합성 wustite 의 흑연에 의한 환원속도론

김선효,윤종규 대한금속재료학회(대한금속학회) 1979 대한금속·재료학회지 Vol.17 No.4

反應中 생기는 氣媒介體 CO와 CO₂를 通해 일어나는 合成 wu¨stite의 黑鉛에 의한 還元反應이 950℃∼1075℃ 溫度範圍에서 示差熱分析裝置에 의해 Ar분위기中의 등온 條件下에서 行해졌다. 還元反應에 대한 機構와 速度는 Rao에 의해 제시된 modified physico-chemical model에 의해 조사되었으며 아울러 이의 妥當性에 대한 硏究가 이루어졌다. 黑鉛함량 및 wu¨stite 粒子크기와 混合體에 加한 壓力이 還元反應速度에 미치는 영향도 分析검토하였다. 反應의 초기단계와 끝部分을 제외한全 還元反應은 Rao의 modified model에 잘 들어맞고 있음이 나타났다. 氣相媒介體를 通한 wu¨stite의 黑鉛에 의한 還元反應에 必要한 活法化에너지는 57Kcal/㏖임이 얻어졌고 이 값은 文獻과 잘 일치하고 있는 것으로 밝혀졌다. 還元反應速度式은 X=2au[1-exp(-kt)〕이 됨이 나타났다. Reduction reaction of synthetic Wustite by graphite through the gaseous intermediates CO and CO₂occuring during the reaction was carried out isothermally within the temperature range 950℃ to 1075℃ in an inert Ar atmosphere with T.G.-D.T.A. analysis technique. The mechanism and the rate of reduction reaction were investigated with modified physico-chemical model derived by Rao and the suitability of Rao's model to this reaction system was studied, too. The effects of variables such as C/FeO molar ratio, Wustite powder size to the rate of reduction reaction and the compactness of mixed powder were discussed. The overall reduction reaction but the initial stage and the tail part of reaction was considered to be well fitted to the modified physico-chemical model. The activation energy for the Wustite reduction by graphite through the gaseous intermediates is calculated to be 57Kcal/㏖ and this value is reasonably in good agreement with the literature. The rate equation of reduction reaction through the gaseous intermediates was found to be X=2av [1-exp (-kt).〕.

변경된 항아리형 초광대역 패치안테나의 설계에 관한 연구

김선효,이영철,박기원 한국전자통신학회 2016 한국전자통신학회 논문지 Vol.11 No.3

This paper implemented an ultra-wideband(UWB) antenna by using a modified barrel-shaped patch antenna. The designed UWB patch antenna was optimized to match UWB technical specifications by considering the sizes of barrel circle and oval(notch) which is distance between the patch and contact surface and designed antenna was implemented by 10 mm(R1)×21.8mm size. Optimal values on the basis of simulated reflective loss results, the surface current distribution of designed patch antenna was analyzed in order to check operation mode of antenna and wideband mechanism. Experimental results of implemented UWB antenna, The voltage standing wave ratio was 2 or less in the 1.775-13.075 GHz band. And the maximum gain of approx. 5 dBi was found in 9-10 GHz. This result meets the characteristics of ultra-wideband and the proposed antenna will be applicable to an ultra-wideband system. 본 논문에서는 변형된 항아리형 패치안테나를 사용하여 초광대역 안테나를 구현하였다. 설계한 패치안테나의 물리적 길이와 홈(노치)를 광대역 특성 조건으로 최적화시켰으며, 10 mm×21.8mm크기로 설계된 변형된 항아리형 패치안테나를 제작하였다. 설계된 최적화 패치안테나의 표면 전류분포를 분석하고 초 광대역 특성 조건을 만족함을 확인하였다. 실험 결과 제작된 초광대역 패치안테나의 전압정재파비는 1.775〜13.075 GHz대역에서 2 이하의 특성을 나타내었으며, 9∼10 GHz 대역에서 약 5 dBi의 최대이득이 나타내었다.. 이와 같은 실험결과는 초 광대역 통신시스템에 활용이 가능할 것으로 판단된다.

우유 섭취와 건강과의 관련성 고찰

김선효 공주대학교 과학교육연구소 2015 과학교육연구 Vol.45 No.1

Milk is a rich source of health functional component, thus milk is helpful for preventing various diseases such as osteoporosis, hypertension, cancer, cardiovascular disease and diabetes. This study was performed to review the relationship between milk and health to provide a scientific evidence for appropriate use of milk.

우유의 영양성분과 영양적 가치 고찰

김선효 공주대학교 과학교육연구소 2015 과학교육연구 Vol.45 No.1

Milk is a rich source of fat, protein, amino acids, vitamins and minerals, thus we should consume 1-2 cups/day of milk for nutrition and health. However, anti-milk information is spreaded recently and this trend prevents right consumption of milk. This study was performed to review the nutritional values of milk to provide a scientific evidence of milk and support the reasonable consumption of milk.

22.9kV 중 전압 전력선 통신을 위한 금속귀로 채널과 대지귀로 채널의 특성분석

김선효,이원태,이영철,신철재 한국통신학회 2002 韓國通信學會論文誌 Vol.27 No.9B

-적'형의 통사적 범주와 의미

김선효 서울대학교 국어국문학과 2002 冠嶽語文硏究 Vol.27 No.-

중학교 가정교과서의 우유 교육 내용 분석과 중학생의 우유・유제품 섭취 실태 및 영양지식 조사 - 충남 공주시 중학생을 중심으로 -

김선효 한국가정과교육학회 2017 한국가정과교육학회지 Vol.29 No.4

This study was performed to analyze education contents related to milk in current home economics textbooks of middle school, and to investigate intake status, consumption behaviors, perception and nutritional knowledge of milk and dairy products among 364 middle school students in Gongju for improvement of milk education in home economics subjects and milk intake of adolescents. As a result, education contents of milk and dairy products in home economics textbooks currently applied in middle school were major nutrients, consumption method for balanced diet, and selection and storage of milk and dairy products, thus it tended not to match current food trend. Only 30.5% of subjects met 2 cups of milk a day, the recommended level. The main reason for drinking milk was to 'be taller' and 'to quench thirst' and there was a difference by gender(p<0.01). The rate of not participating in school milk program was 23.1% of total and its satisfaction was moderate. The most popular dairy products by subjects were ice cream, followed by yogurt and cheese, and the choice of milk was focused on 'taste' or 'expiration date'. The rate of knowing certification mark of K-MILK was low at 28.8%, and most subjects knew as 'domestic milk use'. In home economics class, experience-based learning such as cow ranch experience was the most preferred instruction method for milk followed by laboratory practice and lecture, and there was a difference by gender(p<0.001). Perception degree of milk and dairy products was moderate and male subjects were more positively perceived than female subjects(p<0.01). Nutritional knowledge level of milk and dairy products was moderate and female subjects were higher than male subjects(p<0.01). Therefore, education contents of milk and dairy products of home economics textbooks of middle school should be centered on real life in accordance with food trend, and applied student participation-based instruction methods such as experience-based learning. In addition, it is necessary to enhance taste and merchandise of milk and to provide them with preferred milk and dairy products in school milk program for improvement of milk intake of adolescents. 본 연구는 충남 공주지역 중학교에 재학 중인 1∼3학년 남녀 학생 364명을 대상으로 중학교 현행 가정교과서의 우유 교육 내용을 분석하고 우유・유제품 관련 섭취 실태, 소비행동, 인식 및 영양지식을 조사함으로써 가정교과서의 우유 내용이 우유를 바르게 섭취하도록 돕고 중학생의 우유 섭취 향상을 위한 기초자료를 제공하고자 실시하였다. 현재 중학교에서 적용 중인 가정교과서의 우유 교육 내용은 우유의 영양성분, 식단작성을 위한 우유・유제품 섭취 방법, 선택과 보관방법에 대한 일반적 내용이어서 청소년의 우유・유제품 소비 실태를 반영하지 못하는 것으로 파악되었다. 조사대상자에서 우유 권장수준인 하루에 2컵을 충족하는 비율은 30.5%뿐이었으며 성별에 따른 차이가 없이 전체적으로 우유 섭취량이 낮았다. 우유를 마시는 주된 이유는 ‘키 크게 하려고’가 가장 많았고, 그 다음으로 ‘갈증을 해소하려고’, ‘맛이 있어서’가 많았으며 성별에 따른 차이가 있었다(p<0.01). 우유를 마시는 방법은 우유만 마신다는 비율이 66.8%로 높았으나 그 외에 시리얼이나, 제티 등을 섞어 마시고 있었으며 성별에 따른 차이가 있었다(p<0.05). 학교우유급식에 참여하지 않는 비율이 23.1%이었으며, 만족하는 비율은 58.9%로 높지 않았다. 유제품 중 가장 즐겨 먹는 것은 아이스크림이었고 그 다음으로 요구르트, 치즈로 나타났다. 우유 선택시 ‘맛’, ‘유통기한’을 중시하였고 ‘영양’을 중시하는 비율은 낮았으며 성별에 따른 차이는 없었다. 우유・유제품 소비촉진을 위해 ‘더 엄격한 위생관리’를 원하는 비율이 가장 높았고, 이어서 ‘맛의 개선’, ‘제품 종류의 다양화’ 등이 높았으며 성별에 따른 차이가 있었다(p<0.05). 좋아하는 우유 용기는 종이팩이 59.3%로 높았고 그 다음이 플라스틱병, 유리병이 높았으며 성별에 따른 차이가 있었다(p<0.001). K-MILK 인증마크를 안다는 비율은 28.8%뿐으로 낮았다. 그 의미를 ‘국내산 우유 사용’으로 알고 있는 비율이 높았으며 성별에 따른 차이는 없었다. 중학교 가정교과에서 우유 관련해 원하는 수업방법은 목장체험 등 체험학습이 가장 높았고 그 다음으로 실험실습, 강의식 등으로 나타났으며 성별에 따른 차이가 있었다(p<0.001). 우유・유제품에 대한 인식은 보통 정도이었으며 남자가 여자보다 긍정적이었다(p<0.01). 우유・유제품에 대한 영양지식은 양호한 수준이었으며 여자가 남자보다 높았다(p<0.01). 따라서 중등학교 가정교과서의 우유 교육 내용을 청소년의 소비 흐름을 고려해 구성하고 실생활 중심의 학습이 될 수 있도록 돕는 수업방법을 적용함으로써 청소년의 바른 우유・유제품 이용으로 연결되도록 지원하는 것이 필요하다고 하겠다. 또한 설문 조사 결과 우유 섭취량을 늘리는 것이 시급하였으며 이를 위해 우유 맛의 개선, 우유와 동반간식을 제공하는 다양한 상품 개발, 우유 용기 및 용량 개선, 우유 섭취에 기여도가 높은 학교우유급식의 참여 제고를 위한 독려 및 선호도 높은 우유・유제품의 병행・제공 등이 필요하다고 하겠다.

우리나라 고등학생의 식품 및 영양소 섭취 변화 추이 - 2007~2015 국민건강영양조사를 이용하여 -

김선효,Kim, Sun Hyo 한국식품영양학회 2020 韓國食品營養學會誌 Vol.33 No.5

This study assessed yearly trends of food and nutrient intake among high school students aged 16 to 18 years (n=2,377) using the 2007~2015 Korea National Health and Nutrition Examination Survey (KNHANES). Yearly trends of food or nutrient intake were analyzed via logistic regression analysis. The results showed that consumption of sugars & sweets, and beverages & alcohols was increased rapidly during this period (p<0.0001). Intake of meat & meat products, and fish & shellfish also was increased (p=0.0008). Intake of grains and grain products was increased until year 2011 but declined after 2012 (p=0.0025). Consumption of vegetables, and milk & milk products was decreased (p=0.0395). Intake of protein, fat, thiamin, riboflavin, niacin, and iron was increased (p=0.0445). Carbohydrate energy ratio was decreased, whereas fat energy ratio was increased (p=0.0235). Most nutrient intakes satisfied the dietary reference intakes for Koreans except dietary fiber (19.6~26.2%), calcium (46.9~55.2%) and sodium (more than 221.4%) during this period. There was a significant positive correlation between most food group intakes and most nutrient intakes (p=0.0468). Therefore, it is crucial to increase dietary fiber and calcium intake and decrease consumption of sugars, fats and sodium through diverse eating of food groups to ensure balanced nutrition of subjects.

CaO-SiO2-Al2O3-MgOsat-FetO (〈10wt%) 계 래이들 슬래그중 MgO 및 FetO 가 재산화반응과 탈황정련능에 미치는 영향

김선효,서정도 대한금속재료학회(대한금속학회) 1998 대한금속·재료학회지 Vol.36 No.4

The effect of MgO and Fe_tO on the reoxidation and sulfide capacity of CaO-SiO₂ Al₂O₃ MgO_(sat)-Fe_t O( <10 wt% )slag system was investigated through the slag/metal equilibrium technique using MgO crucible at 1873 K for clean steel technology in ladle refining process. The MgO added into a slag to prevent the dissolution of refractory gives the high possibility to cause reoxidation of aluminum in liquid iron and deteriorates sulfide capacity of slag system. The CaO-SiO₂ Al₂O₃ MgO_(sat) slag system containing around 5 wt% Fe_tO is superior to that containing Fe_t O less than 2 wt% from the standpoint of both reoxidation of aluminum in liquid iron and sulfide capacity. The sulfide capacity as a function of slag composition could be obtained at 1873 K. logC_(S^(2-))=X_(CaO)-5.59X_(SiO₂)-5.30X_(Al₂O₃)+0.29X_(Mgo)+7.42X_(Fe₃O)-1.33.

중국피진영어(Chinese Pidgin English)의 문법론적 특성 -『英語集全』(1862)을 중심으로-

김선효,정성훈 한국언어학회 2019 언어 Vol.44 No.3

The purpose of this paper is to inquire into the grammatical characteristics of Chinese Pidgin English(CPE) based on The Chinese and English Instructor(1862), which was written in English, Cantonese and CPE in the 19th century. The Chinese and English Instructor was written by Tong Ting Kü, a trade businessman in Guangdong, and is an extant books consisting of six volumes. We examined the morphosyntactic characteristics of CPE based on the transcriptive data of Volume 6. First of all, CPE was strongly influenced by Cantonese. For instance, 'side, time, man' are combined with place nouns, time nouns, and job nouns respectively, and an interrogative pronoun structures presented such as ‘how fashion (how), what for(why), what thing(what)’. The classifier structure combined with a classifier 'piece', and the interrogative sentence 'V no V' are also influenced by Cantonese. Secondly, CPE was unstable or unstructured language due to the conflict between English and Cantonese grammar. The subjective of first-person pronouns was 'my', the objective of first-person pronouns was 'me', the second-person pronouns, 'you', and third-person pronouns, 'he'. Also the tense, aspect, modality categories such as 'can, must, have, have got, belong' were unstable, because it was mixed the function of modal verbs up with the copula. As for the sentence type of CPE, there were a declarative sentence, an interrogative sentence, and an imperative sentence. In particular, the imperative sentence tended to appear with 'make'. The negative sentence appeared only with the negative operator ‘no’. The word order of CPE was SVO, but the time adverbs and the interrogative pronouns were not restricted by place constraints.