• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.183-199
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• 2007

In this paper we research the problem in which the objective is to minimize the sum of squared deviations of job expected completion times from the due date, and the job processing times are stochastic. In the problem the machine is subject to stochastic breakdowns and all jobs are preempt-repeat. In order to show that the replacing ESSD by SSDE is reasonable, we discuss difference between ESSD function and SSDE function. We first give an express of the expected completion times for both cases without resampling and with resampling. Then we show that the optimal sequence of the problem V-shaped with respect to expected occupying time. A dynamic programming algorithm based on the V-shape property of the optimal sequence is suggested. The time complexity of the algorithm is pseudopolynomial.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.441-444
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• 2009

Weldlines are generated during the injection molding process when two or more melt flows are brought into contact. At the welded contact region, a 'V'-shaped notch is formed on the surface of the molded part. This 'V'-notch deteriorates not only surface appearance but also mechanical strength of the molded part. To eliminate or reduce weldlines so as to improve the weldline strength, the mold temperature at the corresponding weld locations should be maintained higher than the glass transition temperature of the resin material. The present study implements high-frequency induction heating in order to rapidly raise mold surface temperature without a significant increase in cycle time. This induction heating enables to local mold heating so as to eliminate or reduce weldlines in an injection-molded plastic part. The effect of induction heating conditions on the weldline strength and surface appearance of an injection-molded part is investigated.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.5
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• pp.203-206
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• 2001

The applicability of shaped growth of yttrium orthovanadate was approved by successful growth of rod-like single crystals with the rectangular shape. Nd-doped single crystals with content of $Nd^{3+}$ ions of 1,2,3,5 atomic % in the starting melt were grown by the EFG technique with the size up to $10^{*}10mm$ in section and up to 85 mm in length. For the testing of the multiple growth of the orthovanadates, two and three Nd-and Yb-doped $YVO_{4}$ single crystals were grown by the EFG technique simultaneously up to 110 mm in length.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.334-337
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• 1997

This paper describes dielectric characteristics of SF$_{6}$ gas stressed by the non-oscillating and oscillating impulse voltages in inhomogeneous fields disturbed by metallic protrusion. The breakdown voltage-time (V-t) characteristics and breakdown voltage-gas pressure (V-p) characteristics and their characteristics are statistically investigated with positive and negative very fast transient overvoltages. The experiments were carried out using a needle-to-plane gap geometry in the gas pressure ranges from 0.1 to 0.5 MPa. The gap separation gas 22 mm, and the needle-shaped protrusions were made of stainless steel 10 mm in length and 1.0 mm in diameter.r.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.454-457
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• 2008

We report the syntheses, photophysical properties and device performances of solution processible host material for green-phosphorescent OLEDs. The butterfly-shaped new host materials with nonconjugated linkage of carbazole and fluorene moieties have large triple energy band gap around 2.8 eV. All of the EL devices exhibited turn-on voltages in the range of 4.8-5.0 V. GH-4 exhibited the best performance with a maximum current efficiency and power efficiency of 21.1 cd/A and 7.9 lm/W.

• Transactions on Electrical and Electronic Materials
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• v.1 no.1
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• pp.1-5
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• 2000

Diamond films have been achieved on Si(100) substrates using helicon plasma chemical vapor deposition(HPCVD), Gas mixtures with methane and hydrogen have been used. The growth characteristics were investigated by means of X-ray photoelectroton spectroscopy, Atomic force microscopy and X-ray diffraction. We obtained a plasma density as high as 10$\^$10/~10$\^$11/ cm$\^$-3/ by helicon source. The smooth(100) faces of submicron diamond crystallites were found to exhibit pyramidal shaped architecture, The XPS spectrum for the nucleation layer indicates the presence of diamond at 285.4 eV, close to the reported value of 285.5 eV for diamond , XRD results demonstrates the existence of polycrystalline diamond as the diamond (111) and (220) peaks.

• ALGAE
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• v.30 no.2
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• pp.81-87
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• 2015

Recent studies have shown the importance of viruses as potential sources of plankton mortality, which affect primary production and biogeochemical functions of their hosts. Here, we report basic characteristics of a novel virus (Stephanopyxis palmeriana virus: SpalV) that causes lysis of a culture of the diatom S. palmeriana, which was isolated in Jaran Bay, Korea, in August 2008. SpalV is a round-shaped viral particle ~25-30 nm in diameter that propagates in its host's cytoplasm. In addition, it shows species-specific infectivity among the tested diatom species. The burst size and latent period are estimated to be roughly 92 infectious units $cell^{-1}$ and <80 h, respectively.

• Journal of Powder Materials
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• v.13 no.2 s.55
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• pp.108-111
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• 2006

Aluminum hydroxides were synthesized by a simple electrolytic reaction of aluminum plates. The aluminum hydroxide, boehmite (AlO(OH)), was predominantly formed in the application of electrical potential at and above 30V, while the mixture of bayerite ($Al(OH)_3$) and boehmite (AlO(OH)) phases were formed below 20V. The boehmite has a clear fibrous structure controlled on nanometer scale. On the contrary, the bayerite consists of the typical hourglass or semi-hourglass shaped coarse crystals as a result of aggregation of various crystals stacked together. The specific surface area of the boehmite nanofiber was markedly high, approaching at about $302\;m^2/g$.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.123-125
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• 2005

The purpose of this paper is to optimize rotor shape of interior permanent magnet (IPM) motor for high torque. V-shaped permanent magnet arrangement is applied to obtain more torque than prototype IPM. The performance, based on finite element method, is evaluated as torque per rotor volume (TRV). In this paper, response surface methodology (RSM) is used to search optimal shape of the rotor. The usefulness of RSM in optimal design of IPM motor is verified by comparing TRV between prototype and optimized V-type.

• Journal of The Korean Astronomical Society
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• v.28 no.2
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• pp.177-196
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• 1995

We present UBV CCD photometry of the double cluster NGC 1850 located at the NW edge of the bar of the Large Magellanic Cloud. The color-magnitude diagram shows that NGC 1850 has a prominent population of massive core-He burning stars which is incomparably richer than any other known star clusters. The reddening is estimated from the (U-B) - (B-V) diagram to be E(B - V) = $0.15{\pm}0.05$. We have estimated the ages of NGC 1850 and a very compact blue star cluster (NGC 1850A) located at ${\sim}30''$ west of NGC 1850 using isochrones based on the convective overshooting models: $80{\sim}10$ Myrs and $5{\sim}2$ Myra, respectively. Several evidence suggest that it is probably the compact cluster NGC 1850A that is responsible for the arc-shaped nebulosity (Henize N 103B) surrounding the east side of NGC 1850.