• 한국수소및신에너지학회논문집
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• 제22권4호
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• pp.534-545
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• 2011

This paper describes the evaluation of kinetic parameters for pyrolysis and carbon char oxidation of residual oil. The non-isothermal pyrolysis of residual oil was carried out with TGA (Thermo-Gravimetric Analyzer) at heating rate of 2, 5, 10 and $20^{\circ}C/min$ up to $800^{\circ}C$ under N2 atmosphere. The first order and nth order pyrolysis models were used to fit the experimental data, and the nth order model was turned out to follow the experimental data more precisely than the first order model. For carbon char oxidation experiment, TGA and four heating rates used in pyrolysis experiment were also adapted. The kinetic parameters for the residual carbon char particle were obtained with three char oxidation model, that is, volume reaction, grain and random pore model. Among them, the random pore model described the char oxidation behaviour quite well, compared to other two models. The non-linear regression method was used to obtain kinetic parameters for both pyrolysis and carbon char oxidation of residual oil.

• 한국환경복원기술학회지
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• 제6권2호
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• pp.78-88
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• 2003

This study was conducted to develop the plant-mat for ecological restoration which was formed as the thin multi-layers of woven nets, soil media, seeds, etc. The experimental site was selected at a slope of 240$m^2$ at the rear of Design College of Sangmyung University and divided into 8 sub-experimental plots (20$m^2$ each) according to mat types. (forest-type and grass-type mats with and without seed attachment, respectively) Also, the existing vegetation plot and the no-treatment plot were included in this experiment for comparison. The experiment construction was conducted on September 3, 2002. Mat covered plots regardless of seed attachment showed nearly no signs of erosion even if rainy season in summer compared to the no-treatment plot. Vegetation monitoring result showed that germination rates were somewhat high in both forest and grass-type mats without seed attachment in the initial germination stage. Although germination rates of seed attached mats were somewhat slower than non-seed attached mats in the germination stage, but over time, it showed a good rooting and shooting environment for germinated tree and grass species because of soil media existence within the mat. This indicates that while non seed-attached mats require follow-up maintenance, seed-attached mats does not require maintenance after rooting and germination.

• Safety and Health at Work
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• 제11권2호
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• pp.207-214
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• 2020

Background: Prolonged sitting at work can lead to adverse health outcomes. The health risk of office workers is an increasing concern for the society and industry, with prolonged sitting work becoming more prevalent. Objective: This study aimed to explore the variation in muscle activities during prolonged sitting work and found out when and how to take a break to mitigate the risk of muscle symptoms. Methods: A preliminary survey was conducted to find out the prevalence of muscle discomfort in sedentary work. Firstly, a 2-h sedentary computer work was designed based on the preliminary study to investigate the variation in muscle activities. Twenty-four participants took part in the electromyography (EMG) measurement study. The EMG variations in the trapezius muscle and latissimus dorsi were investigated. Then the intervention time was determined based on the EMG measurement study. Secondly, 48 participants were divided into six groups to compare the effectiveness of every break type (passive break, active break of changing their posture, and stand and stretch their body with 5 or 10 mins). Finally, data consisting of EMG amplitudes and spectra and subjective assessment of discomfort were analyzed. Results: In the EMG experiment, results from the joint analysis of the spectral and amplitude method showed muscle fatigue after about 40 mins of sedentary work. In the intervention experiment, the results showed that standing and stretching for 5 mins was the most effective break type, and this type of break could keep the muscles' state at a recovery level for about 30-45 mins. Conclusions: This study offers the possibility of being applied to office workers and provides preliminary data support and theoretical exploration for a follow-up early muscle fatigue detection system.

• 한국안전학회지
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• 제5권3호
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• pp.3-7
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• 1990

This study is conducted to experiment on the performance test for 20 types of Filter-integrated Half-masks which could not only protect workers exposed to dusty environment, but also improve workability. Results and conclusions are as follows ： 1) Respirators that removal efficiency of aerosols is 95 percent or more are 11 kinds(55%), and those who are 99.9 percent or more are 4 kinds(20%). Respirators that inhalation resistance is 4 mm in water or less are 13 kinds(65%), and those who are 6 mm in water or less are 17 kinds(85%). Respirators that efficiency of cumulative inhalation resistance is 100 percent or less are 11 kinds(55%) . 2) Respirators that resistance of moisture inhalation is 6 mm in water or less are 11 kinds(55%). and those who are 10 mm in water or less are 13 kinds(65cio), Respira'tors that ratio of removal efficiency for aerosols between dry and wet conditions is 95 percent or more are 9 kinds(45%). 3) Respirators which are not only 95 percent or more for removal efficiency of aersosls and 6 mm in water or less for inhalation resistance, but also 200 percent or less for efficiency of cumulative inhalation resistance, are 8 kinds(40％). Respirators which are not only 99.9 percent or more for removal efficiency and 6 mm in water or less for inhalation resistance, but also 100 percent or less for efficiency of cumulative inhalation resistance, are 3 kinds(15%). Respirators which are not only 95 percent or more for removal efficiency of aerosols and 6 mm in water or less for inhalation resistance, but also 200 percent or less for efficiency of cumulative inhalation resistance and 10 mm in water or less for resistance of moisture inhalation, are 6 kinds(30％) . 4) As standard rrlodel of artificial human head which would be perhaps different from the true one Is used to experiment fitness test, leakage rate is shown to be more or less high. However, artificial human head shall be accurately examined and follow-up studt. would be conducted in the future.

• 대한수학교육학회지:수학교육학연구
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• 제26권3호
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• pp.509-525
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• 2016

수학교사 교육에서는 수학교육의 이론 지도 못지않게 교사의 수업 역량 개발을 위한 교육도 충실하게 이루어져야 한다. 본 연구는 프로이덴탈(Freudenthal), 폴리아(Polya)등 현대 수학교육자들이 주목한 수학 학습 지도의 전형으로서 오늘날 수학 교육에 적지 않은 시사점을 주고 있는 소크라테스(Socrates)의 '산파법'을 주제로 하여 사범대학의 예비교사 교육 과정에서 수학 모의수업 실행을 지도한 것이다. 수학을 지도하는 예비교사들의 수업 실기 능력과 수업 연구 능력을 더욱 강화하기 위해 현직교사들의 활동 자료를 연계한 교육을 실시하였다. 현직교사들의 사고실험 예시를 통해, 예비교사들이 수학-학습 지도에 관한 자신들의 제한된 지식과 경험을 확장할 수 있도록 안내하였다. 좋은 수학 수업을 위한 교사 교육, 반성적 사고를 돕는 교사 교육, 교사 공동체 연구를 보조하는 교사 교육을 꾀한 연구과정에서 얻은 결과를 분석하여 앞으로 예비교사 교육에서 더욱 관심을 두고 지도해야 할 사항에 대해 살펴보았다.

• 한국치위생학회지
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• 제15권2호
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• pp.311-317
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• 2015

Objectives: The purpose of this study was to identify the effects of xylitol and sorbitol mouth rinse on the salivary caries activity levels. Methods: The study subjects were 38 female college students in Gyeongju, Korea. The subjects visited the institution once a week for 4 weeks and the saliva samples were measured for the amount of salivary caries activity levels. The saliva was collected 5 times and incubated in Mitis Salivarius Agar for 48 hours(VS-1203P3L, Vision, Korea) and measured. Results: The Streptococcus mutans CFU decreased by statistically significant amounts as compared to before the experiment within the xylitol group and the sorbitol group(p<0.01). After three weeks of mouth rinse application, Streptococcus mutans CFU of the xylitol group and the sorbitol group showed statistically significant differences(p<0.05). The salivary flow rates within the xylitol group and sorbitol group increased by statistically significant amounts(p<0.01) than before the test. The change in the salivary buffering capacity decreased by a statistically significant amount as compared to before experiment within the xylitol group(p<0.01). Conclusions: The salivary caries activity levels decreased after using xylitol and sorbitol mouth rinse in CFU and the flow rate. The buffering activity levels increased within the xylitol group. Further follow-up studies would be necessary to identify the various effects of xylitol.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제31권4호
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• pp.409-432
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• 2017

본 연구는 최근 과정 중심 평가의 중요성과 함께 주목 받고 있는 형성평가의 정착 및 운영을 위한 방안을 모색하고자 하였다. 그 방안의 하나로 설정한 학생 상호피드백을 통한 형성평가가 초등학교 4학년 학생들의 수학 학업 성취도와 수학적 태도에 미치는 영향을 살펴보았다. 본 연구를 진행하기 위해 동질성이 검증된 실험집단과 비교집단을 선정하여 실험집단에는 학생 상호피드백을 통한 형성평가를, 비교집단에는 본인 확인피드백을 통한 형성평가를 실시하였다. 그 결과, 학생 상호피드백을 통한 형성평가는 학생들의 수학 학업 성취도를 향상시키고, 학생 상호피드백을 통한 형성평가는 수학적 태도도 긍정적으로 변화시켰다. 이는 학생 상호피드백을 통한 형성평가가 초등학생들의 수학 학습에 있어서 인지적, 정의적 측면에 유의미한 영향을 미쳤다고 볼 수 있다.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제30권4호
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• pp.453-468
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• 2016

본 연구자는 만다라를 유아미술교육에 활용하였을 때 유아의 공간과 도형의 개념이 현저하게 향상된 결과를 얻었다. 본 논문은 그 후속연구로 부산광역시 H어린이집의 만3세 유아 44명, 만5세 유아 34명을 대상으로, 만다라와 유사한 구조를 가지는 프랙털 조형 활동이 유아의 공간과 도형의 수학적 개념에 미치는 영향을 연구하였다. 연구결과 만3세 유아는 4개 영역에서, 만5세 유아는 3개 영역에서 유의미함을 보였다. 만3세 유아는 조형 활동에서 과거의 기억을 표현하기 시작했으며, 만5세 유아는 스토리를 만들며 실물과 유사하게 재현하기도 했다. 또한 만5세의 경우 그림과 지점토의 표현에서 성별의 차이가 뚜렷하게 드러났으며, 만다라보다 프랙털이 더욱 효과적임을 보였다.

• 한국운동역학회지
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• 제26권4호
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• pp.413-420
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• 2016

Objective: The purpose of this study was to analyze and compare different kinds of outdoor walking shoes in terms of muscle fatigue and ground reaction force on walking, and to provide foundational data for developing and choosing outdoor walking shoes that fit the users. Method: The study subjects were 30 healthy men. The experiment was conducted by using outdoor walking shoes with different inner and outer harnesses of the midsole, and shapes of the outsole. For data collection, electromyography was used to measure the muscle fatigue of the anterior tibial muscle and gastrocnemii, which contribute to the dorsiflexion and plantarflexion of the ankle joint, and the biceps muscle of the thigh and lateral great muscles, which contribute to the flexion and extension of the knee joint. A GRF measurement device was used to measure the X, Y, and Z axes. Results: In the type A outdoor walking shoes, regarding the hardness of the midsole, the inner part was soft, while the outer part was hard. The vertical ground reaction force was the lowest, which means least impact while walking and light load to the knees and ankles. The type C outdoor walking shoes were intended to provide a good feel in wearing the shoes. The tibialis anterior, biceps femoris, and gastrocnemii indicate low fatigue, which means that during a long-distance walk, it will minimize the fatigue in the muscles of the lower limbs. Conclusion: To sum up the study results, the different types of outdoor walking shoes indicate their unique characteristics in the biomechanical comparison and analysis. However, the difference was not statistically significant. Thus, a systematic and constant follow-up research should be conducted to cope with expanding market for outdoor walking shoes. Lastly, this study is expected to present foundational data and directions for developing outdoor walking shoes.

• 재활치료과학
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• 제7권1호
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• pp.63-77
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• 2018

목적 : 본 연구는 기능적 전기 자극을 병행한 과제 지향적 훈련이 불완전 경수 손상 환자의 손 기능에 미치는 영향을 알아보고자 하였다. 연구방법 : 대상자는 불완전 경수 손상 진단을 받은 성인 3명으로, ABA 설계를 사용하였으며, 연구기간 동안 기초선(A1) 5회기, 중재기(B) 20회기, 재기초선(A2) 5회기로 총 30회기 실시하였다. 중재기(B) 동안 기능적 전기 자극을 병행한 과제 지향적 훈련이 제공되었고, 모든 회기에는 손 기능을 평가하기 위해 상자와 나무토막 검사(Box and Block Test), 떨어지는 막대 잡기(Grip the falling bar)와 먹기 흉내 내기(Simulated feeding)를 측정하였으며, 기초선(A1) 전, 재기초선(A2) 후로 Canadian Occupational Performance Measure(COPM), Jebsen-Taylor Hand Function Test(JTHFT)와 Wolf Motor Function Test(WMFT)를 실시하여 중재 효과를 살펴보았다. 결과 : 모든 대상자는 상자와 나무토막 검사(Box and Block Test), 떨어지는 막대 잡기(Grip the falling bar)와 먹기 흉내 내기(Simulated feeding)를 통해 기초선(A1)보다 중재기(B)에서 우세 손 기능이 향상되었고, 재기초선(A2)에서 그 효과가 유지되었다. 재기초선(A2) 후 COPM, JTHFT와 WMFT의 결과, 우세 손 기능의 향상과 과제 수행도와 만족도의 향상을 보였다. 결론 : 기능적 전기 자극을 병행한 과제 지향적 훈련은 경수 손상 환자의 손 기능뿐만 아니라, 대상자가 선택한 훈련 과제의 과제 수행도와 만족도 향상에 효과적이다.