• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.808-809
• /
• 2008

22.9kV 50MVA HTS power cable has been developed and tested by Korea Electrotechnology Research Institute and LS Cable Company and it was supported by a grant from Center for Applied Superconductivity Technology of the 21st Century Frontier R&D Program. In this paper, DC Ic of 100m HTS cable which is installed at Kochang testing station was measured and analyzed. A measurement technique of DC Ic used by resistance and inductance removal method is established. The HTS power cable is composed of 2 layers for transmission and 1 layer for shield. For the analysis of AC losses in an HTS power cable, 2-dimensional numerical calculation was carried out to define the magnetic field distribution. We calculated the magnetization losses in the HTS core of that cable from these fields. These calculated results are in accordance with those of experiment.

• International Journal of Computer Science & Network Security
• /
• v.23 no.9
• /
• pp.162-165
• /
• 2023

Power can be generated from either renewable or non-renewable sources. Renewable sources are liked to maintain a strategic distance from contamination emanation and rely on upon fossil energizes which is decreasing day by day. The proposed sun powered vitality transformation unit comprises of a sun oriented exhibit, Bidirectional DC-DC converter, single stage inverter and AC. The inverter changes over DC control from the PV board into AC power and offered it to the heap which is associated with the lattice. The photovoltaic sun powered vitality (PV) is the most direct approach to change over sunlight based radiation into power and depends on the photovoltaic impact. The most extreme power point following of the PV yield for all daylight conditions is a key to keep the yield control per unit cost low for fruitful PV applications. Framework associated PV frameworks dependably have an association with people in general power matrix by means of an appropriate inverter in light of the fact that a PV module conveys just dc power. This project presents the new design, Development and Performance Analysis of a Grid Connected PV Inverter. Demonstrate that the proposed framework can lessen the Energy Consumption radically from the power board and give a solid support to the Grid.

• Progress in Superconductivity and Cryogenics
• /
• v.11 no.3
• /
• pp.46-49
• /
• 2009

A 3-phase 100m long, 22.9kV class HTS power transmission cable system was developed by Korea Electrotechnology Research Institute (KERI) and LS cable Ltd. those are participated in the 21st Century Frontier project R&D Program of Korea. It is important to test the DC critical current related with its power capacity before applying to the real power grid. In 1995, several international standards organizations including International Electrotechnical Commission (IEC), decided to unify the use of statistical terms related with 'accuracy' or 'precision' in their standards. It was decided to use the word 'uncertainty' for all quantitative (associated with a number) statistical expressions. In this paper, we measured DC critical current of 22.9kV/50MVA superconducting power cable with several voltage tap and analyzed the uncertainty with these results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.5
• /
• pp.453-458
• /
• 2010

In this work, a 18 GHz divide-by-4 injection-locked frequency divider(ILFD) based on ring oscillator has been developed in $0.13-{\mu}m$ Si RFCMOS technology. The free-running oscillation frequency is from 4.98 to 5.22 GHz and output power is about －30 dBm, consuming 33.4 mW with a 1.5 V supply voltage. At 0 dBm input power, the locking range is 3.5 GHz(17.75~21.25 GHz) and with varactor tuning, the operating range is increased up to 5.25 GHz(16.0~21.25 GHz). The fabricated chip size is $0.76\;mm{\times}0.57\;mm$ including DC and RF pad.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.2
• /
• pp.202-209
• /
• 2018

This study analyzed the effects of the nutrient intake on oral health and chewing difficulty according to the age group. The subjects were 5,855 participants of the third Korea National Health and Nutrition Examination Survey(KNHANES VI), 2015, Korea Centers for Disease Control and prevention and aged 20 years and over. The data were analyzed using SPSS Ver 21.0, classified as the difficulty in chewing group (DC) and no difficulty in chewing group (NDC). As a result, the DC rates were 5 times higher in the 60+ year age group (39.5%) than in the 20-39 year age group (8.1%). The DC group were experience periodontal disease (33.4%), dental caries (30.1%), diabetes (41.8%), myocardial infarction (57.3%), arthritis (44.0%), asthma (48.0%), and depression (41.9%). In addition, 86% of the DC group were experiencing speech problems. The DC group had significantly lower intakes (1446.59g), than the NDC group (1666.62g), and the protein, carbohydrate, dietary fiber and other dietary intake were significantly lower. These findings suggest that the chewing difficulty is related to the nutrient intake, and psychological status in the elderly DC group. Therefore, the care of chewing difficulties is essential for the elderly to maintain a healthy lifestyle. Accordingly, oral care and myofunctional therapy are needed to maintain oral health.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.41 no.12
• /
• pp.7-12
• /
• 2004

In this paper, CPW wideband distributed amplifier was designed and fabricated using 0.1 $\mum$ InGaAs/InAlAs/GaAs Metamorphic HEMT(High Electron Mobility Transistor). The DC characteristics of MHEMT are 442 mA/mm of drain current density, 409 mS/mm of maximum transconductance. The current gain cut-off frequency(fT) is 140 GHz and the maximum oscillation frequency(fmax) is 447 GHz. The distributed amplifier was designed using 0.1 $\mum$ MHEMT and CPW technology. We designed the structure of CPW curve, tee and cross to analyze the discontinuity characteristics of the CPW line. The MIMIC circuit patterns were optimized electromagnetic field through momentum. The designed distributed amplifier was fabricated using our MIMIC standard process. The measured results show S21 gain of above 6 dB from DC to 45 GHz. Input reflection coefficient S11 of -10 dB, and output reflection coefficient S22 of -7 dB at 45 GHz, respectively. The chip size of the fabricated CPW distributed amplifier is 2.0 mm$\times$l.2 mm.

• Parasites, Hosts and Diseases
• /
• v.54 no.3
• /
• pp.281-289
• /
• 2016

Clonorchis sinensis is a Group-I bio-carcinogen, associated with cholangiocarcinoma (CCA). The hamster is the only experimental model of C. sinensis-mediated CCA, but we oblige another animal model. The present study intended to develop a C. sinensis (Cs) mediated CCA model using C3H/He mice, co-stimulated with N-nitrosodimethylamine (NDMA) and dicyclanil (DC). The mice were divided into 8 groups with different combinations of Cs, NDMA, and DC. Six months later the mice were sacrificed and subjected to gross and histopathological examination. The body weights were significantly reduced among the groups treated with 2 or more agents (eg. Cs+NDMA, Cs+DC, NDMA+DC, and Cs+NDMA+DC). In contrast, liver weight percentages to body weight were increased in above groups by 4.1% to 4.7%. A Change of the spleen weight was observed only in Cs+NDMA group. Though C. sinensis infection is evident from hyperplastic changes, only 1 worm was recovered. Two mice, 1 from Cs and the other from Cs+DC group, showed mass forming lesions; 1 ($281.2mm^3$) from the Cs group was a hepatocellular adenoma and the other ($280.6mm^3$) from the Cs+DC group was a cystic mass (peliosis). Higher prevalence of gray-white nodules was observed in Cs group (42.9%) followed by Cs+NDMA+DC group (21.4%). The mice of the Cs+NDMA+DC group showed hyper-proliferation of the bile duct with fibrotic changes. No characteristic change for CCA was recognized in any of the groups. In conclusion, C3H/He mice produce no CCA but extensive fibrosis when they are challenged by Cs, NDMA, and DC together.

• Journal of the Korean Vacuum Society
• /
• v.16 no.4
• /
• pp.291-297
• /
• 2007

The field emission properties of CNT-emitters coated with Ag-Cu alloy have been investigated. The vertical aligned multi-walled CNTs were synthesized by dc-plasma enhanced chemical vapor deposition (dc-PECVD) and the Ag-Cu alloy was coated by using dc-magnetron sputter. The morphology of alloy-coated and un-coated CNT-emitters was observed by using SEM and their field emission properties were also measured. Annealing the AgCu-coated CNTs at temperature more than ${\sim}700^{\circ}C$, the Ag-Cu alloy was diffused to and aggregated on the top of the CNT as a Q-tip. A significant progress on the field emission was not observed with coating Ag-Cu alloy on the CNTs, but a certain improvement in a resistance against oxygen gas was made confirmation. It seems to be due to inertness of Ag-Cu alloy on the CNTs.

• Food Science and Preservation
• /
• v.21 no.3
• /
• pp.427-433
• /
• 2014

Ethanol and hot water extracts were prepared from Lindera obtusiloba Blume (LO) and Zanthoxylum piperitum DC (ZP) and used to evaluate their antimicrobial activities and thermal stability against six foodborne pathogens (3 gram-positive and 3 gram-negative bacteria). The antimicrobial activities were assessed using the agar diffusion method, and the thermal stabilities of extracts were examined after heat treatment at 60, 70, 80, and $100^{\circ}C$ for 10 min. The zones of inhibition by the LO extract or the ZP extract of the tested microorganisms were in the range of 21-30 mm and 19-25 mm, respectively, at 100 mg/mL concentrations. The 60% ethanol extract and the hot water extracts from LO showed the strongest antimicrobial effects against MRSA and Staphylococcus aurues, respectively. For the extract from ZP, the strongest antimicrobial effect was shown against S. aurues by 60% ethanol, and the weakest antimicrobial effect was shown against E. coli by the hot water extracts. The ZP extracts showed that the gram-positive bacteria were more sensitive than gram-negative bacteria. For the thermal stability of the extracts, the antimicrobial effects stabilized after heat treatment. Overall, the data suggest that the extracts have a potential for application in various food products for which a natural antimicrobial additive is desired.

• Journal of Aquaculture
• /
• v.18 no.3
• /
• pp.180-188
• /
• 2005

The separation performances for thirty different dimensions of a low-pressure hydrocyclone (LPH) were tested in order to obtain an optimum dimension scale for fecal solid removal from an aquaculture system. The geometric variables were considered on two inlet diameters (Di: 30 and 50 mm), five overflow diameters (Do: 30, 50, 60, 70 and 100 mm), and three cylinder lengths (Lc: 250, 345 and 442 mm), while the cylinder diameter (Dc) of 335 mm, underflow diameter (Du) of 50 mm and cone angle (${\theta}$) of $68^{\circ}$ were kept constant. A small size for carp feces was regarded as the target for the removal of solids. Spherical polystyrene particles (1.1-1.3 mm dia., ${\rho}_s=1.05g/cm^3$), which demonstrate a similar settling velocity and specific gravity to the carp feces, were used as feed. The separation performance was tested in the range of 330 to 1200 ml/s of the inflow rate. Experimental results using ANCOVA and the Tukey test (${\alpha}=0.05$) demonstrated that the separation performances of LPH were significantly affected (P<0.05) by fi, Di and Do. In contrast, there was no significant Lc effect (P>0.05) on the separation performances. The maximum separation performance was detected at dimension combinations of 30 mm of inflow diameter (Di), 50, 60 and 70 mm of overflow diameter (Do), 345 mm of cylinder length (Lc). The dimension proportions were 0.09, 1.03, 0.15-0.21 and 0.15 (or Di/Dc, Lc/Dc, Do/Dc and Du/Dc, respectively.