• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.241-245
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• 1998

This paper gives the novel design of compensated ring anode-short for power GTO thyristor. By means of this design the power GTO of $\Phi$63.5mm 2500A/4500V reaches more uniform turn-off compared with conventional ring short GTO, resulting in higher turn-off ability and low tail current/tail time.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.315-317
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• 2007

This paper proposes a loss minimization algorithm for doubly-fed induction generator (DFIG) by controlling the stator reactive power. The proposed strategy directly controls the rotor current to achieve the operating point of minimum generator loss and maximum power point tracking. The maximum power is obtained by tracking the q-axis rotor current with generator speed variation and the minimum generator loss is achieved by controlling the d-axis rotor current. Experimental results are shown to verify the validity of the proposed scheme.

• Journal of agriculture & life science
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• v.45 no.4
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• pp.105-112
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• 2011

Nutritional components and antioxidant activities of commercial loquat leaf tea (CLLT) were evaluated. Proximate compositions were as follows; moisture 5.34%, crude protein 8.38%, crude fat 13.26%, nitrogen free extract 46.21%, crude fiber 19.24% and crude ash 7.57%, respectively. Ascorbic acid and total phenolics content of CLLT was 0.47 mg/100 g and 42.55 mg/GAE g, respectively. Mineral elements were Ca 1,624.01 mg/100 g, K 1,099.66 mg/100 g, and Mg 192.70 mg/100 g, respectively. Amino acid contents of CLLT were very rich in glutamic acid 565.98 mg/100 g and deficient in cystine 12.97 mg/100 g. The 2,2'-azino-bis (3-ethylbenzthiazoline-6- sulfonic acid) diammonium salt (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities of hot water extract from CLLT were 72.51% and 90.11%, respectively at a concentration of $1,000{\mu}g/mL$. Reducing power and ferric reducing antioxidant power (FRAP) of hot water extract from CLLT were increased in a dose dependent manner. Therefore, these results suggest that the hot water extract of CLLT possess antioxidant activities and thus it has great potential as a source for functional food such as natural antioxidant.

• Advances in Energy Research
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• v.8 no.3
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• pp.185-202
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• 2022

This research work focuses to design and simulate a 200W solar power system with electrical power conservation scheme as well as thermal power conservation modeling to improve power extraction from solar power plant. Many researchers have been already designed and developed different methods to extract maximum power while there were very researches are available on improving solar power thermally and mechanically. Thermal parameters are also important while discussing about maximizing power extraction of any power plant. A specific type of coolant which have very high boiling point is proposed to be use at the bottom surface of solar panel to reduce the temperature of panel in summer. A comparison between different maximum power point tracking (MPPT) technique and proposed MPPT technique is performed. Using this proposed Thermo-electrical MPPT (TE-MPPT) with Deep Learning Algorithm model 40% power is conserved as compared to traditional solar power system models.

• Korean Journal of Food Science and Technology
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• v.46 no.2
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• pp.205-212
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• 2014

This study was designed to investigate the antioxidant activities (ORAC value, DPPH and ABTS radical scavenging activity, FRAP activity, and reducing power) and nitrite scavenging activities of Acanthopanax senticosus extracts fermented with the mycelia of three different mushroom species: Ganoderma lucidum, Phellinus linteus, and Hericium erinaceus. The highest total phenol content (42.09 GAE mg/g) and ORAC value ($74,912{\mu}M$ TE/g) were observed in a hot water extract of A. senticosus fermented with G. lucidum. The highest DPPH radical and nitrite scavenging activities were observed in a 70% ethanol extract of A. senticosus fermented with G. lucidum. In addition, ABTS radical scavenging activity (8-88%), FRAP activity (0.1-0.2), and reducing power (0.3-0.7) were increased by ethanol addition in all samples in a dose-dependent manner. These results provide a basic understanding of the antioxidant and nitrite-scavenging activities of A. senticosus extracts fermented with different mushroom mycelia.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.471-482
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• 2015

In this paper, design and implementation of the 94 GHz Gunn oscillator and the evaluation of the maximum power of the Gunn diode used in the oscillator are presented. The 94 GHz Gunn oscillator is used InP Gunn diode and designed employing a WR-10 waveguide. The designed oscillator is fabricated through machining and its performance is measured. The fabricated oscillator shows an oscillation frequency of 95 GHz, output power of 12.64 dBm, and phase noise of -92.7 dBc/Hz at 1 MHz offset frequency. To evaluation the maximum power of the InP Gunn diode used in oscillator, the oscillator structure is modified to a structure having a diaphram. The height of thick diaphram which is used in the oscillator is varied. As a result, an oscillator has several different load impedances, which makes it possible to plot $G_L-V^2$ plot at the post plane. Using the $G_L-V^2$ plot, the maximum power of used Gunn diode including post is computed to be 16.8 dBm. Furthermore using the shorted and zero bias Gunn diode, the post loss used for DC biasing can be computed. Using the two losses, The maximum power of a InP Gunn diode is computed to be 18.55 dBm at 95 GHz. This result is close to a datasheet.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.417-428
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• 2020

Investigations of the commercial aircraft impact effect on nuclear island infrastructures have been drawing extensive attention, and this paper aims to perform the safety assessment of Generation III nuclear power plant (NPP) buildings subjected to typical commercial aircrafts crash. At present Part III, the local damage of the rigid components of aircraft, e.g., engine and landing gear, impacting the steel concrete (SC) structures of NPP containment is mainly discussed. Two typical SC target panels with the thicknesses of 40 mm and 100 mm, as well as the steel cylindrical projectile with a mass of 2.15 kg and a diameter of 80 mm are fabricated. By using a large-caliber air gas gun, both the projectile penetration and perforation test are conducted, in which the striking velocities were ranged from 96 m/s to 157 m/s. The bulging velocity and the maximal deflection of rear steel plate, as well as penetration depth of projectile are derived, and the local deformation and failure modes of SC panels are assessed experimentally. Then, the commercial finite element program LS-DYNA is utilized to perform the numerical simulations, by comparisons with the experimental and simulated projectile impact process and SC panel damage, the numerical algorithm, constitutive models and the corresponding parameters are verified. The present work can provide helpful references for the evaluation of the local impact resistance of NPP buildings against the aircraft engine.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.261-264
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• 1997

Joints and terminations for 345kV Oil Filled $1C{\times}2000mm^2$ cable have been developed and tested including BPT (Bellows Pressure Tank) on the bases of various ultra-high voltage technologies. Electrical design was performed by using Finite Element Method. The type test certified by KEPCO (Korea Electric Power Corporation) has been performed as the final stage of development. In order to confirm the reliability of long-term life for 30 years, load cycle test was conducted for 30 days with good result. As the result, the techniques we obtained from this development are applicable to higher voltage level systems (i.e. 765 kV).

• 프린팅코리아
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• s.16
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• pp.94-95
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• 2003

• Korean Journal of Mathematics
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• v.30 no.2
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• pp.391-402
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• 2022

For a given graph G = (V, E), a dominating set is a subset V' of the vertex set V so that each vertex in V ＼ V' is adjacent to a vertex in V'. The minimum cardinality of a dominating set of G is called the domination number of G and is denoted by γ(G). For an integer k ≥ 1, the k-th power G^k of a graph G with V (G^k) = V (G) for which uv ∈ E(G^k) if and only if 1 ≤ d_G(u, v) ≤ k. Note that G² is the square graph of a graph G. In this paper, we obtain some tight bounds for the sum of the domination numbers of a graph and its square graph in terms of the order, order and size, and maximum degree of the graph G. Also, we characterize such extremal graphs.