• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.325-328
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• 1988

Until now to analysis of LIM first winding current distribution is assumed to be finite sinusoidal current. But this method have demerits to learn the difference of LIM's characteristics which is produced by difference of winding method. So in this paper amodel of which period is the length core and air gap mmf of this winding current developed to fourier series, then mmf which contain air gap mmf is obtained this mmf is transformed to current sheet and the analysis result which are obtained by using sinusoidal first current and proposed method are compared.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1087-1088
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• 2006

In this paper, the inductive power collector using electromagnetic Induction for vehicle such as the PRT(Personal Rapid Transit) system is suggested and some ideas for power collector design to improve the power transfer performance are presented. The inductive power of secondary part is related to amount of linked flux to secondary part by the length of air-gap, which is expected by such a system parameter as mutual inductance. This paper will study for the transfer characteristic of power from input to output and equation including mutual inductance.

• 제어로봇시스템학회논문지
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• 제18권3호
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• pp.230-236
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• 2012

Shielding the air-gap magnetic field of the electrodynamic wheel below a conductive plate and opening the shielding plate partially, a thrust force and a normal force generate on the conductive plate at the open area. But, as only the variable controlling both forces is a rotating speed of the electrodynamic wheel, it is very difficult to control the forces independently by the speed. So, we discuss a novel method controlling the forces effectively through manipulating a size of the open area. The independent control is made possible by virtue of the feature that the relative ratio between both forces is irrelevant to an air-gap length and determined uniquely for a specific rotating speed of the wheel. Therefore, the rotating speed and the size of open area become new control variables. The feasibility of the method is verified experimentally. Specially, the controllable magnetic forces are used in a noncontact conveyance of the conductive plate.

• The Journal of Advanced Prosthodontics
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• 제6권1호
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• pp.39-45
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• 2014

PURPOSE. The aim of the present study was to evaluate the accuracy of three techniques for correction of cast implant bars. MATERIALS AND METHODS. Thirty cast implant bars were fabricated on a metal master model. All cast implant bars were sectioned at 5 mm from the left gold cylinder using a disk of 0.3 mm thickness, and then each group of ten specimens was corrected by gas-air torch soldering, laser welding, and additional casting technique. Three dimensional evaluation including horizontal, vertical, and twisting measurements was based on measurement and comparison of (1) gap distances of the right abutment replica-gold cylinder interface at buccal, distal, lingual side, (2) changes of bar length, and (3) axis angle changes of the right gold cylinders at the step of the post-correction measurements on the three groups with a contact and non-contact coordinate measuring machine. One-way analysis of variance (ANOVA) and paired t-test were performed at the significance level of 5%. RESULTS. Gap distances of the cast implant bars after correction procedure showed no statistically significant difference among groups. Changes in bar length between pre-casting and post-correction measurement were statistically significance among groups. Axis angle changes of the right gold cylinders were not statistically significance among groups. CONCLUSION. There was no statistical significance among three techniques in horizontal, vertical and axial errors. But, gas-air torch soldering technique showed the most consistent and accurate trend in the correction of implant bar error. However, Laser welding technique, showed a large mean and standard deviation in vertical and twisting measurement and might be technique-sensitive method.

• 터널과지하공간
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• 제27권1호
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• pp.12-25
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• 2017

국내 석회석광산은 주로 자연통기에 의존하고 있으나 자본 및 운전비용이 과다하게 소요되는 광산 전체통기방법보다 풍관과 선풍기를 이용한 국부통기방법이 바람직한 방법으로 평가된다. 국내 대단면 장대 광산갱도에 풍관이 접속된 국부선풍기를 직렬로 연결 설치하는 경우에 통기시스템의 경제성과 효율의 최적화가 반드시 요구된다. 최적화를 위한 가장 중요한 두가지의 설계변수는 벽면 이격거리와 풍관 간의 이격거리이다. 본 연구에서는 경제적 및 환경적으로 최적화된, 즉 풍관간의 이격 공간을 통한 압력손실, 누기 그리고 오염된 공기의 재유입을 최소화할 수 있는 두 설계변수 값을 도출하기 위하여 광범위한 CFD분석을 시행하였다. 기존 연구결과와 권고기준들을 고려하여 이들 변수의 연구대상 범위를 선정하였다. 본 연구의 궁극적 목표는 국내 장대 광산갱도내 설치되는 풍관 접속 선풍기의 직렬연결 국부통기시스템의 최적화를 통하여 깨끗하고 안전한 작업장 환경을 제공하기 위함이다.

• 한국컴퓨터정보학회논문지
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• 제23권7호
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• pp.63-72
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• 2018

The purpose of this study was to compare and analyze the pants pattern of the lower body of 70-85 aged women. I tried to present excellent pants pattern that is convenient and suitable for the activities of elderly women. Through this, I tried to provide basic data necessary for making elderly women 's pants. As a result of evaluating the appearance of the pants pattern according to the body type, the fit of the type 2 was evaluated as the highest in the item except the position of the front waist line. For the objective evaluation of the 3D simulation, the air gap of the pants by the body part analysis showed that there was not much difference in the air gap around the waist circumference, hip circumference, thigh circumference, and knee circumference by applying the same drawing method and body size. However, in type 2, the air gap of thigh and knee circumference parts was larger than that of type 1 and type 3. Because type 2's legs were thin but it used same size of hemline. It was thought that it is necessary to adjust the space of front and back crotch length to 1 inch (2.54 cm) instead of 1.9 cm (3/4 inch) so that the waistline position of all three types can be set up a little to cover the abdomen. This study was conducted to investigate changes in body shape of elderly women and to develop appropriate pants patterns.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.647-648
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• 2006

In this paper, magnetic levitation characteristics of hybrid magnets are experimentally shown under the newly proposed airgap condition. The digital PID controller is utilized to control the airgap of the magnetic levitation system.

• Journal of Power Electronics
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• 제19권2호
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• pp.344-352
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• 2019

To achieve high efficiency and reliability, multiphase interleaved converters with coupled inductors have been widely applied. In this paper, a coupled inductor design method for 2-phase interleaved boost converters is presented. A new area product equation is derived to select the proper core size. The wire size, number of turns and air gap length are also determined by using the proposed coupled inductor design method. Finally, the validity of the proposed coupled inductor design method is confirmed by simulation and experimental results obtained from a design example.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.245-251
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• 2001

A fretting wear tester is developed for experimental study on the fuel fretting problem of light water reactor. The feature of the developed tester is it can simulate the existence of gap between spring and fuel rod as well as different contacting force including the just-contact condition (0 N on the contact). Used are a servo-motor, an eccentric cylinder and lever mechanism for driving system. A spacer grid cell is constituted with four strap segments (each segment has a spring). This fretting wear tester can also be used as a fatigue tester of a spacer grid spring with the frequency of more than 10 Hz. It is required to simulate the frequency of the vibrating fuel rod due to flow-induced vibration in a reactor. In fretting wear test, up to two span-length of a fuel cladding tube can be accommodated. A specimen of cladding tube of one span-length is specially designed, which can be extended for two-span test. For .fatigue test, a device for clamping the spring fixture is installed additionally, Presently, the tester is designed for the condition of air environment and room temperature. The variation of the reciprocal distance is measured to check the stability of input force, which will be exerted to the cladding (for fretting wear. test) and the spring (for fatigue test) specimen.

• 한국수소및신에너지학회논문집
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• 제23권2호
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• pp.183-190
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• 2012

The research shows the experiment results according to the combustion characteristics and configuration of the linear generator of powerpack for the generating power applying the 2-stroke compact linear engine. The powerpack used in this paper consists of 2-stroke linear engine, linear generator and air compressor parts. For identifying the combustion characteristics and generating power of linear engine, some parameters were varied sucha as electric load, fuel input calorie, spark timing delay and equivalence ratio. Also generating power was confirmed at each operation conditions, when the air gap length of linear generator part was changed as each 1.0 mm and 2.0 mm. During the all operations, intake air was inputted under the wide open throttle. Mass flow rate of air and fuel was changed using mass flow controller, after these were premixed by premixture device, and then premixed gas was supplied directly into each cylinder. As a result, piston frequency and combustion characteristics were different at each conditions according to parameters affecting the combustion such as fuel input calorie, resistive load, spark timing delay and equivalence ratio. Consequently, these had an effect on generating power.