• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.822-828
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• 2001

Three-phase four-wire electrical distribution systems are widely employed in manufacturing plants, commercial and residential buildings. Due to the nonlinear loads connected to the distribution system, the neutral conductor carries excessive harmonic currents even under balanced loading since the triplen harmonics in phase currents do not cancel each other. This may result in wiring failure of the neutral conductor and overloading of the distribution transformer. In response to these concerns, a cost-effective neutral current harmonic suppressor system has been proposed [6]. This paper proposes an improved control method for the harmonic suppressor system under unbalanced load conditions. The proposed control method compensates for only the harmonic components in the neutral conductor, and the zero-sequence fundamental component due to unbalanced loading is prevented from flowing through the harmonic suppressor system. This remedies overloading and power loss of the system. The experimental results on a prototype validate the proposed control approach.

• Journal of the Korean Wood Science and Technology
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• v.19 no.3
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• pp.35-44
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• 1991

In this study, thickness 40mm glulams were composed of thickness 5mm, 10mm Quercus laminas and Pinus koraiensis laminas to study on the effect of load variation on transition of neutral axis of laminated veneer lumber(LVL). The transition of neutral axis was examined by strain variation, which was checked by strain gauge. amplifier, recorder, and strain meter. The elasticity of glulam was estimated by E = $\Sigma(E_i\;I_ i)$/I and this estimated elasticity values were compared with the elasticity values of glulam in bending. The result obtained can be summarized as follows: 1. The location of neutral axis of glulam was effected by glulam composition methods 2. The neutral axis did not shift by load variation within proportional limit. 3. The estimated elasticity of glulam by E = $\Sigma(E_i\;I_ i)$/I showed much lower value than the elasticity of glulam in bending.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.1
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• pp.59-64
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• 2003

This paper presents a new rotor position estimation method for brushless DC motors. The estimation error of the rotor position clearly provokes the phase shift angle misaligned between the phase current and the back-EMF waveforms, which causes torque ripple in brushless DC motor drives. Such an estimation error can be reduced with the help of the proposed neutral-voltage-based estimation method, which is structured as a closed loop observer. A neutral voltage appearing during the normal mode of the inverter operation is found to be an observable and control table measure, which can be used for estimating an exact rotor position. This neutral voltage is obtained from the DC-link current, the switching logic, and the motor speed values. The proposed algorithm, which can be easily implemented by using a single DC-link current and the motor terminal voltage sensors, is verified by simulation and experiment results.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.190-192
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• 2007

A neutral beam system has been developed to produce hyperthermal neutral beams composed of indium, tin, and oxygen atoms. Using these hyper thermal neutral beams with energies in the range of tens of eV, high quality indium-tin oxide (ITO) thin films have been obtained on glass substrates at room temperature. The optical transmittance of the films is higher than 85% at a wavelength of 550 nm and the electrical resistivity is lower than $1{\times}10^{-3}{\Omega}cm$.

• International Journal of CAD/CAM
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• v.7 no.1
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• pp.81-89
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• 2007

As the modular production is an important issue in globalized manufacturing industries, sub modules or parts of the final product are provided by many suppliers. Some part suppliers design their own products for themselves. In some cases, part supplier may provide the same type product to multiple 1-tier companies. Because all suppliers and 1-tier companies can not use the same CAD system in general case, the engineering change in the CAD model of one company could not propagate to related CAD models of other companies directly. Although they use the same CAD system, it is hard to share their CAD model with each other because of company security policy. In this paper, the neutral reference model, which consists of the neutral skeleton model and the external reference model, is proposed to apply a global top-down modeling approach to collaborating companies.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.2
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• pp.54-61
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• 2015

In 3-phase 4-wire inverter, the unbalanced loads cause to increase the neutral current which brings the voltage deviation between the split dc-link capacitors to be larger. In order to solve this problem, a neutral leg is provided additively to the ordinary inverter circuit and the associated control methods are devised. This paper proposes a new neutral-leg controller based on a PR controller and shows relatively good performance even under unbalanced linear loads and nonlinear loads. The proposed control strategy illustrates its effectiveness under the various operating conditions through simulation works.

• Journal of Korean Vacuum Science & Technology
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• v.7 no.1
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• pp.23-26
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• 2003

In this study, a neutral beam was formed using a low angle forward reflection of the ion beam and its degree of neutralization at different reflection angles was investigated. When the ion beam was reflected by a reflector at the angles lower than 15$^{\circ}$, most of the ions reflected were neutralized and the lower reflector angle showed the higher degree of neutralization. Photoresist(PR) and SiO$_2$ etchings were carried out with the neutralized oxygen and fluorine radical fluxes, respectively, and highly anisotropic etch profiles could be obtained suggesting the formation of highly directional neutral flux.

• Bulletin of the Korean Chemical Society
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• v.30 no.6
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• pp.1247-1251
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• 2009

The recognition of neutral aromatic substrates by different neutral calix[4]arene receptors 1, 2, and 3 was studied by NMR spectroscopy. The stoichiometry is 1:1 in all cases as was confirmed by jobs plot. Owing to the deep cavity, 1 affords stronger binding abilities for substrate 4 and 5, while all receptors remained inert for substrates 6 and 7. The binding constants determined by $^1H$ NMR titration show that the recognition of substrate 4 by 1 gives strongest complexation ($K_a\;of\;9.8\;{\times}\;102\;M^{-1}$).

• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.37-51
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• 2004

In this paper, we consider the asymptotic behavior of solutions of the forced nonlinear neutral difference equation $\Delta[x(n)-\sumpi(n)x(n-k_i)]+\sumqj(n)f(x(n-\iota_j))=r(n)$ with sign changing coefficients. Some sufficient conditions for every solution of (*) to tend to zero are established. The results extend and improve some known theorems in literature.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.151-152
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• 2000

During in door or outdoor mass culture, Porphyra have been easily contaminated with bacteria, protozoa and microalgal species. Several axenic treatments for Porphyra thalli have been published (Polne-Fuller and Gibo 1984; Chen and McCracken 1993), but axenic techniques for neutral spores and conchocelis we not developed. In this work we describe the procedure for axenic isolation of neutral spores and conchocelis of Porphyra yezoensis (omitted)