1-Soliton solution of the coupled KdV equation and Gear–Grimshaw model

This paper carries out the integration of the coupled KdV equation with power law nonlinearity. The solitary wave ansatz is used to carry out the integration. The domain restrictions of the coefficients of nonlinear and dispersion terms fall out. The results are then supplemented by numerical simulations.     

The Two-Nucleon Stripping Process with Skyrme Type Potential

Theory of two-nucleon stripping reactions is reconsidered. The nucleon-nucleon interactions are taken as Skyrme type potentials. Differential cross-sections for two-nucleon stripping reactions are calculated using DWBA approximation with different Skyrme type potentials of different parameters. The angular distributions for different two-nucleon stripping reactions (t, p) with incident triton on the different targets of ³¹P, ⁴⁰Ca, ⁹⁶Zr, ¹¹⁸Sn and ²⁰⁶Pb are calculated giving good agreement with the experimental data. Better values are extracted for the spectroscopic factors.     

A study of the (α, t) reaction on 19F, 27Al, 51V and 59Co

The angular distributions of tritons from the (α, t) reaction on ¹⁹F, ²⁷Al, ⁵¹V and ⁵⁹Co nuclei corresponding to the (0⁺) ground states and (2⁺) excited states in the final nuclei have been measured in the angular range between 15° and 170° at α-particle energies of 25 MeV. For reactions on ²⁷Al and ⁵¹V nuclei, the differential excitation functions have also been obtained at different angles of outgoing tritons at E_α from 20 to 25 MeV. The experimental angular distributions are analysed by the DWBA approximation on the assumption of a nucleon stripping mechanism. The analyses of the present results and the data obtained earlier for the (α, t) reaction on the 1 p shell nuclei, A ? 30, reveal that the distinguishing feature of the reaction under study is the presence of backward angle peaks in the reaction cross section, which appear to be associated with exchange processes. For the (α, t) reaction on the heavier nuclei (A > 30), the dominant mechanism is nucleon stripping.     

On Dumont's polynomials

We derive two generating functions and an explicit formula for the polynomials {H_n(x)} studied by Dumont.     

Versatile and facile synthesis of diverse semisynthetic tetracycline derivatives via Pd-catalyzed reactions

A diverse collection of tetracycline derivatives has been synthesized utilizing Heck, Suzuki, and other palladium-coupling reactions via tetracycline arenediazonium and iodoarene salts. Large numbers of tetracyclines are now possible via these reactions, including numerous upper periphery derivatives of doxycycline, minocycline, sancycline, and methacycline modified at positions C7, C9, and C6-C13 on the tetracycline naphthacene ring. Application of palladium-coupling reactions to the tetracyclines has yielded new tetracycline classes with differing structural attributes, greatly increasing the structural diversity of this family of antibiotics, one of the last of the early antibiotic families to be expanded by organic and medicinal chemistry.     

Isolation and structure determination of a benzofuran and a bis-nor-isoprenoid from Aspergillus niger grown on the water soluble fraction of Morinda citrifolia Linn. leaves

The leaves of Morinda citrifolia, Linn. afforded a new benzofuran and a bis-nor-isoprenoid, blumenol C, hitherto unreported from this source. The structures of these have been elucidated as 5-benzofuran carboxylic acid-6-formyl methyl ester (1) and 4-(3'(R)-hydroxybutyl)-3,5,5, trimethyl-cyclohex-2-en-1-one (2) respectively through spectroscopic studies. The NMR data (including 1D, 2D techniques) and stereochemistry at C-3' of Compound 2 is also being reported for the first time.     

Determination of the Effect of Temperature on the Concentration of keto form of D-Fructose by FT-IR Spectroscopy

Abstract

FT-IR spectroscopy has been employed in the detection of the carbonyl absorption band centered at 1728 cm^?1 and assigned to the open form of D-fructose in deuterium oxide or water. Changes in the intensity of the band at 1728 cm^?1 allowed the monitoring of the concentration of the open form of the keto sugar D-fructose at different temperatures and pHs. The concentration of the open form was observed to increase with increasing temperature and was an order of magnitude higher at 80 °C compared to 30 °C. The buildup of the open form was found to be extremely rapid. The new equilibrium can be reversed with decreasing temperature with a slight hysteresis. This work demonstrates the potential of applying FT-IR spectroscopy in studying the effect of environmental factors on the level of the open chain form of sugars.     

Threshold reduction of stimulated Brillouin scattering in photonic crystal fiber

A simple configuration for the reduction of stimulated Brillouin scattering threshold in photonic crystal fiber is presented. The threshold reduction is contributed by the bidirectional pumping scheme through the reflection of transmitted Brillouin pump back to the gain medium. The pump recycling scheme has greatly reduced the Brillouin threshold of a 200-m long of photonic crystal fiber from 50 to 30 mW of Brillouin pump power.     

Towards understanding the critical heat flux for industrial applications

Understanding CHF is of an upmost importance in many industries, especially in the design and operation of boilers, nuclear power plants, cryogenic systems, etc. Due to safety issues related to the nuclear power plants, and the adaptation of CHF as the limiting criterion of power generation, it is important to understand the mechanisms of CHF relevant to nuclear systems operation. Moreover, CHF is expected to occur during transients than steady-state conditions. Therefore, knowledge of transient CHF is of great importance for the safety evaluation of nuclear reactors under transient condition. In this paper, the existing CHF experimental and modeling studies are discussed in order to understand the phenomena leading to CHF. Also, the effect of transient conditions on CHF for nuclear fuels has been evaluated.