Dimensional Array Research Articles

Dispersion-induced Q -factor enhancement in waveguide-coupled surface lattice resonances

Diffractively coupled nanoparticle arrays are promising candidates for helping to flatten many photonic devices such as lasers, lenses, and metrology instruments. Their performance, however, is directly linked with the size of the metasurfaces, limiting their applicability in nanophotonic applications. Here, we dramatically reduce array sizes of high-Q factor metasurfaces by utilizing strongly dispersive media. The effect is demonstrated by theoretically and numerically studying periodic arrays of plasmonic nanoparticles embedded inside Bragg-reflector waveguides. We demonstrate array dimensions reduction up to two orders of magnitude while still achieving ultrahigh-Q factors in excess of 104. Published by the American Physical Society 2024

A Set of Models for Device Positioning in Sixth Generation Networks. Part 2. Review of Algorithms and Accuracy Assessment

Relevance. This work is the second part of a series devoted to the study of a set of positioning models in sixth-generation terahertz networks and solves the problems of systematizing algorithms and assessing the accuracy of determining the location of a user device depending on the configuration and size of the antenna array at the base station.Purpose. Within the framework of the scientific problem of searching for means of achieving decimeter accuracy of coordinate estimates, outlined in the first part of the cycle, the analysis of accuracy assessment models, a review of algorithms and ways of their optimization, as well as a numerical experiment, performed in this study serve the purpose of justifying the configuration and dimensions of the antenna array used at the base station.The research method is an analytical review of the state of the problem based on current scientific publications, conceptual modeling, categorical approach, expert combination, comparative analysis, formalization, mathematical and simulation modeling.Solution / results. The paper presents models for assessing the accuracy of positioning in 6G terahertz networks, formalizes the relationship between primary measurements and coordinate estimates for multi-position and single-position positioning in the near and far zones. It provides an overview of algorithms for geometric positioning and positioning with training for cases of one-stage and two-stage processing; analyzes the specifics of implementing algorithms for simultaneous tracking and map construction. It provides an analysis of the features of optimizing algorithms in offline and online modes. Simulation modeling is used to assess the accuracy for a scenario of territorial distribution with direct visibility and ideal synchronization.Novelty. Using simulation modeling tools, the achievement of decimeter accuracy of coordinate and orientation estimates of 1° in the terahertz range for a far-field model using a 1 GHz band and a composite antenna array of more than half a thousand elements has been scientifically substantiated.The theoretical significance lies in establishing the dependence of the accuracy of coordinate and orientation estimates of the device on the configuration and dimensions of the antenna array at the base station.The practical significance of the developed simulation model lies in the numerical justification of the limits of device positioning accuracy in sixth-generation networks depending on the antenna array used at the base station for a given scenario.

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.

Strong laws of large numbers for weighted sums of 𝑑-dimensional arrays of random variables and applications to marked point processes

The aim of this paper is twofold. Firstly, we give equivalent conditions for the convergence of each of three series in the Kolmogorov-type three-series theorem for random variables with multidimensional indices. Our results extend the results of Sung (2011) for multi-indexed sums. Secondly, by using these results, we develop almost sure convergence for weighted sums of d d -dimensional arrays of random variables. We obtain the Jajte type strong law of large number for these arrays of random variables. As an application, the almost sure asymptotic behavior for sums generated by marked point processes is investigated.

Growth mechanism and SERS effect of Ag nanowire arrays prepared by solid-state ionics method

Solid-state ionic method has attracted more and more attention due to its simple operation and controllable preparation, but its growth mechanism is still uncertain. In this work, Ag nanowire (Ag NW) arrays prepared by solid-state ionics method at 5 μA impressed currents using fast ionic conductor RbAg4I5 films and different metal electrodes were reported. The conduction mode of Ag+ in RbAg4I5 films, the growth mechanism of Ag NW arrays prepared by solid-state ionics method and the effect of microscopic morphology on surface-enhance Raman scattering (SERS) performance were investigated. The results show that Ag nanoparticles (Ag NPs) with diameters from 40 nm to 70 nm were attached to the surface of Ag NW arrays with diameters of 80–150 nm prepared with different metal electrodes, which lead to Ag NW arrays have high surface roughness. The conduction velocity and stability of Ag+ in RbAg4I5 films are closely related to the morphology of Ag NW arrays. The irregular electrode interface and apical growth advantage resulted in the fractal dimension of Ag NW arrays prepared with Ag electrodes is 1.69 due to macroscopic dendritic structure. Ag NW arrays have excellent SERS performance due to the many Ag NPs attached to the surface of the closely aligned Ag NWs, the limit of detection (LOD) for Basic Fuchsin (BF) and Crystal Violet (CV) detected by Ag NW arrays SERS substrates prepared with Ag electrodes are as low as 10−11and 10−14mol/L, respectively. This paper provides a reference for the preparation method of metal nanostructures, Ag NW arrays have good potential for application in the field of trace analysis.

Statistical properties of circular and rectangular multi-sinc Schell-model beams propagating in uniaxial crystals

With the extended Huygens–Fresnel principle, we derive the expressions for the spectral intensity, coherence, and effective beam width of circular and rectangular multi-sinc Schell-model (MSSM) beams propagating through uniaxial crystals. Numerical simulations are employed to extensively explore how beam and crystal parameters modulate the optical field. The results reveal that the propagating field exhibits multiple ring-shaped and array-like intensity distributions, with adjustable features such as the number of concentric rings, central brightness, array dimensions, and the morphology and diversity of sub-beams. Additionally, the spectral coherence displays an oscillatory distribution that evolves into a Gaussian distribution as the transmission distance increases. The anisotropy of uniaxial crystals not only influences the morphology of intensity distribution but also affects the evolution rate of coherence and the expansion rate of effective beam width. Our work contributes to optimizing beam propagation through uniaxial crystals, potentially benefiting precision optical systems in laser technology.

Evaluation of the effect of three dimensional antenna array design on early detection of cerebral hemorrhage with microwave imaging devices

Evaluation of the effect of three dimensional antenna array design on early detection of cerebral hemorrhage with microwave imaging devices

Cellular Nanointerface of Vertical Nanostructures: Impact of Size‐Modulated Nanopillar Arrays on Neuronal Morphology, Maturation, and Synapse Formation

Investigating the cellular mechanisms facilitated by highly ordered nanostructures in vitro neuronal networks is crucial for advancing biomedical research. However, the intricate effects of these nanostructures on cellular behavior remain unclear. Herein, we explore how variations in nanopillar (NP) array dimensions, defined by the spacing‐to‐diameter (S/D) ratio, influence cortical neuronal responses—including cellular morphology, mechanosensing, neuronal maturation, and synapse formation. NP arrays with a low S/D ratio accelerate neurite protrusion and enhance neuronal maturation. These topography‐driven changes are attributed to the degree of cell confinement on NPs, which can be visualized using focused ion beam scanning microscopy. Furthermore, the synaptic density in cortical neurons declines as the S/D ratio decreases, with neurons preferring to form synapses along the NPs. By utilizing correlative light and electron microscopy, the spatial organization of these synapses is mapped relative to the NP geometries, revealing specialized synaptic regions with remarkable clarity. This approach to designing high‐aspect‐ratio nanostructures with various S/D ratios holds broad applications in materials engineering, offering insights into nervous system engineering and neural‐interfacing bioelectronics.

Scalable imaging-free spatial genomics through computational reconstruction.

Tissue organization arises from the coordinated molecular programs of cells. Spatial genomics maps cells and their molecular programs within the spatial context of tissues. However, current methods measure spatial information through imaging or direct registration, which often require specialized equipment and are limited in scale. Here, we developed an imaging-free spatial transcriptomics method that uses molecular diffusion patterns to computationally reconstruct spatial data. To do so, we utilize a simple experimental protocol on two dimensional barcode arrays to establish an interaction network between barcodes via molecular diffusion. Sequencing these interactions generates a high dimensional matrix of interactions between different spatial barcodes. Then, we perform dimensionality reduction to regenerate a two-dimensional manifold, which represents the spatial locations of the barcode arrays. Surprisingly, we found that the UMAP algorithm, with minimal modifications can faithfully successfully reconstruct the arrays. We demonstrated that this method is compatible with capture array based spatial transcriptomics/genomics methods, Slide-seq and Slide-tags, with high fidelity. We systematically explore the fidelity of the reconstruction through comparisons with experimentally derived ground truth data, and demonstrate that reconstruction generates high quality spatial genomics data. We also scaled this technique to reconstruct high-resolution spatial information over areas up to 1.2 centimeters. This computational reconstruction method effectively converts spatial genomics measurements to molecular biology, enabling spatial transcriptomics with high accessibility, and scalability.

A nanophotonic approach to signal-to-noise ratio of quantum dot infrared photodetectors with surface plasmonic excitation

A nanophotonic approach to the signal-to-noise ratio (SNR) of an InAs-based quantum dot infrared photodetector (QDIP) with surface plasmonic excitation is reported. A 100 nm-thick Au film, perforated with a 3.1 μm-period, 2-dimensional square array of holes, referred to as a metal photonic crystal (MPC), is employed as a plasmonic coupler for it. Under the irradiance on the MPC integrated atop the QDIP, the fundamental surface plasma wave (SPW) is excited along their interface at ∼10.3 μm in wavelength. It carries the near-field that interacts with the quantum dots (QDs) under the interface. Depending on the presence of the coupler, the QDIP generates two different current–voltage (I-V) characteristics; one from the QDs normally working without MPC and the other from those coupled to the SPW near-field with it. The two I-V’s unfold the signal and noise current of each case with photoconductive gain. In their relation, generation-recombination and shot noises which are correlated with the detector signal current are directly affected by the plasmonic coupling but other sources including thermal noise are not relevant to it. Relying on these differences, the I-V analysis allows the SNR of each case and shows ∼20× enhancement by the plasmonic coupling. It reveals that most of the noise current is attributed to thermal fluctuations inherent to the quantum confinement of the QDIP. The SNR lower than the quantum efficiency in plasmonic enhancement is addressed.

Influence of silver nanoparticles on enhancing performance of optical absorption property in a perovskite solar cell

This report presents a mostly numerical investigation of solar absorptance enhancement in PSCs through solving partial differential equations. The designed structural device comprised five layers of the transparent conducting contact (ITO), the electron transport layer (TiO2), the active layer (CH3NH3PBI3) embedding with plasmonic silver nanoparticles (AgNPs), the hole transporting layer (NiO), and the back reflectors (Ag). The calculation results showed that the device performance was highly dependent on the particle size of AgNP, structural formation and the location of the AgNPs. Overall, the optimum particle radius was r=10nm, located at the middle of the activated layer z=0nm, a 2-dimensional array of 2×2 particles per unit cell and an interparticle distance of 4nm were achieved for the AgNPs in the active layer (AL) of the PSCs with the highest optical enhancement of η=1.24.

Modeling the hydrodynamic wake of an offshore solar array in OpenFOAM

Offshore solar is seen as a promising technology for renewable energy generation. It can be particularly valuable when co-located within offshore wind farms, as these forms of energy generation are complementary. However, the environmental impact of offshore solar is not fully understood yet, and obtaining a better understanding of the possible impact is essential before this technology is applied at a large scale. An important aspect which is still unclear is how offshore solar affects the local hydrodynamics in the marine environment. This article describes the hydrodynamic wake generated by an offshore solar array, arising from the interaction between the array and a tidal current. A computational fluid dynamic (CFD) modeling approach was used, which applies numerical large eddy simulations (LES) in OpenFOAM. The simulations are verified using the numerical model TUDFLOW3D. The study quantifies the wake dimensions and puts them in perspective with the array size, orientation, and tidal current magnitude. The investigation reveals that wake width depends on array size and array orientation. When the array is aligned with the current, wake width is relatively confined and does not depend on the array size. When the array is rotated, the wake width experiences exponential growth, becoming approximately 30% wider than the array width. Wake length is influenced by factors such as horizontal array dimensions and current magnitude. The gaps in between the floaters decrease this dependency. Similarly, the wake depth showed similar dependencies, except for the current magnitude, and only affected the upper meters of the water column. Beneath the array, flow shedding effects occur, affecting a larger part of the water column than the wake. Flow shedding depends on floater size, gaps, and orientation.

Fabrication of Hybrid Coated Microneedles with Donepezil Utilizing Digital Light Processing and Semisolid Extrusion Printing for the Management of Alzheimer's Disease.

Microneedle (MN) patches are gaining increasing attention as a cost-effective technology for delivering drugs directly into the skin. In the present study, two different 3D printing processes were utilized to produce coated MNs, namely, digital light processing (DLP) and semisolid extrusion (SSE). Donepezil (DN), a cholinesterase inhibitor administered for the treatment of Alzheimer's disease, was incorporated into the coating material. Physiochemical characterization of the coated MNs confirmed the successful incorporation of donepezil as well as the stability and suitability of the materials for transdermal delivery. Optical microscopy and SEM studies validated the uniform weight distribution and precise dimensions of the MN arrays, while mechanical testing ensured the MNs' robustness, ensuring efficient skin penetration. In vitro studies were conducted to evaluate the produced transdermal patches, indicating their potential use in clinical treatment. Permeation studies revealed a significant increase in DN permeation compared to plain coating material, affirming the effectiveness of the MNs in enhancing transdermal drug delivery. Confocal laser scanning microscopy (CLSM) elucidated the distribution of the API, within skin layers, demonstrating sustained drug release and transcellular transport pathways. Finally, cell studies were also conducted on NIH3T3 fibroblasts to evaluate the biocompatibility and safety of the printed objects for transdermal applications.

A Metamaterial Bandpass Filter with End-Fire Coaxial Coupling

A miniaturized metamaterial (MTM) bandpass filter (BPF) based on end-fire coaxial coupling is proposed. End-fire coaxial coupling is achieved by using the coaxial cavity to connect with the SubMiniature version A connector. The subwavelength characteristics of the MTM lead to the miniaturization advantages of the filter in transverse dimensions. Moreover, the longitudinal length of the coaxial cavity can be sharply reduced by introducing matched blocks. As a result, the proposed filter has miniaturization merit both in transverse and longitudinal dimensions. The full-wave simulation results further reveal that the MTM BPF exhibits the advantages of low loss, low reflection, and low group delay. Additionally, the fractional bandwidth is approximately 13% when |S11| is less than −15 dB. The MTM BPF might have potential applications to array antennas for easily being expanded to two dimensional arrays.

Improving light harvesting and charge carrier separation enabling enhanced photoelectrochemical hydrogen production by Sb2S3-decorated TiO2 nanotube arrays on porous Ti-photoanodes

The Ag + ions doped TiO2 nanotube arrays fabricated on Ti mesh through an electrochemical anodization process, and n/n heterostructure formed by coating the TiO2 nanotube array photoanode with an n-type stibnite (Sb2S3) layer improve photoelectrochemical water splitting reaction by enhancing light harvesting and charge carrier separation. Sb2S3 is chosen because of its suitable band gap position and strong visible light response. The Ag + ion incorporated TiO2 nanotube array coated with Sb2S3 exhibits a photocurrent density of 6.5 mA cm−2 vs. RHE, whereas bare TiO2 nanotube array coated with Sb2S3 and pristine TiO2 nanotube array exhibit photocurrent densities of 3.6 and 0.27 mA cm−2, respectively, under the same conditions, which is nearly 1.8 and 24 times greater than the TiO2 nanotube array coated with Sb2S3 and pristine TiO2 nanotube array photoanodes. The applied bias photon-to-current efficiency of Ag + ion incorporated TiO2 nanotube array coated with Sb2S3 is 3.6% and the improved Photoelectrochemical performance of Ag + ion doped TiO2 nanotube array coated with Sb2S3 is attributable to higher conductivity of TiO2 nanotube array caused by increased oxygen vacancies and broad optical activity of Sb2S3. The 1-dimensional TiO2 nanotube array device structure in the Ti mesh improves charge separation and light harvesting while reducing photogenerated charge carrier recombination and the potential of this novel device structure for advanced energy conversion applications is highlighted in this study.

Long-range molecular energy transfer mediated by strong coupling to plasmonic topological edge states

Abstract Strong coupling between light and molecular matter is currently attracting interest both in chemistry and physics, in the fast-growing field of molecular polaritonics. The large near-field enhancement of the electric field of plasmonic surfaces and their high tunability make arrays of metallic nanoparticles an interesting platform to achieve and control strong coupling. Two dimensional plasmonic arrays with several nanoparticles per unit cell and crystalline symmetries can host topological edge and corner states. Here we explore the coupling of molecular materials to these edge states using a coupled-dipole framework including long-range interactions. We study both the weak and strong coupling regimes and demonstrate that coupling to topological edge states can be employed to enhance highly-directional long-range energy transfer between molecules.

Experimental performance of a two-receivers and two-transmitters array X-ray communication system

In this work, we constructed a two-transmitter, two-receiver array based on grid-controlled modulated X-ray tubes and plastic-scintillator-coupled SiPM detectors to improve the communication rate of X-ray communication (XCOM) systems. The effects of various working parameters, and array dimensions on the bit-error-rate of the system were investigated. We derived the relationship between array dimensions and spatial correlation coefficient theoretically, and pointed out that a higher spatial correlation coefficient is the main reason affecting system performance experimentally. The array communication system achieves a communication data rate of 3.6 Mbps under a 12.5 cm laboratory atmospheric channel with a moderate spatial correlation coefficient of 0.5. The array XCOM system can effectively increase the data rate compared with previous work. This study can provide an experimental foundation and design reference for the establishment of a multiple-input, multiple-output array XCOM system.

Quality and Quantity Control of Mitochondria Injection Into Single Cells With Robot-Aided Micro-Manipulation System

Mitochondrial dysfunction plays a significant role in the development of fatal diseases such as aging, cancer, and Alzheimer’s. Transferring mitochondria to cells is a new and potential treatment for mitochondrial DNA (mtDNA)-related illnesses. This article describes a novel technique to control the quality and quantity of mitochondria injected into single live cells using a robot-aided microneedle and optical tweezers (OTs)-based micromanipulation system. Isolated mitochondria and cells are patterned in a 1-dimensional (1-D) array in a microfluidic device, and a robot-aided microneedle collects the predefined number of functional mitochondria with the help of OTs. Then, the microneedle precisely and non-invasively injects these collected mitochondria into single live cells. Given that the two manipulation tools of OTs and microneedle were used, a switch controller strategy is developed to enable mitochondria trapping and injection with OTs and microneedle-based micromanipulator, respectively. The effectiveness of the developed robotic system is experimentally demonstrated with automated injections of isolated mitochondria into HeLa and mesenchymal stem cells (aMSCs). A precise and efficient quality and quantity control of mitochondria injection was possible by using Ots in conjunction with microneedle and microfluidics technologies. Quality-and quantity-controlled ability is analyzed and compared with the traditional mitochondria transfer method (co-culture). Biological tests are further conducted to assess the viability of mitochondria recipient cells. Experimental results demonstrate that the developed system can non-invasively transfer healthy mitochondria into single live cells while precisely controlling the quantity and quality of injected mitochondria. The proposed mitochondrial transfer method has the potential to advance precision medicine methods, particularly for cellular therapy of (mtDNA)-related diseases. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This study was motivated by the problem of inefficient methods of mitochondria injection into single, small, living cells. Due to the issue of microneedle clogging, existing mitochondria injection methods can only inject mitochondria into cells with a 0.3 to 2% efficiency. To address this issue, we have developed an automated method of mitochondria injection into cells that can inject mitochondria into single cells non-invasively with an efficiency of up to 80 %. Existing methods of mitochondria injection also ignored the heterogeneity of mitochondria, such as functionality and the precise number of mitochondria prior to injection. Our methodology can efficiently and precisely control the quality and quantity of mitochondria injection into single cells, which can be useful for the discovery of new information concerning precision medicine, particularly in diseases associated with mtDNA.

Kirigami enabled reconfigurable three-dimensional evaporator arrays for dynamic solar tracking and high efficiency desalination.

A kirigami-engineered composite hydrogel membrane is exploited for the construction of three dimensional (3D) solar-tracking evaporator arrays with outstanding evaporation performance and salt tolerance. The hybrid nanofiber network in the hydrogel membrane offers favorable water transport dynamics combined with excellent structural robustness, which are beneficial for the engineering of 3D dynamic structures. Periodic triangular cuts patterned into the membrane allow formation and reconfiguration of 3D conical arrays controlled by uniaxial stretching. With these structures, the tilt angles of the membrane surface are actively tuned to follow the solar trajectory, leading to a solar evaporation rate ~80% higher than that of static planar devices. Furthermore, the tapered 3D flaps and their micro-structured surfaces are capable of localized salt crystallization for prolonged solar desalination, enabling a stable evaporation rate of 3.4 kg m-2 hour-1 even in saturated brine. This versatile design may facilitate the implementation of solar evaporators for desalination and provide inspirations for other soft functional devices with dynamic 3D configurations.

Optimizing Method for Photovoltaic Water-Pumping Systems under Partial Shading and Changing Pump Head

Photovoltaic systems for pumping water, based on direct current powered motor pumps, have great application in small rural regions without electrical networks. In addition, these systems provide environmental benefits by replacing fossil fuels. However, these systems reduce their performance due to partial shading, which is magnified by the internal mismatch of the PV modules. This work proposes an intelligent, low-cost, and automatic method to mitigate these effects through the electrical reconfiguration of the PV array. Unlike other reported techniques, this method considers the pump head variations. For that, the global voltage and current supplied by the PV array to the motor pump subsystem are introduced to an artificial neural network and to a third-order equation, which locates the shaded PV module and detects the pump head, respectively. A connection control implements the optimal electrical rearrangement. The selection is based on the identified partial shading pattern and pump head. Finally, the switching matrix modifies the electrical connections between the PV modules on the PV array without changing the interconnection scheme, PV array dimension, or physical location of the PVMs. The proposed approach was implemented in a real PV water pumping system. Low-cost and commercial electronic devices were used. The experimental results show that the output power of the PV array increased by 8.43%, which maintains a more stable level of water extraction and, therefore, a constant flow level.