查看更多>>摘要：This work is devoted to the development of the octonion linear canonical transform (OLCT) theory proposed by Gao and Li in 2021 that has been designated as an emerging tool in the scenario of signal processing. The purpose of this work is to introduce octonion linear canonical transform of real-valued functions. Further more keeping in mind the varying frequencies, we used the proposed transform to generate a new transform called short-time octonion linear canonical transform (STOLCT). The results of this article focus on the properties like linearity, reconstruction formula and relation with 3D-short-time linear canonical transform (3D-STLCT). The crux of this paper lie in establishing well known uncertainty inequalities and convolution theorem for the proposed transform.
查看更多>>摘要：This article proposes the generation of both LHCP and RHCP waves simultaneously -at two distinct frequencies by using a single-layered compact polarization converter (PC). The proposed PC has been designed with a gold pattern inscribed on a polyimide substrate. A modified I-shaped structure with semi-circular curved ends provides a quadrature phase shift between the orthog-onal components of the incident electric field with a high transmission coefficient and low insertion loss across the two THz frequency bands. Two equivalent circuit models have been proposed for TE and TM modes separately. As a proof of concept of the proper functioning of the proposed PC, one dual-band linearly polarized antenna is designed and integrated with the PC. The linearly polarized radiated waves from the dual-band antenna across 1.55 THz and 4.05 THz have been successfully converted into both the RHCP and LHCP waves simultaneously. The integration of a simple profile PC with a dual-band THz antenna to produce dual CP radiated waves simultaneously are the key achievements of this proposed work. Moreover, the results of equivalent circuit models for both TE and TM modes are justified after proper validation with the full-wave EM simulation results. The proposed dual-band PC, dual-band THz antenna, and the integrated structures are systematically investigated using FEM-based CST Microwave studio.
查看更多>>摘要：This study reports the preparation and characterization of three new glasses: 75TeO(2) - 5Na(2)O(2) (20-x)BaO -xWO(3); labeled as TNB-W00, TNB-W0(3), and TNB-W10 for x = 0; 3; 10 mol%, respectively. The glasses were prepared using the solid state melt quench procedure. The optical parameters and radiation shielding parameters were estimated by measurement, FLUKA simulations and analytical calculations as required. Prepared glasses were yellowish but transparent in appearance. The density varied from 5.34 to 5.63 gcm(-3) for TNB-0 W - TNB-10 W. The band gap decreased from 3.12 to 2.97 eV as WO3 concentration grows. The refractive index increased from 2.36 to 2.40. The minimum (maximum) value of mass attenuation coefficient corresponded to 0.0334 (43.1380) cm(2)/g for TNB-0 W, 0.0336 (45.9624) cm(2)/g for TNB-3 W, and 0.034 (57.831) cm(2)/g for TNB-10 W. Analysis of other parameters showed that WO3 improved the gamma ray shielding ability of the glasses. The stopping power (Sp) of the charged particles (electron, proton, alpha-particles, and carbon ions) in the glasses with kinetic energy within the spectrum: 0.015-15 MeV calculated using the ESTAR, PSTAR, ASTAR, and the SRIM Monte Carlo code also showed improvement WO3 content. The fast neutron removal cross section equals 0.099 cm(-1 )for TNB-0 W, while for TNB-3 W and TNB-10, the value is 0.1024 and 0.1047 cm(-1) respectively Similarly, the (coherent and incoherent) scattering, absorption, and total cross section of thermal neutrons increased as the WO3 content of the glasses. Compared to some conventional shields, the present glasses present viable, transparent, and lead free alternatives for advanced shielding applications.
Yahia, I. S.Zahran, H. Y.Gomaa, Hosam M.Abul-Magd, Ashraf A....
11页
查看更多>>摘要：This work has been set up to estimate how the structural, and optical properties of the copper sodium borate-based glass change when the low bandgap oxide Cu2O3 is replaced by the one of the highest bandgap of Fe2O3. Where the value of the optical band gap of Cu2O3 (1.25-1.33 eV) is one half that of Fe2O3 (2.2 eV), approximately. Using the traditional fast quenching method, three categories of solid samples have been obtained, copper-free (one sample), iron-free (one sample), and copper-iron-doped (three samples). X-ray diffraction (XRD), Transmission electron microscopes (TEM), Fourier transform infrared (FTIR), and ultraviolet-visible (UV-Vis.) spectra have been used for structural and optical characterization. XED exhibited an amorphous nature for all the prepared samples, while the FTIR showed an increase in the number of the nonbridging oxygen atoms as a result of conversion from BO4 into BO3. Also, FTIR showed that Fe- cations occupied the interstitial spaces as FeO6. The Photoluminescence PL emission showed two emission peaks due to Fe2+, 3+ and Cu2+, 3+ multi-valence cations. The metallization factor, bulk density, and the optical band gaps increased when Cu2O3 was replaced by Fe2O3, with an increase in the values of the molar volume and the linear refractive index. Shielding parameter Zeff referred that the Fe-Free sample is more suitable for shielding applications than the Cu-Free sample, at low energies.
查看更多>>摘要：Laser cladding has become one of the most efficient surface technologies for Fe3Al coating preparation. Line energy density (defined as eta = P/v) reflects the comprehensive effect of the power and scanning speed of the laser beam on the quality of the obtained Fe3Al coatings. Herein, we found that line energy density of the laser beam has significant effect on the microstructure, phase and wear resistance properties of the obtained Fe3Al laser cladding coatings. Dry sliding wear tests were performed to understand the friction behavior and wear mechanism of the Fe3Al laser cladding coatings. The study revealed that the Fe3Al laser cladding coating obtained with a line energy density of 0.3 J/mm exhibits the optimized film quality and the best wear resistance properties, of which the average friction coefficient is 0.45, and the specific wear rate is 0.09 x 10(-3) mm(3).N-1.m(- 1).
查看更多>>摘要：Blind image deblurring aims to recover the latent sharp image from a given blurred image when the blur kernel is unknown. To solve this ill-posed problem, many researchers have studied various priors to guide the deblurring process. However, whether the image is sharp or not is mostly based on the subjective judgment of human eyes, and there is no unified objective standard. Since the response of blur to visual sensitivity can be modeled by a filtering method, we use human visual system (HVS) convolution filter to filter the target image to simulate the corresponding visual sensitivity. At the same time, we find that the local maximum variation values of the filtered image will be reduced after blurring process. Therefore, we propose a local maximum variation prior (LMV) based on visual sensitivity filtering and construct a new energy function according to LMV. Our method performs well in various scenarios. Compared with the most advanced algorithms, our model achieves good results on both benchmark datasets and natural images.
Gevorgyan, A. H.Golik, S. S.Vanyushkin, N. A.Efimov, I. M....
8页
查看更多>>摘要：In this paper we investigated the magneto-optical properties of helically structured photonic crystals taking into account the wavelength dependence of magneto-optical activity parameter and wavelength independence of Verdet constant. We compare the obtained results with the case of the wavelength independence of magneto-optical activity parameter. We investigated the peculiarities of spectra of rotation, ellipticity, reflection, photonic density of states, transmission nonreciprocity in these two cases. We showed that in general these results can essentially differ from one to another and wavelength dependence of magneto-optical parameter cannot be neglected.
查看更多>>摘要：Glass composition comprising of SiO2-Na2O-K2O-P2O5 with CaO/BaO were synthesised and characterized using XRD and UV-Vis spectroscopy. The optical features were analysed in terms of band gap (E-g), refractive index (n), molar refraction (R-M), molar polarizability (alpha(m)), reflection loss (R-LOSS), optical transmission (T-Optical), metallization criterion (M-criterion), dielectric constant (epsilon(Static), epsilon(Optical)), optical electronegativity (chi) and optical basicity (Lambda). The E-g of glasses acquired using Tauc's plot and ASF methods authenticates the applicability of both methods as equally good. The E-g value decreases, whereas n increases with an increase in alkaline earth metal oxides (CaO/BaO) content in the glass samples. The M-criterion exhibits metallic nature of the glasses. The R-M and alpha(m) decreases as CaO/BaO content increases; whereas R-LOSS and T-Optical remains constant for the glasses. The dielectric constants increase as CaO/BaO content increases. The photon attenuation parameters were investigated using MC simulations (PHITS and GEANT4) and theoretically using WinXCom. Among all glasses, S8 glass sample has highest mu/rho, mu, Z(eff), N-eff and lowest mfp values. Further, S8 glass has low values of both stopping power (S-P) and range (R-p); as required for shielding from charged particles. The slow and fast neutron shielding ability also escalates with an increase in CaO/BaO content in glass matrix. Comparative analysis confirms that S8 glass sample possess superior radiation shielding competency not only for neutral radiations (photon and neutron beams), but also for charged particles (e, p, alpha and C-ion beams) as compared to several commercial shielding materials.
Zayed, Elsayed M. E.El-Horbaty, MahmoudAlngar, Mohamed E. M.El-Shater, Mona...
7页
查看更多>>摘要：Object: We discuss for the first time, the perturbed resonant nonlinear Schrodinger equation (NLSE) with Kerr law nonlinearity and Bohm potential having a multiplicative white noise. Methods: Three integration schemes via modified simple equation method, sine-cosine method and Jacobi elliptic equation method are used. Results: We retrieve soliton solutions to the model, which are described using parametric constraints. Jacobi elliptic function solutions, bright, dark, singular soliton solutions are presented.
查看更多>>摘要：This paper proposes a novel color image encryption scheme of Liu Lorenz-XOR Zigzag Arnold (LLXZA) encryption algorithm. Firstly, to prove that the three-dimensional(3D) Liu system and the four-dimensional(4D) Lorenz system are in a hyperchaotic state, we performed the visual analysis of their key parameters, such as the Lyapunov exponent, bifurcation diagram, attractor, Poincare cross-section diagram and initial value sensitivity. Then, we adopt the 3D Liu hyperchaotic system as the primary hyperchaotic mapping scheme of the color image. The 4D Lorenz hyperchaotic system is discretized by the Runge-Kutta method to generate a pseudorandom number sequence of the control parameter with stronger randomicity. Furthermore, XOR, 3D Zigzag transformation, and 3D Arnold transformation are reset to construct the encryption scheme. Finally, we explored the security performance of the proposed scheme with the RGB grayscale histogram, pixel correlation, information entropy by color image simulation. The results verified that the LLXZA encryption algorithm can significantly improve the color image security performance and has superiorities in stable encryption effect, visual security, and robustness.
NSTL
Elsevier