푸른길 공원의 대기 환경 특성에 관한 연구

민경우,이경석,박옥현,윤관주,김도술,박세일,정원삼,이대행,조영관,Min, Kyoung-Woo,Lee, Kyoung-Soek,Park, Ok-Hyun,Yoon, Kwan-Ju,Kim, Do-Sool,Park, Se-Il,Jeung, Won-Sam,Lee, Dae-Hang,Cho, Young-Gwan 한국환경보건학회 2015 한국환경보건학회지 Vol.41 No.3

Objectives: This study aimed to survey the characteristics of air quality and meteorological conditions in a greenway park. Methods: We measured meteorological and health related factors, including noise, particulate matter ($PM_{10}$) and selected gaseous air pollutants at three locations in a greenway park and on a general roadside as comparison. The measurements were repeated four times from April to October 2014. Results: The average air temperature in the greenway park was $20.7^{\circ}C$ which was $1-2^{\circ}C$ lower than on the general roadside. The average $PM_{10}$ concentration in the greenway park was $85.0{\mu}g/m^3$, a level 2-3 times lower than that at the roadside. The noise level at the greenway site was 4.4 dB(A)- 23.0 dB(A) lower than at the roadside. The average CO, $CO_2$, $SO_2$ and NOx concentrations in the greenway park were lower than at the roadside. The average phytoncide and anions concentrations in the greenway park were higher than at the roadside. Conclusions: The urban forest of the greenway park may have some impact on air quality and meteorological conditions.

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.

중소규모 사업장 근로자에서의 건강위험평가

박정일,이세훈,이강숙,이원철 가톨릭대학산업의학센타 산업의학연구소 1994 韓國의 産業醫學 Vol.33 No.3

This study was carried out to assess of knowledge(K). attitude(A) and practice(P) on general health risk factors in small and medium scale industry workers in Kimpo area. We used self-administered questionnaire regarding the physical exercise, smoking, drinking, intake of fatty diet, mental stress, diet habit, hypertension management, hepatitis, sleep, personal hygiene. The results obtained were as follows : 1. There were significant differences among age groups in attitude and practice but not significant in knowledge, and above 40 years old age group took the higest scores in KAP. 2. There were significant differences between male and female subjects on total mean scores of KAP. 3. There were not significant differences among groups in size of enterprise and work duration. 4. The white collar workers had high scores than blue collar workers but there were no significant differences on attitude and practice. 5. When stepwise multiple regression analysis was done, work status and sex were significantly attributed to knowledge, age and sex were attributed to attitude, and sex was attributed to practice, but the coefficient of determination were very low. In conclusion in small and medium scale industry workers, there were weak or no effects of age, sex, size of enterprise, work duration and work status on knowledge, attitude and practice regarding general health risk. So it suggested that the health promotion program including health education had to be carried out on all members of workers not on specific group.

O_3처리가 柑橘의 貯藏性과 品質에 미치는 영향

박세원,홍세진 建國大學校附設農業資源開發硏究所 2002 農資源開發論集 Vol.24 No.-

The effects of O_3 treatment on storability and quality in mandarins were investigated. The gas of O_3 was treated to harvested mandarins for 60 min. at a rate of 20 l/min at every seven-day interval for four times. The O_3 treated mandarins and non-treated mandarins were stored for one month at room temperature. The weight loss, soluble solid and citric acid in mandarins were measured during storage. The O_3 treated and non-treated mandarins had similar weight loss, soluble solid and citric acid contents. The percentage of decay in mandarins significantly differed between O_3 treated and non-treated: the non-treated mandarins had 14.3% of decay but the O_3 treated mandarins had 1.43% of decay. This result indicated that O_3 treatment had an effect of sterilization resulting in reduced fruit decay rate and enhanced storability in mandarins.

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.

경복궁 근정전 목부재의 수종분석

박원규,김세종 한국목재공학회 2004 목재공학 Vol.32 No.1

경복궁의 정전 건물인 근정전에 쓰인 목재의 수종을 식별하기 위하여 기둥, 보, 도리, 창방, 박공 등 총 144점에 대하여 조사한 결과, 소나무와 전나무 두 수종이 식별되었다. 기둥은 1층의 경우 평주 20개 중 11개가 전나무, 9개가 소나무, 내진고주는 12개 중 7개가 전나무, 5개가 소나무, 그리고 귀고주는 3개가 전나무, 1개가 소나무로 식별되어 소나무보다 전나무가 차지하는 비율이 더 높았다. 2층 기둥 16개는 모두 소나무로 구성되어 있었다. 기둥 이외의 다른 부재는 총 92개 중 도리 2개만이 전나무였고, 나머지는 모두 소나무였다. 우리나라·궁궐의 목재가 소나무로 만들어졌다는 통설은 사실과 다르며 재료 수급에 따라 다른 수종도 사용되었음이 밝혀졌다. 조선말 소나무 長大材가 고갈되어 강도가 떨어지는 전나무로 기둥을 많이 쓸 수밖에 없었던 것으로 생각된다. The purpose of this study is to identify the species of wood members used in the Keunjungjeon Hall, main building of the Kyungbok palace in Seoul. The total 144 samples consist of 52 from pillars and 92 from other wood members. Only two species were identified, which were Abies holophyllu Max. (needle fir) and Pinus densifloru Sieb. et Zucc. (Japanese red pine). For the pillars, A. holophyllu were more abundantly used than P. densiflora. Among 20 outer pillars ('Pyeongju'), 11 were A. bolopbylla and 9 were P. densiflora Among 12 inner pillars ("Naejinkoju'), 7 were A. bolopbylla, and 5 were P densflora Among 4 inner corner pillars ("Gwikoju'), 3 were A. bolopbylla and 1 was P densflora For 92 other wood members, only 2 purlins were A. bolopbylla and the others were all P densflora The results suggest that the common opinion 'Palace buildings of Korea are made from red pine woods' should be corrected We think that fir logs might be used for the pillars instead of pines because long and straight pine were not available during 1860s due to heavy utilization of pines as construction and fuel materials in the late Chosun period.

인발 성형 공정을 이용한 carbon-glass hybrid composite 제작

박상윤,최원종,강길호,문초록,김세영 한국항공대학교 항공우주산업기술연구소 2002 航空宇宙産業技術硏究所 硏究誌 Vol.12 No.-

단면이 일정한 구조용 복합재료 제조공정에 널리 사용되고 있는 pultrusion 공정을 이용하여 glass-carbon fiber hybrid composite을 제조하였다. 열분석을 통하여 모재의 경화온도와 경화시간을 분석한 후 금형의 온도와 pulling speed를 결정하였다. 다양한 섬유 비율의 hybrid composite를 제작하였으며 flexural modulus를 측정한 결과 rule of mixture를 이용한 예상치 보다 높은 값을 보였다. Glass-carbon hybrid composite was manufactured by pultrusion process. The major processing conditions such as temperature of heating die and pulling speed have been fixed from thermal analysis results. Hybrid composites with various carbon fiber content were manufactured and flexural modules of each hybrid composite as measured. Compare with rule of mixture, positive hybrid effect was observed.

안와저골절 환자에서 구강외과와 안과의 공동 치료

박길선,오세오,김경원 충북대학교 의과대학 충북대학교 의학연구소 1996 忠北醫大學術誌 Vol.6 No.1

안와저 골절을 동반한 다발성 악안면부 골절 환자에서는 외상의 범위가 여러 임상과의 전문영역에 모두 관련되는 경우가 많아서 만족할 만한 수술적 치료 결과를 얻기위해서는 이들 여러분야 전문의들의 협력이 필수적이다. 저자들은 본원의 여러 분과가 관련되어 있는 악안면부의 다발성 골절 환자에 대해, 각 과가 각각의 치료를 하였던 경우와 구강외과와 안과가 공동으로 치료하였던 결과를 비교하여 악안면 외상 치료에 있어서 관련 임상과들의 team approach의 중요성을 확인하였다. Complicated blow-out fracture involving the multiple bones should be examined and treated by team approach incorporatimg the aid of an ophthalmologist, an oral & maxillofacial surgeon, an otolaryngologist, and a neurosurgeon. We compared the surgical treatment of two facial bone trauma cases involved with the orbital floor fracture by different approach. Surgical treatment of complicated blow-out fracures with a team approach was more effective than single department oriented approach.

TMS320F240을 이용한 PWM 인버터 유도전동기 구동 시스템의 전도노이즈 저감을 위한 스위칭 기법

朴奎炫,金利勳,元忠淵,金奎植,崔世琓,咸年根 성균관대학교 2003 학술회의지원논문목록집 Vol.2003 No.-

PWM 인버터에 의해 구동되는 유도전동기에 발생되는 고주파 커먼 모드 전압은 전도성 EMI, 전동기 접지전류, 베어링 전류 및 다른 원치 않는 결과의 주원인이 된다. 인버터 제어의 무효벡터 스위칭 상태는 나머지 유효벡터 스위칭 상태에 비교하여 큰 커먼 모드 전압을 일으킨다. 그러므로 이 논문은 커먼 모드 전압을 완화하는 스위칭기법을 다룬다. 즉 정현파 PWM기법을 기본으로 한 커먼 모드 전압 제거방법을 제안하였다. PWM 신호는 각각의 정현파 기준신호와 120˚위상차가 나는 3개의 캐리어 파형과 비교하여 발생된다. 시뮬레이션과 실험적결과는 제안된 PWM 기법에서 커먼 모드 전압이 종래의 PWM 기법보다 약 66% 더 저감됨을 보였다. High frequency common mode voltage produced by PWM inverter fed induction motor is a major cause of conducted EMI. creation motor ground currents, bearing currents and other hamful products. The zero switching states of inverter control invoke large in comparison with the non-zero switching state of inverter control. We proposed a common mode voltage reduction method based on sinusoidal PWM technique. PWM signal are generated by comparing respective sinusoidal reference signal with three triangular carrier wave displaced of 120˚. Simulation and experimental result show that common mode voltages in the propsed PWM technique are reduced by approximate 66% more than conventional PWM technique.