• Journal of Power Electronics
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• v.18 no.5
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• pp.1458-1469
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• 2018

This paper proposes a novel common-mode voltage (CMV) elimination (CMV-EL) method based on model predictive control (MPC) to eliminate CMV for three-level T-type inverters (3LT2Is). In the proposed MPC method, only six medium and one zero voltage vectors (VVs) (6MV1Z) that generate zero CMV are considered as candidates to perform the MPC. Moreover, the influence of dead-time effects on the CMV of the MPC-based 6MV1Z method is investigated, and the candidate VVs are redesigned by pre-excluding the VVs that will cause CMV fluctuations during the dead time from 6MV1Z. Only three or five VVs are included to perform optimization in every control period, which can significantly reduce the computational complexity. Thus, a small control period can be implemented in the practical applications to achieve improved grid current performance. With the proposed CMV-EL method, the CMV of the $3LT^2Is$ can be effectively eliminated. In addition, the proposed CMV-EL method can balance the neutral point potentials (NPPs) and yield satisfactory performance for grid current tracking in steady and dynamic states. Simulation and experimental results are presented to verify the effectiveness of the proposed method.

• Journal of Korean Society of Forest Science
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• v.88 no.1
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• pp.86-92
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• 1999

Evapotranspiration is one of important variables affecting ecosystem processes such as vegetation distribution and growth. It acts as a limiting factor for natural water resource management. The transpiration of vegetation is mainly determined by climatic factors. The lower slope of the study area was densely forested with Pinus densiflora S. et Z. of 8 m height, and the upper slope was covered with poorly grown Pinus densiflora S. et Z. and Quercus trees. The amount of evapotranspiration was estimated to 590.3 mm/yr by annual water budget method. The canopy resistance of Penman-Monteith model was determined as 99 s/m. Seasonal evapotranspiration can be estimated with the calculated evaporation and the canopy resistance. The amount of evapotranspiration peaked in May. That is considered from both the direct evaporation of intercepted rainfall and the transpiration of vegetation during the dry spring season.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.91-91
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• 2012

We present high-resolution near-infrared host galaxy spectra of low-z quasars, PG0844+349 (z=0.064), PG1226+023 (z=0.158), and PG1426+015 (z=0.086). The observation was done by using the near-IR high resolution echelle spectrometer, IRCS, at the SUBARU 8.2 m telescope. The full width at half maximum of the point spread function was about 0.3 arcsec by using an Adaptive Optics system, which can effectively resolve the quasar spectra from the host galaxy spectra. The signal-to-noise ratios are increased by the total exposure time up to several hours per targets and the development of data reduction method. We compare our results to the stellar spectra library and sample spectra from Dasyra et al. (2007) and Watson et al. (2008). The identified spectral lines will be used to study the physical mechanism of quasars, and the velocity dispersions of the stars in the bulge of the host galaxy.

• Current Applied Physics
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• v.18 no.12
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• pp.1523-1527
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• 2018

The thermal stability, magnetic and magnetocaloric properties of $Gd_{55}Co_{35}M_{10}$ (M = Si, Zr and Nb) melts-pun ribbons were studied. The relatively high reduced glass transition temperature ($T_{x1}/T_m$ > 0.60) and low melting point ($T_m$) resulted in excellent glass forming ability (GFA). The Curie temperatures ($T_C$) of melt-spun amorphous ribbons $Gd_{55}Co_{35}M_{10}$ for M = Si, Zr and Nb were 166, 148 and 173 K, respectively. For a magnetic field change of 2 T, the values of maximum magnetic entropy change $(-{\Delta}S_M)^{max}$ for $Gd_{55}Co_{35}Si_{10}$, $Gd_{55}Co_{35}Zr_{10}$ and $Gd_{55}Co_{35}Nb_{10}$ were found to be 2.86, 4.28 and $4.05J\;kg^{-1}K^{-1}$, while the refrigeration capacity (RC) values were 154, 274 and $174J\;kg^{-1}$, respectively. The $RC_{FWHM}$ values of amorphous alloys $Gd_{55}Co_{35}M_{10}$ (M = Si, Zr and Nb) are comparable to or larger than that of $LaFe_{11.6}Si_{1.4}$ crystalline alloy. Large values of $(-{\Delta}S_M)^{max}$ and RC along with good thermal stability make $Gd_{55}Co_{35}M_{10}$ (M = Si, Zr and Nb) amorphous alloys be potential materials for magnetic cooling operating in a wide temperature range from 150 to 175 K, e.g., as part of a gas liquefaction process.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.103.1-103.1
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• 2012

We present the results of SDSS r, i and z band photometry for HBC722 (also known as $LkH{\alpha}$ 188 G4, PTF10qpf and V2493 Cyg), with Camera for Quasars in Early uNiverse (CQUEAN) attached to 2.1m Otto Struve telescope at McDonald Observatory, USA. HBC722 is a newly erupted FU Orionis type object, which produced optical outburst (${\Delta}V$=4.7 mag) over a year that peaked in 2010 September. We carried out the monitoring observations during 48 nights from 2011 April to 2012 June to check the short-term and the long-term variabilities for chasing the Keplerian rotation of the system. Comparing the photometric results of r, i and z band, we describe the color variability which is related to the physical properties of the system like circumstellar disk and accretion process.

• Journal of Pharmacopuncture
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• v.18 no.1
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• pp.7-18
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• 2015

Objectives: Loranthus ferrugineus (L. ferrugineus) from Loranthaceae, a mistletoe, is a medicinal herb used for a variety of human ailments. Traditionally, decoctions of this parasitic shrub have been mainly used to treat high blood pressure (BP) and gastrointestinal complaints; usage which is supported by experimental based pharmacological investigations. Nonetheless, there is still limited data available evaluating this plant's traditions, and few studies have been scientifically translated toward evidence based phytomedicine. We therefore provide a concise review of the currently available L. ferrugineus literature and discuss potential directions for future areas of investigation. Methods: We surveyed available literature covering ethnopharmacological usage of L. ferrugineus and discussed relevant findings, including important future directions and shortcomings for the medicinal values of this parasitic shrub. Results: Evidence based pharmacological approaches significantly covered the medicinal application of L. ferrugineus for hypertension and gastrointestinal complaint management, with a particular focus on the active hydrophilic extract of this herb. Conclusion: Understanding the sites of action of this plant and its beneficial effects will provide justification for its use in old traditional treatments, and potentially lead to the development of therapies. Other medicinal applicative areas of this parasitic shrub, such as wound healing, gerontological effects, and antiviral and anticancer activities, are yet to be researched.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.83.2-83.2
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• 2012

Type I AGNs are classified by the presence of broad emission lines while Type II AGNs show narrow emission lines only. All-sky surveys such as SDSS provide large AGN samples for statistical studies. However, the AGN samples suffer selection bias due to the incomplete selection criteria. To investigate the missing Type I AGNs in optical spectroscopic surveys, we start with a sample of SDSS Type II AGNs at 0.02 < z < 0.05, using the MPA-JHU SDSS DR7 catalog. We search for the hidden broad $H{\alpha}$ component with both visual inspection and the multi-component spectral decomposition method. Out of 1383 Type II AGNs, we find a total of 62 missing Type I AGNs (~4.5%). The sample has mean black hole mass, log $(M_{BH}/M_{SUN))=6.48{\pm}0.53$, and luminosity, log $(L_{H{\alpha}}/ergs^{-1})=40.52{\pm}0.33$, with Eddington ratio, log $(L_{bol}/L_{Edd})=-1.51{\pm}0.41$. We will describe the sample and present the $M_{BH}-{\sigma}_*$, and $M_{BH}-M_*$ relations of the sample in the context of the BH-galaxy coevolution.

• Bulletin of the Korean Mathematical Society
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• v.47 no.2
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• pp.275-286
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• 2010

The algebraic structure of the natural integral cohomology operations is explored by means of examples. We decompose the generators of the groups $H^m(\mathbb{Z},\;n)$ with $2\;{\leq}\;n\;{\leq}\;7$ and $2\;{\leq}\;m\;{\leq}\;13$ into the operations of cup products, cross-cap products and compositions. Examination of these decompositions and comparison with other possible generators demonstrates the existence of relations between integral operations that have withheld formulation. The calculated groups and generators are collected in a table for practical reference.

• 한국균학회소식:학술대회논문집
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• 2009.10a
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• pp.38-40
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• 2009

• Bulletin of the Korean Mathematical Society
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• v.54 no.5
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• pp.1725-1741
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• 2017

For a complex smooth projective surface M with an action of a finite cyclic group G we give a uniform proof of the isomorphism between the invariant $H^1(G,\;H^2(M,\;{\mathbb{Z}}))$ and the first cohomology of the divisors fixed by the action, using G-equivariant cohomology. This generalizes the main result of Bogomolov and Prokhorov [4].