• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3370-3375
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• 2014

MILD combustion is a highly favored technology for solving the trade-off relation between high thermal efficiency and low pollutant emissions. The system has low NOx concentration in high temperature combustion by recirculating the combustion gas, as well as improving the thermal efficiency by making the internal temperature in a combustion furnace uniform. This study describes the combustion characteristics of a conical MILD combustor in a laboratory-scale furnace by adjusting the equivalence ratio with the fuel gas flow rate while maintaining a constant air flow rate of the furnace. The MILD regime in the furnace is well characterized and the in-furnace temperature and emissions were predicted, respectively, for the range of equivalence of 0.69 - 0.83. For the range of equivalence ratios, this study confirmed the existence of a stable flame region that has an approximately $300^{\circ}C$ temperature difference between the maximum flame temperature region and main reaction region.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.1
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• pp.1-9
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• 2010

In this study, the selective catalytic reduction of $NO_x$ with ammonia was carried out in a filter bag support reactor. The experiments were performed by powder type $MnO_x$ and $V_2O_5$/$TiO_2$ catalyst at low temperature between 130 and $250^{\circ}C$. Also, the effect of $SO_2$ and $H_2O$ on the NO conversion was investigated under our test conditions. The powder type catalysts were analyzed by X-ray photoelectron spectrum (XPS), X-ray diffraction(XRD), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). It was observed that NO removal efficiency of the powder type $V_2O_5$/$TiO_2$ catalyst was 85% at low temperature($200^{\circ}C$) under presence of oxygen and that of $MnO_x$ was 50% at the same condition. The powder type $V_2O_5$/$TiO_2$ catalyst, in conclusion, was found to be available for SCR reaction in a filter bag support system.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1354-1367
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• 2014

In the present work, we describe a simple, cheap, and unexplored method for "green" synthesis of silver nanoparticles using cell extracts of the cyanobacterium Anabaena doliolum. An attempt was also made to test the antimicrobial and antitumor activities of the synthesized nanoparticles. Analytical techniques, namely UV-vis spectroscopy, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and TEM-selected area electron diffraction, were used to elucidate the formation and characterization of silver-cyanobacterial nanoparticles (Ag-CNPs). Results showed that the original color of the cell extract changed from reddish blue to dark brown after addition of silver nitrate solution (1 mM) within 1 h, suggesting the synthesis of Ag-CNPs. That the formation Ag-CNPs indeed occurred was also evident from the spectroscopic analysis of the reaction mixture, wherein a prominent peak at 420 nm was noted. TEM images revealed well-dispersed, spherical Ag-CNPs with a particle size in the range of 10-50 nm. The X-ray diffraction spectrum suggested a crystalline nature of the Ag-CNPs. FTIR analysis indicated the utilization of a hydroxyl (-OH) group in the formation of Ag-CNPs. Ag-CNPs exhibited strong antibacterial activity against three multidrug-resistant bacteria. Additionally, Ag-CNPs strongly affected the survival of Dalton's lymphoma and human carcinoma colo205 cells at a very low concentration. The Ag-CNPs-induced loss of survival of both cell types may be due to the induction of reactive oxygen species generation and DNA fragmentation, resulting in apoptosis. Properties exhibited by the Ag-CNP suggest that it may be used as a potential antibacterial and antitumor agent.

• Environmental Engineering Research
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• v.16 no.4
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• pp.187-203
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• 2011

Chlorophenols (CPs) are widely used industrial chemicals that have been identified as being toxic to both humans and the environment. Zero valent iron (ZVI) and iron based bimetallic systems have the potential to efficiently dechlorinate CPs. This paper reviews the research conducted in this area over the past decade, with emphasis on the processes and mechanisms for the removal of CPs, as well as the characterization and role of the iron oxides formed on the ZVI surface. The removal of dissolved CPs in iron-water systems occurs via dechlorination, sorption and co-precipitation. Although ZVI has been commonly used for the dechlorination of CPs, its long term reactivity is limited due to surface passivation over time. However, iron based bimetallic systems are an effective alternative for overcoming this limitation. Bimetallic systems prepared by physically mixing ZVI and the catalyst or through reductive deposition of a catalyst onto ZVI have been shown to display superior performance over unmodified ZVI. Nonetheless, the efficiency and rate of hydrodechlorination of CPs by bimetals depend on the type of metal combinations used, properties of the metals and characteristics of the target CP. The presence and formation of various iron oxides can affect the reactivities of ZVI and bimetals. Oxides, such as green rust and magnetite, facilitate the dechlorination of CPs by ZVI and bimetals, while oxide films, such as hematite, maghemite, lepidocrocite and goethite, passivate the iron surface and hinder the dechlorination reaction. Key environmental parameters, such as solution pH, presence of dissolved oxygen and dissolved co-contaminants, exert significant impacts on the rate and extent of CP dechlorination by ZVI and bimetals.

• 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.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.300-304
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• 1999

To tap the feasibility of exploiting the 2$^{nd}$ phases as flux-pinning centers in the (Bi,Pb)$_2Sr_2Ca_2CuO_{10}$ superconductor, the size and the distribution of the precipitates have been controlled by changing reaction temperature and time, oxygen partial pressure Po$_2$ and annealing condition. Various annealing heat treatments were also conducted on the as-received 61 filament Bi-2223 tapes with Bi$_{1.8}Pb_{0.4}Sr_2Ca_{2.2}Cu_3O_8$ starting composition and annealed specimen were analyzed with XRD, SEM, EDS and TEM.. The grain size of (Ca,Sr)$_2$(BiPb)O$_4$ or Bi$_{0.5}Pb_3Sr_2Ca_2CuO_{\delta}$ was controllable by optimizing the heat treatment condition and critical current density (J$_c$) showed dependence on the size of the 2$^{nd}$ phases.

• Polymer(Korea)
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• v.25 no.6
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• pp.866-875
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• 2001

In this work, thermal decomposition mechanism based on kinetic parameters and thermal stability of carbon fiber-reinforced carbon matrix composites (C/C composites), have been studied under high temperature oxidative conditions with addition of tetra-ethylorthosilicate (TEOS) as an oxidation inhibitor. Thermogravimetric analysis (TGA) was executed to evaluate the thermal decomposition mechanism and thermal stability of C/C composites in the temperature range of 30 ～ $850^{\circ}C$. As a result, the kinetic parameters of the composites impregnated with TEOS, i.e., activation energy for thermal decomposition ($E_d$), order of reaction (n) , and pre-exponential factor (A) were evaluated as 136 kJ/mol, 0, and 2.3$\times$$10^9s^{-1}$, respectively. Especially, the IPDT and $E_d$ of C/C composites impregnated with TEOS were improved largely compared with the composites impregnated without TEOS, due to the formation of $SiO_2$ on composite surfaces, resulting in interrupting the oxygen attack to carbon active site in the composites.

• Polymer(Korea)
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• v.38 no.4
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• pp.457-463
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• 2014

In this study, the changes in the chemical structure and the physical property of fluoropolymer films (PTFE, FEP, PFA, PVDF, and ETFE) induced by $Co^{60}$ gamma ray in air, $N_2$, and vacuum environments were investigated. FTIR spectra of the irradiated fluoropolymers indicate that the oxidation proceeded by the reaction of radicals generated by irradiation with oxygen in air. The changes in the heat of fusion and the degree of crystallinity of the irradiated fluoropolymers were investigated using DSC and the results indicate that the scission and crosslinking reactions of the irradiated fluoropolymers were largely influenced by the chemical structure. It was also found that the mechanical property of the irradiated fluoropolymer films under an air atmosphere was significantly decreased.

• Journal of Veterinary Clinics
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• v.34 no.5
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• pp.356-358
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• 2017

A dog (neutered male Schnauzer, 11 years old, 8 kg) presented with recurrence of immune-mediated hemolytic anemia. Rapid whole blood transfusion was initiated, and then sudden tachycardia and dyspnea were observed. Invasive arterial blood pressure, arterial blood gas analysis, and thoracic radiograph indicated transfusion-associated circulatory overload (TACO). Persistent high blood pressure of 160-205 mmHg was observed; the thoracic radiograph revealed interstitial infiltration and a fissure line, which suggested pulmonary edema and pleural effusion. Despite furosemide administration and nasal oxygen supplementation, hypertension and respiratory distress were not completely controlled. Finally, cardiac arrest occurred and the patient expired due to TACO 24 hours after the transfusion.

• Journal of Chest Surgery
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• v.45 no.1
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• pp.1-10
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• 2012

Background: ${\alpha}$-Lipoic acid (${\alpha}$-LA) has been studied as an anticancer agent as well as a therapeutic agent for diabetes and obesity. We performed this study to evaluate the anticancer effects and mechanisms of ${\alpha}$-LA in a lung cancer cell line, A549. Materials and Methods: ${\alpha}$-LA-induced apoptosis of A549 cells was detected by fluorescence-activated cell sorting analysis and a DNA fragmentation assay. Expression of apoptosis-related genes was analyzed by western blot and reverse transcription.polymerase chain reaction analyses. Results: ${\alpha}$-LA induced apoptosis and DNA fragmentation in A549 cells in a dose- and time-dependent manner. ${\alpha}$-LA increased caspase activity and the degradation of poly (ADP-ribose) polymerase. It induced expression of endoplasmic reticulum (ER) stress-related genes, such as glucose-regulated protein 78, C/EBP-homologous protein, and the short form of X-box binding protein-1, and decreased expression of the anti-apoptotic protein, X-linked inhibitor of apoptosis protein. Reactive oxygen species (ROS) production was induced by ${\alpha}$-LA, and the antioxidant N-acetyl-L-cysteine decreased the ${\alpha}$-LA-induced increase in expression of apoptosis and ER stress-related proteins. Conclusion: ${\alpha}$-LA induced ER stress-mediated apoptosis in A549 cells via ROS. ${\alpha}$-LA may therefore be clinically useful for treating lung cancer.