Effects of the Three-Nucleon Forces from Different Meson Exchanges on the Triton Binding Energy

Effects of the three-nucleon forces on the triton binding energy are investigated using different models for which the xN scattering amplitudes for the off-mass-shell pions are extrapolated from the on-mass-shell data. In the independent model potential, the threenucleon forces are constructed using the chiral symmetry through partial conservation of the axial current vectors and current algebra. On the other hand, the three-nucleon forces in the dependent model potential are derived from an effective Lagrangian which is constrained by chiral and gauge symmetry. The effect of the long range 2π and the repulsive ap-exchange three-nucleon forces on the triton binding energy are investigated. The bound state triton binding energies are then calculated by solving the Faddeev equations with a Hamiltonian including the three-nucleon forces, using different nucleon-nucleon interactions. The pionic form factors are considered with different sets of the form factor cutoff,parameter Λ. The 2π-exchange forces with S- and P-wave amplitudes are found to overbind the triton binding energy by about 0.4～Y 1.6 MeV. However, xp-exchange forces are found to reduce the 2π exchange forces by about 18% of its contribution, to the triton binding energy.     

Natural product propolis: chemical composition

The chemical composition of propolis from East Mediterranean (Hatay, Adana and Mersin) was studied in order to determine the major compounds by using GC-MS. In this study, the ethanolic extract of propolis prepared by mixing 1900mL 70% ethanol and 100g propolis was used. Chemical analysis of propolis extracts indicated that the propolis samples had high concentrations of the aromatic acids, esters and other derivatives which are responsible for the anti-bacterial, anti-fungal, anti-viral, anti-inflammatory and anti-cancer properties of propolis such as benzyl cinnamate, methyl cinnamate, caffeic acid, cinnamyl cinnamate and cinnamoylglcine besides the most common compounds as fatty acid, terpenoids, esters, alcohols hydrocarbons and aromatic acids.     

Synthesis,thermal reactivity,and kinetics of stabilized phosphorus ylides,part 2: [(Arylcarbamoyl)(cyano)methylene]triphenylphosphoranes and their thiocarbamoyl analogues

A series of five cyano(arylcarbamoyl) phosphorus ylides 2 and five cyano(arylthiocarbamoyl) phosphorus ylides 3 are prepared and fully characterized. Pyrolytic reaction products of a representative example of each type obtained by flash vacuum pyrolysis technique show that they undergo thermal extrusion of Ph₃PO or Ph₃PS. Kinetic study of the gas‐phase pyrolysis of each ylide by static method shows that these reactions are unimolecular and first order with no significant substituent effect, but the thiocarbamoyl ylides 3 react 40–65 times more rapidly than their carbamoyl analogues 2 . © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 496–502, 2006     

Coupled bending and torsional vibration of a beam with in-span and tip attachments

In this paper, the coupled flexural-torsional free and forced vibrations of a beam with tip and/or in-span attachments are studied. First, a mathematical model is established, which consists of a beam with several tip attachments, i.e, a tip mass of non-negligible dimensions, a linear spring grounding the tip mass, and a torsional spring connected at the end of the beam. The modal functions of this model and the orthogonality condition among them are derived. For the purpose of verification the properties of the tip attachments are changed, and the numerical results obtained are compared with those given in the relevant literature. Effects of tip mass and distributed mass in-span on natural frequencies and modes are investigated for two cantilever beams with different cross sections. An application of the orthogonality condition in the case of a beam with tip mass is also presented for a forced vibration example.     

Synthesis and non-aqueous medium titrations of some new 4-benzylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-one derivatives

The synthesis of 3-alkyl(aryl)-4-(3-ethoxy-4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones 3 from the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones 2 with 3-ethoxy-4-hydroxybenzaldehyde is described.The acetylation and methylation reactions of the compounds 3 giving compounds of type 4 and 5, respectively, were investigated. The newly synthesized compounds were characterized using elemental analyses and IR, (1)H-NMR, (13)C-NMR and UV spectral data.In addition, to investigate the effects of solvents and molecular structure upon acidity,compounds 3 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide). The half-neutralization potential values and the corresponding pKa values were determined for all cases.     

Graphical representation of reflection from single and double coating systems on metallic substrate

In the present work a new graphical method is described to represent the resultant of the multiply reflected waves from coating systems consisting of single and double layers on metallic substrate, taking into account the optical phase properties of the films.     

Synthesis of Unbranched 4-Alkylbenzaldehydes

The preparation of unbranched 4-alkylbenzaldehydes free of positional and branched-chain isomers by different methods is described. A one-step preparation of the aldehydes is reported which involves the -direct hydrogenation of a Friedel Craft's complex in the presence of Pd/C catalyst.     

Stereospecific synthesis of methyl D,L-hex-2-ulopyranosides from furan compounds

2-Benzyloxymethyl-5-hydroxymethylfuran was converted, according to the known method, into methyl 1-O-benzyl-3,4-dideoxy-d,l-hex-3-en-2-ulopyranos-5-ulose. Reduction of the latter and hydroxylation or epoxidation, followed by the oxirane ring opening, afforded the title compounds with α-sorbo-, β-fructo-, α-tagato- and α-pisco- configuration. The steric course of reduction, hydroxylation and epoxidation reactions were examined.     

Sensitivity of the three-body calculations to different effects

The bound state of few-body systems in light nuclei is studied as a three-body problem. The three-body problem is solved following the different approaches of the Faddeev formalism as well as the unitary pole approximation. Separable approximations are introduced to reduce the three-body problem to a set of coupled integral equations. Numerical calculations are carried out for the resulting integral equations and the separable expansion. In the present work, we calculate the ground-state binding energy of the bound three-nucleon system³H. The main interest of the present work is to investigate the sensitivity of the three-body binding energy to different effects in the problem. For this reason, we study the dependence of the three-body binding energy of different forms of local and separable two-body potentials, on the effective range of the two-body potentials, and on the percent of theD state in the deuteron wave function. Also, we test the sensitivity of the three-body binding energy to the considered number of terms from the separable expansion.     

Semiempirical calculations of ground state properties and rotational barriers in conjugated ethylenes

Ground state properties of methyl-2-carbomethoxy-3-dimethylaminoacrylate 4, and methyl-2-carbomethoxy-3-(1-aziridino) acrylate 5 were calculated by semiempirical methods and found to be in good agreement with the experiment. Barriers to rotation about the CC double bond and the C-N single bond were also calculated, allowing for structure relaxation in the transition state. A comparison of the calculated and experimental barriers to rotation shows good agreement for the rotation about the C-N bond and poor agreement for the rotation about the CC bond. This discrepancy is explained in terms of solvent stabilization of the polar transition state.