A5044651915- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Gyrotron and Vacuum Electronics Research
- Pulsed Power Technology Applications
- Laser Design and Applications
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Electromagnetic Launch and Propulsion Technology
- Embedded Systems and FPGA Design
- Particle Detector Development and Performance
- Advanced X-ray Imaging Techniques
- Advanced Battery Technologies Research
- Electrostatic Discharge in Electronics
- Vacuum and Plasma Arcs
- Technology and Data Analysis
- Electric and Hybrid Vehicle Technologies
- Corneal Surgery and Treatments
- Advanced Condensed Matter Physics
- Laser-induced spectroscopy and plasma
- Laser-Plasma Interactions and Diagnostics
- Acoustic Wave Phenomena Research
- Cryptographic Implementations and Security
- Demographic Trends and Gender Preferences
- Microgrid Control and Optimization
- Noise Effects and Management
Pohang University of Science and Technology
2000-2023
Massachusetts Institute of Technology
2023
Hyundai Heavy Industries (South Korea)
2020
Samsung Medical Center
2016
Sungkyunkwan University
2016
Pennsylvania State University
2016
Pohang Accelerator Laboratory
2000-2014
Pohang TechnoPark (South Korea)
2002-2012
Wright State University
1990
Wright-Patterson Air Force Base
1990
The fabrication of Micro-Perforated Panels (MPPs) still constitutes a challenge to the acoustic materials industry because it usually requires expensive manufacturing techniques obtain holes submillimetre size. In this context, rise additive or 3D printing (3DP) technologies over last years has paved way for design and development new at microscopic scale. Among these, Digital Light Processing (DLP) technology emerges as an excellent option due its advantages in terms speed higher accuracy...
This article proposes a new strategy for integrating type of distributed generation (DG) into shipboard microgrid (MG). The study focuses on the application shaft generator (SG) system, which is first inverter-based DG installed in most large-sized ships. squirrel-cage induction commonly used SG system examined control stability, and an adaptive observer proposed to estimate stator resistance SG. includes virtual impedance inner loop grid-forming converter smooth integration MG, adopting...
Radial multichannel pseudospark switches for extremely high-charge transfer were designed, constructed, and tested. The characteristics of the measured different electrode geometries materials in hydrogen helium as function gas pressure. operated a 100 kJ capacitor bank conducted an effective charge up to 31 C. A sealed-off radial switch was also manufactured tested with 300 bank. successfully 105 kA peak current 78 C transfer. experimental results demonstrated that SiC electrodes triggered...
Cylindrical type air core pulse transformers capable of passing high voltage and energy waveforms with efficiency low distortion require a much more delicate design balance physical dimensions electrical parameters than iron or ferrite units. The structure an transformer is relatively simple, but considerable attention needed to prevent breakdown between windings. Since the thickness windings in spiral on order sub-millimeter, field enhancement at edge very high. It is, therefore, important...
The dislocations and twins in superconducting Bi-Ca-Sr-Cu-O samples are examined by scanning electron microscopy transmission microscopy. results indicate that these defects inherent to the materials. grains large size (1--10 \ensuremath{\mu}m), but they frequently divided into subgrains low-angle grain boundaries. Furthermore, evidence is found for discommensurate walls associated with incommensuration along b axis.
Multigap pseudospark devices can be used to produce intense pulsed electron beams. Pseudospark discharge is generally initiated by self-breakdown or an external trigger in which DC high voltage used. In this work, we investigated a pulse charge mode generate enhanced beam from 10-gap device. the mode, applied Using could obtain beams wider ranges of and pressure than self-discharge mode. We achived maximum efficiency at 3×10-1 mbar Ar gas. Under best condition, also observed well-focused...
Total 144 quadrupole magnets are installed in the PLS. The connected series with groups of two or 24. Each group is powered by a high-precision constant-current DC power supply. For purpose beam based alignment position monitors PLS, it necessary to adjust current each independently. To achieve this, high shunt regulator designed. It can maximum 50 A magnet current. programmable and amplitude be varied linearly 12-bit resolution. Power transistors used regulator. operation linear region....
The 2-GeV electron linac at Pohang accelerator laboratory (PAL) has been operated continuously as a full energy injector for the Light Source (PLS) since Dec. 1994. There have continuous efforts to improve klystron-modulator (K&M) system make it more stable and reliable. To self-diagnostic, operation, monitoring, remote communication, we developed new modulator controller based on an industrial PC platform. mainly consisted of interlock signal conditioning module, fast pulse...
A high power blue-green laser has been pumped with an array of multiple-stage hypocycloidal-pinch plasmas. The maximum untuned obtained LD-490 dye exceeded 230 kW a pulse width 1.0 μs (FWHM). characteristics the new pumping source and optical coupling configuration indicate that system can be developed for repetitive average operation.
Pohang Accelerator Laboratory (PAL) is constructing the 2-GeV Light Source (PLS). The electron linear accelerator will be used as a full energy injector to storage ring. There are 42 accelerating columns in 150-m long linac. linac powered by 11 klystrons of 80-MW maximum output power, which driven 200-MW modulators. Two modulators connected already under normal operation, and assembly work for nine remaining progress. In tunnel, about half has been installed. cooling system completed along...
We had designed, fabricated, and tested sealed-off triggered vacuum switches (TVSs) to use as an ETC-gun switch. To fabricate the TVS, we developed fabrication processes such part machining, chemical cleaning, ceramic metal brazing, welding, baking, getter processing test procedures. The fabricated were with capacitor banks of 100 kJ 300 kJ. prototype successfully up 30 kV peak charging voltage, kA current, 1.2 ms pulsewidth, 74-coulomb integrated charge transfer. It also showed good trigger...
Complete design, assembly, and testing of 200 MW modulators are in progress at the Pohang Accelerator Laboratory (PAL) for full energy injection linac system Light Source (PLS). A 150 pre-prototype modulator (350 kV, 3.5 /spl mu/s flat-top width, 840 Omega/ load) has been assembled tested up to 175 MW. Design, construction, test a prototype (400 4.4 800 also completed. Eleven units main under their assembly is expected be completed 1993. This paper presents design current status performance...
This paper presents a design concept to overview the feasibility of utilizing modern energy storage systems as substitution conventional machinery auxiliaries, which are necessarily installed support internal combustion engines' operation. For example, common compressed air system required for engine starting and emergency stopping occupies substantial space in ship. Owing increased capacity reduced price batteries nowadays, electric motors solenoid valves can supersede system, we save...
A total of 12 units high power klystron-modulator systems are under continuous operation in the Pohang Light Source (PLS) linac. The peak powers modulator and klystron 200 MW 80 MW, respectively. output frequency is 2856 MHz. Each compressed with an SLED supplied to four three-meter long accelerating columns. Final electron energy PLS linac 2 GeV. has been operated as a full injector for since December 1994. Annual hour system about 5000 hours. Since commissioning linac, voltage run time...
From 2011, the Pohang Accelerator Laboratory (PAL) had started 10 GeV PAL-XFEL project. The needs a highly stable electron beam. very beam voltage of klystron- modulator is essential to provide acceleration field for an beam[1]. Thus, system XFEL requires less than 50 ppm PFN stability. To get this high stability on system, inverter type HVPS pivot component. requested specification power supply being developed kV, 5 kJ/sec 1 sets and 30 4 at PAL. In paper, we will discuss development test...