• Journal of environmental and Sanitary engineering
• /
• v.10 no.1
• /
• pp.66-75
• /
• 1995

This survey is executed about the water quality and improvement measure of Imjin- river. The results are summarized as follows; 1 ) Ammonia nitrogen concentration in tap water was two times higher than drinking water standard. 2) The concentration of BOD in textile wastewater was 235ppm which is higher than wastewater distribution standard and leather wastewater showed high nitrogen concentration. 3) Water quality of the Imjin- river upstream was not in problem but that of Shin- stream showed somewhat high concentration in BOD, COD, and ammonia nitrogen. Especially the detected Cynide compound on the lower of Shin- stream implied seriously polluted condition. 4) The heavy metal in soil of the river bed was not detected but iron, zinc was detected to high concentration. 5) It Is urgently suggested to build more municipal sewage and sanitary treatment plants, and run dredging and river bed rearrangement project. 6) The Construction of the wastewater treatment complexes of relevant industries shall be propelled as soon as possible.

• 한국금형공학회:학술대회논문집
• /
• 2008.06a
• /
• pp.159-162
• /
• 2008

High pressure is involved during injection molding operation specially packing phase. Cracks in the mold are often occurred by high cavity pressure. In this study, structural analysis of mold has been performed using commercial softwares, Abaqus and Ansys, to investigate cause of crack in the injection mold. Structural analysis contains four cases: stress distribution according to the cavity pressure, stress concentration according to the boundary conditions, stress concentration for inter-locking design of mold, and stress concentration for distributed cavity pressure. Through this study it was observed that the locations of stress concentrations were coincident with locations of crack. Robust mold design is being required to withstand high cavity pressure.

• Journal of Environmental Science International
• /
• v.24 no.7
• /
• pp.961-968
• /
• 2015

The production of highly concentrated $PM_{10}$ is in the spotlight as a social issue, and it increases the attack rate of Asthma. This study aimed to analyze the characteristics of concentration and distribution for $PM_{10}$ from 2000 to 2011, and investigate its correlation with the death from Asthma. Furthermore, this study was designed to analyze it by dividing into two cases like including Asian dust and excluding Asian dust because it presented the high concentration when Asian dust was occurred in the spring. This study has found that the annual average concentration distribution of $PM_{10}$ in Seoul was higher in the central area than the peripheral area. The annual average concentration of $PM_{10}$ and death from asthma displayed the tendency to gradually decrease. The correlation coefficient for all period was 0.92(p=0.000), and the correlation was 0.84(p=0.001) in case of remove Asian dust. The monthly average concentration of $PM_{10}$ has increased in the winter and decreased in the summer. The death from Asthma and correlation coefficient for all period was 0.588(p=0.044) and 0.640(p=0.025) in case of removing Asian dust. Although the causes of Asthma had a great diversity, the similar tendency by a factor of $PM_{10}$ meant that the correlation was high.

• YAKHAK HOEJI
• /
• v.40 no.5
• /
• pp.532-538
• /
• 1996

In cancer chemotherapy, it is necessary to control the phamacokinetic behavior of an antitumor drug for effective treatment. Therefore, two 5-fluorouracil derivatives synthesize d with N-a-cyloxycarbonyl derivatives {1-(N-t-butyloxycarbonyl)leucyloxymethyl-5-FU(BLFU) and 1-(N-t-carbobenzyloxymethyl)leucyloxymethyl-5-FU(CLFU)}. prodrugs of 5-fluorouracil, antitumor agent, were loaded into liposome of different lipid compositions. After liposomal drugs were injected intramuscularly, their pharmacokinetics and tissue distribution were assessed. The $AUC_{0{\to}{\infty}$ values were 1.29, 72.50, 85.57, 66.40 and 103.60${\mu}$g.hr/ml for 5-FU, BLFU, CLFU, BLFU- and CLFU-loaded liposome, respectively. 5-FU was distributed to spleen and liver with a maximal concentration after 1 hr and eliminated after 24 hr. But both prodrugs and dimyristoylphosphatidylcholine liposome entrapped prodrugs were distributed to spleen and liver at a lower concentration but maintained for a long time with a relatively high concentration in lung. Especially, liposome-entrapped CLFU was distributed to lung with a maximal concentration after 1 hr and redistributed to spleen increasingly, while the concentration of liposome-entrapped BLFU in lung reached a maximal level after 12 hr.

• International Journal of Highway Engineering
• /
• v.11 no.3
• /
• pp.141-149
• /
• 2009

Objective of this study was to characterize the particle size distribution(PSD) and quantify the pollutant concentration in highway runoff. Runoff samples during two rainfall events at four road sites in Gyunggi-Do were collected and PSD and associated pollutant distribution was quantified. Also, rainfall amount, flow rate, and other pollutants in samples were analyzed. PSDs in each sample were analyzed and compared with temporal trends of other pollutants. High partial event mean concentrations(PEMC) of particulates were observed at the beginning of runoff and rapid decrease thereafter. Other pollution parameters such as turbidity, TSS, BOD, TN, and TP also have similar temporal runoff trend with the PEMC. Especially PEMC was well correlated with total suspended solids(TSS) and turbidity. Cu, Pb, Zn had high concentration both runoff and sediment. Heavy metals in sediment were strongly bound to fine particles that have the large surface area-to-volume ratios.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1434-1437
• /
• 2003

Sometimes open holes are required for the function and the weight reduction of structure and machinery. However, the serious stress concentration occurs because of the geometric discontinuity caused by the holes and cutting section. In this study, it is attempted to obtain the stress concentration coefficients of the inner surface of the hole boundary by changing the position and the shape of holes on the homogeneous isotropic plate. And the effects on the plate are investigated. The results show that the stress level becomes low and the distribution area widens the position of stress concentration changes as the ratio a/b increases and change to a circle. And as the ratio a/l decreases, the stress concentration reduces. As the plate with three holes. the stress $\sigma$$\_$x/ and $\tau$$\_$xy/ of hole 1,3 becomes high, especially $\sigma$$\_$x/ dominant and high.

• Journal of Preventive Medicine and Public Health
• /
• v.21 no.2 s.24
• /
• pp.374-379
• /
• 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).

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.608-611
• /
• 2000

To separate chitosanoligosaccharides easily by size exclusion, an coencapsulating technology of substrate and enzyme was developed. Chitosan and chitosanase were enveloped in this membrane and the product released to medium by size exclusion. The lower limit of the alginate concentration and the agitation speed were 0.5% and 40 rpm, respectively. Membrane thickness and capsules diameter were $10{\mu}m$ and approx. 3.0mm, 1.5mm, respectively. The molecular weight difference by concentration and cps of alginate were of little significance. And also, the molecular weight of distribution according to enzyme concentration was low concentration of enzyme produced high molecular weight of oligosaccharides. At 1.5mm size of capsule, product diffusion rate to outer part was higher than other capsules. The molecular weight distribution of the released oligosaccharides ranged from 1000 to 6000 Da.

• Journal of Environmental Health Sciences
• /
• v.35 no.1
• /
• pp.21-35
• /
• 2009

The Asian dust storms which originated in the deserts of Mongolia and China transported particles to Korea and led to a high concentration of atmospheric particulate matters (PM) of more than $1000{\mu}g/m^3$ throughout the country in the spring, of 2007. Public concern, in Korea, about the possible adverse effects of these dust events has increased, as these dust storms can contain various air pollutants emitted from heavily industrialized eastern China. The objectives of this study were to understand the concentration characteristics of PM as a function of particle size between the Asian dust storm episodes and non-Asian dust period and to consider the mass size distribution of PM in the Asian dust storms and their water soluble ion species on the potential, possible effects on deposition levels in the three regions (nasopharyngeal, tracheobronchial, and alveolar) of the human respiratory system. The size distribution of PM mass concentration during the Asian dust storms showed a peak in the coarse particle region due to the long-range transport of soil particles from the deserts of Mongolia and China, which was identified by HYSPLIT-4 model for backward trajectory analysis of air arriving in the sampling site of Iksan. During the non-Asian dust period, there were two different types in PM size distribution: bimodal distribution when low concentrations of $PM_{2.5}$ were observed, while unimodal distribution having a peak in fine particle region when high concentrations of $PM_{2.5}$ were showed. This unimodal distribution with high concentrations of fine particulate and secondary air pollutants such as ${SO_4}^{2-}$, ${NO_3}^-$, ${NH_4}^+$ was found to be due to the long-range transport of air pollutants from industrialized eastern China. During the Asian dust storms, the mean concentrations of PM that can be deposited in the nasopharyngeal, tracheobronchial, and alveolar region were $128.8{\mu}g/m^3$, $216.5{\mu}g/m^3$, and $89.6{\mu}g/m^3$, respectively. During the non-Asian dust period, the mean concentrations of PM that can be deposited in the nasopharyngeal, tracheobronchial, and alveolar region were $8.4{\mu}g/m^3$, $9.5{\mu}g/m^3$ and $38.5{\mu}g/m^3$, respectively.

• YAKHAK HOEJI
• /
• v.30 no.6
• /
• pp.323-328
• /
• 1986

This paper describes on the distribution of polynuclear aromatic hydrocarbons (PAHs) in various size of atmospheric particulate matter (A.P.M.). A.P.M. in Seoul city were collected on guartz fiber filter according to particle size using an Andersen high volume air sampler from Feb. 1983 to March 1984. And 7 PAHs [benzo(a)pyrene, benzo(k)fluoranthene, benzo(ghi)perylene, benzo(e) pyrene, perylene, chrysene, and pyrene] were analyzed by high performance liquid chromatography. The concentration of A.P.M. showed spring-winter maxima and summer-autumn minia. The A.P.M. was lowest in the concentration at the 1.1~3.3$\mu\textrm{m}$ particulates, and the concentration increased as the particle size increased or decreased. But the concentrations of PAHs increased with the decrease in the particle size, and were predominant in winter. The correlations among the PAHs were high. And there fore, benzo(a)pyrene concentration could be considered as the representive of PAHs.