• Membrane Journal
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• v.11 no.4
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• pp.190-203
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• 2001

In this study the discharged wastewater from a paper plant was filtrated by 4 kinds of tubular carbon ceramic ultrafiltration membranes with periodic water-back-flushing. We could investigate effects of watch-back-flushing period, transmembrane pressure (TMP) and flow rate, and find optimal operating conditions. The back-f1ushing time (BT) was fixed at 3 sec, and fi1tration times (FT) werc changed in 15~60 scc, TMP in 1.00~2.50$kg_{f}$/$cm^2$, and the flow rates in 0.27~1.75 L/min. The optimal conditions were discussed in 7he viewpoints of dimensionless permeate flux (J/J$_{0}$), total permeate volume ($V^T$) and resistance of membrane fouling ($R^f$). Optima1 back-flushing period was BT/FT=0.20, suggesting that the frequent back-flushing should decrease membrane fouling. Optimal TMP in the viewpoint of $V^T$ was 1.00~1.55$kg_{f}$/$cm^2$, suggesting that rising TMP should increase membrane fouling and decrease permeate flux. But, rising f1ow rate should decrease membrane fouling and increase permeate flux. Then, average rejection rates of pollutants filtratedby carbon ceramic membranes were 88~98 % for turbidity, 48~72% fort $COD_{cr}$ and 37~76% for TDS.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.7-13
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• 2014

As the interest on the air pollution is gradually rising up at home and abroad, automotive and fuel researchers have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward various main issues : whether PM emissions should be regulated for diesel and gasoline vehicles and whether gasoline and LPG powered vehicles can be further neglected from PM emission inventories. Finally, the greenhouse gas ($CO_2$, $CH_4$, $N_2O$) regulation has been discussed including automotive emission regulation. The greenhouse gas and emissions (PM) particle of automotive had many problem that cause of ambient pollution, health effects. This paper discussed the influence of LPG fuel on automotive cold startability and exhaust emissions gas. Also, this paper assessed emission characteristics due to the test temperature. These test temperature were performed by dividing the temperature of the test mode and the lowest local temperature in winter. Through this study, the correlation of cold startability, exhaust emission and greenhouse gas emission was analyzed.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.367-375
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• 2013

Kalopanax pictus has pharmacologically anti-inflammatory and analgesic effect and is known to respond to treatment of backache, knee pain and etc. In this study, we investigated the effects on gastric lesions of Kalopanax pictus both from Korea (KPK) and China (KPC) compared with their related origin, Znthoxylum ailanthoide both from Korea (ZAK) and China (ZAC), and Korean Bombax malabaricum (BMK). In preliminary screening, KPK and KPC shown effective inhibition of HCI EtOH-induced gastritis in rats. To elucidate their protective effects on gastric lesions, we assessed inhibition of H. pylori colonization, 2,2-diphenyl-1-picrylhydrazyl(DPPH) radical scavenging activities, reducing power test, and inhibition of lipid peroxidation. KPK was the most effective from antioxidant assays. KPK also shown the inhibition of indomethacin-induced gastric ulcer in rats. Gastric secretion in rats, KPK reduced the secretion of gastric juice and total acidity and raised pH. Therefore, it is possible that KPK can be developed as health functional food and natural medicine. In addition, it can contribute to the standardization with objectivity and reliability for KPK through the criteria establishment of the precise origin of medicine, the prevention of indiscriminate distribution of imitation, and the rising rate of dependence on imports of medicinal herbs, and mixing prevention of low-quality goods.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.715-721
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• 2021

Cognitive impairment and Alzheimer's disease are serious social problems associated with the rising elderly population in Korea. 1,2,3,4,6-Penta-O-galloyl-β-ᴅ-glucopyranose (PGG) is a gallotannin isolated from medicinal plants such as Rhus chinensis. This study was performed to evaluate the effect of PGG on biomarkers related to cognitive function in human neuroblastoma SK-N-SH cells. Inhibition of acetylcholinesterase (AChE) activity is considered to be one of the main therapeutic strategies. PGG inhibited AChE activity in the test tube as well as in SK-N-SH cells. In addition, PGG induced protein and mRNA expression of brain-derived neurotrophic factor (BDNF), which is a mammalian neurotrophin that plays major roles in the development, maintenance, repair, and survival of neuronal populations. As one of the underlying molecular mechanisms that induce BDNF expression, PGG induced the activation of Ca²⁺/calmodulin (CaM)-dependent protein kinase II (CaMKII)-cAMP response element binding protein (CREB) pathway. In conclusion, PGG may be an useful material for improving cognitive function.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.6
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• pp.658-665
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• 2013

In this study, we measured particulate matter(PM) which emerged as the hot issue from the International Maritime Organization(IMO) and the exhaust emission using HANBADA, the training ship of Korea Maritime University. In particular, the PM was obtained with TEM grid. PM structure was observed by electron microscopy. And exhaust gases such as NOx, $CO_2$, and CO were measured using the combustion gas analyzer(PG-250A, HORIBA). The results of this study are as follows. 1) When the ship departed from the port, the maximum difference in PM emissions were up to 30 % due to the Bunker Change. 2) Under the steady navigation, emission of PM was $1.34mg/m^3$ when Bunker-A is changing L.R.F.O(3 %). And, at the fixed L.R.F.O (3 %), emission of PM was $1.19mg/m^3$. When the main engine RPM increased up to 20 % with fixed L.R.F.O(3 %), emission of PM was $1.40mg/m^3$. When we changed to low quality oil(L.R.F.O(3 %)), CO concentration from main engine increased about 16 %. On the other hand, when the main engine RPM is rising up to 20 %, CO concentration is increased more than 152 percent. These results imply that the changes of RPM is a dominant factor in exhaust emission although fuel oil type is an important factor. 3) The diameter of PM obtained with TEM grid is about $4{\sim}10{\mu}m$ and its structure shows porous aggregate.

• Journal of Korea Soil Environment Society
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• v.3 no.3
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• pp.93-107
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• 1998

Because of its stable quantity and quality, groundwater has long been a reliable source of drinking water for domestic users. Rapid economic growth and rising standards of living have in recent years put severe demands on drinking water supplies in Korea. Groundwaters that are currently being used for natural mineral water were hydrochemically evaluated and investigated in order to maintain their quality to satisfy strict health standards. There exist 15 natural mineral water plants in the Okcheon metamorphic belt. Characteristics of groundwaters are different from those of other areas in that electrical conductivity, hardness, contents of Ca, Mg and $HCO_3$are relatively high. The content of major cations is in the order of Ca>Mg, Na>K, whereas that of major anions shows the order of $HCO_3$>$SO_4$>Cl>F. The fact that the Ca-Mg-HCO$_3$type is mostly predominant among water types reflects that dissolution of carbonates that are abundantly present in the metamorphic rocks plays an important part in groundwater chemistry. Representative correlation coefficients between chemical species show Mg-$HCO_3$(0.92), Ca-$HCO_3$(0.88), Ca-Mg(0.80), Ca-Cl(0.78), Mg-$SO_4$(0.78), Ca-$SO_4$(0.71), possibly due to the effect by dissolution of carbonates, gypsum or anhydrite. Determinative coefficients between some chemical species represent a good relationship, especially for EC-(K+Na+Ca), Ca-$HCO_3$, Ca-Mg, indiacting that they are similar in chemical behaviors. According to saturation index, most chemical species are undersaturated with respect to major minerals, except for some silica phases. Groundwater is slightly undersaturated with respect to calcite and dolomite, whereas it is still greatly undersaturated with respect to gypsum, anhydrite and fluorite, Based on the Phase equilibrium in the systems $NA_2$O-$Al_2$$O_3$-$SiO_2$-$H_2$O and $K_2$O-$Al_2$$O_3$-$SiO_2$-$H_2$O, it is clear that groundwater is in equilibrium with kaolinite, evolved from the stability area of gibbsite during water-rock interaction. It is expected that chemical evolution of groundwater continue to proceed with increasing pH by reaction of feldspars, with calcite much less reactive.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.330-336
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• 2013

Rheum tanguticum has long been used in oriental medicine as antipyretics, analgesics, anti-inflammation, aperient, hypertension medicine and medicine for skin disease. This study has investigated the effectiveness of defense for gastritis making use of Rheum tanguticum and its similar plants, Rumex cripus, Rheum officinale, Rhem palmatum and Rheum undulatum. Chysophanol, chrysophanol-8-O-glc, Desoxyrhaponticin desoxyrhaponti-genin, emodin, isorhaponticin, 2-methoxy-4-hydroxyanthraquinone-5-O-glc, physcion, pirace-tannol-3'-O-glc, resveratrol, rhaponticin and rhapontigenin are used as the components of Rheum tanguticum. In HCl ethanol-induced gastritis in rat, the most effective extract was 70 percent ethanol which is of Rheum tanguticum, showing the inhibition of 91.8 percent to the gastric lesions. 70% ethanol extract of Rhem palmatum and Rumex cripus shown inhibition of 75.6 percent and 73.2 percent, respectively. This effectiveness is considered as acid-neutralizing capacity, anti-H.pylori and anti-oxidant activity. 70% ethanol extract of Rheum tanguticum and its component, piracetannol-3'-O-glc exhibited higher free radical scavenging activity than others. These results suggest that Rheum species extracts and their active components could be utilized for the treatment of gastritis. Furthermore, these results are expected to contribute the standardization with objectivity and reliability for Rheum species, medicinal herbs. In addition, it can contribute to the prevention of indiscriminate distribution of imitation, and the rising rate of dependence on imports of medicinal herbs, and mixing prevention of low-quality goods.

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.946-953
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• 2002

Bisphenol A [2, 2 bis (4-hydoxyphenyl) propane; BPA] is a widely used endocrine disruptors and has estrogenic: activities. Although interests on biological effect of BPA are rising, evidences of its effect on immune system are lacking. We investigated that the effect of BPA on immune parameters to postulate the mechanism, and BPA interruptions between neuroendocrine and immune system. BPA was administrated to mice by p.o. (as a drinking water) dose on 0.015, 1.5 and 30 mg/ml for 4 weeks. The BPA treatment did not result in any change in body weight, spleen weight and distribution of lymphocyte subpopulation collected from spleen. BPA induced prolactin production in spleen, and exposure of SPA increased the activity of splenocyte proliferation in response to Con A (p<0.001). The production of a strong Th-1 type cytokine ($IFN-{\gamma}$) was induced while Th-2 type (IL-4) was suppressed by SPA treatment. These were consistent with RT-PCR results of transcription factor GATA-3 and IRF-1. These findings suggested that stimulation of prolactin production by estrogenic effects of SPA would affect cytokine profiles, and lead to imbalanced cellular immune response. In addition, we could speculate that prolactin and cytokine is important mediator involved in network between neuroendocrine and immune system by BPA.

• Journal of computational fluids engineering
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• v.19 no.3
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• pp.24-28
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• 2014

With ever rising concerns about saving of fossil fuel resource, there have been an increasing demand for use of energy more efficiently. The electric motor driven inverters can be a great help to improve energy efficiency. They are also used to control the motor speed to the actual need. Therefore the use of them can lead to reduce energy consumption. In particular, the medium voltage(MV) drive systems used for pumps, fans, steel rolling mills and tractions have widespread applications in the industry. They cover power ratings from 0.4MW to 40MW at the MV level of 2.3kV to 13.8kV. The majority of the installed MV drive systems however, are in the 1MW to 4MW range with voltage rating from 3.3kV to 6.6kV. But they are required to reduce size and weight like other power electronic equipments. In this paper, we studied on the 3.3kV(105A) compact rack type inverter system for improving the cooling efficiency. At first, we confirmed the tendency of temperature with computational simulation using ANSYS ICEPAK and actual experimental tests. And then we researched thermal performance improvement designs in order to reduce temperature of the transformer for the safe operation. It can reduce temperature of transformer that using pipe type flow guide in the system. As a result, we found out more efficient solution by thermal-fluid analysis.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.325-328
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• 2000

According to H.B.Lee(1993), standard Korean vowel qualities are as follows: in /i/, /e/, $/\epsilon/$, /a/, /o/, /w/, they have 4 qualities each other and in /er/ there are 3 qualities. The environments of 4 qualities are iong and stressed vowel in word initial, short and stressed vowel in word initial, unstressed vowel in word initial, unstressed vowel in word finial. The aim of this study is to seek and compare with H.B.Lee(1993). Conclusively I could not find on the whole any pattern of the same types of H.B.Lee(1993) in this study And especially in Fl vowel formant values of /er/and /w/, I never found any pattern of the same types of H.B.Lee(1993). Also F2 vowel formant values of $/\varepsilon/$ and /w/ do not have any kind of pattern of the same types of H.B.Lee(1993), between them, the patternize of F2 vowel formant values in /w / is especially difficult. It is the same story of Jaekang Lee(1998). But in some case, the patternize could be done. among the whole vowels, analysis environment b has the wide width on the change of the formant value. As the another result of the analysis It is to possible to make the pattern of the old male group. The old male group on the whole is analyzed to have the most low formant values and the old women group is analyzed to have the most high formants values, but in the most high formant valus there are young women group. And the formant values's rising in 2 cases of the formant value of /er/ is analyzed to have the same pattern of H.B.Lee(1993).