < 0.5, when the He vapor concentration is exponentially small. We also study the effect of depopulation of the lowest energy subband, which leads to an increase in the electron mobility at high temperature. The results explain certain long-standing discrepancies between the existing theory and experiment on electron mobility on the surface of liquid helium.

An experimental investigation is conducted into the thermal oxidation of GaAs assisted by phosphomolybdic acid. The mechanism of the process is identified. It is established that oxide films thus produced consist mainly of GaPO4 and are superior in insulating performance to ones made by conventional thermal oxidation.

Thermal layer growth on InP in the presence of molybdophosphoric acid (MPA) is studied. An activator added to the system enhances phosphate formation compared to InP thermal oxidation in the absence of H7[P(Mo2O7)6] · nH2O.

In a strong electric field, there are bound states of an electron at the surface of liquid helium, interacting with a large cluster of atoms in the bulk of liquid. This phenomenon is related to long-range interaction between the electron and the dipole moment of the cluster. The electron, holding the cluster under the liquid surface, is localized at this surface. One electron is capable of binding a cluster of up to 106 atoms. The value of the binding energy may reach up to several kelvins.

The evolution of the form of first-sound waves, excited in superfluid He-II by a pulsed heater, with increasing power Q of the perturbing heat pulse is investigated. In liquid compressed to 13.3 atm, a first-sound rarefaction wave (wave of heating) is observed, which transforms into a compression wave and then into a compression shock wave as Q increases, i.e., the change in the conditions of heat transfer at a solid-He-II interface can be judged according to the change in the form of the sound wave. It follows from our measurements that in He-II compression waves are excited at pressures P⩾1 atm primarily as a result of the thermal expansion of a normal He-I liquid layer arising at the He-II-heater interface for power Q above a critical level.

The problem of the equilibrium form of a charged surface of a dielectric liquid in a strong electric field, such that a flat surface becomes unstable, is studied. A periodic long-wavelength structure with a small amplitude can arise when the gap between the surface and a charged electrode is small compared with the capillary length and the charge completely screens the electric field. The equilibrium form of the surface is calculated assuming that the resulting wave is one-dimensional. The effect of the boundary conditions at the vessel walls on the dependence of the amplitude of the standing wave on the applied voltage is estimated. It is shown that this dependence is very sensitive to the conditions of contact between the vessel walls and the liquid. The possibility is discussed of using the theory developed in this paper to explain the experimental results obtained with a charged liquid-hydrogen surface.

The interaction potential of negative ions (electron bubbles) with the surface of liquid 4He, 3He, and Ne has been found. In addition to the electrostatic repulsion, the contribution of the long-range Van der Waals attraction of the electron bubble to the liquid surface has been also taken into account. Competition of these repulsion and attraction forces results in the formation of a potential barrier that prevents the motion of a negative ion from the liquid to the vacuum. The temperature and electric-field dependences of the lifetime of the bubble have been determined. The theory has been compared with the experiments with negative ions in liquid 4He. In contrast to the conventional idea based on the hypothesis of the quantum tunneling of an electron from a bubble to a vacuum, our theory is based on the Kramers’ diffusion model of the classical escape of the bubble over the potential barrier. In this model, a low-dynamic-friction approximation is applicable to liquid 4He owing to a high mobility of negative ions in the superfluid.