查看更多>>摘要：In an inverse free-electron laser (IFEL) scheme, a comparative study of single electron acceleration is carried out using a tightly focused Gaussian laser beam along with helical and planar wiggler fields. The effect of laser and wiggler field parameters is analyzed on single-electron dynamics and its acceleration. For the laser field descriptions, up to fifth-order corrections are included in the diffraction angle to study the effect of a tight laser pulse on electron acceleration. The Lorentz equation is solved using the fourth-order Runge Kutta method. Our numerical results indicate that considerable electron energy is attained for the helical and planar wiggler both for the optimal laser and wiggler field parameters, respectively. The effect of the laser field, its waist -size, and the effect of the wiggler field and its tapering along undulator length is studied for both helical and planar wiggler. The total electron energy gain for the helical wiggler case is 1.3 GeV due to the long interaction length while for the planar wiggler case, the electron energy gain is limited to 300 MeV only due to its shorter interaction length. This comparative analysis will certainly help us to understand the electron dynamics in IFEL and show the importance of helical wiggler over planar wiggler.
Lahewil, Abdulwahab Salem ZarougZyoud, Samer H.Ahmed, Naser M.Omar, Ahmad Fairuz...
11页
查看更多>>摘要：In this study, zinc oxide (ZnO) thin films were utilized to create metal-semiconductor-metal (MSM) structured ultraviolet (UV) photodetectors using laser assisted chemical bath deposition (LACBD). For the first time, LACBD has successfully manufactured zinc oxide (ZnO) nanoclusters (NCs) with high-quality structural, optical, and electrical properties on a glass substrate coated with iron (Fe) to construct an MSM UV photodetector with high responsivity. The thin film was created by irradiating the chemical bath in situ using a continuous wave semiconductor laser with wavelength(460 nm), output power (1 W), and irradiation laser time (30 min). The thin film was characterized using field emission scanning electron microscopy (FE-SEM), energy dispersive Xray (EDX) analyses, and X-ray diffractometry (XRD). Our findings revealed that LACBD promoted the development of a high-crystallinity ZnO thin film. The effectiveness of ZnO NCs in UV detection has also been examined to account for the potential of these nanostructures. The device's current-voltage (I-V) characteristics were tested in dark and light situations, confirming the UV photodetector's excellent responsiveness and stability. Optical confinement, a high surface-tovolume ratio, and the superior structural quality of the NCs, as confirmed by time-resolved spectroscopy, are all factors in the great photodetector performance.
查看更多>>摘要：This paper presents a thresholding algorithm using an alternate forward-reverse flow-based partial differential equation (PDE)-based formulation. Additionally, revised models are augmented with fuzzy intensification and fuzzy rule-based structure tensor edge terms for handling degraded document images. Furthermore, an effective technique for enhancement of document images with extreme bleed-through is proposed to further improve binarization results. Comparisons with state-of-the-art PDE thresholding/binarization approaches show superior re-sults of proposed methods based on visual and objective analysis.
查看更多>>摘要：In this manuscript, we define antiferromagnetic microscale with electroosmotic velocity on spherical Heisenberg group. We construct optical electromagnetic spherical empty set (alpha) , empty set (t) , empty set (s) -flux by using electromagnetic flux empty set (alpha), empty set (t) , empty set (s) -density in cold plasma. We have simulated electric flux St-density and electroosmotic modeling with antiferromagnetic laminar flow. Finally, we obtain the total optical electric empty set (alpha), empty set (t) , empty set (s) -charge of closed St-surface on spherical Heisenberg group.
查看更多>>摘要：Lithium fluoride (LiF) is one of the best tissue equivalent materials exhibiting good thermoluminescence (TL) properties, however it shows weak optically stimulated luminescence (OSL) response with blue light (470 nm) stimulation. Several research groups are working on improving the OSL properties of LiF phosphor. In an attempt, a thorough investigation on tissue equivalent LiF: Mg,Cu,Na,Si (MCNS) as a possible OSL material has been done in the current work. As the preparation route and particle size can modify the energy levels and optical transitions, the striking improvement is expected by preparing it in nanocrystalline form. The structural and morphological characterization has been done using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The OSL emission is observed in continuous wave mode under blue (460 nm) light stimulation. The OSL decay curve exhibits a significant increase in intensity which is ~2 times higher than LiF based commercial phosphor (TLD-100) irradiated with gamma dose of 0.1 Gy. The phosphor shows a linear dose response in the range of 0.1-20 Gy with almost constant decay rate. The phosphor has shown low residual signal which is good for its repetitive use. The OSL decay curve has been analysed and related parameters such as photoionization cross-section and decay constant are determined. ESR study has been done to identify the defect centres and describing the role of point defects and charge compensators involved in the luminescence process. This reveals the existence of Cu in Cu+ or Cu0 state. Good OSL properties suggests MCNS phosphor has a potential as a OSL dosimeter. The current study adds new knowledge and opens a new window to improve the OSL sensitivity of LiF material.
查看更多>>摘要：Aiming at low security of traditional encryption methods, a new image encryption algorithm based on discrete fractional wavelet transform (DFRWT) and quantum Logistic mapping is proposed in this paper. Firstly, p-order multiscale decomposition is performed for the original image, with DFRWT regarded as decomposition tool. Then the obtained high and low frequency coefficients are shuffled in the time-fractional-frequency domain, followed by an inverse DFRWT to obtain a shuffled image. Finally, XOR operation is carried out between pseudo-random sequence generated by quantum Logistic chaotic and shuffled image, which achieves image diffusion to complete image encryption. Simulation results demonstrate that the algorithm has positive characteristics of large key space, good scrambling performance and quite strong robustness.
查看更多>>摘要：A reflection type linear polarization rotator using L-shaped slot resonator is presented. The proposed metamaterial structure realizes wideband performance (relative bandwidth of 10.35%) due to the overlapping of two nearby resonance modes at 7.54 GHz and 8.03 GHz. The polarization rotation is achieved owing to the structural anisotropy along the two diagonals of the proposed resonator. The polarization conversion ratio (PCR) of the proposed structure is more than 90% in the frequency band of 7.42-8.23 GHz. The proposed structure is competitive in terms of its ultrathin substrate thickness, very low form factor, and wide-angle performance.
查看更多>>摘要：The aim of this study was to evaluate the effect of lens shape towards the light performance from light-emitting diode (LED) based street light. The other consideration taken into account was the effect of different light-emitting surface (LES) shapes on the light distribution. Three sets of experiments were carried out to figure out the shape of lens as well as the shape of LES suitable to be used in the street light application. Optical characterization was carried out using the Goniophotometer (GO-2000) and Integrating Sphere (PCE-200A). DIALux Evo software was used to perform simulation by taking the ME4A road lighting requirement set by Tenaga Nasional Berhad (TNB) as a benchmarking. In comparison, Lens D possessing short rounded rectangular lens demonstrated a better light performance as compared to long rounded rectangular and triangular lenses, owing to the acquisition of lesser light trespass problems. Besides, a better light performance was demonstrated by square-shaped LES as compared to the round-shaped LES due to the presence of large surface area that was able to distribute light evenly. Detailed investigation was presented.
查看更多>>摘要：We propose a scheme that can generate tunable magnomechanically induced amplification in a double-cavity parity-time-(PT-) symmetric-like magnomechanical system under a strong control and weak probe field. The system consists of a ferromagnetic-material yttrium iron garnet (YIG) sphere placed in a passive microwave cavity which is connected with another active cavity. We reveal that ideally induced amplification of the microwave probe signal may reach the maximum value 106 when cavity-cavity, cavity-magnon and magnomechanical coupling strengths are nonzero simultaneously. Besides, we also find the phenomenon of slow-light propagation. In this case, group speed delay of the light can achieve 35 x 10(-5)s, which can enhance some nonlinear effect. Moreover, due to the relatively flat dispersion curve, the proposal may be applied to sensitive optical switches, which play an important role in storing photons and quantum optical chips.
查看更多>>摘要：In this paper, we reported a composite optical fiber probe structure based on a Cu/WS2 coated surface plasmon resonance (SPR) coreless fiber and a microfiber Fiber Bragg Grating (FBG), which can be used for the simultaneous detection of pH and temperature by assembling Polyacrylamide Gel (PAAG) film and Polydimethylsiloxane (PDMS) coating, respectively. The simulation and experimental results show that WS2 nanofilm can effectively enhance the refractive index (RI) sensitivity of 50 nm-Cu film coated optical fiber SPR probe. Due to the swelling ratio of PAAG is regulated by the pH of liquid solution, the sensitivity of pH detection can reach -4.42 nm/pH in the pH range of 1-9. The temperature response of the pH probe is one of the main factors leading to the pH detection error, and the experimental result is as high as 76.60 pm/degrees C in the range of 20-60 degrees C. The temperature sensitivity of the FBG can be increased from 10.4 pm/degrees C to 85.67 pm/degrees C by chemical corrosion and covering PDMS coating for temperature compensation.
NSTL
Elsevier