查看更多>>摘要：A Mach-Zehnder interferometer sensor is designed, which includes a cascade structure of single-mode fiber (SMF)-no-core fiber (NCF)-few-mode fiber (FMF)-no-core fiber (NCF)- single-mode fiber (SMF) (SNFNS). In this structure, the NCF is used as the input and output coupler, and the FMF is used as the sensing region. In the measurement range, the SNFNS sensor has three interference dips. Among them, temperature and humidity can be measured simultaneously through the dip2 and the dip3, temperature and refractive index can be measured simultaneously by the dip1 and dip2. The temperature sensitivities are 0.063 nm/degrees C, 0.013 nm/degrees C and 0.095 nm/degrees C in the range of 30 degrees C similar to 85 degrees C. When refractive index changes from 1.333 to 1.365, the refractive index sensitivities of the dip1 and the dip2 are 134.17 nm/RIU and 53.76 nm/RIU, respectively, the changes of the dip3 are not noticeable. When humidity changes from 30%RH to 70%RH, the humidity sensitivities of the dip2 and dip3 are 0.034 nm/%RH and 0.025 nm/%RH, respectively, the changes of the dip1 are not noticeable. Furthermore, the structure has the merits of simple construction, good repeatability, and good stability.
Portillo, M. ChavezMoreno, O. PortilloMora-Ramirez, M. A.Avendano, C. Bueno...
12页
查看更多>>摘要：In a previous report, some morphological, structural, and optical properties of NdOHCO3 to Nd2O3 transition were presented. This paper continues investigating this interesting inorganic nanomaterial, proposing the creation of the coordination complex [Nd(NH3)(6)](3+) ion during crystalline growth as a crucial step for the growth of NdOHCO3 nanocrystals. A concise experimental-theoretical model is detailed in order to understand the spherical-like crystalline growth observed. The orthorhombic and cubic phases for NdOHCO3 and Nd2O3 nanocrystal samples were identified from the X-Ray diffraction results. In addition, the average grain size was estimated for each sample: NdOHCO3 similar to 15.31-18.82 nm and Nd2O3 similar to 45.10-59.01 nm. Other optical parameters like absorbance, transmittance, and reflectance are examined. The Urbach energy (E-u) model allows us to investigate the degree of absorption. The Maxwell-Boltzmann statistical (MBS) model results fit well with the experimental photoluminescence (PL) spectroscopy data registered, implying that native intrinsic crystalline defects behave as free particles and the emission bands overlap 4f(4)s(2) -> 4f(4)s(2) electronic intra-transitions. The PL spectra show two emission bands: Yellow similar to 3.10-1.55 eV and Red > 1.99 eV. Finally, the trap densities of NdOHCO3 (similar to 1.08 x 10(14) cm(-3)) and Nd2O3 (similar to 9.64 x 10(13) cm(-3)) were estimated.
查看更多>>摘要：The convenience of the network has brought the copyright crisis of some multimedia works. Therefore, a secure digital watermarking algorithm is urgently needed to realize the copyright maintenance of digital works. A blind digital watermarking algorithm using approximate Hadamard transform is presented in this paper. Since Hadamard transform has a certain energy aggregation effect, in this paper, the principle of energy concentration of Hadamard transform is explored, and the Hadamard transform is slightly treated, so that the multiple increase of large energy coefficient is realized. This modified approximate Hadamard transform is applied to the process of changing from spatial domain to transform domain in the embedding and extraction stage of our proposed watermarking algorithm. In this algorithm, the color image digital watermark is hided in the maximum energy coefficient of color host image in transform domain by using the idea of quantization. In the extraction stage, the watermark image can be extracted completely without the participation of any original information. In order to check on the feasibility of the algorithm, a large number of simulation experiments have been done. The results of simulation experiments show that the proposed algorithm has excellent effect in various performance index.
查看更多>>摘要：In this work, we analyze geometric aberrations in the visualization of microparticles (MP) in optical trapping. To this aim, we perform two modifications of the Gerchberg-Saxton(GS) method. The first one, to obtain the irradiance distribution of the MP in video captures of optical trapping applying a Gaussian mask obtained by a proper gray tone value after analyzing the corresponding histogram. The second one, to include a 2D Legendre polynomial fit to the iterative GS process to recover the phase and 3D profile of the MP from the recovered irradiance. We carry out this procedure to retrieve the irradiance and phase of 4 different chambers' configurations in optical trapping with colloidal mixtures of different MP sizes. Finally, we analyze in the recovered 3D profile the geometric aberrations introduced by different experimental setups. We compare and analyze our results, including the Zernike aberrations coefficients.
查看更多>>摘要：The proposed work focuses on the detection of lung cancer using a microstrip patch antenna. A compact microstrip patch antenna operating at ISM band has been designed and placed on healthy as well as cancer affected lung (different stages) phantom. Scatter and other parameters are observed, and data set is created for healthy as well as for each stage of cancerous lung. Variation because of cancer and its stages in the antenna parameters such as electric field, magnetic field, surface current, power flow, current density, power loss density, electrical energy density, and magnetic energy density, return loss, antenna gain, and tumor radius is observed. The created dataset has been further classified to differentiate a healthy lung from a cancerous one and its stages using Random Forest machine learning algorithm with an accuracy of 93.75%.
查看更多>>摘要：In this work, The MAPbI(3(1-x))B(3x) thin films with different percentage (x% = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1) was successfully deposited on zinc oxide (ZnO) by spin coating technique. Herein we report the study of monovalent halide anion bromide (Br-) doped methylammonium lead iodine (MAPbI(3)). Br doping shown to be efficient to improve the optoelectronic properties and stability of MAPbI(3(1-x))B-3x/ZnO heterojunction. We investigate the effect of x% of bromine on the composition and morphology of films by X-ray diffraction (XRD), spectroscopy electron microscopy(SEM),Photoluminescence (PL) and UV-visible spectroscopy. The MAPbI(3(1-x))B(3x)/ZnO films show that an adequate amount of x% Br leads to a homogeneous perovskite film with large grains, no pinholes with the band gap between 1.55 and 2.1 eV and the photoluminescent emission spectrum starts with the value 538 nm (MAPbBr(3)) up to780 nm (MAPbI(3)).
Alfano, RobertMazhar, Shah Faisal B.Sharonov, MikhailShi, Lingyan...
9页
查看更多>>摘要：Extreme spectral broadening has been theoretically simulated from the index of refraction changes from the envelope response to the fifth- and third-order susceptibilities from self-phase modulation (SPM) under the influence of an extremely high-intensity femtosecond laser pulse to potentially produce spectral broadening changes extending from extreme X-rays, UV, visible, THz down to DC. The theoretical results show that an extremely high-intensity pulse as high as on the order of 10(14)similar to 10(16) W/m(2) can influence the fourth-order refractive index arising from fifth-order susceptibility large enough that the nonlinear n(4)I(0)(2) term to overtakes the n(2)I(0)(2) term from the third-order susceptibility to produce the ultra-supercontinuum broadening in the liquids such as CS2 and rare gas liquids and solids such as calcite, ZnO, Si, Argon, and Krypton. There has been experimental verification at lower intensities that the SC is symmetrical in frequency about laser frequency for say a Gaussian pulse extends from, UV visible, NIR, to MIR by many researchers using various states of matter. This paper provides an opportunity to extend the SPM model from X-rays to DC to form Ultra Supercontinuum Generation (USCG) using extreme intensity fs pulses in the four states of matter: gases, liquids, solids, and plasmas. At the highest intensity, a continuum with weaker intensity goes towards the X-ray region on the anti-Stokes side.
查看更多>>摘要：To solve the problem that existing binocular stereo matching algorithms have low matching accuracy in discontinuous disparity and low texture area, a stereo matching algorithm based on Census transform and texture filtering is proposed. The weighted Census transform circular template is used to carry out the matching cost, which reflects the influence of the distance between neighborhood pixels and target pixels on the calculation and expands the perception range of target pixels; the texture filtering method is used for cost aggregation, which highlights the image structure information and smooths the internal texture. The experimental results show that the stereo matching algorithm proposed in this paper can effectively reduce the mismatching rate of images, the disparity map obtained has less noise, and the matching effect is better when the pattern texture is relatively dense.
Khudiar, Shahad S.Nayef, Uday M.Mutlak, Falah A-HAbdulridha, Sarah K....
8页
查看更多>>摘要：ZnO nanostructures have lately been deemed an effective material for fabricating gas sensors, As a result, ZnO nanoparticles are commonly utilized to make effective gas sensors for detecting a variety of hazardous and poisonous chemicals. The current review article focuses on nitrogen dioxide (NO2) gas sensor advances based on ZnO nanoparticles, X-ray diffraction confirmed the wurtzite structure, Surface roughness, layer homogeneity, and morphological structural analysis are studied using Atomic Force Microscopy (AFM). UV-vis and photoluminescence spectra were used to study the optical characteristics of the as-prepared ZnO nanostructures, The electrical properties such as the current density-voltage (J-V) measurements, Finally, the effects of adjusting operating temperature of NO2 gas sensor made from the prepared samples on sensor's sensitivity, recovery time and response time have been explored.
查看更多>>摘要：The image quality of distorted and faded art works may be improved by increasing the contrast, decreasing the noise, or sharpening the edges of the image. Such operations can be performed in various ways, such as filtering the image, histogram equalization techniques, decorrelation stretch, fuzzy techniques, etc. In this paper the fuzzy logic technique has been used to restore the distorted tribal artworks. The results obtained by this process have been compared with different histogram equalization (HE) techniques. The results of fuzzy logic and HE techniques that are mentioned in this paper are obtained using MATLAB. Parameters like Absolute Mean Brightness Error (AMBE), Peak to Signal Noise Ratio (PSNR), and Normalised Mean Square Error (NMSE) are tabulated and compared for the mentioned techniques.
NSTL
Elsevier