Water Wave Packets Over Variable Depth

In this paper, we develop higher‐order nonlinear Schrödinger equations with variable coefficients to describe how a water wave packet will deform and eventually be destroyed as it propagates shoreward from deep to shallow water. It is well‐known that in the framework of the usual nonlinear Schrödinger equations, a wave packet can only exist in deep water, more precisely when kh > 1.363 , where k is the wavenumber and h is the depth. Using a combination of asymptotic analysis and numerical simulations we find that in the framework of the higher‐order nonlinear Schrödinger equations, the wave packet can penetrate into shallow water kh < 1.363 or not even reach kh > 1.363 , depending on the sign of the initial value in deep water of a certain parameter of the wave packet that measures its speed.     

Cationic Complexes of Monovalent Nickel as Catalysts for Styrene Polymerization

The interaction of the [Ni(PPh₃)₃]BF₄ complex with styrene and the products of styrene conversion in the polymerization reaction were studied by EPR and ¹³C NMR spectroscopy. The structure of the σ-carbocationic complex of Ni(I) formed by the interaction of styrene with the [Ni(PPh₃)₃]BF₄ cationic phosphine complex of Ni(I) was characterized in detail. It was found that the reaction of styrene polymerization occurred with the participation of the coordination center of the σ-carbocationic complex (coordination catalysis), whereas the reaction of telomerization occurred with the participation of the cationic center of this complex (ionic catalysis). The resulting polymer contained active terminal double bonds; it is a promising macromonomer for the synthesis of grafted copolymers. The discovered capacity of alcohols to undergo nucleophilic addition to a growing polymer chain offers strong possibilities for preparing functional polymers and block copolymers.     

A new stepwise synthesis of a family of propylamines derived from diatom silaffins and their activity in silicification

A new method for the stepwise synthesis of propylamines containing fragments of N-methyl propylamine as found in diatom bioextracts is presented and their activity in silicic acid condensation is described.     

Effect of diatomite on combustion of poly(vinyl chloride) plastisols

The effect of diatomite on the inflammability, combustibility, and smoke-forming ability of poly(vinyl chloride)-based plastisols has been studied. A substantial decrease in these characteristics takes place upon the introduction of 2–3% diatomite as compared with 10–15% for vermiculite and phlogopite fillers. This phenomenon is associated with a high viscosity of the plastisol melt filled with diatomite and its better foaming and carbonization, along with the formation of a high-porosity coke demonstrating heat-shielding behavior. The use of diatomite also improves the mechanical properties of the tested material.     

Formation of f centers in KCl-KBr solid solutions

The efficiency of F-center formation has been studied as a function of the chemical composition of KC1-KBr solid solutions at room temperature, with ionizing-radiation doses corresponding to the linear stage of the kinetic curve, and at liquid-nitrogen temperature. A qualitative correspondence is found between the composition dependences of the efficiency of F-center formation at room and low temperatures. It is concluded that the fundamental properties of the solid solutions are primarily responsible for the composition dependence of the F-center concentration.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 11, pp. 44–48, November, 1969.     

Temperature dependence of the space charge in alkali halide crystals

Conclusions A theoretical analysis of the mechanism for space-charge formation in ionic crystals must take into account the nature of the crystal defects, the carrier mobility, and the temperature dependence of this mobility. We believe that Eq. (1) best reflects the process of space-charge formation, since it agrees with the experimental results.As the temperature increases, the space charge increases, in agreement with the temperature dependences of the conductivity, the dielectric constant, the capacitance, and the dielectric loss of ionic crystals. The anomalous behavior of the emf corresponding to high-voltage polarization requires a special study.Divalent substitutional cations in alkali halide crystals are not centers for space-charge formation in a polarization layer. They affect the magnitude of the space charge by increasing thenumber of cationic vacancies which enter the crystal along with the impurity and become distributed throughout the lattice.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 1, pp. 132–134, January, 1970.In conclusion the authors thank Professor E. K. Savadovskii, D. Sc., for guidance in this study.     

Aluminum Complexes with a Donor Polymer: New Route to Organic/Inorganic Polymer Hybrids

The formation of alumina particles from aluminum salts in the presence of poly(1-vinylimidazole) was investigated by quantitative ²⁷Al NMR, potentiometry and FTIR spectra. The interaction of poly(1-vinylimidazole) with aluminum chloride and nitrate in an aqueous medium stabilizes [AlO₄Al₁₂(OH)₂₄]⁷⁺ and less ordered polymeric particles. The addition of NaOH (NaOH: Al 2) results in water-insoluble organic/inorganic hydrogen-bonded composites. Stabilization of the complexes is realized by cooperative hydrogen N···H—O—Al bonds, without N Al donor-acceptor interactions.