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.

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.

일측 자골신경의 절단 및 재연결 후 흰쥐 척수에서 신경세포 접착분자(NCAM)의 면역조직반응의 변화에 관한 형태학적 연구

황세진,전복관,안동춘,조원길,김승현 대한신경과학회 1999 대한신경과학회지 Vol.17 No.1

강원도의 생산자서비스업의 분포와 성장(1981~1994)

이학원,장세환 江原大學校 江原文化硏究所 1999 강원문화연구 Vol.18 No.-

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.

柑橘樹의 越冬에 있어 樹體 被覆이 落葉에 미치는 影響

元世鎬,金翰琳 동국대학교 농림과학연구소 1969 農林科學 論文集 Vol.3 No.-

This experiment was made to study the effects of covering treatments-rice-straw (A), straw-mat (B), fishing-net (C), vinyl-film (D), OED spraying (E) and control (F)-on the defoliation of Citrus nushiu MARC. var paraecox TANAKA on Cheju-do through the winter. The results obtained were summarized as follows: 1. The comparison of all treatments v. s. control except OED spraying showed that there was high significance among each of them (B=C<A<E<F<D) but vinyl-film covering showed more defoliation than the control. 2. Straw-mat and fishing-net were most effective in protecting defoliation and there was no significant difference between them. 3. up to the present, the fishing-net for winter has never been applied to citrus culture on Cheju-do, but according to this experiment it was effective in preventing defoliation, handy in covering and removing and more economical than straw-mat.

체외순환 없이 시행한 관상동맥우회술의 조기성적

원태희,최세용,양인숙 이화여자대학교 의과대학 2005 EMJ (Ewha medical journal) Vol.28 No.1

Background : The advances in surgical techniques and stabilizing devices have made the off-pump coronary artery bypass (OPCAB) popular, and good results have been published. We analyzed the early results of OPCAB performed in our hospital. Materials and Methods : Between January 2004 and December 2004, 23 patients underwent OPCAB. There were 14males and 9 females with mean age of 62.6± 10.3years. Preoperative diagnoses were unstable angina in 13(57%), acute myocardial infarction in 9(39%), and stable angina in 1(4%). Preoperative angiographic diagnoses were three-vessel disease in 12 (52%), two-vessel disease in 8(35%), one-vessel disease in 1(4%), and left main disease in 2(9%). Results : The mean number of grafts was 2.6 ±0.9 per patient. Vessels accessed were left anterior descending artery in 23, diagonal branch in 14, obtuse marginal branch in 9, right coronary artery in 12, and posterior descending artery in 1. Left internal mammary artery were used in 22 patients and bilateral internal mammary arteries were used in 1 patient. There was no operative mortality. Postoperative complications were cerebral vascular accident in 1, postoperative bleeding which required operative management in 2, arrhythmia including atrial fibrillation in 5, and minor operative wound problem in 1. Pre-discharge graft patency was evaluated in 11 patients. One internal mammary artery graft was occluded in 11 internal mammary artery graft evaluated. The patency rate was 91%. Seventeen saphenous vein grafts were patent in 19 saphenous vein grafts and the patency rate was 89%. Conclusion : Our result of OPCAB is promising and OPCAB is suggested to be the ideal technique with less morbidity and mortality.

切接時 接着部의 비닐被覆이 活着 및 生育에 미치는 影響

元世鎬 東國大學校 1965 論文集 Vol.2 No.-

In order to promote the formation of healing tissues by preventing dryness of sion and contact portion of sion in veneer-grafting, the grafted plant has usually been mounted with soil only as high as the upper portion of sion or else painted by grafting wax. But, if contact portion of sion is wrapped and tied with vinyl, the grafting operation would be simpler and the cost would be less; and the following are the data of my research work regarding the above statement. 1. In the sections where the grafted portion was painted with grafting wax or wrapped and tied by vinyl, the sion and its contact portion were prevented from becoming dry; the rate of union of the sion was far better. Therefor it is found that wrapping of grafted portion by vinyl bring higher efficiency in veneer-grafting operation. It is the best method form the economical aspect. 2. No differences were recognized on the growth of grafted plants in all sections through germination, green tip and subsequent stages.

동진강 유역 비점오염원 정밀조사

원찬희,정팔진,김민정,조선영,김세훈,김종천 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2002 工學硏究 Vol.33 No.-

Nonpoint source pollution(NSP) arises due to agriculture activity and it is quite an extensive and complicated problem in order to control and has received a great deal of concern during the recent years, whereas point source are known to originate from an estimated volume of contaminant discharged from a distinguishable source. Extensive research work have been conducted and presented in the past with regard to the various characteristics of watershed on Dong Jin River(DJR), however there are certain drawbacks of existing survey for determining important polluting sources, distribution features of pollutants and estimated load of the organic and nutrients from the creeks. Unfortunately, investigation for loadings originating due to agricultural drainage was not satisfactory, although the regional consideration for DJR across Kim Je Field(KJF) as an agricultural area receives a reasonable source point in the agri-pollution management. Therefore it was necessary to carry out a thorough investigation into the diffuse sources resulting, to form the pollution-developing estimation and to evaluate the output roperties and determining various factors in the generation of non-point pollution. Eventually, this research work would serve as an useful tool for the development of predictive pollution management for DJR. Non-point sources in the present work were classified as municipal non-treated sewage water discharged into the river, loadings through agricultural drainages in the dry/wet field and inadequate treatment of wastewater generated from livestocks. The entire duration of the research work was from December-2001 to July-2002. Site measurement were conducted during various season, in a dry season(December), in rainfall, in seed-sowing time and also collecting data from the rural public organizations related to water management was done and examined and examined during the mid of research work. Similarly, domestic wastewater loadings due to population was based on area unit, as City, Country, Up, Myon, Dong, Ri. The Dong Jin River watershed contains small three Creeks, KoBu(KB), DongJin(DJ, including JeongEup(JE) and ChilBo(CB), WonPyong(WP). It was further divided into 32 sub-watersheds which comprises of further 5,18,9 watersheds in the creeks respectively. The results obtained from research work are presented as follows. Animal productions have marked differences in the rate of pollutant loadings reported in the following sequence: DJ(only CE)>WP>CB>KB, in a case of Korean cow and milk cow. However, it was revealed that WP creek became significantly higher than any other livestocks. According to statistical data for land use, rice field(369.0㎢) and forest(378㎢) have much occupation prior to dry paddies(125.0㎢), residential land(32.0㎢) and others(5.0㎢). Especially, rice fields receives 2.5∼3 times than dry paddies in size.

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.