• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.49.2-49.2
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• 2019

We present results from our long-term observing campaign, using the NASA IRTF at Maunakea, to obtain 2 - 4 ㎛ spectra of 118 red point sources in the line of sight to the Galactic Center (GC). Our sample is largely composed of point sources selected from near- and mid-infrared photometry, but also includes a number of massive young stellar objects. Many of these sources show high foreground extinction as shown by deep 3.4 ㎛ aliphatic hydrocarbon absorption feature, which is a characteristic of the diffuse ISM and comes from the long line of sight through the diffuse medium toward the Central Molecular Zone (CMZ), the central 300 pc region of the GC. The deep 3.1 ㎛ H₂O ice absorption band coming from the local, dense material in the GC CMZ suggests that most sources are likely located in the GC CMZ. A few of these sources show weak CCH₃OH ice absorption at 3.535 ㎛, which can provide a strong constraint on the CCH₃OH ice formation in the unique environment of the CMZ. From the best-fitting models, the optical depths of these features are determined and used to generate a well-rounded view of the ice composition across the GC CMZ and the spectral characteristics of massive YSOs in the GC.

• Advances in Computational Design
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• v.7 no.4
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• pp.281-295
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• 2022

Tensile property is one of the excellent properties of ultra-high performance concrete (UHPC), and uniaxial tensile test is an important and challenging mechanical performance test of UHPC. Traditional uniaxial tensile tests of concrete materials have inherent defects such as initial eccentricity, which often lead to cracks and failure in non-test zone, and affect the testing accuracy of tensile properties of materials. In this paper, an original integrated design scheme of mould and end fixture is proposed, which achieves seamless matching between the tension end of specimen and the test fixture, and minimizes the cumulative eccentricity caused by the difference in the matching between the tension end of specimen and the local stress concentration at the end. The stress analysis and optimization design are carried out by finite element method. The curve transition in the end of specimen is preferred compared to straight line transition. The rationality of the new integrated design is verified by uniaxial tensile test of strain hardening UHPC, in which the whole stress-strain curve was measured, including the elastic behavior before cracking,strain hardening behavior after cracking and strain softening behavior.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.26-26
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• 2020

Daphne L. (Thymelaceae) comprises about 95 species distributing worldwide from N Africa, N India, SE Asia to E Asia and the coast of the Mediterranean of Europe. In Korea, five species of this genus have been described. In this study, we included four species (D. genkwa, D. pseudomezereum, D. kiusiana, D. jejudoensis) from Korea, excluding cultivated D. odora. The morphological characters through local surveys and the re-classification of the specimens collected in the Korea National Herbarium (KH) were carried out and distribution maps for each taxon were also prepared. The major characters include habit, trichomes in winter bud, leaf, and twig, phyllotaxis, inflorescence, size of calyx lobe and trichomes in the calyx tube, etc. The distribution map showed that D. genkwa is mainly distributed in the coastal area of Hwanghaenam-do, Pyeongannam-do, Jeollabuk-do and Jeollanam-do, whereas D. pseudomezereum is distributed in the limestone zone of Gangwon-do, Jeollabuk-do, and Gyeongsangbuk-do. Similarly, D. kiusiana is mostly found in Jeollanam-do, Gyeongsangnam-do, and Jeju-do. In addition, D. jejudoensis is known to be distributed in forests of Murueng, Andeok, and Seonheul-ri in Jeju-do, but recently, new habitat is discovered in the island forest areas of Jeollanam-do. However, some of these individuals showed the characteristics of D. kiusiana, thus before come to any conclusion detailed taxonomic review of D. jejudoensis and D. kiusiana is required.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.3
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• pp.234-238
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• 2007

Three different tidal phase-lag references have been used by the tidal research community of Korea: Greek kappa (k), Local standard time zone ($135^{\circ}E$) phase-lag (g) and Greenwich phase-lag (G). This ununified tidal information system may induce confusion in understanding tidal characteristics and their variability and impede the development of tidal knowledge in Korea. In this study we closely explore the three phase-lag reference definition with respect to their mutual conversion. We also identify an incorrect phase-lag reference definition used in previous works and discuss what has led to this misunderstanding.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4112-4119
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• 2023

This study employs the microshear test method to examine the local mechanical properties of narrow-gap welded joints, revealing the mechanical inhomogeneity by evaluating the microshear strength, stress-strain curves, and failure strain. On this basis, the influence of weld joints micromechanical inhomogeneity on the crack tip opening displacement (CTOD) fracture toughness is investigated. From the root weld layer to the cover weld layer, the fracture toughness at the center of the weld seam demonstrates an increasing trend, with the experimental and calculated CTOD values showing a good correspondence. The microproperties of the welded joints significantly impact the load-bearing capacity and fracture toughness. During the deformation process of the "low-matching" microregions, the plastic zone expansion is hindered by the surrounding microregion strength constraints, thus reducing the fracture toughness. In contrast, during the deformation of the "high-matching" microregions, the surrounding microregions absorb some of the loading energy, partially releasing the concentrated stress at the crack tip, which in turn increases the fracture toughness.

• Archives of Plastic Surgery
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• v.51 no.4
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• pp.417-422
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• 2024

Persistent lymphocele of the groin is a complication of groin surgery that can severely impact the quality of life. The restoration of the interrupted lymphatic pathway is considered by many authors the ideal treatment to prevent a recurrence. However, multiple aspiration procedures and surgical revisions can compromise the availability of local veins needed for a lymphovenular bypass surgery. In addition, surgical debridement of a long-standing lymphocele can generate extensive dead space and contour deformity. A flap delivering additional venules for trans-flap lymphovenular anastomoses (LVAs) can overcome both problems by providing soft tissue and competent veins harvested outside the zone of injury. A successful case of severe groin lymphocele treated with trans-flap LVAs from an abdominal-based flap is presented. The patient was referred to us for a recurrent lymphocele developed in the right groin after lipoma excision that persisted despite multiple surgical attempts. After the identification of patent and draining inguinal lymphatic vessels, a pinch test was used to design a mini-abdominoplasty superficial inferior epigastric artery flap. The superficial veins of the cranial incision were identified and anastomosed to the lymphatic vessels after the pedicled flap harvested and insetted in the groin. The early restoration of lymphatic drainage and the optimal aesthetic outcome supports the combined approach offered by trans-flap LVAs as a valuable therapeutic option for severe and persistent lymphocele.

• Journal of Urban Science
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• v.12 no.1
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• pp.21-34
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• 2023

Based on the theory of network governance, this study aims to establish a n'work governance model and present strategic measures for the use of return donor zones. In a network society, it is difficult for the government to handle complex problems alone, so close cooperation between related agencies has become important. After the return of the USFK base, most of the policies established by the government have not been carried out smoothly, so it is necessary to introduce cooperative network governance.Accordingly, technical statistics were analyzed for camp market business institutions to examine the centrality and structure of network relations (information sharing relationship, idea exchange relationship, civil complaint sharing relationship). As a result of the analysis, the Camp Market Division of Incheon City had the most central role and great influence in the camp market, which was maintained even when the time changed. Currently, it is in the form of a vertical network centered on local governments, but in the future, a horizontal network is suitable to strengthen cooperative relations and must be systematically managed around managers.

• Journal of the Korean Society of Visualization
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• v.22 no.3
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• pp.117-123
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• 2024

This study aims to confirm the feasibility of separating heavy metals and chlorine from fly ash generated in power plants and incinerators, enabling its potential reuse. A closed-loop Venturi system was used as the cavitation generator, applying the Bernoulli principle. Cavitation occurs when local pressure drops below the vapor pressure, and the energy released during the collapse of cavitation bubbles effectively detaches contaminants bound to the surface of the fly ash. Preliminary experiments visualizing cavitation in water confirmed the cavitation occurrence zone. After washing two types of fly ash, component analysis revealed a reduction in chlorine ions by 76-86.1% and lead by 89.5%. In additional experiments using a different fly ash sample, reductions in lead (80.7%), copper (99.5%), and hexavalent chromium (at least 63.6%) were observed. While there may be some errors due to measurement limitations, these results demonstrate the efficiency of this system in cleaning contaminated fly ash.

• Korean Journal of Remote Sensing
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• v.35 no.6_1
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• pp.933-944
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• 2019

This study analyzes the tide deformation of land boundary regions on the east (Region A) and west (Region B) sides of the Ross Ice Shelf in Antarctica using Double-Differential Interferometric Synthetic Aperture Radar (DDInSAR). A total of seven Sentinel-1A SAR images acquired in 2015-2016 were used to estimate the accuracy of tide prediction model and Young's modulus of ice shelf. First, we compared the Ross Sea Height-based Tidal Inverse (Ross_Inv) model, which is a representative tide prediction model for the Antarctic Ross Sea, with the tide deformation of the ice shelf extracted from the DDInSAR image. The accuracy was analyzed as 3.86 cm in the east region of Ross Ice Shelf and it was confirmed that the inverse barometric pressure effect must be corrected in the tide model. However, in the east, it is confirmed that the tide model may be inaccurate because a large error occurs even after correction of the atmospheric effect. In addition, the Young's modulus of the ice was calculated on the basis of the one-dimensional elastic beam model showing the correlation between the width of the hinge zone where the tide strain occurs and the ice thickness. For this purpose, the grounding line is defined as the line where the displacement caused by the tide appears in the DDInSAR image, and the hinge line is defined as the line to have the local maximum/minimum deformation, and the hinge zone as the area between the two lines. According to the one-dimensional elastic beam model assuming a semi-infinite plane, the width of the hinge region is directly proportional to the 0.75 power of the ice thickness. The width of the hinge zone was measured in the area where the ground line and the hinge line were close to the straight line shown in DDInSAR. The linear regression analysis with the 0.75 power of BEDMAP2 ice thickness estimated the Young's modulus of 1.77±0.73 GPa in the east and west of the Ross Ice Shelf. In this way, more accurate Young's modulus can be estimated by accumulating Sentinel-1 images in the future.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.5
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• pp.19-24
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• 2003

We analysed seismic phases recorded by the 10 December 2002 Cheolwon, Korea, earthquake of $M_{L}$ 3.6 and obtained source parameters such as hypocenter, origin time, earthquake magnitude. Velocity and acceleration records used in this study are from the KMA and KIGAM seismic networks. Due to the location of the epicenter in the north of the DMZ(Demilitarized Zone), direct Pg phases were recorded only at five stations in the area south of DMZ. Identification of refracted Pn phase as the first arrival is difficult in most stations. Therefore, the hypocenter determined by existing routine methods could be affected by a large error. In order to avoid the possibility of the problem, we employed a method of seismic phase analysis developed by Kim et al.. The direct, refracted, and reflected P and S phases were successfully identified using the method together with the travel time curve data. In order to improve the accuracy in determination of the hypocenter and origin time, we included PmP and SmS phases in the analysis in addition to the phases such as Pg, Pn, Sg and Sn. The epicenter, depth, and origin time of the Cheolwon earthquake determined based on data of 11 stations within 200km from the epicenter are $38.81^{\circ}$N, $127.22^{\circ}$E, 12.0km, and 7:42:51.4(local time), respectively. The average value of the local magnitude based on the Richter's definition from all the stations is 3.6 in $M_{L}$. This magnitude is smaller by 0.2 and 0.5 compared with magnitudes determined by KMA and KIGAM, respectively.