• Journal of the Korean Chemical Society
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• v.61 no.6
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• pp.369-377
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• 2017

The purpose of this study was to investigate high school students' perceptions on chemistry subjects: reasons for choosing chemistry, learning volume and content difficulty, interests, teaching/learning methods, preferable classes etc. A total of 1,087 students who took chemistry subjects at 126 high schools by proportional stratified sampling were voluntarily participated in the survey. The main reasons the students chose chemistry subjects were interests and interests in chemistry, foundation to science, relevance to college majors, and so on. Students recognized that the learning volume and content difficulty as normal level was about 60%. Reasons why chemistry was difficult was that, although there was a difference in degree, chemistry was difficult in itself and had too much things to memorize. In the case of interests in chemistry subjects, students of 43.9% of Chemistry I and 52.0% of Chemistry II recognized the level as normal. The reason why not interested in chemistry subjects was that it was the nature of chemistry contents, or students had neither interests and enjoyment of chemistry nor foundation for chemistry. Classes were mostly lectures but the students preferred mainly experimental activities, or explanation with real-life examples or science stories. The frequency of experimental activities was found to be 1 to 5 times per semester, or not experimented. Research and efforts will be necessary to improve classes and environments for students' experimental activities.

• Clean Technology
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• v.20 no.4
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• pp.398-405
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• 2014

In the treatment of spent high energetic materials, the issues such as environmental pollution, safety as well as working capacity should be carefully considered and well examined. In this regard, incineration has been recommended as one of the most promising processes for the disposal of such explosives. Due to the fact that high energetic materials encompass various types and their different characteristics, the technology development dealing with various materials is not an easy task. In this study, rigorous modeling and dynamic simulation was carried out to predict dynamic physico-chemical phenomena for research department explosive (RDX). Plug flow reactor was employed to describe the incinerator with 263 elementary reactions and 43 chemical species. Simulation results showed that safe operations can be achieved mainly by controlling the reactor temperature. At 1,200 K, only thermal decomposition (combustion) occurred, whereas increasing temperature to 1,300 K, caused the reaction rates to increase drastically, which led to ignition. The temperature further increased to 3,000 K which was the maximum temperature recorded for the entire process. Case studies for different operating temperatures were also executed and it was concluded that the modeling approach and simulation results will serve as a basis for the effective design and operation of RDX incinerator.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.6
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• pp.485-493
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• 2017

In this study, the collision analysis of SCP(Sandwich Concrete Panel) composing the outer tank of LNG storage was performed and its collision behavior was analyzed. For the same collision energy value proposed in BS7777 code, the collision conditions are composed by using two types of missiles and various collision speeds. Nonlinear dynamic analysis models were constructed to perform numerical analysis on the various collision conditions. Also, the collision behavior was analyzed assuming that the second collision with the same collision energy occurs at the same point after the first collision. As a result of the analysis, it was found that with smaller missile and low collision speed had caused larger deformation. The collision energy dissipated in ratio of about 6: 4 in the outer steel plate and the inner filling concrete. In the results of double collision analysis, the final collisional deformation was dominated by the size of the second missile, and the amount of deformation due to the second collision was smaller than that of the first collision because of the membrane behavior of the steel plates. In the offset double collision cases, the largest deformation occurs at the secondary collision point regardless of the offset distance.

• Management & Information Systems Review
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• v.39 no.3
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• pp.99-125
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• 2020

This study analyzes the priority according to the importance of the government's oyster industry support policy using AHP (analytic hierarchy process), and it compares and confirms the satisfaction level of direct and indirect workers using this policy in contribution to the development of the oyster industry. The results of the importance analysis by AHP analysis are as follows: As a result of the evaluation of the importance of the entire sample, it is found that the most important factor is the production facilities of the production supply of the competitiveness enhancement, the purchase of raw materials of the production supply of the competitiveness enhancement, and the aging of the structural risks of risk reduction. Also, significant differences among the workers in the ranking of importance are identified. According to the comprehensive evaluation results of indirect workers, which consist of public officials, the National Federation of Fisheries Cooperatives, and related professors, raw materials, production facilities, and high-quality products are produced in order to increase competitiveness. There are differences among workers in order of marine pollution of environmental risks, structural fish population reduction, and structural aging of risk factors.

• Journal of the Korean Dietetic Association
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• v.10 no.1
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• pp.13-24
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• 2004

This study was designed to examine fast food consumption, nutritional knowledge, food behavior and dietary intake of university students and to investigate if there were differences in these variables by fast food consumption. The questionnaire was administered to university students in Daejeon. Data(n=269) was analyzed using $x^2$-test and analysis of variance. Subjects were mostly female(62%) and freshmen or sophomores(86%). Based on the frequency of fast food consumption, subjects were categorized into non-users(27.9%), users(<2 times/week, 42%) and frequent users($\geq$2 times/week, 30.1%). Those who used fast foods(n=194) consumed the foods 7.5 times per month, on the average. Subjects scored 15.6 out of 20 on a nutritional knowledge scale, showing the moderate level of knowledge. When examined by fast food use, the nutritional knowledge score was 15.5 for non-users, 16.1 for users, and 15.0 for frequent-users(p<0.05). Only two items, regarding 'fat type(animal, plant) and health' and 'importance of having breakfast', were significantly different by fast food consumption, with user group and non-users scoring higher than frequent-users(p<0.05). Food behaviors, measured by 20 items, were not desirable, with mean scores of 51.5(possible score: 20-100). Subjects showed problems in eating meals regularly, eating a variety of foods, eating breakfast, and consumption of some food groups(vegetables, fruits, and proteins). Fast food non-users showed more desirable food behaviors than users or frequent-users, such as having processed foods (p<0.001) and eating-out less frequently(p<0.01). Dietary intake data showed that some nutrient intakes, including energy, calcium, iron, zinc and folic acid were less than 75% of the RDA. Index of nutritional quality(INQ) was adequate except for calcium and zinc. Compared to non-users or user group, frequent-users of fast foods consumed higher amounts of lipids(p<0.05), and had lower INQ for calcium(p<0.01). This study described the status of fast food consumption, nutritional knowledge, food behavior of university students, and provided some baseline data for planning nutrition education for university students.

• Korean Journal of Environment and Ecology
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• v.19 no.2
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• pp.150-161
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• 2005

Soraksan National Park and Odaesan National Park, that are 20.7 km apart, should play an important role as habitats and corridors for wildlife because they are located in the center of Baekdudaegan. However, landscape features such as small area, fragmentation, and geographic isolation seem to impede the proper ecological functions of these two national parks. Using GIS technique, we examined the pattern of fragmentation in these two national parks and adjacent regions (Sokcho-si, Goseong-gun, Inje-gun, Yangyang-gun, and Hongcheon-gun) encompassing a total of $4573.5km^2$ in area. We then selected the patches suitable for an endangered carnivorous species, leopard cat, based on habitat conditions, and identified the network and stepping stone among patches to enable leopard cats to migrate. Diverse roads and artificial facilities in the study area generated a total of 24,701 patches: 39 patches among these were selected as potential habitats upon considering the habitat condition such as vegetation types and minimum area for leopard cat. Three patches nearby Gyebangsan and Bangtaesan were identified as a potential network center to relieve the effects of fragmentation and isolation of the two national parks. Our results also showed that patches containing Jombongsan and Bangtaesan would act as a source patch from there leopard cats can disperse to both national parks. It is an urgent task to identify the pattern of fragmentation and the connectivity between patches in national parks and adjacent areas for wildlife conservation because almost all national parks confront land- scape problems similar to the two national parks examined in this study.

• Korean Journal of Environment and Ecology
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• v.21 no.3
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• pp.278-289
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• 2007

This study investigated species formation and their vegetation on the roadsides of 1100 Road and 5 16 Road in Hallasan National Park from August 2004 to December 2006 to provide basic data for distributional attribute of the naturalized plants. The vascular plants investigated on the roadsides of Hallasan National Park were found to be 62 families, 145 genera, 197 taxa in total, in which naturalized plants were recorded as 11 families, 29 genera, and 37 taxa. The floristic formation at 1100 Roadside was composed of Festuca arundinacea-Dactylis glomerata association, which was again divided into Trifolium pratense-Plantago lanceolata sub-association and Sasa quelpaertensis-Gleichenia japonica sub-association. The florisitic composition of the 5 16 Roadside was sorted as Festuca arundinacea-Dactylis glomerata association, Oplismenus undulatifolius-Potentilla fragarisiiforlia, elatior association, Ambrosia artemisiifolia, and etatior-Persicaria thunbergii association. Among the naturalized plants distributed at this area, the annual plant accounts for 51.4%[19 taxa] and the plant of European origin accounts for 70.3%[26 taxa]. As for the background of the introduction of these plants, the case of introduction for forage or a mixture with grain and for pasture was 35.1% and 21.6% respectively, showing higher introduction circumstances than others. As shown in the study, most of the roadsides were occupied by the naturalized plants- Festuca arundinacea and Dactylis glomerata association and various naturalized plants; thus we can assume that it's because Festuca arundinacea and Dactylis glomerata association were mostly used for re-vegetation of the destroyed areas due to road construction or expansion or road maintenance and improvement project.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.5
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• pp.65-76
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• 2010

In this paper, earthquake fragility analysis has been comparatively performed with regard to a buried gas pipeline of API X65 which has been widely used in Korea. For this purpose, a nonlinear time-history analyses has been carried out for 15 different analytical models of a buried gas pipeline in terms of the selected 12 sets of earthquake ground motions with 0.1g of scaling interval. Following that, earthquake fragility analyses have been conducted using the maximum axial strain of the pipeline obtained from the nonlinear time-history analyses. Parameters under consideration for subsequent earthquake fragility analyses are soil conditions, end-restraint conditions, burial depth and the type of pipeline. Comparative analyses reveal that whereas the first three parameters influence the fragility curves, particularly soil conditions amongst the three parameters, the last parameter has a little effect on the curves. In all, the present study can be considered as a benchmark fragility analysis of a buried gas pipeline in the absence of an earthquake fragility analysis of the pipeline and thus is expected to be a useful source regarding earthquake fragility analyses of a buried gas pipelines.

• Korean journal of applied entomology
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• v.44 no.2
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• pp.131-137
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• 2005

Seasonal occurrence of the egg parasitoid of bugs, Ooencyrtus nezarae (Hymenoptera: Encyrtidae), was monitored at soybean fields and university campus using traps baited with aggregation pheromone of bean bug, Riptortus clavatus, in Jinju, Gyeongnam province, Korea. The female O. nezarae captured at university campus in 2003 and 2004 was 317.5 and 103.4 times as many as males, respectively, and it was 12.6 times at soybean field in 2004. The female began to occur from late August, showing its peak around September 20 at soybean field in 2004. At university campus in 2003 and 2004, the female began to occur from mid or late August, and showed its peak early or mid September. At the two monitoring sites the catches of female sharply declined after October The E2HZ3H only showed attractiveness to O. nezarae, among three components of the aggregation pheromone of bean bug, (E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H), (E)-2-hexenyl (E)-2-hexenoate (E2HE2H), and myristyl isobutyrate (MI). A mixture in a ratio of 20:20:10 or 16.7:16.7:16.7 of E2HZ3H:E2HE2H:MI attracted significantly more females than the mixture of 7:36:7 ratio did. This higher attractiveness of the former two blends may be attributed to the higher amounts of E2HZ3H in the blends.

• Proceedings of the ESK Conference
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• 1993.10a
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• pp.20-20
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• 1993

반복적인 일의 수행으로 인한 병인 누적외상병에 관해 살펴보고자 한다. 누적외 상병(Cumulative Trauma Disorders)이란 비교적 생소한 질환으로 손이나 어떤 신체 부위를 반복적으로 오래 사용하였을 때 오는 병이다. 이 질환은 200년전 이탈리아 의사인 Benardino Ramazinni에 의해 분류되었으나 최근까지 큰 관심을 끌지 못했 다. 이 병은 Tennis Elbow(테니스 팔꿈치) 또는 Triger Finger(방아쇠 손가락)등 으로 더 잘 알려져 왔다. 그리고 의학계에서는 Ganglions(수종)으로 알려져 왔다. 그러나 80년대의 탁상컴퓨터의 보급으로 많은 사무실에서 반복적인 작업을 연속적 으로 하게 되어 많은 사무원들이 누적외상병(CTD)으로 고통에 시달리게 되고, 심한 경우에는 수술까지 하게된다. 제안자 역시 이 병으로 손목수술을 받은 바 있는 데 이 병은 잠복기가 몇년씩 되는 직업병이다. 이병의 특성상 암과 같이 조기에 발견 하기 어렵고, 이것을 느꼈을 때는 대부분 너무 늦어 수술이 불가피한 경우가 많다. 본 연구에서는 누적외상병의 실체와 현재까지의 외국에서 수행된 연구결과를 소개하고, 현재 한국에서의 이병의 실태를 파악하기 위해 표본대상을 선정하여 설 문조사와 실측조사를 함께 수행하고자 한다. 표본대상으로 육체노동으로 반복작업 을 하는 (Blue-Color) 집단, 사무실에서 반복작업을 하는 (White-Color) 집단, 그리 고 가정에서 반복작업을 하게 되는 주부집단등으로 나누어 실태조사를 하고자 한다. 설문조사의 통계처리를 바탕으로 한국에서의 누적외상병에 관한 실태조사와 의식구 조까지를 진단해 보고자 한다. 그런 다음 총체적이고 최신의 이론과 연구에 바탕을 둔 해결책과 대안을 제시해 보고자 한다.콘에 대해 일반화시키기는 어려우나 이후에 행해질 Icon-based User Interface 분야의 많은 연구들의 기초가 될 것이다. 더불어 아이콘과 관련된 많은 요인들(문화적 영향, 아이콘 색깔, 크기, 아이콘의 위치등이 인식에 미치는 영향)에 대해서도 연구가 행해져야 할 것이다. 확인하고 각각의 기능을 분명히 했다.가 수월하게 하였고 메모리를 동적으로 관리할 수 있게 하였다. 또한 기존의 smpl에 디버깅용 함수 및 설비(facility) 제어용 함수를 추가하여 시뮬레이션 프로그램 작성을 용이하게 하였다. 예를 들면 who_server(), who_queue(), pop_Q(), push_Q(), pop_server(), push_server(), we(), wf(), printfct() 같은 함수들이다. 또한 동시에 발생되는 사건들의 순서를 조종하기 위해, 동시에 발생할 수 있는 각각의 사건에 우선순위를 두어 이 우선 순위에 의하여 사건 리스트(event list)에서 자동적으로 사건들의 순서가 결정되도록 확장하였으며, 설비 제어방식에 있어서도 FIFO, LIFO, 우선 순위 방식등을 선택할 수 있도록 확장하였다. SIMPLE는 자료구조 및 프로그램이 공개되어 있으므로 프로그래머가 원하는 기능을 쉽게 추가할 수 있는 장점도 있다. 아울러 SMPLE에서 새로이 추가된 자료구조와 함수 및 설비제어 방식등을 활용하여 실제 중형급 시스템에 대한 시뮬레이션 구현과 시스템 분석의 예를 보인다._3$", chain segment, with the activation energy of carriers from the shallow trap with 0.4[eV], in he amorphous regions.의 증발산율은 우기의 기상자료를 이용하