PBT/ABS 블렌드의 상용화제에 따른 기계적 물성 연구

윤기호,이중희,최재호,Yun, Ki-Ho,Lee, Joong-Hee,Choi, Jae-Ho 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.10

Poly-butylene-terephalate(PBT) can be impact-modified by blending with ABS material. The effects of compatibilizers and ABS content on the mechanical properties of PBT/ABS blend were examined in this study. EPDM-g-GMA and polycarbonate(PC) were used as a compatibilizer. As the GMA content in EPDM-g-GMA increased, the tensile strength of PBT/ABS blend increased and the impact strength decreased. With increasing the EPDM-g-GMA content in PBT/ABS blend, the tensile strength and impact strength decreased. With PC compatibilizer, the particle size of ABS in PBT/ABS blend became smaller than that of the blend without compatibilizer and the particles were more evenly dispersed in matrix. The maximum impact strength of the PBT/ABS blend was observed in the range of 20~30% ABS content.

Vibrio fluvialis에 의한 균혈증 1예

윤기호(Ki Ho Yun),김정호(Jung Ho Kim),김기방(Ki Bang Kim),윤희정(Hee Jung Yoon) 대한임상노인의학회 2010 대한임상노인의학회지 Vol.11 No.2

Vibrio fluvialis는 바닷물 또는 해산물에서 발견되는 호염성 그람음성 간균이며 주로 설사 및 위장관염을 일으킨다. 저자들은 71세 남자가 2주 전 해산물을 먹은 후 V. fluvialis에 의한 균혈증으로 내원한 드문 증례를 경험하였기에 보고하는 바이다. 그는 발열을 주소로 내원하여 혈액배양 검사에서 V. fluvialis가 확인되었고 수액 및 항생제 치료로 호전되어 내원 11일째 퇴원하였다. Vibrio fluvialis is a halophilic gram-negative bacilli usually found in sea water or seafood, and mainly cause gastroenteritis and diarrhea illness. We present a rare case of bacteremia caused by V. fluvialis in 71-years old man who has a history of sea food ingestion 2 weeks ago. He was admitted because of fever and V. fluvialis was isolated from blood. The patient was cured with fluid and antibiotics therapy and discharged after 11 days.

컨베이어 추적을 위한 로보트 매니퓰레이터의 임의의 경로에 대한 최소시간 궤적계획

윤기호(Ki-Ho Yun),정선태(Sun-Tae Chung) 대한전기학회 1995 대한전기학회 학술대회 논문집 Vol.1995 No.7

슬롯결합을 이용한 발진기형 능동 안테나의 설계 및 제작

문철,윤기호,장규상,박한규,윤영중,Mun, Cheol,Yun, Ki-Ho,Jang, Gyu-Sang,Park, Han-Kyu,Yoon, Young-joong 한국전자파학회 1997 한국전자파학회논문지 Vol.8 No.1

본 논문에서는 능동 위상배열안테나(Active phased array antennas)의 구성소자로 사용될 수 있는 슬롯결합을 이용한 발진기형 능동안테나를 설계, 제작하였다. 배열 안테나 특히 평면 배열 얀테냐에 적합한 급전구조인 슬롯결합을 이용하여 방사소자와 능동회로룹 각각의 기판에 제작한 후 접지면의 슬롯을 통하여 전자기적으로 결합하였다 이와 같은 구조는 배열 안테나로 구성할 경우 단일 평면상에 안테나와 발진회로를 집적하는 구조에서 발생하는 안테나의 협대역 문제, 능동회로에 의한 기생방사, 집적의 문제 등을 해결할 수 있을 것이다. 본 논문에서 설계, 제작한 발진기형 능동안테나는 FET의 드레인 바이어스 전압을 조정하여 발진 주파수를 12.5 GHz를 중심으로 12.37 GHz에서 12.65 GHz까지 280 MHz (2.24%)의 주파수 범위를 선형적으로 조정할 수 있었다. 또한 주파수 가변범위 내에서의 출력이 5 dB 이내의 차이를 가짐으로서 거의 일정하였다. 따라서 본 논문에서 설계, 제작한 능동 안테나를 선형이나 평면의 능동 배열 안테나 소자로 사용할 수 있을 것이다. In this paper, the oscillator type active antenna used as an element of active phased array antenna is designed and fabricated using slot coupling. The radiating element and active circuit are fabricated on each layer respectively and coupled electromagnetically through slot on the ground plane. This structure can solve the problems such as narrow bandwidth of microstrip antenna, spurious radiation by active circuits, and spaces for integration of the feeding circuits which are caused by integrating antennas with oscillator circuits in the same layer. The active antenna in this paper, the oscillation frequency can be tuned linearly by controlling the drain bias voltage of FET. The frequency tuning range is between 12.37 GHz to 12.65 GHz when bias voltage is varied from 3V to 9V, thus frequency tuning bandwidth is 280 MHz (2.24%). The output power of antenna is uniform within 5dB over frequency tuning range. Therefore this active antenna can be used as an element of linear or planar active phased array antennas.

발진기의 2채배 고조파 주파수 천이를 이용한 생체신호 측정센서

구기영(Ki-Young Ku),홍윤석(Yunseog Hong),이희조(Hee-Jo Lee),윤기호(Gi-Ho Yun),육종관(Jong-Gwan Yook),김강욱(Kang-Wook Kim) 한국전자파학회 2016 한국전자파학회논문지 Vol.27 No.3

본 논문에서는 공진기와 인체와의 거리에 따른 근접 전자기장 변화에 의한 공진기 임피던스의 변화를 토대로 사람의 호흡 및 심박신호를 검출할 수 있는 센서를 제안한다. 제안된 생체신호 측정센서는 패치형 공진기가 결합된 발진기, 발진주파수의 2채배 주파수만 통과시키기 위한 다이플렉서, 증폭기, SAW 필터 및 RF 검출기로 구성되어 있다. 호흡과 심박신호와 같은 인체의 주기적인 움직임은 근접 전자기장 영역 안에서 공진기의 임피던스 변화를 야기하며, 발진기의 주파수를 변화시킨다. 감도를 향상시키기 위해 발진주파수의 2채배 주파수 천이를 SAW 필터의 저지대역에 위치시킴으로써, 제안된 센서의 검출 거리를 2배로 확장시킬 수 있다. 제안된 센서의 측정결과, 최대 40 ㎜까지 호흡 및 심박신호가 안정적으로 측정되는 것을 확인하였다. In this paper, a vital sign sensor based on impedance variation of resonator is proposed to detect the respiration and heartbeat signals within near-field range as a function of the separation distance between resonator and subject. The sensor consists of an oscillator with a built-in planar type patch resonator, a diplexer for only pass the second harmonic frequency, amplifier, SAW filter, and RF detector. The cardiac activity of a subject such as respiration and heartbeat causes the variation of the oscillation frequency corresponding impedance variation of the resonator within near-field range. The combination of the second harmonic oscillation frequency deviation and the superior skirt frequency of the SAW filter enables the proposed sensor to extend twice detection range. The experimental results reveal that the proposed sensor placed 40 ㎜ away from a subject can reliably detect respiration and heartbeat signals.

용접잔류응력을 고려한 STS301L 플러그 및 링 용접부의 피로설계 자동화에 관한 연구

백승엽(Seung yeb Baek),윤기호(Ki Ho Yun) 대한기계학회 2010 大韓機械學會論文集A Vol.34 No.9

가스용접 구조물의 장 수명 피로설계기준(fatigue design criterion)을 결정하기 위해서는 정확한 응력해석과 체계적인 피로강도평가가 필요하다. 그러나 실 구조물로부터 피로설계기준을 결정하는 것은 대단히 어려우므로 구조물의 기계적ㆍ구조적 특성을 만족하는 간편 시편을 만들어서 σ-Nf 관계를 도출하여 피로강도를 평가하고 있다. 그리고 가스용접에 의해 제작된 실 구조물의 피로설계를 위해서는 피로균열발생과 파단 기점이 되는 용접부의 용접잔류응력(welding residual stress)이 고려되어야 한다. 따라서, 본 연구에서는 플러그 및 링 가스용접 이음재에 대한 용접잔류응력을 고려하기 위해 용접 열 사이클(heat cycle)에 의한 비선형 열해석(non-linear thermal analysis)과 열 응력(thermal stress) 해석을 수행하고, 실험 치와 비교ㆍ분석하여 용접잔류응력을 고려한 응력 진폭-피로수명((σa)R-Nf) 관계를 도출하여 자동적으로 피로설계기준을 제시할 수 있도록 하고자 하였다. This paper presents a fatigue design method for plug- and ring-type gas-welded joints, which takes into account the effects of welding residual stress. To develop this method, we simulated the gas-welding process by performing nonlinear finite element analysis (FEA) To validate the FEA results, numerically calculated residual stresses in the gas welds were then compared with experimental results obtained by the hole-drilling method. To evaluate the fatigue strength of plug- and ring-type gas-welded joints influenced by welding residual stresses, the use of stress amplitude (σa)R, which includes the welding residual stress in gas welds, is proposed (σa)R on the basis of a modified Goodman equation that includes the residual stress effects. Using the stress amplitude (σa)R at the hot spot point of gas weld, the relations obtained as the fatigue test results for plug and ring type gas welded joints having various dimensions and shapes were systematically rearranged to obtain the (σa)R-Nf relationship. It was found that more systematic and accurate evaluation of the fatigue strength of plug- and ring-type gas-welded joints can be achieved by using (σa)R.

소화기 ; 대전 지역에서 급성 A형 간염의 유전자형에 따른 임상 특성 고찰

이영우 ( Young Woo Lee ),양현웅 ( Hyeon Woong Yang ),이진아 ( Jin A Lee ),윤기호 ( Ki Ho Yun ),양성은 ( Seong Eun Yang ),이민지 ( Min Ji Lee ),박세영 ( Se Young Park ),김새희 ( Sae Hee Kim ),이향이 ( Hyang Ie Lee ),이윤정 ( Yun Ju 대한내과학회 2011 대한내과학회지 Vol.80 No.5

목적: B형 간염이나 C형 간염 등은 유전자형에 따른 차이가 알려져 있지만, 국내에서 증가하는 IIIA 유전자형과 기존의 IA 유전자형에 의한 간염의 차이가 거의 알려진 바 없다. 따라서 대전 지역에서 발생한 급성 A형 간염의 유전자형에 따른 차이를 알고자 한다. 방법: 2009년 11월부터 2010년 6월까지 급성 A형 간염으로 진단되면서 유전자형이 확인된 81명의 환자를 대상으로 임상적 소견들과 검사실 소견들을 전향적으로 연구하였다. 결과: 평균 나이는 32.6±7.4세이며, 평균 입원 기간은 7.7±2.4일이었다. 직업은 서비스직, 사무직 그리고 교육직이 가장 많았다. 유전자형 간의 급성 간염에 따른 증상들의 종류는 별다른 차이가 없었다. 유전자형에 따른 증상의 빈도는 IIIA 유전자형에서 구토와 설사가, IA 유전자형에서는 복통과 피부 반점이 상대적으로 많았다. 검사실 소견에서는 IIIA 유전자형에서 헤모글로빈의 평균, CRP 평균, AST 최대 수치 평균은 상대적으로 유의하게 높았다. 그리고 AST와 ALT 및 총 빌리루빈 최대 수치들과 INR의 수치가 IIIA 유전자형에서 상대적으로 높게 분포하는 경향을 보였다. 결론: 대전 지역에서 유행하는 급성 A형 간염에서 IIIA 유전자형에 따른 급성 간염은 기존의 IA 유전자형과 차이가 있을 것으로 보이며, 다기관 연구를 통한 심도 깊은 연구가 필요하겠다. Background/Aims: Acute viral hepatitis A is a major health problem in Korea and the influx of genotype IIIA is thought to be one reason. We examined the differences in the clinical characteristics and laboratory findings of genotypes IA and IIIA in Daejeon. Methods: From November 2009 to June 2010, 81 patients positive for IgM anti-HAV were enrolled prospectively. The hepatitis A was genotyped using real-time polymerase chain reaction. The clinical characteristics and laboratory results were compared on the Results: The mean patient age was 32.6±7.4 years. The mean hospitalization was 7.7±2.4 days. The patient occupation varied. Clinically, vomiting and diarrhea were relatively more prevalent in genotype IIIA than in IA. Abdominal pain and skin spots were relatively more prevalent in genotype IA than in IIIA. The hemoglobin, peak aspartate aminotransferase (AST) level, and C-reactive protein were statistically higher in genotype IIIA than in IA. The distributions of the peak AST, alanine aminotransferase (ALT) and total bilirubin values tended to be perched in genotype IIIA than in IA. The international normalized ratio (INR) tended to be slightly prolonged in genotype IIIA than in IA. Conclusions: Recently, genotype IIIA of acute viral hepatitis A has become prevalent in Daejeon. Hepatitis A genotype IIIA probably causes worse laboratory abnormalities than genotype IA.

환경기업의 마케팅전략과 기업이미지, 시장경쟁수준, 성과의 관계에 관한 연구

윤기호,김성환 東亞大學校 經營問題硏究所 2001 經營論叢 Vol.22 No.-

The purpose of this study is to analyze the marketing strategy of environmental industry in Korea. Throughout the study, the main concept was set up to the marketing strategy and corporate image, market competitiveness, marketing performance of environmental industry in Korea. It is aimed to reveal the relations among marketing strategy and performance, corporate image, and market competitiveness. In the background of the study, there was a need to study the relations with marketing and the corporate orientation of environmental industry in various fields, and proceeded with the study to focus on the relations between marketing strategy and marketing performance, to explain meditating effects of corporate image and market competitiveness between the two variables. This study has the set six hypotheses as follows to reveal the relations with proceeding variables. First, market competitiveness was significantly differentiated by marketing strategy. Second, corporate images was significantly differentiated by marketing strategy. Third, corporate image was significantly differentiated by marketing competitiveness. Fourth, marketing performance was significantly differentiated by corporate image. Fifth, marketing performance was significantly differentiated by marketing strategy. Sixth, marketing performance was significantly differentiated by marketing strategy. And these hypotheses are tested as follows as diagrams. The first hypothesis was accepted by path coefficient of 0.36 and t-value of 6.74, as the market competitiveness was significantly differentiated by marketing strategy. The second hypothesis was rejected by path coefficient of -0.28 and t-value of 3.53, as the corporate image was not significantly differentiate by marketing strategy due to negative orientation of path coefficient. The third hypothesis was rejected by path coefficient of -0.18 and t-value of 3.42, as the corporate image was not significantly differentiated by market competitiveness due to negative orientation of path coefficient. The fourth hypothesis was accepted by path coefficient of 0.31 and t-value of 6.14, as marketing performance was significantly differentiated by market competitiveness. The fifth hypothesis was accepted by path coefficient of 0.62 and t-value of 7.12, as marketing performance was significantly differentiated by corporate image, Sixth hypothesis was accepted by path coefficient of 0.30 and t-value of 6.81, as marketing performance was significantly differentiate by marketing strategy. In conclusion, this study has drawn the results as follows. First, environmental industry has to change old business fields through the restructuring process to new businesses to gain competitive advantage. Second, environmental industry has to enhance the corporate image by holding the low profit contract, and strengthening the research development and market development. Third, environmental industry has to gain the competitive advantage by SWOT analysis to enforce the concentration of the growth potential.

Vitamin C 缺乏으로 因한 筋肉組織의 形態學的變化

尹起湖 中央醫學社 1942 中央醫學 Vol.11 No.2

In recent years it. has been established that, at least in some circumstances, vitamin E is, a necessary factor for the preservation of the integrity of skeletal muscle fibers. This has been demonstrated,: with. study of specific skeletal muscle lesions in vitamin: E-deficient animals. The lesions of skeletal muscle fibers have been demonstrated in a number of species-, of animals, including guinea pigs (Goettsch et al., 1931, . Madsen, 1936, Shimotori et al., 1939, Chor- et al.,, 1939),- rabbits (Goettsch et al., 1931, . Morgulis and Spencer, 1936, Mackenzie and McCollum, 1939, Morris, 1939), goats and sheepp (Madsen et al., 1932), mice (Pappenheimer, 1942),, rats. (Olcott, .1938, Einarson and Ringsted, 1938, Pappenheimer, 1939, -Goettsch and .Ritzmann, 1939), and dogs. (Anderson et al., 1939, Brinkhous and . Warner, 1941).:And-. the lesions of . advanceck vitamin E deficiency were "so strikingly; similar to2 those of plasmocid intoxication and of virus myositis" that the same disorder of some metabolic factor in muscular activity in each disease seemed to be probable. A few investigators (Milhorat et al., 1945; Rabinovitch et al., 1951) have reported suggestive evidence that large amounts of vitamin, E and synthetic alpha-tocopherol are beneficial in polymyositis and in `"menopausal muscle dystrophy." Mackenzie and McCollum (1940) and. Mackenzie (1942) havestudied the effect of alpha-tocopherol in nutritional muscular dystrophy in rabbitsand' the influence on the metabolism of creatine. Furtheromore, Fitch and Dinning (1964) have studied the metabolism of creatine-l- C'4 in vitamin E-deficient monkeys. Sekizima (1941) and Betz (1951) -have demonstrated that the muscular lesions developed in- the animals on vitamin A-free diet resembled in many respects to the findings of muscle dystrophy' due to lack of vitamin E.' -Hitherto, Krakower and Axtmayer (1940), have reported that the muscular lesions studied in vitamin A-deficient rats can be prevented by.-the- administration of alpha-tocopherol and hence are not solely related to the° vitamin A-deficient state: The -muscles . of the trunk and 'extremities of rabbits have been found to degenerate, after -'the administration of massive doses of cortisone. and the pathogenesis was considered by Ellis (1953, 1956). Moreover, Kendal and Hart (1959), Maclean and`Schurr (1959) and Williams -(1959) have pointed out that a reversible myopathy of similar nature with widespread weakness of muscle fibers has been seen in man following the administration of cortisone derivatives. Glaser and 'Stark (1958) have found that potassium deficiency produced a similar lesion in the' skeletal muscle. The lesion differed from that of the cortisone-treated animals in that the myocardium was also affected. But the prolongation of the refractory period, typical of potassium deficiency, was absent in cortisone myopathy. The skeletal muscle lesions produced by vatimin C deficiency were first described by Dalldorf (1929), and in 1941 Sekizima studied comparative observations on changes of skeletal muscles in avitaminosis A,B,2and C. These .studies are few and were 'confined to the skeletal muscle lesions in vitamin C deficiency only. The majority of the studies have dealt mainly with the morphological changes of the muscle in a few types of avitaminosis. And the mechanisms involved in the metabolic relationship between the muscle lesions and avitaminosis is still unknown. Moreover,, very little attention has been paid to the probable mechanism of the development of` the muscle lesions produced by vitamin C-deficiency in guinea pigs. Therefore, a study of the pattern of muscle lesions involved in various experimental conditions -and of the muscle chemical, contents seems to be appropriate and important. Furthermore, there are still very few theories-first, as to the mode of action of the various factors influencing the muscle lesions in avitaminosis, and secondly as to the factors in. progressive muscular dystrophy in human, the cause of which is still unknown. The purpose of, this study is to characterize the. patterns and the. nature of muscle-lesions, in experimental vitamin, C-deficiency in guinea pigs. It seeks to clarify the C-deficiency in relation to potassium deficiency, the administration of cortisone, of vitamin B; of potassium, and of synthetic alpha-tocopherol, and also it demonstrates a factor modifying the changes of water, lipid and potassium in skeletal muscle.