Optical and Quantum Electronics最新文献

Industrial Wireless Sensor Networks (IWSN) is the cornerstone of the factories of the future. The massive volumes of heterogeneous data generated from large-scale IWSNs still pose challenges to the establishment of predictable, deterministic, and real-time transmission scheduling. One of the major obstacles in wireless sensor networks (IWSNs) is the reduction of collisions caused by adjacent nodes transmitting simultaneously over a single channel. The Optimized TDMA Framework for Optimized Channel Interference Mitigation Algorithm (OCIMA) has been developed in order to prevent transmission collisions. Specifically, the suggested TDMA approach significantly reduces the collision during the data transmission, while simultaneously minimizing the high priority packets transport latency. The nodes are first positioned throughout the experimental area at random. Using the Self-Adaptive Affinity Propagation Clustering (SAAPC) Algorithm, the deployed nodes are clustered to form clusters, with a cluster head selected. Self-adaptive affinity propagation consists of the initial phase, setup phase, and communication phase. After clustering, channel interference can be avoided using the TDMA approach combined with the Gazelle Optimization Algorithm (GOA). To prevent data collisions, each network cluster is given time slots via the TDMA mechanism. The optimal practicable performance of TDMA can be attained by choosing a sufficient amount of time slots for the complete data transfer. For that, GOA optimization is developed to choosing the optimal timeslots. According to the simulation analysis, the OCIMA technique that was created which have 12.4 J residual energy, 94% packet delivery ratio, and 986 s network lifetime. Thus, the proposed approach is the better choice for avoiding the mitigation of TDMA during data transmission.

The influence of the nonlinear response of the interface on the localized state formation near at the boundary between medium with Kerr nonlinearity an exponential graded-index medium is analyzed. The linear and nonlinear responses of the interface are taken into account. The cases of self-focusing and defocusing nonlinearities of the Kerr medium are considered. Exact analytical solutions describing the asymmetrical spatial profiles of localized states and analytical solutions to dispersion equation in different cases are found. The intensity at the interface reduces in the case a defocusing nonlinear response of the interface and it enlarges in the case a self-focusing nonlinear response of the interface with an increase in the localization energy. The spatial distribution of localized states with two asymmetrical maxima can arise with a relatively small value of the characteristic width of an exponential graded-index medium corresponding to the ground state characterized by no more than one maximum in the graded-index medium. The appearance of the second maximum is possible in the case of contact only between a self-focusing medium and the graded-index medium and is due solely to the presence of a nonlinear response of the interface. The localized states with the spatial profiles attenuating with oscillations in the graded-index medium are found with a significant increase in the characteristic width of a graded-index medium.

This article explores the reinforcement of the chief characteristics of the polymer blends made of polyvinyl alcohol (PVA) and polyvinylidene fluoride (PVDF) via incorporation of ZnO (zinc oxide) nanofiller. The resulting PVA/PVDF/ZnO polymer nanocomposites were fabricated by the solution casting approach and characterized by key techniques such as XRD, FESEM, UV-Vis-NIR photo-spectrometer, impedance analyzer and FTIR spectrometer to examine the enhancement in structural parameters, surface morphology, optical and electrical parameters, and mechanism of functional groups. respectively. By optimizing and enhancing the wt% of ZnO nanoparticles, the resulting nanocomposites demonstrate improved structural (increase in crystalline size from 63 nm to 70 nm, reduction in dislocation density from 9.61 × 10^− 5 to 6.49 × 10^− 5 m^− 2) and optical parameters (reduction in optical bandgap from 5.02 eV to 4.44 eV, increase in refractive index and Urbach energy from 1.98 to 2.10 and 1.5 to 4.0 eV, respectively); and dielectric performance (augmentation in dielectric constant and ac conductivity from ~ 12 to 60 and 0.003 to 0.009 S/mm, respectively) making them appropriate for a broad range of industrial applications. In FTIR spectra, the transmittance peaks at 880 cm⁻¹ and 833 cm⁻¹ indicate the -C-C-C chain characteristic of PVDF, while peaks at 1402 cm⁻¹ and 2920 cm⁻¹ correspond to -CH₂ groups in both PVA and PVDF. Additionally, peaks at 1068 cm⁻¹ and 1704 cm⁻¹ relate to -C-O and -C = O stretching, and the broad peak from 3500 cm⁻¹ to 3800 cm⁻¹ represents hydroxyl groups, with intensity increased by ZnO nanofiller. The uniform dispersion of ZnO within the PVA/PVDF polymer blends plays a key role in reinforcing the interfacial bonding between the polymers, leading to superior structural integrity and enhanced recyclability. This approach offers a sustainable pathway for the progress of high-performance polymeric nanocomposites with potential applications in electronics.

This article proposes a new Ultra-Violet (UV)-C Light emitting Diode (LED) structure based on orderly aligned Quaternary Nitride alloy based specially-designed quantized quantum barrier. In this article, we theoretically investigate the performance such as internal quantum efficiency (IQE), efficiency droop etc. of proposed structure and also compare it with the reference UV-C LED structure. In this proposed structure, there is no sudden potential barrier as in case of reference structure because of the strain compensation provided by the quantized periodic Superlattice-Al_xIn_yGa_(1-x–y)N/ Al_aGa_bN quantum barrier. Active region epilayer crystal orientation balanced by introducing ‘In' molar content in alternate sub-layers of quantum barrier (QB). This allows for stronger carrier confinement in the active region, which enhances IQE to 72% from 32% (reference structure) and reduction in efficiency droop from 11% to 0.05% at current density of 200 A-cm⁻². The variation in the density of states (DOS) for carrier allocation due to strain balance in the quantum barrier compared to the quantum wells (QW) is responsible for the significant increase in the electro-optical efficiency of the light emitting device.

High dense cadmium lead-borate glasses with nominal compositions of (75-X)B₂O₃-XPbO-5Na₂O-10CdO-10ZnO: X = 5–20 mol% in steps of 5 were fabricated via the melt quenching technique. The physical features and the capability of applying the prepared glasses as γ-ray and fast neutron shields have been investigated. The density (D_s) values increased from 4.820 g.cm⁻³ to 5.664 g cm⁻³ as PbO content increased from 5 to 20 mol% in the glass network. The polaron radius (r_p) increased, while the field strength (F) reduced as PbO content increased. The boron ion concentration (N_B) of the investigated glasses decreased from 2.231 × 10²² (ions.cm⁻³) to 1.503 × 10²² (ions/cm³). The inter-ionic distance (r_i) values increased from 3.551 to 4.051 A^o. Values of the packing density (P_d) decreased from 0.888 to 0.695. The free volume (V_f) enhanced from 2.105 to 6.698 g mol⁻¹ cm⁻². The sample BPNCZPb-20 possessed the highest exposure (EBF) and energy absorption (EABF) buildup factors values at 1– 40 MFP among all investigated glasses. The half- value layer (HVL_FCS) and the relaxation length (λ_FCS) values were the lowest for the BPNCZPb-5 glass sample. Therefore, the sample coded as BPNCZPb-20 can be considered as γ-ray shield, but BPNCZPb-5 glass can be used as a neutron shield.

In this article, a lead-free structure FTO/TiO₂/NH₃(CH₂)₂NH₃MnCl₄/spiro-OMeTAD/Au is investigated using SCPAS-1D simulator. Initially, impact of absorber thickness on performance is thoroughly examined and found 900 nm thick absorber solar cell superiuses performer (open circuit voltage = 1.18 V, short circuit current density = 24.47 mA/cm², fill factor = 70.88%, power conversion efficiency = 19.70%). Further, numerous inorganic materials are investigated through lattice mismatching ratio as substitute of organic hole transport layer and CZTSe as the most adequate materials for enhancing both efficiency and stability owing to minimal lattice mismatching, easy synthesis, efficient charge transport characteristics and superior chemical stability. Serval metallic materials like Cu, Fe, C, W, Ni and Pd are used as back contacts, are also examined with an aim of replacing the expensive Au and it is found that the proposed structure offers highest efficiency with Pd i.e., 31.60% (V_oc = 1.13 V, J_sc = 32.94 mA/cm² and FF = 84.55%). Additionally, the effect of defects density of absorber and temperature on device performance are also analysed and observed both factors adversely affects device performance. So, their values kept minimum for achieving optimal efficiency. The simulated results also illustrated in J-V and quantum efficiency (QE) curves. These optimised results obtained in present study are also compared with previously reported results. The results extracted from this simulation may play a potent role in the development of eco-friendly and efficient solar technology.