Solvent effects on oxygen atom transfer reaction between manganese(V)-oxo corrole and alkene

Pseudo-first order reaction rate constants of 5,10,15-tris（pentafluorophenyl）corrole Mn（V）-oxo (F₁₅CMn（V）-oxo),5,15-bis（pentafluorophenyl）-10-（phenyl）corrole Mn（V）-oxo(F₁₀CMn（V）-oxo),5,15- bis（phenyl）-10-（pentafluorophenyl）corrole Mn（V）-oxo（F₅CMn（V）-oxo） and 5,10,15-tris（phenyl）corrole Mn（V）-oxo（F₀CMn（V）-oxo） with a series of alkene substrates in different solvents were determined by UV-vis spectroscopy.The results indicated that the oxygen atom transfer pathway between Mn（V）-oxo corrole and alkene is solvent-dependent.     

Temporal investigation of acoustic wave pressure spectrum of high repetition rate TEA-CO2 lasers by using a three-dimensional mathematical model

The production of acoustic wave is one of the most important factors on the action of High Repetition Rate TEA-CO₂ lasers. In this paper a three-dimensional mathematical modeling has been considered for investigation of temporal and spatial variations of acoustic waves in the laser cavity and its effect on the output of HRR lasers. By calculation of equations obtained from this model and plotting the pressure spectrum in different states, the effect of electrodes dimensions, cavity dimensions, gas flow velocity and repetition rate of laser in different times have been acquired. At last, optimum conditions for performance of laser action and having a good output have been arrived.     

β-Octafluorinated tetrakis(ethoxycarbonyl)porphyrin

Tetrakis(alloxycarbonyl)porphyrin and its β-octafluoro-substituted derivatives were synthesized via Lindsey method and transformed to their zinc complexes.Single crystal X-ray structures of corresponding Zn(Ⅱ) porphyrins revealed that β-octafluorination will give more compactness of porphyrin moieties in the crystal structure owing to the hydrogen bonding interactions involving β-fluorine atoms.An unusual six-coordinated Zn(Ⅱ) was found via intramolecular coordination of oxygen atom of meso-substituents with central Zn(Ⅱ).     

Effect of acoustic waves on the repetition frequency of high repetition rate TEA-CO2 lasers and calculating optimization condition

The gas channel of a pulse periodic TEA-CO₂ laser is considered as an acoustic resonator. In this paper, a three-dimensional mathematical modeling has been considered for describe of laser action. By calculating of the equations obtained from this model, the effects of cavity dimensions, Mach number and repetition frequency of laser on the acoustic wave spectrum have been investigated. At last optimum conditions for performance of laser operation has been arrived.     

Dynamics of Entropy and Nonclassicality Features of the Interaction between a ◊-type Four-Level Atom and a Single-Mode Field in the Presence of Intensity-Dependent Coupling and Kerr Nonlinearity

The interaction between a ◊-type four-level atom and a single-mode field in the presence of Kerr medium with intensity-dependent coupling involving multi-photon processes has been studied. Using the generalized (nonlinear) Jaynes-Cummings model, the exact analytical solution of the wave function for the considered system under particular condition, has been obtained when the atom is initially excited to the topmost level and the field is in a coherent state. Some physical properties of the atom-field entangled state such as linear entropy showing the entanglement degree, Mandel parameter, mean photon number and normal squeezing of the resultant state have been calculated. The effects of Kerr medium, detuning and the intensity-dependent coupling on the temporal behavior of the latter mentioned nonclassical properties have been investigated. It is shown that by appropriately choosing the evolved parameters in the interaction process, each of the above nonclassicality features, which are of special interest in quantum optics as well as quantum information processing, can be revealed.     

Preparation,heat treatment and photoluminescence properties of V-doped ZnO–SiO2–B2O3 glasses

Four glasses in ZnO–SiO₂–B₂O₃ ternary system were prepared by the melt quenching method with the objective of optimizing sub-nanosecond emission over the UV region of zinc borosilicate glasses used in superfast scintillators. The effect of vanadium addition and heat treatment on phase formation, microstructure and photoluminescence properties of the glasses was characterized by means of DTA, XRD, SEM and fluorescence spectrophotometer. Vanadium contributed to the near-band-edge emission in two ways, by introducing donor levels in the energy band of ZnO particles and by facilitating the precipitation of ZnO and willemite crystals. Furthermore, nucleation of willemite and zinc oxide phases, which are both the origins of the intense emission bands in the UV region, was facilitated with increasing either the time or temperature of heat treatments. Photoluminescence spectra showed the elimination of the visible emission band which is favorable in scintillating glasses.     

Surface crystallization of rare-earth aluminosilicate glasses

Surface crystallization in a rare-earth aluminosilicate glass (Nd₂O₃–Al₂O₃–SiO₂–TiO₂) was studied using an isothermal method and the crystal growth rate of the glasses was evaluated as a function of the composition. For measuring the surface crystal growth rate, two different methods: measurement of the crystal layer in the longitudinal and lateral growth direction. It was found that crystallization proceeded by surface crystallization only and TiO₂ did not act as a nucleating agent. The growth rate was strongly dependent on the viscosity of glass and agreed with prediction from the Preston model using the known viscosity and melting temperature. As the Si/Nd and Si/Al ratios decreased, the crystal growth rate increased. TiO₂ and Nd₂O₃ played the role of network modifier, which decreased the viscosity of the glass, facilitating crystallization of the rare-earth aluminosilicate glass.     

Unexpected one-pot synthesis of A3-type unsymmetrical porphyrin

The first direct synthesis of A₃-type unsymmetrical porphyrin is achieved via conventional pyrrole–aldehyde condensation in a one-pot procedure in an appreciable yield. Generalization of this approach to a variety of other aldehydes revealed that it is advantageous for highly electron-rich aldehydes giving unsymmetrical porphyrin, while electron-poor aldehydes even failed to cyclize under the same experimental conditions.