Steady-state electrode potentials of solid-electrolyte cells in reducing chemically nonequilibrium gas mixtures

The paper studies the steady-state potential response of the electrodes of solid-electrolyte cells with ZrO₂ + 9 mol % Y₂O₃ in reducing nonequilibrium gas mixtures of N₂ + H₂ + H₂O + O₂ with a low content of O₂ and in the mixtures of CH₄ + CO₂ + CO with a low content of CO, in the temperature range of 450–900°C. The dependences of potentials of the electrodes of different materials on the temperature and composition of gas mixtures were measured. The results were compared with the values of potentials in corresponding mixtures after chemical equilibrium was established. Characteristic temperature were determined, above which the electrodes feature a potential corresponding to chemically equilibrium mixtures.     

Displacement reactions of covalently attached organosilicon monolayers on Si

The covalently attached monolayers of alkylsilanes (R(CH(3))(2)SiX) on Si undergo complete displacement by the solutions of different organosilanes (R'(CH(3))(2)SiX). By varying the reaction time, the degree of displacement can be controlled offering a convenient method for the preparation of surfaces with mixed functionalities (R and R').     

Pairing correlations around scission

To describe pairing correlations in a fissioning system one commonly projects the BCS wave function separately onto good particle numbers in each fragment in the exit channel, but only onto the total number of particles in the parent system. We propose to interpolate between these limiting situations by the generator-coordinate method with the particle-number difference between the nascent fragments as the generator coordinate. Model calculations are presented for the Hill–Wheeler-box potential with a δ-function diaphragm to mimic scission.     

Potentials of Oxide Electrodes in Cells with a Zirconium Dioxide-Based Electrolyte in Mixtures of Nitrogen,Oxygen, Carbon Dioxide,and Carbon Monoxide Gases

Measurements of steady-state potentials of various electrodes made of oxide compositions are performed in cells containing electrolyte ZrO₂ + 10 mol % Y₂O₃ at a temperature of 773 K in nonequilibrium gas mixtures N₂ + O₂ + 20 vol % CO₂ + CO, with variable CO (0.1–5 vol %) and O₂ (0.5–10 vol %) contents. After adding CO into a gas phase, potentials of all electrodes shift, to one degree or another. The shift is substantially affected by the O₂ content. The electrochemical systems under study are of some interest for analyzing partial pressures of CO in gas mixtures. The discovered effect must be taken into account when employing such electrodes for the determination of partial concentrations of other components of a gas mixture, for example, oxygen.     

Hydrolytic stability of organic monolayers supported on TiO2 and ZrO2

The hydrolytic stability of C18 monolayers supported on TiO2 and ZrO2 was studied. Three types of monolayers were prepared from the following octadecyl modifiers: (1) octadecyldimethylchlorosilane (C18H37Si(CH3)2Cl); (2) octadecylsilane (C18H37SiH3); and (3) octadecylphosphonic acid (C18H37P(O)(OH)2). The hydrolysis of the surfaces prepared was studied under static conditions at 25 and 65 degrees C at pH 1-10. On the basis of the loss of grafted material, the stability of the monolayers fall in the following range: C18H37P(O)(OH)2 > or = C18H37SiH3 > C18H37Si(CH3)2Cl. At 25 degrees C, monolayers from C18H37P(O)(OH)2 showed only approximately 2-5% loss in grafting density after one week at pH 1-10. The high stability of these monolayers was explained because of the strong interactions of the phosphonic acids with the substrates. Monolayers from C18H37Si(CH3)2Cl showed poor hydrolytic stability at any pH, which was explained because of the low stability of Ti-O-Si and Zr-O-Si bonds. Unlike monofunctional silanes, trifunctional silane (C18H37SiH3) yielded surfaces that showed good hydrolytic stability. This suggests that the stability of the monolayers from trifunctional silanes is primarily due to "horizontal" bonding (Si-O-Si or Si-OH...HO-Si) rather than due to bondingwith the matrix (M-O-Si). At 65 degrees C, all C18 surfaces become more susceptible to hydrolysis; however, the trend observed for 25 degrees C remained unchanged. Low-temperature nitrogen adsorption was used to study the adsorption properties of the monolayers as a function of their grafting density. The energy of adsorption interactions showed a significant increase as the grafting density of the monolayers decreased. The order of the alkyl groups in the monolayers, as assessed from CH2 stretching, decreased as the grafting density of the monolayers decreased.     

Methods for finding steady-state solutions of mathematical models for chemico-technological schemes

Gradient and Newton methods are suggested for searching for steady-state solutions of chemico-technological schemes to obtain synthetic fuels.

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Synthesis and the crystal structures of N-(2-nitroxyethyl)isonicotinamide and its complexes with PdCl2 and PtCl2 as potential antitumor medicines

Previously unknown N-(2-nitroxyethyl)isonicotinamide was synthesized by the reaction of isonicotinoyl chloride with 2-nitroxyethylamine and was used as a ligand in the reactions with PdCl₂ and PtCl₂ to prepare new complexes, viz., trans-bis[(2-nitroxyethyl)isonicotinamide-N]dichloropalladium(ii) and cis-bis[(2-nitroxyethyl)isonicotinamide-N]dichloroplatinum(ii), respectively. The structures of the ligand and the resulting complexes were established by X-ray diffraction analysis.     

Deuteron ground state properties and low energy P-N scattering 1 S 0 and 3 S 1–3 D 1 channels

Deuteron properties and P-N elastic scattering in ¹ S ₀ and ³ S ₁–³ D ₁ channels are described within the framework of a model containing non-local interactions that take into account quark exchange processes. Comparisons with other theoretical results are also made. Received: 1 February 1999     

New hydrogen-like states due to Ni in ZnS

In addition to the narrow zero-phonon line at the photoionisation band edge at 2.4377 eV reported in absorption measurements of Ni-doped ZnS, another two sharp lines at 2.4268 and 2.4325 eV in the electroabsorption spectrum have been detected for the first time. At the bottom of the photoinization band a new structure has also been observed, which consists of a zero-phonon line at 3.3897 eV and its LO-phonon sidebands. The zero-phonon lines in the photoionization band are attributed to transitions into hydrogen-like states of a hole, loosely bound to a Ni¹⁺ ion which is either in the ground ${}^2\text{T}{}_2$ or high-lying excited ${}^2\text{E}$ states.