Array Structure Research Articles

A study on the co-optimization design method of diesel engine in-cylinder combustion performance and steel piston heat transfer characteristics: A new pit array combustion chamber structure

Steel pistons have become the optimal solution for high-performance engines. However, the efficient design and widespread application of steel pistons are constrained by physical parameters such as high density and low thermal conductivity. In this paper, a parameterized structure of pit arrays on the center, bottom, and top surfaces of the combustion chamber was set up by utilizing the high mechanical strength of steel pistons. Subsequently, the diesel engine in-cylinder combustion performance and steel piston heat transfer characteristics were co-optimized for the design. Ultimately, the structure of the researched design with indicated specific fuel consumption and thermal stress control was obtained. The study results show that the top surface mass of the researched design can be reduced by 8.32 g. The researched design can exhibit better combustion and emissions performance. Moreover, the pit structure can allow the fuel to touch the wall with less energy loss, thereby alleviating the problems of fuel accumulation on the wall and wall-adhered combustion. In addition, the maximum thermal stress in the researched design decreases by 15.68 MPa, or 3.93 %, while increasing the highest temperature by only 2.30 °C compared to the original design.

Energy-efficient high-linearity SAR ADC with a unary–binary hybrid capacitor switching method

This study developed a 10-bit 10 MS/s energy-efficient and high-linearity successive approximation register (SAR) analog-to-digital converter (ADC). The design utilized a capacitor array structure employing “3-bit thermometer code + 6-bit binary code” to achieve 10-bit quantization through a Vcm-based three-level capacitor switching scheme. The thermometer codes optimized the switching capacitors of the most significant bits to enhance linearity. Further, a unary and binary code control method was implemented to automatically switch across the remaining unary code capacitors when the differential output of the digital-to-analog converter was below 64 least significant bits (LSB). This method reduces the switching energy by 30% compared to the binary CDAC, while RMSDNL and RMSINL are reduced by 47.50% and 26.08%, respectively. The 10-bit SAR ADC was designed with 0.18μm CMOS technology, and the ADC core occupied an area of 0.077 mm2. At supply and reference voltages of 1.2 V, the ADC achieved differential non-linearity and integral non-linearity values of +0.36/−0.32 and +0.4/−0.37 LSB, respectively, at a sampling frequency of 10 MS/s and with a 1% capacitor mismatch. At an input signal frequency of 4.65 MHz, the ADC achieved a signal-to-noise-and-distortion ratio (SNDR) and spurious-free dynamic range (SFDR) of 60.07 and 80.03 dB, respectively. The ADC consumed a power of 137.36 μW, and the Walden figure of merit was 16.74 fJ/conversion-step.

Four-band tunable narrowband optical absorber built on surface plasmonically patterned square graphene

The square and ring-shaped graphite four-band ultra-narrow-band absorber in this paper achieve perfect absorption. Therefore, the four waves of perfect transmission in the middle infrared band have been achieved, and there are four common values at λ1 = 2471.33 nm, λ2 = 2553.81 nm, λ3 = 2588.4 nm and λ4 = 2661.9 nm. Their ultra-high reflectors are 99.95 %, 96.65 %, 92.87 %, and 97.65 %, respectively, and the average reflective rate is 96.78 %. This is achieved in the graphene array structure of the pattern. Single-layer graphene is due the near-field enhancement has achieved almost perfect absorption. From the characteristics of graphene, a single variable is used to compare the effects of each variable on the efficiency of the absorber. From the perspective of incident light, it can be understood that the absorber can work within a wide range of incident angle to achieve a high absorption rate. The results obtained from the changes in environmental refractive index are more interesting. The structural model in this chapter has a high FOM (Figure of Merit) and can act as a atmospheric refractive index sensor.

Simplified circuit model of novel bypass diode based PV array for circulating current and power loss minimization under partial shading

Purpose This study aims to propose a new connection technique of bypass diode (BD) in photovoltaic (PV) array, which reduces the circulating current (CC) within PV modules as well as conduction loss in partial shaded condition (PSC). Design/methodology/approach Linearized circuit model of PV panel is proposed for calculating the CC and power loss of novel BD arrangements in PV array. From the analysis the best BD arrangement is applied in series parallel, TCT and honeycomb (HC) PV array structure for simulation and hardware verification. The hardware verification is performed in a 3 × 3 PV array, where individual panel capacity is 200 W. Findings The proposed BD arrangement reduces the power loss due to CC under PSC by almost 3% compared to conventional BD structure in a PV array. Originality/value The proposed BD arrangement is simple and useful in large PV power plants to reduce the CC-based extra power loss under PSC.

MIL-88-derived porous carbon rod-supported FePS3 nanosheet arrays for robust sodium storage

Ternary metal phosphorus trisulfide (MPS3) has emerged as an excellent candidate for use as an anode in sodium-ion batteries, characterized by its unique layered structure, easily tunable physicochemical properties, and high theoretical capacity. However, its intrinsic challenges such as low electrical conductivity and susceptibility to fragmentation have led to unsatisfactory rate and cyclic capability. Herein, the intriguing microcomposite structure of porous carbon rod-supported FePS3 nanosheet arrays (FePS3@CR) is ingeniously constructed in situ via the phospho‑sulfurization of MIL-88. FePS3@CR showcases multiple structural advantages, including enhanced electrical conductivity, increased surface area, accelerated electron transfer rate, and mitigated structural stress. These combined benefits endow FePS3@CR with improved rate capability (808.0 and 474.3 mAh g−1 at 0.1 and 10 A g−1, respectively) and cyclic life (94.5 % retention after 1500 loops at 2 A g−1). The assembled full battery also demonstrates robust cycling stability, retaining 94.2 % of its capacity after 1100 loops at 0.5 A g−1. The specific sodium storage process of the FePS3 electrode is investigated through ex-situ structure analysis. This work presents innovative structural designs potentially improving the energy storage performance of MPS3 material system.

Multiple Fano resonances in all-dielectric porous array structures

High Q metasurfaces play an important role in fields such as high-sensitivity sensing and nonlinear optics due to their strong localized electromagnetic field enhancement. Although ultra-high Q resonance has been developed in the field of optics, it is still a challenging task due to the loss of dielectric materials, design and fabrication of nanostructures. In this paper, we have designed an all-dielectric symmetric perforated array structure that supports multiple Fano resonances within the 0–1 THz range and realizes the anapole mode through this array perforation structure. By calculating the phase difference between different modes at the resonance frequencies, we explain the mechanism of the formation of resonance-coupled BIC. The Q-factors of the three modes have been calculated, where the highest Q-value can be up to 2703, it is excited by the MQ. Then, we analyzed the sensing performance and the highest sensitivity can reach 27,000 nm/RIU. Since the metasurface always maintains c_4v symmetry and mirror symmetry, all three resonances are polarization independent. The proposed metasurfaces can be applied to light-matter interactions, enhanced nonlinear response, and sensing.

TEA Guiding Bimetallic MOF with Oriented Nanosheet Arrays for High-Performance Asymmetric Supercapacitors.

The development of supercapacitors with ultrahigh power density, high energy density, and compatible integration for wearable microelectronic devices is significant but challenging. Herein, a bimetallic metal-organic framework (Ni/Co-MOF) with oriented nanosheets was obtained via triethylamine (TEA) guiding using a hydrothermal treatment, in which the TEA guides the vertically oriented array structures of the Ni/Co-MOF and ensures a fast ion/electron transmission path. Subsequently, an asymmetric supercapacitor was rationally designed by applying the bimetallic MOF cathode and an activated carbon (AC) anode. The obtained Ni/Co-MOF sample offers a high storage capacity of 2034 F g-1 at 0.5 A g-1 by harnessing the optimized Ni/Co-MOF with uniformly oriented nanosheet arrays. The constructed asymmetric supercapacitors exhibited a large voltage window of 1.4 V in 3.0 M KOH and an outstanding energy density of 29.5 Wh kg-1 at a power density of 199.1 W kg-1 was obtained, with a remarkable capacitance retention of 89% after 2000 cycles.

Fabrication of Ordered Nanohole Arrays by Anodization of Sn Substrates with Ordered Dimple Patterns Formed Using Porous Alumina Template

Abstract Sn thin films with ordered concave patterns were formed by the thermal deposition of Sn onto an anodic porous alumina template and peeling off the Sn thin film from the template. Ordered nanohole array structures with uniformly sized pores were obtained by anodizing the obtained Sn thin film. This is because each shallow concave formed on the Sn thin film acts as an initiation site for pore development during the initial anodization stage. On the basis of this process, large-area anodic Sn oxide films with ordered nanohole array structures were obtained using a large-area anodic porous alumina template. The interpore distance of the nanohole array structure in the anodic Sn oxide film can also be controlled by changing the structure of the anodic porous alumina template. The obtained anodic Sn oxide film with an ordered nanohole array structure is expected to be used for various applications, such as batteries, sensors, and solar cells.

Chain-Like Pentanuclear Complexes: Syntheses, Crystal Structures and Long-Range Electronic Interactions of Cyanido-Bridged M2Ru3 (M=Fe, Ru).

In this work, we report the design and synthesis of two chain-like pentanuclear cyanido-bridged complexes trans-[Ru(bpy)2(μ-CN)2][cis-Ru(bpy)2(μ-NC)M(dppe)Cp*]2[PF6]4 (M=Fe, 14+; M=Ru, 24+) and the electronic communication properties of their oxidized products 1m+ (m=6, 7, 8) and 2n+ (n=5, 6, 7, 8). The single-crystal X-ray diffraction analysis of 1m+ (m=4, 6, 7) and 24+ show that 14+ and 24+ possess a Z-type array structure, 17+ is a U-type one, and 16+ exhibits both the types. The investigations indicate that both 1 and 2 show an extraordinarily strong electronic interaction between the two side Ru across the central NC-Ru-CN, leading to the formation of a fully delocalized cyanidometal Ru-Ru-Ru bridge for both three-electron oxidized states 17+ and 27+. Moreover, it should be noted that in 1 there exists no electronic interaction between the two terminal Fe ions. Upon substitution of Fe by Ru, however, 2 exhibits an electronic interaction between the two terminal metal ions across the trinuclear cyanidometal CN-Ru-NC-Ru-CN-Ru-NC bridge which is up to 20 Å.

Curvature-Compensated Bandgap Voltage Reference with Low Temperature Coefficient

Resistance errors in bandgap reference (BGR) circuits often cause deviations in design indicators, and it is true that utilizing various compensation techniques mitigates the impact of resistance errors. In this paper, an original BGR circuit with 180 nm BCD processing is presented, which uses an improved high-order compensation and curvature compensation. The proposed BGR contains four main blocks, including a start-up stage, a first-order temperature compensation stage, a high-order temperature compensation stage, and a curvature compensation stage. Meanwhile, a trimming resistor array structure is designed to revise the temperature coefficient (TC) deviation of the test output voltage from the theoretical design value. Through wafer-level laser trimming technology, the measurement results are achieved with very little difference from the theoretical design value. The proposed BGR provides a stable reference voltage at 1.25 V with a low TC and strong power supply rejection (PSR). Within temperatures ranging from −45 °C to 125 °C, the measured TC shows an optimal value at 4.2 ppm/°C and the measured PSR shows −100 dB.

Synthetic Augmented L-shaped Array design and 2D Cramér-Rao bound analysis based on Vertical-Horizontal Moving Scheme

This paper introduces an innovative approach to enhance the effectiveness of the L-shaped array using synthetic aperture processing. Through the implementation of the Vertical-Horizontal Moving Scheme (VHMS), a novel 2D array structure called the Synthetic Augmented L-shaped Array (SALA) is developed, featuring varied element spacing along the x and y axes of a 1D linear array. Comparative analyses demonstrate that the SALA achieves a larger difference coarray and higher degrees of freedom compared to arrays with an equivalent number of physical elements. The paper also provides a comprehensive derivation of the Cramér-Rao Bound (CRB) for 2D moving arrays, with detailed analyses of its conditions and properties. Simulation results highlight the SALA's superior capabilities in detecting multiple sources and providing precise 2D direction of arrival estimation, along with a lower CRB, indicating its potential for practical implementation in diverse scenarios.

Ultra-broadband perfect solar absorber based on V2O5−TiN−V2O5 nanodisc and TiN nanopillar array structures

Ultra-broadband perfect solar absorber based on V2O5−TiN−V2O5 nanodisc and TiN nanopillar array structures

A Porphyrin-Based MOF Thin Film with Oriented Nanosheet Arrays for Optimizing a Nonlinear Optical Response.

Developing two-dimensional (2D) hybrid nanosheet arrays integrating inorganic and organic components is highly significant for third-order nonlinear optical (NLO) applications. Herein, an oriented 2D porphyrin-based MOF (ZnTPyP(Co)) thin film composed of vertically stacked ultrathin nanosheets was fabricated via the liquid-phase epitaxial (LPE) layer-by-layer (LBL) method. The prepared ZnTPyP(Co) thin film exhibits an outstanding third-order NLO response with a high third-order nonlinear susceptibility of ∼2.63 × 10-7 esu, which is ascribed to the hybrid nanosheet array structure. Additionally, experimental Z-scan measurement and theoretical calculations also demonstrate that the substitution of Co metal ions in the porphyrinic core can increase the level of delocalization of the porphyrinic group and contribute to the material's enhanced NLO properties. These findings not only provide new film candidates for NLO application but also highlight the potential of 2D MOF nanosheets in advanced optical devices.

Quasi-2D and 3D phase-field simulation studies of polar vortex domain structures for high-density domain engineering

Phase-field simulations were performed on the polar vortex array structure appearing in the SrTiO3/PbTiO3/SrTiO3 heterostructure to investigate the Kittel law relationship (w ∝ d1/2) between the vortex array period (w) and the PbTiO3 ferroelectric layer thickness (d). Quasi-two-dimensional simulation results show that the equilibrium period can be determined from the relationship between the size of the simulation box and the total free energy density and that the obtained period obeys the Kittel law. However, three-dimensional simulation results show that the polar vortex arrays are not homogeneous in the direction perpendicular to the vortex plane. In the pure vortex state, no obvious correlation exists between the simulation size and energy because of the dislocations caused by the vortex period mismatch. However, in the mixed state with ferroelectric a1/a2, the vortex domains exhibit equilibrium periods that satisfy the Kittel law relationship because of the confinement effect caused by phase separation. Further study of the confined vortex domains in these mixed states and the vortex domains of finite size due to mismatched dislocations are expected to enable domain engineering of higher domain densities.

Achieving Dendrite-Free Lithium Metal Batteries by Constructing a Dense Lithiophilic Cu1.8Se/CuO Heterojunction Tip.

Lithium (Li)metal batteries (LMBs) have garnered widespread attention due to their high specific capacity. However, the growth of lithium dendrite severely limits their practical applications. Herein, a novel strategy is proposed to regulate the overall potential strength and lithium ions (Li+) concentration on the surface of the current collector by utilizing densely distributed tip effects. This concept is exemplified through the construction of lithiophilic Cu1.8Se/CuO heterojunction needle array on the Cu foil, ultimately achieving dendrite-free lithium deposition. Based on the simulation in COMSOL multiphysics and experimental research, this design is demonstrated to enrich Li+ on the current collector surface, delay the formation of space charge regions, and mitigate the growth of lithium dendrites. Additionally, a built-in electric field (BIEF) triggered by the heterointerface between Cu1.8Se and CuO further alleviates the Li+ concentration gradient on the electrode surface, achieving uniform bottom-up deposition of Li within the array structure. Consequently, the symmetrical cell exhibits an ultra-long cycle life of 2400h (1mAcm-2, 1mAhcm-2) with an extremely low overpotential of 13mV. Furthermore, full batteries using LiFePO4 as the cathode exhibit superior cycle stability and rate performance. This study presents a promising approach for designing dendrite-free current collectors in LMBs.

Dual magnetoelectric antenna array with enhanced bandwidth and sensitivity for low-frequency communications

The magnetoelectric coupling effect demonstrated immense potential for miniaturizing antenna applications. However, due to the resonant nature of magnetoelectric (ME) antennas, their bandwidth tended to be relatively narrow. To address this limitation, our study introduced an array design based on coupled ME antennas. A tri-layer FeGa–PZT8–FeGa laminate structure was employed to construct the ME antennas, which utilized inter-array coupling to broaden the frequency range. Both the central frequency and sensitivity of the array structure were theoretically analyzed, and two methods for extending the frequency were proposed. By coupling two ME antennas of similar frequency in the series mode, the arrayed ME antennas exhibited enhanced sensitivity, increasing from 0.225 and 0.247 to 0.413 mV/nT, and an expanded bandwidth from 0.92–1.03 to 1.4 kHz, indicating improved performance through combined configuration. On the other hand, by coupling two ME antennas of different frequencies together in the series mode, a dual-frequency (97.8/98.97 kHz) ME antenna array was formed. The communication capabilities of the ME antenna array under weak magnetic fields were demonstrated using amplitude shift keying and frequency shift keying modulation methods. The designed array of ME antennas elevated low-frequency communication performance and possessed excellent magnetic field detection capabilities, thereby offering a cost-effective technological pathway for bioelectronic and marine communication design.

Influencing factors of self-aligned imaging in near-field lithography for the Fabry–Perot cavity effect

In near-field lithography, the Fabry–Perot (F-P) cavity enhancement effect can significantly improve image quality and resolution. This paper considers changes in the refractive index and air distance in self-aligned imaging. Simulation results demonstrate that the Fabry–Perot resonator effect achieves effective self-alignment in 3D imaging. The proposed structure builds on traditional near-field imaging structures and F-P resonator research, suggesting a Cu/SiO2 structure as the front layer. Rigorous coupled wave analysis (RCWA), finite element method (FEM), and finite-difference time-domain (FDTD) methods were employed to verify the self-alignment effect on single gratings and rectangular hole arrays. The results indicate that the self-alignment lithography method based on the F-P effect not only enhances lithography contrast and normalized image log-slope (NILS) but also shows robust performance against variations in air distance and complex refractive index. Notably, for the rectangular aperture array structure, with changes in air distance and complex refractive index within a certain range, the NILS remains stable above 2.8, and the contrast stays near 0.70. These simulation results confirm that the F-P resonator-based scheme is viable for plasma imaging lithography with small critical dimensions.

Enhanced microwave absorption of sandwich panels with magnetized carbon fiber corrugated array reinforced PMI foam core

AbstractIntegrating periodic array structures made of metal wires or conductive inks into the foam core of electromagnetic (EM) wave absorbing sandwich panels can significantly improve broadband absorption performance. However, the complex fabrication process and poor corrosion resistance of these materials limit their practical applications. This work innovatively introduces magnetized carbon fiber (CF) into PMI foam, simultaneously achieving broadband absorption and lightweight characteristics of the sandwich structure through the design of array structure and fiber bundle geometry. Simulation analysis compared the EM absorption performance of sandwich panels with carbonyl iron powder (CIP)/CF tape and helical twisted CIP/CF rope corrugated arrays, determining the optimal array structure parameters, which were then experimentally validated. The experimental results align with the simulations, showing that CIP/CF rope corrugated arrays with an amplitude of 10 mm, a cycle length of 15 mm, and an array spacing of 15 mm provide optimal absorption performance, with a reflection loss below −10 dB across the 9–18 GHz frequency range and a maximum absorption of −33.9 dB at 17 GHz. Finally, the absorption mechanism of these sandwich structures is discussed, highlighting how the synergistic effects between the electromagnetic properties and structural morphology of CIP/CF enhance the absorption performance of the EM absorbing sandwich panel.

Flexible Au@Ag/PDMS SERS imprinted membrane combined with molecular imprinting technology for selective detection of MC-LR

In this study, a core–shell structured bimetallic nano-cube, Au@Ag NCs, was prepared by seed-mediated growth procedure. The array structure of Au@Ag NCs was achieved at the interface through the autonomous assembly technique at the three-phase boundary. Employing polydimethylsiloxane (PDMS) as a flexible carrier, the array structure was effortlessly transferred to the PDMS membrane, bypassing the need for rigid substrates through a simple “pasting” method. This yielded a highly flexible and transparent SERS substrate with an array structure (Au@Ag NCs/PDMS membrane, AAP). In order to promote the selective detection property to the practical samples, molecularly imprinted polymers (MIPs) were coated on the surface of membrane to prepare the imprinted membrane (Au@Ag NCs/PDMS-MIMs, AAP-MIMs). It was demonstrated from the results that the AAP-MIMs exhibited high SERS sensitivity, stability, and uniformity. Furthermore, the flexible substrate possessed commendable mechanical strength, and facilitated the detection of analytes on irregular surfaces. In summary, this substrate held promising potential for practical on-site detection and analysis of specific target substances.

PV Array Reconfiguration for Global Maximum Power Optimizing under Partial Shading Conditions based on PV Switched System

Background: Due to the partial shading effects on different photovoltaic (PV) modules in a PV array, PV module operating conditions are inconsistent, and PV array output power is significantly reduced. Although the maximum power point (MPP) of a non-uniform irradiance PV array can be observed through global maximum power point tracking (GMPPT), no evaluation of the array's energy potential has been done. Objective: One of the most effective solutions to overcome the negative effects of partial shading in PV systems is the PV array reconfiguration process. To optimize the electrical structure of the PV array as the PV modules are partially shaded in a non-uniform manner, this study proposes a promising technique for dynamic reconfiguring a PV array in order to improve the extracted maximum power from a PV array under partial shading conditions (PSC). Methods: PV modules are rearranged by iteratively sorting them to allow the PV array with nonuniform irradiance to produce as much power as possible. This is conducted by applying a switching matrix to implement a PV-switched system approach. The proposed system with different PV array dimensions (e.g., 3×4, 4×6, and 5×8) is assessed in order to validate the proposed algorithm. A MATLAB/Simulink PV array developed model is used to find the global maximum power point for the different PV array dimensions in both pre-reconfiguration and post-reconfiguration states. Results: A detailed numerical comparison of the extracted power from the proposed system has been provided. Conclusion: The results show that the proposed system has the potential to extract the exact global maximum power for a PV-switched system under PSC, irrespective of array dimensions, according to simulation results.