• Nuclear Engineering and Technology
• /
• v.55 no.7
• /
• pp.2438-2446
• /
• 2023

To cool down a nuclear reactor core and prevent the fuel damage without a pump-driven active component during any anticipated accident, the passive emergency core cooling system (PECCS) was designed and adopted in an advanced light water reactor, i-POWER. In this study, for a validation of the cooling capability of PECCS, thermal-hydraulic integral effect tests were performed with the ATLAS facility by simulating intermediate and small break loss-of-coolant accidents (IBLOCA and SBLOCA). The test result showed that PECCS could effectively depressurize the reactor coolant system by supplying the safety injection water from the safety injection tanks (SITs). The result pointed out that the safety injection from IRWST should have been activated earlier to inhibit the excessive core heat-up. The sequence of the PECCS injection and the major thermal hydraulic transient during the SBLOCA transient was similar to the result of the IBLOCA test with the equivalent PECCS condition. The test data can be used to evaluate the capability of thermal hydraulic safety analysis codes in predicting IBLOCA and SBLOCA transients under an operation of passive safety system.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2020.06a
• /
• pp.120-120
• /
• 2020

Based on the simple sequence repeat (SSR) marker, a Korean wheat core collection were established with 616 wheat accessions. Among them, the SNP genotyping for the entire genome was performed using DNA chip array to clarify the whole genome SNP profiles. Consequently, a total of 35,143 SNPs were found and we re-established a mini-core collection with 247 accessions. Population diversity and phylogenetic analysis revealed genetic diversity and relationships from the mini core set. In addition, genome-wide association study (GWAS) was performed on 19 phenotypic traits; ear type, awn length, culm length, ear length, awn color, seed coat color, culm color, ear color, loading, leaf length, leaf width, seeding stand, cold damage, weight, auricle, plant type, heading stage, maturation period, upright habit, and degree of flag leaf. The GWAS was performed using the fixed and random model circulating probability unification (FarmCPU), which identified 14 to 258 SNP loci related to 19 phenotypic traits. Our study indicates that this Korean wheat mini-core collection is a set of germplasm useful for basic and applied research with the aim of understanding and exploiting the genetic diversity of Korean wheat varieties.

• 한국생물공학회:학술대회논문집
• /
• 2003.10a
• /
• pp.582-585
• /
• 2003

Sequence analysis indicated that Bacillus polymyxa MGL21 CFTase was divided into five distinct regions. CFTase contained three regions of repeat sequences at the N-terminus and C-terminus. The endo-inulinase region of homology (ERH) of CFTase was similar to that of Pseudomonas mucidolens endo-inulinase. Furthemore, CFTase possessed a highly conserved core region. In order to understand the role of the core region on the function of CFTase from B. polymyxa MGL21 CFTase ${\Delta}NC$ was prepared. The molecular weight of the purified wild type CFTase and $CFTase{\Delta}NC$ were 148kDa, 90kDa, respectively.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2001.10a
• /
• pp.183-186
• /
• 2001

In this paper, the analytical model to understand the propagation of electromagnetic waves in the foam core sandwich structures was proposed. Using the analytical model, efforts were made to find the optimal stacking sequence of composite skins for maximum transmittance of electromagnetic wave. Numerical analyses of unidirectional composites and foam as a function of incident angle were performed. From the results of analysis, the general tendencies of transmittance of electromagnetic wave through composites and foam were obtained. Based on the general tendencies, optimal stacking sequences of composite skins for the maximum transmittance of electromagnetic wave were found with certain ranges of incident angle using genetic algorithm(GA).

• Genomics & Informatics
• /
• v.11 no.1
• /
• pp.38-45
• /
• 2013

In cancer genome studies, the annotation of newly detected oncogene/tumor suppressor gene candidates is a challenging process. We propose using concept lattice analysis for the annotation and interpretation of genes having candidate somatic mutations in whole-exome sequencing in acute myeloid leukemia (AML). We selected 45 highly mutated genes with whole-exome sequencing in 10 normal matched samples of the AML-M2 subtype. To evaluate these genes, we performed concept lattice analysis and annotated these genes with existing knowledge databases.

• Publications of The Korean Astronomical Society
• /
• v.25 no.3
• /
• pp.59-64
• /
• 2010

The core and global properties of the early-type ("red sequence") galaxies in the Virgo and Fornax clusters are examined using high-quality HST/ACS imaging for 143 galaxies. Rather than dividing neatly into disparate populations having distinct formation and/or evolution histories, many of the core and global properties of these galaxies show smooth and systematic variations along the galaxy luminosity function. The few examples of the rare class of compact elliptical galaxies in our sample all show properties that are strongly suggestive of tidal stripping by massive galaxies; if so, then these systems should not be viewed as populating the low-luminosity extension of so-called "normal" elliptical sequences. These results demonstrate that complete and/or unbiased samples are a pre-requisite for identifying the physical mechanisms that gave rise to the early-type galaxies we observe locally, and how these mechanisms varied with mass and environment.

• Proceedings of the Microbiological Society of Korea Conference
• /
• 2002.10a
• /
• pp.159-161
• /
• 2002

Bacteriophage lambda integrase carries out the site-specific recombination of lambda. Integrase contains two DNA binding domains with distinct sequence specificity, namely arm-type binding and core-type binding domains. The amino-terminal arm-binding domain is structurally related to the three-stranded $\beta-sheet$ family of DNA-binding domains. Integrase binding to the high affinity arm-type site by the amino-terminal domain facilitates Int binding to the low affinity core-type site, where the cleavage and strand exchange occurs. The amino-terminal domain of Int also modulates the core-binding and catalysis through intramolecular domain-domain interaction and/or intermolecular interactions between Int monomers. In addition, the amino-terminal domain interacts cooperatively with excisionase during excision. This indicates that amino-terminal domain of Int plays an important role in formation of proper higher-order nucleoprotein structure required for lambda site-specific recombination.

• Carbon letters
• /
• v.15 no.2
• /
• pp.125-128
• /
• 2014

In this study, the effect of stacking sequence on the flexural and fracture properties of carbon/basalt/epoxy hybrid composites was investigated. Two types of carbon/basalt/epoxy hybrid composites with a sandwich form were fabricated: basalt skin-carbon core (BSCC) composites and carbon skin-basalt core (CSBC) composites. Fracture tests were conducted and the fracture surfaces of the carbon/basalt/epoxy hybrid composites were then examined using scanning electron microscopy (SEM). The results showed that the flexural strength and flexural modulus of the CSBC specimen respectively were ~32% and ~245% greater than those of the BSCC specimen. However, the interlaminar fracture toughness of the CSBC specimen was ~10% smaller than that of the BSCC specimen. SEM results on the fracture surface showed that matrix cracking is a dominant fracture mechanism for the CSBC specimen while interfacial debonding between fibers and epoxy resin is a dominant fracture process for the BSCC specimen.

• Nuclear Engineering and Technology
• /
• v.31 no.1
• /
• pp.68-79
• /
• 1999

The YGN Units 3&4 plant conditions during shutdown operation were reviewed to identify the possible event scenarios following the loss of shutdown cooling (SDC) event. For the five cases of typical reactor coolant system (RCS) configurations under the worst event sequence, such as unavailable secondary cooling and no RCS inventory makeup, the thermal hydraulic analyses were performed using the RELAP5/MOD3.2 code to investigate the plant behavior following the event. The thermal hydraulic analyses include the estimation of time to boil, time to core uncovery, and time to core heat up to determine the containment closure time to prevent the uncontrolled release of fission products to atmosphere. The result indicates that the containment closure is recommended to be achieved within 42 minutes after the loss of SDC for the steam generator (SG) inlet plenum manway open case or the large cold leg open case under the worst event sequence. The containment closure time is significantly dependent on the elevation and size of the opening and the SG secondary water level condition. It is also found that the containment closure needs to be initiated before the boiling time to ensure the survivability of the workers in the containment. These results will provide useful information to operators to cope with the loss of SDC event.

• Journal of Power Electronics
• /
• v.19 no.6
• /
• pp.1467-1476
• /
• 2019

Grid unbalanced faults can cause core saturation of power transformer and produce lower-order harmonics. These issues increase the electrical stress of power electronic devices and can cause a tripping of an entire HVDC system. In this paper, based on the positive-sequence and negative-sequence impedance model of a VSC-HVDC system as seen from the point of common connection (PCC), the resonance problem is analyzed and the factors determining the resonant frequency are obtained. Furthermore, to suppress over-voltage and over-current during resonance, a novel method using a virtual harmonic resistor is proposed. The virtual harmonic resistor emulates the role of a resistor connected in series with the commutating inductor without influencing the active and reactive power control. Simulation results in PSCAD/EMTDC show that the proposed control strategy can suppress resonant over-voltage and over-current. In addition, it can be seen that the proposed strategy improves the safety of the VSC-HVDC system under unbalanced faults.