A5100746306- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Atomic and Subatomic Physics Research
- Topological Materials and Phenomena
- Cosmology and Gravitation Theories
- Physics of Superconductivity and Magnetism
- Graphene research and applications
- 2D Materials and Applications
- Scientific Research and Discoveries
- Environmental Policies and Emissions
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Condensed Matter Physics
- Particle Detector Development and Performance
- Atmospheric chemistry and aerosols
- Vehicle emissions and performance
- Electronic and Structural Properties of Oxides
- Superconducting and THz Device Technology
- Quantum Information and Cryptography
- Complex Network Analysis Techniques
- Opinion Dynamics and Social Influence
- Tropical and Extratropical Cyclones Research
- Handwritten Text Recognition Techniques
- Air Traffic Management and Optimization
- Vehicle License Plate Recognition
- Thermal properties of materials
Pukyong National University
2025
Institute for Basic Science
2019-2024
Korea Advanced Institute of Science and Technology
2017-2023
Sogang University
2018-2022
Konkuk University Medical Center
2019
Korea National University of Transportation
2015
The Center for Axion and Precision Physics Research at the Institute Basic Science is searching axion dark matter using ultralow temperature microwave resonators. We report exclusion of mass range $10.7126--10.7186\text{ }\text{ }\ensuremath{\mu}\mathrm{eV}$ with near Kim-Shifman-Vainshtein-Zakharov (KSVZ) coupling sensitivity $10.16--11.37\text{ about 9 times larger 90% confidence level. This first search result in these ranges. It also a resonator physical less than 40 mK.
We report an axion dark matter search at Dine-Fischler-Srednicki-Zhitnitskii sensitivity with the CAPP-12TB haloscope, assuming axions contribute 100% of local density. The excluded axion-photon coupling g_{aγγ} down to about 6.2×10^{-16} GeV^{-1} over mass range between 4.51 and 4.59 μeV a 90% confidence level. achieved experimental can also exclude Kim-Shifman-Vainshtein-Zakharov that makes up just 13% haloscope will continue wide masses.
We report the results of an axion dark matter search over mass range 9.39-9.51 ${\mu}$eV. A flux-driven Josephson parametric amplifier (JPA) was added to cryogenic receiver chain. system noise temperature as low 200 mK achieved, which is lowest recorded among published cavity experiments with phase-insensitive JPA operation. In addition, we developed a two-stage scanning method boosted scan speed by 26%. As result, two-photon coupling in plausible model for QCD excluded order magnitude...
The axion, a hypothetical elementary pseudoscalar, is expected to solve the strong CP problem of QCD and also promising candidate for dark matter. most sensitive axion search experiments operate at millikelvin temperatures hence rely on instrumentation that carries signals from system cryogenic room temperature instrumentation. One biggest limiting factors affecting parameter scanning speed these detectors noise added by components in signal detection chain. Since first amplifier chain...
We report an extensive high-sensitivity search for axion dark matter above 1 GHz at the Center Axion and Precision Physics Research (CAPP). The cavity resonant search, exploiting coupling between axions photons, explored frequency (mass) range of 1.025 (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>4.24</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi mathvariant="normal">μ</a:mi><a:mi>eV</a:mi></a:mrow></a:math>) to 1.185 (<d:math...
Unmanned aerial vehicle (UAV) imaging provides the ability to obtain high-resolution images at a lower cost than satellite imagery and photography. However, multiple UAV need be mosaicked of large areas, resulting multispectral image mosaics typically contain seam lines. To address this problem, we applied irradiance, vignette, bidirectional reflectance distribution function (BRDF) filters performed field work using DJI Mavic 3 Multispectral (M3M) camera collect data. We installed calibrated...
The axion, a consequence of the PQ mechanism, has been considered as most elegant solution to strong-CP problem and compelling candidate for cold dark matter. Center Axion Precision Physics Research (CAPP) Institute Basic Science (IBS) was established on 16 October 2013 with main objective launch state art axion experiments in South Korea. Relying haloscope technique, our strategy is run several parallel explore wide range masses sensitivities better than QCD models. We utilize not only...
The haloscope is one of the most sensitive approaches to QCD axion physics within region where considered be a dark matter candidate. Current experimental sensitivities, which rely on lowest fundamental TM010 mode cylindrical cavity, are limited relatively low mass regions. Exploiting higher-order resonant modes would beneficial because it will enable us extend search range with no volume loss and higher quality factors. This approach has been discarded mainly significant degradation form...
We report an extensive high-sensitivity search for axion dark matter above 1\,GHz at the Center Axion and Precision Physics Research (CAPP). The cavity resonant search, exploiting coupling between axions photons, explored frequency (mass) range of 1.025\,GHz (4.24\,$\mu$eV) to 1.185\,GHz (4.91\,$\mu$eV). have introduced a number innovations in this field, demonstrating practical approach optimizing all relevant parameters haloscopes, extending presently available technology. CAPP 12\,T...
Fast economic growth and urbanization of China have been causing air pollution not only over its domestic but transboundary atmosphere. Recent high fine particle episodes in made the government move toward more stringent control policies - which are mostly fuel switching emissions control. In this research, we tried to understand characteristics Chinese their change by analyzing inventory year, sector, region. From inter-comparison existing bottom-up emission inventories, found relatively...
We report the first search for Sagittarius tidal stream of axion dark matter around $4.55\text{ }\text{ }\mathrm{\ensuremath{\mu}eV}$ using CAPP-12 TB haloscope data acquired in March 2022. Our result excluded Dine-Fischler-Srednicki-Zhitnitskii and Kim-Shifman-Vainshtein-Zakharov densities ${\ensuremath{\rho}}_{a}\ensuremath{\gtrsim}0.184$ $\ensuremath{\gtrsim}0.025\text{ }\mathrm{GeV}/{\mathrm{cm}}^{3}$, respectively, over a mass range from 4.51 to $4.59\text{ at 90% confidence level.
With the emergence of Dirac fermion physics in field condensed matter, magnetic quantum oscillations (MQOs) have been used to discern topology orbits materials. However, many previous researchers relied on single-orbit Lifshiftz-Kosevich formula, which overlooks significant effect degenerate MQOs. Since LK formula is valid for massless semimetals with small cyclotron masses, it imperative generalize method applicable a wide range semimetals, whether or massive. This report demonstrates how...
현재 국내 연구는 1차원 수치해석을 통한 침수방지대책의 효과분석 및 효율성을 입증하는 형태로 본 연구에서는 2차원 도시유출모형인 XP-SWMM 모형을 침수지역에 적용, 침수방지대책을 상호 비교 분석함으로써 수자원관리자의 효율적인 정책결정에 반영할 수 있도록 하는 것이 연구의 목적이다. 기상데이터는 지난 1967년부터 2011년까지 45년간 청주 기상대에서 수집한 것으로 통계 분석하여 사용하였다. 대상 배수구역 통수능력 분석을 50년 빈도 모의 결과 침수면적 <TEX>$539,548m^2$</TEX>, 최대침수심 1.0m, 침수시간 48분으로 분석되었다. 침수대책으로 A1 소배수구역의 증대를 위해 우회수로 지하저류시설 건설을 비교한 대상유역에 용량이 <TEX>$13,500m^3$</TEX>인 지하저류시설을 설치할 경우 빈도의 강우까지 침수가 완전 해소될 판단된다. 향후 침수 저감대책으로 이상기후에 대비할 있는 지하저류조 설치가 효율성이 좋을 Current domestic...
Electronic structures of rare-earth (R)-doped Bi2−xRxX3 (R=Ce,Gd; X=Se,Te) single crystals, which are promising candidates for magnetic topological insulators, have been investigated by employing soft X-ray absorption spectroscopy (XAS), circular dichroism (XMCD), and (CD) angle-resolved photoemission (ARPES). R M4,5 XAS XMCD measurements provide evidence that ions trivalent magnetic, confirming doped purely effects. ARPES Bi2−xCexSe3 show a finite energy gap x>0, arising from the broken...
Topological antiferromagnetic spintronics is an emerging field due to advantages such as no stray effect and high-speed dynamics. In bismuth chalcogenide topological insulators, the coexistence of long-range order topologically protected states has scarcely been observed. Here, order, which sets in direction magnetic moments perpendicular c axis, introduced by Eu substitution Bi2Se3, therefore it influences electronic properties Bi2Se3. Despite substitution, Shubnikov–de Haas (SdH)...
We applied an effective approximation into Maxwell's equations with axion interaction for haloscope searches. A set of acquired from this describes just the reacted fields generated by anomalous interaction. Unlike other approaches, inherently satisfies boundary conditions The electromagnetic field solutions were evaluated both cylindrical and toroidal cavity geometries including when mass becomes ultra-light (sub-meV). small but non-zero difference between electric magnetic stored energies...
We report an axion dark matter search at Dine-Fischler-Srednicki-Zhitnitskii sensitivity with the CAPP-12TB haloscope, assuming axions contribute 100\% of local density. The excluded axion--photon coupling $g_{aγγ}$ down to about $6.2\times10^{-16}$ GeV$^{-1}$ over mass range between 4.51 and 4.59 $μ$eV a 90\% confidence level. achieved experimental can also exclude Kim-Shifman-Vainshtein-Zakharov that makes up just 13\% haloscope will continue wide masses.
Photoexcited carriers in three-dimensional topological insulators (3D TIs) decay rapidly through the electron-electron and electron-phonon scattering. While most studies focus on such fast dynamics, recent experiments find slow photovoltage (PV) dynamics arising from band-bending potentials, which optical transitions two-dimensional electron gas (2DEG) are effective. Although early investigations speculated existence of multiple structures TI surface to bulk, how PV 2DEG correlated presence...
We study multi-component dark matter scenarios and the Galactic 511 keV $\gamma$-ray emission line signal in framework of a local, $U(1)_D$ extension Standard Model. A light vector particle associated with may decay annihilate to electron-positron pairs. The produced positrons turn form positroniums that subsequently two photons, accounting for observed emission. Three are investigated. First, we consider minimal where gauge boson Higgs newly introduced content. As second scenario, WIMP-type...
The electronic structures of the magnetic topological insulator candidates Ce-substituted Bi2–xCexSe3 (x ≤ 0.12) have been investigated through angle-resolved photoemission spectroscopy (ARPES), soft X-ray absorption (XAS), and circular dichroism (XMCD) measurements on high-quality single crystals. Ce 3d XAS XMCD provide evidence that substituted ions in are trivalent magnetic, confirming purely effect Ce-substitution. ARPES reveal formation an energy gap (Δ) for x &gt; 0, indicating...
We report the results of an axion dark matter search over mass range 9.39-9.51 $μ$eV. A flux-driven Josephson parametric amplifier (JPA) was added to cryogenic receiver chain. system noise temperature as low 200 mK achieved, which is lowest recorded among published cavity experiments with phase-insensitive JPA operation. In addition, we developed a two-stage scanning method boosted scan speed by 26%. As result, two-photon coupling in plausible model for QCD excluded order magnitude higher...