• 대한소아치과학회지
• /
• 제10권1호
• /
• pp.77-83
• /
• 1983

The purpose of this study was to observe the microleakage of a pit and fissure sealant at the tooth-restoration interface. One hundred and sixty-seven extracted permanent and deciduous teeth were used and some simple mechanical pretreatment were done before etching. The degree of microleakage was assessed by $Ca^{45}$ after 24 hours, and 2 months. The results were as follows: 1. Among total 167 teeth, 53 teeth (32%) were demonstrated the microleakage. 2. After 2 months the leakage was increased from 22 percent to 35 percent in permanent teeth, and from 32 percent to 43 percent in primary teeth. 3. The group treated by fluoride paste was demonstrated the largest leakage, 50 percent in primary teeth and 33 percent in permanent teeth. There are more leakage in primary teeth (38%) than permanent teeth (28%).

• 제어로봇시스템학회논문지
• /
• 제9권2호
• /
• pp.140-144
• /
• 2003

A navigation sensor system for outdoor AGV(Automatic Guided Vehicle) using AMR(Anisotropic Magnetoresitive) sensors is described. We derive a formula of the position of AMR sensor using the measured magnetic field intensity due to permanent magnet with constant distance. The system consists of sensor board. sensor control board and position processing board. The sensor board measures magnetic field intensity, the sensor control board controls the measurement of six sensors sequentially, and the position processing board computes the accurate position of the permanent magnet using Least Square Method. We arranged six sensors at intervals of 30cm and measured the position of the permanent magnet moving at intervals of 30cm. Experimental results showed that we can get standard deviation of 2mm and error of &\pm&4.5mm at a height of 20cm from the permanent magnet.

• 전기학회논문지
• /
• 제60권8호
• /
• pp.1502-1509
• /
• 2011

This Paper presents characteristic analysis in terms of interior permanent magnet synchronous motor for electric vehicle propulsion using numerical analysis. Torque ripple analysis, thermal analysis, demagnetization analysis of permanent magnet and mechanical stress analysis with variable operating condition are presented. According to these characteristic analysis, both the performance of motor and possible problems during the operation are examined thoroughly in advance.

• 전기학회논문지
• /
• 제56권3호
• /
• pp.506-513
• /
• 2007

This paper proposes a rotary magnetic position sensor which has a sinusoidally magnetized permanent magnet with a small number of poles. To make the sinusoidal magnetic flux density distribution from the permanent magnet, a magnetizing future is optimized by the DOE(Design of Experiments) method. The magnetization process is analyzed using the Preisach model and 2 dimensional finite element method. The magnetic flux density distribution from the magnetized permanent magnet is very similar to ideal sine wave. The simulation result of the magnetic flux density distribution is compared with the experimental one. Also the availability of the proposed rotary type magnetic position sensor is confirmed by position calculation technique.

• 전기학회논문지
• /
• 제67권2호
• /
• pp.337-342
• /
• 2018

Spent fuel is moved from the reactor into the spent fuel pool when nuclear power plant permanently shutdown. The sole function of a permanently defueled facility is to store spent fuel in a quiescent state. The function of electric system and loads are reduced. It is necessary to establish an operating strategy of electric system in the permanent shutdown nuclear plant. This paper reviews required loads and design criteria considering transition to permanent shutdown. An operating strategy of onsite electric system is proposed considering decommissioning strategy and stage of defueled condition.

• 조명전기설비학회논문지
• /
• 제26권11호
• /
• pp.109-115
• /
• 2012

Recently, permanent magnet synchronous motor are applied to various applications. Because of the importance of high reliable operation in these areas, many research related to the fault detection and diagnosis of inverter system are conducted. So, a faults model for an inverter-driven permanent magnet synchronous motor is studied by using the fault current of motor according to switch open, which can be effectively used for performance evaluation of the diagnostic algorithm. And fault of the permanent magnet synchronous motor inverter drive system is divided into four types. The feasibility of the proposed method are improved by simulation and experiment.

• 한국주거학회논문집
• /
• 제14권3호
• /
• pp.93-100
• /
• 2003

Considering the present development situation of public rental apartment since 1982, the supply of homeless housing for low-income dwellers has contributed a amount of quantities, but has been deficient qualities in housing policy. To reflect the architect the properties of dwellers in rental apartment, this study is aimed at investigating the residential character and the consciousness of housing movement through questionaries in permanent rental apartment and fifty years period rental apartment complexes. The results of this study were as follows; The permanent rental apartment is dissatisfied with site location, site shape and building layout in housing environment view, the fifty years period rental apartment is dissatisfied with building area, rental bond, rental fee and maintenance cost in economics view. Housing type of movement preference hereafter is showed “rental apartment” as priority. Therefore, it is necessary to construct public rental apartment for low-income dwellers increasingly.

• 전기학회논문지
• /
• 제58권6호
• /
• pp.1105-1109
• /
• 2009

This paper deals with a polynomial thrust equation of a permanent magnet linear synchronous motor that is considered by a skew and overhang effects of permanent magnet. The skew length, the overhang length, the width and height of permanent magnet, the teeth length and air-gap length which effect to the flux density of air-gap are selected as variables of the polynomial thrust equation. Polynomial thrust equation is elicited by the 6 parameters. The results are satisfied that the values by polynomial thrust equation are compared ones by using 3-dimensional finite element analysis and experiment.

• 한국실내디자인학회:학술대회논문집
• /
• 한국실내디자인학회 2006년도 춘계학술발표대회 논문집
• /
• pp.165-168
• /
• 2006

This study beings from solving problems of permanent rental housing with environmentally-friendly planning factors to raise quality of life. Environmentally-friendly planning factors of permanent rental housing are derived from the study of references and green building certification systems of other countries. Surveys of inhabitants and experts give weights on these factors. Inhabitants do are focussed natural ventilation, life cycle cost, operation and maintenance cost. This reflects their interest in indoor amenity and a burden on the cost. Experts put more weights on pedestrian spaces considering the old and feeble persons and block planning. Besides, T-test pointed out that there are meaningful differences in land use between inhabitants and experts. Though inhabitants' opinion has priority because they are real user, experts' opinion which has the variety and the view in the long term should be reflected.

• 전기학회논문지
• /
• 제58권3호
• /
• pp.496-501
• /
• 2009

Interior Permanent Magnet Synchronous Motor (IPMSM) produces two kind of torque that Magnetic and Reluctance torque. The permanent magnet linkage flux ${\Psi}_a$ and d-axis and q-axis inductances have an important influence on the torque characteristic of IPMSM. Thus their accurate prediction is essential for predicting performance aspect such as the torque and flux-weakening capabilities. In this paper, the influence of barrier width on the ${\Psi}_a$ and $L_d$, $L_q$ is calculated by FEM analysis. Predictions are validated by comparison the average torques, using Maxwell Stress Tensor method.