• Journal of Welding and Joining
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• 제23권3호
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• pp.76-82
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• 2005

Recently the application of laser welding technology has been considered to shipbuilding structure. However, when this technology is applied to primer coated steel, good quality weld beads are not easily obtained. Because the primer-coated layer caused the spatter, humping bead and porosity which are main part of the welding defect attributed to the powerful vaporizing pressure of zinc. So we performed experiment with objectives of understanding spatter and porosity formation mechanism and producing sound weld beads in 6mmt primer coated steels by a $CO_2$ CW laser. The effects of welding parameters; defocused distance, welding speed, coated thickness and coated position; were investigated in the bead shape and penetration depth on bead and lap welding. Alternative idea was suggested to suspend the welding defect by giving a reasonable gap clearance for primer coated thickness. The zinc of primer has a boiling point that is lower than melting point of steel. Zinc vapor builds up at the interface between the two sheets and this tends to deteriorate the quality of the weld by ejecting weld material from lap position or leaving porosity. Significant effects of primer coated position was lap side rather than surface. Therefore introducing a small gap clearance in the lap position, the zinc vapor could escape through it and sound weld beads can be acquired. In conclusion, formation and suspension mechanism of the welding defects was suggested by controling the factors.

• 아동학회지
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• 제5권
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• pp.21-45
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• 1984

The cognition of Korean kinship names was examined in children in the 1st, 3rd, 5th, and 9th grades (N=188) of public school. The task consisted of 43 items which identified the relative relationships of cognates and cognates-in-law. It was found that the main effects of age and residential area on cognition scores were significant and the interaction effects between the variables were also significant. As expected, older children performed the task more precisely than the younger children and children in Seoul performed better than in outlying regions. Under 15 years of age, the scores in Seoul were higher than in Andong, but at the age of l5, this trend was reversed. The gap between residential areas under 15 years of age could be explained by differences in cognitive ability and test effects, but the gap at 15 by culture.

• Journal of Korean Vacuum Science & Technology
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• 제4권1호
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• pp.27-32
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• 2000

We have studied the carrier relaxation of InAs/GaAs modulation-doped quantum dots depending on the excitation wavelength and modulation-doping concentration by using the time-ressolved spectroscopy. At the excitation below GaAs barrier band gap, the relaxation processes become very slow, implying to observe the phonon bottleneck effects. On the other hand, at the excitation far above GaAs band gap, phonon bottleneck effects are broken down due to Auger processes. Increasing modulation-doping concentration, the relaxation times, by virtue of Coulomb scattering between electrons in GaAs doped layer and carriers in InAs quantum dots, are observed to become fast.

• Nuclear Engineering and Technology
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• 제41권3호
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• pp.271-278
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• 2009

Nucleate pool boiling of water in vertical annuli at atmospheric pressure has been studied experimentally and two empirical correlations have been suggested to obtain effects of geometric parameters on heat transfer. Data of the present and the previous tests range over a tube length of 0.50-0.57 m, a diameter of 16.5-34.0 mm, and an annular gap size of 3.7-44.3 mm. Through the analysis, tube bottom confinement (open or closed) has been investigated, as well. The developed correlations predict experimental data within a ${\pm}25%$ error bound. It has been identified that effects of the diameter and the length of heated tubes as well as the annular gap size should be counted into the analyses to estimate heat transfer coefficients accurately.

• 콘크리트학회논문집
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• 제17권4호
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• pp.631-635
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• 2005

Aggregate gradation effects on cracking-related displacements of concrete are investigated in the laboratory using the German cracking frame. Concrete workability was assessed by use of the slump and drop tests for two different concrete mixtures consisting of gap-graded and dense-graded aggregates. Shrinkage strain, cracking frame strain, and concrete strain were measured and used to compare to strength gain and creep development. The measured and calculated strains of the different aggregate gradations were compared each other. Gradation effects on strength and stress development relative to tensile cracking at saw-cut tip were also investigated. Test results revealed that the gap-graded concrete has indicated larger shrinkage and creep strains than dense-grade concrete perhaps because of its higher volume concrete of cement mortars in the mixture.

• Toxicological Research
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• 제17권
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• pp.227-236
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• 2001

The IARC Monographs Programme on the Evaluation of Carcinogenic Risks to Humans has reviewed, summarized and evaluated 869 environmental agents and exposures as oj June 2000. This large collection includes all relevant published epidemiological data on cancer in exposed humans and results of bioassays for carcinogenicity in experimental animals. Since 1986. cancer data have been systematically supplemented by summaries of other toxicological data that are relevant to assessments of carcinogenic hazard. These include summaries qf genetic and related effects of chemicals. which have been prepared as Genetic Activity Profiles (GAP) by the U.S. EPA in collaboration with IARC. As the Mono-graphs have proved increasingly valuable and influential worldwide. they have evolved into an encyclopedia on environmental carcinogenic risks to humans. However. the Monographs have historically been prepared only as printed books with limited distribution. and the Monographs Programme has needed to adjust to expectations oj wider availability. Since 1998 the evaluations and summaries have been globally accessible by Internet from IARC (http://www.iarc.fr) and the GAP profiles by Internet from EPA (http://www.epa.gov/gapdb/). with the two web sites linked. Improved EPN/ARC GAP database and software. GAP2000. now link GAP profiles directly to the appropriate IARC web pages for summaries of evaluations of a given compound and its overall IARC classification. During the year 2000. by means of optical character recognition (OCR) technology the entire series of IARC Monographs is being converted to an electronic version. The first edition is now available commercially in CD-ROM format and will soon become available on-line at .

• Journal of Korean Neurosurgical Society
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• 제49권1호
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• pp.13-19
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• 2011

Objective: The purpose of this study is to investigate the combined effects of ginkgo biloba extract, ginkgolide A and B and aspirin on SK-N-MC, human neuroblastoma cell viability and mRNA expression of growth associated protein43 (GAP43), Microtubule-associated protein 2 (MAP2), B-cell lymphoma2 (Bcl2) and protein53 (p53) gene in hypoxia and reperfusion condition. Methods: SK-N-MC cells were cultured with Dulbecco's Modified Eagle's Medium (DMEM) media in $37^{\circ}C$, 5% $CO_2$ incubator. The cells were cultured for 8 hours in non-glucose media and hypoxic condition and for 12 hours in normal media and $O_2$ concentration. Cell survival rate was measured with Cell Counting Kit-8 (CCK-8) reagent assay. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to estimate mRNA levels of GAP43, MAP2, Bcl2, and p53 genes. Results: The ginkgolide A and B increased viable cell number decreased in hypoxic and reperfused condition. The co-treatment of ginkgolide B with aspirin also increased the number of viable cells, however, there was no additive effect. Although there was no increase of mRNA expression of GAP43, MAP2, and Bcl2 in SK-N-MC cells with individual treatment of ginkgolide A, B or aspirin in hypoxic and reperfused condition, the co-treatment of ginkgolide A or B with aspirin significantly increased GAP43 and Bcl2 mRNA levels. In MAP2, only the co-treatment of ginkgolide A and aspirin showed increasing effect. The mRNA expression of p53 had no change in all treating conditions. Conclusion: This study suggests that the combined treatments of Ginkgo biloba extracts and aspirin increase the regeneration of neuroblastoma cells injured by hypoxia and reperfusion.

• 사회복지연구
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• 제48권3호
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• pp.145-169
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• 2017

신 사회위험의 하나의 축은 가족 구조의 재편과 여성의 경제활동참여율 증가에 따라 발생한 새로운 욕구들이다. 일가정양립정책이 여성 경제활동에 미치는 영향에 대한 연구는 활발하게 이루어지고 있음에도 불구하고, 여성 취업에 영향을 미칠 수 있는 제도로서 생산레짐의 함의를 살펴보는 연구는 미진한 실정이다. 본 연구는 룩셈부르크 소득연구(Luxembourg Income Study) 자료를 이용하여 생산레짐과 일가정양립정책이 성별 임금격차에 미치는 영향을 분석하였다. 분석결과, 기업특정적 기술 활용이 활발한 조정경제시장에서 여성의 임금이 남성에 비해 통계적으로 유의하게 낮게 나타나 성별 임금격차가 증가하는 것으로 나타났다. 반면, 육아휴직과 보육지출은 여성의 임금순위를 향상시키는 것으로 나타나 성별 임금순위격차를 약화시키는 것으로 분석되었다. 본 연구는 제도적 측면에서 생산레짐과 일가정양립정책이 여성의 임금순위에 미치는 영향을 실증적으로 평가했다는 데 그 의의가 있다.

• 한국대기환경학회지
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• 제13권3호
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• pp.207-214
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• 1997

We collected airborne complex mixtures in a industrial area of Yeochun, and examined whether these complex mixtures could affect gap junctional intercellular communication (GJIC) in a cultured WBF-344 rat liver epithelial cells (LEC). Since the reduction of GJIC plays an important role in chemical carcinogenesis, measurement of changes of GJIC is a meaningful method to screen carcinogenicity of these mixtures. High and low volume samples were dissolved in dimethyl sulfoxide (DMSO) and tested. Blank filter extractions were also examined for exclud-ing possible toxicity of filter itself, and TPA (12-O-tetradecanoylphorbol-13-acetate) and DMSO were used as positive and negative control, respectively. When the cells were exposed to samples at concentration below that required to maintain rather than 85% cell viability based on the result of neutral red uptake assay, maximal inhibition of GJIC was observed at 1hr after treatment with both high and low volume samples by scrape-loading dye transfer assay. In fluorescence recovery after photobleaching assay, recovery rates via gap junctions were 33%/min in high volume sample and 62%/min in low volume sample. In together, airborne samples collected in Yeochun inhibited GJIC in a cultured WBF-344 rat LEC. These results suggest airborne samples tested in this experiment may attribute to cause a certain type and degree of cancers in in vivo when exposured for some periods.

• 유통과학연구
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• 제15권1호
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• pp.51-56
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• 2017

Purpose - The study verified the effects of consumers' knowledge perception upon word-of-mouth intention and purchase intention of consumers who were exposed to a lot of information, and examined consumer's behavior from multi-dimensional points of view. Research design, data, and methodology - The study conducted the test of difference between consumer's cognition on importance and satisfaction of HMR product by gap of HMR (Home Meal Replacement) product for IPA analysis. The consumer's reliability and words-of-mouth were measured by the questionnaire method with 4 questions according to Likert 7-point scale. Conversion into z-score removed the difference of variables. Results - The causal relation model for importance, satisfaction and gap, not relying upon multi-dimensional scaling and others, could construct causal relation model to give implications. Difference (d) of the products could lessen consumer's reliability to increase consumer's knowledge perception, word-of-mouth intention, knowledge perception, and purchase intention. Therefore, enterprises should make an effort to lessen consumers' complaint for the products and to elevate consumers' reliability. Enterprises also try to give consumers exact information and to promote purchase intention. Conclusions - Difference (d) of consumers' complaint and/or disappointment decreased consumers' reliability to increase knowledge perception. Enterprises should supply consumers with products according to their requirements to minimize the gap and to give them proper information.