• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.173-181
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• 2017

In this paper, the bifurcation criteria for inductive power transfer (IPT) systems is suggested considering the inductive power pad losses. The bifurcation criteria for series-series (SS) and series-parallel (SP) topologies are derived in terms of the main parameters of the IPT system. For deriving precise criteria, power pad resistance is obtained by copper loss calculation and core loss analysis. Utilizing the suggested criteria, possibility of bifurcation occurrence can be predicted in the design process. In order to verify the proposed criteria, 50 W IPT laboratory prototype is fabricated and the feasibilities of the switching frequency and AC load resistance shift to escape from bifurcation are identified.

• 한국소음진동공학회논문집
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• 제22권12호
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• pp.1206-1212
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• 2012

The brake squeal propensity due to the friction-velocity curve is numerically investigated. The finite element models for the disc and pad are correlated with the modal test. In the friction-engaged system modeling, the friction function is linearized at the equilibrium. The damping term induced by friction-velocity slope is incorporated into the equations of motion. In the complex eigenvalue analysis, it is found that the pad shear mode is very sensitive to the friction curve. The results shows that the squeal propensity of the pad shear mode can be controlled by the design parameters such as pressure and stiffness.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.1042-1045
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• 2005

The wedge type rail clamp has the operating mechanism: First, the jaw pad clamps a rail with small clamping force. Next as the wind speed increases, the clamping force of the Jaw pad Is Increased by the wedge. The initial clamping force of a jaw pad was determined by the clamping angle of a locker. In this study, we carried out the finite element analysis to evaluate the relationship between the clamping angle of a locker and the clamping force of a jaw pad with respect to the design wind speed, such as 2, 4, 6, 8, and 10m/s, we adopted the wedge type rail clamp fur 50tons class container crane with the wedge angle of $10^{\circ}$.

• Tribology and Lubricants
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• 제33권3호
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• pp.85-91
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• 2017

This work studies the flow behaviors in the gap between the friction pad and separator in wet-clutch systems. The fluid volume of the lubricant is modeled using the entire system of wet-clutch pack of a dual clutch transmission that has larger outer radius of odd gear shifts and smaller inner radius of even gear shifts. Flow behaviors in the gap of the clutch pad are computed using the gear shift modes that consider the real relative velocities between the friction pad and separator. Flow behaviors in the gap of the disengaged clutch pad are mainly investigated for the wet-clutch system, whereas the engaged clutch pad is modeled with no fluid rate through the contacting surfaces. The developed hydrodynamic fluid pressures and velocity fields in the clutch pad gap are computed to obtain the relevant information for managing flow rates in wet-clutch packs under dual operating conditions during gear shifts. These hydrodynamic pressures and velocity fields are compared on the basis of each gear level and gap location, which is necessary to determine the effects of groove patterns on the friction pad. Shear stresses in the gap locations are also computed on the basis of the gear level for the inner and outer clutch pads. The computed results are compared and used for the design of cooling capacity against frictional heat generation in wet-clutch pack systems.

• 패션비즈니스
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• 제26권2호
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• pp.143-155
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• 2022

The purpose of this study was to develop protective clothing that could alleviate fall impacts. Fall impact protection pants for elderly women were designed, and motion adaptable hip pads and knee pads printed by 3D printing were integrated into the pants and evaluated. First, the design of the fall impact protection pants with variable motion was semi-loose fitting pants that could be worn and detached from the protective pad. A pad pocket was made in the lining inside the pants so that the protective pad could be fixed to the protective area. Second, in the evaluation of the appearance of the fall impact protection pants, the wearer group had a good score of 4.60 or higher for all questions on color, material, ease, and fit. In the evaluation of the insertion method of the protective pad, the flexibility of the pad, and the weight of the pad, the subjects' scores were 4.30~4.80. The fit of the fall impact protection pants was excellent in the texture and elasticity of the outside and inside of the pants. There was no discomfort due to the pad(4.60), and no difficulty in movement during wearing activities was reported. During squatting, it was evaluated as 4.80, indicating that the motion adaptable hip joint and knee pads were highly effective during operation.

• Tribology and Lubricants
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• 제39권6호
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• pp.268-272
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• 2023

This study explores the characteristics of tilting pad journal bearings used in the high-speed rotating shaft systems of centrifugal compressors. A centrifugal compressor is a high-speed rotating machine that is widely used to compress gases or vapors employed in various industrial applications. It transfers the centrifugal force of a fast-spinning impeller to the fluid and compresses it under high pressure. Many high-speed rotating shaft systems, which require high stability, use tilting pad journal bearings. The characteristics of these bearings can vary depending on several properties, and identifying the appropriate characteristics is essential to optimize the design on a case-to-case basis. In this study, the authors perform a time-dependent analysis of the properties of tilting pad journal bearings and the rotordynamics of the rotating shaft system using COMSOL Multiphysics software. Specifically, the authors analyze the characteristics of the tilting pad journal bearings by performing a parametric sweep using parameters such as pad clearance, maximum tilting angle, preload, number of pads, and pad pivot offset. The authors then use the results of the bearing-characteristics analysis to evaluate the vibration of the rotating shaft and verify its operation within a desirable range. The understanding gained from this study will allow us to determine the optimal properties of these bearings and the limiting operational speed using COMSOL Multiphysics software.

• 한국의상디자인학회지
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• 제16권3호
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• pp.61-73
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• 2014

Urinary Incontinence is any leakage of urine against their will. It is not a life threatening illness but it causes negative effects both socially and psychologically. Based on many previous studies, 20-40% of adult female and 30% of men in their sixties have experienced symptoms of urinary incontinence. As the number of active aged people experiencing the symptoms increases, demand for specialized product is growing. The purpose of the study is to research the types and features of male disposable products for urinary incontinence on the market and to provide the basic data for improvement and development of better product. Products from 6 brands (Tena, Depend, Carnation, Keepers, Molimed, Abrimen) with high brand awareness both in online and offline were selected and analyzed. And product evaluation was carried out by male in their sixties with light symptom of urinary incontinence. The results are as follows. There are three types of male products for urinary incontinence: panties, diaper and pad. Among the 6 brands, the subject of analysis, only Depend from Yuhan Kimberly produces male panties while others make ones for unisex. There is no diaper product only for male, and Tena, Molimed, Abrimen have pad type products for male. Male panties from Depend emphasizes their design considering male's physical characteristics. Male pad is differentiated with female one by having different designs like triangular or pocket type which is more comforting to men. As a result of product evaluation, wearable panties similar to normal underwear were highly appreciated and satisfactory. Among various shapes of pads, 25cm long pad with wide width of front and narrow back was valued to be comfortable.

• 한국조리학회지
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• 제22권2호
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• pp.206-221
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• 2016

스마트 폰 확산과 배달 앱의 이용 증가로 인해 배달 앱 이용 시 소비자가 지각하는 감정반응과 앱 이용의도에 관한 연구의 필요성을 제시하였다. 따라서 본 연구에서는 배달 앱에 대한 이용의도를 높일 수 있는 변수로 배달 앱의 서비스품질과 PAD의 2가지 감정차원, 각성과 즐거움을 제시하여 그 역할을 규명하고자 하였다. 이러한 분석결과를 토대로 배달 앱 콘텐츠 개발과 운영에 필요한 기초적인 자료를 제공하고자 하였다. 연구의 조사대상과 공간적 범위는 최근 3개월이내 배달 앱을 이용한 경험이 있는 전국의 20세 이상 남녀 내국인 거주자로 정하였으며, 조사대상자 중에서 배달의 민족, 요기요, 배달통을 통해 음식을 주문한 경험이 있는 외식소비자들을 대상으로 설문조사를 하였다. 연구결과, 배달 앱 서비스품질의 디자인과 공감성은 각성에 긍정적인 영향을 미치며, 디자인과 신뢰성은 즐거움에 긍정적 영향을 미치는 것으로 나타났다. 배달 앱 서비스품질의 정보성과 이동성은 앱 이용의도에 긍정적인 영향을 미치는 것으로 나타났다. PAD의 즐거움은 앱 이용의도에 긍정적인 영향을 미치나, 각성은 아무 영향력이 없는 것으로 나타났다. 외식소비자들이 배달 앱을 지속적으로 이용하도록 유도하기 위해서는 디자인과 신뢰성, 정보성, 이동성이 매우 중요한 요인임을 제시하였다.

• 대한전자공학회논문지SD
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• 제47권4호
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• pp.69-74
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• 2010

알루미늄 양극산화(aluminum anodization)의 선택적인 적용을 통하여 DRAM 소자를 위한 새로운 패키지 기판을 제작하였다. 에폭시 계열의 코어(core)와 구리의 적층 형태로 제작되는 일반적인 패키지 기판과는 달리 제안된 패키지 기판은 아래층 알루미늄(aluminum), 중간층 알루미나(alumina, $Al_2O_3$) 그리고 위층 구리(copper)로 구성된다. 알루미늄 기판에 양극산화 공정을 수행함으로써 두꺼운 알루미나를 얻을 수 있으며 이를 패키지 기판의 유전체로 사용할 수 있다. 알루미나층 위에 구리 패턴을 배치함으로써 새로운 2층 금속 구조의 패키지 기판을 완성하게 된다. 또한 알루미늄 양극산화를 선택적인 영역에만 적용하여 내부가 완전히 채워져 있는 비아(via) 구조를 구현할 수 있다. 패키지 설계 시에 비아 인 패드(via in pad) 구조를 적용하여 본딩 패드(bonding pad) 및 볼 패드(ball pad) 상에 비아를 배치하였다. 상기 비아 인 패드 배치 및 2층 금속 구조로 인해 패키지 기판의 배선 설계가 보다 수월해지고 설계 자유도가 향상된다. 새로운 패키지 기판의 주요 설계인자를 분석하고 최적화하기 위하여 테스트 패턴의 2차원 전자기장 시뮬레이션 및 S-파라미터 측정을 진행하였다. 이러한 설계인자를 바탕으로 모든 신호 배선은 우수한 신호 전송을 얻기 위해서 $50{\Omega}$의 특성 임피던스를 가지는 coplanar waveguide(CPW) 및 microstrip 기반의 전송선 구조로 설계되었다. 본 논문에서는 패키지 기판 구조, 설계 방식, 제작 공정 및 측정 등을 포함하여 양극산화 알루미늄 패키지 기판의 특성과 성능을 분석하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.281-286
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• 2001

Tilting pad journal bearings have been widely used in a high speed rotating machinery, such as steam turbines and gas turbines, owing to their inherent stability characteristics. However, some peculiar fatigue failure in the babbitt metal due to spragging has been continuously occurred at the leading edge of the upper pads. The spragging is defined as the pad vibration initiated on the upper unloaded pads in a tilting pad journal bearing. This paper describes both several kinds of bearing failure related with spragging and the theoretical investigation on the prevention of the spragging phenomenon using the variation of preload. Results show that positive preload(m>0.5) assures all pads remain statically loaded under all operating conditions. For the change of design parameter to prevent spragging, thermo-hydrodynamic lubrication and rotor dynamic analysis were performed to verify temperature limitation on bearing and vibration problems on rotor bearing system.