Small Cell Size Research Articles

Left-handed metamaterial based on circular split ring (CSRR) resonator for microwave sensing Application

This paper presents a new metamaterial structure specifically designed to operate in the L, S, and C frequency bands. It is characterized by a small unit cell size of 15mm × 15 mm. The metamaterial's electromagnetic properties are thoroughly examined, utilizing FR-4 substrate material and copper circular split ring resonators (CSRRs). The Computer Simulation Technology (CST) software uses the finite integration technique (FIT) to precisely model the effective parameters over a frequency range of 0–6 GHz. In simulations and experiments, the structure demonstrates negative refractive index, effective permittivity, and effective permeability. The electric and magnetic field distributions within the unit cell are accurately characterized using vector fields. In addition, the equivalent circuit is simulated and depicted using ADS software, with comparisons drawn between the measured data and the simulated data. The experimental validation, conducted using six varying thicknesses of FR4 materials, verifies the resemblance between the simulated and the measured transmission coefficients. Moreover, the effective medium ratio (EMR) of the metamaterial is calculated to be 12.74, indicating its promising capabilities for microwave sensing applications. The examination of the sensor model uncovers such metrics as quality factors, frequency detection resolution (FDR) values, and sensitivities, all of which enhance our comprehension of the material's performance. This discovery has the potential to advance the development of sensing metamaterials, which could significantly impact various applications and enhance research in the field.

Translational control of MPS1 links protein synthesis with the initiation of cell division and spindle pole body duplication in Saccharomyces cerevisiae.

Protein synthesis underpins cell growth and controls when cells commit to a new round of cell division at a point in late G1 of the cell cycle called Start. Passage through Start also coincides with the duplication of the microtubule-organizing centers, the yeast spindle pole bodies, which will form the 2 poles of the mitotic spindle that segregates the chromosomes in mitosis. The conserved Mps1p kinase governs the duplication of the spindle pole body (SPB) in Saccharomyces cerevisiae. Here, we show that the MPS1 transcript has a short upstream open reading frame (uORF) that represses the synthesis of Mps1p. Mutating the MPS1 uORF makes the cells smaller, accelerates the appearance of Mps1p in late G1, and promotes completion of Start. Monitoring the SPB in the cell cycle using structured illumination microscopy revealed that mutating the MPS1 uORF enabled cells to duplicate their SPB earlier at a smaller cell size. The accelerated Start of MPS1 uORF mutants depends on the G1 cyclin Cln3p and the transcriptional repressor Whi5p but not on the Cln1,2p G1 cyclins. These results identify growth inputs in mechanisms that control duplication of the microtubule-organizing center and implicate these processes in the coupling of cell growth with division.

Micro-layered film and foam alternating structures: A novel passive daytime radiative cooling material

This study investigates the confined foaming mechanisms and passive cooling performance of Micro-/Nano-Layered (MNL) film/foam alternating structures. These structures consist of solid poly(carbonate) (PC) film layers and foamed poly(methyl methacrylate) (PMMA) layers. We examine the impact of confinement effects, layer thicknesses, and foaming conditions on cell morphology, cell nucleation, growth, and bulk expansion behavior. Samples ranging from 1 to 513 layers were foamed at 20 MPa and temperatures between 70 and 150°C. We identified three distinct cell structures—multiple, double, or single row(s) of cells—in MNL film/foam structures. We observed that cell size decreases and cell nucleation density increases with increasing layer count. The highest cell nucleation density (1.1×1013 cells/cm3) and smallest cell size (400 nm) were achieved in a 513-layer sample foamed at 70°C and 20 MPa. MNL samples primarily expand vertically, with the apparent expansion ratio ranging from 2.3 to 11 times as layers increase. Samples with double or single row(s) of cells exhibited tensile strengths (∼30 MPa) comparable to their solid counterparts and thermal conductivities (29.7 mW/m·K) comparable to air. Our samples exhibited high solar radiation reflection (93.5 %) and strong infrared emissivity (91.2 %) in the atmospheric transparent window. Mid-day passive cooling experiments showed an average temperature of 17.7°C lower under our sample than ambient conditions. Given these combined properties and the cost-effective nature of the manufacturing method, our samples are readily applicable for building applications, offering significant energy savings and contributing to the mitigation of global warming.

Choice of medium affects PBMC quantification, cell size, and downstream respiratory analysis

High-resolution respirometry (HRR) can assess peripheral blood mononuclear cell (PBMC) bioenergetics, but no standardized medium for PBMC preparation and HRR analysis exist. Here, we study the effect of four different media (MiR05, PBS, RPMI, Plasmax) on the count, size, and HRR (Oxygraph-O2k) of intact PBMCs. Remarkably, the cell count was 21 % higher when PBMCs were resuspended in MiR05 than in PBS or Plasmax, causing O2 flux underestimation during HRR due to inherent adjustments. Moreover, smaller cell size and cell aggregation was observed in MiR05. Based on our findings, we propose that Plasmax, PBS or RPMI is more suitable than MiR05 for HRR of intact PBMCs. We provide oxygen solubility factors for Plasmax and PBS and encourage further optimization of a standardized HRR protocol for intact PBMCs.

Studies on a hadronic calorimeter with MPGD technology for a future Muon Collider experiment

In the context of the European strategy for particle physics, the Multi-TeV Muon Collider has emerged as a compelling alternative for advancing our understanding of the Standard Model, after the full exploitation of the High-Luminosity LHC. The physics programme at the Muon Collider includes precise measurements in the Higgs boson sector and the search for new physics at the TeV scale. Achieving these goals relies on accurate full event reconstruction, including the identification and precise four-momentum estimation of various particles. The Particle Flow (PF) algorithm is one of the most suitable approach for this task, exploiting information from tracking, calorimeter, and muon detectors for particle identification and measurements of their momenta/energies. Tracking detectors measure charged particle momenta, while calorimeters provide energy measurements for photons and neutral hadrons. Therefore, a combination of an exceptional tracking system and high-granularity calorimeters is necessary. However, one of the biggest challenges for a future experiment at the Muon Collider is to discriminate the product of the μμ collisions from the intense beam-induced-background (BIB), due to the unstable nature of muons, whose decay products interact with the detector material. To address this, an innovative hadronic calorimeter (HCAL) based on Micro Pattern Gas Detectors (MPGDs) is proposed. MPGDs offer robust technology for high radiation environments and a high granularity for precise spatial measurements. Dedicated studies are needed to assess and optimize the performance of an MPGD-based HCAL, including the development of medium-scale prototypes for performance measurements. The response of HCAL to incoming particles is examined through Monte Carlo simulations using Geant4, comparing the performance of digital and semi-digital readouts, with energy resolution as the figure of merit. The simulated geometry will be integrated into the Muon Collider software to study its impact on jet reconstruction within the full apparatus and in the presence of BIB. The simulation will be also validated through the test of a small-size calorimeter cell equipped with advanced resistive MPGD technologies, namely resistive MicroMegas, resistive μRWELL and RP-WELL.

Light-dependent chloroplast relocation in wild strawberry (Fragaria vesca)

ABSTRACT Chloroplast photorelocation is a vital organellar response that optimizes photosynthesis in plants amid fluctuating environmental conditions. Chloroplasts exhibit an accumulation response, in which they move toward weak light to enhance photoreception, and an avoidance response, in which they move away from strong light to avoid photodamage. Although chloroplast photorelocation has been extensively studied in model plants such as Arabidopsis thaliana, little is known about this process in the economically important crop strawberry. Here, we investigated chloroplast photorelocation in leaf mesophyll cells of wild strawberry (Fragaria vesca), a diploid relative of commercially cultivated octoploid strawberry (F. × ananassa). Microscopy observation revealed that the periclinal area of leaf mesophyll cells in F. vesca is considerably smaller than that of A. thaliana. Given this small cell size, we investigated chloroplast photorelocation in F. vesca by measuring light transmittance in leaves. Weak blue light induced the accumulation response, whereas strong blue light induced the avoidance response. Unexpectedly, strong red light also induced the accumulation response in F. vesca. These findings shed light on chloroplast photorelocation as an intracellular response, laying the foundation for enhancing photosynthesis and productivity in Fragaria.

Optimization of natural rubber foams: Effect of foaming agent content and processing conditions on the cellular structure and mechanical properties

In the past decades, natural rubber (NR) foams became popular in the automotive, construction and aerospace industries because of their lightweight, flexibility and shock-absorbing properties. The selection of optimal formulation and processing parameters is critical to produce foam with specific properties depending on the application. In this study, the effect of foaming agent concentration, foaming temperature and time on the morphological and mechanical properties of NR foams was investigated. First, increasing the foaming agent content from 5 to 9 phr (parts per hundred rubber) increased the cell size (16%), while decreasing the compression modulus (28%). In the second part, increasing the foaming temperature (145 to 155°C) resulted in larger cell size (163%); while decreasing the cell density (28%), compression modulus (2%), and hardness (1%). In the third part, increasing the foaming time (25 to 45 min) led to smaller cell size (63%) combined with higher cell density (100%), compression modulus (16%), and hardness (3%). Based on all the results obtained, the best NR foam was obtained with 7 phr of foaming agent and produced at 150°C for 35 min leading to superior morphological and mechanical performance: the smallest cell size (25 µm) and the most uniform cell size distribution ( Đ = 1.03) generating the highest compression modulus (3.36 MPa). Finally, the experimental compression results were combined to build a nonlinear regression model to optimize the formulation and processing conditions leading to 6.5 phr of OBSH molded at 150°C for 36 min. The model showed good agreement with a validation test with less than 2% deviation observed for both compression modulus and strength.

Abstract P280: Understanding the Association Between Resilience Factors and Lifestyle-Based CVD Prevention Among Young Adults in Puerto Rico

Background: Recent research has identified associations between optimism and cardiovascular disease endpoints. However, other resilience factors like shift-and-persist (SP; adapting the self to stress while finding purpose in tough times), spirituality, social support, and life satisfaction have been understudied. We assessed associations among these factors and a lifestyle-based CVD metric (the Fuster BEWAT score (FBS)) and identified the strongest predictor among young adults in Puerto Rico (PR), a population with a high burden of CVD risk factors. Methods: This cross-sectional analysis used data from young adults (18-29y) who underwent survey and clinical assessments (September 2020-September 2023 ) as part of the PR-OUTLOOK study. Those with complete data were included (n=1,721; 61% female). SP was measured with the Chen scale, optimism with the Life Orientation Test-Revised-6 items scale, spirituality with the Daily Spiritual Experiences Scales, social support (from friends, family, and partner) with the Whalen scale, and life satisfaction with one item from the International Social Survey Program. Higher scores in all scales represent greater resilience and all were converted to z-scores. The FBS included blood pressure, exercise, weight, diet, and tobacco. All metrics were dichotomized as ideal (1) or non-ideal (0) and a total FBS was calculated and categorized according to the number of ideal metrics: poor (0-1), intermediate (2-3), and ideal (≥4). The intermediate and ideal groups were grouped for analysis due to small cell size. Logistic regression models assessed the association between each resilience factor and intermediate/ideal FBS (vs. poor) adjusting for socio-demographics, health insurance, and depression symptoms (Model 1), and for all other resilience factors (Model 2). Results: In the sample, 46% had a poor FBS score, 53% had an intermediate score, and 1% achieved an ideal score. In Model 1, a one standard deviation increase in SP was associated with a 21% higher odds of intermediate/ideal FBS (OR=1.21; 95% CI=1.08-1.36), while optimism, life satisfaction, and social support were associated with 17% (OR=1.17; 95% CI=1.05-1.32), 15% (OR=1.15; 95% CI=1.03-1.29), and 12% (OR=1.12; 95% CI=1.01-1.25) higher odds, respectively. Upon adjusting for all resilience factors (Model 2), only SP remained significantly associated with intermediate/ideal FBS (OR=1.17, 95% CI=1.01-1.35). Conclusion: While optimism, life satisfaction, and social support demonstrated initial associations with better FBS scores, SP emerged as the most significant resilience factor predicting FBS. If confirmed with longitudinal studies, SP could be an important target for future studies of CVD prevention interventions.

Effects of process conditions and nano-fillers on the cell structure and mechanical properties of co-injection molded polypropylene-polyethylene composites

Compared with traditional injection foaming, co-injection foaming serves as a method to prepare products with high-quality surfaces and enhanced mechanical properties, demonstrating excellent technical advantages and economic benefits. The effects of high-density polyethylene (HDPE) content, foaming agent content, melting temperature of core material, and nano-organic montmorillonite (OMMT) content on the cell structure, mechanical properties, and crystallization behavior of isotactic polypropylene (iPP)/HDPE composite foam prepared by co-injection foaming were systematically studied. At a foaming agent content of 2 wt.%, HDPE content of 30 wt.%, OMMT content of 3 wt.%, and the melting temperature of core material of 190 °C, the composite foam exhibited a cell size measuring 85 μm, a cell density of 2.5 × 105 cells/cm3, a tensile strength of 25.8 MPa, and an impact strength of 12.5 kJ/m2. The addition of HDPE reduced the crystallinity of iPP matrix, while enhancing the solubility of carbon dioxide within the matrix. The non-miscible interface between HDPE and iPP helped reduce the energy barrier for cell nucleation. Furthermore, the introduction of OMMT as a nucleating agent in iPP/HDPE composite material dramatically decreased the energy barrier for cell nucleation. These synergistic effects result in foam with the smaller cell size and the higher cell density, exhibiting excellent comprehensive mechanical properties. This work provides a feasible method for preparing composite foam with excellent comprehensive performance.

Biobased Immiscible Polylactic Acid (PLA): Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) Blends: Impact of Rheological and Non-isothermal Crystallization on the Bead Foaming Behavior

Nowadays, bead foams are of great interest due to their high lightweight potential. The processing of such foams strongly depends on the crystallization and rheological behavior of the polymers used. By blending polymers, these properties can be tailored to obtain beaded foams with low density, small cell size and high cell density. As a bio-based polymer, PLA is of great interest due to its renewable carbon source. PLA suffers from its low thermal and rheological properties, which can be compensated by using blends. The correlation between the PLA/PHBV ratio and the rheological as well as the crystallization behavior was investigated. The use of PHBV as a minor phase significantly changes the rheological properties and increases the crystallization behavior of PLA. These findings were applied to the foam extrusion process to obtain low density bead foams. Bead foams with densities below 100 kg/m3, mean cell sizes below 50 µm and cell densities of 1 × 107 cells/cm3 were obtained.

Grazing strategies determine the size composition of phytoplankton in eutrophic lakes

AbstractAlthough the general impacts of zooplankton grazing on phytoplankton communities are clear, we know comparatively less about how specific grazing strategies interact with environmental conditions to shape the size structure of phytoplankton communities. Here, we present a new data‐driven, size‐based model that describes changes in the size composition of lake phytoplankton under various environmental constraints. The model includes an ecological trade‐off emerging from observed allometric relationships between (1) phytoplankton cell size and phytoplankton growth and (2) phytoplankton cell size and zooplankton grazing. In our model, phytoplankton growth is nutrient‐dependent and zooplankton grazing varies according to specific grazing strategies, namely, specialists (targeting a narrow range of the size‐feeding spectrum) vs. generalists (targeting a wide range of the size‐feeding spectrum). Our results indicate that grazing strategies shape the size composition of the phytoplankton community in nutrient‐rich conditions, whereas inorganic nutrient concentrations govern phytoplankton biomass. Under oligotrophic regimes, the phytoplankton community is dominated by small cell sizes and the grazers have little to no impact. Under eutrophic regimes, dominating specialist grazers push phytoplankton towards small cells, whereas dominating generalist grazers push phytoplankton towards large cells. Our work highlights that trait‐based modeling, based on realistic eco‐physiological trade‐offs, represents a valuable tool for disentangling the interactive roles played by nutrient regimes and grazing strategies in determining the size compositions of lake phytoplankton. Ultimately, our study offers a quantitative basis for understanding how communities of lake phytoplankton may reorganize in the future in response to changes in nutrient levels and zooplankton grazing strategies.

Effects of borderline personality disorder symptoms on dialectical behavior therapy outcomes for eating disorders.

Existing literature on the effects of borderline personality disorder (BPD) and eating disorder (ED) comorbidity in terms of clinical presentation and treatment outcome has been limited and inconclusive. The present study examined whether clients with EDs and varying levels of BPD symptoms presented with more severe ED symptoms at admission, and whether they responded to dialectical behavior therapy (DBT)-based treatment. Participants (N = 176) were adults in a DBT-based partial hospitalization program for EDs at an academic medical center. Participants completed self-report measures at admission, 1-month postadmission, discharge, and 6-month follow-up. Results suggested that patients with elevated BPD symptoms at admission had greater ED symptoms during treatment, evidenced by small to moderate effect sizes. However, patients with high BPD symptoms demonstrated steeper declines in binge eating, fasting, and parasuicidal behavior early during treatment compared to patients with low BPD symptoms. Individuals with high BPD symptoms at admission (i.e., probable BPD diagnosis) were as likely to meet remission criteria and relapse as individuals with low BPD symptoms, though this null finding may be influenced by small cell sizes. Our findings also suggest that DBT skills use does not predict changes in symptoms. In sum, our findings suggest that while clients with higher BPD symptoms may improve during DBT-based partial hospitalization, their ED symptoms may remain more severe. Future studies are needed to determine whether adjunctive treatments improve outcomes for clients with EDs and comorbid BPD symptoms in DBT programs and whether skills use quality is a better predictor of ED symptom changes. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Enhancing Long-Term Durability of Electrochemical Reactors Producing Formate from CO2 and Water Designed for Integration with Solar Cells.

Artificial photosynthetic cells producing organic matter from CO2 and water have been extensively studied for carbon neutrality, and the research trend is currently transitioning from proof of concept using small-sized cells to large-scale demonstrations for practical applications. We previously demonstrated a 1 m2 size cell in which an electrochemical (EC) reactor featuring a ruthenium (Ru)-complex polymer (RuCP) cathode catalyst was integrated with photovoltaic cells. In this study, we tackled the remaining issue to improve the long-term durability of cathode electrodes used in the EC reactors, demonstrating high Faradaic efficiencies exceeding 80% and around 60% electricity-to-chemical energy-conversion efficiencies of a 75 cm2 sized EC reactor after continuous operation for 3000 h under practical conditions. Introduction of a pyrrole derivative containing an amino group in the RuCP coupled with UV-ozone treatment to create carboxyl groups on the carbon supports effectively reduced the detachment of the RuCP catalyst by forming a strong amide linkage. A newly developed chemically resistant graphite adhesive prevented the carbon supports from peeling off of the conductive substrates. In addition, highly durable anodes composed of IrOx-TaOy/Pt-metal oxide/Ti were adopted. Even though the EC reactor was installed at an inclined angle of 30°, which is approximately the optimal angle for receiving more solar energy, the crossover reactions were sufficiently suppressed because the porous separator film impeded the transfer of oxygen gas bubbles from the anode to the cathode. The intermittent operation improved the energy-conversion efficiency because the accumulated bubbles were removed at night.

Marine Heat Waves in the Indian Ocean: A Major Climate Impact on Marine Microalgae

A clearly defined, lengthy (five days or longer) period of extraordinarily high ocean temperatures is known as Marine Heat Waves (MHWs) (above the e0th percentile). These events significantly impact the structure, abundance, cell size, metabolic functions, physico-chemical interactions between microalgae cells and their surroundings in the Indian Ocean. In the tropical Indian Ocean, the average sea surface temperature (SST) increased by 1.0°C (0.15°C/decade) on average between 1951 and 2015, while the global average SST warmed by roughly 0.7°C (0.11 °C/decade). This resulted from the incidence of Marine microalgal bloom MMBs (including Harmful Algal Bloom) and the number of causal taxa may grow as SST increases. Trichodesmium and Noctiluca contributed 34.4% and 31.8%, respectively, to the overall blooms. Such a heating phenomenon also triggers the dominance of small-sized algal cells, harmful diatoms and pico-plankton. The present paper reviews the Indian as well as global episodes of MHWs such as Western South Atlantic, North-East Pacific, Western Australia, Alaskan Sea etc. and their impact on phytoplankton. The combination of warming and heatwaves triggers blooms of buoyant cyanobacteria and its combined impacts of MHWs and ocean warming/acidification on phytoplankton community structure have not been fully studied in the Indian Ocean.

The rise of single-cell transcriptomics in yeast.

The field of single-cell omics has transformed our understanding of biological processes and is constantly advancing both experimentally and computationally. One of the most significant developments is the ability to measure the transcriptome of individual cells by single-cell RNA-seq (scRNA-seq), which was pioneered in higher eukaryotes. While yeast has served as a powerful model organism in which to test and develop transcriptomic technologies, the implementation of scRNA-seq has been significantly delayed in this organism, mainly because of technical constraints associated with its intrinsic characteristics, namely the presence of a cell wall, a small cell size and little amounts of RNA. In this review, we examine the current technologies for scRNA-seq in yeast and highlight their strengths and weaknesses. Additionally, we explore opportunities for developing novel technologies and the potential outcomes of implementing single-cell transcriptomics and extension to other modalities. Undoubtedly, scRNA-seq will be invaluable for both basic and applied yeast research, providing unique insights into fundamental biological processes.

A novel method for preparing anisotropic negative Poisson's ratio composite foam with excellent structural stability and shape recovery property

Negative Poisson's ratio (NPR) foams are usually prepared by the transformation of positive Poisson's ratio (PPR) foams with honeycomb cell structure, which face a challenge for restraining the increase in volume and Poisson's ratio once they are stimulated by high temperature. In addition, they cannot restore to its reentrant structure after large deformation. In this work, a novel method for preparing anisotropic NPR foam with excellent structural stability and shape recovery property is established by synergistically controlling hierarchical pore structures. The obtained NPR silicone rubber/polylactic acid (SR/PLA) composite foam has large-size holes (auxetic structure) with concave hexagonal shape and small-size honeycomb cells, which are generated by 3D printing technology and salt leaching method, respectively. The auxetic structure with the orientation characteristic is directly formed rather than transformed from the honeycomb cell structure. Therefore, the dimension and Poisson's ratio value of the NPR SR/PLA composite foam keep constant after high temperature heating treatment, meaning an excellent structural stability. Furthermore the excellent shape recovery property of the NPR SR/PLA composite foam endows it restore to the initial auxetic structure after large deformation to a large extent. It should be mentioned that the anisotropy of the NPR SR/PLA composite foam further will bring a broad application prospect in the field of human body cushioning materials, such as prosthetic lining sleeve.

MXene/PDMS composite foam with regulatable cell structures for improved EMI shielding performance

AbstractThe construction of conductive network and the design of material structure are the key points of polymer‐based shielding materials. Herein, we reported a MXene/PDMS composite foam material with adjustable cell structure and high efficiency electromagnetic interference (EMI) shielding. Few‐layered MXene is used as a conductive filler to construct three‐dimensional conductive networks by in situ chemical etching. Meanwhile, a series of polystyrene microspheres with different sizes were prepared by applying suspension polymerization method as templates to introduce different cell sizes and densities for PDMS‐based materials. The density and EMI shielding performance of composites can be improved by adjusting the cell structure. Compared with the unfoamed MXene/PDMS composites, the composite foam in this work not only reduces the material density greatly but also improves the microwave absorption performance with smaller cell size. This method provides a simple and effective guide for changing material density and absorbing mechanism by introducing cell structure into polymer‐based materials in the future.

Molecular dynamics simulations of a nanobubble’s collapse-induced erosion on nickel boundary and porous nickel foam boundary

Nickel (Ni) alloys and their foam composites are extensively acknowledged materials utilized in the construction of propellers and hulls for the shipbuilding industry. Erosion caused by bubble collapse, a well-documented form of damage on ship rudders, propellers and hulls, can alter the physical properties of Ni and its foam, consequently constraining their potential applications. The present study aims to investigate the process of nanobubble collapse and its impact on the mechanical and thermal properties of Ni boundary and porous Ni foam boundary. To achieve this, a molecular dynamics (MD) simulations was used to study nanobubble collapse dynamics near the boundaries. Results indicated that the nanobubble collapses due to the contrasting pressure and velocity at the interface between the shock wave and the nanobubble surface. As the nanobubble collapses, its volume decreases, resulting in the formation of a water nano-hammer with a pressure and temperature of approximately 30 GPa and 5000 K. The high impact of the nano-hammer leads to erosion in the case of the Ni boundary and compression in the porous Ni foam boundary. The mechanical stability of an eroded Ni boundary decreases due to the creation of dislocations under the impact of the nano-hammer. However, the thermal stability of the Ni boundary remains relatively unaffected by the erosion process. The compressed Ni foam boundary exhibits a lower specific surface area, smaller cell size, and shorter struts compared to the uncompressed Ni foam boundary, resulting in increasing of the mechanical and thermal stability.

Cell Size Effects and Distinct Current Conduction Behaviors for Hafnium‐Oxide‐Based Selectors with Vanadium as Top Electrode

Selector devices have been incorporated in the resistance random access memory to realize one‐selector‐one‐resistor device for the achievement of high‐density storage applications. Among many possible materials for selector devices, the metal–insulator transition mechanism of the vanadium oxide (VOx) is interesting due to its formation under the influence of temperature. Previous studies have also indicated that VOx is formed after high‐temperature annealing. Herein, the V/HfO2/TiN with different deice cell sizes is investigated. After the forming process, devices with small cell sizes can exhibit threshold switching (TS) characteristics, while devices with large cell sizes can show resistive switching property. Electrical measurements of DC and AC operations are also conducted to verify stable TS characteristics for selector applications. The current fitting method and the computer‐aid simulation are also carried out to compare different current conduction behaviors of devices with large and small cell sizes, which indicates that heat plays an important role in the formations of VOx layer of the V/HfO2/TiN device.

Exploring the influence of size-related factors on geocell-reinforced soil response using coupled continuum-discontinuum analysis

Size-related factors, such as the dimensions and cell count of geocell, play a crucial role in determining the effectiveness of soil reinforcement. In this study, a 3D coupled framework that leverages the strengths of both continuum and discontinuum methods was developed to investigate the influence of pocket size and multi-cell configuration on geocell-reinforced soils. To unveil the impact of size-related factors on soil-geocell interactions, reinforced soils containing various geocell configurations (single large-sized cell, multiple small-sized cells), as well as geocell-free soils subjected to increasing levels of confining pressure were extensively examined. This thorough investigation aimed to establish correlations between macroscopic responses and underlying micromechanical mechanisms. Our findings revealed that the presence of the geocell not only enhances the densification of interparticle contacts and reduces the number of floating particles that contribute minimally to load support, but also facilitates the concentration of force chains within the geocell structure. This leads to an increase in elastic stiffness along the loading axis. These observations highlight that the geocell's confining mechanism enhances both the load-carrying capacity and the infill rigidity, thereby preventing lateral soil spreading. In essence, the geocell serves to increase the soil's ability to withstand load and maintain its structural integrity laterally.