Electrical transport mechanism in Al/V2O5/Al microdevices

The current-voltage characteristics of metal-insulator-metal microdevices fabricated with electron-beam evaporated vanadium pentoxide films have been studied in order to understand the electrical transport mechanism in these films. The dependence of transport properties on various factors such as film thickness, substrate temperature, and applied field, has been established. The results revealed that the electrical transport follows a Schottky-type mechanism at lower electrical fields and a Poole-Frenkel-type at higher electrical fields than 2×10⁶ V/m.     

Contributions to the investigation of inorganic non-stoichiometric compounds. XXXI. A New NbOx Phase with ß-ZrNb24O62 structure

Chemical transport reactions with HgCl₂ as transport agent were used to prepare crystals (l = 1–2 mm) of the phases Nb₂₂O₅₄, Nb₄₇O₁₁₆, Nb₂₅O₆₂ and Nb₅₃O₁₃₂. Due to the high temperature applied (T ≈ 1250 to 1280°C) a new NbO_x phase was formed. Without a transport agent the temperature had to be even higher (≈ 1350°C). The complicated block structure of the new phase corresponding to the ideal composition Nb₂₅O₆₂ was revealed by HRTEM. The structure visible by this method remained unchanged on oxidation to Nb₂O₅.     

Solutions of gravitational field equations

In this paper we use iterative methods to generate series solutions of the gravitational field equations in a cosmological model with heat flow.     

The adsorption of CO on Cu(110)

The adsorption of CO on Cu(110) has been studied by LEED, surface potentials and infrared spectroscopy. With increasing surface coverage the s.p. passes through a maximum value of 0.29 V and than falls to 0.17 V at saturation. The heat of adsorption is nearly constant (~55 kJ mol^?1) up to the maximum s.p. but then falls rapidly. A ( 2× 1) structure is formed near the s.p. maximum, followed by a structure which is compressed in the [11?0] direction and poorly ordered in the [001] direction but tending towards c(1.3 × 2). At low coverage two infrared bands appear at 2088 and 2104 cm^?1; their relative intensity is similar at 77, 195 and 295 K. As the coverage increases, the bands shift in frequency and merge into a single band at 2094 cm^?1. The origin of the two bands is discussed in relation to the overlayer structure. Strong interaction between CO molecules is shown by the spectra of mixtures of ¹³CO and ¹²CO.     

Effect of Micelles on kinetics and mechanism of the oxidation of Serine by acid Permanganate

The oxidation of serine (HORCO₂H) by acid permanganate was investigated both in the absence and presence of sodium dodecyl sulfate (SDS). It has been observed that the presence of surfactant enhanced the reaction rate. The reaction is first order with respect to [Serine] and [MnO₄^?]. The reaction is retarded by the hydrogen ion in the absence of SDS but catalyzed in the presence of SDS. The overall rate expression for the reduction of Mn(VII) may be written as In the presence of SDS of the rate law is The reaction appears to involve a parallel consecutive reaction mechanism in which Mn(IV) appears as the reaction intermediate. ??′_4f signifies the rate constant for the reaction path leading to the formation of Mn(IV) from Mn(VII) as reaction intermediate, whereas ??′_2f signifies the rate constant for the reaction path leading to the reduction of Mn(VII) to Mn(II) without prior formation of Mn(IV). A mechanism satisfying the various kinetic parameters has been proposed.     

2-Hydroxy-1-acetonaphthoneoxime as analytical reagent

2-Hydroxy-1-acetonaphthoneoxime has now been proposed as a new reagent for the gravimetric determination of copper. Copper in the range 4·0 to 40·0 mg can be accurately determined by this procedure. The interference of the elements usually associated in its alloys and ores is also studied. The method is applied in the analysis of brass and chalcopyrite.     

Vibration analysis of bi-layered FGM cylindrical shells

In the present study, a vibration frequency analysis of a bi-layered cylindrical shell composed of two independent functionally graded layers is presented. The thickness of the shell layers is assumed to be equal and constant. Material properties of the constituents of bi-layered functionally graded cylindrical shell are assumed to vary smoothly and continuously through the thickness of the layers of the shell and are controlled by volume fraction power law distribution. The expressions for strain–displacement and curvature–displacement relationships are utilized from Love’s first approximation linear thin shell theory. The versatile Rayleigh–Ritz approach is employed to formulate the frequency equations in the form of eigenvalue problem. Influence of material distribution in the two functionally graded layers of the cylindrical shells is investigated on shell natural frequencies for various shell parameters with simply supported end conditions. To check the validity, accuracy and efficiency of the present methodology, results obtained are compared with those available in the literature.