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.

강 봉 맞대기 용접부의 피로 및 파단 특성

이용복 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

SM45C steel rods using generally for machine components was selected and welded by butt-GMAW method for this study. And then it was studied about characteristics of fatigue behavior and fracture surfaces by rotary bending test. Fatigue strength in weld zone presents highly in order of the boundary between deposited metal zone and heat affected zone, deposited metal zone, heat affected zone. The region of infinite life by Haigh diagram presents highly in order of the boundary between deposited metal zone and heat affected zone, deposited metal zone, heat affected zone. Fatigue cracks in unnotched specimens of base metal and weld zone introduces simultaneously from extensive out-side of circumferential cross-sections and propagates to the other side indicating beach markings and dimples according to consolidation of fatigue cracks. Fatigue cracks in all of notched specimens introduces simultaneously in out-side of circumferential cross-sections by high stresses and propagates to center of it indicating beach markings.

복합비타민 유제의 제조와 평가

이문석,조혜영,이용복 전남대학교 약품개발연구소 2002 약품개발연구지 Vol.11 No.-

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%, v/v), 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 ㎛ 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.

고능률 소형 전자석에 의한 자왜 및 자기이방성 측정

이용호,신용돌,김병걸,민복기,송재성 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.17 No.-

자왜 또는 자기이방성의 측정에 사용되는 전사석의 여자전류를 측정에 필요한 수초간만 흘려서 에너지 소모 및 측정시의 최대난점인 시료의 온도변화의 문제를 극소화하였다. 따라서 전자석의 냉각장치는 생략되고 크기와 전원의 용량도 극소화되었다. 공기간격 22㎜, 자극의 단면적 40 × 25㎟에서 0.5 T의 자장발생에는 180 W의 전원으로 족하였다. 시료의 자왜와, 자기이방성에 의한 토크를 전기용량센서에 의하여 측정하여 10^-8의 자왜분해능과 1 nJ의 토크 분해능을 얻었다. 0.02× 0.8× 10㎟의 연자성 리본의 형상이방성을 이용하여 이방성 측정시의 토크값을 교정하였다. A high efficiency small electromagnet(22㎜ air gap and 40 × 25㎟ core's cross section) suitable for measuring magnetostriction and magnetic anisotropy was built. The magnet could be miniaturized by reducing the measuring space and time. The excitation current of the electromagnet was supplied for only a few second of small. An 0.5 T magnetic field was generated with 180 W power consumption. The values of magnetostriction and magnetic anisotropy were measured with a very sensitive capacitance cell with resolution of 10^-8 and 1 no. The torque was calibrated using a soft magnetic ribbon's shape anisotropy.

SICM616鋼 熔接部의 疲勞龜裂傳播速度에 있어서 殘留應力의 效果에 關한 實驗的 硏究

李龍福,金豪敬 弘益大學校 1984 弘大論叢 Vol.16 No.2

The following conclusions can be drawn from comparisons of fatigue crack growth rates in the weld metal and base metal of high strength steel. 1. Crack growth rates in weld metal are slower than those in base metal at low ΔK. 2. Crack growth rates in weld metal and base metal are almost identical at R=0.5. 3. The lower the stress ratio, the higher the residual stress effect, and higher stress ratio cause greater residual stress relaxation.

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.-

Al 2024-T4 熔接部의 殘留應力이 疲勞破壞擧動에 미치는 影響

李龍福,金鐘鉉 弘益大學校 1986 弘大論叢 Vol.18 No.2

Fatigue fracture behaviors were investigated by using the TIG welded aluminum alloy such as high-strength Al2024-T4 which are widely used in aero-space industry. The fatigue crack propagation was closely examined in both from tensile residual stress region towards compressive residual stress region and from compressive residual stress region towards tensile residual stress region. The experimental results are summarized as follows: 1. In case of fatigue crack propagation from tensile residual stress region, the values predicted by the Forman equation were found to be exactly corresponded to the experimental values. 2. In case of fatigue crack propagation from compressive residual stress region, the Forman equation was found improper to apply directly, but the equation was found proper, if the stress ratio was modified to zero. 3. It was found that crack propagation speed at tensile residual stress region was greater in restrained welding than in unrestrained welding, While crack propagation speed at compressive residual stress region was the same, both restrained welding and unrestrained welding.

SM45C鋼 熔接部의 殘留應力에 依한 疲勞破壞擧動

李龍福,金鍾鉉,金相準 弘益大學校 1987 弘大論叢 Vol.19 No.2

Fatigue fracture behaviors of submerged arc welded SM45C steel were investigated when a crack propagated from tensile residual stress region. The experimental values were compared with the values expected by the Forman equation. The results are summarized as follows: 1. When the fatigue crack was propagated the experimental values were found to corresponded to the values predicted by Formane quation. 2. The experimental values in weld metals have a little difference to the values expected by Forman equation. It was assumed that residual stresses were relaxed by repeated tensile loading. 3. The higher stress ratios were, the larger the difference of fatigue crack growth rate always were in the Same stress intensity factor range for each stress ratios. Particularly, these differences of fatigue crack growth rates were smaller in weld metal than in base metal. It agrees with the fact of that the difference of .effective stress ratios for each stress ratios is small.

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.

정책북한의 대외교역 구조적 특징

이원복,이용삼 국제무역학회 2001 국제무역연구 Vol.7 No.2

북한의 대외경제정책은 국가독점의 원칙, 자급자족경제의 원칙에 입각하여 자립경제 건설의 완성을 위한 보조적 수단으로 간주해 왔으므로 무역의존도는 높지 않았다. 따라서 자립적 민족경제 건설을 상위개념으로 경제발전에 꼭 필요한 상품을 수입하고 그에 필요한 외화를 얻기 위해 상품을 수출하는 것을 기본으로 하고 있다. 그러나 사회주의권의 붕괴로 대외경제협력의 기반이 상실돼 대외무역액이 급격하게 감소하게 되고 북한의 주요 원조국이었던 러시아와 중국마저 구상무역에서 경화결제로 전환함에 따라 북한은 대외무역의 중요성을 점차 인식하게 되었다. 북한은 이러한 경제난을 극복하기 위하여 개방과 개혁을 통한 대외관계 개선으로 교역규모를 확대하고 있다. 북한의 대외교역 규모는 2000년도에 전년대비 33.1% 증가하여 북한경제의 회복을 보여주고 있으며 교역상대국의 다변화를 위하여 노력하고 있으나 수출입물자를 수송할 인프라구축이 열악하여 수송이 용이한 아시아, 유럽과의 교역이 98.5%로 지역별 편중이 심한 무역구조를 가지고 있다. 국가별로는 중국, 일본이외에 태국, 인도 등의 동남아시아 국가들과의 교역이 급속히 증대되고 있다. 그리고 북한의 주요수출상품은 섬유, 전기·전자, 기계류, 수산물, 비금속, 광물, 플라스틱, 농임 산물 등이며 주요수입상품은 기계 및 전기·전자, 섬유, 에너지물자, 식량, 운송기기, 플라스틱, 화학공업제품 등으로 구성되어 있다. This paper represents the structural characteristics on foreign economic policy of North Korea by analyzing the status of trade and relations with foreign countries. The trade dependence of North Korea has not been high until 1980's before destroying socialism system since they import only necessary commodities for building self-economy. However the economic conditions of North Korea have the experience of minus growth and serious difficulties economically which is caused due to inefficient economic policy and due to destroying socialism system. Therefore this paper analyzes the current status of trade and structural characteristics of North Korea to understand how they are going to overcome their difficulties economically by opening economy positively.