• 대한소아치과학회지
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• 제43권3호
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• pp.284-291
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• 2016

본 연구는 이소맹출한 상악 제1대구치의 자율적 수정 가능성을 예측할 수 있는 진단적 기초를 제공하기 위하여 정상군과 가역성과 비가역성 이소맹출의 차이점을 비교 평가하고자 후향적으로 분석하였다. 상악 제1대구치와 인접치아 간의 장축과 교합평면간의 각도를 파노라마상에서 측정하였고, 제2유구치의 교합관계도 조사하였다. 이소맹출군과 정상군은 통계학적으로 유의한 차이를 보였지만(p < 0.05), 가역성과 비가역성 이소맹출군 간에는 통계학적으로 유의한 차이는 없었다(p > 0.05). 제2유구치와 제1대구치 그리고 제2대구치 치배 간의 각도는 정상군에 비해 이소맹출 군에서 작은 값을 보였으며, 근심 계단형이 이소맹출군에서 더 높은 빈도로 관찰되었다. 본 연구의 결과를 토대로 상악 제1대구치의 이소맹출은 상악 제1대구치와 제2대구치 치배의 각도와 관련이 있으며, 이소맹출한 상악 제1대구치는 상악 저성장의 3급 부정교합 환자에서 보다 빈번하게 나타나는 경향이 있는 것을 알 수 있었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권6호
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• pp.462-466
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• 2009

Purpose: Dentigerous cyst is the most common intra-osseous lesion of the jaw. Dentigerous cysts can cause delays in eruption of the affected permanent tooth in mixed dentition. It has been suggested that the affected permanent tooth could be erupted spontaneously after the dentigerous cyst was enucleated. But in some cases, orthodontic treatment or autotransplantation technique is known to be required. This study reviews previously performed prognoses of affected permanent teeth, which will lead to a more efficient treatment plan. Patients and Methods: With 28 patients who have undergone cyst enucleation and 10 patients who have undergone autotransplantation, the prognosis of permanent teeth was observed. Results: After cyst enucleation, spontaneous eruption of a permanent tooth was observed in 56.3% patients, orthodontic treatment was performed in 25% patients. The success rate of autotransplantation was 60.0%. Discussion: The first choice for treatment of dentigerous cyst in mixed dentition is to guide spontaneous eruption of permanent teeth. For cases without enough eruption space, the orthodontic treatment should be considered. Autotransplantation should be considered when the spontaneous eruption is not expected. It should be considered that the rate of successful autotransplantation is decreased on maxilla anterior area.

• 한국도로학회논문집
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• 제13권4호
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• pp.41-50
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• 2011

일반적으로 도로 포장체의 파손은 다양한 요소에 영향을 받는 것으로 알려져 있다. 그 중 가장 주된 포장체 파손형태로서 영구변형(permanent deformation)과 피로균열(fatigue crack)을 들 수 있으며 이들은 포장체의 공용수명을 단축시키는 주요원인이 된다. 도로 포장체의 영구변형을 정확히 예측하는 것은 도로포장체의 내구성을 파악하여 이를 기반으로 포장을 설계하는 포장설계법의 수립에 있어 매우 중요하다. 포장하부구조의 재료거동은 본질적으로 전단강도(${\tau}_{max}$)와 밀접한 연관성을 가지므로 포장하부구조 내 발생한 전단응력${\tau}$의 전단강도에 대한 발생비를 고려하여 영구변형 모델을 설정할 필요가 대두되고 있다. 이에 본 연구에서는 이와 같은 전단응력비 개념을 도입한 대형반복삼축압축시험을 통하여 도로하부 재료 중 국내에서 사용되는 대표적인 입상의 보조기층 재료에 대한 영구변형 특성을 알아보았으며 이를 기초로 영구변형 모델의 수립에 필요한 모델 매개변수를 시험을 통해 새롭게 제안하고자 하였다.

• Progress in Superconductivity
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• 제12권2호
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• pp.93-98
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• 2011

Pinning force is the mechanism between a superconductor and a permanent magnet and it provides a stable levitation. However, when external force greater than the pinning force such as the earthquake exerts, the levitated object may lose the levitating characteristic. In order to achieve more stabilized levitation, the copper plate was inserted in between a superconductor and permanent magnets. And by applying the eddy current effect caused from the relationship between a copper plate and permanent magnets, more stabilized levitation can be established. In this study, an optimized design was found based on various configurations of permanent magnet's polarity, thickness and area of copper plate, and the gap distance between copper plate and permanent magnet. As results, higher eddy current value was obtained at where the change of polarity exists in permanent magnet configuration, and the highest eddy current value was observed at the copper plate thickness of 5 mm and the area of 80 mm ${\times}$ 80 mm. From the resulted optimized conditions above, which are 7 mm gap distance between a superconductor and permanent magnets and 80 mm ${\times}$ 80 mm ${\times}$ 5 mm dimension of a copper plate, the stiffness value was 65 % increased comparing to without any copper plate insertion.

• 한국주거학회논문집
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• 제18권5호
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• pp.73-84
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• 2007

Permanent rental housing, the construction of which was strongly financed by the central government, is regarded as a social housing for those who fall within the lowest income bracket. Differing from "public rental housing", offered to tenants for sale after a five year rental period, this type of housing is intended for rental use on a long-tenn basis. At present, about 190,000 permanent rental housing units exist in Korea. According to a statistics, 15.6% of its residents did not pay their management fee and rental payment in 4 or more months in 2005, which places stress on the housing management. Based on the "eviction condition" stipulated in the tenancy agreement for permanent rental housing, a householder owning assets or a vehicle which is not used as his means of living, who is overdue with his management fee and rental payment for a long time, may be evicted from the house. However, there are many conflicts and problems between administrators/housing managers and residents in the process of enforcing this regulation. The purpose of this study is to explore the key issues associated with the present situation and the reasons why so many management fee and rental payment for permanent rental housing are overdue. For the purpose of research, data were collected from 10,990 permanent rental housing residents nationwide via a questionnaire survey in February 2007. One third of the respondents had an experience of more than 2 months overdue since they have moved in current residence. For further analysis, the respondents were divided into three groups, based on their working ability. The major finding showed that the group of respondents who have working ability required a more practical plan, such as employment, to have a sustainable life, while the other group of no labor force indicated a need for more housing allowance from the government. To suggest more specific alternatives for the subject of housing payment overdue, further comparison study should be performed between the residents of permanent rental housing and other low income tenants in private housing sector.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권2호
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• pp.146-153
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• 2005

In a permanent magnet brushless dc motor, cogging torque is produced by the magnetic attraction between the rotor mounted permanent magnets and the stator teeth. This always produces a pulsating torque ripple resulting in vibration and acoustic noise, which is detrimental to the motor performance. This paper deals with the analytical prediction of cogging torque and the various cogging torque minimization techniques as applied to a permanent magnet brushless dc motor.

• 한국건축시공학회지
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• 제4권4호
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• pp.135-142
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• 2004

The purpose of this study is to predict remodeling timing of Permanent Rental Housing through historic data and cash flow analysis. For this aim, the study has estimated cash flow of Permanent Rental Housing considering initial construction costs, government supporting fund, rental incomes and maintenance expenses. Based on the expected cash flow analysis, reasonable remodeling timing is predicted for Permanent Rental Housing. The results of this study are as follows: (1) it is analyzed that building a8e of about 27 years is the best time for remodeling because cumulative surplus amounts reach maximum level, (2) it is required that remodeling should be made before 34 years of age roughly because cumulative surplus amounts change into minus from this time.

• 대한치과의사협회지
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• 제11권12호
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• pp.787-799
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• 1973

Surveying the calcification degree of permanent tooth crown in 719 Korean children (Male 387, female 332) from 2 to 10 years old by orthopantomograph, the author got the following results. 1. Female was earlier than male in calcification of permanent teeth. 2. The results of the complete calcification of the permanent tooth crown were as follows. 3. The completion of calcification in the mandibular crown was seen earlier than that of the maxilla. 4. The order of calcification in permanent tooth crowns was as follows : 1 st molar, central incisor, lateral incisor, canine, 1st premolar, 2nd premolar, and 2nd molar. 5. The completion of calcification of the permanent crowns in Korean children was slightly retarded comparing with the Japanese and the American children.

• 전기학회논문지
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• 제63권4호
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• pp.469-475
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• 2014

This paper deals with the characteristics evaluations of PM magnetization using stator coil in a Post-Assembly Line Start Permanent Magnet Motor (LSPMM) using a coupled Finite Element Method (FEM) and Preisach modeling, which is presented to analyze the magnetic characteristics of permanent magnets. The focus of this paper is the characteristics analysis relative to magnetizing direction and quantity of permanent magnets due to the eddy current occurring in the rotor bar during magnetization of Nd-Fe-B.

• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1693-1699
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• 2016

The oscillation character of permanent magnetic motor is highly related to its slot-pole match. By calculating air-gap magnet field and radial electromagnetic force of 6-phase fractional-slot concentrated-winding permanent magnetic motor with slot-pole match of 48/44, 48/46, 48/50 and 48/52 under no load and load status, oscillation character of permanent magnetic motor is analyzed. A 20kW prototype with 48 slots and 44 poles is designed. With many sensors attaching to the corresponding parts, oscillatory acceleration is measured, and spectrum of oscillation frequency is recorded as well. The experiment results give proof to the analysis method for permanent magnetic motor oscillation in this paper.