• Proceedings of the Korean Environmental Health Society Conference
• /
• 2002.04a
• /
• pp.60-63
• /
• 2002

Objectives : To estimate the correlation of blood lead level of families and environmental factors and infer its influence on blood lead levels in the Korean urban area in Seoul Korea. Methods : The study subjects comprised 499 men and 489 women from 366 families and we analyzed the blood lead level using induced coupled plasma/mass spectroscopy and had interviews. Results : The mean blood lead level of men was 3.00 $\mu\textrm{g}$/dL. The stastical analysis of this study used the tool of frequency rate and t-test between blood lead levels of families and environmental factors. Especially father's smoking and dusty workplace environment showed significancy to blood lead levels. Conclusion : There was positive relationship of blood lead level to several environmental factors. These facts show outdoor environment is more influential than home environment.

• Journal of Plant Biology
• /
• v.19 no.4
• /
• pp.107-110
• /
• 1976

This study was carried out to investigate lead contamination in the leaves of roadside trees and the cause of yellow-brown symptom of leaves in Jinju and Daegu city. After the leaves were collected and dried in 105$^{\circ}C$ drying oven from September to October in 1974, the samples were used for analysis of the lead contents in 1976. The roadside trees in the two cities were mostly the four kinds of Ginkgo biloba L., Thuja orientalis L., Platanus orientalis L. var. acerifolia AIT. and Prunus pseudo-cerasus $LINDL{\times}Prunus$ subhirtella MIQ. The lead contents in the leaves of roadside trees in Daegu city was higher than that of Jinju city. The lead contamination of the evergreen trees of roadside was higher than that of the deciduous trees. In Jinju city the site of the highest contents of lead in the leaves was revealed with Jinju station(0.73ppm), the next site was revealed with the road(0.16ppm) between Namgang bridge and Jinju middle school, and the lowest site was generally beside the roads of suburbs (0.07ppm). Because of the low contents of lead in the leaves, it was found that the yellow-brown symptoms of leaves were not caused by the lead toxicity.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11a
• /
• pp.208-211
• /
• 2003

Characteristics of biosorption of lead by marine algae, Laminaria japonica, were examined. The biosorption capacity of lead by L. japonica was achieved up to 30％ of its own weight and proportional to the initial lead concentration. However, the opposite result was shown in different initial weight of biomass. Ion exchange reaction between lead ions and calcium ions was observed on lead biosorption with Ca-Ioaded biomass. Stoichiometric coefficient, which can represent the exchange ratio between metal ions and protons during elution process, was determined as 1.39. Therefore, it was concluded that the reaction between lead ions already attached in biomass and protons in bulk solution was not fully stoichiometric ion exchange relation at elution process.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.103-108
• /
• 2003

In this paper, the current lead for superconducting device is studied by numerical method. The current lead is cooled by surrounded $N_{2}$ gas by natural convection. The heat conduction equation for current lead and boundary layer equation for $N_{2}$ gas must be solved simultaneously. The boundary layer equation for $N_{2}$ gas is highly nonlinear for varied temperature of current lead. So the linearization method is adopted for simplicity. Numerical results using natural convection cooling are compared with the conventional cooling methods such as conduction cooling and vapor cooling methods. The main difference of natural convection cooing is the non-zero temperature gradient at the top of current lead for the minimum heat dissipation into superconducting devices. For the optimized conduction-cooling and vapor-cooling current leads, the temperature gradient at the top of current lead is zero. Also, the heat flow at the cold end is much smaller than conduction cooling case.

• Toxicological Research
• /
• v.19 no.4
• /
• pp.315-320
• /
• 2003

This study was carried out to investigate the effect of chitosan on lead metabolism in SD rats. Ten male rats were divided into a experimental group and a control group. Each experimental and control rats were administered by water contaminated with 100 mg/l of lead for 4 weeks, respectively. Experimental group received diets supplemented artificially with 5% of chitosan for 4 weeks. Body weight change, food and water consumption, fecal and urinary excretion, and fecal and urinary lead excretion were measured. There were no significant differences in body weight gain, food and water consumption, and fecal and urinary excretion between the two groups. However, fecal lead excretion of rats fed the diet containing 5% of chitosan were higher than the control group. Whereas urinary lead excretion of rats fed the diet containing 5% of chitosan were lower than the control group. The results suggested that the oral administration of chitosan prevents the gastrointestinal lead absorption in rats.

• Toxicological Research
• /
• v.1 no.1
• /
• pp.49-63
• /
• 1985

The purpose of this study was to investigate whether or not $VATAMIN B_1$ (thiamin hydrochloride) could prevent and/or treat lead posoning in rats. Sprague-Dawley used in this experiment were divided into three group; control group compound group (thiamin 10mg+0.4% lead acetate solution) lead group (0.4% lead acetate solution). The results obtained were summarized as follow; 1. The body weight gain of treated groups (compound group and lead group) were lowered significantly in comparsion with those of control groups (p<0.01). But the significant difference between treated group was not observed (p<0.05).

• Journal of the Earthquake Engineering Society of Korea
• /
• v.20 no.5
• /
• pp.311-318
• /
• 2016

The lead-rubber bearing (LRB) dissipates seismic energy through plastic deformation of lead core. Under large-displacement cyclic motion, the temperature increases in the lead core. The shear strength of a lead-rubber bearing is reduced due to the heating effect of the lead core. In this study, the seismic responses such as displacement increasing, shear strength and vertical stiffness degradations of LRB due to the heating effect are evaluated for design basis earthquake (DBE) and beyond design basis earthquake (150% DBE, 167% DBE, 200% DBE).

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.12
• /
• pp.2019-2022
• /
• 2016

In the presence of an electrically conducting medical lead, radio frequency (RF) coils in magnetic resonance imaging (MRI) systems may concentrate the RF energy and cause tissue heating near the lead. A novel design for a medical lead to reduce this heating by introducing pins in the lead is presented. Peak 10 g specific absorption rate (SAR) in heart tissue, an indicator of heating, was calculated and compared for both conventional (Medtronic) lead design and our proposed design. Remcom XFdtd software was used to calculate the peak SAR distribution in a realistic model of the human body. The model contained a medical lead that was exposed to RF magnetic fields at 64 MHz (1.5 T), 128 MHz (3 T) and 300 MHz (7 T) using a model of an MR birdcage body coil. The proposed design of adding pins to the medical lead can significantly reduce the heating from different MRI systems.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 1998.10a
• /
• pp.328-334
• /
• 1998

The characteristic tests for the reduced-scale lead rubber bearings are performed with three different diameters of lead plugs. The test frequencies are 0.05Hz and 0.5Hz of the sinusoidal waves. The roles of lead plugs in the behavior of lead rubber bearings are investigated. The shear-deformation characteristic values such as stiffness, damping and yield load values are increased according to the increase of the diameter of lead plugs. The high damping value can be obtained by increasing the diameter of lead plug.

• Journal of the Ergonomics Society of Korea
• /
• v.32 no.3
• /
• pp.259-266
• /
• 2013

Objective: This study aims to evaluate the workloads of industrial and automobile storage battery industries and their association to biological exposure indices. Background: Occupational lead exposure at battery manufacturing workplace is the most serious problem in safety and health management. Method: We surveyed 145 workers in 3 storage battery industries. Environmental factors(lead in air, temperature, humidity and vibration)), biological exposure indices(lead in blood and zinc protoporphyrin in blood) and individual workload factors(process type, work time, task type, weight handling and restrictive clothing) were measured in each unit workplace. Results/Conclusion: Air lead concentration is statistically significant in associations with workload factors(process type, work time, task type, and restrictive clothing) and environmental factors (humidity and vibration), whereas zinc protoporphyrin in blood are significantly associated with work time and weight handling. And lead in blood is significantly associated with work time, weight handling and temperature. Application: The results of this study are expected to be a fundamental data to job design.