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.

Carbonic Anhydrase Inhibitors가 Lipopolysaccharide에 의해 유도된 골흡수에 미치는 영향

朴亮鎬,車敬石,金世源 단국대학교 치의학연구소 1992 논문집 Vol.4 No.-

To study bone resorption mechanism, effect of LPS on the ^45Ca release from fetal rat ulnae and radii, and effects of carbonic anhydrase inhibitors on the LPS-induced bone resorption in organ culture were studied. Ulnae and radii were removed from 19 day old fatal rats, prelabelled by subcutaneous injection of 200μCi ^45CaCl_2 into their mother on the 17th day of gestation. Radioactivities of ^45Ca released into media were determined after 24, 48 and 72 hours. Effects of LPS and carbonic anhydrase inhibitors were observed by the ratio of % release of ^45Ca between paired control and experimental group. The observed results were as follows : 1. LPS(1㎍/ml) supplemented in media for 72hours increased the ^45Ca release significantly after 48 and 72 hours of culture and LPS(10㎍/ml) increased the ^45Ca release significantly after 72 hours of culture. 2. LPS-induced ^45Ca release was not inhibited significantly by 1mM sulfanilamide but inhibited significantly by 10mM sulfanilamide after 48 and 72 hours of culture. 3. LPS-induced ^45Ca release was not inhibited significantly by 0.1mM dichlorphenamide but inhibited significantly by 1mM dichlorphenamide after 48 and 72 hours of culture. 4. LPS-induced ^45Ca release was not inhibited significantly by 1mM acetazolamide but inhibited significantly by 5mM acetazolamide after 72 hours of culture.

정밀유성치차감속기 설계(1)

박영덕,이종원,오세훈 중앙대학교 생산공학연구소 1993 생산공학연구소 논문집 Vol.2 No.1

로보트나 정밀기계에 사용되는 유성치차 감속기는 적은 백래쉬 값을 가져야 한다. 본 논문에서는 이러한 적은 백래쉬 값을 갖는 정밀유성치차감속기를 설계하는 기법이 연구되었다. 본 논문에서는 유성치차의 간섭에 있어서 involute, trochoid 그리고 trimming 간섭 뿐만 아니라 전위계수와 위치공차의 잘못된 선정으로 인한 치형 절삭 현상이 나타날 수 도 있음을 규명하였다. 또한, 백래쉬와 전위계수와의 관계식을 유도하여 정밀 감속기를 만들기 위한 도면 표기법에서 걸치기 공차에 따른 전위계수 변동과 백래쉬를 명기하는 프로그램을 개발하였다. Planetary speed reducer of robot or precison machine should have small backlash. In this paper, a design method for planetary speed reducer with small backlash is studied. It is found that there are not only three kinds of tooth's interference : involute, trochoid and trimming one, between planetary gear and ring gear, but also tooth cutting due to wrong selection of shift cofficient and position tolerance. An equation relating the backlash with the shift coefficient is derived and a new manufacturing drawing table is given to check the backlash on the planetary speed reducer using computer program developed in this paper.

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.

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.

장시간 불가피한 공복(fasting)후 인체의 내분비 변화 : 삼풍백화점 붕괴 사고후 구조된 3인의 증례 THREE CASES IN COLLAPSE OF SAMPOONG DEPARTMENT STORE

박규남,황주일,박조현,오동렬,이원재,오승택,김세경,김인철 대한응급의학회 1995 대한응급의학회지 Vol.6 No.2

The interactions between nutrition and the endocrine system are more intimate and complex that previously thought. Nutrition modulates secretion and activity of many hormones, as part of the stress adaptation process. Fasting, in particular, produces a number of important changes in the endocrine system, with teleological purpose of helping the body tolerate the lack of food ingestion. These changes are therefore beneficial and protective, although at times they may not appear to be that way. The endocrine changes of fasting mediate the metabolic response. We must emphasize that these changes are completely reversible when appropriate nutrition is established. These changes are as followes: 1) decreased insulin and increased glucagon levels, 2) decreased thyroid effect, 3) decreased sympathetic activity, 4) hypothalamic hypogonadism, 5) decreased growth, 6) altered glucocorticoid secretion and metabolism, 7) impaired mineralocorticoid response, 8) decreased ADH secretion and effect. We experienced three cases of involuntary prolonged fasting after collapse of Sampoong department store. They were released from collapsed field after 11(case Ⅰ), 13(case Ⅱ), 17days(case Ⅲ) respectively. In each case, the endocrine changes of plasma levels were as followes: decrease of cortisol in case Ⅰ, increase of GH in case Ⅱ, decrease of free T3, T3, cortisol and increase of reverse T3, insulin in case Ⅲ. Each one did not show the same endocrine changes of plasma levels. But we think these changes of fasting are beneficial in metabolic response of human.

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.

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.