• Journal of the Korean Geographical Society
• /
• v.39 no.2
• /
• pp.269-282
• /
• 2004

Luminescence dating of a coastal dune from the Shindu dunefield on the T'aean Peninsula shows that deposition of the dune structure began about 500-600 years ago. The lower section of the dune has remained stable since then but the upper part yields an age of about 30 years, suggesting reactivation or additional deposition since the 1970's. The two samples that were collected from the lower part of the dune at depths of 3.5 m and 2.0 m below the surface differ by an age interval of about 50-70 years. This indicates a net depositional rate of around 2.5 cm a year which is relatively slow for a coastal dune. Whilst only one dune structure has been dated for the time being and even though the dunefield was probably established much earlier in the Holocene, the OSL ages obtained demonstrate that some dunes in the area could be younger than 1000 years. Such chronologies point to a dynamic environment where the dune structures are not permanently fixed. Sedimentological properties of the dune sands are consistent with those of particles initially deposited under subaqueous conditions and then later transported by wind.

• Journal of Korean Society of Steel Construction
• /
• v.19 no.4
• /
• pp.367-381
• /
• 2007

A transmission tower was designed using the structural methodology to assume a simple truss behavior. However, there is a big difference between a simple truss behavior and a real one. A suitable explanation of structural stability is that it is a semi-rigid connection and not the assumed hinged connection. This study proposes an alternative structural-analysis modeling strategy for the transmission tower design. The element models that were considered were the truss element model, the beam element model, and the combined beam-truss element model. This study includes linear static analysis, free-vibration analysis, and elastic buckling analysis with respect to the design load. The results of the analysis indicate that the axial forces, axial stresses, and maximum displacements of the three analytical models are very similar. However, the bending moments and stresses of the beam element model and of the combined beam-truss element model are significantly high. The results of the free-vibration and elastic buckling analyses show that the beam-truss model can be conservatively used for the transmission tower design.

• Korean Journal of Heritage: History & Science
• /
• v.42 no.3
• /
• pp.132-153
• /
• 2009

A lotus flower pattern of the shape of straight and pointed petals has the forms whose lotus flowers are pointed, and is one of the representative forms of lotus flower pattern of Baekjae along with a round and a triangle protruded style. This style of lotus flower pattern was applied to roof-end tiles, halos of Buddhist images, containers of Buddha's bones, head supports, etc. from the Hanseong period to the Sabi period of Baekjae. However most of lotus flower patterns that remain today were used for the tiles of the Sabi period. Many of them were produced under the influence of the Northern Dynasties and the Southern Dynasties of China, and of Goryeo, which implies the active cultural exchange of Baekjae at that time. Among the present lotus flower patterns of the shape of the straight and pointed petals, that of the earliest time is from Gyeongdang district of Poongnab mud castle and belongs to the mid-fifth century. However there is a higher chance that the gradual subsequent excavation and research will find some tiles of the earlier period and other styles can also be unearthed.

• Journal of the Korean Institute of Gas
• /
• v.27 no.3
• /
• pp.27-34
• /
• 2023

Using ammonia as fuel for solid oxide fuel (SOFC) cells has become an attractive topic nowadays due to its high efficiency, environmental friendliness, and ease of storage and transportation. Several configurations of ammonia-fed SOFC systems have been proposed and investigated, demonstrating high electrical efficiency. However, to further enhance efficiency, it is crucial to understand the inefficient components of the system. The exergy concept is well-suited for this purpose, making exergetic analysis essential for ammonia-fed SOFC systems. This study conducts an exergetic analysis for three selected systems: a simple fuel cell system (FC), an anode off-gas recirculation system (RC-FC), and a recirculation system with water removal (RC-WR-FC). The results reveal that the exergetic efficiencies of the FC, RC-FC, and RC-WR-FC are 48.7%, 51.6%, and 58.4%, respectively. In all three systems, the SOFC stack is the main source of exergy destruction. However, other components with relatively low exergetic efficiency, such as the burner, air heat exchanger, and cooler/condenser, offer greater opportunities for improvement.

• Korean Journal of Heritage: History & Science
• /
• v.56 no.4
• /
• pp.24-37
• /
• 2023

This study analyzes the materials and external characteristics of the Angbu-ilgu, a kind of scaphe sundial, which was newly designated as a Korean Treasure in 2022. The Angbu-ilgu Treasure is owned by three institutions - the National Palace Museum Of Korea, Gyeongju National Museum, and Sungshin Women's University Museum - and is similar as a twin in its material, size, outward appearance, as well as production techniques that include casting, silver inlays, and metal joints. The Three-Treasure Angbu-ilgu is made of brass in the ratio of 90.6: 6.0: 1.8 with Cu: Zn: Pb. This composition clearly differs from Treasure No. 845, an Angbuilgu which has a composition ratio of 82.2: 3.7: 11.8 with Cu: Zn: Pb. In this new Angbu-ilgu Treasure, the hemisphere's stand has four vertical pillars sculpted in a dragon pattern and bilateral wings carved in a cloud pattern on the pillars, which are joined to the hemisphere's horizontal ring with rivets and silver solders, respectively. The dragon-in-clouds pillar (雲龍柱) shows the most outstanding formative beauty of the various Angbu-ilgu pillars produced in the late Joseon Dynasty. It can be seen that the altitude of the north pole engraved on the Angbu-ilgu was made after 1713. Production is, however, actually estimated to have occurred close to the 19th century, the era of the Jinju Kang family, who were professional Angbuilgu makers. Hopefully, this study will lead to a historical science and technology review with modern scientific instruments analyzing the materials and external characteristics of the three Angbu-ilgus designated as a Korean Treasure in 2022.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.2
• /
• pp.949-954
• /
• 2013

Generally, structural plates under axial compression should be stiffened by longitudinal stiffeners in order to enhance the buckling strength. Though U-shaped ribs would be more efficient for the stiffened plate system, there is in the absence of a proper design guides or relevant research results. Thus this study is aimed to examine the local buckling behavior of stiffened plates with U-section ribs. 3-dimensional analysis models which include 3 types of U-shaped longitudinal stiffeners were simulated by using the finite element code ABAQUS. The bifurcation analysis were conducted and then the buckling analysis results are compared with the theoretical equation values. It is found that the rotational constraint effect provided by the U-ribs should increase the local buckling strength. Some features drawn from a series of parametric study results are summarized.

• Journal of Conservation Science
• /
• v.16 s.16
• /
• pp.89-103
• /
• 2004

Provenance discrimination of sixty four obsidian artifacts found in the Korean Peninsular has been carried out using major elements, minor elements and magnetic properties. Most of obsidians in this study were classified into the subalkaline series based on the contents of $Al_2O_3,\;CaO,\;and\;Na_2O+K_2O$ in samples. Provenance & obsidians were classified into three major groups using major elements and minor elements analyse. This result suggests that there are no correlations among the three groups whose provenances are different. Although the magnetic properties of obsidians do not yield clear groupings according to the archaeological site, the bivariate plot for the magnetic susceptibility and the saturation isothermal remanent magnetization shows a rough correlation with the results of major and minor elements analyses.

• Journal of Life Science
• /
• v.18 no.3
• /
• pp.298-303
• /
• 2008

Using a phage peptide library approach, we have isolated a peptide ligand that binds to transferrin receptor on the surface of human melanoma cell, B16F10. The library was first screened twice by recovering internalized phages and was further screened three times by competitively eluting transferrin receptor-specific phages with human transferrin among the phages bound to the cell surface. The peptides displayed by the selected phages were fused to translocation and catalytic domain of Pseudomonas exotoxin to prepare recombinant toxins. After estimating cytotoxicity of each recombinant toxin toward B16F10 cell, seven clones were selected. Sequence analysis revealed that one of the clones displayed a peptide which had a significant sequence homology with human transferrin. The peptide was chemically synthesized and was shown to be functional in delivering cytotoxic agents into B16F10 cell via interaction with transferrin receptor.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.31 no.3
• /
• pp.262-272
• /
• 2015

Loss of molar support and abnormal jaw relationship lead to occlusal disharmony and cause pathologic signs. Full mouth rehabilitations with reestablishment of occlusal schemes are needed. In this case, the 75 year-old female patient showed posterior bite collapse, irregular occlusal plane and Class II jaw relationship. By observing her profile and interocclusal distance, she was diagnosed as loss of occlusal vertical dimension. Treatment plan is to restore maxillay class I removable partial denture and mandibular fixed prosthesis and to establish vertical dimension and harmonious occlusal plane. Occlusal vertical dimension of 19 mm, which is obtained by 7.5 mm increase between maxillary right lateral incisor and mandibular canine, was established using temporary prosthesis via diagnostic wax-up. Patient adaptation with newly formed vertical dimension was verified during 8 week follow-up period. Within the information of interim prostheses, final restoration was constructed and delivered. The patient showed sound occlusal scheme and esthetic profile.

• The Journal of Korean Academy of Prosthodontics
• /
• v.57 no.3
• /
• pp.238-244
• /
• 2019

Soft liner is used to functional impression technique when dental stone is immediately poured after taking impression because of viscoelasticity. In this case, a 78-year-old male visited for new dentures. Due to severe resorption of mandibular edentulous ridge, functional impression taking by closed mouth technique was planned. First of all, making maxillary and mandibular provisional dentures was done, and lined by soft liner to rehabilitate pressured maxillary and mandibular edentulous ridge. After this, Functional impression was taken by closed mouth technique using provisional dentures which are transformed to healed maxillary and mandibular edentulous ridge, and final denture were fabricated using maxillary provisional denture as a reference of artificial teeth arrangement. Consequently, restoring a complete edentulous patient with taking functional impression using provisional dentures resulted in recovering satisfying retention and function.