70계열 알루미늄합금 용접부의 피로균열진전 거동과 피로수명 예측에 관한 연구

옹장우,김재훈,정근춘 忠南大學校 産業技術硏究所 1988 산업기술연구논문집 Vol.3 No.1

It has been important to determine life cycle and stress range for the each welded metal under high cycle load control test conditions. In this study, fatigue crack propagation rate for 7017, 7020, 7039 and 5083 alluminum welded alloy was compared with stress intensity factor range linear elastic fracture mechanics. Compact tension specimens were used and crack growth rate da/dN and stress intensity factor range ΔK were analyzed concerning to the R value of 0.1 and 0.3. In order to find out the value of ΔK, ΔK-inceasing test method was applied by the standard fatigue testing method describes in ASTM E647-81. From the result, the stable crack propagation region of 7017, 7020, 7039 and 5083 alluminum welded alloy was applicable to the Paris equation da/dN = C(ΔK)m (C and m are material constants). Constant m decreases and constant C increases with increasing of stress ratio R. Without dependence on materials, the fatigue life and the propagation rate increase, while the gradients of crack propagation rate decrease, whith increasing stress ratio. Fatigue life was observed roughly in the order of 7020 > 5083 > 7017 > 7039, independently on crack propagation direction and stress ratio. The fatigue life is longer when the crack propagation direction of specimen and welded bead are parallel to each other than transverse. The crack propagation rate and the gradient of it are larger in the case of parallel specimen than transverse. The minimum crack length of fatigue life can be estimated through the knowledge of maximum equivalent crack length obtained by using nondestructive test.

부산지역 소방공무원의 폐기능과 호흡기증상

김성훈,김정원,,김종은,손병철,김정호,이창희,장상환,이채관 大韓産業醫學會 2006 대한직업환경의학회지 Vol.18 No.2

목적: 본 연구에서는 소방관 집단의 호흡기 증상과 폐기능을 조사하여 호흡기 질환의 유병 정도를 비교 분석함으로써 소방관의 호흡기 질환과 화재 노출과의 관련성을 규명하고자 하였다. 방법: 2004년 11월 13일부터 동년 12월 15일까지 부산 소재 4개 소방서와 부속 파출소의 남성 소방공무원 699명을 대상으로 폐기능 검사와 호흡기 설문조사를 실시하였다. 호흡기 증상 설문은 BMRC에서 개발한 설문조사표를 이용하였다. FVC, FEV_(1), MMEF 예측치는 Morris의 폐기능 예측식을 사용하여 계산하였고, 폐기능 검사 이상을 판정하기 위하여 미국 NHNES 기준에 따라 정하였다. 폐기능 측정치와 호흡기 증상은 노출유무와 흡연여부로 집단을 나누어 각각 비교분석하였다. 유의수준은 p<0.05로 정하였다. 결과: 폐기능 비교에서 화재노출군이 FVC, FVC%, FEV_(1), FEV_(1)%, FEF_(25%)는 비노출군에 비해 통계학적으로 유의하게 저하되어 있었고, 이를 흡연여부에 따라 층화하였을 때, FVC 와 FEV_(1)은 흡연여부와 관계없이 노출 여부에 따른 차이를 보이나 FVC%, FEV_(1)%, PEFR은 흡연군에서만 차이를 보였다. 폐기능 검사 이상을 비교하면 전체적으로 화재노출군이 비노출군보다 폐기능 이상자의 수가 많았고 흡연군에서 FEV_(1) 이상자의 차이는 통계적으로 유의하였다. FVC, FEV_(1), MMEF를 종속변수로 하여 다중회귀분석을 시행하였을 때, FVC와 FEV_(1)은 부분적으로 화재노출유무와 관련성이 있었다. 호흡기 증상 조사에서 화재노출군은 비노출군에 비해 코막힘, 목아픔, 흉부압박감의 증상의 호소율이 통계학적으로 유의하게 높았으나, 이를 흡연여부에 따라 층화하면 이들 증상들은 경계역의 차이를 보였다. 결론: 이러한 결과들을 종합하면 소방관은 화재진압과정에서 노출되는 많은 호흡기 유독물질로 인해 급성 폐기능 저하와 높은 호흡기 증상 호소율을 보이며, 이는 화재노출 외에 흡연의 부가적 효과가 영향을 미친다고 생각된다. 따라서 폐기능이 저하된 경방군에서 주기적인 폐기능 검사가 실시되어야 하며, 금연과 호흡기 보호구의 철저한 착용이 권장되어야 하겠다. Objective: The purpose of this study was to evaluate the relationship between respiratory disorders and fire exposure by investigating and analyzing the lung function and respiratory symptoms of firefighters. Methods: The health effects of firefighting on respiratory function were investigated in 699 male fire officers in 4 fire departments in Busan by recording respiratory symptoms and measuring lung function. The data were analysed according to fire exposure and smoking habits. Results: Mean spirometric data showed significantly decreased levels in the fire-exposed group (FVC, -0.20 L; FVC%, -4.2%; FEV_(1) -0.21 L; FEV_(1)%, -5.1%; FEF25%, -0.13 L/SEE p<0.05). After stratification by smoking habits, FVC and FEV1 showed a significant difference between groups. The prevalence of spirometric abnormality was greater for the fire-exposed group than for the non-exposed group. Significantly higher prevalences of nasal stiffness (16.7% vs. 10.9%), sore throat (17.7% vs. 14.2%) and chest tightness (6.5% vs. 2.5%) were recorded in fire fighters compared to controls (p<0.05). However, after stratification by smoking habits, the 3 symptoms were showed only marginal differences in the smoking group. Conclusions: This study demonstrated that fire-exposed firefighters generally suffer a decline of lung function and a higher prevalence of respiratory symptoms. These results suggest that the exposure to routine firefighting activity is associated with adverse health effects to the respiratory system.

MPEG을 이용한 저전송률 화상회의 시스템

장경훈,이정훈,최연성,김장형 濟州大學校 産業技術硏究所 1998 산업기술연구소논문집 Vol.9 No.2

In this paper. we implement ITU-T Recommendation H.323 that is multimedia communication system. Video conferencing system is implemented software using RTP. MPEG and G.721 by Visual C++ 6.0 language in Windows-98. Also Video post-office box is implemented. We should prove the result of H.323 through experiment.

전치부 반대교합아동의 발음장애에 관한 음향적 연구

박정삼,손동수,이상훈,김진태,한세현,장기택,김종철 大韓小兒齒科學會 1996 大韓小兒齒科學會誌 Vol.23 No.2

It has widely known for speech problem in patients with malocclusion,but there have been insufficient studies on degrees of serverity.Patients with openbite and CIⅢ malocclusion usually have speech problem.It has widly known that fricative /s/ is pronunciated most abnomally in CIⅢ malocclusion than any other consonant.Therefore 20 childen with anterior crossbite selected for control group.7 sounds such as /사(sa),서(sδ),소(so),수(su),스(sω),시(si),세(se)/ were recorded,and the formants and formants ratio were measured by using Sensimetric Speech Station,which is speech analyzing program in IBM pc. The results were as follows: 1.In anterior crossbite group,F1 of all 7 sounds were significantly higher than normal anterior relationship group(P<0.05). 2.There were no significant difference in F2 between two groups except/소(so),수(su)/(P>0.05). 3.In anterior crossbite group,F2/F1 ratio of all 7 sounds were significantly smaller than normal anterior relationship group(P<0.05). 4.There were no significant difference in accordance with tongue position(P>0.05).

축구포지션별 무산소 운동능력 분석

손장식,정정욱,김종호,임정수,김훈 대구대학교 기초과학연구소 2003 基礎科學硏究 Vol.19 No.3

In this study, the Wingate power test was performed to investigate of the anaerobic power output in soccer players who play in different position. The main purpose of the test was to provide the enhancement of anaerobic capacity which was conducted by comparing and analysing of the Wingate test. This will improve the performance during the soccer games. Seventeen soccer players with three different positions, FW, MF, DF, were recruited, and undertook the Wingate power test, and anaerobic power, peak power output, anaerobic capacity, and fatigue index was analysed. There was a significant effect of a peak power output among positions showing MF>DF>FW (P<.05). MF revealed the highest peak power output at 15 and 30 seconds time points compared to DF and FW. As far as the players' positions were concerned, a relative anaerobic capacity showed a similar results with a peak power output (P<.05; MF>DF>FW). Unlike with these results, the fatigue index in different positions did not show any statistical significant results (P>.05). Based on these results, it was suggested that the systematical training program is required to perform a modern soccer, pressure and total soccer, in MF players. If the physical strength, especially power out, in MF players is enhanced, the results of the soccer games will be also improved.

여수국가산업단지 인근 지역 대기오염물질 농도에 영향을 미치는 요인분석

김민영,변정훈,이영훈,이건영,한지은,이예림,임지현,장봉기 순천향대학교 기초과학연구소 2022 순천향자연과학연구 논문집 Vol.28 No.1,2

Eight monitoring stations in the Yeosu National Industrial Complex will determine the concentration of air pollutants measured every hour in 2019, analyze what factors affect them, and how they correlate with the air pollutant measurements. Six air pollutants (SO2, NO2, O3, CO, PM-10 and PM-2.5) measured at eight monitoring stations around Yeosu National Industrial Complex (Seogang-dong, Wolnae-dong, Munsu-dong, Yeocheon-dong, Deokchung-dong, Hwayang-myeon, Yulchon-myeon, Samil-dong) the measurement data for each hour of the year were downloaded to analyze the concentration by weather condition, time zone, season, separation distance from Yeosu Industrial Complex, and separation distance from Gwangyang Industrial Complex. SO2, NO2, and CO concentrations were significantly higher in winter, significantly lower in summer, and O3, PM-10, and PM-2.5 concentrations were significantly higher in spring. SO2, CO, PM-10, and PM-2.5 concentrations were significantly higher between 10 a.m. and 12 p.m., NO2 concentrations were significantly higher between 7 a.m. and 9 a.m., and O3 concentrations were significantly higher between 13 p.m. and 15 p.m.(p<0.001). The concentration of air pollutants (SO2, NO2, CO, PM-10, PM-2.5) excluding O3 was found to have a negative (-) correlation with weather condition, and in the case of O3, it was found to have a positive (+) correlation with PM-10, PM-2.5, temperature and wind speed. It was confirmed that the concentration of air pollutants emitted from the Yeosu National Industrial Complex differs depending on the season, time and distance to the industrial complex. This study aims to establish measures to minimize health damage to residents living relatively close to the industrial complex and contribute to the establishment of management and response measures according to the properties of substances to reduce the concentration of air pollutants in the future.

40세 이하 관상동맥 질환자에서 장기적 임상 관찰

이승욱,정명호,박종철,박형욱,조상희,김원,김계훈,이상현,강경태,조장현,김남호,김건형,안영근,조정관,박종춘,강정채 全南大醫大 2001 전남의대학술지 Vol.37 No.2

Bortezomib과 Dexamthasone으로 치료한 골수외 형질세포종 4예

백종현,이은영,장리라,손창배,신은경,서정아,이지숙,이호섭,이상민,신성훈,김양수 고신대학교의과대학 2007 고신대학교 의과대학 학술지 Vol.22 No.2

Despite the use of aggressive local and systemic treatment including autologous stem cell transplantation in multiple myeloma, extramedullary recurrences are common and the prognosis of these patients is poor. Many novel drugs such as thalidomide, lenalidomide and bortezomib improve the response of treatment of multiple myeloma, but some reports failed to describe thalidomide has effect in extramedullary plasmacytoma. Recent data report on the successful treatment plasmacytomas with bortezomib in patients with advanced multiple myeloma. We treated 4 relapsed or refractory extramedullary plasmacytomas with bortezomib at our institution. We recognized all these extramedullary plasmacytomas decreased and showed more than partial response. This report lends support to the efficacy of bortezomib in the treatment of plasmacytoma and describes the safe use of bortezomib. Responses may, however, be of short duration. Therefore, despite our limited experience, we propose that bortezomib may be considered a therapeutic option for such patients who have risk of radiation therapy

역류식 충진탑에서 수력학적인 분석과 이산화탄소의 탈착에 관한 연구

楊善惠,崔東勳,지혜미,金恩貞,金彰昊 동아대학교 환경문제연구소 1996 硏究報告 Vol.19 No.1

This study was carried out to interpret hydraulic behavior and CO₂gas desorption in countercurrent packing tower which packed 50 mm plastic Hiflow-ring. The results are as follows: 1. To compare with conventional packing, 50mm Hiflow-ring could save energy because of low pressure drop under high load. 2. As relative error between calculated value and investigated value was less than 6% in the loading point and flooding point we found that we can predict results mathematically which occurres in the packing tower. 3. The unique magnituteds of packing which was used are as follows. C_(L) = 2.1×10^(-4), n = 0.787 so we can predict efficency which occurres.

Research Notes : Production of Ginsenoside-Rg3 from Lipomyces starkeyi Grown on Ginseng-Steaming Effluent

( Jeong Hoon Jang ),( Na Mi Kim ),( Jong Soo Lee ) 한국균학회 2010 Mycobiology Vol.38 No.2