• 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 Preventive Medicine and Public Health
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• v.21 no.2 s.24
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• pp.374-379
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• 1988

In order to prepare the fundamental data for preventing the hazardous effects at toluene exposure in many kinds of industry, the authors determined the level of urinary hippuric acid on 592 toluene exposed women(exposed group) and 102 unexposed women(control group) in Pusan area, from April. 1 to October 31, 1986. Hippuric acid was measured by high performance liquid chromatography. The results were summarized as follows; 1. The mean value of urinary hippuric acid concentration of the control group was $0.44{\pm}0.21g/l$(0.11-0.89g/l). The distribution of urinary hippuric acid concentration of the control group was not fit to the normal distribution. 2. The mean value of urinary hippuric acid concentration of the exposed group was $1.56{\pm}0.95g/l$(0.44-4.57g/l). The distribution of urinary hippuric acid concentration of control group was not fit to the normal distribution. 3. The urinary hippuric acid concentration by age group was not statistically significant in the control group, but in the exposed group the urinary hippuric acid concentration was highest in women between 20-29 years old($1.71{\pm}0.95g/l$) and was statistically significant(p<0.01). 4. The urinary hippuric acid concentration by duration of working hours was not statistically significant (p>0.1).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.2
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• pp.240-247
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• 1994

To identify normal levels of ethanol, acetaldehyde and alcohol dehydrogenase(ADH) activity in blood of Koreans, ethanol and acetaldehyde levels, activity of ADH in blood of Koreans, ethanol and acetaldehyde levels, activity of ADH in blood were measured in 97 subjects(male : 36, female : 61), 45 subjects(male : 21, female : 24) were not exposed to organic solvents and any other chemicals. Fifty two subjects(male : 15, female : 37) were exposed to organic solvents including toluene and xylene. The results were summerized as follows : 1. The blood ADH was not detected in exposed and non-exposed group. 2. The average blood ethanol level of non-exposed group was 0.0490 mg/dl, and exposed group was 0.0363 mg/dl. They were statistically significant(p<0.05). 3. The blood acetaldehyde levels in exposed group were significantly higher than that of non-exposed group was not statistically significant (p>0.05). 4. The average blood ethanol level of males in both groups was significantly higher than that of females, however, they were not statistically significant (p>0.05).

• Journal of the Korean Society of Industry Convergence
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• v.22 no.5
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• pp.583-589
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• 2019

One of the core pillars of the Fourth Industrial Revolution is the innovation of the manufacturing industry. From the beginning, the 4th Industrial Revolution appeared in Germany under the concept of 'Industrial 4.0', which means a radical change in the manufacturing industry that can provide super intelligent product production and services based on artificial intelligence and big data. Since manufacturing innovation is a change in the industrial character of the entire nation, the initial role of government is important. Korea also has various policies related to the 4th Industrial Revolution, but there are still various problems to be solved. Therefore, this paper monitors and analyzes the public R&D projects of the advanced countries on manufacturing innovations in the background mentioned above, and through this, the policy implications are drawn.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.2
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• pp.209-223
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• 1998

The aim of this study was to evaluate welders' exposure to hexavalent chromium (Cr(VI)) and nickel (Ni) during welding operations in a Korean shipyard. The airborne Cr(VI) and Ni concentrations were measured during metal inert gas (MIG) welding on mild and stainless steel, and manual metal arc (MMA) welding on mild steel. The geometric mean (GM) of Cr(VI) concentrations inside the welding helmet during MIG welding on mild steel were $0.0018mg/m^3$ inside a ship section, and $0.0015-0.0026mg/m^3$ at the welding shops. All of the personal breathing zone air samples were below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value ($TLV^{(R)}$) of $0.01mg/m^3$. Conversely, eighty-eight percent(21 of 24) of the personal breathing zone air samples exceeded the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit of $0.001mg/m^3$. Ni was not detected on 20 of 23 air samples collected during MIG welding on mild steel. The three Ni samples above the limit of detection ranged from 0.015 to $0.044mg/m^3$. The GM of Cr(VI) concentrations during MMA welding on mild steel were $0.0013mg/m^3$, but Ni was not detected in the air samples during this operation. It is assumed that the airborne Cr(VI) and Ni during mild steel welding were derived from the base metals which contained about 0.03% Cr and 0.03% Ni. The GM of airborne total Cr, Cr(VI) and Ni concentrations during MIG welding on stainless steel were 4.02, 0.13 and $0.86mg/m^3$, respectively, and the levels of Cr(VI) and Ni were above the ACGIH-$TLV^{(R)}$. Cr(VI) comprised about 35.5% of the total chromium(Cr) from MIG welding on mild steel, and about 8.4% of total Cr from MIG welding on stainless steel. The ratios of Cr(VI) to total Cr were significantly different among welding shops. It was concluded that welders were exposed to high levels of Cr(VI) and Ni during welding on stainless steel, and were exposed to low levels of Cr(VI) even during welding on mild steel.

• Journal of Korean Public Health Nursing
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• v.8 no.1
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• pp.63-72
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• 1994

The purpose of this study was to estimate the industrial worker's knowledge, attitude, and practice about occupational health and to provide the basic data for the development of industrial health services. The study was undertaken from January 15 to January 30, 1993. 549 industrial workers at the Industrial Complex located in Chonbuk Province were participated in this study. The results were as follows; 1. The Knowledge, Attitude and Practice leveles of Workers about Occupational Health. The levels were measured by five point scale. The mean score of knowledge was 2. 59 point out of 4. The mean score of attitude was 2.37 point out of 4. The mean score of practice was 2. 38 point out of 4. 2. The analysis of their knowledge" attitude, and practice about general characteristics. 1) There was significant difference among different age groups. $(P{\leqq}0.0001)$ -. The group of age 25-29 was the highest value in knowledge and attitude. -. The group of age over 50 was highest value in practice. 2) There was significant difference between sexual groups in all items. -. Male workers were higher than Female workers in all items. (P=0.0000) 3) There was significant difference according to the marital status in all items. -. Married workers were higher than Single workers in all items. (P = 0.0000) 4) There was significant difference among different groups of educational level in attitude and practice. (P<0.05) The value was positivly correlated to their educational level. 5) There was significant difference among the groups of job-part in knowledge and practice. (P=0.000, P=0.031) -. Office workers were higher than Production workers in all items. 6) There was significant difference among different group of job experience in knowledge and attitude. (P=0.0000. P=0.0387) The value was positively correlated to the years length of job experience. 7) There was significant difference among the groups of different monthly income in all items. (P=0.000) The value was positively correlated to their monthly income.

• The Journal of the Korea Contents Association
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• v.21 no.11
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• pp.528-542
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• 2021

The purpose of this study is to examine the commonalities and differences that appear across the types of perceptions toward job changes according to the Industrial 4.0. among job seekers and workers. For an approach to subjective beliefs, viewpoints and preferences, the data investigated using Q methodology, was analyzed using the QUANL program for PC. From the Q-methodology, the types of perception toward job changes due to Industrial 4.0 and their features were drawn. The perception types were classified as four types: negative perception type, neutral perception type, high evaluation about quality of jobs, and employment increase perception type. The results found that views toward job transition due to Industrial 4.0 are were diverse beyond the dichotomy and institutional and educational efforts should be required to mitigate job insecurity and cope with job changes caused by technological advance.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.355-362
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• 2000

The objective of this paper is to estimate the pollutant load based on event mear concentrations(EMC) in industrial complex. Eight sub-basins in the Chongju industrial complex were selected for sampling and study with different characteristics during the period from June 1997 to August 1998. During the storm events, measured EMC ranges of $BOD_5$, COD, SS, TKN, TP, HEM, $NO_3-N$, $PO_4-P$, Cr, Pb, Cu and Fe in the industrial complex watersheds were 11~176mg/L, 40~502mg/L, 23~633mg/L, 104~20.9mg/L, 0.22~7.51mg/L, 12.7~548.7mg/L, 0.06~2.66mg/L, 0.12~3.39mg/L, 0.01~0.50mg/L. 0.02~0.42mg/L, 0.01~0.15mg/L and 1.29~11.51mg/L respectively. And the calculated annual average pollutant unit loadings of $BOD_5$ COD, SS, TKN, $NO_3-N$, $PO_4-P$, TP, HEM, Cr, Pb, Cu and Fe were 374.4kg/ha/yr 924.1kg/ha/yr, 983.6kg/ha/yr, 48.8kg/ha/yr, 8.1kg/ha/yr, 9.7kg/ha/yr, 17.8kg/ha/yr 943.0kg/ha/yr, 0.7kg/ha/yr, 0.9kg/ha/yr, 0.3kg/ha/yr and 28.9kg/ha/yr, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.5
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• pp.169-174
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• 2022

This study is to verify the feasibility of SiC single crystal growth using recycled SiC powder. The fundamental physical properties such as particle size, shape, composition and impurities of the recycled powder were analyzed, and the sublimation behavior occurring inside the reactor were predicted using the basic data. As a result of comprehensive judgment, the physical properties of the recycled powder were suitable for single crystal growth, and single crystal growth experiments were conducted using this. 100 mm 4H-SiC single crystal ingot with a height of 25 mm was grown without polytype inclusion. In the case of micro-pipe density was 0.02 ea/cm² and resistivity characteristics was 0.015~0.020 ohm·cm², commercial level quality was obtained, but additional analysis related to dislocation density and stacking faults is required for device application.

• Korean Journal of Materials Research
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• v.25 no.1
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• pp.32-36
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• 2015

Hot rolling of Mg-6Zn-0.6Zr-0.4Ag-0.2Ca-(0, 8 wt%)Li powder was conducted at the temperature of $300^{\circ}C$ by putting the powder into the Cu pipe. The microstructure and mechanical properties of the samples were observed. Mg-6Zn-0.6Zr-0.4Ag-0.2Ca without Li element was consisted of ${\alpha}$ phase and precipitates. The microstructure of the 8 wt%Li containing alloy consisted of two phases (${\alpha}$-Mg phase and ${\beta}$-Li phase). In addition, $Mg_2Zn_3Li$ was formed in 8%Li added Mg-6Zn-0.6Zr-0.4Ag-0.2Ca alloy. By addition of the Li element, the non-basal planes were expanded to the rolling direction, which was different from the based Mg alloy without Li. The tensile strength was gradually decreased from 357.1 MPa to 264 MPa with increasing Li addition from 0% to 8%Li. However, the elongation of the alloys was remarkably increased from 10 % to 21% by addition of the Li element to 8%. It is clearly considered that the non-basal texture and ${\beta}$ phase contribute to the increase of elongation and formability.