• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.95-118
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• 1987

This study was undertaken to observe the elemental transition of Interface depending on different pretreatment methods, the number of filings, the kinds of porcelain powders and the various alloys in ceramo-metal restoration. The materials used in this study were Pors-on $4^{(R)}$ and Ceramco porcelain powder to compare the differences depending on the pretreatement methods and the number of firings. Ceramco porcelain powder and Vita porcelain powder were used to compare the differences of elemental transition depending on the porcelain powders. The $Parasil^{(R)},\;PGV^{(R)}$ and Pors-on $4^{(R)}$ as Pd-Ag alloy were used to compare the difference of elemental transition depending on the various alloys. The pretreatment methods were : no treatment, treatment under vacuum and air, treatment with 50 % hydrofluoric acid and double heat tretament. The number of firings were 3, 5 and 7 repeated firings All specimens were observed by SEM and concentration of elements were analyzed quantitatively with EPMA The results of this study were obtained as follows : 1. In the groups of air-treatment, concentration of Sn were the highest and widest. A high concentration of In were in the groups of vacuum and air treatment. 2. There were no significant differences in concentration of Sn between the group of vacuum, 5 minutes hydrofluoric acid and double heat treatment. (p>0.05) 3. As the period of time of hydrofluoric acid treatment increased, not only were the trace elements reduced but the main components such as Pd and Ag were also reduced. 4. Concentration of Sn and In increased and diffused with repeated firings but 5 repeated and 7 repeated firings groups had no significant differences. (p>0.05) 5. Sn were more concentrated in the group of Ceramco porcelaion powder than Vita porcelain powder. 6. The higher concentration of trace elements in the alloy, the more increasing concentration of Sn and In in the interface.

• The Journal of the Petrological Society of Korea
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• v.13 no.4
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• pp.201-213
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• 2004

The Precambrian amphibolites in the central Gyeonggi massif, Yangsuri, Gyeonggido and southeastern Okcheon metamophic belt, Mungyeonggun, Gyeongsangbukdo, Korea, were studied on the geochemical characteristics of major and trace elements, and discussed petrogenetically and geotectonically. The characteristics of major elements of the amphibolites in these study areas are igeous origin such as tholeiitic-, subalkaline and alkaline basalt. Geotectonic distinction diagrams of trace elements such as Ti-Zr-Y and Zr-Nb-Y show basaltic igneous activity of island arc and mid ocean ridge environment at central Gyunggi massif, and within plate environment at southeastern Okcheon metamorphic belt. This result shows that genetic environments of study areas are different. Especially, origin of amphibolites in central Gyeonggi massif is similar with that of western Gyeonggi massif but different with the amphibolites of Chuncheon area. Genetic environment estimated of fractional crystallization of plagioclase has no particular effect on the origin of magma because value of LREE is higher than that of HREE and Eu anomaly definitely don't be exposed.

• Economic and Environmental Geology
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• v.23 no.3
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• pp.329-342
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• 1990

The purpose of this study is to clarify the nature of the differentiation and petrogenesis of igneous rocks in comparison with experimental results based on petrological and geochemical criteria. Study area is composed of the Precambrian granitic gneiss complex, Triassic meladiorite and biotite granodiorite, Jurassic biotite granite, and Cretaceous quartz porphyry. According to the data of EPMA, the clinopyroxene and orthopyroxene of meladiorite come under salite and hypersthene, respectively. Such results suggests that meladiorite is incipient differentiated products of basic magma under slow cooling condition. The petrochemical data of variation diagram of major element oxides vs. silica and of trace element oxide vs. silica, AMF triangle diagram and trace elements suggests that igneous rocks of study area are plutonic rocks belong to calc alkali rock series of the source of comagma intruded-emplaced in the order of meladiorite, biotite granodiorite and biotite granite by fractional crystallization of magma.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.857-858
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• 2008

This paper proposes a new fast algorithm that detects the lanes on the road using Moore-Neighbor edge trace algorithm, which traces the edge elements by searching the connectivity in eight direction window. The detected line components are connected if they have the same orientation on the same line. The proposed algorithm is faster than other conventional algorithms since it tests only the connectivities of the line segments. The performance of the proposed algorithm has tested by the experiments to test how fast and accurate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.851-859
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• 1997

This study was perfomed to investigate the contamination level of harmful heavy metals and the level of trace elements in 15 kinds of fish collected at the western coast in Korea from July to December in 1996. The levels of total lead, cadmium, mercury, iron, copper and zinc were determined and the results were summarized as follows: The minimum and maximum values(ppm) of fish, mean value bracketed, were ; Pb : 0.02~4.80(2.26), Cd: 0.001~0.54(0.04), Hg: 0.007~1.08(0.52), Fe: 7.76~66.39(25.70), Cu; 0.37~121.6(1.90), Zn:12.01~112.10(54.78). The results show that mean contents of Pb, Cd and Hg in 15 species fish were not yet dangerous levels enough to cause a health problem. But the contents of Pb and Hg tend to increase.

• Environmental Analysis Health and Toxicology
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• v.17 no.1
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• pp.21-27
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• 2002

In order to study the relationships between trace element concentrations of hair and internal organs, autopsy samples of hair, liver, kidney cortex, kidney medulla, heart, lung, spleen, cerebrum, testis and bone from 162 Korean subjects were analyzed for Cd, Hg, Pb and Zn by inductively coupled plasma atomic emission spectrometry. High significant positive correlations were found between the Cd concentration in hair and bone and Pb in hair and lung. Hair Hg levels were highly significantly correlated with organ Hg levels in the liver, kidney cortex, kidney medulla, heart, lung, spleen, cerebrum, testis and bone. And hair Zn levels were highly significantly correlated with organ Zn levels in the kidney cortex, kidney medulla, spleen, testis and bone.

• Environmental Analysis Health and Toxicology
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• v.12 no.3_4
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• pp.67-73
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• 1997

This study was carried out to investigate the contents of heavy metals such as iron, copper, lead, cadmium, magnesium, platium in connection with water pollution in sea weed (dried laver) collected from the west, south, south- west, and east coasts of Korea. The results of the study are as follows; Iron was shown the highest value (1.280ppm) in the wild laver from the south coast. Copper was detected in larger qauntities (0.169 ppm) in green laver than in any other kinds of laver observed in this study. Lead was detected in larger quantities (0.195ppm) in the usual laver and green laver from the south-west coast as compared with the other coasts. Although cadmium and platium was also detected from every kind of laver, the concentrations were not over the allowance of the residual.

• Journal of environmental and Sanitary engineering
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• v.4 no.2 s.7
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• pp.101-107
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• 1989

In order to investigate harmful trace in commercial teaproducts. The contents of copper, lead, cadmium, zinc, chromium, manganese and iron were studied in this paper. The samples studied were Youlmoo tea(7) Arrow root tea(9) Ginger tea(4) collected from markets in Seoul area and analysis of seven metals by means of Automic absorption spectrometry. The results obtained were as follows : Lead contents is ranged from 0.06 to 0.72 ppm, cadmium from ND to 0.17 ppm, copper from 0.8 to 16.7 ppm, zinc from 10.4 to 40.4 ppm, manganess from 2.7 to 16.5 ppm, chromium from 0.04 to 4.7 ppm, iron from 7.9 to 55.7 ppm.

• Nuclear Engineering and Technology
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• v.37 no.5
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• pp.503-510
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• 2005

An instrumental neutron activation analysis was used to measure the concentrations of about 24 elements associated with airborne particulates (PM10) that were collected in the most polluted urban region of Daejeon city, Korea from 2000 to 2002. Using the measurement data for various elements, both the extent of elemental pollution in the study area and the seasonality in their distribution characteristics were examined. Examinations of their distribution patterns indicated that most elements with crustal origin tend to exhibit seasonal peaks during spring, while most elements with anthropogenic origin tend to exhibit seasonal peaks during fall or winter. In order to explain the factors regulating their mobilization properties, the data were processed by a factor analysis. Results of the factor analysis suggested competing roles of both industrial and natural source processes, despite that the study site is located at a downwind position of the industrial complex. Based on the overall results of this study, it is concluded that the site may be strongly impacted by man-made sources but the general patterns of elemental distributions in the study area inspected over a seasonal scale are quite consistent with those typically observed from natural environment.

• Computers and Concrete
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• v.19 no.2
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• pp.191-201
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• 2017

External pre-stressing is often used in strengthening or retrofitting of steel-concrete composite beams. In this way, a proper numerical model should be able to trace the completely nonlinear response of these structures at service and ultimate loads. A three dimensional finite element model based on shell elements for representing the concrete slab and the steel beam are used in this work. Partial interaction at the slab-beam interface can be taken into account by using special beam-column elements as shear connectors. External pre-stressed tendons are modeled by using one-dimensional catenary elements. Contact elements are included in the analysis to represent the slipping at the tendon-deviator locations. Validation of the numerical model is established by simulating seven pre-stressed steel-concrete composite beams with experimental results. The model predictions agree well with the experimental results in terms of collapse loads, path failures and cracking lengths at negative moment regions due to service loads. Finally, the accuracy of some simplified formulas found in the specialized literature to predict cracking lengths at interior supports at service loading and for the evaluation of ultimate bending moments is also examined in this work.