The conventional solid-state reaction method was utilized to prepare a series of superconducting samples of the nominal composition Bi2-xPb0.3WxSr2Ca2Cu3O10+d with 0≤x≤0.5 of 50 nm particle size of tungsten sintered at 8500C for 140h in air . The influence of substitution with W NPs at bismuth (Bi) sites was characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM) and dc electrical resistivity. Room temperature X-ray diffraction analysis revealed that there exists two phases, i.e. Bi-(2223) and Bi-(2212), in addition to the impurity phases of (SrCa) 2Cu2O3, Sr2Ca2Cu7Oδ, Ca2PbO4, CaO, and WO. It was found that the crystallographic structure of all samples was orthorhombic. Lattice parameter values and the volume fraction of the (2223)-phase of the prepared samples were also calculated. The superconductivity transition temperature (Tc) for samples subjected to substitution with W NPs was found to be higher than that for the pure sample. The optimal value of W NPs content in (Bi, Pb)-2223 system was found to be at x=0.3.
The new compounds of pyrazolines were synthesized from the reaction of different acid hydrazide with ethylacetoacetate and ethanol under reflux. These compounds were obtained from many sequence reactions. The 4-acetyl-5-methyl-2,4-dihydro-3H-pyrazol-3-one compounds synthesized from the reaction of 5-methyl-2,4-dihydro-3H-pyrazol-3-one with acetyl chloride in calcium hydroxide and 1,4-dioxane. Finaly, Schiff bases were prepared via condensation reaction of products of mono- and tri ketone derivatives[IV]a, b with phenyl hydrazines as presented in (Scheme 1, 2). The synthesized compounds were identification by using FTIR, NMR and Mass spectroscopy (of some of them).
In the present work, HgBa2Can-1CunO2n+2+δ superconducting thin films with (100) nm thickness were (n=1, 2 and 3) prepared by Pulsed Laser Deposition technique on glass substrate at R.T (300) K, have been synthesize. The effect of Cu content on the structural, surface morphology, optical and electrical properties of HgBa2Can-1CunO2n+2+δ films were investigated and analyzed. The results of XRD analysis show that all samples are polycrystalline structure with orthorhombic phase, the change of Cu concentration in samples produce changes in the mass density, lattice parameter and the ratio (c/a). AFM techniques were used to examine the surface morphology of HgBa2Can-1CunO2n+2+δ superconducting films, the study showed the values of surface rou
... Show MoreDensity Functional Theory (DFT) with B3LYP hybrid exchange-correlation functional and 3-21G basis set and semi-empirical methods (PM3) were used to calculate the energies (total energy, binding energy (Eb), molecular orbital energy (EHOMO-ELUMO), heat of formation (?Hf)) and vibrational spectra for some Tellurium (IV) compounds containing cycloctadienyl group which can use as ligands with some transition metals or essential metals of periodic table at optimized geometrical structures.
This article includes designed and synthesized for bent-shaped liquid crystal molecules starting from 5,5-diethylpyrimidine-2,4,6(1H,3H,5H)-trione and two moles of chloroacetylchloride in N, N-dimethyl formamide (DMF) and triethylamine (TEA) to product compound [I] ,then reacted the later compound with two moles of 4-hydroxybenzonitrile to yield nitrile compound [II]. Likewise, reaction 5,5-diethylpyrimidine-2,4,6(1H,3H,5H)-trione and two moles of ethylchloroacetate with fused sodium acetate in ethanol to create an ester compound [III], and then the later compound was reacted with two moles of hydrazine hydrate in ethanol to obtained hydrazide acid compound [IV]. After that, the compound [IV] reacted with two moles of ethyl acetoacetate in
... Show MoreIn an attempt to shed a light on the possible relationship between lipid peroxidation and some antioxidant. The effect of vitamine E (as a potent antioxidant free radical scavenger) on the serum levels of Total cholesterol (TC) and Triacylglycerols (TG) was studied and the lipid peroxidation marker (MDA) was measured. The study includes (50) healthy donors from males and females who had given vitamine E at a rate of (400IU) daily for one month and were divided into two groups. 1. Group (A) : included (25) males donors (20-40) years old, before and after giving vitamine E. 2. Group (B) : included (25) females donors (20-40) years old , before and af
... Show MoreNew metal complexes of some transition metal ions [Fe(III) , Co(II) , Ni(II) and Cu(II)] of two previously prepared ligands HLI=(P-methyl anilino)- P-methoxy phenyl acetonitrile and HLII =(P-methoxy anilino)-P- methoxy phenyl acetonitrile were synthesized. The two ligands were prepared by Strecker's procedure which included the reaction of Pmethoxybenzaldehyde with p-toluidine and P-anisidine respectively. The structures of the new metal complexes were characterized by atomic absorption , i.r and U.V.-visible spectra . Magnetic susceptibilities and conductivity measurements in DMF of metal complexes were also studied. These ligands coordinate as abidentate molecules through nitrogen atoms of ï¡amino group and nitrile group except the
... Show MoreElectron transfer (ET) reactions represent an elementary chemical process which occurs in a large variety of molecules, ranging from small ion pairs up to large biological system. A theoretical study of photo – induced electron transfer between Ruthenium (II) tirs -( 2,2 ï‚¢- bipyrdine ) Ru(bpy)  2 3 and Methyl Viologen MV2+ in a variety of Solvents at room temperature is presented . This study is based on an optical activation by the absorption of light .The Solvent is described by a dielectric continuum model, and the transferring is represented by a quantum mechanical wave function . In this application, the reorganization energy ï¬ , the driving free energy ï¯ Gï
... Show MoreThe purpose of the current work was to evaluate the effect of Radiation of Gamma on the superconducting characteristics of the compound PbBr2Ca1.9Sb0.1Cu3O8+δ utilizing a 137Cs source at doses of 10, 15, and 20MRad. Solid state reaction technology was used to prepare the samples. Before and after irradiation, X-ray diffraction (XRD) and superconductor properties were examined. Results indicated that the tetragonal structure of our chemical corresponds to the Pb-1223 phase with an increase in the ratio c/a as a result of gamma irradiation. (Tc (onset) ) and on set temperature Tc (offset)) were also dropping from 113 to the 85.6 K and 129.5 to 97 K, respectively, for a transition temperatu
The reaction of some new Schiff bases ( 2-[(2-Amino – ethylimino)-methyl]-R , 2-({2-[(R-benzylidene)-amino]-ethylimino}-methyl)-R with Benzoyl chloride or Acetyl chloride were carried out. Subsequent reactions of these products N-(2-Amino-ethyl)-N-[Chloro-(R) –methyl]-benzamide or N-(2-{?-[chloro-(R) –methyl]-amino}-ethyl)-N-[chloro-(R) –methyl]- benzamide with thiourea afforded thioureas compounds. The synthesized compounds were confirmed by their IR,UV,spectra and C.H.N. analysis.