모 연취급장 근로자들의 연폭로지표들과 혈압과의 관련성

임상복,김용배,이용진,리갑수,김화성,황규윤,장봉기,이성수,안규동,이병국 순천향대학교 산업의학연구소 1998 순천향산업의학 Vol.4 No.1

In order to investigate the relationship between blood lead with other lead exposure indices and blood pressure in occupationally lead exposed male workers, 629 workers(515 lead exposed workers and 114 non lead exposed workers) in a storage battery factory were studied. Blood lead(PbB), zinc protoporphyrin(ZPP) and urinary δ-aminolevulinic acid(ALAU) were selected as an index of lead exposure. Height and weight were also meaured with calibrated automatic height-weight machine to produce fatness index directly. Personal information on smoking and drinking history were also collected. Blood pressure was mearured by trained nurses with automatic sphingomanometer. All workers took at least 30 minute rest before their measurement of blood pressure. The results obtained were as follows: 1. The prevalence rate of hypertension of lead exposed and non-exposed workers were 3.5% in both group without any difference. 2. There were no differences of systolic and diastolic pressure between groups divided by lead exposure, smoking habit, drinking habit. but the increase of age group made the difference of diastolic pressure, and only differenct of systolic pressure observed in age group of less than 20 and that of more than 40. 3. In pearson's correlation analysis, PbB was correlated with systolic pressure significantly, but not with diastolic pressure. PbB was also correlated with pressure difference(systolic pressure-diastolic pressure). 4. There were no significant increase of systolic, diastolic pressure and pressure difference by the increase of PbB and ZPP grouping. 5. Stepwise multiple regression analysis using systolic pressure as dependent variable and PbB, ZPP, ALAU, age, work duration, smoking habit, drinking habit and fatness (weight*0.9/height-100) as independent variables, revealed that PbB, age, drinking habit and fatness in order were significantly contributed to the dependent variable. 6. Stepwise multiple regression analysis using diastolic pressure as dependent variable and PbB, ZPP, ALAU, age, work duration, smoking habit, drinking habit and fatness (weight*0.9/height-100) as independent variables, revealed that ALAU, age and fatness in order were significantly contributed to the dependent variable. 7. Stepwise multiple regression analysis using pressure difference as dependent variable and PbB, ZPP, ALAU, age, work duration, smoking habit, drinking habit and fatness(weight*0.9/height-100) as independent variables, revealed that PbB, age and fatness in order were significantly contributed to the dependent variable. 8. Logistic analysis of hypertensive conditions with categorized blood lead and other selected categorized independent variables indicated that only age(40> and 40≤) and fatness(1.0> and 1.0≤) were significantly contributed to dependent variable with 95% significant odd ratio confidence interval. With above results, lead exposure in terms of blood lead seemed to be minimally contributed to the raise of blood pressure, and the effect of blood lead was found to be more prominent on the pressure difference than the systolic and diastolic pressure themselves.

과학경진대회의 문항과 분석과 학습지도 방안

이용복,배영부 서울교육대학교 과학교육연구소 1996 科學과 數學敎育 論文集 Vol.22 No.-

미용입 십자형 필렛용접부의 기하학적 피로특성

李龍福,金慶燮 弘益大學校 科學技術硏究所 2000 科學技術硏究論文集 Vol.11 No.-

Fatigue failure modes of symmetrical LOP fillet weldments are dependent on the characteristics of the fatigue crack initiation and propagation from the weld toe or the weld root. In this study, constant amplitude fatigue tests on symmetrical LOP fillet weldments carried out, and fatigue properties were evaluated. Also, an attempt was made to develop the fatigue strength and fatigue life of symmetrical fillet weldments containing lack of penetration. From the result of this study, fatigue crack growth characteristics of symmetrical LOP fillet weldments are found to be affected by the weld geometry, stress range and microstructures of the welding zone.

中炭素鋼 熔接部의 熱處理에 따른 機械的 性質에 관한 硏究

李龍福,金柄旭,康仁燦 弘益大學校 1982 弘大論叢 Vol.14 No.2

Strength of the weld zone is influenced by many complicated factors, such as welding conditions, constraint, materials, etc. Especially, Residual Stress plays an important role for mechanical properties in the weld zone. In this paper, the stress relief effect on the residual stress of the weld zone was examined under various annealing treatment. The results obtained are as follows. 1.Tensile strength on welding decreased 5.7%, 11.4% and 15.3% with increased annealing temperature from 650℃ to 850℃. 2.Absorbed lmpact energy increased in turns of Bond Zone, Base Metal, Fusion Zone and H.A.Z(Heat Affected Zone) and decreased with increasing of the annealing temperature 650℃, 850℃. 3.Reisdual Stress on welding was reduced by the ratio of 65%, 82.5%, 90% with the increased annealing temperature from 650℃ to 850℃. 4.It may be concluded that the best result of the annealing was obtained at 650℃.

복합비타민 유제의 제조와 평가

이문석,조혜영,이용복 한국약제학회 2002 Journal of Pharmaceutical Investigation Vol.32 No.1

Water-lipid soluble multivitamin formulations were widely used to reduce the disease and stress of animals as husbandry has made a remarkable progress in recent. But the efficiency of these formulations is far from satisfactory. So, this study was attempted to develop the physically and chemically stable and useful multivitamin o/w emulsion. Multivitamin o/w emulsion composed of water, soybean oil (10%, vlv), vitamin A, D, E, K, B_2, B_6, B_12 and panthenol. To make a stable o/w emulsion, the egg lecithin (2%, w/v) and glycerin (2.5%, w/v) were used for emulsifier and thickening agent, respectively. The oil in water emulsion system was manufactured by microfluidizer and the physicochemical stability of this emulsion was evaluated. The average particle size and interfacial tension were measured. From the result of interfacial tension tested, critical micelle concentration of the egg lecithin was 0.5% (w/v) and optimal concentration for the preparation of emulsion was 2% (w/v). The mean particle size was about 0.6 μm which was suitable for injections. Short-term accelerated stability as physical stability study was tested by centrifuging and freeze-thawing the emulsion samples. The additions of vitamins resulted in the increment of particle size and reduction of physical stability of emulsion. But it is not an enormous problem for the stability of emulsion. Also, we have performed the long-period preservation stability test for the vitamins. All vitamins were analysed by HPLC. The result of storage under 4℃ and dark conditions demonstrated that all vitamins were maintained stable at least 16 weeks, except for vitamin B_12.

朝鮮의 石刻天文圖

李瑢馥 서울교육대학교 과학교육연구소 1997 科學과 數學敎育 論文集 Vol.23 No.-

時變磁界 測定用 센서에 관한 硏究

이복희,백용현,박형기,정승수,전덕규 경북대학교 센서기술연구소 1992 센서技術學術大會論文集 Vol.3 No.1

고정 스트레스 상태의 흰쥐에서 할로페리돌 전처치가 뇌생아민의 대사에 미치는 영향

이수복,양병환,김이영,이용성,고재경,김광일 漢陽大學校 精神健康硏究 1991 精神健康硏究 Vol.10 No.-

熔接部의 熱處理에 따른 殘留應力 및 破壞擧動에 關한 實驗的 硏究

李龍福,鄭 剛 弘益大學校 1983 弘大論叢 Vol.15 No.2

In this study, picking up a mild steel(SS41) of the carbon steel, a spring steel (SUP9) and stainless steel (SUS304) of the special steel, for the experimental materials, these are welded by CO₂(SS41, SUP9), TIG(SUS304), respectively. After that, the residualstress distribution and fracture behavior at the welded zone are examined according to annealing temperature of the four sections involved as weld. Summarizing of the results in this experiment, the following conclusions are obtained: 1. The residual stress distribution of spring steel (SUP9) is very small in comparison with mild steel (SS41) and stainless steel (SUS304) 2. The removed grade of residual stresses are largest when annealed at 900℃(SS41), 850℃(SUP9), 1000℃ (SUS304), respectively. 3. The tensile strength of heat-affected zones are largest when annealed at 800℃(SS41), as welded(SUP9), 900℃(SUS304), respectively. 4. The impact value of heat-affected zones are largest when annealed at 900℃(SS41), 750℃(SUP9), 1100℃(SUS304), respectively. 5. The best annealing temperatures are at 900℃(SS41), 750℃(SUP9), 1100℃(SUS304), respectively. Then, the residual stress is removed enough and mechanical properties are very suitable.

初期 缺陷形狀에 따른 表面龜裂傳播 特性에 關한 硏究

李龍福,金鍾鉉,李錫俊 弘益大學校 1990 弘大論叢 Vol.22 No.2

In this study, the diameters and depths of the intial surface crack configuration on the specimen was discharge processed differently and considered about propagation behavior and fatigue lifetime of the surface fatigue crack in each case. The result of this study are Summerized as follow; 1. Under the given constant condition, aspect ratio is regular in surface crack propagation, and early its differenceis large according to the initial surface crack configuration but it shows the same change aspect according to the propagation of the crack. 2. In general, for constand initial crack depths we may expect that initial crack lifetime is increased as diameter of specimen is increased because of relaxation of the stress concentration. Practically, however it is different according to the crack. 3. Early, Surface crack configuration has semi-circle and it has semi-elliptical according to crack propagation. 4. When the initial surface crack aspect ratio is in the range of 5∼6, the initial surface crack is propagated to inner surface under the condition, which ratio is smaller than the range. In the ratio is lager than that range, crack is propagated to outer surface.