Journal of the Korean Physical Society最新文献

{"title":"IoT sensor-based systems in real-time monitoring of health and environment: a review","authors":"S. Sreejith,&nbsp;Asisa Kumar Panigrahy,&nbsp;J. Ajayan,&nbsp;J. M. Radhika,&nbsp;N. V. Raghavendra Reddy,&nbsp;N. V. Uma Reddy,&nbsp;S. Umamaheswaran","doi":"10.1007/s40042-025-01378-7","DOIUrl":"10.1007/s40042-025-01378-7","url":null,"abstract":"<div><p>Over the past few years<b>,</b> Internet of Things (IoT) has surfaced as an effective technology which helps in interconnecting objects and computing devices together. Enormous potential of IoT has helped in providing more convenient and high-quality services for many day-to-day applications. Tangible objects can be connected to internet through IoT which enables rapid reception and transmission of data. Significant advancement of IoT technology further helps in connecting different smart objects via internet as well as facilitates in providing better methods for data interoperability. In many large-scale applications like healthcare monitoring, environment monitoring, smart agriculture, smart cities, smart grids, smart factories etc., IoT is playing a significant role. Machine learning, embedded systems, real-time analytics and sensors have influenced the concept of IoT. IoT sensors help in providing improved communication without the necessity for human-to-human and human-to-computer interface. This article critically analyzes various IoT sensor-based systems used in medical surveillance and in monitoring of air and water quality. The article reviews the state-of-the-art developments, real word application, and key technologies in these domains. The performance of various IoT sensor-driven systems used for monitoring in real time were also meticulously studied. </p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"87 1","pages":"1 - 27"},"PeriodicalIF":0.9,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145144195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On-chip electrical excitation of micromembrane for fully integrated high-frequency, multi-mode optomechanical resonator","authors":"Sungwan Cho,&nbsp;Myunglae Jo,&nbsp;Sanggoon Kim,&nbsp;Yun Daniel Park,&nbsp;Seung Bo Shim","doi":"10.1007/s40042-025-01368-9","DOIUrl":"10.1007/s40042-025-01368-9","url":null,"abstract":"<div><p>A micromembrane mechanical resonator was fabricated from stoichiometric silicon nitride. Its resonant motion was actuated using an electrical field gradient force generated by electrodes adjacent to the oscillating structure, eliminating the need for electrodes directly on the movable membrane, thereby preserving a high-quality factor. This method enables investigation of multiple modes of the micromembrane, up to the 32^nd mode with a resonant frequency of 78 MHz, using optical measurement technique. The absence of a substrate beneath the membrane makes the structure compatible with optical cavities. This compatibility is crucial for cavity-optomechanical systems, which require integration of mechanical devices with high-finesse optical cavities. Furthermore, by applying phase-shifted RF signals, symmetric modes at the similar resonant frequency can be separated and analyzed. The high-frequency and multi-mode operation, coupled with the substrate-free design makes this micromembrane resonator a promising candidate for applications in optical signal processing, optical component integration with high-finesse cavities, and exploration of cavity optomechanics.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"87 1","pages":"28 - 34"},"PeriodicalIF":0.9,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145144197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cool-down simulation of a two-stage cryocooler in magnetic resonance superconducting magnet with conduction-cooled design","authors":"Zhiqiang Long,&nbsp;Likai Huang,&nbsp;Jie Zhu,&nbsp;Guoqing Liu,&nbsp;Zhengxin Wu,&nbsp;Qiang Yan","doi":"10.1007/s40042-025-01381-y","DOIUrl":"10.1007/s40042-025-01381-y","url":null,"abstract":"<div><p>Cryogen-free superconducting magnets have become increasingly popular in research and industry. In this work, a cryogenic system was developed to realize rapid cooling of copper plate in conduction-cooled superconducting magnet applied to magnetic resonance imaging (MRI) systems. A full three-dimensional method based on the heat conduction and thermal radiation models was used for predicting heat transfer characteristics inside the device, and the effects of structural connection and dimension on initial cool-down time were also investigated. Simulation results indicated that the temperature of the copper sample plate decreased almost linearly with the increase in cooling time at first and then decreased rapidly due to the proliferated thermal conductivity of copper. The number of thermal links has less effect on initial cool-down time when the number exceeds eight. The initial cool-down time is sensitive to the spacing of the two stages of a cryocooler, with increasing efficiency by about 10% as the spacing increases from 80 to 320 mm. The larger cooling power of first-stage thermal anchor could be a key factor in boosting efficiency. The simulation results were in good agreement with the experimental data and had the potential to achieve low energy consumption and high efficiency of cooling of MRI low-temperature superconducting magnet in practical applications.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"87 1","pages":"106 - 113"},"PeriodicalIF":0.9,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145143674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation of the effect of high-voltage frequency on the density of RONS species in the air atmospheric pressure gas discharge","authors":"Fariborz Momtazzadeh,&nbsp;Farshad Sohbatzadeh,&nbsp;Hamed Soltani Ahmadi,&nbsp;Ramin Mehrabifard","doi":"10.1007/s40042-025-01392-9","DOIUrl":"10.1007/s40042-025-01392-9","url":null,"abstract":"<div><p>In the last few decades, studies in various fields of plasma technology have expanded and its application in different processes has increased. Therefore, the achievement of a desirable and practical plasma with specific characteristics is of particular importance. The frequency of the applied voltage is one of the important factors that play a role in the physical and chemical characteristics. In this research, changes in the density of active species produced in an electrical discharge using a dielectric barrier and air working gas have been investigated, from a frequency of 500 Hz to 500 kHz, and by applying a constant voltage of 2 kV, have been investigated. For this purpose, 87 different reactions with specific collision cross-sections were defined in COMSOL Multiphysics. Other parameters, including current–voltage waveform, electric field, species density including <span>({text{NO}})</span>,<span>({text{OH}})</span>,<span>({text{O}}_{2}^{ + })</span>,<span>({text{O}}_{3})</span>, etc., were evaluated. The results show that under completely identical conditions, the electron temperature distribution changes with increasing applied frequency, and the density of reactive oxygen and nitrogen species (RONS) like (<span>({text{NO}})</span>, <span>({text{OH}})</span>, <span>({text{O}}_{3})</span>,..) decreases, but <span>({text{O}}_{2}^{ + })</span> shows an increasing trend. It should be noted that the simulation results are in good agreement with the previous experimental and simulation reports. These results offer valuable insights into optimizing plasma parameters for different applications, potentially resulting in better treatment outcomes across a range of therapeutic domains.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"87 1","pages":"35 - 46"},"PeriodicalIF":0.9,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145143673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of highly efficient and stable spin polarimeter for an undulator-based angle-resolved photoemission spectroscopy beamline","authors":"Minki Sung,&nbsp;Jiwon Jung,&nbsp;Dongjoon Jeong,&nbsp;Hyunjin Jung,&nbsp;Han Woong Yeom,&nbsp;Roland Stania,&nbsp;Sangjun Park,&nbsp;Jaeyoung Kim","doi":"10.1007/s40042-025-01385-8","DOIUrl":"10.1007/s40042-025-01385-8","url":null,"abstract":"<div><p>Highly efficient and reliable spin- and angle-resolved photoelectron spectroscopy (spin-ARPES) has been developed at the 4A2 beamline of Pohang Light Source II. The spin polarimeters based on exchange scattering by a ferromagnetic target were integrated into a <i>state-of-the-art</i> hemispherical electron analyzer, enabling us to obtain the electronic band structure with a three-dimensional spin polarization character. The figure of merit (FOM) of the spin polarimeter was proven to be higher than those of conventional Mott detectors by two orders. The spin-dependent electron reflectivity spectra of in situ grown ferromagnetic targets were obtained by the use of a kinetic energy control lens and they are utilized to optimize and stabilize the spin detection asymmetry. The overall performance was demonstrated by measuring the spin-ARPES spectra of the Dirac cone of <span>(hbox {Bi}_2 hbox {Se}_3)</span>. </p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"87 1","pages":"74 - 78"},"PeriodicalIF":0.9,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145143331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase transitions of thermoelectric FexCu12−xSb4Se13","authors":"Hyeon-Sik O,&nbsp;Sang Jun Park,&nbsp;Il-Ho Kim","doi":"10.1007/s40042-025-01379-6","DOIUrl":"10.1007/s40042-025-01379-6","url":null,"abstract":"<div><p>Cu–Sb–Se ternary chalcogenide compounds have garnered interest as potential thermoelectric materials because of their low cost and environmental benefits. Among these, Cu₁₂Sb₄Se₁₃ (hakite), Cu₃SbSe₄ (permingeatite), Cu₃SbSe₃ (bytizite), and CuSbSe₂ (pribramite) stand out as promising candidates because of their narrow band gaps and low thermal conductivity. However, Cu₁₂Sb₄Se₁₃ is unstable in its pure form because of a charge imbalance in its structure, where all copper atoms exist in the monovalent state (Cu⁺). This instability restricts its potential for thermoelectric applications. In this study, we sought to stabilize Cu₁₂Sb₄Se₁₃ by partially substituting Fe²⁺ ions for Cu⁺ ions, aiming to compensate for the charge imbalance and synthesize Fe_xCu_{12<b>−</b>x}Sb₄Se₁₃ (0.5 ≤ <i>x</i> ≤ 2). X-ray diffraction analysis revealed that adding Fe led to the formation of bytizite and CuFeSe₂ (eskebornite), with the pribramite phase emerging as the Fe content increased. Thermal analysis using differential scanning calorimetry revealed that for samples with Fe content between <i>x</i> = 0.5 and 1.5, bytizite and permingeatite phases coexisted. In the Fe₂Cu₁₀Sb₄Se₁₃ sample, three phases were identified: bytizite, permingeatite, and pribramite. This suggests that synthesizing hakite through charge compensation with Fe was not feasible, as Fe substitution resulted in multiple phase formations rather than stabilizing the hakite phase. In terms of thermoelectric properties, the FeCu₁₁Sb₄Se₁₃ sample exhibited a power factor of 80 μWm⁻¹K⁻² and a maximum figure of merit (<i>ZT</i>) of 0.14 at 623 K.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"86 12","pages":"1176 - 1187"},"PeriodicalIF":0.9,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strong electron-occupancy dependence of the lever arm in few-electron quantum dot systems","authors":"Uhjin Kim,&nbsp;Seokyeong Lee,&nbsp;Myunglae Jo,&nbsp;Hyung Kook Choi","doi":"10.1007/s40042-025-01388-5","DOIUrl":"10.1007/s40042-025-01388-5","url":null,"abstract":"<div><p>We quantitatively investigated the variation of gate lever-arm (<span>(alpha)</span>) in quantum dot (QD) systems, focusing on its dependence on electron occupancy. The values of <span>(alpha)</span> were obtained from Coulomb diamond measurements in a single quantum dot (SQD) and from the analysis of bias triangles near triple points in a double quantum dot (DQD) under finite DC bias. Utilizing charge sensor (CS) enabled clear detection of charge transitions even at low electron occupancies, revealing that the <span>(alpha)</span> increases substantially as the electron number decreases. For the SQD, <span>(alpha)</span> increased from <span>(28 text{meV}/text{V})</span> with six electrons to <span>(48 text{meV}/text{V})</span> in the single-electron regime − nearly 70% relative change − indicating enhanced sensitivity of QD energy levels to gate voltages. The electrostatic potential simulations further support this observation by showing that stronger electrostatic confinement, which leads to smaller QD dimensions, reduces electron occupancy and improves the controllability of energy levels via gate tuning. These findings highlight the importance of precise <span>(alpha)</span> estimation for controlling QD energy levels, with implications for potential applications in QD-based qubit manipulations and charge sensing in scalable quantum devices.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"87 1","pages":"67 - 73"},"PeriodicalIF":0.9,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145143330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive analysis of the effect of optimal gate dielectric materials on stability, reliability, and electrical performance of a-Si:H thin-film transistor","authors":"Djemâa Ben Othmane,&nbsp;Nozha El Ahlem Doghmane,&nbsp;Abdellaziz Doghmane","doi":"10.1007/s40042-025-01383-w","DOIUrl":"10.1007/s40042-025-01383-w","url":null,"abstract":"<div><p>The development of Thin-Film Transistors (TFTs) for modern applications requires thicker gate dielectrics to improve scalability and efficiency. However, decreased thickness leads to higher leakage currents and reducing reliability. To address this challenge, the examination of other gate dielectric materials has been explored to select a dielectric material that is more suitable for this thin thickness. A numerical simulation was performed on the a-Si: H TFT structure using Silvaco Atlas software to study the impact of different gate dielectric materials with a wide band gap energy and a high dielectric constant (<b><i>k</i></b>) varying from 3.9 to 300 on device characteristics and electrical field distributions performance and to quantified this affect as mathematical expressions for several materials: SiO₂, Si₃N₄, Al₂O₃, Y₂O₃, Gd₂O₅, ZrO₂, CeO₂, La₂O₃, Ta₂O₅, HfO₂, TiO₂, Nb₂O₅, SrZrO₃, BaSrTiO₃, SrTiO₃. The obtained results showed that the increase in dielectric constant showed great improvement in the performance of the a-Si:H TFT, e.g., Drain current = 2.82 × 10^–5 A, capacitance per unit area = 2.65 × 10 ⁻⁹ F cm⁻², threshold voltage = 3.9 V, field-effect mobility = 0.0603 cm² V⁻¹ s ⁻¹, I_on/I_off ratio = 6.276 × 10⁷, and Subthreshold swing = 0.7691 V. These variations were quantified through curve fitting to establish mathematical expression for <b><i>k</i></b> as a function of every investigated parameter. Moreover, it was also shown that the use of high gate dielectric materials can effectively reduce leakage currents, ensuring improved reliability and performance in thicker TFTs and leading to a suitable choice for gate dielectric materials in modern applications.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"87 1","pages":"96 - 105"},"PeriodicalIF":0.9,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145143332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and numerical investigations on the operational characteristics of a hollow electrode plasma torch with an exit nozzle and reverse polarity discharge structure","authors":"Nam-Gi Lee,&nbsp;Dong-Hyun Lee,&nbsp;Sun-Woo Kim,&nbsp;Sang-Yun Baek,&nbsp;Jun-Ho Seo","doi":"10.1007/s40042-025-01386-7","DOIUrl":"10.1007/s40042-025-01386-7","url":null,"abstract":"<div><p>A plasma torch consisting of a rear hollow electrode, a cylindrical front electrode and a nozzle, all of which has a diameter of 10 mm, was designed and its operational characteristics in the electrical connection of reverse polarity were investigated experimentally and numerically. Assuming that the cathode spot is formed on the end part of the front and the arc plasma inside the torch is laminar flow, numerical analysis was carried out, which agreed well with the experimental results. For example, both results showed that the arc voltages and thermal efficiencies of the torch were increasing linearly when decreasing the arc current or increasing the flow rate of G1 gas, which is introduced between the rear and front electrodes. However, G2 gas injected between the front electrode and exit nozzle has little effect on the arc voltages and thermal efficiencies of the torch. This indicates that when the cathodic arc roots are anchoring on the end of the front electrode due to the electrical connection of reverse polarity, G2 gas primarily affects their axial movement into the nozzle section rather than arc length or temperature fields inside the electrodes, playing a role in stabilizing the plasma jet. As a result, the proposed plasma torch can produce a stable N₂ plasma jet with the thermal efficiency of the torch higher than 70% and the arc voltages higher than 250 V at the arc currents lower than 70 A and total gas flow rates of 50 L/min.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"86 12","pages":"1135 - 1147"},"PeriodicalIF":0.9,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145164941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic strength of pairing interaction in a two-band model high-temperature iron-based superconductor Ba1-yRy (Fe1−xTx)2As2 (R = Na and T = Co)","authors":"Teklie Lissanu Tegegne","doi":"10.1007/s40042-025-01372-z","DOIUrl":"10.1007/s40042-025-01372-z","url":null,"abstract":"<div><p>In this work, the theoretical study of magnetic strength of pairing interaction in two-band model high-temperature iron-based superconductors Ba(Fe_1−xCo_x)₂As₂ and Ba_1−xNa_xFe₂As₂ is conducted. With zero applied external magnetic field, the two-band model iron-based superconductors Ba(Fe_1−xCo_x)₂As₂ and Ba_1-xNa_xFe₂As₂ transition from the normal state to the superconducting state at a transition temperature of 22 K and 34 K, respectively. The theoretical study of critical magnetic fields, H_C2(T), Ginzburg–Landau coherence lengths, ζ_GL(T), Ginzburg–Landau penetration depths, and Ginzburg–Landau characteristic parameter for the iron-based superconductors Ba (Fe_1−xCo_x)₂As₂ and Ba_1-xNa_xFe₂As₂ from the two-band model has been conducted using the well-known phenomenological Ginzburg–Landau (GL) equation. In addition, the angular dependences of the critical magnetic field have been examined. The symmetry axis versus temperature, the angular dependence of the critical magnetic fields, H_C2 versus angle θ, the characteristic parameters, versus temperature, and the phase diagrams of the parallel and perpendicular critical magnetic fields, HC2 (T), the coherence lengths of GL, GL coherence lengths, ζ_GL (T), and the penetration depth of GL have been plotted by taking into account the available experimental values in the expressions obtained. The observations and my findings agree.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"86 12","pages":"1165 - 1175"},"PeriodicalIF":0.9,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}