Analysis of a shielded TE011 mode composite dielectric resonator for stable frequency reference

Analysis of a TE₀₁₁ mode composite sapphire-rutile dielectric resonator has been carried out to study the temperature variation of resonance frequency, close to the Cs atomic clock hyperfine frequency of 9.192 GHz. The complementary behavior of dielectric permittivity with temperature of the composite has been exploited to obtain the desired turning point in the resonant frequency. The frequency of the composite structure is found to be independent of the shield diameter beyond four times the puck diameter.     

Spatially Directional Resorcin[4]arene Cavitand Glycoconjugates for Organic Catalysis

The synthesis of novel spatially directional multivalent resorcin[4]arene cavitand glycoconjugates (RCGs) and their ability to catalyze organic reactions is reported. The β‐d ‐glucopyranoside moieties on the upper rim of the “bowl”‐shaped resorcin[4]arene cavitand core are capable of multiple hydrogen‐bond interactions resulting in a pseudo‐cavity, which has been investigated for organic transformations in aqueous media. The RCGs have been demonstrated to catalyze thiazole formation, thiocyanation, copper(I)‐catalyzed azide alkyne cycloaddition (CuAAC), and Mannich reactions; they impart stereoselectivity in the three‐component Mannich reaction. Thermodynamic values obtained from ¹H diffusion‐ordered spectroscopy (DOSY) experiments suggest that the upper saccharide cavity of the RCG and not the resorcin[4]arene cavity is the site of the complexation event.     

Generalised Split Octonions and Their Transformation in SO(7) Symmetry

Generators of \(\operatorname{SO}(8)\) group have been described by using direct product of the Gamma matrices and the Pauli Sigma matrices. We have obtained these generators in terms of generalized split octonion also. These generators have been used to describe the rotational transformation of vectors in \(\operatorname{SO}(7)\) symmetry group.     

Application of butenonyl-C-glucosides in the synthesis of pyrazolinyl-, aminopyrimidinyl- and biphenyl methyl-��-d-C-glucopyranosides

An access to different glycohybrids involving nucleophilic addition of N- and C-nucleophiles to the butenonyl glycosides followed by cyclization and subsequent reactions is reported. In the present communication, three different prototypes, β-D-glucopyranosylmethyl pyrazolines, β-D-glucopyranosylmethyl pyrimidines and β-D-glucopyranosylmethyl biphenyls, were prepared in moderate to good yields.     

Generalization of Schwinger-Zwanziger Dyon to?Quaternion

Postulating the existence of magnetic monopole in electromagnetism and Heavisidian monopoles in gravitational interactions, a unified theory of gravi-electromagnetism has been developed on generalizing the Schwinger-Zwanziger formulation of dyon to quaternion in simple and consistent manner. Starting with the four Lorentz like forces on different charges, we have generalized the Schwinger-Zwanziger quantization parameters in order to obtain the angular momentum for unified fields of dyons and gravito-dyons (i.e. Gravi-electromagnetism). Taking the unified charge as quaternion, we have reformulated manifestly covariant and consistent theory for the dynamics of four charges namely electric, magnetic, gravitational and Heavisidian associated with gravi electromagnetism.     

Potentially useful lipase-catalysed transesterifications

Organic reactions catalysed by commercially available lipases, reported in recent years from our own laboratory and those published by others are described, confining the discussions to esteriflcation and hydrolytic reactions only. The text gives an insight into the variety of substrates accepted by these lipases and their potential applications to catalyse reactions regio-, chemo-, enantio- and diastereoselectively to produce compounds of industrial, commercial, pharmaceutical and synthetic interest.     

Theoretical and experimental studies on laser-induced transient gratings in laser dyes

Laser-induced transient grating technique has been used to measure the diffraction efficiency (η) and calculate the third-order nonlinear susceptibility (χ⁽³⁾) of some laser dyes. Theoretical simulations have been carried out on η and χ⁽³⁾ as a function of wavelength covering the spectral range corresponding to the first excited singlet state of the dyes. Theoretically simulated values have been found in agreement to those observed experimentally. The decay profiles for these dyes have been measured by using diffraction of a delayed probe laser pulse to estimate the relaxation times in the excited state.     

Synthesis of resorcin[4]arene cavitands by ring-closing metathesis

The synthesis and X-ray crystal structures of the first resorcin[4]arene cavitands by ring-closing metathesis reaction are described.     

Syntheses of calix[4]pyrroles by amberlyst-15 catalyzed cyclocondensations of pyrrole with selected ketones

A facile and efficient protocol is reported for the synthesis of calix[4]pyrroles and N-confused calix[4]pyrroles in moderate to excellent yields by reaction of dialkyl or cycloalkyl ketones with pyrrole catalyzed by reusable Amberlyst(TM)-15 under eco-friendly conditions.