Electrical, Thermal, and Thermoelectric Transport Properties of Se-doped Polycrystalline Re2Te5

Se Woong Lee,Okmin Park,Hyun-Sik Kim,Won-Seon Seo,Sang-il Kim 대한금속·재료학회 2022 대한금속·재료학회지 Vol.60 No.12

Re2Te5 is considered a potential thermoelectric material because of its intrinsically low thermalconductivity, due to its complex crystal structure. Herein, a series of Se-doped Re2Te5 (Re2Te5-xSex, x = 0, 0.2,1, and 2) samples were synthesized, and their electrical and thermal transport properties were investigated. Pure orthorhombic Re2Te5 phases were successfully synthesized without any impurities for all compositions,and the continuous decrease in the calculated lattice parameters confirmed the substitution of Se atoms atthe Te sites. A maximum power factor of 0.135 mW/mK2was achieved for the sample with x = 0.2 at 880 K,mainly due to the increase in carrier concentration and electrical conductivity. The lattice thermalconductivity significantly decreased for all doped samples, which was attributed to the point defect phononscattering caused by Se doping. The thermoelectric figure of merit, zT reached a maximum value of 0.20 at880 K for Re2Te4.8Se0.2 (x = 0.2) sample, which was approximately 22% higher than that of the pristine Re2Te5sample. The weighted mobility, quality factor, and expected zT were calculated to evaluate the optimizationof the power factor and zT.

공급사슬에서 수량할인과 수익공유를 반영한 계약

박세호(Se Ho Park),이영해(Young Hae Lee),조동원(Dong Won Cho) 한국SCM학회 2012 한국SCM학회지 Vol.12 No.2

One of the most important reasons in pursuit of supply chain management is to prevent sub-optimization caused by decentralized decision making over the various entities. As supply chain coordination approach to overcome such a setting, contract mechanisms have frequently been used. However, a coordinated supply chain might fail to provide additional profit to one of the players. In result, it is necessary that a contract mechanism is designed to achieve the same profit in a centralized situation (coordination) and to improve the benefit of all the supply chain players (winwin). In this paper, we address supply chain contract based on revenue sharing and quantity discount considering price and service level. We show that the trade parameters among different entities in the supply chain contract can be chosen to achieve coordination and a win-win outcome.

국가 대표급과 제주도 고교 대표급 수영선수들의 그랩 스타트의 운동학적 분석

김철원,김승곤,오만원,임상용,김성찬,이창준,남사웅,이세형,류재청,신석종,김세민 濟州大學敎 體育科學硏究所 1998 체육과학연구 Vol.4 No.-

The purpose of the study was to undertaken to analysis the Grab starting technique between national representive team(3) and Cheju's representive team(3) with 3D cinematography. The conclusions obtained were as follows: Cheju's showed more elapsed time than national representive team on starting block. and more vertical than horizontal direction of COG position, more concentrated vertical velocity & acceleration than forward direction. Therefore It is necessory for cheju's to train balanced trust force in horizontal and vertical direction in grab starting technique.

아동보호전문기관 사회복지사의 윤리적 딜레마와 의사결정에 관한 연구

이세원(Lee Se-Won) 한국사회복지학회 2008 한국사회복지학 Vol.60 No.1

본 연구는 아동보호전문기관 사회복지사들의 윤리적 딜레마와 의사결정을 중심으로 연구를 진행하여 그들의 윤리적 고충을 이해하는 동시에 실천적이고 정책적인 제언을 하는 데에 목적이 있다. 본 연구의 수행을 위하여 질적연구방법론 중에서도 현상학적 연구방법을 사용하였고, 14명의 아동보호전문기관 사회복지사와의 인터뷰 내용을 Colaizzi(1978)의 분석단계에 따라 분석하였다. 총 8개의 주제묶음과 26개의 소주제들을 통해 아동보호전문기관 사회복지사는 ‘정책/제도의 미흡함과 업무의 과다 속에서 피학대 아동을 만나면서 직접적이고 간접적인 윤리적 딜레마에 빠짐’을 대주제로 도출하고, 총 4개의 주제묶음과 9개의 소주제들을 통해 ‘책임과 부담을 떠안은 채로 최선이라 생각하며 의사결정을 수행함’을 대주제로 도출할 수 있었다. 이에, 이와 관련된 향후 논의점들을 제시하였다. The aim of this study is to understand the ethical struggles of Child Protective Service(CPS) social workers and to indicate some implications for future studies by conducting research focusing on their ethical dilemmas and decision-making. This study used qualitative methods, in particular the phenomenological approach and 14 in-depth semi-structured interviews with CPS social workers, and were conducted and analyzed using the procedures of Colaizzi(1978). This study looks at the following research questions: 1) What kind of ethical dilemmas do CPS social workers encounter? This means what ethical dilemmas do they directly or indirectly encounter because of policy or system inadequacies and huge caseloads. 2) How do the CPS social workers make decisions when they are faced with ethical dilemmas? Making the best decisions with all of their responsibilities and burdens is the focus of this question. This study suggests the following discussions: First, efforts to emphasize 'ethics' at CPS are needed. Second, proper policies and systems based on the Korean situation are needed so that CPS social workers won’t have to face 'needless' ethical dilemmas. Third, an index of ethical problems or ethical codes is necessary because principles are important to those social workers who face ethical dilemmas. Fourth, an ethical committee that protects the CPS social workers by supporting their decisions and being responsible for them is needed. Last, a debriefing system that reduces a CPS social worker's psychological trauma caused by ethical dilemmas should be available.

바이오매스 합성가스를 이용한 엔진 발전 시스템의 경제성 평가

문지홍(Ji Hong Moon),이정우(Jeung Woo Lee),방병열(Byung Ryeul Bang),김세원(Se Won Kim),이은도(Uen Do Lee) 한국열환경공학회 2010 한국열환경공학회 학술대회지 Vol.2010 No.추계

Biomass, a carbon neutral fuel, is one of the fastest growing renewable energy sources. In this study, economic feasibility of small scale power generation system using syngas from biomass has been investigated. Effects of important variables such as capital investment, cost of waste wood, renewable energy certificate(REC), system marginal price(SMP) on the benefit of business have been analyzed. Internal rate of return(IRR) was predicted as 16.90%, which implicates the business is promising based on the assumptions such as SMP of 137 Won/kWh, capital cost of 4.7 billion won, and waste wood price of 30 thousand won. Major factors affecting the benefit of business are as follows; system marginal price, operational rate, capital investment, expenditure of waste wood, certified emission reduction.

잠복원발종양의 원발병소 진단시 내시경 유도하 생검 및 구개편도적출의 진단적 의의

김세헌,김광문,이준협,이승수,서진원,홍원표 대한이비인후과학회 1998 대한이비인후과학회지 두경부외과학 Vol.41 No.3

전통 발효 식품으로부터 분리한 젖산균들의 생리 기능성

신자원, 현세희, 장인택, 이종수 배재대학교 자연과학연구소 2013 自然科學論文集 Vol.24 No.1

To screen useful bacteria for functional food industry in strains from Korean fermented foods, physiological functionality of lactic acid bacteria from Korean kimchi were investigated. Antihypertensive angiotensin Ⅰ-converting enzyme(ACE) inhibitory activity were showed very high 56.0~85.2% in all lactic acid bacteria and especially, the highest ACE inhibitory activity of 87.0% was showed in Leuconostoc mesenteroides subsp. mesenteroides LB-643. Whitening tyrosinase inhibitory activity and anti-aging antioxidant activity were showed the highest in Lactobacillus brevis LB-879(72.1%) and Lactobacillus graminis LB-350(32.2%), respectively. Anti-gout xanthin oxidase inhibitory and fibrinolytic activity were also high in Lactobacillus paraplantarum LB-354(17.8%) and Lactobacillus pentosus LB-225(clear zone; 17.0㎜), respectively.

果樹苗木의 栽植時期, 覆土가 活着 및 生育에 미치는 影響

元世鎬 동국대학교 농림과학연구소 1967 農林科學 論文集 Vol.1 No.-

Fruit trees are planted during the dormant period in order to reduce injury from the damage of roots when the fruit nursery stocks are dug. In our country, the air temperature goes low very in the winter ; and fruit trees are planted either in the fall or spring so as to void freezing injury. It is generally said, the fruit trees planted in the fall grow better than the trees planted in the spring. But this is the case for the region where the werther is comparatively moist and not so cold inthe winter and spring planting is recommended for the region where the weather is dry and cold in the winter; however, no definit suggestion was made any season would be better for a certain reion. In this connection, this study has been made to examine planting time by kind of fruit trees in Seoul region. The sarvival of planted trees are so important in planting fruit trees that it also was examined in this study. The results are summarized as follows: 1, In planting apple, Japanese pear, peach, plum and grape; the trees were planted in the fall showed generally better growth than the trees planted in the spring. In the case planted in the fall or spsing the trees, the trees planted in early season generally showed better growth. 2, The trees hilled after trees planted generally showed better growth than those of not hilled. 3, In planting apples, Japanese pears, peaches and plums; no difference was observed on the survival of trees between the trees planted in the fall and the trees planted in the spring; but in planting grapes, suruival of the grape trees not hilled was markedly poor than those of hilled in case of planting late season in the fall planting. 4, No difference was observed on both the budding and openeing leaves in all plots.

복숭아의 生理的 落果에 관한 硏究 : 복숭아의 生理的落果와 總糖, 窒素 및 水分과의 相關

元世鎬 東國大學校 1967 論文集 Vol.3-4 No.-

The physiological drop occurs heavily on peach trees. The lack of fertilization and the discontinuation of development of embryo are the causes of the physiological drop; and the total sugar, nitrogen and water in the fruits are the factors closely related to the discontinuation of development of embryo. It is said the deficiency of total sugar, nitrogen and water in the fruits cause the physiological drop, and the deficiency of nitrogen or water supply in the soil cause the physiological drop and also the excessive supply of nitrogen or water in the soil cause the physiological drop. It is easy to understand that the physiological drop occurs when the total sugar, nitrogen and water are short in the fruits, and also when the nitrogen or water supply were deficient in the soil, but it is a little hard to understand why the physiological drop eccurs when nitrogen or water is excessively supplied in the soil. Therefore this experiment was made to check the relationship between the physiological drop and the total sugar, nitrogen and water in the fruits, and nitrogen or water in the soil. The results obtained in this experiment are summarized as follows: 1. The dropped fruits contained less total sugar than the fruits not dropped. This means the deficiency of total sugar supply on the fuits is the cause of physiological drop. 2. The deficiency of nitrogen or water supply in the soil reduced absorptioin of them in the plant body; the nitrogen or water content ini the leaves were reduced and it caused the physiological drop; and the dropped fruits contained less nitrogen or water than the fruits not dropped. This means the short supply of nitrogen or water to a fruit causes physiological drop. 3. Excessive nitrogen or water supply in the soil results in the significant absorption of nitrogen or water in the plant body, and the leaves also contained more nitrogen or water, however, physiological drop occured in this case also. The dropped fruits contained less nitrogen or water than the fruits not dropped. In this case vegetative growth of the shoots and leaves were very vigorous. Also, when the excessive supply of nitrogen or water was given to the soil, the physiological drop takes place. This phenomenon, considered in the light of the above, because too much nitrogen or water was exhausted in the vegetative growth of shoots and leaves. As a result, it is supposed that has been caused by the short supply of nitrogen or water into the fruits.

브레이징 온도 변화에 따른 ZrO2와 Ti-6Al-4V의 접합 특성

기세호,박상윤,허영구,정재필,김원중 大韓齒科補綴學會 2012 대한치과보철학회지 Vol.50 No.3

Purpose: In this study, brazing characteristics of ZrO2 and Ti-6Al-4V brazed joints with increasing temperature were investigated. Materials and methods: The sample size of the ZrO2 was 3 mm × 3 mm × 3 mm (thickness), and Ti-6Al-4V was 10 mm (diameter) × 5 mm (thickness). The filler metal consisted of Ag-Cu-Sn-Ti was prepared in powder form. The brazing sample was heated in a vacuum furnace under 5 × 10-6 torr atmosphere, while the brazing temperature was changed from 700 to 800℃ for 30 min. Results: The experimental results shows that brazed joint of ZrO2 and Ti-6Al-4V occurred at 700 - 800℃. Brazed joint consisted of Ag-rich matrix and Cu-rich phase. A Cu-Ti intermetallic compounds and a Ti-Sn-Cu-Ag alloy were produced along the Ti-6Al-4V bonded interface. Thickness of the reacted layer along the Ti-6Al-4V bonded interface was increased with brazing temperature. Defect ratios of ZrO2 and Ti-6Al-4V bonded interfaces decreased with brazing temperature. Conclusion: Thickness and defect ratio of brazed joints were decreased with increasing temperature. Zirconia was not wetting with filler metal, because the reaction between ZrO2 and Ti did not occur enough. 연구 목적: 온도 변화에 따른 ZrO2와 Ti-6Al-4V의 접합 특성에 대해 알아보기 위하여 새로운 브레이징 합금을 제조하고, 브레이징 온도가 접합 특성에 미치는 영향에 대하여 조사하고자 하였다. 연구 재료 및 방법: 본 연구에서 사용된 시편으로는 실험용 ZrO2 모재(ZirBlank-PS, Acucera, Inc., Gyeonggi-do, Korea)는 소결 전의 블록형태(65 mm × 36 mm × 12 mm (t))이며, 이를 잘라 사포(#2400)로 표면연마 후 소결하였다. 소결된 ZrO2 시편의 크기는 3 mm × 3 mm × 3 mm (t) 이다. Ti-6Al-4V 모재(Ti 6Al 4V ELI CG Bar, TMS, Washington, USA)는 직경 10 mm × 5 mm (t)를 사용하였다. 소결된 ZrO2와 Ti-6Al-4V의 접합을 위하여 브레이징 합금을 제조하였다. 시편을 3군으로 나누어A군은 700℃에서, B군은 750℃에서, C군은 800℃에서 각각 브레이징 하였다. 브레이징 부의 두께와 결함율의 측정은 각 군당 하나의 시편으로 각 시편 당 5회씩 반복 측정하여 평균값을 취하였다. 결과: 브레이징 합금을 사용하여 진공 브레이징을 수행한 결과 ZrO2 와 Ti-6Al-4V 는 700℃ - 800℃에서 양호한 접합을 보였다. 브레이징 후 브레이징 온도 변화에 따른 브레이징 부의 두께 및 결함율의 변화는SEM을 사용하여 측정하였다. 브레이징 온도가 700℃에서 800℃로 증가함에 따라 CuTi 금속간 화합물 층 및 Ti-Sn-Cu-Ag계 화합물 층의 두께는 각각 4.5 ㎛에서 10.3 ㎛로, 3.1 ㎛에서 5.0 ㎛로 증가되었다. 또한 브레이징 온도가 700℃에서 800℃로 증가함에 따라 브레이징 접합계면의 결함율은 ZrO2 및 Ti-6Al-4V 계면에서 각각25%에서 16.3%, 5%에서 1.5%로 감소되었다. 결론: 브레이징 온도가 700℃에서 800℃로 증가됨에 따라, 브레이징 접합계면의 결함율은 ZrO2 및 Ti-6Al-4V 계면에서 모두 감소되었다. 이는 결함부에서 ZrO2와 활성원소인 Ti과의 반응이 충분히 일어나지 않아서 브레이징 합금이 ZrO2에 웨팅되지 않은 것이 원인이라고 사료된다.