Physics

The geometric nature of approximate Noether gauge symmetries
We find the geometrical set of equations corresponding to the approximate Noether gauge symmetry conditions of the perturbed geodesic Lagrangian for spacetimes. Using the obtained new set of approximate Noether symmetry equations which involves exact, first-order and second-order metrics, we calculate exact, first-order and second-order approximate Noether gauge symmetry vectors of the geodesic...


Evolution of the three-dimensional collagen structure in vascular walls during deformation: an in situ mechanical testing under multiphoton microscopy observation
The collagen fibers’ three-dimensional architecture has a strong influence on the mechanical behavior of biological tissues. To accurately model this behavior, it is necessary to get some knowledge about the structure of the collagen network. In the present paper, we focus on the in situ characterization of the collagenous structure, which is present in porcine jugular vein walls. An observat...
Bayesian quantum frequency estimation in presence of collective dephasing
We advocate a Bayesian approach to optimal quantum frequency estimation—an important issue for future quantum enhanced atomic clock operation. The approach provides a clear insight into the interplay between decoherence and the extent of prior knowledge in determining the optimal interrogation times and optimal estimation strategies. We propose a general framework capable of describing local ...


Topological origin of quasi-flat edge band in phosphorene
Phosphorene, a honeycomb structure of black phosphorus, was isolated recently. The band structure is highly anisotropic, where the k x direction is Dirac-like and the k y direction is Schrödinger-like. A prominent feature is the presence of a quasi-flat edge band entirely detached from the bulk band in phosphorene nanoribbons. We explore the mechanism of the emergence of the quasi-flat band by...
Concurrently optimized cooperative pulses in robust quantum control: application to broadband Ramsey-type pulse sequence elements
A general approach is introduced for the efficient simultaneous optimization of pulses that compensate each otherʼs imperfections within the same scan. This is applied to Ramsey-type experiments for a broad range of frequency offsets and scalings of the pulse amplitude, resulting in pulses with significantly shorter duration compared to individually optimized broadband pulses. The advantage of...


Tunable thermoelectricity in monolayers of MoS 2 and other group-VI dichalcogenides
We study the thermoelectric properties of monolayers of MoS 2 and other group-VI dichalcogenides under circularly polarized off-resonant light. Analytical expressions are derived for the Berry phase mediated magnetic moment, orbital magnetization, as well as thermal and Nernst conductivities. Tuning of the band gap by off-resonant light enhances the spin splitting in both the valence and conduc...
Self-organized metal-semiconductor epitaxial graphene layer on off-axis 4H-SiC(0001)
The remarkable properties of graphene have shown promise for new perspectives in future electronics, notably for nanometer scale devices. Here we grow graphene epitaxially on an off-axis 4H-SiC(0001) substrate and demonstrate the formation of periodic arrangement of monolayer graphene on planar (0001) terraces and Bernal bilayer graphene on ((11bar 20)) nanofacets of SiC. We investigate these l...

Solid-state tris(2,2’-bipyridyl)ruthenium(II) electrogenerated chemiluminescence sensor based on ionic liquid/sol-gel titania/Nafion composite film
The feasibility of being able to control the selectivity of solid-state tris(2,2’-bipyridyl)ruthenium(II) (Ru(bpy)3 2+) electrogenerated chemiluminescence (ECL) sensor is proposed by selecting ionic liquids with appropriate hydrophobicity in the sol-gel titania/Nafion composite film. Four different kinds of ionic liquids with different hydrophobicity such as 1-butyl-3-methylimidazolium hexafl...
The Electrochemical Reduction of Nitrate Ion on Polypyrrole Coated Copper Electrode
Reduction of nitrate ion was investigated on copper and polypyrrole coated copper electrode (PPy-Cu) in acidic aqueous medium. The nitrate concentration was increased, from 5 to 200 Mm (0.1 M LiClO4 + 0.001 M HClO4 + x mM KNO3; x=5, 20, 50, 100 and 200 mM). The applied potentials were -0.4, -0.6, -0.8, -1.0 and -1.2 V [Ag/AgCl]. Depending on these parameters, nitrate reduction gave the same pro...

A novel sandwich–type noncompetitive immunoassay of diethylstilbestrol using β-cyclodextrin modified electrode and polymer-enzyme labels
A novel sandwich-type noncompetitive electrochemical immunosensor was successfully developed for detecting diethylstilbestrol (DES). First, a novel label (EV/PtNPs-DES ab) was fabricated by immobilizing numerous platinum nanoparticles (PtNPs) and antibody of DES (DES ab) on the EnVisionTM polymerase chelate (EV). Because DES has two symmetrical phenol groups in the formula, β-cyclodextrin (β-...
New electrode architectures based on poly(methylene green) and functionalized carbon nanotubes: characterization and application to detection of acetaminophen and pyridoxine
New electrode platforms have been constructed containing the redox polymer poly(methylene green) (PMG) and functionalized carbon nanotubes (fCNT) in two configurations, the first containing MG electropolymerised on a graphite composite electrode (CE) and covered with fCNT (fCNT/PMG/CE), the second having the MG electropolymerised on top of fCNT modified CE (PMG/fCNT/CE). Modified electrodes wit...

Magnetic Field Tunability of Square Tapered No-Core Fibers Based on Magnetic Fluid
A magnetic-field-tuned photonics device based on magnetic fluid (MF) and a square tapered no-core fiber (NCF) sandwiched between two single-mode fibers (SMFs) has been demonstrated experimentally and theoretically. The enhanced evanescent field effect in the NCF is achieved by tapering the square NCF utilizing a fusion splicer. The spectral dependence of the proposed device on the applied magne...
Fiber Bragg Grating-Based System for 2-D Analysis of Vibrational Modes of a Steel Propeller Blade
This paper reports results obtained using fiber Bragg grating (FBG)-based sensors to investigate the displacement mode shapes of a cantilevered steel propeller blade, using FBG arrays for vibration monitoring for the first time. The experimental data obtained are cross compared with those from a finite element analysis of the same blade, undertaken using proprietary software. In the experimenta...
Resistive states in wide superconducting films induced by dc and ac currents (Review Article)
This review is devoted to the studies of the resistive state in wide superconducting films induced by dc and ac currents in the absence of an external magnetic field. It is found experimentally that the current-voltage characteristics and their parameters are well described by the Aslamazov–Lempitskii theory of the resistivevortex state, which has long been lacking an adequate evidence to sup...
Tunneling spectra of break junctions involving Nb3Sn
The electronic gap structure of Nb3Sn was measured by the break-junction (BJ) tunneling technique. The superconducting gap values are estimated to be in the range 2Δ = 4–5.5 meV at T = 4.2 K as follows from the observed distinct conductance peaks. In addition to the superconducting gap structure, we observed reproducible hump-like structures at the biases of about ±20 and ±50 mV. Such ...