• 조명전기설비학회논문지
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• 제28권4호
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• pp.49-55
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• 2014

In this paper, we propose the cogging toque reduction technique of the dual stator radial flux permanent magnet generator. The cogging toque is caused by the torque ripple increase and vibration and noise of the generator. And it is important factor determining cut-in speed of the small wind generator. To reduce cogging torque, permanent magnet displacement was studied. And the theory of the permanent magnet displacement was formulated and the cogging torque reduction according to the permanent magnet displacement was confirmed through the finite element method.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권2호
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• pp.53-59
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• 2005

In this paper, optimum shape design of permanent magnet in slotted type Permanent Magnet Linear Synchronous Motor(PMLSM) is progressed for minimization of detent force owing to structure of slot-teeth and thrust ripple by harmonic magnetic flux of permanent magnet. In order to reduce remodeling time as changing design parameter for Permanent Magnet shape optimization, the moving model node technique was applied. The characteristics of thrust and detent force computed by finite element analysis are acquired equal effect both skewed basic model and optimum model which is optimization of permanent magnet shape. In addition to, thrust per unit volume is improved 4.l2[%] in optimum model.

• 한국패션뷰티학회지
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• 제1권1호
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• pp.133-142
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• 2003

As you see, there's no difference of the hair's before and after Magic straight permanent on the example A's hair's thickness, the rate of the tense and the C's rate of the tense, but we can find that there are a lot of difference of the A's strength of the hair, the B's hair's thickness, the strength of the hair, the rate of the tense, the C's hair's thickness, and the strength of the hair on the before and after the Magic straight permanent. That is to say, there are more damage on the condition of normal hair than the one after the Magic straight permanent. On the change of the hair's physical character, before the permanent, the hair's schedule was regular and had the healthy head skin of clear mutual boundary But after the Magic straight permanent wave, the hair's schedule changed to unregural, had unclear mutual boundary of the head skin and the schedule was taken off so the cortex showed up and so on, every condition of the damage was very heavy. On the effect of the treatment, even though it gaves the worth condition of the hair, after the Magic straight permanent formally the change of the hair gives the beautiful straight.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제12B권1호
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• pp.1-6
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• 2002

The severe problem in improving the positioning precision of a permanent magnet linear synchronous motor (PMLSM) is the large detent farce caused by the permanent magnet arrangement. It is generally an undesired effect that contributes to the torque ripple, vibration and noise of machine. The detent force is arisen from the difference of the position of a permanent magnet end and a tooth position. In this paper, the four methods to reduce detent force were studied and analyzed. The methods are adjusting the width of permanent magnet, varying the shape of armature teeth, relocating the permanent magnet, and adjusting the width of permanent magnet and relocating the permanent magnet at the same time. To analyze the detent farce according to flour methods, a two-dimensional Finite Element Analysis [FEA] was used and we compared with the ratio of reduction of the detent farce according to the flour methods.

• 패션비즈니스
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• 제12권2호
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• pp.1-11
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• 2008

The purpose of this study is to explore to determine the maximum volume with doing permanent waving in flat crown of the head. The method was like this. First of all, the diameter, the ratio of the circumference of a circle to its diameter and the number of rotations were analyzed same hair using permanent waving rods each number of 1$\sim$10. Secondly, the increasing rate of volume of curls number of 1$\sim$10 was analyzed. According to the result of the experiment, as the number of permanent waving rods were bigger, the ratio of the circumference of a circle to its diameter constant was increasing but the number of rotations was decreased. When the permanent waving rods of each number 1-3(Big diameter) were used, the volume was decreased. That's because there was fewer rotation compared to the diameter and was no ample combed dried hair. Due to this kind of reason, there was no perfect curling. Once number 10 permanent waving rods (most small size) was used, the shape of curling was strong and the stability was made after combed dried hair. But volume was decreased by 9% because of the cohesive power. In case of number of 4$\sim$9 rods used, volume was increased. Volume was highest when permanent waving rods was number 5 which was used combing on base both morphology and numerical value.

• 치과방사선
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• 제15권1호
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• pp.67-74
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• 1985

The incidence and associated dental abnormalities of taurodontism were studied radiographically (panoramic view) in 1895 patients of deciduous dentition and 2167 patients of permanent dentition who had visited to the Department of Oral Radiology, Kyung Hee University in Korea. The obtained results were as follows: 1. The prevalence of taurodontism was 3.59% in the deciduous dentition group, and 1.8% in the permanent dentition group. 2. There was no definite sex difference in the deciduous dentition, and the permanent dentition group. The type of mesotaurodontism was predominent in the deciduous dentition group, and hypotaurodontism in the permanent dentition group. 4. The vast majority of this abnormalities had occurred in the mandibular 1st deciduous molar in the deciduous dentition group, and mandibular 2nd permanent molar in the permanent dentition group. 5. Of the cases with taurodontism, the deciduous dentition group revealed 95.6% bilaterally, and 82% bilaterally in the permanent dentition group. 6. Multiple teeth occurance, not single tooth only, were involved in 98.5% of the cases in the deciduous dentition group, and 82% in the permanent dentition group.

• 한국의류산업학회지
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• 제24권6호
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• pp.775-781
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• 2022

As part of research to develop a permanent wave-reducing agent for hair, in the current study, 0.1%-1.0% of Polyquaternium-10 was added to a permanent reagent containing Nicotinoyl Dipeptide-23 to prepare the agent, which was tested on damaged hair. The pH change was relatively stable even after a date, but due to the hair's natural composition, 0.1%-0.6% of the Polyquaternium-10 concentration according to pH was suitable. The temperature safety experiment demonstrated it to be stable at a high temperature and at room temperature, but when a Polyquaternium-10 concentration of 0.9% or higher was added at 0℃, coagulation occurred. In terms of the force efficiency of permanent wave formation, wave efficiency lowered as the concentration increased: the longer the wave lasts, the lower the Polyquaternium-10 concentration. The permanent moisture content was found to be higher as the concentration of Polyquaternium-10 increased. Therefore, when Polyquaternium-10 is applied to the permanent wave-reducing agent, considering stability, permanent formation, durability, and moisture rate, the most suitable concentration was found to be that of Polyquaternium-10 in the cysteine-reducing agent. A novel finding from this study is that as the concentration of Polyquaternium-10 increases, the consistency of the permanent wave-reducing agent changes, shifting from a liquid to a viscous liquid formulation.

• 대한치과교정학회지
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• 제15권2호
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• pp.341-352
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• 1985

The primary objective of this study is to estimate of the mesiodistal crown diameters of the unerupted permanent successors derived from the mesiodistal crown diameters of the deciduous teeth in Korean population. The subjects were 54 individuals (twenty nine boys and twenty five girls) with normal occlusion aged 6 to 13 years. The mesiodistal crown diameters of the deciduous and the successional permanent teeth were measured from the longitudinal dental cast models using the sliding calipers (Mitutoyo Co.). From the study, the results are as follows; 1. Sex differences of mesiodistal won diameters were less in the deciduous teeth, but male were more than that of female in the successional permanent teeth. 2. The mesiodistal crown diameters of the deciduous central incisors, lateral incisors, canines were smaller than that of the successional permanent teeth and the deciduous 1st molars, and 2nd molars were more larger than that of the successional permanent teeth. 3. Size differences between sum of the mesiodistal crown diameters of central incisors and lateral incisors in the decidous teeth and the successional permanent teeth were $7.20{\pm}1.79mm$ in upper, $5.38{\pm}1.64mm$ in lower and that of canine,1st molar and 2nd molar in the deciduous teeth and the successional permanent teeth were $0.56{\pm}1.19mm$ in upper, $2.22{\pm}1.19mm$ in lower. 4. In male, the correlation coefficients between the upper deciduous central incisor and the successional permanent tooth (r = 0.57) and in female, the correlation coefficients between the upper deciduous 1st molar and the successional permanent tooth (r=0.67) appeared the highest. 5. The regression constants were determined to estimate the mesiodistal crown diameters of the unerupted successional permanent teeth.

• 한국인터넷방송통신학회논문지
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• 제21권3호
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• pp.137-142
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• 2021

최근에는 회전자에 희토류 영구자석을 삽입하여 높은 효율과 출력밀도를 얻을 수 있는 매입형 영구자석 (IPM: Interior Permanent Magnet) 전동기 또는 표면부착형 영구자석 (SPM : Surface Permanent Magnet) 전동기처럼 영구자석이 사용된 전동기의 연구가 활발히 이루어지고 있다. 영구자석을 사용하기 때문에 릴럭턴스 전동기나 유도전동기와 비교해 효율이 높고 출력밀도가 높은 장점이 있으나 회전자에 영구자석을 삽입함으로써 고속운전 및 영구자석의 감자로 인한 신뢰성 감소, 희토류 금속의 원가 상승 등이 문제시되고 있다. 본 논문에서는 희토류 영구자석 전동기를 대체할 수 있는 미래기술 개발과, 희토류 저감형 전동기와 탈 희토류 전동기의 기술 선점을 요구하는 시대적 이슈(Issue)에 맞춰 영구자석이 필요 없는 스위치드 릴럭턴스 전동기 (Switched Reluvtance Motor, SRM)를 구동시키기 위한 구동 제어에 연구하고자 한다. PSIM 시뮬레이션 프로그램에서 제공하는 3상 SRM library를 이용하여 회전자 위치 정보 센서를 이용한 SRM의 구동 및 제어 시스템 모델링 (Modeling)을 연구하고자 한다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.179.2-179.2
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• 2010

This research has been performed to provide fundamental design aspects of Permanent Magnet Synchronous Generators(PMSGs) for a kilowatt class wind turbine. When it comes to kilowatt class wind turbines, the typical type of generators are Axial Flux Permanent Magnet(AFPM) generators. However, Radial Flux Permanent Magnet(RFPM) generators have been optimally designed to study the output characteristics of a kilowatt class wind turbine in Graduate School of Wind Energy, POSTECH. An existing squirrel-cage rotor has been modified for another newly designed permanent magnet rotor to utilize the commercially existing stator rotor. Electromagnetic analysis utilizing Finite Element Methods tools(ANSYS, MAXWELL 2D) has been applied to analyze the system.