Computation of the Epsilon-Subdifferential of Convex Piecewise Linear-Quadratic Functions in Optimal Worst-Case Time

Set-Valued and Variational Analysis - The epsilon-subdifferential of convex univariate piecewise linear-quadratic (PLQ) functions can be computed in linear worst-case time complexity as the...     

Study of electronic and optical properties of pure and metal decorated boron nitride nanoribbons (B15N14H14-X): first principle calculations

Density functional theory (DFT)/time dependent density functional theory (TDDFT) based calculations were performed for basis sets 6-31G for DFT and 6-31G (d), 6-31G (d,p) and 6-31+G (d,p) for TDDFT calculations on pure boron nitride nanoribbon (BNNR) B₁₅N₁₅H₁₄ and metal decorated B₁₅N₁₄H₁₄-X BNNRs, where X = Ni⁺, Fe⁺, Co, Cr⁺, Cu and Al. The metal doping ratio = 3.45% and the doping site (nitrogen atom), were fixed for all the BNNRs. Electronic properties dipole moment, binding energy and bandgap were determined. Absorption properties in the wavelength range (100–600 nm) were studied, and optical gaps, absorption wavelengths, oscillator strengths and dominant transitions were calculated. The effect of metal doping on the electronic and optical properties was investigated. Single metal doping shifts the electronic gap of pure BNNR from insulating to semiconducting nature. Red shift in the absorption wavelengths from ultraviolet to visible in all the BNNRs was noticed.     

Efficiency of the Incomplete Enumeration Algorithm for Monte-Carlo Simulation of Linear and Branched Polymers

We study the efficiency of the incomplete enumeration algorithm for linear and branched polymers. There is a qualitative difference in the efficiency in these two cases. The average time to generate an independent sample of configuration of polymer with n monomers varies as n ² for linear polymers for large n, but as exp(cn ^α) for branched (undirected and directed) polymers, where 0<α<1. On the binary tree, our numerical studies for n of order 10⁴ gives α = 0.333±0.005. We argue that α =1/3 exactly in this case. An erratum to this article can be found at .     

The partition problem

In this paper we describe several forms of thek-partition problem and give integer programming formulations of each case. The dimension of the associated polytopes and some basic facets are identified. We also give several valid and facet defining inequalities for each of the polytopes.Partial Support from NSF Grants DMS 8606188 and ECS 8800281 is gratefully acknowledged.     

Synthesis and structural characterisation of new Re(III) complexes using aldimines of α-amino acids as coligands

Complexes of the general formula [Re^III(L)Cl(PPh₃)₂] have been synthesised by reacting H₂L and [ReOCl₃(PPh₃)₂] in ethanol. Here H₂L represents imines of α-amino acids (glycine, l-alanine, l-valine, l-phenylalanine) derived from salicylaldehyde and naphthaldehyde. The crystal structure of one complex has been determined. The complexes are mononuclear, paramagnetic and display paramagnetic ¹H NMR in CDCl₃ solution. Their spectral and redox properties are scrutinised.     

Design of a Hybrid Fiber-Optic Network Using 3-D Optical Code Sequences

We present the design of a 3-dimensional (3-D) noncoherent optical hybrid network. We also report the design of a new family of 3-D codes for fiber optic hybrid networks. We show that the hybrid network allows for shorter bit times and a higher number of users, given a set chip rate, compared to previously conceived networks. These newly designed hybrid single-pulse-per-row (HSPR) codes have very low autocorrelation side-lobes and very small cross-correlation peaks. We compare the performance of our hybrid model using our codes with the Optical Orthogonal Codes (OOCs) and Temporal/Spatial (T/S) codes and show that the new network can support a greater number of users and higher data rates than those using OOCs and T/S codes.     

Spin squeezing and quantum correlations

We discuss the notion of spin squeezing considering two mutually exclusive classes of spin-s states, namely, oriented and non-oriented states. Our analysis shows that the oriented states are not squeezed while non-oriented states exhibit squeezing. We also present a new scheme for construction of spin-s states using 2s spinors oriented along different axes. Taking the case of s=1, we show that the ‘non-oriented’ nature and hence squeezing arise from the intrinsic quantum correlations that exist among the spinors in the coupled state.     

Uhf to Ka band upconverter

A balanced upconverter circuit has been developed in planar transmission line configuration using NEC GaAs beam lead Schottky barrier diodes. RF power output of +1.6 dBm SSB is obtained at Ka-band when up converter is driven by +17 dBm IF and +20 dBm LO signal.     

Sorption of some isomeric monohydric alcohols on egg albumin

Summary Sorption of iso-propyl, iso-butyl, sec-butyl, tert-butyl and iso-amyl alcohols on egg albumin has been studied at 35 °C by using quartz fiber spring technique. Sorption is related inversely to the molar volume of the sorbate. The specific surface area of egg albumin has been calculated by the BET method. The thermodynamic functions have also been evaluated.With 3 figures and 2 tables     

On the topological characterization of two-dimensional phase transitions

It is shown that for the two-dimensional planar-rotator model the variance of the number of vortices inside a large loop is proportional to the perimeter of the loop at all temperatures. A similar result holds for the variance of the charge inside a loop in the lattice Coulomb gas model. Hence a topological distinction between the high and low temperature phases of these models (area law versus perimeter law) is not possible.