• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.359-359
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• 2000

Generally, level control in the steam generator of a nuclear power plant is difficulty process control, because the low power operating can lead nonminimum phase characteristics(swell and shrink phenomenon) and flow measurement are unreliable and nonlinear characteristics. This paper presents a framework for solving this problem based on the constrained linear model predictive control and introduces the design of method for the level of the controller in the entire operating power of the steam generator, and compares with conventional PI controller.

• Analytical Science and Technology
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• v.14 no.6
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• pp.516-521
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• 2001

This research was for reducing leachated concentration of hazardous pollutants in bottom ash from municipal solid waste combustors(200 tons/day) of Korea. Lead and copper compounds were selected as main pollutants. For reducing of leachated level, optimal conditions were observed using air oxidation for lead compounds and water washing method for copper compounds. and it was observed stable pH range of bottom ash from analyzing lechated level by pH variation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.2
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• pp.111-117
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• 2001

A cross-sectional study was performed to evaluate associations between lead biomarkers, lead-related symptoms, and ${\delta}$-aminolevulinic acid dehydratase (ALAD) genotype among 598 lead workers and 144 control office workers in storage battery industries, secondary smelting and litharge making industries. Lead inhibits the second enzymes, ALAD, in the heme synthesis pathway. ALAD gene, which codes for one of three isozymic proteins (termed ALAD1-1, ALAD1-2, and ALAD2-2), seems to modify the toxicokinetics of lead. The result as follows; The percents of total workers whose genotype of ALAD1-1 and ALAD1-2 were 88.4% and 11.6%, respectively. The zinc protoporphyrin in blood (ZPP) and ${\delta}$-aminolevulinic acid in urine (ALAU) of lead workers with ALAD1-2 were significantly lower than those of lead workers with ALAD1-1, but there were no significant difference between two genotype for blood lead, age, and work duration. The proportion of ALAD1-2 genotype in control office workers was 13.2%. The proportions of ALAD1-2 genotype of lead workers were 14.0%(their mean air lead level below $0.024mg/m^3$), 10.4%($0.025-0.049mg/m^3$), 11.8%($0.050-0.099mg/m^3$), and 9.4%(above $0.100mg/m^3$), respectively. In the logistic analysis of 15 lead related symptoms, 'arthralgia'(S7) symptom of ALAD1-2 was significantly lower (OR=0.481; 95% CI=0.248-0.932) than that of ALAD1-1, but 'feeling of irritation'(S11) of ALAD1-2 was significantly higher(OR=1.636; 95% CI=1.035-2.586) than that of ALAD1-1 after controlling possible confounder (blood lead, work duration, smoking and drinking habit).

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.25 no.1
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• pp.28-36
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• 2014

Objectives : The goal of this study was to examine the association between zinc and lead level and symptoms of attention-deficit hyperactivity disorder (ADHD) among Korean children. Methods : A total of 89 clinic-referred children participated in the study (ADHD group=45, control group=44). The participants were 5-15 years old, and were mainly from urban areas of Seoul, Korea. ADHD was diagnosed using the Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version. We excluded children with a comorbid psychiatric disorder, medical illness requiring medication, or a prior history of taking ADHD medication. In order to evaluate the severity of ADHD symptoms, parents' Korean ADHD Rating Scale (K-ARS) was used. The ADHD diagnostic system (ADS) was used for evaluation of the severity of inattention and impulsivity. All participants completed the intelligence test and hair mineral analysis. Multiple regression analysis was used to examine the effect of hair zinc and lead levels on the K-ARS and ADS. We measured the predictive ability of the zinc and lead levels using logistic regression analysis. Results : The lead level explained the score for omission errors, commission errors, and response time SD in visual ADS in the ADHD group (adjusted $R^2$=.243, p<.01, adjusted $R^2$=.362, p<.01, and adjusted $R^2$=.275, p<.01), the score for omission errors of auditory ADS in ADHD group (adjusted $R^2$=.407, p<.01) and the entire group (adjusted $R^2$=.292, p<.01). Zinc was significantly explanatory for the K-ARS scores for the entire group (adjusted $R^2$=.248, p<.001) and the ADHD group (adjusted $R^2$=.247, p<.05). Conclusion : These findings suggest a possible role of zinc and lead in ADHD. Lead concentration in hair samples affected the ADS scores, and this was more prominent in children with ADHD. Children with ADHD had a lower zinc concentration in their hair, and the zinc concentration in hair showed negative correlation with the K-ARS score.

• Geotechnical Engineering
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• v.13 no.6
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• pp.123-138
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• 1997

Electroosmotic tests were performed on saturated marine clay specimens contaminated with lead to investigate the efficiency of the electrokinetic technique for removal of heavy metals from the cohesive soils. For this purpose, testing program included variable conditions such as the concentration of lead (500, 5, 000, 50, 000mg/kg), the level of electrical current (10, 50, 100 mA), operating duration (5, 15, 30days), and the application of three dirtferent chemicals for enhancement in efficiency. The pH of inflow and outflow, electroosmotic flow and electrical conductivity during the test, and the pH and the concentration of lead across the specimen after the test are presented. Test results came to the conclusion that the electrokinetic technique was very effective to remove heavy metals such as lead from the contaminated cohesive soil. Adding ecetic acid at the cathod to dissolve the procipitates of lead hydroxide as found to be effective for the enhancement of the efficiency in remediation.

• Journal of Environmental Health Sciences
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• v.14 no.2
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• pp.89-96
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• 1988

This study was carried out to evaluate the concentrations of heavy metal in hair of the inhabitants of Jeon-Ju industrial area. The major findings of this study are as follows 1. The average content of lead in hair of the inhabitants of Jeon-Ju industrial area was 15.06$\pm$ 4.06 ppm and the content of lead of driver's hair showed higher than that of house wives and students, and showed significance statistically ( P < 0.05). 2. The average content of cadmium by occupation in hair of inhabitants of Jeon-Ju industrial area was 0.76$\pm$ 0.21 ~ 0.52$\pm$ 0.16 ppm and the cadmium concentration in hair of driver's showed the highest level among occupations and showed significance statistically (P < 0.05). 3. Lead and cadmium contents in the hair of the inhabitants of Jeon-Ju industrial area showed higher than that of control area residents and showed significance statistically ( P < 0.05 ). 4. The contents between lead and codmium in hair of Jeon-Ju industrial area residents revealed high degree of correlation ( r = 0.7938).

• Journal of Nutrition and Health
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• v.25 no.7
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• pp.569-577
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• 1992

To study the effects of the age and the dietary protein content on Ca metabolism male rats of 1 month 6 month 12 month of age were fed experimental diets containing 5%, 15% or 50% casein for 4 weeks. Food and ca intake were higher in old rats and in high protein groups. The weight ash and Ca contents of femur and tibia were higher in old rats. The higher dietary protein level resulted in higher skeletal weigh ash and Ca contents. But high protein diet(50% casein) lead to reduced bone mineral density(ash/dry bone weight) and Ca density(Ca/dry bone weight) in 1 month old rats. Low protein diet(5% casein) on the other hand reduced the bone growth even though the bone density was higher in this group. The ill effect of low protein diet was not evident in 12 month old rats. Glomerular filteration rate(GFR) and urinary Ca excretionincreased with age and with dietary protein level especially in 12 month old rats. Serum immunoreactive parathyroid hormone(iPTH) level tended to be higher in aged rats but was not affected by dietary protein level except 1 month old rats where 50% protein group showed significantly higher value. This study showed that the dietary protein level seemed to have different effect on Ca metabo-lism in rats of different age., The low bone density in the high protein group of growing rats may be due to the higher iPTH level and increased urinary Ca. The dietary protein level however had no effects on the bone composition in aged rats even though the higher urinary Ca excretion. In conclusion this study suggests that high protein intake from young may lead to less peak bone mass and to increase the bone loss in later years, which would increase the risk for osteporosis.

• Journal of Preventive Medicine and Public Health
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• v.28 no.4 s.51
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• pp.875-884
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• 1995

In order to investigate the level of lead exposure of workers in litharge making industry and to evaluate how lead exposure, personal habit such as smoking and drinking affect the prevalence of lead related symptoms and other study variables, we investigate 114 workers(24 office workers and 90 lead exposed workers) in a litharge making industry. Study variables chosen were blood lead(PbB), zinc protoporphyrin in whole blood(ZPP), Hemoglobin(Hb), hematocrit (Hct), SGOT and SGPT symptom questionnaires which had 15 lead exposure related symptoms were provided to all workers and filled up by themselves and reconfirmed by physician. The results obtained were as follows; 1. The mean value of PbB, ZPP and SGOT in lead exposed group were higher than those of non-exposed group, and there were no differences of means in other study variables. 2. The smoking and drinking rate of study subjects were 65.8% and 71.0% as a whole. Smoking rates were lower in non-exposed group than exposed group, but drinking rate were not. 3. There were no differences of mean values of study variables between smoker and non-smoker in non-exposed and exposed group, but there was a difference of mean value of SGOT between drinker and lion-drinker in lead exposed group. 4. While the symptom prevalence of lead exposed group were higher in neuromuscular category than non-exposed group, those of non-exposed group were higher or same with exposed group in gastrointestinal and general symptom category. 5. The symptom prevalence of smoker were higher than non-smoker regardless of exposure. 6. The symptom prevalence of drinker were only higher in gastrointestinal symptom category than non-drinker. 7. In multiple stepwise regression analysis of lead related symptoms as dependent variable and blood lead, smoking habit, drinking habit and work duration as independent variables, drinking habit contributed to the gastrointestinal symptom category, whereas blood lead and smoking contributed to the neuromuscular symptom category. For the total symptoms work duration and smoking habit contributed significantly.

• Clinical and Experimental Pediatrics
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• v.48 no.9
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• pp.1009-1015
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• 2005

We encountered two children with lead poisoning who were administered herb medicinal pills recommended by their clergyman. These patients presented anemia and severe coliky abdominal pain, but no neurologic symptoms. For this reason, they were initially misdiagnosed with gastrointestinal hemorrhagic disease. However, we got a clue that they took herb medicinal pills. Finally, based on the assay of blood lead level, we made a correct diagnosis of lead poisoning in these patients. These patients underwent chelating therapy. Subsequently, the concentration of blood lead was decreased. Finally, we drew a conclusion that the possibility of lead poisoning must be considered in children who complained of colicky abdominal pain accompanying anemia. Here, we report two pediatric cases of lead poisoning with a review of literature.

• Journal of agricultural medicine and community health
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• v.26 no.1
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• pp.57-64
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• 2001

A 23-year-old female has visited university hospital for abdominal colic and constipation. She took home-made herb pills for 15 days as a traditional remedy for skin eczema. On clinical examinations, conjunctiva was pale, sclera was icteric and lead line was visible on gingiva. Laboratory examinations are as follows; hemoglobin was 8.6g/$d{\ell}$, reticulocyte was 4.2% and there was basophilic stippling of erythrocytes in peripheral blood smear. Blood level of lead was elevated as $69{\mu}g/d{\ell}$. The herb pills contained 3.32% lead, with cumulative dose of lead over 3.2g. The herb pills were manufactured by a 70-year-old man who was not aware of the health hazard of lead. We suppose that he made herb pills with the imported raw materials from China that contained a high percentage of lead.