Journal of the Korean Physical Society最新文献

{"title":"Test of full-performance operation (80 MW, 4 (upmu )s, 60 Hz) of the latest S-band klystron at PAL","authors":"S. J. Park,&nbsp;C. K. Min,&nbsp;Y. G. Park,&nbsp;S. D. Jang,&nbsp;G. Y. Jang,&nbsp;H. S. Shin","doi":"10.1007/s40042-026-01603-x","DOIUrl":"10.1007/s40042-026-01603-x","url":null,"abstract":"<div><p>We report high-voltage (HV) and RF processing results of the latest domestically manufactured S-band pulse klystrons developed for the Pohang Accelerator Laboratory (PAL). Previous prototypes of the 80 MW-class tube suffered from frequent gun arcing at 60 Hz repetition rate, which limited routine operation to 30 Hz. Earlier studies identified clump-assisted breakdown in the diode region and electron multiplication at the ceramic triple point as the dominant mechanisms, and proposed mitigation via improved electrode surface preparation and a triple-point electrostatic shield. These measures were incorporated into the latest units (serial numbers VK4 and VK5), which were fabricated in 2024 and conditioned in the PAL klystron and modulator test laboratory. VK4 reached 80 MW peak RF output with a 4 <span>(upmu )</span>s pulse width at 60 Hz repetition rate and exhibited stable operation. From detailed analysis of HV and RF processing data, we show that enhanced electrode polishing reduces the total HV arc rate by <span>(approx 60%)</span> and that slow breakdown events are eliminated by the triple-point shield so that only fast arcs remain. We further observe that RF breakdowns depend sensitively on the TiN coating of the output window, with an excessively thick coating leading to increased RF arc activity, likely by ohmic heating. The successful demonstration of 80-MW, 4-<span>(upmu )</span>s, 60-Hz operation with a domestically produced tube validates the maturity of the klystron design and supports readiness for series production and routine accelerator service.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 on","pages":"272 - 281"},"PeriodicalIF":1.0,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148459044","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":"Strain-induced symmetry transition and non-Fermi liquid behavior in CaRuO3 thin films","authors":"Sang-A Lee,&nbsp;Jae-Yeol Hwang","doi":"10.1007/s40042-026-01616-6","DOIUrl":"10.1007/s40042-026-01616-6","url":null,"abstract":"<div><p>We report the experimental verification of a strain-induced symmetry change associated with octahedral geometry in epitaxial CaRuO₃ thin films, where the decoupling of octahedral rotation modes dictates both macroscopic elastic and quantum transport properties. High-resolution X-ray diffraction reveals that a 1.43% epitaxial tensile strain from SrTiO₃ (0 0 1) substrates triggers a structural transition from the bulk orthorhombic (<i>Pbnm</i>) to a tetragonal (<i>P</i>4/<i>mbm</i>) phase. This symmetry transition induces a <i>a</i>⁰<i>a</i>⁰<i>c</i>⁺ rotation angle crossover characterized by the linearization of apical Ru–O–Ru bond angles to 180<b>°</b>, and a simultaneous equatorial buckling to 137.5<b>°</b>. Such RuO₆ reconfiguration leads to significant mechanical hardening along the apical axis, manifested by an anomalous effective Poisson ratio (ν_eff) of 0.13. Furthermore, the anisotropic octahedral distortion, driven by the equatorial buckling and bond elongation (2.095 Å), enhanced electronic correlations, thereby increasing the effective mass and stabilizing a non-Fermi liquid state with a linear temperature dependence of resistivity. By quantifying these structural reconfigurations and their subsequent impact on elastic and electronic functionalities, our findings provide a robust framework for the rational design of ruthenate-based oxide electronics.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"88 12","pages":"1347 - 1354"},"PeriodicalIF":0.9,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148193807","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":"Design of a proton beamline specialized for radiation testing of semiconductors at KOMAC","authors":"Han-Sung Kim,&nbsp;Seung-Hyun Lee,&nbsp;Sang-Pil Yun,&nbsp;Dong-Hwan Kim,&nbsp;Hyeok-Jung Kwon","doi":"10.1007/s40042-026-01618-4","DOIUrl":"10.1007/s40042-026-01618-4","url":null,"abstract":"<div><p>The demand for radiation hardness testing of semiconductor devices has been rapidly increasing, particularly for space and high-reliability applications. To address this need, a dedicated proton beamline for semiconductor radiation testing is being developed at the Korea Multipurpose Accelerator Complex (KOMAC) using an existing 100 MeV proton accelerator. The beamline is designed to deliver a large-area, low-flux proton beam suitable for displacement damage and single event effect tests. The beamline incorporates a graphite-based water-cooled collimator to reduce the beam intensity and a magnet optics system consisting of quadrupole and octupole magnets to generate a wide and uniform flat-top beam profile. Beam dynamics simulations were performed to evaluate different optics configurations under the geometrical constraints of the penetration pipe. The simulation results demonstrate that a beam size of 100 mm × 100 mm with a uniformity better than ± 10% can be achieved. The collimator was designed to withstand an average beam power of up to 800 W, and coupled thermal–structural analyses confirmed that both temperature rise and thermal stresses remain within safe limits. Radiation shielding analyses further verified that the resulting dose rates satisfy radiation safety requirements. In addition, two octupole electromagnets were designed, fabricated, and experimentally characterized, showing good agreement between measured and simulated magnetic field properties. A dedicated target room was also designed to support efficient semiconductor irradiation experiments, featuring real-time beam diagnostics, redundant beam on-off control, and an integrated control interface with the accelerator system. The proposed beamline is expected to significantly enhance proton irradiation capabilities at KOMAC and provide an effective testing platform for the semiconductor industry and related research fields.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 on","pages":"282 - 291"},"PeriodicalIF":1.0,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148459045","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":"Erratum: Enhanced thermoelectric performance of Zn-doped bornite Cu5Fe1−xZnxS4","authors":"Hyeokmin Kwon,&nbsp;Il-Ho Kim","doi":"10.1007/s40042-026-01611-x","DOIUrl":"10.1007/s40042-026-01611-x","url":null,"abstract":"","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"88 11","pages":"1271 - 1271"},"PeriodicalIF":0.9,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147968090","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":"Operation status of KOMAC Linac","authors":"Hyeok-Jung Kwon,&nbsp;Han-Sung Kim,&nbsp;Young-Gi Song,&nbsp;Sang-Pil Yun,&nbsp;Kyung-Hyun Kim,&nbsp;Hae-Seong Jeong,&nbsp;Seunghyun Lee","doi":"10.1007/s40042-026-01608-6","DOIUrl":"10.1007/s40042-026-01608-6","url":null,"abstract":"<div><p>A 100-MeV proton linear accelerator (linac) which has been operating since 2013 at Korea Multi-purpose Accelerator Complex (KOMAC) started 24-h beam service in 2024 and neutron beam service in 2025. In addition to the operation for user beam service, it is planned to upgrade the existing 100-MeV accelerator according to the needs of the user community. In this paper, the operation status of KOMAC proton linac is presented and the upgrade plan is summarized.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 on","pages":"258 - 271"},"PeriodicalIF":1.0,"publicationDate":"2026-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148459022","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":"Silver nanoparticles (AgNPs) as broad-spectrum antimicrobial agents: synthesis, mechanisms of action, and applications","authors":"Mümin Mehmet Koç,&nbsp;Özge Özcan,&nbsp;Sevilay İnal Kabala","doi":"10.1007/s40042-026-01606-8","DOIUrl":"10.1007/s40042-026-01606-8","url":null,"abstract":"<div><p>Silver nanostructures have awakened considerable interest due to their extensive antimicrobial capabilities, including antibacterial, antiviral, and antifungal uses. This review highlights the influence of production techniques on the dimensions, shape, and multimodal functionalities of these nanoparticles. Essential production processes, including chemical reduction, green synthesis, and physical procedures, which provide meticulous control over the properties of nanostructures, were also assessed. Chemical approaches, including reduction processes, ensure scalability and consistency, whereas green synthesis presents an environmentally sustainable option by utilizing plant extracts and microorganisms to generate biocompatible nanoparticles. Silver nanostructures demonstrate significant antibacterial efficacy via mechanisms including enzyme inhibition, cell wall disintegration, and DNA damage, successfully addressing drug-resistant bacterial pathogens. Likewise, their antifungal characteristics specifically target fungal biofilms and disrupt membrane integrity, demonstrating potential efficacy against various strains. Moreover, silver nanostructures exhibit antiviral properties by interfering with protein synthesis, disrupting viral replication, and preventing the entry of viruses into host cells, thereby demonstrating efficacy against many viral infections. The multimodal properties of silver nanostructures, encompassing both antibacterial and antioxidant actions, augment their utility in medical and industrial sectors. Notwithstanding these benefits, cytotoxicity continues to be a significant issue, requiring sophisticated synthesis methods to enhance safety and efficacy. This thorough analysis emphasizes silver nanostructures as essential instruments in combating microbial resistance, highlighting their potential in novel therapeutic applications. In contrast to traditional studies, this research addresses the antibacterial properties of silver nanoparticles connected to the production process. However, in order to maximize the potential of the nanoparticles and support future research, potential limitations and disadvantages were also explored.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"88 12","pages":"1273 - 1311"},"PeriodicalIF":0.9,"publicationDate":"2026-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148193823","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":"Pseudo-Landau levels on a strain crystal","authors":"SungMin Kim,&nbsp;Sungjong Woo,&nbsp;Nojoon Myoung,&nbsp;Hee Chul Park","doi":"10.1007/s40042-026-01600-0","DOIUrl":"10.1007/s40042-026-01600-0","url":null,"abstract":"<div><p>We investigate the electronic properties of a graphene nanobubble superlattice realized as a periodic array of Gaussian-shaped deformations. The periodic strain induces modification of band structures leading to the emergence of new features. In particular, the density of states (DOS) exhibits a series of sharp peaks as a function of the bubble size, while the overall DOS profile remains nearly constant. These peaks are interpreted as signatures of pseudo-Landau levels (pLLs) formed under the influence of the strain-induced pseudomagnetic field (PMF). Furthermore, resonant peaks in conductance are observed near the DOS maxima, and the corresponding current densities are found to be spatially localized around the nanobubbles. These results collectively support the interpretation that the DOS peaks originate from discrete pLLs generated by the periodic pseudomagnetic field in the strained graphene lattice.\u0000</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"88 12","pages":"1340 - 1346"},"PeriodicalIF":0.9,"publicationDate":"2026-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148193824","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":"Modulated nonlinear dynamics and mode-locking in silent Hodgkin–Huxley neurons exposed to extremely low-frequency electric field","authors":"Mahdi Gholampour,&nbsp;Esmaeil Mahdavi,&nbsp;Majid Amirzadeh","doi":"10.1007/s40042-026-01597-6","DOIUrl":"10.1007/s40042-026-01597-6","url":null,"abstract":"<div><p>Neurons, being electrically excitable cells, are highly susceptible to external electric fields. Motivated by previous studies on silent Hodgkin–Huxley neurons under zero external current, we numerically investigate how an extremely low-frequency external electric field influences the dynamics of a silent Hodgkin–Huxley neuron under varying levels of external (injected) DC current. Our results show that, in addition to previously reported subthreshold oscillations, <span>(p!:!q)</span> mode-locking (where <i>p</i> spikes occur per <i>q</i> cycles of stimulation), and chaotic behaviors at zero external current, increasing the external current gives rise to additional dynamical regimes, including quasi-periodic oscillations and shifts in the location of the maximum firing rate as the current approaches the critical value <span>(I_{textrm{ext}} approx 9.7~mathrm {mu A/cm^2})</span>. The emergence of these behaviors depends on the external electric field parameters and the level of external current. Analysis of the largest Lyapunov exponent revealed that chaotic states arise near the threshold amplitude in the absence of external current, whereas such states are rarely observed at larger amplitudes <span>(V_0 &gt; 7~textrm{mV})</span>. These findings extend earlier studies by highlighting the crucial role of external current in shaping the nonlinear dynamical responses of silent Hodgkin–Huxley neurons to extremely low-frequency electric fields.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"88 12","pages":"1360 - 1372"},"PeriodicalIF":0.9,"publicationDate":"2026-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148193822","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":"Noise-resilient quantum metrology using entangled multi-qubit states: robustness analysis and measurement strategies","authors":"Esraa Mishref,&nbsp;Ahmed El-Tawargy,&nbsp;Wael Ramadan,&nbsp;Mohamed Nawareg","doi":"10.1007/s40042-026-01577-w","DOIUrl":"10.1007/s40042-026-01577-w","url":null,"abstract":"<div><p>We investigate the robustness of quantum-metrological usefulness for a class of highly entangled multi-qubit states, extending the framework introduced in the previous work. Our analysis focuses on the impact of two prototypical noise models, white and colored noise, on various quantum states, including GHZ, W, Dicke with multiple excitations, cluster, and ring cluster states, as well as a newly studied <span>(vert {psi _5} rangle)</span> state. The robustness is quantified via a global optimization of quantum Fisher information over arbitrary local operators. We analyze the effect of increasing qubit number and examine different local measurement strategies, comparing uniform versus individually optimized local operators. Results reveal state-dependent behavior: while states like <span>(vert {GHZ_N} rangle)</span> and <span>(vert {W_N} rangle)</span> exhibit increasing robustness under colored noise and decreasing robustness under white noise, the <span>(vert {psi _5} rangle)</span> state shows improvement under both types. These findings provide new insights into designing metrologically useful states resilient to practical noise conditions.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"88 12","pages":"1312 - 1324"},"PeriodicalIF":0.9,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148193874","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":"Evidence for strong electronic correlations in the bulk state of grey arsenic","authors":"Minhee Kang,&nbsp;Hayoon Im,&nbsp;Ji-Eun Lee,&nbsp;Sung-Kwan Mo,&nbsp;Jonathan Denlinger,&nbsp;Kyoo Kim,&nbsp;Pavel Dudin,&nbsp;Jose Ávila,&nbsp;Haeyong Kang,&nbsp;Jaekwang Lee,&nbsp;Jong Mok Ok,&nbsp;Xuetao Zhu,&nbsp;Jiandong Guo,&nbsp;Choongyu Hwang","doi":"10.1007/s40042-026-01593-w","DOIUrl":"10.1007/s40042-026-01593-w","url":null,"abstract":"<div><p>We investigate the electron band structure of grey arsenic, whose (111) face hosts the topological Shockley state. Interestingly, the bulk band close to the touching point with the surface state exhibits the characteristics of inelastic scattering. Moreover, the band structure analysis reveals linearity in the imaginary part of electron self-energy. These features are analogous to those observed in high-temperature superconductors and marginal Fermi liquid systems, respectively, where strong electronic correlations exist. Our results suggest that correlated many-body states can be connected by non-interacting topological states, providing a viable playground to explore the coupling between topological and correlated states via grey arsenic surface.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"88 12","pages":"1335 - 1339"},"PeriodicalIF":0.9,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148193875","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}