A5102817031- Dark Matter and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Cosmology and Gravitation Theories
- Vacuum and Plasma Arcs
- HVDC Systems and Fault Protection
- Particle physics theoretical and experimental studies
- Electrical Fault Detection and Protection
- Engineering Applied Research
- Geotechnical Engineering and Analysis
- Geotechnical Engineering and Underground Structures
- High-Voltage Power Transmission Systems
- Thermal Analysis in Power Transmission
- Quantum, superfluid, helium dynamics
- High voltage insulation and dielectric phenomena
- Nuclear Physics and Applications
- Smart Grid and Power Systems
- Civil and Geotechnical Engineering Research
- Concrete and Cement Materials Research
- Grouting, Rheology, and Soil Mechanics
- Corrosion Behavior and Inhibition
- Computational Physics and Python Applications
- Tunneling and Rock Mechanics
- Non-Destructive Testing Techniques
- Electrical Contact Performance and Analysis
- Power Line Inspection Robots
Institute for Basic Science
2019-2024
Korea Advanced Institute of Science and Technology
2009-2022
LSIS (South Korea)
2012-2019
Korea Electrotechnology Research Institute
2019
Korea Testing & Research Institute
2015
Jeonju University
2012-2013
Korea Gas Corporation (South Korea)
2006-2013
Korea Fisheries Resources Agency
2012
Samsung (South Korea)
2009
Pusan National University
2008
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.
The axion has emerged as the most attractive solution to two fundamental questions in modern physics related charge-parity invariance strong interactions and invisible matter component of our Universe. Over past decade, there have been many theoretical efforts constrain mass based on various cosmological assumptions. Interestingly, different approaches from independent groups produce good overlap between 20 30 μeV. We performed an experimental search probe presence dark axions within this...
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...
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...
Nambu-Goldstone bosons, or axions, may be ubiquitous. Some of the axions have small masses and thus serve as mediators long-range forces. In this paper, we study force mediated by an extremely light axion, $\phi$, between visible sector dark sector, where matter lives. Since nature does not preserve CP symmetry, coupling $\phi$ is generically CP-violating. case, induced behaves effective magnetic field. If acts on electrons nucleons, spins them Earth precess around a fixed direction towards...
A 22.9 kV/630 A-class superconducting fault current limiter (SFCL) was installed on a distribution line in Icheon Substation for real-grid operation. The substation is located semi-urban area with moderate loads. SFCL of hybrid type. After installation it subjected to series on-site tests. Test procedures were determined by following convention testing both superconductivity-related and not-related specifications the SFCL. Tests performed minimum limiting test, temperature dielectric...
The cavity haloscope has been employed to detect microwave photons resonantly converted from invisible cosmic axions under a strong magnetic field. In this scheme, the axion-photon conversion power formulated be valid for certain conditions, either Q ≪ axion or ≫ . This remedy, however, fails when these two quantities are comparable each other. Furthermore, noise flow treated independently of impedance mismatch system, which could give rise misleading estimates experimental sensitivity. We...
In electrical power systems, especially highly networked and become smart grid recently, faster protection relay circuit breaker are more desirable for system stability at short accidents. Nowadays general interruption time of is 3~5 cycle trip signal sending a about 2 instant operation. Most cases these sufficient the systems but some special required. We proposed prototype AC high speed which could interrupt current 12.5kA, 25.8kV within 1 60Hz. Also we developed over relay(OCR) can send...
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...
Because of nature the DC power distribution system, such as existence electronic converters with link capacitors and low system inductance, it has been known that protection against short circuit fault would be difficult compared to AC system. The solid state breaker (SSCB) is one candidates for solution thanks its faster response higher controllability reusability mechanical or fuse. However, without proper overvoltage suppressing circuit, due inductance collapse semiconductor switches in...
A 25.8 kV / 630 hybrid superconducting fault current limiter (SFCL) has successfully designed, tested and finally installed in a real power grid at Icheon substation for the purpose of pre-commercial demonstrations. The SFCL is composed high temperature superconductor (HTS), fast switch (FS), limiting reactor (CLR) module. In this SFCL, HTS module plays role sensing letting direction an electric turn to FS path. reduction amplitude done by CLR combination made conventional electrical...
This paper focuses on the design of a snubber circuit for Solid State Circuit Breaker (SSCB) based SiC MOSFET. It analyzes operation principle and pros cons existing circuit. Based analysis, novel bidirectional suppressing fault current quickly simultaneously protecting overvoltage MOSFET is proposed. The proposed discussed, criteria are addressed case that source inductance load SSCB asymmetrical. Through computer simulation results, it shown effective in keeping voltage across MOSFETs...
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.
ABSTRACTS The purpose of this paper is to evaluate the characteristics possible cracks induced on tunnel lining according magnitude and shape applied loads. For a study mechanical behavior cracking lining, down scaled models were tested in consideration loading type, side confinement, double opening behind concrete so. Total twenty-four specimens including single prepared with mortar mixes. was discussed based load, failure critical section finally load-deflection curve. A dimensionless...
A new risk analysis system for estimating the factors in tunneling is suggested consideration of complex effect tunnel construction. It verified that various can be expressed by stability and environment index using numerical statistical analysis. Stability includes safety ground condition, amount settlement, condition inflow earthquake as a variable, vibration noise blasting under construction train operation. The geotechnical were performed classifying factor calculated SSR method, damage...
Air Circuit Breaker (ACB) is an electric control device that can interrupt the abnormal current in low voltage (less than 1,000Vac or 1,500Vdc) distribution line. In general, means short-circuit, over-load and grounding causes serious damage on devices system. Therefore, circuit breaker shall break a fault quickly safely to prevent accidents Nowadays, DC gains much attentions world because it protect photovoltaic (PV) facilities, energy storage system (ESS). particular, breakers (or...