Synthesis of ferrocenyl pyrazoles by the reaction of (2-formyl-1-chlorovinyl)ferrocene with hydrazines

Synthesis of ferrocenyl-substituted pyrazoles via the reaction between (2-formyl-1-chlorovinyl)ferrocene and hydrazine derivatives is described. Depending upon the substitution pattern of hydrazine, the reaction affords 1-alkyl/aryl-5-ferrocenylpyrazoles and/or 1-alkyl/aryl-3-ferrocenylpyrazoles. The reaction appears to be general for a variety of hydrazine derivatives.     

Determination of the external field amplitude and deviation parameter through expectation value based quantum optimal control of multiharmonic oscillators under linear control agents

This work focuses on the optimal control of a quantum system composed of harmonic oscillators under linear control agents (dipole function, objective operator, and the penalty operator whose expectation value is to be suppressed). The main purpose of the work is to determine the temporal external field amplitude function. Paper recalls the formulation of the optimal control equations first. Then a set of ordinary differential equations over the expectation values of certain unknown entities is constructed. These temporal differential equations have time varying coefficients unless the weight functions appearing in the cost functional are constant. Certain accompanying conditions are needed to get unique solutions. Investigations show that one half of the conditions should be given at the initial instant and the other half should be specified at the final moment. Since the differential equations contain another unknown entity, deviation parameter, solutions must satisfy an algebraic equation derived from the definition of this parameter. Results do not involve the explicit structure of the wave function and costate function. Only the external field amplitude and the deviation parameter are determined here. The evaluation of the wave function and costate function needs additional treatments to the control equations. We report certain analytical results for external field amplitude and the deviation parameter and give certain illustrative implementations to finalize the paper.     

Oxygen deficiency effects on recombination lifetime and photoluminescence characteristics of ZnO thin films; correlation with crystal structure

The photoluminescence (PL), recombination lifetime (RL), and X-ray diffraction (XRD) spectra of the samples grown at various O₂ fractions of 0.290 (Zn-rich), 0.585 (moderate), and 0.836 (O-rich) over the total pressures in the growth chamber were investigated. XRD measurements revealed that all the films show highly preferred (0002) orientation. The PL measurements exhibit different dominant emissions in the ultraviolet (UV), violet and blue regions for Zn-rich, moderate and O-rich samples, respectively. Well-known green emission and high intensity of free exciton (FX) transition has been observed in Zn-rich sample after the sample is annealed at vacuum probably due to the oxygen deficiencies. Annealing the moderate sample gives rise to the UV emission at energy of 3.263 eV similar to the observed PL emission spectrum for the Zn-rich thin film. O-rich thin film exhibits a 338 meV acceptor level above the valance band maximum, most probably related to zinc vacancy (V_Zn). Free exciton RL measurements result in 568.23, 397.65, and 797.46 ps for Zn-rich, moderate, and O-rich thin films, respectively. A good correlation was found between crystallite size and the lifetime values.     

A combined chebyshev polynomials and sumudu transform for solving the neutron transport equation (Poster Presentation)

In the present paper we present a new approximation for the one dimensional transport equation, using Chebyshev polynomials [1] combined with the Sumudu transform. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

The structure of 1-(p-fluorophenylmethyl)-2-(4-methyl-1-piperazinyl)-1H-benzimidazole hydrogen fumarate

The crystal and molecular structure of the title compound has been determined by X-ray analysis. The 1-(p-fluorophenylmethyl)-2-(4-methyl-1-piperazinyl)-1H-benzimidazole ion cocrystallizes with fumaric acid, (C₁₉H₂₂N₄F⁺·C₄H₃O ₄ ^– ), in space group P-1 with cell dimensions a = 9.938(1), b = 10.131(1), c = 12.712(1) Å, = 86.57(1), = 69.41(2), and = 67.22(2)°. The piperazine N4 atom is protonated and contacts the deprotonated O atom of the fumarate anion through a hydrogen bond. The benzimidazole ring is nearly planar and makes a dihedral angle of 111.25(12)° with the fluorophenyl ring. The piperazine ring adopts a chair conformation.     

A resource investment problem with time/resource trade-offs

In this study, we consider a Resource Investment Problem with time/resource trade-offs in project networks. We assume that there is a single renewable resource and the processing requirement of an activity can be reduced by investing extra resources. Our aim is to minimize the maximum resource usage, hence, the total amount invested for the single resource, while meeting the pre-specified deadline. We formulate the problem as a mixed integer linear model and find optimal solutions for small-sized problem instances. For large-sized problem instances, we propose a heuristic solution procedure. We develop several lower bounds and use them to evaluate the performance of our heuristic procedure. The results of our computational experiments have revealed the satisfactory behaviour of our optimality properties, lower bounds and heuristic procedure.     

The molecular aggregation of pyronin Y in natural bentonite clay suspension

The molecular aggregation and spectroscopic properties of Pyronin Y (PyY) in the suspension containing natural bentonite clay were studied using molecular absorption, steady-state and time-resolved fluorescence spectroscopy techniques. Interaction between the clay particles and the cationic dye compounds in aqueous solution resulted in significant changes in spectral properties of PyY compared to its molecular behavior in deionized water at the same concentration. These changes were due to the formation of dimer and aggregate of PyY in the clay suspension as well as the presence of the dye monomer. The H-type aggregates of PyY in the clay suspension were identified by the observation of a blue-shifted absorption band of the dye compared to that of its monomer. In spite of diluted dye concentrations, the H-aggregate of PyY in the clay suspension was formed. The intensive aggregation in the clay suspension attributed to the localized high dye concentration on the negatively charged clay surfaces. Adsorption sites of PyY on the clay particles were discussed by deconvulated absorption and excitation spectra. Fluorescence spectroscopy studies revealed that the fluorescence intensity of PyY in the clay suspension is decreased by H-aggregates drastically. Moreover, the presence of H-aggregates in the clay suspension resulted in the decrease of fluorescence lifetime and quantum yield of PyY compared to those in deionized water.