• Journal of the Korean Electrochemical Society
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• v.11 no.2
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• pp.115-119
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• 2008

Single particle of nickel hydroxide and the surface-treated one with cobalt element were performed to review the effect of LiOH additive in alkaline electrolyte for Ni-MH batteries using microelectrode test system. As a result of cyclic voltammetry, the electrochemical behaviors such as the oxidation/reduction and oxygen evolution reaction are clearly observed for a single particle of nickel hydroxide, respectively. Furthermore, the reduction current peak of nickel hydroxide added with LiOH in electrolyte was very low and broad compared with the normal nickel hydroxide without an additive LiOH, which had a bad effect to the crystallization structure of nickel hydroxide. However, it was found that capacity and cycle properties of the nickel hydroxide treated with cobalt greatly increased by the addition of LiOH.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.6
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• pp.602-610
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• 2008

Purpose Acrylamide is present in significant quantities in a wide range of commonly consumed human foods. Carcinogenic risk of acrylamide through the consumption of food is a great public concern and in controversy, but it is not properly addressed due to the lack of evidence in humans. While a plenty of data is available on the carcinogenicity in animal models, the studies in humans are limited. Thus, the present study attempted to examine the carcinogenic potentials of acrylamide on the human epithelial cell, which is the target cell origin of the most cancers. Material and method & Result 1. Acrylamide was not cytotoxic up to $100{\mu}M$ as measured by MTT and LDH assays, indicating a relatively low toxicity of this substance in human epithelial cells. 2. The parameters of neoplastic cellular transformation such as cell saturation density, soft-agar colony formation and cell aggregation were analyzed to examine the carcinogenic potential of acrylamide. 3. The neoplastic transformation was further increased with the co-treatment of TPA 4. Antioxidants blocked the generation of Reactive Oxygen Species(ROS) and the GSH depleting agent dramatically increased the ROS production. 5. mRNA levels of fibronectin following acrylamide exposure was increased in a dose-dependent manner, indicating a possible biomarker of acrylamide-induced cellular transformation. Conclusion The present study will provide a valuable basis to compare the interspecies differences in response to carcinogenic potentials of acrylamide. The data on the interspecies differences are essential element in human risk assessment. Thus, our results obtained from the human epithelial cells will contribute to improving the risk assessment of human neoplasm including oral cancer.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.36-43
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• 2016

With transient flooding followed by poor or slow drainage plant roots may become reduction conditions because the root zone was fully filled with water. This study was examined the effects of calcium treatment in the early growth stage on biochemical changes in leaves and roots of melon (Cucumis melo L.) seedlings kept under flooding condition for 72 h. The activities of lactate dehydrogenase more gradually enhanced in the roots than those of leaves of melon seedlings treated with calcium. The activities of alcohol dehydrogenase associated with alcohol fermentation under low oxygen conditions continuously increased in the leaves and roots of seedlings untreated with calcium under flooding at least 72 h but those was constant within at least 12 h in treated with calcium. These results showed that calcium supplying in the early growth stage mitigated alcohol fermentation of melon seedlings kept under flooding condition for 72 h. Activities of nitrate reductase and acid phosphatase in the leaves and roots of seedlings in treated with calcium somewhat higher than those of non-treated with calcium. The activities of sucrose phosphate synthase and fructose-1,6-bisphosphatase of leaves of seedlings in treated with calcium more higher than those of non-treated with calcium. These results indicated that calcium nutrition mitigate the reduction of activities of some enzymes of melon seedling kept under flooding condition for 72 h.

• Korean Journal of Materials Research
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• v.19 no.10
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• pp.517-521
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• 2009

Si-C composite with hollow spherical structure was synthesized using ultrasonic treatment of organosilica powder formed by hydrolysis of phenyltrimethoxysilane. The prepared powder was pyrolyzed at various temperatures ranging from 900 to 1300 $^{\circ}C$ under nitrogen atmosphere to obtain optimum conditions for Li-ion battery anode materials with high capacity and cyclability. The XRD and elemental analysis results show that the pyrolyzed Si/C composite at 1100 $^{\circ}C$ has low oxygen and nitrogen levels, which is desirable for increasing the electrochemical capacity and reducing the irreversible capacity of the first discharge. The solid Si-C composite electrode shows a first charge capacity of $\sim$500 mAhg$^{-1}$ and a capacity fade within 30 cycles of 0.93% per cycle. On the other hand, the electrochemical performance of the hollow Si-C composite electrode exhibits a reversible charge capacity of $\sim$540 mAhg$^{-1}$ with an excellent capacity retention of capacity loss 0.43% per cycle up to 30 cycles. The improved electrochemical properties are attributed to facile diffusion of Li ions into the hollow shell with nanoscale thickness. In addition, the empty core space provides a buffer zone to relieve the mechanical stresses incurred during Li insertion.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.207-217
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• 1992

In this study, isolated and cultured nitrogen fixed microbes were seeded in the three-phase fluidized bed in which gas, solid and liquid were contacted directly. Input velocity was varied from 8.12 cm/hr to 16.32 cm/hr. And upflow gas pressure was fixed to 80 psi. Return ratios were from 0.2 to 0.6 with the each experimental condition. According to these condition, movement of media, growth of biofilm and removal efficiency were measured. As the results, in case of briquette ash, biofilm was developed to $170{\mu}m$ when velocity was 8.12 cm/hr and return ratio was 0.6. In this condition, COD removal efficiency was 97% and $NH_4$-N removal efficiency was 83%. At the same condition, biofilm thickness of glass bead was $17.59{\mu}m$ and its COD and $NH_4$-N removal efficiency was 83% and 72%. Nitrogen fixed microbes have following characters: it formed dark-brownish sludge, excellent adhesive force, easy solid-liquid separation and low oxygen uptake ratio, but sensitive to DO concentration. Not only it endured shock loading, but required short time to steady state.

• Journal of Soil and Groundwater Environment
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• v.21 no.6
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• pp.192-203
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• 2016

A field investigation was conducted on an aquifer contaminated with trichloroethylene (TCE) for application of in situ reactive zone treatment using nanosized zero-valent iron (NZVI). The aquifer was an unconfined aquifer with a mean hydraulic conductivity of $5.14{\times}10^{-4}cm/sec$, which would be favorable for NZVI injection. Seasonal monitoring of TCE concentration revealed a presence of non-aqueous phase liquid form of TCE near IW (injection well). The hydrochemical data characterized the site groundwater to be a $Ca-HCO_3$ type. The average value of Langelier Saturation Index of the groundwater was -1.33, which implied that the site was favorable for corrosion of NZVI. Dissolved oxygen (DO) concentration varied between 2.5~11.5 mg/L, which indicated that DO would greatly compete with TCE as an electron acceptor. The hydrogeological and hydrochemical characterization reveals that the time around November would be appropriate for NZVI injection when water level and temperature are relatively high and DO concentration is low.

• Journal of Chest Surgery
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• v.17 no.3
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• pp.409-417
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• 1984

In the early days of open heart surgery, acute respiratory failure following extracorporeal circulation was a significant deterrent to an uncomplicated recovery. Although a marked improvement in prevention and treatment of postoperative respiratory failure has been achieved, the problem has not been completely eliminated and continues to be a causative factor in morbidity and mortality Fates following open heart surgery. We have attempted to evaluate postoperative respiratory failure in patients undergoing cardiac operation with the aid of extracorporeal circulation. Our series comprised 92 patients who underwent elective open heart surgery at the Department of Thoracic and Cariodvascular Surgery, School of Medicine, Kyungpook National University, from January, 1980 to December, 1982. In our study, the overall incidence of acute respiratory failure following open heart surgery was 18.8 percent. The duration of extracorporeal circulation in a series of 18 patients who developed postoperative respiratory failure [Group B] was longer in the mean value [120.3 minutes] than the uncomplicated 74 patients [Group A] [85.8 minutes]. The duration of artificial ventilation after open heart surgery in Group A averaged 13.4 hours as contrasted with 76.5 hours in Group B. In Group B, the inspired oxygen concentration [FiO2] in artificial ventilation was continued in the higher level than Group A until 18 hours after operation. Upon pulmonary function test performed pre-and postoperatively, residual volume[RV], RV/TLC and FEV 1.0/FVC were remained essentially unchanged following extracorporeal circulation, whereas forced vital capacity [FVC], FEV 1.0 and FEF 25-75% were significantly decreased in the early postoperative days. The incidence of acute respiratory failure was significantly higher in a series of patients who developed postoperative complications, such as re- exploration due to massive bleeding, low cardiac output, acute renal failure and arrhythmias. A total of 9 patients died, giving an overall mortality was 33.3 percent whereas the mortality was only 1.1 percent for patients without respiratory failure.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.6
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• pp.95-99
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• 2013

Furnace is currently the most important doping process using POCl3 in solar cell. However furnace need an expensive equipment cost and it has to purge a poisonous gas. Moreover, furnace typically difficult appling for selective emitters. In this study, we developed a new atmospheric pressure plasma source, in this procedure, we research the atmospheric pressure plasma doping that dopant is phosphoric acid($H_3PO_4$). Metal tube injected Ar gas was inputted 5 kV of a low frequency(scores of kHz) induced inverter, so plasma discharged at metal tube. We used the P type silicon wafer of solar cell. We regulated phosphoric acid($H_3PO_4$) concentration on 10% and plasma treatment time is 90 s, 150 s, we experiment that plasma current is 70 mA. We check the doping depth that 287 nm at 90 s and 621 nm at 150 s. We analysis and measurement the doping profile by using SIMS(Secondary Ion Mass Spectroscopy). We calculate and grasp the sheet resistance using conventional sheet resistance formula, so there are 240 Ohm/sq at 90 s and 212 Ohm/sq at 150 s. We analysis oxygen and nitrogen profile of concentration compared with furnace to check the doped defect of atmosphere.

• Journal of Pharmaceutical Investigation
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• v.37 no.4
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• pp.243-247
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• 2007

Retinoids have many important and diverse functions and particularly, have been widely used as anti-aging agent and for the treatment of acne and psoriasis in cosmetics. However, retinoids have low stability against the air, light, water, oxygen and heat, thus, to stabilize the retinoids in formulations is very critical procedure. In this study, cubic liquid crystalline phase of monoolein was applied to stabilize the retinylpalmitate (RP) and to enhance the transdermal permeation. Cubic liquid crystalline phase significantly enhanced the stability of RP. After 15 days, the content of RP in the cubic formulation was 94.7% while the content of RP in ethanol solution was below 0.5% at room temperature. Although BHT containing crystalline phase showed the slightly increased stability of RP, there were no significant differences in RP stability between with or without antioxidants (ascorbic acid, ${\alpha}$-tocopherol, BHT, BHA) at $40^{\circ}C$. The skin retention of RP in crystalline formulations was approximately $5.3{\sim}6.4$ times greater than that of o/w cream formulation. Incorporation of RP into cubic liquid crystalline phase of monoolein effectively stabilized the RP and worked as excellent topical vehicle for RP. Liquid crystalline phase is considered to be suitable formulation for RP for topical delivery system as a stabilizer and permeation enhancing agent.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.913-916
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• 2001

From 1994 the cooperation between NEU of China and MJU of South Korea for study of ReBaCuO (Re=Rare earth elements) superconductors has been carried out. The progress has been got in following projects. Critical current density ($J_c$) of YBaCuO superconductor prepared by Melting Textured Growth (MTG) was improved. In the preparation of textured YBaCuO, 20 wt.% of YBaCuO 211 phase was added, which would be climactic for the microcracks in the textured YBaCuO. The effects of the 211 phase and Ag content on the superconductivity were studied and discussed in detail. The improved $J_c$ value was reached to 8$\times$10^4 A/cm^2 (77K,0T). Single phase $YbBa_{2}Cu_{3}O_{x}$ superconductor was sintered by the traditional powder metallurgical method, and its reaction process was studied. In recent years, NdBaCuO superconductor is being performed. The behavior of $Nd_{4}Ba_{2}Cu_{2}O_{10}$(Nd422 phase) and the solid solubility, x in the superconductor $Nd_{1+x}Ba_{2-x}Cu_{3}O_{y}$ by the heat treatment in the low oxygen partial pressure (1%) or Ar at $950{\circ}C$ were investigated. The zone-melting process was used to make oriented NdBaCuO superconductor in order to increase the critical current density.