AWS ER70S-6, 1.2mm 솔리드 와이어를 사용하는 가스금속아크용접(Gas Metal Arc Welding)에서 작업자의 용접흄 및 금속 폭로에 영향을 주는 요인

정재열,김정만,김용규 동아대학교 부설 산업의학연구소 1997 산업의학연구소 논총 Vol.- No.3

CO₂용접을 대상으로 용접자세, 용접전류 및 헬멧에서 아크까지의 거리 등에 따라서 작업장에서 발생하는 용접흄과 금속에 대한 폭로농도를 파악하여 폭로에 영향을 줄 수 있는 요인을 밝히고자 본 연구를 수행하였다. 중장비 제조업체에서 직경 1.2mm 솔리드 와이어(AWS ER70S-6, BS A18, JIS YGW12)만을 이용하여 CO₂용접을 하는 작업자 95명(전자세 작업자 34명, 아래보기와 수평자세 30명, 위보기와 수직자세 31명)을 대상으로 수행하였다. 연구결과를 요약하면 다음과 같다. 1. 아래보기와 수평자세에서 용접흄의 폭로농도는 15.83mg/㎥으로 가장 높았고, 용접전류도 257.83암페어로 가장 높았으며 헬멧에서 아크까지의 거리 또한 44.87cm으로 가장 멀었다. 2. 철, 망간, 구리, 아연의 금속 폭로농도는 아래보기와 수평자세에서 각각 5.254mg/㎥, 0.849mg/㎥, 0.072mg/㎥, 0.048mg/㎥으로 가장 높았다. 용접흄의 폭로농도가 높을 수록 용접 와이어 그리고 일부 금속은 모재에 함유되어있는 성분이 금속 폭로에 영향을 주었다. 3. 전자세에서 용접흄의 폭로농도와 용접전류사이의 상관관계가 r=0.93으로 가장 높았고, 아래보기와 수평자세에서 용접흄 폭로농도와 헬멧에서 아크까지의 거리사이의 상관관계가 r=0.39으로 가장 높았다. 용접자세에 따른 용접흄 폭로농도에 있어 헬멧에서 아크까지의 거리보다는 용접시 이용되는 용접전류가 더 큰 영향을 주었다. 4. 아래보기와 수평자세에서 공히 용접흄의 폭로 농도가 높을 수록 용접 와이어의 성분인 철, 망간, 구리, 아연의 폭로농가 높은 경향을 보였다. 5. 용접자세에 따른 금속의 복합영향에 있어서 용접자세에 따라 다소 차이가 있었으나 용접 와이어에 함유되어있는 주성분인 철, 망간, 구리가 복합영향에 대한 기여도가 큰 경향이 있었다. 6. 3 개군 모두에서 용접흄의 폭로농도가 높을 수록 복합영향도 높은 경향이 있는 것으로 나타났다. CO₂welders(n=95) using AWS ER70S-6, 1.2mm diameter solid wire were examined and 95 CO₂welders were consisted of 34 all position, 30 downward & horizontal, and 31 overhead & vertical welders. To measure personal exposure for welding fumes and metals, full-period consecutive sampling was used. The results were as follows : 1. Welding fume exposure of 15.83 ㎎/㎥ , welding currents of 257.83 ampere and helmet-to arc distance of 44.87㎝ in downward & horizontal position was the highest and the longest of the three welding positions. 2. Metal exposures of iron, manganese, copper, zinc in downward & horizontal positions were the highest of the three welding positions and the concentrations were 5.254 ㎎/㎥, 0.849 ㎎/㎥, 0.072 ㎎/㎥, 0.048 ㎎/㎥, respectively. 3. Correlation coefficient of 0.93 between welding fume exposures and welding currents in all position was the highest of the three welding positions and correlation coefficient of 0.39 between welding fume exposures and helmet-to arc distances in downward & horizontal positions was the highest of the three welding positions. According to welding fume exposures by welding positions, welding currents had more effect than helmet-to arc distances. 4. Increasing welding fume exposures in downward & horizontal positions, metal components of iron, manganese, copper in welding wire and especially, zinc of base metal were observed. 5. Combined effects of metals by welding positions were some differences but iron, manganese, copper of welding wire major components were the trend that contributes to combined effects(CE). 6. Increasing welding fume exposures in 3 welding positions, combined effects were also high.

김치축제 행사에 관한 평가 연구

정강환,노용호,김현덕 한국식생활문화학회 2004 韓國食生活文化學會誌 Vol.19 No.6

The purpose of this research was to investigate the satisfaction of visitors of Kimchi food festival in 1999, 2000, and 2003. This is the longitudinal study on the cultural festival which used Kimchi as the main resource. This study also investigated the possibility of Kimchi festival as a foreign tour product. This study has several important findings including as follows; First, the satisfaction of residents was higher than domestic visitors in most programs. Second, there were many foreign visitors to the festival and the satisfaction of foreign tourists was higher than residents and domestic tourists. More programs for the foreign visitors are recommended to be an international food festival. Third, experience based food tour events were popular. Introducing more experience oriented programs are recommended for this festival. Fourth, There should be more improvement on food price and parking.

수치표고모델의 자동생성에 의한 수치정사사진제작

박운용,이인수,김정동 동아대학교 건설기술연구소 2000 硏究報告 Vol.24 No.1

This study deals with the product of digital orthophoto using DEM(Digital Elevation Model) from the Digitizer and from the Digital Phtogrammetric Workstation using GCP(ground control points), TP(tie points), and elevation match points each. Interpretation accuracy of the configuration of the earth of the orthophoto from Digital Photogrammetric Workstation is comparatible to that of the orthophoto obtained from the conventional Stereoplotter. So it will be expected that this method are very effective to the fast upgrade of GIS database, and road design, etc.

원자력발전소의 발전설비 정비 표준화를 통한 통합 정비 시스템 개발

석용태,노재정 경성대학교 생산기술연구소 1997 생산기술연구지 Vol.4 No.-

The purpose of this study is to develop an integrated maintenance system which can improve the efficiency of maintenance of the power generating system for nuclear power plant. Standardization of maintenance processes is established and, as a result, the process is broken into 18 dissembly steps and 14 assembly steps. All the related information, such as detailed working procedure, reference data, tool/equipment list, required man power, etc, are integrated to each steps. Appling this integrated system, it is expected that set-up time and maintenance cost can be reduced, through the elimination of unnecessary resources input.

光彈性實驗에 依한 直四角形板材內의 Single Edge Slant Crack에 대한 應力擴大係數 K_Ⅰ,K_Ⅱ 解析

崔鎔湜,李正浩 成均館大學校 科學技術硏究所 1986 論文集 Vol.37 No.1

In this paper, stress intensity factor(K) of single edge slant crack in the rectangular plate subjected to the uniaxial loading was determined by photoelastic experiments. The results were compared with those numerically analysed. In analysing photoelastic fringe loop, the linear slope method which was developed by D, G. Smith was used. The following conclusions were obtained from the experiments. 1. The linear slope method(L. S. M) in photoelastic fringe analysis is applicable effectively when the fringe order is over the third one. 2. K_Ⅰ values obtained from the L. S. M. are in good agreement with those from numerical analysis, K_Ⅱ values are generally higher slightly than those from numerical analysis. 3. When λ(= a/W) is in the range of 0.2 ∼ 0.7, S. I. F. K_Ⅰ, K_Ⅱ and k_Ⅰ, k_Ⅱ increase with the increase of γ in the entire range of slant angle θ. But as θ is 45° and λ is 0.3, k_Ⅰ)_Smith decreases with the increase of λ. When θ is 60° and λ is larger than 0.4, k_Ⅱ)_Smith decreases with the increase of λ. 4. It is found that, in the entire range of slant angle θ, the relative differences between K_Ⅰ)_Smith, k_Ⅰ)_Smith and those after C. E. Freese are around 7%∼25%, and the relative differences between K_Ⅰ)_L.S.M., k_Ⅰ)_L.S.M. and those after C.E. Freese are around -10%∼10%. The relative differences between K_Ⅱ values and those after C. E. Freese are around 5%∼40%. 5. When the slant angle θ is 0°, 15°, or 30° the increasing rates of K_Ⅰ, k_Ⅰ are greater than those of K_Ⅱ, k_Ⅱ. When θ is 45° the increasing rates of K_Ⅰ, k_Ⅱ are similar to those of K_Ⅱ, k_Ⅱ. When θ is 60° the increasing rates of K_Ⅱ, k_Ⅱ are greater than those of K_Ⅰ, k_Ⅰ. 6. In the entire range of slant angle θ, K_Ⅰ decreases with the increase of θ, and the maximum value of K_Ⅱ is obtained when θ is 45.

등단면-I형 곡선보의 영향선에 관한 연구

박정용,장병순 釜山大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.53 No.-

단면이 일정한 곡선보의 거동은 ��綢�효과를 고려한 Vlasov 이론식으로 표시할 수 있다. 본 논문에서는 I-형 곡선보에 대한 지배미분 방정식을 유한차분방정식으로 정식화한 후, 단위수직하중 및 단위비틂모멘트가 작용할 때 부재력을 계산할 수 있는 영향선을 구하였다. 실하중에 의한 부재력은 본 연구에서 구한 영향선을 이용하면 쉽게 계산되어 진다. The general behavior of curved girder with constant cross section is formulated by series of differential equations postulated by Vlasov including the warping effects. After shear force, bending moment, pure torsion, warping torsion, and bimoment for curved I-girder in the paper are analyzed by the difference method, the influence lines of them due to unit vertical load an unit torsional moment for it are obtained by using the finite difference method. The internal forces of the curved girder under an actual load can be calculated using the influence line obtained from this study.

인공효소 8-azaflavin이 기질과의 반응성

최종정,이용희,이동환 한국공업화학회 2004 응용화학 Vol.8 No.2

8-azaflavin was synthesized by condensation of 4-amino-3-N-methylamino pyridune and N-methylalloxane. An oxidation-active flavin mimic contributed substantially to flavin chemistry in model systems. One of the ways of exploting oxidation-active flavin mimics could be by introducing electron-withdrawing groups into the isoalloxazine ring thus providing an electron dificient flavin. We report that 8-azaflavin show remarkably high oxidizing activities for the oxidations of N-benzyl-1,4-dihydronicotinamide(BNAH) and nitroalkanes in aqueous solution.

외상 후 뇌 지방색전증 1예

문정미,소정일,김용권,류진호,허탁,서정진,민용일 대한응급의학회 2001 대한응급의학회지 Vol.12 No.2

Post-traumatic fat embolism was first reported by Zenker in 1862, Von Bergmann reported the first clinical diagnosis of the fat embolism syndrome in 1873. Fat embolism has been associated with traumatic or non-traumatic disorders. Fat embolization after long bone trauma is probably common as a subclinical event. The diagnosis of fat embolism syndrome is based on the patient's history, is supported by clinical signs of pulmonary, cerebral, and cutaneous dysfunction, and is confirmed by the demonstration of arterial hypoxemia in the abscence of other disorders. Two different mechanisms cause fat to embolize: direct entry of deposit fat into the blood stream and agglutination of endogenous or exogenous plasma fat. MRI can detect a cerebral fat embolism with a higher sensitivity than cerebral CT. We report a case of post-traumatic cerebral fat embolism without pulmonary involvement, and we present a review of the literature. A 16-year girl had a traffic accident and pelvic bone fracture. Forty eight hours later severe trauma become stuporous without a focal neurological deficit. The patient received supportive therapy, and her condition improved throughout her hospital course. She was discharged with good condition after a 30-day hospital stay.

癩菌 및 其他 9腫의 Mycobacteria 細胞壁抗原에 對한 癩患者의 皮內反應 比較硏究

愼鏞雨,李增壎,李惟信,張友鉉,金道一 大韓癩學會 1982 癩學 會誌 Vol.15 No.1

한국산 자리공 자리공 열매의 적색소를 이용한 식용색소 : Ⅱ. 활성 사포닌을 제거한 색소의 안정성과 가공적성 Ⅱ. Color Stability and Characteristics as Food Colorant of Saponin-Free Pokeberry Pigments

박용석,서지연,황혜정,박기환,윤광로 中央大學校 食糧資源硏究所 2003 食糧資源硏究所 論文集 Vol.15 No.1

우리나라산 자리공 열매의 색소 함량은 산지에 따라 건물 g당 48.56에서 62.16mg으로 천연색소 자원으로 높은 편이였으며 산지간의 격차가 크지 않아 자원성이 좋은 편이었ㄷ. 자리공 열매의 적색소를 absolute ethanol 침전법으로 분획하는 과정에서 활성 사포닌이 95% 이상 제거되며 이 색고 침전물을 silica gel column이나 Sephadex G-25 column으로 정제함으로서 색소의 순도를 높일 수 있었다. Absolute ethanol 처리와 column 정제법을 응용하여 활성 사포닌을 제거 한 실험용 자리공 열매색소 분획 모두 색소 안정성이나 가공적성에서 뚜렷한 차리를 보이지 않았다. 따라서 absolute ethanol만 처리한 색소제품이나 이를 column chromatography로 정제한 색소분획 모두 고순도의 천연색소 첨가물로의 응용 가능성은 분명하였다. 이들 활성 사포닌을 제거한 자리공 열매색소의 색소안정성과 가공적성은 다음과 같이 요약 할 수 있다. 즉, pH 안정범위는 4.8-6.0이었으며, 열에 대한 안정성을 조사한 결과는 4℃에서 45일 저장했을 때는 70%의 색소 잔존율을 나타낼 정도로 안정한 편이었지만 25℃에서는 10일째에서 70% 잔존율을, 50℃이상의 온도에서는 수 시간 정도에서 50%이하의 색소 잔존율을 보여 전반적으로 열 안정성은 불량한 편이었다. 한편 이들의 존재 하에서는 급격한 변색이 진행되었다. 자리공열매 색소에 대하여 ascorbic acid나 palmityl ascorbate의 첨가는 색소 잔존율에 큰 영향을 미치지 않았으며 chlorogenic acid, resocinol 그리고 catechin의 첨가도 마찬가지였다. 포도당, 과당, 맥아당, 설탕, 펙틴, 셀루로스 그리고 cyclodextrin 등의 탄수화물도 전혀 영양을 미치지 않았다. 1000ppm 이내의 EDTA나 citric acid, malic acid 또는 oxalic acid 등의 산도 미치지 않았다. 금속이온으로서, Ca^(2+)과 Al^(3+)의 첨가는 색소의 잔존율에 큰 영향을 미치지 않았으나, Cu^(2+)나 Fe^(2+)의 첨가는 심한 변색을 초래하였다. 자리공 열매즙의 무수 알코올 처리물(적색 색소 침전물)은 soft gel, firm gel 또는 캔디 등의 고형 식품에 잘 어울리고, 음료에서는 변색이 빠르게 진행되며, 특히 요구르트의 경우가 가장 민감하였다. 결론적으로 보면, 우리나라산 자리공 열매에서 활성 사포닌을 제거하고 확보한 색소제품은 사탕무의 betanin과 거의 같은 색소안정성과 가공적성을 보여 줌으로서 사탕무색소 첨가제인 beet red를 대신할 수 있으며 색소의 함량이나 순도라는 관점에서는 훨씬 우수할 것으로 사료된다. To evaluate the basic data on the color stabilities of saponin-free pokeberry pigment products, % remain of pigment were calculated from absorbances of solutions stored at various conditions. The pigment products were estimated to be very stable at pH 4.8-6.0. Thermostability of pH 5.0 solution of pigment products could be kept stable below 4℃. Addition of Cu2+ or/and Fe2+ decreased the % remain of pigment, whereas most food components had no offset the stability of pokeberry pigment. The color changes of some model foods having pokeberry pigment were checked by Hunter color differerence meter for 45 days. In solid foods like gels and candy the changes of color difference were very slower than that of model beverages. Application of pokeberry pigment to soft drink and yogurt were found to be effective at the refrigerated condition.