Rhythmic pattern formations in gels and Matalon—Packter law: A fresh perspective

The periodic precipitation pattern formation in gelatinous media is interpreted as a moving boundary problem. The time law, spacing law and width law are revisited on the basis of the new scenario. The explicit dependence of the geometric structure on the initial concentrations of the reactants is derived. Matalon—Packter law, which relates the spacing coefficient with the initial concentrations is reformulated removing many ambiguities and impractical parameters. Experimental results are discussed to establish the significance of moving boundary concept in the diffusion controlled pattern forming systems     

Fermi and Coulomb correlations in the 21 S state of the helium isoelectronic sequence

The Fermi and Coulomb holes of the 2¹ S state of the helium isoelectronic sequence are investigated. Several interesting differences between the results obtained and those which might be expected on the basis of the corresponding 2³ S state are pointed out and discussed.     

Sandwich structures at oil-water interfaces under alkaline conditions

Equilibrium liquid crystal (LC) layer on an interface between crude oils and water was observed at high pH. This layer is composed mainly of sodium naphthenates produced in situ at the water/oil interface. Transient LC layer was also evolved at the interface of aqueous phase of sodium hydroxide solutions and oleic phase of naphthenic acid (NA) solutions as result of a chemical reaction between NaOH and NA. This chemical reaction causes transport process resulting in a disturbance of the interface. Optical observation of this interface disturbance reviled that the interface covered with LC shows considerably lower flexibility as compared to LC free interface. The LC layer eventually dissolves in the water phase at low oil-to-water ratio, while at high oil-to-water ratio it can form an equilibrium phase, which spreads spontaneously at the oil-water interface.     

Gas chromatographic analysis of bifunctional amines after derivatization with methyldichlorophosphine and sulfur

Summary A derivatization procedure for the gas chromatographic analysis of bifunctional amines likeβ-adrenergic blocking drugs is described. The method consists of a two-step reaction with methyldichlorophosphine and sulfur in presence of triethylamine to form cyclic methylphosphonothioic derivatives. The properties of these compounds are discussed and the application of the method to the quantitation of ephedrine in human body fluids is presented. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

There are uncountably many universal topological planes

We prove the existence of uncountably many nonisomorphic topological projective planes, each universal in the sense that it contains an isomorphic copy of every pseudoline arrangement.     

Bioluminescent detection of insect pheromones using an enzyme-based flow injection analysis system

The combination of flow injection analysis with chemiluminescent detection is shown to provide extremely selective and sensitive detection of insect pheromones which possess an aldehyde moiety. The flow injection analysis system provides reproducible control of both the reaction chemistry and the sample introduction process. Microliter volume samples can be precisely handled and analyzed with this experimental configuration. The detection system is based on the luciferase-catalyzed oxidation of reduced flavin mononucleotide which occurs in the presence of aldehydes with carbon backbones of between 14 and 16 carbons. A limit of detection of 3 fmol of tetradecyl aldehyde is demonstrated and the system is shown to be insensitive to the presence of various organic solvents up to concentrations of approximately 10%. The key experimental variables which control sensitive detection of pheromone at the femtomole level with be investigated and discussed.     

The annihilator of Bergman space

LetD be a bounded plane domain (with some smoothness requirements on its boundary). LetB _p(D), 1≤p<∞, be the Bergmanp-space ofD. In a previous paper we showed that the “natural projection”P, involving the Bergman kernel forD, is a bounded projection fromL _p(D) ontoB _p(D), 1<p<∞. With this we have the decompositionL _p(D)=B _p(D)⊕B _q ^⊥ (D,p ^–1+q ^–=1, 1<p< ∞. Here, we show that the annihilatorB _q ^⊥ (D) is the space of allL _p-complex derivatives of functions belonging to Sobolev space and which vanish on the boundary ofD. This extends a result of Schiffer for the casep=2. We also study certain operators onL _p(D). Especially, we show that , whereI is the identity operator and ? is an operator involving the adjoint of the Bergman kernel. Other relationships relevant toB _q ^⊥ (D) are studied.     

Vapor pressure and dissociation energy of (In2O)

The vapor pressure of pure liquid indium, and the sum of pressures of (In) and (In₂O) species over the condensed phase mixture {In} + <In₂O₃>, contained in a silica vessel, have been measured by Knudsen effusion and Langmuir free vaporization methods in the temperatue range 600 to 950°C. Mass spectrometric studies reported in the literature show that (In) and (In₂O) are the important species in the vapor phase over the {In} + <In₂O₃ >; mixture. The vapor pressure of (In₂O) corresponding to the reaction,

deduced from the present measurements is given by the equation,

The “apparent evaporation coefficient” for the condensed phase mixture is approximately 0.8. The energy for the dissociation (In₂O) molecule into atoms calculated from the above equation is D°₀ = 180.0 (± 1.0) kcal mol^?1.     

{Pt

Prolonged evacuation of [{Pt(CO)(3)}(2)](2+) (1), the first homoleptic, dinuclear, cationic platinum(I) carbonyl complex, results in reversible disproportionation. Complex 1 was formed by dissolution of PtO(2) in concentrated H(2)SO(4) under an atmosphere of CO [Eq. (a)], and completely characterized by NMR ((13)C, (195)Pt), IR, and Raman spectroscopy.