Electronic and vibrational spectra of CrO2−4 in cesium halide lattices

The electronic spectra of CrO^2?₄ ions embedded in cesium halide lattices show two well defined bands due to dipole allowed transitions along with some weak bands due to forbidden transitions. All the above bands are interpreted in terms of transitions within molecu ar orbital levels using the Ballhausen and Liehr scheme. It is observed that superposed on the electronic transitions there is a vibrational fine structure which arises due to the coupling between the electronic transitions and the totally symmetric stretching frequency of the ion. IR absorption spectrum of Analar grade CsI :CrO^2?₄ shows seven lines, whereas Specpure CsI :CrO^2?₄ shows five lines. The above spectra are interpreted on the basis of different local symmetries of CrO^2?₄ ions in the lattice.     

Doppler shift with Archimedes Optimization Algorithm for localizing unknown nodes in underwater sensor networks

The issue of underwater sensor network (UWSN) localization has led to the aim of techniques presented in recent years. In this paper, we develop Doppler shift with Archimedes Optimization Algorithm for localizing unknown nodes in UWSN. The projected method predicts that sink node plays a major function in managing the computational load contrasted with the remaining nodes in the network of underwater. This node localization is proceeding with frequency shifts of sound waves contrasted toward real, which are present once observer in addition source can be mobile as they do in a marine atmosphere. The proposed technique is utilized to compute the estimated position of an unknown sensor node; here Archimedes' optimization algorithm is utilized to reduce the error during localization of nodes in UWSNs. This proposed technique can be enhancing the accuracy of the localization of nodes in UWSNs. This proposed methodology can be implemented and evaluated with the help of performance metrics. To validate the proposed technique's efficiency, it is contrasted with conventional techniques like Particle Swarm Optimization (PSO) and Whale Optimization Algorithm (WOA).     

Improved SCF interaction energy decomposition scheme corrected for basis set superposition effect

A modified scheme for SCF interaction energy decomposition has been proposed where the nonphysical basis set superposition error (BSSE ) has been corrected by means of the counterpoise method. A new procedure to separate the exchange and induction energy terms free of nonphysical BSSE has been tested in the case of the H₂O dimer. The first order BSSE appears to be non-negligible for strong hydrogen bonded complexes. In addition the scheme allows separation of the long-controversial charge-transfer contribution within the induction term, which has been considerably overestimated in previous studies.     

Context-dependent photodimerization in isolated thymine-thymine steps in DNA

The effect of 280 nm irradiation on a family of synthetic DNA hairpins possessing an alkane linker connecting a six-base pair stem having a single T-T step located at different positions within the hairpin has been investigated. A single adduct assigned to the product of 2+2 dimerization is obtained except in the case of a T-T step located adjacent to the linker, in which case both 2+2 and 6-4 adducts are obtained. The efficiency of dimerization is similar for three hairpins having a T-T step located within the duplex interior. Lower efficiency is observed for a T-T step located at the open end of the hairpin and in T overhangs, whereas higher efficiency is observed for the T-T step adjacent to the linker and in a single T bulge. The context-dependence of dimerization efficiency is discussed.     

Real-time separation of perfusion and oxygenation signals for an implantable sensor using adaptive filtering

In this paper, an adaptive filtering algorithm to separate signals due to perfusion and oxygenation has been developed using an 810-nm source, in addition to 660-nm and 940-nm sources, as an internal reference due to its limited oxygen sensitivity. The newly developed algorithm was tested using Monte Carlo simulated data to prove the effectiveness of the 810-nm reference and adaptive algorithm. Following the simulation, an in vitro model was developed to test the algorithm that used a blood flow through system wrapped with tissue. The system had the ability to isolate the effects of perfusion and oxygenation and the algorithm accurately captured the changes in these signals with reliable consistency. Using the serosal surface of the swine jejunum, in vivo data was also taken to analyze the algorithms response to fluctuating perfusion levels like that seen in hemorrhaging or failing transplants. The algorithm was able to extract the perfusion information from the oxygenation information in this in vivo study. Overall, it was shown that an adaptive filtering algorithm using an 810-nm reference has provided a means to separate oxygenation and perfusion.     

Positron annihilation measurements across the superconducting transition in Y1Ba2Cu3O7−x

Positron lifetime and Doppler broadened annihilation radiation lineshape measurements have been carried out in Y₁Ba₂Cu₃O_7−x as a function of temperature in the range of 300 K to 58 K. The positron lifetime and the peak parameter of the annihilation radiation lineshape are observed to decrease on lowering the temperature without showing any discontinuous change across the superconducting transition temperature of 90 K as determined by susceptibility measurements. The variation of positron annihilation parameters with temperature in the superconducting state is significantly larger than that in the normal state. This is qualitatively explained in terms of the dimerization of oxygen ions in the superconducting state of Y₁Ba₂Cu₃O_7−x .     

Some studies on wave refraction in relation to beach erosion along the kerala coast

Using the British Admiralty bathymetric charts off the West Coast of India and employing the graphical method of constructing wave refraction diagrams, an attempt is made to study the behaviour of the shortperiod waves (4, 5 and 6 seconds) which are found to affect the coast generally in the neighbourhood of Cochin Port entrance. Nineteen stations, at intervals of roughly one mile, are chosen around the three-fathom line in this area. Considering a probable field of approach of deep-water waves, limited to a cone of 90°, five directions of approach are chosen at intervals of 22 1/2;° in the range of 202 1/2° to 292 1/2°. Refraction diagrams are prepared for these directions and periods, and from these, the refraction functions and directional parameters are evaluated for each station. The possible directions of flow of long-shore current and the areas vulnerable to erosion and sedimentation are investigated.     

Frequency doubling of femtosecond erbium-fiber soliton lasers in periodically poled lithium niobate

We report efficient frequency doubling of passively mode-locked femtosecond erbium-fiber lasers. Quasi-phase-matched second-harmonic generation in periodically poled lithium niobate is used to generate 8.1 mW of 190-fs (FWHM), 90-pJ pulses at 777 nm with a conversion efficiency greater than can be obtained with existing birefringently phase-matched nonlinear materials. A dispersion-compensation-free soliton oscillator generating transform-limited 230-fs (FWHM) pulses at 1554 nm is used as a pump laser.