• The Journal of Korean Academy of Prosthodontics
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• v.62 no.4
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• pp.366-374
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• 2024

In a completely edentulous patient who cannot have implant-retained overdentures due to medical history and economic circumstances, a suction-effective complete denture utilizing the closed-mouth impression technique is being used to secure high retention. In this case, both a conventional complete denture using the open-mouth impression technique and a suction-effective complete denture using the closed-mouth impression technique were fabricated for a single completely edentulous patient. The results demonstrated that both methods provided excellent outcomes in terms of function, esthetics, and patient satisfaction. Conventional complete dentures increase the area of denture-bearing pressure to ensure retention and stability, whereas suction-effective complete dentures achieve retention by sealing the entire border of the denture. Since there are characteristic differences in the clinical and laboratory procedures due to differences in the concept of denture fabrication, this was compared through this case report.

• Journal of the Korea Concrete Institute
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• v.28 no.4
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• pp.463-471
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• 2016

A shear strength model for the high-shear ring anchor consisting of a steel ring and a rod was developed based on the shear tests on single high-shear ring anchors. The shear strength was found to be proportional to $f_{ck}{^{0.75}}$ which is a similar characteristic to the strength of shear connectors used in composite structures. The effects of the compressive strength of concrete, edge distance, and embedment length of rod are included in the proposed model. Comparison with 22 tests shows that the average and the coefficient of variation of test-to-prediction ratios are 1.01 and 7.57%, respectively. Push tests on the specimens having four high-shear ring anchors at each face were conducted and the measured shear strengths were compared with the predictions by the proposed model. For the specimen with an edge distance of 100 mm, a splitting failure occurred and for the specimens with an edge distance of 150 mm, a failure mode mixed with splitting and bearing occurred, which were very similar to the failures of shear tests on single high-shear ring anchors. In case of a splitting failure, the overlap of failure surfaces could be prevented by providing the longitudinal spacing of 400 mm which is four times of the edge distance. In case of a bearing failure, the failure area is less than 150 mm from the center of the anchor and therefore the overlap of failure surfaces could be prevented by providing the longitudinal spacing of 200 mm. The average of the test-to-prediction ratios of Push tests is 98%, which means that the proposed mode can be applied to predict the shear strength of the multiple high-shear rings.

• Korean Journal of Heritage: History & Science
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• v.52 no.2
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• pp.122-141
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• 2019

This study aimed to provide new interpretations of the ceramics excavated from the archaeological site of the royal palace of Goryeo (918~1392), where only limited access was permitted due to its location in Gaeseong, North Korea. The interpretations were based on the existing understanding of the arrangement of the palace buildings at the site and historical records. The study of the general aspects of the celadons discovered during eight excavations at the Goryeo Palace site in Gaeseong revealed that most of the vessels found at the site were produced during the early and middle phases of the Goryeo dynasty. The study involved classifying the celadons bearing inscribed texts and symbols into 18 different types according to their characteristic features and periods of production. The inscribed celadons have provided detailed information of the site where they were found, thereby making it possible to make strong presumptions about the date of construction, function, and status of the building in the palace connected with the discoveries. The excavations from the Goryeo Palace site and related historical literature suggest that the celadons bearing the inscription "Sojeon (燒錢)" were used during the first half of the 13th century, although the existing view had been that they were used during the second half of the century. This new conclusion is based on the use of the symbols ${\circ}$ and ${\odot}$, the celadons found together with the Sojeon-inscribed celadons, the date of the celadons bearing the inscription "Seong (成)," and the location of their discovery behind the site of Seongyeongjeon (aka Hoegyeongjeon) Hall, which had been one of the main palace buildings. The Taoist rituals performed for the safety of the Goryeo dynasty were largely held at Ganganjeon (aka Daegwanjeon) Hall in the western part of the royal palace during the second half of the 13th century. It was mostly in the first half of the 13th century just before the transfer of the Goryeo government from Gaeseong to Ganghwa (1232~1270) that the Taoist rituals were held at the location near Seongyeongjeon Hall, where archaeologists found the Sojeon-inscribed celadons. Therefore, the large number of celadon cups with holders, including those inscribed with Sojeon, discovered during the eighth excavation of the palace site suggests that they were used for the rituals held at Seongyeongjeon Hall during the first half of the 13th century.

• Economic and Environmental Geology
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• v.28 no.4
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• pp.337-350
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• 1995

The Hwacheon-ri mineralized area is located within the Cretaceous Gyeongsang Basin of the Korean peninsula. The mineralized area includes the Hwacheon, Daeweon, Kuryong and Cheongryong mines. Each of these mines occurs along copper-bearing hydrothermal quartz veins that crosscut late Cretaceous volcanic rocks, although some disseminated ores in host rocks also exist locally. Mineralization can be separated into three distinct stages (I, II, and III) which developed along preexisting fracture zones. Stage I is ore-bearing, whereas stages II and III are barren. The main phase of ore mineralization, stage I, can be classified into three substages (Ia, Ib and Ic) based on ore mineral assemblages and textures. Substage Ia is characterized by pyrite-arsenopyrite-molybdenite-pyrrhotite assemblage and is most common at the Hwacheon deposit. Substage Ib is represented by main precipitation of Cu, Zn, and Pb minerals. Substage Ic is characteristic of hematite occurrence and is shown only at the Kuryong and Cheongryong deposits. Some differences in the ore mineralization at each mine in the area suggest that the evolution of hydrothermal fluids in the area varied in space (both vertically and horizontally) with respect to igneous rocks relating the ore mineralization. Fluid inclusion data show that stage I ore mineralization mainly occurred at temperatures between ${\approx}350^{\circ}$ and ${\approx}200^{\circ}C$ from fluids with salinities between 9.2 and 0.5 wt.% eq. NaCl. In the waning period of substage Ia, the high temperature and salinity fluid gave way to progressively cooler, more dilute fluids of later substage Ib and Ic (down to $200^{\circ}C$, 0 wt.% NaCl). There is a systematic decrease in the calculated ${\delta}^{18}O_{H2O}$ values with paragenetic time in the Hwacheon-ri hydrothermal system from values of ${\approx}2.7$‰ for substage Ia, through ${\approx}-2.8$‰ for substage Ib, to ${\approx}-9.9$‰ for substage Ic. The ${\delta}D$ values of fluid inclusion water also decrease with decreasing temperature (except for the Daeweon deposit) from -62‰ (substage Ia) to -80‰ (substage Ic and stage III). These trends are interpreted to indicate the progressive cooler, more oxidizing unexchanged meteoric water inundation of an initial hydrothermal system which is composed of highly exchanged meteoric water. Equilibrium thermodynamic interpretation of the mineral assemblages with the variation in amounts of chalcopyrite through the paragenetic time, and the evolution of the Hwacheon-ri hydrothermal fluids indicate that the solubility of copper chloride complexes in the hydrothermal system was mainly controlled by the variation of temperature and $fo_2$ conditions.

• Economic and Environmental Geology
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• v.18 no.4
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• pp.399-410
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• 1985

Bentonites from the Janggi Group of the Lower Miocene age from the Geumgwangdong area, Korea, have been studied for mineralogical and genetic characterization. The Janggi Group is subdivided, in ascending order, into the Janggi Conglomerate, the Nuldaeri Tuff, the Geumgwangdong Shale, the Lower Coal-bearing Formation, the Basaltic Tuff, and the Upper Coalbearing Formation. Bentonites occur as thin or thick beds in all sedimentary units of the Janggi Group, except for the Janggi Conglomerate. Significant bentonite deposits are found in the Nuldaeri Tuff, the Lower Coal-bearing Formation and the Basaltic Tuff. Bentonites consist mainly of smectite (mainly montmorillonite), with minor quartz, cristobalite, opal-CT and feldspar. Occasionally, kaolinite, clinoptilolite or gypsum is associated with bentonites. Bentonites were studied by the methods of petrographic microscopy, X-ray diffraction, thermal analysis (DT A and TG), infrared absorption spectroscopic analysis, SEM, intercalation reaction, and chemical analysis. Smectites commonly occur as irregular boxwork-like masses with characteristic curled thin edges, but occasionally as smoothly curved to nearly flat thin flakes. Most of smectites have layer charge of 0.25-0.42, indicating typical montmorillonite. Crystal-chemical relations suggest that Fe is the dominant substituent for Al in the octahedral layer and there are generally no significant substituents for Si in the tetrahedral layer. Ca is the dominant interlayer cation in montmorillonite. Therefore, montmorillonite from the study area is dioctahedral Ca-montmorillonite. Occurrence and fabrics of bentonites suggest that smectites as well as cristobalite, opal-CT and zeolites have been formed diagenetically from tuffaceous materials. The precursor of smectites is trachytic or basaltic tuff. Smectites derived from the former contain relatively more $Al_2O$ a and less $Fe_2O_3$ than those from the latter.

• Archives of Plastic Surgery
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• v.34 no.5
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• pp.659-662
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• 2007

Purpose: Multiple skin leiomyoma and uterine myoma bearing autosomal dominant traits are benign smooth muscle tumors which originate in skin or female uterus. Skin leiomyoma occurs after gene mutation originating from arrector pili muscle of hair follicle where its clinical manifestations vary significantly from person to person. Our department hereby reports the histological findings and genetic evaluations of this very rare disease. Methods: A 57-year-old woman presented in our institute with multiple tumors in the left and central parts of her back that started to appear since 19 years ago. The patient was diagnosed as having uterine myoma 15 years ago and underwent hysterectomy. Biopsy has been done on the specimen, and genomic DNA was separated from Fumarate hydratase gene for it to go through PCR amplification. The results of PCR amplification were aligned by sequencer. Results: According to the results of biopsy, tumor cells were spindle-shaped and were aligned in a bundle where there was no dysplasia or mitosis. Moreover, these cells had abundant eosinophilic cytoplasm with elongated nucleus, and benign leiomyoma that showed positive reactions to SMA stain were found. In genetic examination, mutations such as heterozygous single nucleotide substitutions were found in alignments of amplified DNA. Conclusion: Multiple skin leiomyoma and uterine myoma are relatively uncommon diseases that are transmitted through autosomally dominant traits from genetic mutations. When a patient's chief complaint lies upon skin-colored or brown masses that occur in multiples appearing in the trunk or extremities with characteristic clinical symptoms and histological findings, and when the patient's family history is acknowledged such as skin or uterine leiomyoma or renal tumor, necessary genetic examination on multiple skin leiomyoma and uterine myoma could be done, and thereby precise diagnosis could also be made.

• Journal of the Korean Society for Railway
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• v.20 no.1
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• pp.64-75
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• 2017

The role of a track subgrade is to provide bearing capacity and distribute load transferred to lower foundation soils. Track subgrade soils are usually compacted by heavy mechanical machines in the field, such that sometimes they are attributed to progressive residual settlement during the service after construction completion of the railway track. The progressive residual settlement generated in the upper part of a track subgrade is mostly non-recoverable plastic deformation, which causes unstable conditions such as track irregularity. Nonetheless, up to now no design code for allowable residual settlement of subgrade in a railway trackbed has been proposed based on mechanical testing, such as repetitive triaxial testing. At this time, to check the DOC or stiffness of the soil, field test criteria for compacted track subgrade are composed of data from RPBT and field compaction testing. However, the field test criteria do not provide critical design values obtained from mechanical test results that can offer correct information about allowable permanent deformation. In this study, a test procedure is proposed for permanent deformation of compacted subgrade soil that is used usually in railway trackbed in the laboratory using repetitive triaxial testing. To develop the test procedure, an FEA was performed to obtain the shear stress ratio (${\tau}/{\tau}_f$) and the confining stress (${\sigma}_3$) on the top of the subgrade. Comprehensive repetitive triaxial tests were performed using the proposed test procedure on several field subgrade soils obtained in construction sites of railway trackbeds. A permanent deformation model was proposed using the test results for the railway track.

• The Journal of the Petrological Society of Korea
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• v.11 no.3_4
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• pp.138-156
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• 2002

Precambrian metamorphic rocks of southwest Sobaeksan massif consist of mainly granitic gneiss, porphyroblastic gneiss and quartzofeldspathic gneiss. The orthopyroxene-bearing rocks(charnockites) are found in the west of Hadong-Sancheong anorthosite complex. The charnockites are 3km wide, 12km long and divided into massive and foliated types based on their texture. The compositions of charnockites are comparable to granodiorite to adamellite and subalkaline. Variations in major and trace elemental abundances show typical magmatic differentiation trends. The geochemical data plotted on tectonic discrimination diagrams reveal that these charnockites were formed in the active tectonic environment. The massive and folidated charnockites are mainly composed of plagioclase, orthopyroxene, microcline, quartz and disseminated garnet. Camels generally show characteristic zonal textures with decreasing $X_{alm}$(0.74~0.83), $X_{Py}$ (0.07~0.12) and $X_{Mg}$ (0.12~0.08) and increasing $X_{grs}$(0.03~0.15) from core to rim. Metamorphic temperature and pressure of the charnockites estimated from orthopyroxene-garnet-plagioclase-quartz assemblages show wide range of variation of $600~900^{\circ}C$ and 2.5~7.5 kbar respectively. The results of P-T estimates indicate an anticlockwise P-T evolution path.

• Analytical Science and Technology
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• v.31 no.2
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• pp.78-87
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• 2018

Asian lacquer has been used as an adhesive and coating material in Asian countries, such as China, Japan, and Korea, and other southeast Asian countries. In this study, the changes in the chemical structure of lacquer with drying was analyzed using pyrolysis/GC/MS (which is useful in analyzing polymeric material) to understand its drying procedures. Upon increasing temperature, the dried lacquer was fully pyrolyzed above the pyrolysis temperature of $500^{\circ}C$. The repeatability was good at the pyrolysis temperature of $500^{\circ}C$ (rsd = 2.6-22.3 %); however, there were differences in the pyrogram patterns when the difference in sample quantity was large. The characteristic peaks of Asian lacquer components, such as those corresponding to 1,2-benzenediol and 3-methyl-1,2-benzenediol, were detected and the compound of each peak was assigned according to the mass library. As the lacquer dried, the composition of pyrolysis products with urushiol derivatives bearing 3 C=C bonds was severely reduced compared with the ones with no C=C bonds, indicating that the polymerization is related to C=C bonds. These results can be applied to confirm the presence of lacquer in excavated relics and to monitor the changes in the composition of raw lacquer with drying.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.37-47
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• 2004

Sulfates such as alunite and schwertmannite formed under oxidation condition play a important role in geochemical processes taken place at waste dumps and a creek from Dalseong mine, Daegu. Water chemistry shows pH decreases from upstream toward downstream creek, mainly due to formation of schwertmannite that is the most abundant phase along the creek. The removal of Al from the creek is preferentially attributed to formation of Al-bearing minerals and Al-sulphates. Among them, alunite is the most important Al-sink phase that occurs at higher pH than $pK_1$, Al hydrolysis constant. With high saturation index, alunite formed at the creek has a spherical form, commonly associated with schwertmannite. Secondary minerals formed on the surface of altered or weathered surfaces of heavy metals from the wasted dump that underwent severe oxidation, where alunite has characteristic habits which are spheric, radiating, and botrytis-like aggregates. Natroalunite occurs in association with alunite, or as mixtures of both of them. Because the pH decreases with distance due to formation of schwertmannite, although total contents of dissolved ions slowly lessen at least in the AMD, it is expected that the minerals precipitated at the creek can be exposed to subsequent dissolution, which may induce possible environmental problems.