• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.1
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• pp.27-35
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• 2015

The material properties of crack growth models at an elevated temperature were derived from the results of numerous crack growth tests for Mod.9Cr-1Mo (ASME Grade 91) steel specimens under fatigue loading and creep loading at an elevated temperature. These crack growth models were needed for defect assessment under creep-fatigue loading. The mathematical crack growth rate models for fatigue crack growth (FCG) and creep crack growth (CCG) were determined based on the test results, and the models were compared with those of the French design code RCC-MRx to investigate the conservatism of the code. The French design code RCC-MRx provides an FCG model and a CCG model for Grade 91 steel in Section III Tome 6. It was shown that the FCG model of RCC-MRx is conservative, while the CCG model is non-conservative compared with the present test data. Thus, it was shown that further validation of the property was required. Mechanical strength tests and creep tests were also conducted, and the test results were compared with those of RCC-MRx.

• Korean Journal of Ichthyology
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• v.32 no.2
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• pp.39-48
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• 2020

The slender shinner (Pseudopungtungia tenuicorpa), a tiny freshwater fish of about 8 to 10 cm belonging to Cyprinidae, is an endangered species found only in the Han and Imjin Rivers on the Korean Peninsula. During the breeding season, this species spawns in nests of Coreoperca herzi, a predator of this species, or small crevices on rocks. This unique reproductive ecology can make this species more vulnerable to anthropogenic perturbance that can further limit the places to spawn. Here, mtDNA and microsatellite loci were analyzed to identify the genetic diversity and structure of slender shinners and further to provide the basic data necessary for the conservation planning of this species. A total of 28 polymorphic microsatellite markers were developed using Illumina paired-end sequencing, and 67 slender shinners collected from three localities in the Han River were genotyped using these loci. This species showed a remarkably high level of genetic diversity with mean expected heterozygosity of 0.914 and mean allele number per locus of 27.9, and no signature of drastic demographic decline was detected. As a result of our microsatellite analysis, the genetic structure between the two stems of the Han River, North Han and South Han, was prominent. Such a genetic structure was also evident in the sequence analysis of 14 haplotypes obtained from mtDNA control region. Although slender shinners are only found in very limited areas around the world, the genetic structure indicates that there is a block of gene flow among the populations, which should be reviewed in the future if management and restoration of this species is needed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.6
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• pp.26-37
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• 2019

This paper aims to investigate the seismic characteristics of strip-type damping devices possessing optimized shapes for the moment-resisting mechanism throughout analytical and experimental studies. Predicting equations for initial stiffness and yielding strength were introduced and compared with analytical results obtained from finite element analyses (FEAs) using commercial FEA program ABAQUS. In order for establishing predicting equations, two idealized processes were considered and both predicting equations showed that they could provide enough approximations for seismic applications in building structures. Throughout experimental studies, it was noted that structural uncertainties on mild steels, connection details and structural types linking damping devices with building structures could interrupt predicting structural behavior of the devices. Also, it was observed that shear stress concentrations should be considered if shear yielding type devices are applied into building structures. Nevertheless, it was shown that structural conservatism can be established using the predicting equations and seismic applications of the damping devices can enhance the seismic performance of building structures efficiently in the viewpoint that they have high resistance to low-cycle fatigue failures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.1-12
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• 2017

In this study, It was purpose to provide preliminary data for extension of the applicability of deep corrugated steel plate composite members by steel grade and shear reinforcement method. From the result of flexural test on deep corrugated plates composite members using GR40 and SS590, positive moment capacity was increased about 28% by SS590 steel. But to change steel grade was proved to have insignificant effects for increasement of negative moment capacity. In the moment test result of same overlapping length, Increasement rate of positive and negative moment capacity was not significantly improved by increasing the number of bolt. It was estimated to be due to the characteristics of bolt connection such as distance between centers of bolts, edge distance of bolt. In the test result on the spacing of shear reinforcement, positive moment capacity was increased and deformation of negative moment was reduced as the distance decrease. In the test result on the shape of shear reinforcement, positive and negative moment resistance was increased about 2% ~ 7% by U shaped shear reinforcement. In conclusion It was estimated that moment capacity of deep corrugated steel plate composite members are depend on steel grade of deep corrugated steel plate, spacing of shear reinforcement and reinforcing bar.

• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.367-374
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• 2010

The transfer slab system is a structural system that transfers the loads from the upper shear wall structure to the lower columns. This is a costly system due to a very thick slab, and the relatively high cost can be mitigated by introducing voids in the slab. However, this system of flat plate containing voids is vulnerable to brittle failure caused by punching shear in vicinity of slab-column connection. Thus, the punching shear capacity of the void system is very important. However, the current code doesn't provide a clear design provision for the strength of slabs with a void section. In this study, experimental study was conducted to investigate the punching shear strength of the void slab system. The shear strength of the specimens was predicted by current code and previous researches. In result, the punching shear strength of the void system is determined as the least value calculated at critical section located a distance d/2 from the face of the column and the center of the void section using the effective area at critical section.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.739-745
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• 2003

Interleukine-1(IL-1)은 여러 가지 기능을 가진 싸이토카인으로써 미생물에 대한 면역반응을 일으킨다. IL-1의 유전자 다형성과 치주질환과의 관련성에 대한 많은 연구가 있어왔지만, 대부분이 백인을 대상으로 한 연구였다. 이후 중국인과 일본인을 대상으로 한 연구에서 IL-1의 유전자 다형성의 분포가 인종간에 차이를 보인다는 점이 발견되었다. 이번 연구에서는 치주적으로 건강한 한국인에서 IL-1${\beta}$-511, IL-1${\beta}$+3954, IL-1RN에 대한 유전자형의 분포를 조사하고자 하였다. 서울대학교 치과병원에 근무하는 치과의사, 치과위생사, 간호조무사 및 서울대학교 치과대학 4학년 학생 중 치주낭 깊이와 부착소실이 4mm 이하인 치주적으로 건강한 한국인 65명을 대상으로 하였다. IL-1${\beta}$-511, IL-1${\beta}$+3954, IL-1RN의 유전자 다형성은 분리한 DNA에 각 대립유전자에 특이성을 지닌 primer를 넣고 PCR(Polymerase Chain Reaction)법을 이용하여 증폭시킨후 전기영동법을 이용하여 각 대립유전자의 존재를 확인함으로써 결정하였다. IL-1${\beta}$-511 대립유전자 11, 대립유전자 12, 대립유전자 22의 유전자형에 대하여 각각 23.1%, 49.2%, 26.2%의 분포를 보였다. IL-1${\beta}$+3954의 유전자 다형성은 대립유전자 11, 대립유전자 12의 유전자형에 대하여 각각 89.2%, 10.8%의 분포를 보였으며, 대립유전자 22의 유전자형을 갖는 사람은 한명도 발견되지 않았다. IL-1RN의 유전자형은 5가지의 대립유전자 중에서 1, 대립유전자 2, 대립유전자 4만일 발견되었으며, 대립유전자 11, 대립유전자 12, 대립유전자 14의 유전자형이 86.2%, 12.3%, 1.5%로 분포하였다. 이를 바탕으로 각 대립유전자의 발생빈도 계산한 결과 IL-1${\beta}$-511에서는 대립유전자 1과 2의 비율이 거의 유사하였으나 (47.7%, 52.3%), IL-1${\beta}$+3954, IL-1RN에서는 대립유전자 1이 90%이상 발견되었으며, 또한 대립유전자 1외의 다른 대립유전자가 발견된 경우, 모두 이형접합체였다. 이 연구는 IL-1${\beta}$-511, IL-1${\beta}$+3954, IL-1RN에 대한 유전자형의 분포를 조사한 것으로 한국인에서 이들 유전자의 유전자형의 분포는 백인에서의 분포와 차이를 보이고 있었다. 이후 치주질환자의 유전자형 분포와의 비교로 치주질환과 IL-1${\beta}$-511, IL-1${\beta}$+3954, IL-1RN의 유전자다형성과의 관련성에 관한 추가적인 연구가 필요할 것으로 여겨진다.

• Journal of the Korean Electrochemical Society
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• v.15 no.2
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• pp.109-114
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• 2012

The cathode catalyst layer in polymer electrolyte membrane fuel cells (PEMFCs) was fabricated with anodic aluminum oxide (AAO) template and its structure was characterized with scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The SEM analysis showed that the catalyst layer was fabricated the Pt nanowire with uniform shape and size. The BET analysis showed that the volume of pores in range of 20-100 nm was enhanced by AAO template. The electrochemical properties with the membrane electrode assembly (MEA) were evaluated by current-voltage polarization measurements and electrochemical impedance spectroscopy. The results showed that the MEA with AAO template reduced the mass transfer resistance and improved the cell performance by approximately 25% through controlling the structure of catalyst layer.

• Journal of Mushroom
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• v.15 no.2
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• pp.78-83
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• 2017

Microsatellite SSR markers were developed and utilized to reveal the genetic diversity of 32 strains of Flammulina velutipes collected in Korea, China, and Japan. From the SSR-enriched library, 490 white colonies were randomly selected and sequenced. Among the 490 sequenced clones, 85 (17.35%) were redundant. Among the remaining 405 unique clones, 201 (49.6%) contained microsatellite sequences. We used 12 primer pairs that produced reproducible polymorphic bands for four diverse strains, and these selected markers were further characterized in 32 Flammulina velutipes strains. A total of 34 alleles were detected using the 12 markers, with an average of 3.42 alleles, and the number of alleles ranged from two to seven per locus. The major allele frequency ranged from 0.42 (GB-FV-127) to 0.98 (GB-FV-166), and values for observed ($H_O$) and expected ($H_E$) heterozygosity ranged from 0.00 to 0.94 (mean = 0.18) and from 0.03 to 0.67 (mean = 0.32), respectively. SSR loci amplified with GB-FV-127 markers gave the highest polymorphism information content (PIC) of 0.61 and mean allele number of five, whereas for loci amplified with GB-FV-166 markers these values were the lowest, namely 0.03 and two. The mean PIC value (0.29) observed in the present study with average number of alleles (3.42). The genetic relationships among the 32 Flammulina velutipes strains on the basis of SSR data were investigated by UPGMA cluster analysis. In conclusion, we succeeded in developing 12 polymorphic SSRs markers from an SSR-enriched library of Flammulina velutipes. These SSRs are presently being used for phylogenetic analysis and evaluation of genetic variations. In future, these SSR markers will be used in clarifying taxonomic relationships among the Flammulina velutipes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.11
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• pp.767-773
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• 2017

Printed Circuit Heat Exchanger (PCHE) has an advantage for exchanging thermal energy between high-pressure and high-temperature fluids because its core is made by diffusion bonding method of accumulated metal thin-plates which are engraved of flow channel. Moreover, because it is possible that the flow channel can be micro-size hydraulic diameter, the heat transfer area per unit volume can be made larger than traditional heat exchanger. Therefore, PCHE can have higher efficiency of heat transfer. The smaller channel size can make the larger heat transfer area per unit volume. But if high pressure fluid flows inside the channel, the channel wall can be deformed, the structure and shape of flow channel and header have to be designed appropriately. In this study, the design methodology of PCHE channel in high pressure environment based on pressure vessel codes was investigated. And this methodology was validated by computational analysis.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.20 no.1
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• pp.24-28
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• 2020

Type III Glycogen storage disease (Type III GSD, OMIM#232400) is a genetic metabolic disorder in which undigested glycogen accumulates in the organs due to lack of glycogen debranching enzyme caused by AGL mutation. The clinical symptoms of type III GSD include hepatomegaly, delayed growth, hypoglycemia and muscle weakness. These clinical symptoms are similar to those of other types of GSD, making it difficult to distinguish clinically. The authors report a case of type III GSD diagnosed by gene panel sequencing. A 11-month old male patient was presented with hepatomegaly. In liver biopsy, glycogen was accumulated in hepatocytes, suggesting GSDs. For differential diagnosis of types of GSD, gene panel sequencing for GSDs was performed. As a result, two novel pathogenic compound heterozygous variants: c.311_312del (p.His104Argfs*15) and c.3314+1G>A in AGL were detected and the patient was diagnosed as type III GSD. After diagnosis, he started dietary treatment with cornstarch, and has been free from complications. After two years, two same variants were also identified in the chorionic villous sampling of the pregnant mother, and the fetus was diagnosed as type III GSD. Gene panel sequencing is useful for diagnosis of disease which is indistinguishable by clinically and has high genetic heterogeneity, such as GSD. After diagnosis, familial genetic analysis can provide adequate genetic counseling and rapid diagnosis.