• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.2
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• pp.383-399
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• 1998

Tooth development is usually described in four stages such as bud stage, cap stage, bell stage and crown stage. Exact time of appearance of tooth primordia is different among reports, and up to now there is no timetable regarding initial tooth development. To understand the congenital malformations and other disorders of the orofacial region, there is a need to establish a standard timetable on early tooth development. Till now, studies on the tooth development were mainly on later fetuses, and only few reports on early stage. Also, there were no reports on the time when bud stage turns to cap stage, and cap stage to bell stage. In this study, external morphology of face and the early development of the tooth, and transition of bud stage to cap stage, cap stage to bell stage were studied using 27 staged human embryos and 9 serially sectioned human fetuses. The results are as follows: 1. Mandibular region was formed by union of both mandibular arch at stage 15, and maxillary region by union of maxillary arch, medial nasal prominence, and intermaxillary segment at stage 19. 2. Ectodermal thickening which represents the primordia of tooth appeared in mandibular region at stage 13, and maxillary region at stage 15. 3. Bud stage began from mandibular primary central incisor at stage 17, and maxillary primary central incisor at stage 18. And the sequence of appearance was in the mandibular primary lateral incisor at stage 19, maxillary primary lateral incisor at stage 20, mandibular primary canine at stage 22, maxillary primary canine and primary first molar at stage 23, madibular primary first molar and maxillary primary second molar at 9th week, and mandibular primary second molar at 10th week of development. 4. Cap stage began from the primary anterior teeth at 9th week, and primary second molar still had the characteristics of cap stage at 12th week of development. 5. Transition to bell stage started from the primary anterior teeth at 12th week, and primary second molar started at 16th week of development. 6. Trnasition to crown stage started from primary anterior teeth at 16th week, and primary second molar at 26th week of development.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.689-692
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• 2000

This paper presents a designing for the Off-line UPS usig SMB Flywheel Energy Storage System. This described flywheel energy storage system is designed to replace of the conventional EMB(Electro Mechanical Battery) system. To realize the high efficiency and to minimize the torque ripple the waveform of the inverter output current is controlled to be sinusoidal. The actual performance of the Off-line UPS using flywheel energy storage system is described. The prototype device was manufactured, The experimental result has good characteristics at a time of power transition region and regeneration modes,

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.603-606
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• 1998

In a large number of words and the continued speech recognition system using a phoneme as teh recognition unit, it is necessary to segment processing. In this paper, a normalized AMDF new method. The suggested parameter represents a degree of sharpness at valley point. This method can detect the speech segment between the steady state and transient region to the continued speech without a prior information of speech signal.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.08a
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• pp.392-395
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• 1998

기존의 DP 알고리즘을 이용하여 화자를 인식할 경우 시스템에 등록되어 있는 화자의 수가 증가할수록 처리해야할 데이터의 양이 많아진다. 그러므로 인식률이 저하되고 처리시간이 증가한다는 단점이 있다. 본 논문에서는 이러한 단점을 보완하기 위해 화자가 발성한 음성신호에서 안정구간내의 일정 파형을 삭제한 후 전이구간을 위주로 DP 알고리즘을 적용하여 화자를 인식한다. 제안한 방법으로 시험한 결과 시스템의 전체 인식률은 기존의 DP 알고리즘을 이용한 결과에 비해 1%의 향상을 보였고 처리시간은 21.6% 감소함을 볼 수 있다.

• Journal of The Korean Astronomical Society
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• v.21 no.2
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• pp.105-116
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• 1988

We have investigated hydrodynamical behaviors of spicules by solving numerically the hydrodynamic equations subject to proper boundary conditions using the method of characteristics. We examined the behaviors of MHD slow mode waves propagating through rigid magnetic flux tubes which were excited by the pressure perturbations at the lower boundary. It is found that the spicules are identified as the manifestation of the movement of the transition region being pushed upward by collisions with the shock waves. One of the most important findings is the presence of the rebound shocks and their roles. We interpreted the rebound shocks in terms of the observed recurrent spicules.

• Fibers and Polymers
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• v.7 no.2
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• pp.191-194
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• 2006

This paper adopts nonlinear vibration method to analyze the fluctuation process of fiber movement. Based on Hamilton Principle, this paper establishes differential equation of fiber axial direction movement. Using variable-separating method, this paper separates time variable from space variable. By using the disperse movement equation of Galerkin method, this paper also discusses stable region of transition curve and points out those influencing factor and variation trend of fiber vibration.

• Transactions of Materials Processing
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• v.18 no.1
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• pp.20-25
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• 2009

A finite element analysis was carried out for a 4:1 planar contraction die for polymer melts using the viscoelastic constitutive equation of Leonov. Viscoelastic fluids showed significant differences in pressure drop and birefringence in contraction and expansion flows. The pressure drop was higher and the birefringence smaller in expansion than in contraction flow. The difference increased with increasing flow rate. The nonlinear Leonov model was shown to describe the viscoelastic effects observed in experiments.

• Journal of East-Asian Urban History
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• v.1
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• pp.81-96
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• 2019

This paper attempts to rethink the ancient Emperor's Capital transition process from the viewpoint of territorial history. Emperor Tenmu, who planned first capital as Fujiwara-kyo in Asuka region, had a grand plan to put multiple cities in Japan. At that time the important cities were situated along east-west axis. However, since relocation of the capital from Fujiwara-kyo to Heijyo-kyo, the axis had turned towards north-south direction. The last ancient capital Heian-kyo was clearly organized utilizing north-south water systems in territorial sense.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.17-17
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• 2002

The magnetic effects connected to finite-size of the particles become dominant at transition of particles in region several nanometers and less [1]. At reduction of atom numbers in magnetic cluster (tens or hundreds atoms), along the classical features, essential appear the quantum phenomena resulting in spin transformation of magnetic structure, both with reduction of the size and at applying of an external magnetic field. (omitted)

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.50.4-50.4
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• 2019

We detect a new population of chromospheric jets in a polar coronal hole observed by Hinode/SOT. The propagating speed of the jets ranges in 30 - 490 km/s whose duration time is 3 - 52 s. The recurrent rate is approximately 3/min for a give segment of 1 arc-second horizontal interval. These jets are seemed to be more transient and faster than type II spicules at chromosphere, while the properties are compatible with the network jets seen in emission lines of transition region. We will discuss the implication of these jets for a coronal heating.