The genetic diversity among strawberry breeding resources based on SSRs

Cultivated strawberry (Fragaria × ananassa Duch.) is a high value horticultural crop. In this study, the genetic diversity of 160 strawberry accessions was determined using five highly polymorphic simple sequence repeat (SSR) markers. Sixty different alleles were identified, with allele frequencies in the range of 0.006 to1. Similarity scores were in the range of 0.034 to 0.963 (average: 0.507). The accessions were categorized into five groups. Group 1 contained two diploid Fragaria vesca species and one unknown accession. Group 2 contained one accession (F x ananassa). Group 3 contained 20 F × ananassa accessions and six unknown accessions. Group 4 contained 48 F. × ananassa accessions, one octaploid Fragaria chiloensis species, and six unknown accessions while Group 5 contained 69 F. × ananassa accessions and six unknown accessions. Accessions within a pedigree were frequently grouped together. A total of 30 novel accessions were categorized alongside existing accessions. These results will allow breeders to develop strategies which incorporate more genetic diversity into new cultivars

Hydrogen Sensing Performance of ZnO Schottky Diodes in Humid Ambient Conditions with PMMA Membrane Layer

Enhanced hydrogen sensing performance of Pt Schottky diodes on ZnO single crystal wafers in humid ambient conditions is reported using a polymethylmethacrylate (PMMA) membrane layer. ZnO diode sensors showed little change in forward current when switching to wet ambient H2 conditions with 100% relative humidity. This sensitivity drop in the presence of water vapor can be attributed to surface coverage of hydroxyl groups on the Pt surface in humid ambient conditions. The hydrogen sensitivity of PMMA-coated diode sensors recovered up to 805% in wet H2 ambient conditions at room temperature. The PMMA layer can selectively filter water vapor and allow H2 molecules to pass through the membrane layer. It is clear that the PMMA layer can effectively serve as a moisture barrier because of low water vapor permeability and its hydrophobicity. In both dry and wet conditions, ZnO diodes exhibited relatively fast and stable on/off switching in each cycle with good repeatability

Why and What to Teach: AI Curriculum for Elementary School

With the rapid technological change of society with Artificial Intelligence, elementary schools' goal should be to prepare the next generations according to competencies. We propose an AI curriculum to cultivate students' AI literacy to answer the question of ‘why and what to teach’ on AI. The proposed AI curriculum focuses on achieving AI literacy based on three competencies: AI Knowledge, AI Skill, and AI Attitude. We anticipate that the proposed curriculum will equip students with core competencies for the future with AI

Transfer-Free Growth of Multilayer Graphene Using Self-Assembled Monolayers

Large-area graphene needs to be directly synthesized on the desired substrates without using a transfer process so that it can easily be used in industrial applications. However, the development of a direct method for graphene growth on an arbitrary substrate remains challenging. Here, we demonstrate a bottom-up and transfer-free growth method for preparing multilayer graphene using a self-assembled monolayer (trimethoxy phenylsilane) as the carbon source. Graphene was directly grown on various substrates such as SiO₂/Si, quartz, GaN, and textured Si by a simple thermal annealing process employing catalytic metal encapsulation. To determine the optimal growth conditions, experimental parameters such as the choice of catalytic metal, growth temperatures, and gas flow rate were investigated. The optical transmittance at 550 nm and the sheet resistance of the prepared transfer-free graphene are 84.3% and 3500 Ω/□, respectively. The synthesized graphene samples were fabricated into chemical sensors. High and fast responses to both NO₂ and NH₃ gas molecules were observed. The transfer-free graphene growth method proposed in this study is highly compatible with previously established fabrication systems, thereby opening up new possibilities for using graphene in versatile applications

Ternary Pt−Fe−Co Alloy Electrocatalysts Prepared by Electrodeposition: Elucidating the Roles of Fe and Co in the Oxygen Reduction Reaction

An electrodeposition-based protocol for the synthesis of ternary Pt−Fe−Co electrocatalysts for the oxygen reduction reaction (ORR) has been developed. The eletrodeposition method suits the purpose of fast catalyst screening and mechanism studies. Here, we survey the composition effect of Fe and Co atoms in ternary Pt−Fe−Co alloy electrocatalysts on the electrocatalytic activity toward the ORR in terms of geometric (Pt−Pt distance) and electronic (core-level binding energy, d-band center) aspects. A wide range of Pt−Fe−Co catalysts can easily be obtained using electrodeposition under simple and mild conditions. Among the various compositions, Pt85Fe10Co5 catalyst shows excellent mass activity that is 3.5 times higher than that of pure Pt. Interestingly, the ORR kinetic current density reveals a double-volcano plot as a function of alloy composition. Extended X-ray absorption fine structure (EXAFS) spectroscopy and high-resolution X-ray photoelectron spectroscopy (HRXPS) experiments were conducted to explain the abnormal double-volcano behavior. The results also reveal that the d-band center of Pt85Fe10Co5 is downshifted by about 0.1 eV compared to that of Pt, which explains its superior activity toward the ORR.11Nsciescopu

Influence of High-Energy Proton Irradiation on β‑Ga₂O₃ Nanobelt Field-Effect Transistors

The robust radiation resistance of wide-band gap materials is advantageous for space applications, where the high-energy particle irradiation deteriorates the performance of electronic devices. We report on the effects of proton irradiation of β-Ga₂O₃ nanobelts, whose energy band gap is ∼4.85 eV at room temperature. Back-gated field-effect transistor (FET) based on exfoliated quasi-two-dimensional β-Ga₂O₃ nanobelts were exposed to a 10 MeV proton beam. The proton-dose- and time-dependent characteristics of the radiation-damaged FETs were systematically analyzed. A 73% decrease in the field-effect mobility and a positive shift of the threshold voltage were observed after proton irradiation at a fluence of 2 × 10¹⁵ cm^–2. Greater radiation-induced degradation occurs in the conductive channel of the β-Ga₂O₃ nanobelt than at the contact between the metal and β-Ga₂O₃. The on/off ratio of the exfoliated β-Ga₂O₃ FETs was maintained even after proton doses up to 2 × 10¹⁵ cm^–2. The radiation-induced damage in the β-Ga₂O₃-based FETs was significantly recovered after rapid thermal annealing at 500 °C. The outstanding radiation durability of β-Ga₂O₃ renders it a promising building block for space applications

Ohmic contacts on n-type β-Ga2O3 using AZO/Ti/Au

AZO interlayers between n-Ga2O3 and Ti/Au metallization significantly enhance Ohmic contact formation after annealing at ≥ 300°C. Without the presence of the AZO, similar anneals produce only rectifying current-voltage characteristics. Transmission Line Measurements of the Au/Ti/AZO/Ga2O3 stacks showed the specific contact resistance and transfer resistance decreased sharply from as-deposited values with annealing. The minimum contact resistance and specific contact resistance of 0.42 Ω-mm and 2.82 × 10-5 Ω-cm2 were achieved after a relatively low temperature 400°C annealing. The conduction band offset between AZO and Ga2O3 is 0.79 eV and provides a favorable pathway for improved electron transport across this interface

Effects of stabilizers on the synthesis of Pt3Cox/C electrocatalysts for oxygen reduction

Pt3Cox/C electrocatalysts for use as cathodes in proton exchange membrane fuel cells are fabricated using various stabilizers to control the different reduction speeds between Pt and Co ions. Four different types of stabilizers—sodium acetate, oleylamine, tetraoctylammonium bromide (TOAB), and hexadecyltrimethylammonium bromide (CTAB)—differing in molecular structures and ionic states are tested. Primarily, Pt3Cox/C alloy nanoparticles are synthesized with 0.6 < x < 0.8 after heat treatment to remove the residual stabilizers. A significant improvement in the activity for oxygen reduction reaction is observed in the case of TOAB- and CTAB-mediated Pt3Cox/C catalysts. In particular, CTAB-mediated catalysts exhibit the best activity, which is about 2-times higher mass activity than commercial Pt/C catalyst. The higher mass activity is believed to result from not only the alloying effects with small atomic size Co but also better dispersion and smaller particle size after heat treatment at relatively low temperature.11Nsciescopu

Liquid Slip on a Nanostructured Surface

We explored a liquid slip, referred to as the Navier slip, at liquid–solid interface. Such a slip is provoked by the physicochemical features of the liquid–solid system. The goal of this study was to investigate the effect of a nanoengineered surface structure on liquid slip by fabricating the self-assembly structure of nano Zinc oxide (<i>n-ZnO</i>). We have also examined how the liquid–solid surface interaction controlled by hydrophobic chemical treatment affects the liquid slip. The findings showed that liquid slip increases with decreasing the characteristic length scales (e.g., channel height and depth), resulting in drag reduction. It was also found that dewetted (Cassie) state due to the generation of air gap developed by <i>n-ZnO</i> was more critical for the liquid slip than the minimization of interface interaction. The linear and nonlinear Navier slip models showed that liquid slip behavior is more obvious when increasing the nonlinearity. This study will contribute to understanding of the underlying physics behind fluid slip phenomena, such as the Navier slip for Newtonian liquids and Maxwell’s slip for Newtonian gases