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Search Results: 1 - 10 of 25936 matches for " Seong-Ryong Lee "
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A Parallel Processing Uninterruptible Power Supply for Sudden Voltage Fluctuation for Power Management  [PDF]
Sung-Hun Ko, Seong-Ryong Lee
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.51B003

This paper deals with a parallel processing uninterruptible power supply (UPS) for sudden voltage fluctuation in power management to integrate power quality improvement, load voltage stabilization and UPS. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, only one voltage-controlled voltage source inverter (VCVSI) is used. The VCVSI is connected in series on the DC battery side and in parallel on the AC grid side with a decoupling inductor. The system provides sinusoidal voltage at the fundamental value of 220V/60Hz for the load during abnormal utility power conditions or grid failure. Also, the system can be operated to mitigate the harmonic current and voltage demand from nonlinear loads and provide voltage stabilization for loads when sudden voltage fluctuation occur, such as sag and swell. The experimental results confirm the system protects against outages caused by abnormal utility power conditions and sudden voltage fluctuations and change.

Effect of L-Deprenyl on the Putrescine Level and Neuronal Damage after Transient Global Cerebral Ischemia in Gerbils  [PDF]
Hyung Lee, Yeun-Kyung Chu, Joon-Ho Shon, Kyung-Hee Chun, Jee-In Kim, Seong-Ryong Lee
International Journal of Organic Chemistry (IJOC) , 2017, DOI: 10.4236/ijoc.2017.72014
Abstract: L-Deprenyl is selective and irreversible monoamine oxidase B inhibitor, known to have neuroprotective properties. Putrescine, one of polyamine, is thought to be important in the neuronal cell damage associated with various type of excitatory neurotoxicity. We examined the effects of L-deprenyl on the changes in putrescine level and neuronal damage after transient global ischemia in ger-bils. Male Mongolian gerbils weighing 65 - 75 g were used in the experiment. Global ischemia was induced by occlusion of common carotid arteries for 3 min to observe neuronal injury in hippocampal pyramidal cells. L-Deprenyl group was given 10 mg/kg of L-deprenyl intraperitoneally immediately after, 3 h and 6 h after global ischemia. Treated animals were processed in parallel with ischemic animals receiving saline as a vehicle and with sham- operated controls. Hippocampal putrescine level was increased by global ischemia and inhibited by L-deprenyl treatment. In histological findings, counts of viable neurons were made in the pyramidal cell layer of the hippocampal CA1 area 3 days after ischemic insult. The number of viable neurons in the pyramidal cell layer of CA1 area was significantly increased in animals treated with L-deprenyl compared to vehicle-treated ischemic animals (p < 0.05). In terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick endlabeling (TUNEL) assay, semiquantitative analysis of dark-brown neuronal cells was made in the hippocampal CA1 area. There was also a significant difference in the degree of TUNEL staining in the hippocampal CA1 area between vehi-cle-treated and L-deprenyl-treated animals (p < 0.05). These data show L-deprenyl is effective as a prophylactic treatment for neuronal injury when it is administrated before ischemia but a further study need to know the effects of administration of L-deprenyl after ischemia and at given times after reper-fusion.
A Study on Water Repellent Effectiveness of Natural Oil-Applied Soil as a Building Material  [PDF]
Jong-Kook Lee, Jee-Eun Lee, Seong-Cheol Park, Hee-Dong Cho, Hye-Woong Yoo, Young-Sang Kim, Seong-Ryong Ryu, Woo-Suk Kim, Dong-Joon Ahn
Open Journal of Civil Engineering (OJCE) , 2015, DOI: 10.4236/ojce.2015.51014
Abstract: This study was performed to investigate the water repellent effectiveness of natural oil-applied soil when it is used as a building material. Natural oil types such as olive oil, bean oil, perilla oil and linseed oil, which are being used for producing water repellent timber, are selected for the experiments. It is expected that perilla oil and in seed oil, which are drying oil types will have better water repellent effectiveness than the other types. For the evaluation of water repellence of natural oil-applied soil, a contact angle test was performed. A contact angle of water drop on various surface conditions were tested, and large differences were seen between the natural oil-applied soil and untreated soil. As a result, it is showed that all natural oil types have water repellent effectiveness. However, linseed oil, which is a drying oil type, shows an outstanding water repellent effectiveness value, while perila oil, which is also a drying oil type, shows the lowest value. Additionally, results show that there is no link between water repellent effectiveness and the number of applications of natural oil. Nevertheless, existing commercial water repellents show better performance than natural oil, and it is anticipated that the results of this study will provide essential information for further research to enhance the water repellent effectiveness of soil as a building material.
Evaluation of Surface Roughness of Metal and Alloy Material  [PDF]
Joon-Seong Lee
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.41013

Turning clearance angle is changed machining characteristics. In this study, the experiments start from choosing two workpiece materials that are machine structural carbon steel, chrome-molyb- denum steel. Then, the experiments show specifically how features of selected materials changed when they were processed with machining operation. In order to find the surface roughness of workpiece materials, the workpiece materials which have higher tensile strength showed much better value of surface roughness in a surface roughness tester. Moreover, process feed rate was compared between 0.05 mm/rev and 0.10 mm/rev. When process feed rate was 0.05 mm/rev, surface roughness has superior results without reference to the quality of the materials.

Does Environmental Risk Affect Human Migration Behavior?  [PDF]
Seong Nam Hwang, Sang-Woo Lee
Journal of Geographic Information System (JGIS) , 2017, DOI: 10.4236/jgis.2017.94031
Abstract: This study tests the influence of environmental risks associated with floods, hurricanes, and hazardous material releases on human migration behavior. With close attention to a function of environmental risk factors, socio-demographic attributes, hazard risk and locational attributes were measured and correlated to the standardized number of recent arrivals and long term residents at the census tract level. Two groups (i.e., recent arrivals and long-term residents) were created to compare their moving behavior. The results indicate that flood risk showed little relationship to either recent arrivals or long-term residents. These results are consistent with past research which suggests that people tend to ignore their vulnerability to natural hazards. However, both groups had negative relationships to the risk from hurricanes and hazardous material releases. This counter-intuitive result suggests that other factors, such as proximity to employment opportunities or property tax advantages, need to be examined. In particular, the recent arrivals were negatively related to chemical risk while long-term residents were positively related to chemical risks, indicating that people that just arrived and old residents are somewhat different in perceiving environmental risks. In addition, the results of this study suggest that people are objective about environmental risks in selecting their habitat. However, once the habitat is settled, people’s perception of the risks may be interfered or reduced by other factors.
FE analysis of laminated composite plates using a higher order shear deformation theory with assumed strains
Lee, Sang Jin;Kim, Ha Ryong;
Latin American Journal of Solids and Structures , 2013, DOI: 10.1590/S1679-78252013000300005
Abstract: a study on the finite element (fe) analysis of laminated composite plates is described in this paper. in order to investigate structural behavior of laminated composite plates, a four-node laminated plate element is newly developed by using a higher order shear deformation theory (hsdt). in particular, assumed natural strains are introduced in the present fe formulation to alleviate the locking phenomenon. several numerical examples are carried out and its results are then compared with the existing reference solutions. it is found to be that the proposed fe is very effective to remove the locking phenomenon and produces reliable numerical solutions for most laminated composite plate structures.
The effects of Caffeoylserotonin on inhibition of melanogenesis through the downregulation of MITF via the reduction of intracellular cAMP and acceleration of ERK activation in B16 murine melanoma cells
Seong-Gene Lee
BMB Reports , 2012,
Abstract: In this study, we evaluated the anti-melanogenesis effects ofCaffeoylserotonin (CaS) in B16 melanoma cells. Treatment withCaS reduced the melanin content and tyrosinase (TYR) activity inB16 melanoma cells in a dose-dependent manner. CaS inhibitedthe expression of melanogenesis-related proteins, including microphthalmia-associated transcription factor (MITF), TYR, andtyrosinase-related protein-1 (TRP-1), but not TRP-2. α-MSH isknown to interact with melanocortin 1 receptor (MC1R) thusactivating adenylyl cyclase and increasing intracellular cyclicAMP (cAMP) levels. Furthermore, cAMP activates extracellularsignal-regulated kinase 2 (ERK2) via phosphorylation, whichphosphorylates MITF, thereby targeting the transcription factor toproteasomes for degradation. The CaS reduced intracellularcAMP levels to unstimulated levels and activated ERK phosphorylationwithin 30 min. The ERK inhibitor PD98059 abrogatedthe suppressive effect of CaS on α-MSH-induced melanogenesis.Based on this study, the inhibitory effects of CaS on melanogenesisare derived from the downregulation of MITF signaling viathe inhibition of intracellular cAMP levels, as well as accelerationof ERK activation.
Single-Molecule Sandwich Immunoassay for Quantification of Alpha-Fetoprotein Based on Evanescent Field-Enhanced Fluorescence Imaging
Seungah Lee,Seong Ho Kang
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/582531
Single-Molecule Sandwich Immunoassay for Quantification of Alpha-Fetoprotein Based on Evanescent Field-Enhanced Fluorescence Imaging
Seungah Lee,Seong Ho Kang
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/582531
Abstract: A highly sensitive immunosensor based on a gold nanopatterned chip was developed for accurate determination of alpha-fetoprotein (AFP) via total internal refection fluorescence microscopy (TIRFM). The surface of the gold nanopatterned chips was modified with dithiobis(succinimidyl propionate) and protein A/G for immobilization of the AFP antibody. The immunoassay created a sandwich of antigen between the AFP antibody on the chip that was modified with protein A/G, and the secondary antibody, a monoclonal anti-human-AFP labeled with biotin (biotin-labeled anti-AFP). AFP concentration was determined based on evanescent field fluorescence signal, which was generated by interaction between biotin-labeled anti-AFP and a streptavidin-labeled fluorescence dye. AFP concentration could be measured in a wide dynamic linear range of 720?zM–10?nM with a detection limit of 720?zM. A significant enhanced sensitivity (~40,000-fold) was achieved with the AFP-nanoarray chip compared to conventional chemiluminescence immunosensors. The immunoassay exhibited a wide detection range and high sensitivity and accuracy, qualities valuable for clinical assay of AFP. 1. Introduction Since the introduction of sandwich assays using monoclonal antibodies, various immunoassays have been introduced with automated analysis and increased specificity [1]. However, many immunoassay methods such as enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA), and single radial immunodiffusion have disadvantages such as being time-consuming procedures using expensive instrumentation with complicated separation and labeling steps, and potential dangers (e.g., radiation hazards) or expensive materials [2]. New techniques such as electrochemistry [3], chemiluminescence [4], piezoelectricity [5], surface plasmon resonance (SPR) [6], and sandwich immunoassays based on nanoarray protein chips [7, 8] have attracted interests because of their characteristics. Specifically, nanoarray protein chips offer a sensitive, accurate, quantitative, and simple alternative methodology for determination of tumor markers. Alpha-fetoprotein (AFP) is a 70?kDa oncofetal glycoprotein of 591 amino acids. It contains a single asparagine-linked (Asn233) carbohydrate chain that is a known biomarker for hepatocellular carcinoma (HCC) [9–12]. The association between serum AFP and HCC has been extensively described [13–16]. AFP has been a diagnostic test for HCC since the 1970s, when most patients with HCC were diagnosed at an advanced stage with clinical symptoms [17]. AFP is suggested to function as a transport
Towards Internet of Things (IOTS):Integration of Wireless Sensor Network to Cloud Services for Data Collection and Sharing
Rajeev Piyare,Seong Ro Lee
Computer Science , 2013, DOI: 10.5121/ijcnc.2013.5505
Abstract: Cloud computing provides great benefits for applications hosted on the Web that also have special computational and storage requirements. This paper proposes an extensible and flexible architecture for integrating Wireless Sensor Networks with the Cloud. We have used REST based Web services as an interoperable application layer that can be directly integrated into other application domains for remote monitoring such as e-health care services, smart homes, or even vehicular area networks (VAN). For proof of concept, we have implemented a REST based Web services on an IP based low power WSN test bed, which enables data access from anywhere. The alert feature has also been implemented to notify users via email or tweets for monitoring data when they exceed values and events of interest.
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