• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.106.1-106.1
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• 2013

When strong static magnetic field is applied to the TMP, it is expected that the presence of the magnetic field might retard the velocity of the blades which results in the change of the pumping speed of the TMP. However, such effect of the magnetic field on the TMP has not been well characterized. Thus, under the strong magnetic field, monitoring pumping speed as well as generated heat, pressure, and vibration of the TMP may be an important issue to understand the magnetic field tolerance of the TMP and the development of magnetic shielding technique for the key components of the pump. For this purpose, magnetic field generation system to the vertical direction by a circular current source was firstly designed and suggested [K. Baik et al., 44th Annual Conf. KVS, 22(1), 153, (2012)]. In the current study, another magnetic field generation systems are presented to apply the magnetic field to the horizontal and radial directions by the rectangular current sources and the permanent magnets respectively. Such systems were made to generate at least 50 Gauss of magnetic field along the vertical direction and at least 25 Gauss of magnetic field along the horizontal or radial direction. Current study introduces the evaluation system of the magnetic field along the vertical, horizontal, and radial directions and presents the measured experimental results of the magnetic field when such systems are combined with the equipment where TMP will be installed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.6
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• pp.381-387
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• 2008

The presence of non-condensable gases as an additional thermal resistance inside a refrigerating circuit has been found for a general refrigerator, The effect of non-condensable gases was varied by controlling the injection amount of dry air into the refrigerating circuit to increase a thermal resistance. Energy consumption tests for the refrigerator were conducted under the various amounts of non-condensable gases. The tested refrigerating circuit was the household refrigerator. As the molar fraction of non-condensable gases was increased from 0% to 1.46%, the amount of energy consumption was found to increase up to 25%. The increase of the amount of non-condensable gases in refrigerating circuit was found to result in increasing the condensation temperature at the condenser and decreasing the evaporation temperature at the evaporator, which were presumably caused by the low specific heat and increased partial pressure of non-condensable gas.

• YAKHAK HOEJI
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• v.51 no.4
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• pp.264-269
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• 2007

Alzheimer’s disease (AD) is characterized pathologically by the presence of intracellular neurofibrillary tangles and deposition of ${\beta}-amyloid $ (A ${\beta}$) peptides, which are generated by processing of amyloid precursor protein (APP). It is urgent to develop effective therapies for the treatment of AD, since our society rapidly accelerate aging. A${\beta}$ peptides have been believed to be neurotoxic and now are also considered to have effects on the mechanism of memory formation. In this study, effects of radicicol on the metabolism of APP were analyzed. Radicicol inhibited the secretion of A${\beta}$ from the Neuro2a cell line (APPswe cell) expressing APPswe. Beta-site APP cleaving enzyme (BACE) fluorescence resonance energy transfer (FRET) assay revealed that it inhibited BACE activity in a dose dependently manner. Immunoblotting study showed that it inhibited intracellular heat shock protein (HSP)90 and it increased the secretion of HSP90 from the APPswe cells. We suggest that radicicol inhibits APP metabolism and Ap generation by the means of HSP90 inhibitory mechanism and partially BACE inhibitory mechanism. This is the first report that radicicol inhibits the secretion of A${\beta}$ peptides from neuroblastoma cells.

• Journal of fish pathology
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• v.5 no.1
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• pp.9-18
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• 1992

In order to know the defense mechanism of fish, bactericidal activity was examined into the sera of carp Cyprinus carpio, tilapia Oreochromis niloticus and flounder Paralichthys olivaseus. Each examined normal serum of fishes showed the bactericidal activity against avirulent Escherichia coli but it wasn't appeared against virulent Edwardsiella tarda. When the normal serum of each fish was treated with zymosan, it lost the bactericidal activity completely. After addition of EGTA into the normal serum of each fish, the sera of tilapia and flounder still exhibited the bactericidal activity but the serum of carp lost it. In the presence of specific antibody and complement, bactericidal activity of each antiserum was exhibited high level with in one hour incubation. On the other hand, heat inactivated antiserum showed bacteriostatic reaction. From the above results, although the activity of alternative or classical pathway of each fish complement is different, it is an important function in fish defense mechanism.

• Korean Journal of Pharmacognosy
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• v.46 no.1
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• pp.17-22
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• 2015

Previous phytochemical studies of Vigna angularis (Ohwi) Ohwi & Ohashi (Leguminosae) have shown the presence of saponins and flavonoids. From the seed of V. angularis, genistein-7-O-${\beta}$-D-glucopyranoside (genistin) was isolated. Lifespan-extending effect of genistin was elucidated using Caenorhabditis elegans model system. Genistin showed potent lifespan extension of worms under normal culture condition. This compound also exhibited the protective effects against thermal and oxidative stress conditions. In the case of heat stress, genistin-treated worms exhibited enhanced survival rate, compared to control worms. In addition, genistin-fed worms lived longer than control worms under oxidative stress induced by paraquat. To verify the possible mechanism of genistin-mediated increased lifespan and stress resistance of worms, we investigated whether genistin might alter superoxide dismutase (SOD), catalase activities and intracellular ROS levels. Our results showed that genistin was able to elevate SOD and catalase activities of worms and reduce intracellular ROS accumulation in a dose-dependent manner.

• Journal of Microbiology
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• v.42 no.2
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• pp.117-125
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• 2004

Propionibacterium acnes (P. acnes) plays an important role in the disease pathogenesis of acne vulgaris, a disorder of pilosebaceous follicles, seen primarily in the adolescent age group. In the present study, the presence of antibodies against P. acnes (MTCC1951) were detected in acne patient (n=50) and disease free controls (n=25) using dot-ELISA and Western blot assay. The ability of P. acnes to induce pro-inflammatory cytokines by human peripheral blood mononuclear cells (PBMCs), obtained from acne patients and healthy subjects, were also analysed. The patients (n=26) who were culture positive for skin swab culture, were found to have a more advanced disease and higher antibody titres (1:4000 to >1:16000) compared to the P. acnes negative patients (n=24) and normal controls (n=25). An analysis of patients' sera by western blot assay recognized a number of antigenic components of P. acnes, rang-ing from 29 to 205 kDa. The major reactive component was an approximately 96 kDa polypeptide, which was recognised in 92％ (24 of 26) of the patients sera. Further, the P. acnes culture supernatant, crude cell lysate and heat killed P. acnes whole cells, obtained from 72-h incubation culture, were observed to be able to induce significant amounts of IL-8 and tumor necrosis factor alpha (TNF-${\alpha}$) by the PBMCs in both the healthy subjects and patients, as analysed by cytokine-ELISA. The levels of cytokines were significantly higher in the patients than the healthy subjects. A major 96 kDa polypep-tide reactant was eluted from the gel and was found to cause dose dependent stimulation of the pro-ductions of IL-8 and TNF-${\alpha}$. Thus, the above results suggest that both humoral and pro-inflammatory responses play major roles in the pathogenesis of acne.

• Journal of Welding and Joining
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• v.31 no.6
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• pp.50-57
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• 2013

Characterization of microstructures and cryogenic mechanical properties of electro beam (EB) welds between cast and forged Inconel 718 superalloys has been investigated. Optimal EBW condition was found in the beam current range of 36~39 mA with the constant travel speed of 12 mm/s and arc voltage of 120 kV for 10 mm-thick specimens. Electron beam current lower than 25 mA caused to occur the liquation microfissuring in cast-side heat affected zone (HAZ) of EB welds. The HAZ liquation microfissure was found on the liquated grain boundaries with resolidified ${\gamma}/Laves$ and ${\gamma}/NbC$ eutectic constituents. EBW produced welds showing a fine dendritic structure with relatively discrete Laves phase due to fast cooling rate. After post weld aging treatment, blocky Laves phase and formation of ${\gamma}^{\prime}+{\gamma}^{{\prime}{\prime}}$ strengtheners were observed. Presence of primary strengthener and coarse Laves particles in PWHT weld may cause to reduce micro-plastic zone ahead of a crack, leading to a significant decrease in Charpy impact toughness at $-196^{\circ}C$. Fracture initiation and propagation induced by Charpy impact testing were discussed in terms of the dislocation structures ahead of crack arisen from the fractured Laves phase.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.112-112
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• 2002

Under normal conditions, women produce a single dominant follicle that participates in a single ovuation each menstrual cycle. But Polycystic ovary syndrome(PCOS) conditions, folliculogenesis does not proceed normally. This condition leads to the accumlation of large numbers of small graffian follicles in which the theca interstitial cells (TIC) produce abnormally large amounts of androgen. PCOS is probably the most common endocrine disorder, affecting women of reprodutive age with 5-10% prevalence estimate. Chronic anovulation, hyperandrogenism, hirsutism, obesity, infertility and polycystic ovaries are clinical hallmarks of women with PCOS. Its etiology remains unknown. To investigate the gene expression pattern of ovary in PCO-induced rat, we used cDNA expression analysis. Total RNA was extracted from the ovary of PCO-induced rat and reverse-transcribed in the presence of［$\alpha$$^{32}$P］-dATP Which were hybridized to Atlas$^{TM}$ Rat Toxicology 1.2 array (Clontech) representing approximately 1176 rat genes. We compared gene expression between ovary of pco-induced immature female rats and control. Differential gene expression profiles were revealed (LIFR-alpha, ADRA1A, Heat shock 90-kDa protein A, PDGFRA). Reverse transcription-polymerase chain reaction(RT-PCR) was used to validate the relative expression pattern obtained by the cDNA array. The precise relationship between the altered expression of genes and PCO is a matter of further investigation. This study was supported by Korea Science and Engineering Foundation(KOSEF)

• Advances in materials Research
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• v.13 no.3
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• pp.161-171
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• 2024

This study aimed to investigate the effect of physicochemical properties and mix ratios of iron ore (oxide feed): coke (reductant) on the carbothermic reductions of iron ore. Coke size was fixed at ≤63 ㎛ while iron ore size varied between 150-63 ㎛ and ≤63 ㎛ respectively. Mix ratios were changed from 100:0 (reference) to 80:20 and 60:40 while the temperature, heating rate and soaking duration in muffle furnace were fixed at 1100 ℃, 10 ℃/min and 1 hour. Particle size analyzer, XRF, CHNS and XRD analyses were used for determination of raw feed characteristics. The occurrence of phase transformations from various forms of iron oxides to iron during the carbothermal reductions were identified through XRD profiles and supported with weight loss (%). XRF analysis proved that iron ore is of high grade with 93.4% of Fe₂O₃ content. Other oxides present in minor amounts are 2% Al₂O₃ and 1.8% SiO₂ with negligible amounts of other compounds such as MnO, K₂O and CuO. Composite pellet with finer size iron particles (≤63 ㎛) and higher carbon content of 60:40 exhibited 45.13% weight lost compared to 32.30% and 3.88% respectively for 80:20 and 100:0 ratios. It is evident that reduction reactions can only occur with the presence of coke, the carbon supply. The small weight loss of 3.88% at 100:0 ratio occurs due to the removal of moisture and volatiles and oxidations of iron ore. Higher carbon supply at 60:40 leads into better heat and mass transfer and diffusivity during carbothermic reductions. Overall, finer particle size and higher carbon supply improves reactivity and gas-solid interactions resulting in increased reductions and phase transformations.

• Membrane and Water Treatment
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• v.15 no.3
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• pp.107-115
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• 2024

This study proposes the recycling of MVS as a value-added product for the removal of phosphate from aqueous solutions. By comparing the phosphate adsorption capacity of each calcined adsorbent at each temperature of MVS, it was determined that the optimal heat treatment temperature of MVS to improve the phosphate adsorption capacity was 800 ℃. MVS-800 suggests an adsorption mechanism through calcium phosphate precipitation. Subsequent kinetic studies with MVS-800 showed that the PFO model was more appropriate than the PSO model. In the equilibrium adsorption experiment, through the analysis of Langmuir and Freundlich models, Langmuir can provide a more appropriate explanation for the phosphate adsorption of MVS-800. This means that the adsorption of phosphate by MVS-800 is uniform over all surfaces and the adsorption consists of a single layer. Thermodynamic analysis of thermally activated MVS-800 shows that phosphate adsorption is an endothermic and involuntary reaction. MVS-800 has the highest phosphate adsorption capacity under low pH conditions. The presence of anions in phosphate adsorption reduces the phosphate adsorption capacity of MVS-800 in the order of CO 3 2-, SO 4 2-, NO 3- and Cl-. Based on experimental data to date, MVS-800 is an environmentally friendly adsorbent for recycling waste resources and is considered to be an adsorbent with high adsorption capacity for removing phosphates from aqueous solutions. This paper combines the advantages of gray predictor and AI fuzzy. The gray predictor can be used to predict whether the bear point exceeds the allowable deviation range, and then perform appropriate control corrections to accelerate the bear point to return to the boundary layer and achieve.