Array Structure Research Articles

Structure and dynamics of cholesterol-mediated aquaporin-0 arrays and implications for lipid rafts.

Aquaporin-0 (AQP0) tetramers form square arrays in lens membranes through a yet unknown mechanism, but lens membranes are enriched in sphingomyelin and cholesterol. Here, we determined electron crystallographic structures of AQP0 in sphingomyelin/cholesterol membranes and performed molecular dynamics (MD) simulations to establish that the observed cholesterol positions represent those seen around an isolated AQP0 tetramer and that the AQP0 tetramer largely defines the location and orientation of most of its associated cholesterol molecules. At a high concentration, cholesterol increases the hydrophobic thickness of the annular lipid shell around AQP0 tetramers, which may thus cluster to mitigate the resulting hydrophobic mismatch. Moreover, neighboring AQP0 tetramers sandwich a cholesterol deep in the center of the membrane. MD simulations show that the association of two AQP0 tetramers is necessary to maintain the deep cholesterol in its position and that the deep cholesterol increases the force required to laterally detach two AQP0 tetramers, not only due to protein-protein contacts but also due to increased lipid-protein complementarity. Since each tetramer interacts with four such 'glue' cholesterols, avidity effects may stabilize larger arrays. The principles proposed to drive AQP0 array formation could also underlie protein clustering in lipid rafts.

Feasibility study on the micro-forming of novel metal foil arrays based on submerged cavitating water-jet impingement

With the increasing demand for metal foil parts with micro-array structures in micro-electromechanical systems (MEMS), it is urgent to explore a novel array micro-forming technology with high efficiency, low cost, and high flexibility. The cavitation water jet uses the high-energy shock wave generated by the collapse of the cavitation bubble group as the loading force. It has the characteristics of large range of action, uniform pressure distribution, and can realize large-area array micro-forming processing. To verify the feasibility of cavitating water jet array micro-forming, this paper performs cavitating water jet array micro-forming on 304 stainless steel foil with a thickness of 80 μm, and analyzes the variation of cavitation bubbles collapse impact zone with target distance. The effects of target distance and impact time on the forming quality of metal foil array micro-holes were studied from the aspects of forming depth, surface roughness, and thickness thinning rate. The results show that the forming depth and uniformity of the array micro-holes located in the cavitation collapse area increase with time. However, with the increase of target distance, the forming depth increases first and then decreases. When the target distance is L = 120 mm, the forming depth reaches the maximum. The surface roughness ( Ra) of the array micro hole is Ra = 1.54 μm. The thickness thinning rate of the micro-forming parts is between 2% and 10%, and the maximum thickness thinning rate in the die fillet area is 13.5%. This paper provides a novel processing method for manufacturing metal foil parts with micro array structure.

Preparation of nickel-manganese based bimetallic hydroxide nanosheets for enhanced electrocatalytic oxygen evolution reaction

Abstract This paper uses a common one-step hydrothermal method to prepare NiMn-LDH/NF (Layered Double Hydroxide, LDH) oxygen evolution catalyst with outstanding performance. The NiMn-LDH grows into a nanosheet array structure on nickel foam (NF) and it has a big surface area and exceptional ion transport function that could accelerate the diffusion rate of electrocatalytic products. It attempted to modulate the molar proportion of Ni and Mn to explore the oxygen evolution reaction (OER) performance of the NiMn-LDH/NF catalysts. It was found that when Ni:Mn=4:1 (molar ratio, hereinafter), the nanosheets grew more densely and had better OER performance and stability. The electrochemical test results show that the Ni4Mn-LDH/NF catalyst exhibits an overvoltage of 341 mV at a current density of 10 mA cm−2, and the Tafel slope is only 98.99 mV dec−1.

A flexible strategy to fabricate trumpet-shaped porous PDMS membranes for organ-on-chip application.

Porous polydimethylsiloxane (PDMS) membrane is a crucial element in organs-on-chips fabrication, supplying a unique substrate that can be used for the generation of tissue-tissue interfaces, separate co-culture, biomimetic stretch application, etc. However, the existing methods of through-hole PDMS membrane production are largely limited by labor-consuming processes and/or expensive equipment. Here, we propose an accessible and low-cost strategy to fabricate through-hole PDMS membranes with good controllability, which is performed via combining wet-etching and spin-coating processes. The porous membrane is obtained by spin-coating OS-20 diluted PDMS on an etched glass template with a columnar array structure. The pore size and thickness of the PDMS membrane can be adjusted flexibly via optimizing the template structure and spinning speed. In particular, compared to the traditional vertical through-hole structure of porous membranes, the membranes prepared by this method feature a trumpet-shaped structure, which allows for the generation of some unique bionic structures on organs-on-chips. When the trumpet-shape faces upward, the endothelium spreads at the bottom of the porous membrane, and intestinal cells form a villous structure, achieving the same effect as traditional methods. Conversely, when the trumpet-shape faces downward, intestinal cells spontaneously form a crypt-like structure, which is challenging to achieve with other methods. The proposed approach is simple, flexible with good reproducibility, and low-cost, which provides a new way to facilitate the building of multifunctional organ-on-chip systems and accelerate their translational applications.

Regulating Li+ transport behavior by cross-scale synergistic rectification strategy for dendrite-free and high area capacity polymeric all-solid-state lithium batteries

The inability to effectively inhibit the lithium (Li) dendrite growth is identified as the real culprit hindering the practical application of polyethylene oxide (PEO)-based electrolytes. Herein, a novel PEO composite electrolyte with ion rectifier is developed based on the cross-scale synergistic rectification strategy. At the micro-scale, the array structure of the ion rectifier suppresses the growth of PEO crystals and their distribution in the non-ionic conduction direction through space confinement, alleviating ion-migration crosstalk and enabling polymer chain rectification. Furthermore, the matrix contains abundant copper ions and oxygen-containing groups that inhibit anion conduction and accelerate Li+ migration at the nanoscale, respectively, to achieve ion flow rectification. Implementing this strategy results in a uniform, fast, and stable Li+ migration/diffusion behavior from the electrolyte to anode interface. The critical current density of the PEO electrolyte is increased to 2.5 mA cm−2, indicating a significant improvement in dendrite growth inhibition. Impressively, the composite electrolytes exhibit long-term stability (>4000 h at 0.2 mA cm−2) and ultra-high current-density tolerance (>200 h at 1 mA cm−2). Moreover, the composite electrolytes enable stable cycling of high-area-capacity (3.11 mAh cm−2, 20 mg cm−2) LiFePO4/Li pouch cells, highlighting the importance of this strategy for the practical application of PEO electrolytes.

A Miniature PMUT Array for Medical Applications

Abstract Wearable continuous monitoring technology and internal and cerebrovascular imaging are the frontier hot area of current scientific research, which are of great significance to improving human life and health. Ultrasonic imaging can obtain information such as deep tissue structure by transmitting ultrasonic waves into the tissue and detecting echo signals, and ultrasonic imaging technology has the advantages of high imaging depth, high resolution, high safety, fast and convenient, etc. It is one of the important technologies in the medical field such as wearable continuous monitoring technology and internal cardiovascular and cerebrovascular imaging. But miniaturization and low power consumption are necessary conditions for the success of such medical applications. Therefore, the ultrasonic imaging technology using a miniature ultrasonic probe is one of the most promising imaging technologies for this type of medical application. Aiming at the common technical problems of traditional ultrasonic transducers such as large volume, narrow bandwidth, high power consumption, difficulty in preparing two-dimensional arrays, and difficulty in integrating with ICs. In this paper, the electromechanical-acoustic multi-field coupling mechanism and array structure design technology of MEMS high-performance PMUT ultrasonic transducer elements are first studied, and a CMOS-compatible miniature PMUT high-performance array ultrasonic device suitable for this type of medical application is developed. The simulation results of the transducer are given. The measurement of various physical parameters of the transducer sample and the results of its application in the ultrasonic imaging system show that the miniature PMUT linear array ultrasonic sensor we designed is a kind of high performance ultrasonic array sensors that can be widely used in wearable continuous monitoring technology and internal cardiovascular and cerebrovascular imaging.

Equilibrium and self-assembly of Janus particles at liquid-liquid interfaces for the film formation

This article investigates the equilibrium arrangement, self-assembly process, and subsequent curing of amphiphilic snowman-shaped Janus particles at the oil-water interface. The independent Janus particles are in vertical equilibrium state and the contact position of the oil-water interface is at the largest cross section of the particle’s hydrophobic phase. Under the effect of the surface tension and the adsorption of materials, Janus particles may form particle combinations including the particle pairs and the particle triangle, whose inner and outer sides have the liquid surface exhibiting completely opposite contact angles. Particle combinations form stable parallel double-chain structures with diverse shapes after the self-assembly process. However, the single Janus particles attain a state of mechanical equilibrium under the influence of surrounding particles, enabling them to assemble into regular array structures. The relationship of interfacial tension coefficient between phases can be changed by adjusting the oil-water system, which leads to variations in the self-assembly speed and the final arrangement results. The thin-film with uniformly distributed vertical particles is achieved by replacing the underlying deionized water with a curing agent. Based on the understanding of the interactions between irregularly shaped Janus particles at the oil-water interface, it will be convenient to achieve the controllable self-assembly and widely applications of these particles.

Innovative solar PV array design: mitigating partial shading for Optimal Performance Index

Photovoltaic arrays are popular for green energy but suffer productivity loss from module faults and partial shading conditions (PSC). These two faults must be distinguished to avoid a permanent shutdown. Hence, this article presents two Novel 4 X 4 array structures with fewer tie-lines to address mismatch power loss under these abnormal conditions. The performances of these novel arrays are compared with Total-Cross-Tied (TCT), Honey-Comb (HC), and Bridge-Link (BL) under three PSC categories, with six cases falling into each category. PSCs are analysed at constant and varying temperatures, along with row and column module faults. Thirteen performance indices, including the Overall Performance Index (OPI), are addressed. The percentage reduction of tie-lines in novel topologies, along with their strengths and limitations, and variation of the performance indices of all the topologies are analysed. The obtained results reveal that the Novel-1 and Novel-2 arrays capture the global maximum power point (GMPP) in 67% and 78% of the analysed situations, respectively, outperforming standard arrangements and decreasing tie-lines. These findings support the efficacy and economic benefits of the novel array configurations, which provide considerable increases in PV system performance and reliability across a variety of environmental circumstances.

Biomimetic multi-functional 3D fog collector: Independent of fog flow direction

The shortage of freshwater resources has a great impact on the daily life of human beings, and fog collection has become an effective mitigation measure. In this paper, inspired by the nanofabricated desert beetle, honeycomb, Euphorbia antiquorum L. and cactus, a 3D fog collector combining a conical array structural gradient and a wettability gradient was presented, with special three-dimensional array structure (TA-L/B (PPC)) that ensures that the fog-collecting efficiency of the samples is virtually independent of the direction of the fog flow. The fog collection efficiency of sample TA-L/B (PPC) is close to 4.3 g·h−1·cm−2, a value that is 1.77 times higher than the surface fog collection efficiency of the copper sheet (OS) sample. By rationally designing the surface structure of the sample, the fog circulation process is accelerated, and a sustainable and stable fog collection process is achieved.

A Deep Learning Application for Dolph-Tschebyscheff Antenna Array Optimisation

This paper proposes a design for a Dolph-Tschebyscheff-weighted microstrip antenna array using a deep learning application. For this purpose, a multilayer perceptron and a deep learning model, both created using the same data set generated by a genetic algorithm, were compared. The antenna array population is initially generated randomly and then optimised with a genetic algorithm. The data produced by this model becomes a data set used for training in the deep learning application. The dimensions and specifications of the antenna array are obtained from this application, ensuring precision and optimisation in the design process. A new microstrip antenna array structure is employed for the proposed method, taking advantage of this design technique. The Dolph-Tschebyscheff weights are applied to achieve better characteristics for the microstrip antenna array, thus obtaining low side lobe levels, which are crucial for enhancing signal clarity and reducing interference. The results demonstrate that the proposed algorithm significantly improves the specifications of the structure. This improvement highlights the potential for integrating deep learning with traditional optimisation algorithms for advanced antenna design.

Coupling and characterization of a Si/SiGe triple quantum dot array with a microwave resonator

Abstract Scaling up spin qubits in silicon-based quantum dots is one of the pivotal challenges in achieving large-scale semiconductor quantum computation. To satisfy the connectivity requirements and reduce the lithographic complexity, utilizing the qubit array structure and the circuit quantum electrodynamics (cQED) architecture together is expected to be a feasible scaling scheme. A triple-quantum dot (TQD) coupled with a superconducting resonator is regarded as a basic cell to demonstrate this extension scheme. In this article, we investigate a system consisting of a silicon TQD and a high-impedance TiN coplanar waveguide (CPW) resonator. The TQD can couple to the resonator via the right double-quantum dot (RDQD), which reaches the strong coupling regime with a charge–photon coupling strength of g 0/(2π) = 175 MHz. Moreover, we illustrate the high tunability of the TQD through the characterization of stability diagrams, quadruple points (QPs), and the quantum cellular automata (QCA) process. Our results contribute to fostering the exploration of silicon-based qubit integration.

Effect of Multilayer Structure and Column Array Structure on Mechanical Properties and Fracture Behavior of Heterogeneous Steel

Effect of Multilayer Structure and Column Array Structure on Mechanical Properties and Fracture Behavior of Heterogeneous Steel

Fabrication of RuO2-graphene/graphene thick-and-dense micro-hole array material by femtosecond laser for high volumetric rate performance

Nanostructured materials have a great application prospect in the next generation of electrochemical energy storage devices. However, there is a great obstacle for thick and dense electrodes with large tortuosity to simultaneously attain high areal and rate performance at the same time to meet the practical requirements. Herein, a simple electrostatic self-assembly method is adopted to anchor RuO2 onto graphene nanoflakes, the thick and dense film of RuO2-Graphene/Graphene(RuO2-G G-1) are prepared by filtration and mechanical compression, and then the micro-hole array structure was fabricated by femtosecond laser drilling, which shortened the diffusion path of hydrogen ion (H+). After etching, the pore diameter is 7 μm; the pore spacing is 40 μm and the array was regular. The mass loss of the electrode caused by etching was only 3 %, and the relative density of the electrode reached 79 %. Under the same thickness of the electrode, the pore electrode obviously reduces the ion resistance. The micro-hole array not only improves the areal and volumetric capacity of the RuO2-G G-1 electrode, but also improves the rate performance of the electrode., the rate capability increased from 65.6 % to 87.7 % at 20 A g-1. The study provides a powerful technique for the fabrication of dense and thick electrode in energy storage system.

Numerical investigation on heat transfer and pressure drop characteristics of Micro-Pillar array surface

The array surface structure can improve heat transfer efficiency and achieve large heat transfer area per unit of volume. In this study, a numerical simulation using CFD method was carried out to construct a dual-channel three-dimensional mathematical model with micro-pillar array surface. The characteristic of heat transfer and flow resistance for the arrayed surface structure have been studied. In addition, four different array configurations, including cylindrical, elliptical, quadrangular and herringbone, were considered to compare the thermal performance and flow behavior. The configuration with the best overall performance was obtained as cylindrical by comparison. The effects of different heights, arrangement methods and pitches on the system performance were analyzed. The velocity distribution on the array surface was also obtained. It is found that the cylindrical array structure has obvious advantages in overall performance, with more uniform surface velocity distribution and better overall performance at lower Re conditions.

Formation mechanism of the U-shaped spectrum based on a simple plasma–dielectric–plasma (PDP) waveguide

Manipulating electromagnetic (EM) waves by plasma–dielectric–plasma (PDP) waveguides or plasma array structures presents significant potential in microwave signal processing, such as filtering, signal delay, and EM enhancement or shielding. Owing to the simple structure and easy fabrication, the waveguide with a tooth-shaped resonator has been a strong candidate as a filtering device. Based on our previous work focusing on U-shaped filtering excited by PDP waveguides with a double-teeth structure, in this work, the formation mechanism of a U-shape filtering spectrum is systematically explored by transmission line theory (TLT) with proper field distributions. The results indicate that the U-shape spectrum consists of boundary edges and a filtering stopband. The boundary edges are attributed to Fano-type resonance, and the enhanced destructive interference from double teeth is responsible for the stopband. Such an approach shows a specific and clear mechanism for the generated U-shaped spectrum. In addition, the theoretical analysis of double teeth without Fano-type resonances is rigorously demonstrated using TLT, which significantly contributes to bandwidth modulation of stopband filtering in theory. These results contribute to the understanding of the formation mechanism of a U-shaped spectrum from a gap plasmon waveguide (such as PDP or metal–insulator–metal (MIM)) with tooth-shaped resonators, offering a feasible direction for the optimization of filtering properties, as well as offering significant parameters for subsequent experimental design.

Enhancing efficiency in spaceborne phased array systems: MVDR algorithm and FPGA integration

Digital Beamforming (DBF) has garnered significant attention within the space community, driven by the heightened flexibility offered by satellites equipped with active antennas for diverse applications like spaceborne synthetic aperture radar (SAR) systems and communication services. This paper presents a comprehensive exploration encompassing analysis, design, and implementation of a Minimum Variance Distortionless Response (MVDR) algorithm tailored for application in a Digital Beamforming Receiver system. The described system leverages the capabilities of the high-speed Analog to Digital Converter (ADC) device EV12AQ600, space-qualified, and the high-performance FPGA XCKU085. These components are seamlessly integrated into the EV12AQ60X-ADX-EVM evaluation board, thoughtfully provided by Teledyne e2v Semiconductors. The design methodology outlined herein is driven by the overarching objective to minimize FPGA resource utilization and power consumption for spaceborne phased array systems. This objective is chiefly met through the implementation of a systolic array structure adept at processing both real and complex input samples. This innovative approach results in a substantial reduction in allocated resources compared to conventional architectures. Furthermore, the design incorporates the use of the CORDIC algorithm to compute the inverse of the correlation matrix, obviating the need for square root and division operations. This strategic utilization of algorithms enhances the system's efficiency in terms of resource utilization, computational load, and processing time. To validate the anticipated behavior of the adaptive beamforming system, various radio frequency (RF) input signals are applied to the system, which is physically instantiated on the EV12AQ60X-ADX-EVM evaluation board. The experimental results affirm the efficacy of the proposed design, underscoring its suitability for spaceborne applications.

Research on the influence of different pyramid array structures on plane blackbody emissivity

The plane blackbody radiation source is pivotal to the infrared remote sensing detection system, with emissivity serving as a critical metric for its performance evaluation. This metric is predominantly influenced by the surface structure and coating properties. To improve emissivity, existing works have utilized pyramid structures to expand the contact area between the radiation surface and light, thereby augmenting light absorption. Nonetheless, there is relatively little research exploring the impact of pyramid structure on emissivity, leading to a scarcity of related emissivity data for plane blackbody. In this paper, we explored the impact on the blackbody emissivity induced by different pyramid structures, including the triangular pyramid array (TPA), the quadrangular pyramid array (QPA), the pentagonal pyramid array (PPA), and the hexagonal pyramid array (HPA). Also, the effects involving coating properties, the base-height ratio of the pyramid, and reflection characteristics on emissivity were investigated based on the Monte Carlo Method. Then, the specimens with diffuse reflection (DR) and near-specular reflection (NSR) were fabricated and tested experimentally. The uncertainties of simulation and experiment were maintained below 0.21 % and 0.50 %, respectively. Experimental results are well aligned with the corresponding simulation results, indicating that the normal emissivity of the TPA blackbody is 0.12 % higher than the QPA blackbody, and the directional emissivity uniform of the TPA blackbody is superior to that of the QPA blackbody for the DR model in the 8–14 μm waveband. Furthermore, the temperature field distributions of radiation surface for TPA and QPA blackbody were analysed, noting a maximum temperature difference of 50 mK and 30 mK, respectively. This paper provides experimental support and design references for further improving the emissivity of plane blackbodies.

3D-printed multifunctional biomass hydrogel device for controlled photothermal distribution and molecular release

Photothermal therapy based on photothermal conversion has received increasing attention due to its non-invasiveness and low side effects. In this study, a 3D-printed biomass photothermal therapy device was prepared for accurate control of photothermal conversion and molecular release. The prepared black phosphorus nanosheets (BPNSs) showed excellent photothermal performance and antibacterial activity. A temperature-regulated sol-gel reversible system was prepared with konjac glucomannan (KGM), tara gum (TG), BPNSs, and manganese dioxide (MnO2) nanoparticles. The sol-gel transition was attributed to the change of interactions of hydrogen bond, and molecular entanglement. Photothermal conversion films with accurate multi-layer and array structures were prepared by 3D printing using the biomass sol-gel conversion system. The photothermal conversion efficiency was regulated by the concentration of BPNSs and MnO2. Under infrared radiation (808 nm, 1 W/cm2) for 5 min, the temperatures of hydrogel films with a MnO2 concentration of 0, 0.5, and 1 % were raised from 25 to 29.3, 61.8, and 90.8 °C, respectively. The accurate temperature distribution induced the controlled release of small active molecules such as epigallocatechin gallate (EGCG) loaded in hydrogels, which was resulted from the changes in the hydrogel structure and the decrease in adsorption energy between polysaccharide and EGCG at high temperatures. This study provides a biomass 3D-printed multifunctional photothermal therapy device and more understanding of the molecular release during photothermal conversion.

Simultaneous Detection of Multiple Respiratory Pathogens Using an Integrated Microfluidic Chip.

Respiratory pathogens pose significant challenges to public health, demanding efficient diagnostic methods. This study presents an integrated microfluidic chip for the simultaneous detection of multiple respiratory pathogens. The chip integrates magnetic bead-based nucleic acid extraction and purification, acoustic streaming-driven mixing, liquid equalization, and multiplex PCR amplification with in situ fluorescence detection. Nucleic acid extraction takes only 12 min, yielding results comparable to commercial kits. Efficient mixing of magnetic beads is achieved through a combination of designed micropillars and bubble-trapping array structures. The micropillars maintain the aqueous phase in the mixing chamber, while the bubble-trapping arrays enable stable formation of bubbles, serving as a micromixer under the acoustic field. To prevent cross-contamination, an oil-encapsulated water droplet system is incorporated throughout nucleic acid extraction and PCR amplification. This assay displays remarkable multiplex analysis capability on a single chip, enabling the simultaneous detection of 12 common respiratory pathogens with a low detection limit of 10 copies/μL. Moreover, this method demonstrates excellent practical applicability in clinical nasal samples. Compared to many microfluidic chip-based molecular biology methods, the assay exhibits comparable or superior multipathogen analysis capability, sensitivity, and speed, completing the sample-to-answer process in approximately 70 min. This integrated microfluidic device offers a promising multiplex molecular diagnosis platform for on-site simultaneous detection of multiple pathogens.

Vertical Conductive Metal-Organic Framework Single-Crystalline Nanowire Arrays for Efficient Electrocatalytic Hydrogen Evolution.

The construction of crystalline metal-organic frameworks with regular architectures supportive of enhanced mass transport and bubble diffusion is imperative for electrocatalytic applications; however, this poses a formidable challenge. Here, a method is presented that confines the growth of nano-architectures to the liquid-liquid interface. Using this method, vertically oriented single crystalline nanowire arrays of an Ag-benzenehexathiol (BHT) conductive metal-organic framework (MOF) are fabricated via an "in-plane self-limiting and out-of-plane epitaxial growth" mechanism. This material has excellent electrocatalytic features, including highly exposed active sites, intrinsically high electrical conductivity, and superhydrophilic and superaerophobic properties. Leveraging these advantages, the carefully designed material demonstrates superior electrocatalytic hydrogen evolution activity, resulting in a low Tafel slope of 66mVdec-1 and a low overpotential of 275mV at a high current density of 1Acm-2. Finite element analysis (FEA) and in situ microscopic verification indicates that the nanowire array structure significantly enhances the electrolyte transport kinetics and promotes the rapid release of gas bubbles. The findings highlight the potential of using MOF-based ordered nanoarray structures for advanced electrocatalytic applications.