• Journal of the korean society of oceanography
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• 제35권1호
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• pp.16-33
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• 2000

In order to measure the vertical fluxes of particles and reactive radionuclides such as thorium and polonium isotopes, Dunbar-type sediment traps were freely deployed at the Ulleung Basin and in warm and cold water masses around the polar front of the East Sea. We estimated the ratios of the catched (F) to the predicted $^234$Th fluxes (P) using natural tracers pair $^234$Th-$^238$U. The F/P ratios are decreased with increasing water depth. Whereas the concentrations of suspended particles are homogeneous in water column, the mass fluxes are also decreased with increasing water depth like the F/P ratios. These facts indicate that organic matters of settling particles are destructed within the euphotic layer due to decomposition. Whereas regenerations of sinking particles are negligible in the cold water mass, about 80% of them are regenerated in the warm water mass during falling of large particles. These downward mass fluxes are closely correlated with their primary productions in euphotic zone. The activities of $^234$Th, $^228$Th and $^210$Po in the sinking material were increased with water depth. Because $^234$Th steadily produced in the water column are cumulatively adsorbed on the surface of sinking particles, vertical $^234$Th fluxes were observed to increase with water depth. Therefore, these sinking particles play important roles in transporting the particle reactive elements like thorium from surface to the deep sea. The scavenging processes including adsorption and settling reactions generate radio-disequilibrium between daughter and parent nuclides in water column. The activity ratios of $^234$Th/$^238$U and $^228$Th/$^228$Ra were observed to be < 1.0 in the surface water and approached to be equilibrium below the thermocline. The extent of the deficiency of daughter nuclides compared to the parents nuclide was highly correlated with the vertical particle flux. Because most of the $^210$Po in the surface water are scavenged on a labile phase and are recycled at sub-surface depths (< 200 m), the $^210$Po are always observed to be excess activities compared to $^226$Ra in surface water.

• Journal of Ecology and Environment
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• 제41권1호
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• pp.19-28
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• 2017

Background: In order to investigate organic carbon distribution, carbon budget, and cycling of the subalpine forest, we studied biomass, organic carbon distribution, litter production, forest floor litter, accumulated soil organic carbon, and soil respiration in Taxus cuspidata forest in Halla National Park from February 2012 to November 2013. Biomass was calculated by using allometric equation and the value was converted to $CO_2$ stocks. Results: The amount of plant organic carbon was $13.60ton\;C\;ha^{-1}year^{-1}$ in 2012 and $14.29ton\;C\;ha^{-1}year^{-1}$ in 2013. And average organic carbon introduced to forest floor through litter production was $0.71ton\;C\;ha^{-1}year^{-1}$. Organic carbon distributed in forest floor litter layer was $0.73ton\;C\;ha^{-1}year^{-1}$ on average and accumulated organic carbon in soil was $51.13ton\;C\;ha^{-1}year^{-1}$ on average. In 2012, Amount of released $CO_2$ from soil to atmosphere was 10.93 ton $CO_2ha^{-1}year^{-1}$. Conclusions: The net ecosystem production based on the difference between net primary production of organic carbon and soil respiration was $-1.74ton\;C\;ha^{-1}year^{-1}$ releasing more carbon than it absorbed.

• 한국의류산업학회지
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• 제7권3호
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• pp.291-300
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• 2005

The purpose of this study is to investigate, analyze the purchasing behavior of fashion goods according to life style and role model of preteen generation, and provide manager or marketing planner for the reference data so that they can understand preteen generation and make proper strategy efficiently. So called, preteen market focusing on 1014 generation (from ten to fourteen years old) is highlighted. This generation created between the year 1989 to 1993 after Seoul Olympic monopolize parent's love in abundant economic environment and rise to the core of consumption subject. Products aiming at this preteen generation continuously though consumption mind was shrunk greatly due to recession. Only 2~3 years before preteen market was regarded as grey zone which doesn't belong to not only children (between six and nine years old) but also teenagers (between fifteen to eighteen years old). But in recent day their purchasing powers have increased rapidly and age group is divided on details, so that preteen market has become a niche market. Subjects were 333 persons consisting of students in the 4th~6th grade of primary school and the 1st~2nd grade of middle school in Daegu city. Measuring instruments are as follows: 5questions to differentiate preteen generation, 22 questions to measure life style, 17questions (which have six sub-factors such as purchase motive, factor of product selection, utilization of informant, purchase time, purchase place, and purchase method) to measure the purchase behavior of fashion goods measurement, and 16 questions (which have four sub-factors such as parent, entertainer & sports stars, brothers and sisters, friends) to measure model of role. Statistical data were processed by SPSS 10.0 programs. Frequencies, Factor analysis, Cluster analysis, ANOVA, Cross analysis, Multiplex regression analysis, and Duncan's multiple range test were carried out.

• Preventive Nutrition and Food Science
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• 제20권2호
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• pp.126-132
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• 2015

This study investigated the anti-amnesic effect of fermented Ganoderma lucidum water extracts (GW) on scopolamine- induced memory impairment in rats. GW were fermented by the lactic acid bacterium Bifidobacterium bifidum (FGWB), followed by Lactobacillus sakei LI033 (FGWBL). To induce amnesia, scopolamine (1 mg/kg) was intraperitoneally injected into rats 30 min before the behavioral tests. Step-through latencies of rats treated with primary fermented extracts (300 mg/kg, FGWB) and secondary fermented extracts (300 mg/kg, FGWBL) were significantly longer than those of rats treated with GW (300 mg/kg) in the retention trial of the multiple trial passive avoidance test. In the Morris water maze task, FGWBL significantly shortened escape latencies in training trials. Furthermore, swimming times within the target zone during the probe trial with FGWBL were significantly higher than the GW and FGWB treatments. In addition, acetylcholinesterase activities were lower in the brains of scopolamine-treated rats treated with FGWBL. These results suggest that FGWBL could be useful to enhance learning memory and cognitive function via cholinergic dysfunction.

• 대한기계학회논문집A
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• 제20권9호
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• pp.2894-2900
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• 1996

The stream generator tubes represent an integral part of a major barrier against the fission product release to the environment. So, the rupture of these tubes could permit flow of reactor coolant into the secondary system and injure the safety of reactor coolant system. Therefore, if the crack was detected during In-Service Inspection of tubes the cracked tube should be evaluated by the pulgging criteria and plugged or not. In this study, the fracture mechanics evaluation is carried out on the thru-wall axial crack due to Primary Water Stress Corrosion Cracking in the roll transition aone of steam generator tube to help the assurence the integrity of tubes and estabilish the plugging criteria. Due to the Inconel which is used as tube material is more ductile than others, the plastic instability repture theory was used to calculate the critical and allowable crack length. Based on Leak Before Break concept the leak rate for the critical crack length and the allowable leak rate are compared and the safety of tubes was given.

• Parasites, Hosts and Diseases
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• 제50권4호
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• pp.379-384
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• 2012

Resistance of Plasmodium spp. to anti-malarial drugs is the primary obstacle in the fight against malaria, and molecular markers for the drug resistance have been applied as an adjunct in the surveillance of the resistance. In this study, we investigated the prevalence of mutations in pvmdr1, pvcrt-o, pvdhfr, and pvdhps genes in temperate-zone P. vivax parasites from central China. A total of 26 isolates were selected, including 8 which were previously shown to have a lower susceptibility to chloroquine in vitro. For pvmdr1, pvcrt-o, and pvdhps genes, no resistance-conferring mutations were discovered. However, a highly prevalent (69.2%), single-point mutation (S117N) was found in pvdhfr gene. In addition, tandem repeat polymorphisms existed in pvdhfr and pvdhps genes, which warranted further studies in relation to the parasite resistance to antifolate drugs. The study further suggests that P. vivax populations in central China may still be relatively susceptible to chloroquine and sulfadoxine-pyrimethamine.

• 한국정밀공학회지
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• 제6권1호
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• pp.45-51
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• 1989

In metal cutting various types of chips are produced in consequence of cutting conditions. According to the type of chips the cutting mechanism is to be changed. Most of the cutting theory is based on the continuous chip because of its convenient analysis, but the occurrence of the saw-toothed chip depends upon the workpiece and/or the cutting conditions, one of which is titanium alloy used widely. Nowadays titanium alloys are used widely with the rapid development of aerospace structural engineering application, whereas the theory of cutting mechanism has not been established yet, and the formatting process has not been understood satisfactorily, either. Unfortunately several misconceptions, conflicting statements and statements needing further clarifi- cation are also found. In this paper an attempt is made to clarify the formation process of saw-toothed chips which are to be produced during the orthogonal cutting process of titanium alloys. They were machined at low speed to avoid the rapid tool wear. We observed the SEM-photographs of chips taken at the quick-st- opping device. It is hoped that a rational model of the mechanics of cyclic chip formation can be developed. The results obtained are as follows. 1. When a saw- toothed chip is formed, the shear band begins at the primary shear zone and trans- fers to the free surface, so that a segment is produced and it is completed by upsetting between the formatting segment and the formatted segment. 2. As the rake angle or the clearance angle increases in the machining of the titanium alloy, the chip approaches to that of the continous type. 3. When the rake angle and the clearance angle are increased the shear energy and the unit friction energy decrease, which shows the same aspect as that of the continuous chip.

• 한국지역지리학회지
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• 제9권3호
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• pp.395-409
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• 2003

본 연구에서는 세계화의 조류 속에서 지역화의 조류도 명확하게 나타나고 있는 현실을 지리교육에 반영하고자 국가 교육과정의 운영과 편성의 자율화에 대한 의미와 필요성을 살펴보았다. 국가 교육과정의 자율화와 지리교육의 지역화에 따른 새로운 지리교육 학습내용 선정과 구성 및 교수 학습을 하기 위한 사례지역으로서 화천지역을 대상으로 적용해 보았다. 지리적인 사실을 단순히 학습내용으로 구성하기보다는 지리교육적인 관점에서 학령수준에 맞게 내용을 재구성하여 현재 초 중학교에서 제작 운영하고 있는 지역교과서의 차원에서 지역학습을 해야만 한다. 학습 내용도 일상생활이 이루어지고 있는 학습자들의 생활공간을 대상으로 하여 구성되어야만 하겠다. 아울러 학습 지역의 규모에 따른 교수 학습 방법도 고려되어야 함으로 본 연구에서는 생활권 범위내의 일상적인 사실을 중심으로 한 소규모지역을 학습 내용으로 하였기에 야외조사 학습방법을 중심으로 하였다.

• Applied Microscopy
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• 제48권3호
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• pp.55-61
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• 2018

The synaptic vesicle is a specialized structure in presynaptic terminals that stores various neurotransmitters. The actin filament has been proposed for playing an important role in mobilizing synaptic vesicles. To understand the role of actin filament on synaptic vesicle pooling, we characterized synaptic vesicles and actin filament after treatment of brain-derived neurotrophic factor (BDNF) or Latrunculin A on primary cultured neuron from rat embryo hippocampus. Western blots revealed that BDNF treatment increased the expression of synapsin I protein, but Latrunculin A treatment decreased the synapsin I protein expression. The increased expression of synapsin I after BDNF disappeared by the treatment of Latrunculin A. Three-dimensional (3D) tomography of synapse showed that more synaptic vesicles localized near the active zone and total number of synaptic vesicles increased after treatment of BDNF. But the number of synaptic vesicle was 2.5-fold reduced in presynaptic terminals and the loss of filamentous network was observed after Latrunculin A application. The treatment of Latruculin A after preincubation of BDNF group showed that synaptic vesicle number was similar to that of control group, but filamentous structures were not restored. These data suggest that the actin filament plays a significant role in synaptic vesicles pooling in presynaptic terminals.

• 한국콘텐츠학회논문지
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• 제12권7호
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• pp.453-462
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• 2012

본 연구는 삶의 질에 대해 평가할 수 있는 객관적인 평가지표를 마련하고, 지역별 인구구성에 따른 차별화된 삶의 질 정책 실현을 위한 기초자료를 마련하는데 목적이 있다. 삶의 질 평가지표를 개발하고, 연령별 삶의 질에 대한 가중치 차이가 있는지 분석하기위해, (1) 문헌 및 선행연구를 분석해 1차 평가지표를 선정한다. (2) 전문가 FGI를 실시하여 최종 평가지표를 도출한다. (3) 전문가를 대상으로 가중치 분석을 실시한다. 분석 결과, (1) 영역별 가중치는 가족안전, 경제안정, 주거문화, 보건복지, 교통환경 순서로 나타났다. 특히, 가족안전영역은 다른 분야보다 2배 이상 중요한 것으로 나타났다. (2) 연령별 가중치 분석결과, 연령이 높을수록 경제안정을 중요시하는 반면, 가족안전영역에 대하여는 연령이 많을수록 가중치가 떨어졌다. 소득수준이 높아지면서 1인당 주거면적과 도시공원면적, 전시공연의 중요성이 모든 연령에 걸쳐 주거 환경 문화에 관심이 높아지고 있음을 시사한다.