• Economic and Environmental Geology
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• v.26 no.4
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• pp.519-539
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• 1993

A total of 264 independently oriented core samples were collected from 26 sites in the southwestern part (the Naktong Trough) of the Cretaceous $Ky{\check{o}}ngsang$ Basin in south Korea. The sampled formations comprise the sedimentary Shindong and the Hayang Groups of the Lower Cretaceous age. Alternating field and thermal demagnetizations were conducted. Characteristic remanent magnetization (ChRM) was relatively easily isolated in each formation except in the Chinju formation, from which only remagnetization circles were observed. Even though an extensive use of the fold test was not possible due to the nearly homoclinal nature of the strata in the area, we believe that the ChRM of each formation is of primary origin based on the following grounds: The in-situ ChRM direction of each formation is different from the present geomagnetic field direction. Fisherian precision parameter becomes enhanced through the tilt correction in all formations, closely to the values required for a positive fold test. Three out of the five studied formations pass the reversal test. The mean palaeomagnetic pole position from the studied area is found to be statistically different from the contemporary pole from the Chinese block exclusive of the Shandong area. The difference in magnetic declination suggests a $14.5^{\circ}$ (${\pm}10.5^{\circ}$) clockwise rotation of the studied area relative to the Chinese block comprising the west of the Tan-Lu fault. On the other hand, any significant difference in magnetic inclination and concurrent palaeolatitude is not observed between the studied area and China as well as the other area (Taegu-Andong area) in the $Ky{\check{o}}ngsang$ Basin. The dual nature of the magnetic polarity confirmed in all formations suggests an older than 124 Ma (Neocomian or older) age of the studied sedimentary strata.

• Journal of the Korean Geographical Society
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• v.28 no.2
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• pp.77-98
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• 1993

The intent of this study is to analyze the characteristics of distribution, patter, and deposits of the exposed debris slope landform by aerial photography interpretation, measure-ment on the topographical maps and field surveys in the southern part Taebaek mountains. It also aims to research the arrangement types of mountain slope and the landform development of debris slopes in this area. In conclusion, main observations can be summed up as follows. 1. The distribution characteristics 1)From the viewpoint of bedrocks, the distribution density of talus is high in case of the bedrock with high density of joints, sheeting structures and hard rocks, but that of the block stream is high in case of intrusive rocks with the talus line. 2)From the viewpoint of bedrocks, the distribution density of talus is high in case of the bedrock with high density of joints, sheeting structures and hard rocks, but that of the block stream is high in case of inrtusive rocks with the talus line. 2) From the viewpoint of distribution altitude, talus is mainly distributed in the 301~500 meters part above the sea level, while the block stream is distributed in the 101~300 meters part. 3) From the viewpoint of slope oriention, the distribution density of talus on the slope facing the south(S, SE, SW) is a little higher than that of talus on the slope facing the north(N, NE, NW). 2. The Pattern Characteristics 1) The tongue-shaped type among the four types is the most in number. 2) The average length of talus slope is 99 meters, especially that of talus composed of hornfels or granodiorite is longer. Foth the former is easy to make free face; the latter is easdy to produce round stones. The average length of block stream slope is 145 meters, the longest of all is one km(granodiorite). 3) The gradient of talus slope is 20~45${^\circ}$, most of them 26-30${^\croc}$; but talus composed of intrusive rocks is gentle. 4) The slope pattern of talus shows concave slope, which means readjustment of constituent debris. Some of the block stream slope patterns show concave slope at the upper slope and the lower slope, but convex slope at the middle slope; others have uneven slope. 3. The deposit characteristics 1) The average length of constituent debris is 48~172 centimeters in diameter, the sorting of debris is not bad without matrix. That of block stream is longer than that of talus; this difference of debris average diameter is funda-mentally caused by joint space of bedrocks. 2) The shape of constituent debris in talus is mainly angular, but that of the debris composed of intrusive rocks is sub-angular. The shape of constituent debris in block stream is mainly sub-roundl. 3) IN case dof talus, debris diameter is generally increasing with downward slope, but some of them are disordered and the debris diameter of the sides are larger than that of the middle part on a landform surface. In block stream, debris diameter variation is perpendicularly disordered, and the debris diameter of the middle part is generally larger than that of the sides on a landform surface. 4)The long axis orientation of debris is a not bad at the lower part of the slope in talus (only 2 of 6 talus). In block stream(2 of 3), one is good in sorting; another is not bad. The researcher thinks that the latter was caused by the collapse of constituent debris. 5) Most debris were weathered and some are secondly weathered in situ, but talus composed of fresh debris is developing. 4. The landform development of debris slopes and the arrangement types of the mountain slope 1) The formation and development period of talus is divided into two periods. The first period is formation period of talus9the last glacial period), the second period is adjustment period(postglacial age). And that of block stream is divided into three periods: the first period is production period of blocks(tertiary, interglacial period), the second formation period of block stream(the last glacial period), and the third adjustment period of block stream(postglacialage). 2) The arrangement types of mountain slope are divided into six types in this research area, which are as follows. Type I; high level convex slope-free face-talus-block stream-alluvial surface Type II: high level convex slope-free face-talus-alluvial surface Type III: free face-talus-block stream-all-uvial surface Type IV: free face-talus-alluval surface Type V: talus-alluval surface Type VI: block stream-alluvial surface Particularly, type IV id\s basic type of all; others are modified ones.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.663-670
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• 2005

DIN CK35 (JIS S35CK) steels have been used as a material in fuel pump blocks for marine engines. Failures in the inner surface of a drilling hole, due to the initiation of fatigue cracks have been frequently reported. However, the mechanism initiating these cracks and growths has not been clearly diagnosed yet. This study was conducted using a scraped fuel pump block, containing an initiated fatigue crack in the inner surface of a drilling hole. Initially, the cracks and fractured surfaces inside the block were investigated using an optical microscope and a SEM (Scanning Electron Microscope). In addition, microstructure observation, fatigue life test and fatigue crack growth test were performed using a specimen, which was taken from the same block. Results from these tests are summarized as follows; (1) The early crack in the block was supposed to occur inside the inner surface of the drilling hole. (2) The fatigue endurance of this material was about 330 Mpa. (3) The early crack was generated in the cavitations created by the breakdown of a big inclusion, or separation between the big inclusion and the base metal, in which the fundamental ingredients of the inclusion were C, 5, and Mn. (4) In order to prevent these types of failures, the suppression of inclusions inflow by improving the casting process, formation of fine inclusions by applying a heat treatment process, and coating of the surface of the drilling hole were required.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.6
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• pp.27-37
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• 2019

This study focused on the possibility of reducing the cooling load through the change of micro climate in the outdoor space during summer season. This study proposes an efficient planning model by comparing the effects of urban heat island mitigation through wind path planning, outdoor space vegetation, and exterior material change by using the basic model of the street-oriented block housing proposed in the previous research by the same author. As a result, the most effective wind path planning strategy in the street-oriented block housing was the change of the air flow through the mass height adjustment. When the tall building masses were staggered and arranged in a balanced manner, the overall wind environment could be improved. The greater the height difference between low and high masses, the better the air flow was shown. It was also important to arrange the building masses so that the inlet of the main wind was open and to allow the external space to connect to the adjacent block to create a continuous flow. The change of outdoor space vegetation and flooring, and the formation of wind paths through the opening of lower part also showed the effect of heat island reduction. In addition, the change of PMV in summer was the biggest influence of shadow by tall building mass. Attention should be paid to the fact that high-albedo exterior materials are adversely affected by multiple reflections in dense street-oriented block housing. The use of albedo of the exterior material showed that it is necessary to pay attention to apply in the high density block housing. This is attributed to the rise of the temperature due to the absorption of energy into the low-albedo flooring, where the high-albedo exterior causes multiple reflections.

• Macromolecular Research
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• v.16 no.1
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• pp.66-69
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• 2008

• Polymer(Korea)
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• v.28 no.3
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• pp.211-217
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• 2004

The sol to gel transition of aqueous solution of block copolymers consisting of methoxy poly (ethylene glycol) (MPEG) and biodegradable polyesters such as $\varepsilon$-caprolactone and L-lactide was investigated as a function of temperature. MPEG-PCL was prepared by ring opening polymerization of $\varepsilon$-caprolactone in the presence of HClㆍEt$_2$O as monomer activator at room temperature. Also, MPEG-PLLA was prepared by ring opening polymerization of L-lactide in the presence of stannous octoate at 115$^{\circ}C$. The properties of block copolymers were investigated by $^1$H-NMR, IR, and GPC as well as the observation of thermo sensitive phase transition in aqueous solution. As the hydrophobic block length increased, the sol to gel transition temperature increased and curve of that steepen to lower concentration. To confirm the gel formation at body temperature, we observed the formation of gel in the mice body after injection of 20 wt% aqueous solution of each block copolymer. After surging, we investigated the gelation in mice. The results obtained in this study confirmed the feasibility as biomaterials of injectable implantation for controlled release of drug and protein delivery.

• Journal of the Korean Geotechnical Society
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• v.32 no.12
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• pp.33-43
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• 2016

In order to analyze ground relaxation and cavity formation mechanism due to deteriorated sewer pipe, field test was carried out and a numerical assessments were compared with the field test results. An artificial underground cavity was intended using the ice block overlaying the buried pipe and confirmed that the cavity and relaxation of the surrounding ground were gradually formed as the ice block starts to melt down. Such mechanism was highly suspected to be involved with soil particle interlocking as a soil compaction was a typical process for the buried pipes. In exploring such mechanism numerically, commercially available DEM (Discrete Element Method) code PFC2D was used and the interlocking induced cavern behaviors were successfully simulated and compared with field test results by utilizing the clump logic imbedded in PFC code.

• Geosciences Journal
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• v.23 no.4
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• pp.547-556
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• 2019

A new species of the most primitive rosenellid stromatoporoid Cystostroma, C. primordia sp. nov. is reported from the Hunghuayuan Formation (Lower Ordovician, Floian) of Guizhou Province in the South China Block and the Duwibong Formation (Middle Ordovician, Darriwilian) of the Taebaeksan Basin in mid-eastern Korea (North China Block). This species is the first representative of the genus found in both the North and South China blocks. Cystostroma primordia sp. nov. is characterized by the absence of denticles and distinctively smaller cyst plates (height 0.04-0.20 mm, length 0.09-0.39 mm) than any other known species of Cystostroma. The presence of C. primordia sp. nov. in Lower to Middle Ordovician strata of western Gondwana challenges the long-held view of the late Middle Ordovician emergence of Paleozoic stromatoporoids. The simple internal morphological features of this new species and its occurrence in the Lower Ordovician of South China strongly indicate that an Early Ordovician Cystostroma-type precursor from western Gondwana is located near the base of the stromatoporoid stock. This occurrence greatly preceded the late Middle Ordovician (late Darriwilian) stromatoporoid diversification in circum-equatorial regions worldwide.

• Biomedical Science Letters
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• v.12 no.4
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• pp.343-348
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• 2006

Drosophila Sog and vertebrate Noggin play important roles during development. They function as antagonists against BMP4 signaling and induce neural ectoderm during embryogenesis. They are also engaged in appendage formation by inhibiting BMP4 signaling during late development. To understand further functions of Sog, Supersog, which is a more potent form of Sog, and Noggin BMP4 antagonists during development, I performed the molecular genetic analysis using Drosophila embryogenesis and wing formation as assay systems. In cellular blastoderm embryos, Sog inhibited Dpp signaling, Drosophila BMP4 signaling, whereas Supersog or Noggin did not block Dpp signaling. During wing formation, Sog inhibited Sax type I receptor of Dpp signaling whereas Noggin inhibited Tkv type I receptor of Dpp signaling. However, Supersog inhibited both Sax and Tkv type I receptors. These results suggest that functions of BMP4 antagonists are developmental stage dependent and indicate that each BMP4 antagonist inhibits BMP4 signaling by blocking different BMP4 receptors.

• Proceedings of the Ginseng society Conference
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• 1998.06a
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• pp.263-269
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• 1998

It is an established fact that most of the carcinogens implicate bay-region diol epoxides as the ultimate carcinogenic metabolites. These electrophiles react with nucleophilic sites in the cells to form abducts. It is the formation of carcinogenic-DNA adducts that is thought to initiate carcinogenesis. In our previous study we have reported chemopreventive property of Ginseng on 7,12-dimethylbenz (a)anthracene (DMBA) induced skin papillomagenesis in male Swiss albino mice. In this study we have examined the effect on formation of DMBA-DNA adducts in rat hepatocytes pretreated with ginseng. Primary cultures of rat hepatocytes were used. The cells wets treated with ginseng for 24 hrs and then with DMBA (iOn) for 18 hrs. Cells were then harvested, their DNA was isolated and analyzed by P)2 labelling. A significant reduction in the levels of DMBA-DNA adduces (adducts/108 nucleotides) was observed in all cultures pretreated with ginseng. The viability of cells was not affected by pre-treatment with ginseng. Our finding suggests that ginseng block or suppresses the events associated with chemical carcinogenesis by inhibiting metabolic activation of the carcinogens.