Polarization properties of multimode internal mirror He-Ne lasers

The polarization behaviour of internal mirror multimode He-Ne lasers oscillating at 632.8 nm has been experimentally studied. It has been found that phase anisotropy of the cavity plays a dominant role in determining this behavior and fixing polarization configuration of the modes.     

Theorems and applications of two-dimensional Laplace transforms

The object of this paper is to establish two new formulas for calculating Laplace tranform pairs of two dimensions from known one-dimensional Laplace transforms. Two boundary-value problems are also solved by using double Laplace transforms.Published in Ukrainskii Matematicheskii Zhurnal, Vol. 39, No. 3, pp. 374–377, May–June, 1987.     

Synthesis and biological activity of peptide derivatives of iodoquinazolinones/nitroimidazoles

Two substituted quinazolinyl/imidazolyl-salicylic acids 5, 6 were synthesized by the reaction of 6-iodo-2-methylbenzoxazin-4-one/5-nitroimidazole with 5-aminosalicylic acid (5-ASA). Coupling of compounds 5 and 6 with different amino acid ester hydrochlorides, dipeptide and tripeptide methyl esters yielded novel quinazolino/imidazolopeptide derivatives 5a-f and 6a-g. The chemical structures of all newly synthesized compounds were confirmed by means of FT-IR, (1)H- and (13)C-NMR, MSand elemental analysis. Selected peptide ester derivatives were further hydrolyzed by using lithium hydroxide (LiOH) to afford the corresponding acid derivatives 5ba-da and 6e(a)-g(a). All peptide derivatives were assayed for antimicrobial and anthelmintic activities against eight pathogenic microbes and three earthworm species. Among the tested compounds, 5e,5d, 6e and their hydrolyzed analogs 5d(a) and 6e(a) exhibited higher antimicrobial activity against Pseudomonas aeruginosa, Klebsiella pneumoniae and Candida albicans, and 5(a),6g and 6g(a) displayed better antifungal activity against the dermatophytes Trichophyton mentagrophytes and Microsporum audouinii. Moreover, 6f and its hydrolyzed derivative6f(a) showed good anthelmintic activity against Megascoplex konkanensis, Pontoscotex corethruses and Eudrilus eugeniea at dose of 2 mg mL(-1).     

An alternate approach to solve two-level hierarchical time minimization transportation problem

This paper discusses a two-level hierarchical time minimization transportation problem, which is an important class of transportation problems arising in industries. This problem has been studied by various researchers (Sharma et al. in Eur J Oper Res 246:700–707, 2015; Sonia and Puri in TOP 12(2):301–330, 2004; Xie et al. in Comput Oper Res 86:124–139, 2017) and therefore, a number of polynomial time iterative algorithms are available to find its solution. All the existing algorithms, though efficient, have some shortcomings. The current study proposes an alternate solution algorithm for the problem that is more efficient in terms of computational time than the existing algorithms. The results justifying the underlying theory of the proposed algorithm are given. Further, a detailed comparison of the computational behaviour of all the algorithms for randomly generated instances of this problem, of different sizes validates the efficiency of the proposed algorithm.

     

Extraction of the CKM matrix element V<Subscript>us</Subscript> from the hyperon semileptonic decays

The chiral constituent quark model with configuration mixing ( c \chi CQM _config , which is successful in explaining the weak vector and axial-vector form factors for the strangeness-changing as well as strangeness-nonchanging hyperon semileptonic decays at Q ² = 0 , has been extended to determine the CKM matrix element V _us for the strangeness-changing decays. The implications of the effect of the SU(3) symmetry breaking, Q²-dependence and radiative corrections on the form factors and V _us have also been investigated. It is found that the results with SU(3) symmetry breaking show considerable improvement over the SU(3) symmetric results when compared with the existing experimental data. The inclusion of the Q²-dependence and radiative corrections in form factors have only a small effect on the prediction of V _us as is expected from the theory.     

Existence of nonoscillatory solutions of higher order neutral differential equations with distributed deviating arguments

In this work, we consider the existence of nonoscillatory solutions of variable coefficient higher order linear neutral differential equations with distributed deviating arguments. We use the Banach contraction principle to obtain new sufficient conditions, which are weaker than those known, for the existence of nonoscillatory solutions.     

Generalized Bleustein-Gulyaev type waves in layered porous piezoceramic structure

The propagation of a Bleustein-Gulyaev (B-G) type wave in a structure consisting of multiple layers and a half-space of porous piezoelectric materials is theoretically studied. The solutions of the problem in terms of the mechanical displacements and electric potential functions are obtained for each layer and the half-space. The dispersion equation is obtained for electrically open and shorted boundary conditions by use of the transfer matrix method. A peculiar kind of B-G waves is investigated, which can propagate only in the layer over the half-space. The relationship between the piezoelectric constants and the dielectric constants is found for the existence of a peculiar kind of propagation modes. The numerical results in terms of the phase velocity and the electromechanical coupling factor with different thicknesses of the layer stack are presented.