Spectroscopic ellipsometry (SE) together with the optical transmission method is successfully used to determine refractive index n and absorption coefficient α of undoped gallium nitride film over spectral range 0.78–4.77 eV photon energy. The SE measurement carried out at angle incidence 60° 1.5–4.77 energy 0.78–3.55 range. obtained by both methods show unique results in overlap wavelength region. Refractive found follow Sellmeir dispersion relationship n2(λ)=2.272+304.72/(λ2−294.02) below...

Given a vector $x$ and closed convex cone $\mathcal{C}$ in an $n$-dimensional inner product space. If is not the dual of $\mathcal{C}$, then maximal angle between greater than $\frac{\pi}{2}$. In this case, formula regarding given terms metric projection $-x$ on $\mathcal{C}$. Critical angles two cones that are or equal to $\frac{\pi}{2}$ shown be Nash by using formula. Furthermore, some properties critical pairs sum $n\times n$ positive semidefinite all symmetric nonnegative matrices...

<title>Abstract</title> Aiming at the problem that traditional Twin Support Vector Machine (TSVM) is sensitive to noise and outliers, this paper proposes a twin support vector machine model based on generalized adaptive Huber loss function (GAHTSVM). Via dynamically adjusting robust parameters \(s\), can effectively suppress adverse effects of noisy data points decision function, improve sparsity by introducing insensitive region design. For non-convex optimization problems, concave-convex...

Nanocrystalline TiO2 thin films, deposited on single crystal Si (100) substrates under different temperature conditions by the sol–gel dip coating method, have been investigated for their optical properties using ultraviolet-visible spectroscopic ellipsometry. A gradual increase in refractive index, n, with increasing annealing up to 600 °C, and thereafter a sharp n at 800 °C of observed. For heat-treated low (400 °C) annealed is found be higher film–substrate interface than film surface...

Amorphous and nanocrystalline TiO(2) thin films coated on a vitreous silica substrate by solgel dip coating method are investigated for optical properties spectroscopic ellipsometry (SE) together with transmission spectroscopy. A of analysis SE data to determine the degree inhomogeneity has also been presented. Instead refractive index, volume fraction void assumed vary along thickness an excellent agreement between experimental calculated below fundamental band gap obtained. The spectrum...

A method of analysis spectroscopic ellipsometry (SE) measurement data is proposed for AlxGa1−xN/GaN heterostructures grown on sapphire substrates. The SE measured at three angles incidence, 40°, 50°, and 60°, are simultaneously fitted assuming the dielectric function to consist a Sellmeir dispersion equation free-exciton absorption term. refractive index n extinction coefficient k undoped AlxGa1−xN films determined in spectral range 1.5–4.13 eV photon energy. transition energy free exciton,...

Infrared reflectivity measurements have been carried out on samples with structures of GaN/sapphire and AlxGa1−xN/GaN/sapphire as well sapphire substrates. Analyses the reflectance data using Kramers–Kronig technique fitting spectra GaN AlxGa1−xN analytical expressions made. The high-frequency dielectric constant ε∞ transverse phonon frequency ωTO, are found to vary from 5.15 4.2 559.7 586.4 cm−1, respectively, when composition x is varied 0 0.35 at room temperature. E2 mode, which arises...

Abstract Owing to their extraordinary photophysical properties, organometal halide perovskites are emerging as a new material class for X‐ray detection. However, the existence of toxic lead makes commercialization questionable and should readily be replaced. Accordingly, several alternatives have been introduced into framework conventional perovskites, resulting in various perovskite dimensionalities. Among these, Pb‐free lower dimensional (LPVKs) not only show promising detecting properties...

Infrared polarized reflectance at three incidence angles (18°, 45°, and 75°) was measured from 300 to 1200 cm−1 for sapphire GaN/sapphire 295 K. The approximately 1.5 μm thick film of GaN grown directly on c-plane by metal-organic chemical vapor deposition. optical anisotropy the substrate studied fitting with a suitable model five- three-mode spectra, respectively, different incident all simultaneously. In procedure, we adopted technique, i.e., first numerical derivative spectra improve...

Bird Mating Optimizer (BMO) is a novel meta-heuristic optimization algorithm inspired by intelligent mating behavior of birds. However, it still insufficient in convergence speed and quality solution. To overcome these drawbacks, this paper proposes hybrid (TLBMO), which established combining the advantages Teaching-learning-based (TLBO) (BMO). The performance TLBMO evaluated on 23 benchmark functions, compared with seven state-of-the-art approaches, namely BMO, TLBO, Artificial Bee Bolony...

This note deals with the optimality conditions of set-valued unconstraint optimization problem in real normed linear spaces. Based upon concept contingent epiderivative, unified necessary and sufficient for global proper efficiency vector involving cone-arcwise connected mapping are presented.

abstract Path planning of unmanned aerial vehicle (UAV) is an optimal problem in the complex combat field environment. Teaching-Learning-Based Optimization (TLBO) algorithm presented under inspiration teaching-learning behavior a classroom. In this paper, applied to design path by search angle and distance, which better at higher convergence speed shorter route can be found. Finally experimental comparison results show that TLBO feasible effective method for UAV planning.

Bird Mating Optimizer (BMO) is a novel meta-heuristic optimization algorithm inspired by intelligent mating behavior of birds. However, it still insufficient in convergence speed and quality solution. To overcome these drawbacks, this paper proposes hybrid (TLBMO), which established combining the advantages Teaching-learning-based (TLBO) (BMO). The performance TLBMO evaluated on 23 benchmark functions, compared with seven state-of-the-art approaches, namely BMO, TLBO, Artificial Bee Bolony...

This paper deals withthe characteristics of global proper efficient points and theoptimality conditions vector optimization problems involvinggeneralized convex set-valued maps. Several equivalent properties ofglobal are proposed. Utilizing cone-directedcontingent derivative, it presents the unified necessary andsufficient optimality for elementin problem with cone-arcwise connectedset-valued mapping.

A twin bounded support vector machine (TBSVM) is a phenomenon of symmetry that improves the performance traditional classification algorithm. In this paper, we propose an improved model based on TBSVM, called Welsch loss with capped L2,p-norm distance metric robust (WCTBSVM). On one hand, by introducing in problem non-sparse output regularization term solved; thus, generalization and robustness TBSVM principle minimizing structural risk realized. other bounded, smooth, non-convex function...