Interactive effects of local smoothing window size and fundamental frequency on shimmer calculation

Slow amplitude modulation of human voice was approximated by a sinusoidal wave. The theoretical effects of smoothing window size, F₀, and modulation frequency on window amplitude average as well as calculated shimmer were mathematically derived. Subsequently, the theoretical predictions were tested using idealized and real voice signals from normal speakers. The theoretical and experimental results suggest that shimmer (when calculated using a smoothing window) is a function of window duration and modulation frequency. Window duration when defined as a constant number of pitch periods varies from speaker to speaker depending on their F₀. It may not be desirable to use local smoothing windows with a constant number of cycles for shimmer computation, especially if voices with known low-frequency amplitude modulations but notably different fundamental frequencies are compared.     

A minimal model for two-component FIMP dark matter:A basic search

In the multi-component configurations of dark matter phenomenology,we propose a minimal twocomponent configuration which is an extension of the Standard Model with only three new fields;one scalar and one fermion interact with the thermal soup through Higgs portal,mediated by the other scalar in such a way that the stabilities of dark matter candidates are made simultaneously by an explicit Z2 symmetry.Against the most common freeze-out framework,we look for dark matter particle signatures in the freeze-in scenario by evaluating the relic density and detection signals.A simple distinguishing feature of the model is the lack of dark matter conversion,so the dark matter components act individually and the model can be adapted entirely to both singlet scalar and singlet fermionic models,separately.We find dark matter self-interaction as the most promising approach to probe such feeble models.Although the scalar component satisfies this constraint,the fermionic one refuses it even in the resonant region.     

Observation on Symmetry Properties of Sodium Zinc(II)-2,9,16,23-phthalocyanine Tetracarboxylate in Water:NaOH Solution

The shift of the Q-band of sodium zinc(II)-2,9,16,23-phthalocyanine tetracarboxylate (ZnPc(COONa)₄) to about 800 nm is attributed to the influence of the electron-donating property of the carboxylate groups substituted in the β–position. ZnPc(COONa)₄ which was found to have a symmetry of D _2h characterized by a splitting of the Q transition. This splitting was interpreted by the formation of dianionic symmetric ZnPc(COONa)₄ resulting from the dissociation of the pyrrole protons as well as the possibility of Na⁺ dissolution of ZnPc(COONa)₄ in the aqueous solution of NaOH.     

An ultra-small heterostructure wavelength division multiplexer (WDM) with the ability to select two wavelengths from the s-band

In this article, a photonic crystal channel drop filter (CDF) based on \(2\times 3\) ring resonators is presented. At first, the effects of changing the radius of lattice rods and the lattice dielectric constant on the dropping efficiency of a 3-port CDF with one resonator are investigated. Then by developing this base structure, a new 4-port heterostructure CDF composed of two regions with rods made of silicone and germanium is presented, which can operate in the ‘S’ band of the communication window. The photonic crystal heterostructure CDF consists of a horizontal waveguide and two ring resonators that have been installed, in symmetry to the horizontal axis, in two regions with different refractive indices. These ring resonators act as energy couplers and capture at their resonant frequencies the electromagnetic energy which is propagated in the bus waveguide. For the analysis of transmission characteristics and the band structure of the filter, two methods have been employed: the two-dimensional Finite–difference time domain method and the Plane Wave Expansion method. In the final structure, dropping efficiencies of 97 and 89 % can be achieved at ports D and B, respectively, and also an acceptable quality factor can be obtained in the communication window. The overall size of this device is 174.14  \(\upmu \hbox {m}^{2}\) . Due to its small size, this structure can be used in Wavelength Division Multiplexer applications in the Optical Integrated Circuits.     

Improving anti-reflectivity and laser damage threshold of \hbox {SiO}_{2}/\hbox {ZrO}_{2} thin films by laser shock peening at 1064 nm

In this study, anti-reflection (AR) \(\hbox {SiO}_{2}/ \hbox {ZrO}_{2}\) thin films with 3-layers were designed and fabricated by the essential Macleod software and physical vapor deposition, respectively. In order to improve the optical and physical properties of the prepared samples, laser shock peening (LSP) technique was applied. For this purpose, an Argon Fluoride Excimer laser \((\lambda =193 \,\text {nm})\) with 110 and 240 mJ energies and 1 Hz frequency at different pulses was used. The effect of LSP method in improving transmissions and laser damage thresholds of the prepared samples was proved by using UV–Vis–IR spectroscopy in the wavelength range of 400–1200 nm and international standard ISO11254 at 1064 nm. In addition, scanning electron microscopy was used to check the effect of applying LSP.     

Voltammetric determination of hydroxylamine in water samples using a 1-benzyl-4-ferrocenyl-1H-[1,2,3]-triazole/carbon nanotube-modified glassy carbon electrode

A modified glassy carbon electrode has been constructed using a 1-benzyl-4-ferrocenyl-1H-[1,2,3]-triazole along with multiwalled carbon nanotubes. The electrochemical behaviour of modified electrode has been investigated by cyclic voltammetry. Electrocatalytic activity of the modified electrode was investigated for the oxidation of hydroxylamine in 0.1 M phosphate-buffered solution of pH 8. The modified electrode showed electrocatalytic response to the oxidation of hydroxylamine at the potential of 330 mV. The linear range and detection limit for the detection of hydroxylamine in the optimum condition were found to be 4.0?×?10^?7 to 6.75?×?10^?4 M and 28.0?±?1.0 nM, respectively. Finally, the method was employed for the determination of hydroxylamine in water samples.     

Generalized negative flows in hierarchies of integrable evolution equations

A one-parameter generalization of the hierarchy of negative flows is introduced for integrable hierarchies of evolution equations, which yields a wider (new) class of non-evolutionary integrable nonlinear wave equations. As main results, several integrability properties of these generalized negative flow equation are established, including their symmetry structure, conservation laws, and bi-Hamiltonian formulation. (The results also apply to the hierarchy of ordinary negative flows). The first generalized negative flow equation is worked out explicitly for each of the following integrable equations: Burgers, Korteweg-de Vries, modified Korteweg-de Vries, Sawada-Kotera, Kaup-Kupershmidt, Kupershmidt.     

Analytic study of sixth-order thin-film equation by tan(<Emphasis Type="BoldItalic">ϕ</Emphasis>/2)-expansion method

A improvement of the expansion methods, namely, the improved \(\tan (\phi (\xi )/2)\)-expansion method for solving the sixth-order thin-film equation is proposed. As a result, many new and more general exact traveling wave solutions are obtained including singular kink-type solutions. We obtained the further solutions comparing with other methods as Flitton and King (Eur J Appl Math 15:713–754, 2004) and Taha et al. (J King Saud Univ Sci 26:75–78, 2014). Recently this method is developed for searching exact traveling wave solutions of nonlinear partial differential equations. Abundant exact traveling wave solutions including kink and rational solutions have been found. These solutions might play important role in engineering and physics fields. Also the results demonstrate that the introduced method is powerful tools for solving the nonlinear partial differential equations.