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This paper presents a low-complexity multi-size circular-shift network (MCSN) structure for 5th-generation (5G) New Radio (NR) quasi-cyclic low-density parity-check (QC-LDPC) decoders. In particular, a fine-coarse approach-based multi-size cyclic shift network, which decomposes the cyclic shift size into fine part and coarse part, is introduced. The proposed MCSN structure is composed of a pre-rotator performing the fine part of the cyclic shift, and a main rotator executing the coarse part of the cyclic shift. In addition, a forward routing circular-shift (FRCS) network, which is based on the barrel shifter and the forward routing process is presented. The proposed switch network is able to support all 51 different submatrix sizes as defined in the 5G NR standard through an efficient forward routing switch network and help reduce the hardware complexity using a cyclic shift size decomposition method. The proposed MCSN is analyzed, and indicates a substantial reduction in the hardware complexity. The experimental results on TSMC 65-nm CMOS technology show that the proposed MCSN structure for 5G NR LDPC decoder offers an area saving up to 56.75% compared to related works in the literature.

Optical signal processing (OSP) technology is a crucial part of the optical switching node in the modern optical-fiber communication system, especially when advanced modulation formats, e.g., quadrature amplitude modulation (QAM), are applied. However, the conventional on–off keying (OOK) signal is still widely used in access or metro transmission systems, which leads to the compatibility requirement of OSP for incoherent and coherent signals. In this paper, we propose a reservoir computing (RC)-OSP scheme based on nonlinear mapping behavior through a semiconductor optical amplifier (SOA) to deal with the non-return-to-zero (NRZ) signals and the differential quadrature phase-shift keying (DQPSK) signals in the nonlinear dense wavelength-division multiplexing (DWDM) channel. We optimized the key parameters of SOA-based RC to improve compensation performance. Based on the simulation investigation, we observed a significant improvement in signal quality over 10 dB compared to the distorted signals on each DWDM channel for both the NRZ and DQPSK transmission cases. The compatible OSP achieved by the proposed SOA-based RC could be a potential application of the optical switching node in the complex optical fiber communication system, where incoherent and coherent signals meet.

Clos-network switches have attracted a lot of attention because of their modularity and scalability. However, out-of-sequence problems weigh heavily against the application of buffered Clos-network switches. A space-memory-memory (SMM) Clos-network switch is proposed in this study which is able to provide in-sequence service. There are two features in the proposed switch which are different from the previously proposed schemes. First, two-stage load-balanced Birkhoff-von Neumann (LB-BvN) switches are adopted for each second-stage module. Second, no inter-stage matching is needed. The key idea to provide in-order cell delivery in the proposed SMM Clos-network switch is that cells belonging to the same flow will experience the identical delay when passing through the LB-BvN switches at the second stage, and arrive at their destined third-stage module in order. Each switching module operates independently, which makes the proposed SMM Clos-network switch practical to implement in hardware. Simulations show that the proposed switch can achieve high performance under both Bernoulli and Bursty arrival traffic.

Benefiting from their good mechanical and electrical properties, epoxy resin materials are widely utilized in the field of high-voltage electrical insulation devices. However, with the increase in voltage levels of equipment, the epoxy resin materials used for insulating pull rods in high-voltage electrical equipment are facing increasingly severe challenges. This study enhanced the mechanical and insulating properties of epoxy resin materials by molecular structure regulation, composite incorporation and formula optimization. The tensile strength, bending strength and impact strength of the epoxy resin materials with molecular structure regulation increased by 20.6%, 8.5% and 42.1%. The breakdown strength successfully increased from 27.6 kV/mm to 29.9 kV/mm. After combining with the modified Al[sub.2]O[sub.3] nanofillers, the breakdown strength, surface resistivity and volumetric resistivity of the composite further improved to 35.8 kV/mm, 2.7 × 10[sup.16] Ω and 5.8 × 10[sup.17] Ω·cm. The insulating pull rod prepared by this method achieved a flashover voltage of 18.5 kV, meeting the requirements for both insulating and mechanical performance of a prototype of 200 kV high-voltage direct current floor tank-type high-speed mechanical switch. This study can provide important support for the optimization of epoxy resin material formulation design and the development of epoxy-resin-insulating pull rods.

By using the method of high-temperature solid-phase reaction, the new piezoceramic SrBi[sub.2]Nb[sub.2-2x]WxSnxO[sub.9] was obtained, where partial substitution of niobium (Nb) atoms with Sn[sup.4+] and W[sup.6+] atoms in the compound SrBi[sub.2]Nb[sub.2]O[sub.9] occurred in the octahedra of the perovskite layer (B-position). X-ray diffraction investigations showed that these compounds are single-phase SrBi[sub.2]Nb[sub.2-2x]WxSnxO[sub.9] (x = 0.1, 0.2) and two-phase SrBi[sub.2]Nb[sub.2-2x]WxSnxO[sub.9] (x = 0.3, 0.4), but all of them had the structure of Aurivillius-Smolensky phases (ASPs) with close parameters of orthorhombic unit cells. It corresponded to the space group A21am. The temperature dependences of the relative permittivity ε/ε[sub.0] and the tangent of the dielectric loss angle tan d were defined at various frequencies. It was found that doping SrBi[sub.2]Nb[sub.2-2x]WxSnxO[sub.9] (x = 0.1) improved the electrophysical properties of the compound: losses decreased, and the relative permittivity increased. This result was obtained for the first time. Moreover, a new result was obtained that indicated an improvement in the electrophysical properties of SrBi[sub.2]Nb[sub.2]O[sub.9] using the chemical element Sn (tin). This refutes the previously existing opinion about the impossibility to use Sn as a doping element.

Femtosecond fiber lasers are widely utilized across various fields and also serve as an ideal platform for studying soliton dynamics. Bound-state solitons, as a significant soliton dynamic phenomenon, attract widespread attention and research interest because of their potential applications in high-speed optical communication, all-optical information storage, quantum computing, optical switching, and high-resolution spectroscopy. We investigate the effects of pump power variations on the formation of mode-locked solitons and bound-state solitons in a femtosecond fiber laser with a Cr[sub.2]S[sub.3] saturable absorber (SA) through numerical simulations while observing the transition, formation, and break-up process of bound soliton pulses. By optimizing the cavity structure and adjusting the net dispersion, the mode-locked soliton is obtained based on this SA. This is the narrowest solitons produced by this SA to date, exhibiting the smallest time-bandwidth product. Moreover, stable double-bound solitons and unique (2 + 1) triple-bound solitons are successfully obtained. The diverse bound-state solitons not only demonstrate the excellent nonlinear absorption properties of Cr[sub.2]S[sub.3] as a saturable absorber but also expand the scope of applications for Cr[sub.2]S[sub.3] saturable absorbers in fiber lasers.

Quantum materials have tremendous potential for disruptive applications. However, scaling devices down has been challenging due to electronic inhomogeneities in many of these materials. Understanding and controlling these electronic patterns on a local scale has thus become crucial to further new applications. To address this issue, we have developed a new optical microscopy method that allows for the precise quasi-continuous filming of the insulator-to-metal transition in VO­[sub.2] with fine temperature steps. This enables us to track metal and insulator domains over thousands of images and quantify, for the first time, the local hysteresis properties of VO­[sub.2] thin films. The analysis of the maps has allowed us to quantify cycle-to-cycle reproducibility of the local transitions and reveals a positive correlation between the local insulator–metal transition temperatures T­[sub.c] and the local hysteresis widths ΔT[sub.c]. These maps also enable the optical selection of regions of high or low transition temperature in combination with large or nearly absent local hysteresis. These maps pave the way to understand and use stochasticity to advantage in these materials by picking on-demand transition properties, allowing the scaling down of devices such as optical switches, infrared microbolometers and spiking neural networks.

Lead-free K[sub.0.5]Bi[sub.0.5]TiO[sub.3] (KBT) ceramics with high density (~5.36 g/cm[sup.3], 90% of X-ray density) and compositional purity (up to 90%) were synthesized using a solid-state reaction method. Strongly condensed KBT ceramics revealed homogenous local microstructures. TG/DSC (Thermogravimetry-differential scanning calorimetry) techniques characterized the thermal and structural stability of KBT. High mass stability (>0.4%) has proven no KBT thermal decomposition or other phase precipitation up to 1000 °C except for the co-existing K[sub.2]Ti[sub.6]O[sub.13] impurity. A strong influence of crystallites size and sintering conditions on improved dielectric and non-linear optical properties was reported. A significant increase (more than twice) in dielectric permittivity (ε[sub.R]), substantial for potential applications, was found in the KBT-24h specimen with extensive milling time. Moreover, it was observed that the second harmonic generation (λ[sub.SHG] = 532 nm) was activated at remarkably low fundamental beam intensity. Finally, spectroscopic experiments (Fourier transform Raman and far-infrared spectroscopy (FT-IR)) were supported by DFT (Density functional theory) calculations with a 2 × 2 × 2 supercell (P4[sub.2]mc symmetry and C4v point group). Moreover, the energy band gap was calculated (E[sub.g] = 2.46 eV), and a strong hybridization of the O-2p and Ti-3d orbitals at E[sub.g] explained the nature of band-gap transition (Γ → Γ).

This paper presents an RF switch chip with a wide operating bandwidth from 6 to 18 GHz, designed for RF front-end applications in mobile communications. A series-parallel topology combined with a stacked transistor structure was employed to improve power handling while maintaining low insertion loss and high isolation. To further optimize isolation and return loss, LC resonant circuits were introduced by utilizing off-state transistors as capacitive elements. Compared to existing designs, the proposed switch achieved an improved trade-off between bandwidth, power capacity, and port performance. Measurement results showed insertion loss below 1.917 dB, isolation above 38.839 dB, return loss better than 13.075 dB, and 1 dB input compression point above 32 dBm at 12 GHz, confirming the effectiveness and novelty of the broadband design.