• 한국운동역학회지
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• 제28권3호
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• pp.165-173
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• 2018

Objective: The purpose of this study is to provide biomechanical basis data for the analysis of the maximum vertical ground reaction force, the maximum plantar pressure, the average plantar pressure, and the contact area according to the type of the insole through the insole insertion type foot pressure gauge. Method: In the treadmill, the slope was set at 10%, the first type A was worn at a walking speed of 3.5 km / h, and then walking was carried out using B, C, and D types. Data from 20 boots with consistent walking were extracted and plantar pressure data were collected and analyzed. Results: Functional insole was more effective than conventional insole for maximum vertical ground reaction force, maximum plantar pressure, average plantar pressure, and contact area at 10% of treadmill ramps. Conclusion: In this study, D-type insole supports the cushion in the middle part and supports the heel cup with hardness in the hind part, so that it is the most effective insole by lowering the plantar pressure and dispersing it more widely.

• 설비공학논문집
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• 제20권7호
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• pp.447-454
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• 2008

The regenerative evaporative cooler(REC) is to cool a stream of air using evaporative cooling effect without an increase in the humidity ratio. In the regenerative evaporative cooler, the air can be cooled down to a temperature lower than its inlet wet-bulb temperature. Besides the cooling performance, for practical application of the regenerative evaporative cooler, the compactness of the system is also a very important factor to be considered. In this respect, three different configurations, i.e., the flat plate type, the corrugated plate type, and the finned channel type are investigated and compared for the most compact configuration. The optimal structure of each configuration is obtained individually to minimize the volume for a given effectiveness within a limit of the pressure drop. Comparing the three optimal structures, the finned channel type is found to give the most compact structure among the considered configurations. The volume of the regenerative cooler can be reduced to 1/8 by adopting the finned channel type as compared to that of the flat plate type.

• 품질경영학회지
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• 제43권3호
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• pp.299-312
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• 2015

Purpose: This paper analyzes the phenomenon on the degradation of the electrical performance by the pressure in the manufacturing process of sandwich type radomes. Methods: This paper consists of two steps to analyze the relation between the electrical performance and the pressure. First, the thickness of the core of the flat panels which were fabricated with different pressure was measured with the microscope, and then the electrical performance of the flat panels was analyzed with simulation and experiment. Based on the results of the electrical performance and the measured thickness with respect to the flat panels, the relation between the electrical performance and the applied pressure in the manufacturing process was analyzed. Results: The simulated and measured results with respect to the flat panel shows that the high pressure results in the nonuniform thickness of the core, which is applied to the radome fabrication. As a result, the degradation of the electrical performance occurs because the unintended scattered field is generated as the electromagnetic wave transmits (or impinges upon) the radome. Furthermore, we observed that the electrical performance of both the flat panel and the radome got worse as the high pressure was applied. Conclusion: Through simulation and experiment, therefore, it is demonstrated that for the high pressure in the manufacturing process the nonuniform thickness of the core increases and results in the degradation of the electrical performance of the radome.

• 한국습지학회지
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• 제7권2호
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• pp.53-67
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• 2005

천수만은 전형적인 반 폐쇄형만으로 수로, 사퇴, 작은 섬 그리고 갯벌 등 다양한 환경들이 있다. 1983년에서 1985년 사이에 건설된 서산 A와 B 방조제는 천수만 북부의 퇴적환경을 지속적으로 변화시켰을 것으로 보인다. 황도 갯벌과 주변 해역의 퇴적환경을 파악하기 위하여 2003년 6월과 10월에 표층과 주상 퇴적물을 채취하였다. 표층 퇴적물은 5개의 퇴적상으로 구성되어 있었다. 일반적으로 10월의 표층퇴적물은 6월과 비교하여 갯벌은 조립해 졌으나 주변 해역은 거의 변화가 없었다. 3개의 주상퇴적물의 퇴적상은 황도 주변 갯벌은 파랑과 조류 에너지가 상대적으로 높고, 조수로 근처의 갯벌은 에너지가 상대적으로 낮은 것으로 나타났다. 황도 갯벌의 11개월 동안 단기 퇴적률은 중앙지역은 퇴적 되었으나, 갯벌의 동쪽 측면과 서쪽 측면은 침식된 것으로 나타났다. 이는 방조제에 의하여 조류 형태와 퇴적물 순환이 변화되었기 때문으로 보인다.

• 한국운동역학회지
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• 제26권2호
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• pp.237-242
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• 2016

Objective: The purpose of this study was to compare the joint movements and muscle activities of novices according to pedal type (flat, clip, and cleat pedal). Method: Nine novice male subjects (age: $24.4{\pm}1.9years$, height: $1.77{\pm}0.05m$, weight: $72.4{\pm}7.6kg$, shoe size: $267.20{\pm}7.50mm$) participated in 3-minute, 60-rpm cycle pedaling tests with the same load and cadence. Each of the subject's saddle height was determined by the $155^{\circ}$ knee flexion angle when the pedal crank was at the 6 o'clock position ($25^{\circ}$ knee angle method). The muscle activities of the vastus lateralis, tibialis anterior, biceps femoris, and gastrocnemius medialis were compared by using electromyography during 4 pedaling phases (phase 1: $330{\sim}30^{\circ}$, phase 2: $30{\sim}150^{\circ}$, phase 3: $150{\sim}210^{\circ}$, and phase 4: $210{\sim}330^{\circ}$). Results: The knee joint movement (range of motion) and maximum dorsiflexion angle of the ankle joint with the flat pedal were larger than those of the clip and cleat pedals. The maximum plantarflexion timing with the flat and clip pedals was faster than that of the flat pedal. Electromyography revealed that the vastus lateralis muscle activity with the flat pedal was greater than that with the clip and cleat pedals. Conclusion: With the clip and cleat pedals, the joint movements were limited but the muscle activities were more effective than that with the flat pedal. The novice cannot benefit from the clip and cleat pedals regardless of their pull-up pedaling advantage. Therefore, the novice should perform the skilled pulling-up pedaling exercise in order to benefit from the clip and cleat pedals in terms of pedaling performance.

• 대한기계학회논문집A
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• 제28권9호
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• pp.1352-1358
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• 2004

The mechanical spring is one of widely used machine elements. Among various kinds, flat-type spring loaded by a rotating pin was studied. A flat spring was simplified to a cantilever beam, and numerical analysis was attempted. Since the loading pin rotates about a separate axis from the fixed spring or vice versa, the location, direction, and magnitude of the contact force including normal contact and friction loads vary accordingly. Meanwhile, the spring is deformed substantially as the relative motion progresses. Therefore, this problem needs to be formulated taking the follower loading characteristics and geometrical non-linearity into account. Derived nonlinear differential equation was solved to yield the spring deflection, contact force and the torque to rotate the pin, and the result was compared with a finite element solution. Also, the influences of principal design parameters were studied. The proposed methodology is expected to be useful for the design of pin-loaded flat spring and the prevention of mechanical failures in the form of yielding or fatigue failure of spring or severe wear of the components.

• 한국콘텐츠학회논문지
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• 제18권1호
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• pp.441-451
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• 2018

이번 논문의 주요 관점은 코리올리힘(Corioli's force)의 원리와 손끝의 감각을 이용하여 고속회전(RPM)에 의해서 기벽 표면에 흠집을 내어 스트라이프(Stripe)의 질감(texture)을 안쪽에서 외벽으로 밀어 늘리는 방식과 코리올리힘(원심력)의 다변화된 아름답고 다이나믹한 독특한 외벽 질감 표현이 관건인데 이를 코리올리힘 기법이라고 정하였다. 또한 전통적인 옹기(onggi)의 평저굽(Flat Bottom Foot)성형 방식을 전기물레를 이용하여 빠른 회전력으로 원통 안쪽에서 밖으로 밀어 외벽을 늘림과 동시에 바닥의 밑면을 평평하게 굽을 펴는 새로운 방식의 평저굽을 개발하였는데 이러한 기법들을 융합하여 새롭고 현대적이면서 독특한 인테리어 작품을 만드는 것이 목적이다.

• Steel and Composite Structures
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• 제31권4호
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• pp.329-340
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• 2019

An innovated type of the flat steel plate-lightweight aggregate concrete hollow composite slab was presented in this paper. This kind of the slab is composed of flat steel plate and the lightweight aggregate concrete slab, which were interfaced with a set of perfobond shear connectors (PBL shear connectors) with circular hollow structural sections (CHSS) and the shear stud connectors. Five specimens were tested under static monotonic loading. In the test, the influence of shear span/height ratios and arrangements of CHSS on bending capacity and flexural rigidity of the composite slabs were investigated. Based on the test results, the crack patterns, failure modes, the bending moment-curvature curves as well as the strains of the flat steel plate and the concrete were focused and analyzed. The test results showed that the flat steel plate was fully connected to the lightweight aggregate concrete slab and no obvious slippage was observed between the steel plate and the concrete, and the composite slabs performed well in terms of bending capacity, flexural rigidity and ductility. It was further shown that all of the specimens failed in bending failure mode regardless of the shear span/height ratios and the arrangement of CHSS. Moreover, the plane-section assumption was proved to be valid, and the calculated formulas for predicting the bending capacity and the flexural rigidity of the composite slabs were proposed on the basis of the experimental results.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.1164-1167
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• 2003

Recently CRT is getting flatted, As change of CRT trend from normal type to Flat type, the material of Shadow Mask was also changed from AK(Aluminum Killed) to Invar(Fe-Ni alloy) materials Until now we have used just AK(Aluminum Killed) for normal type TV(not flat type), but main raw material of shadow mask component was changed. . However recently Invar(Fe-Ni alloy) materials, which has advantage of Low Thermal Expansion and High Strength, has been developed as well as applying in mass production as CRT's trend has become more flat and fine pitch. As main raw material of shadow mask component was changed, conditions of process were changed. One of them, the importance of pre-etching process (assistant process for developing & etching) is improved because there are so many particles in the pre-etching bath because of Ni compounds. Since the solubility of Ni in pre-etching solvent is very low related to Fe's, so the compounds of Ni happen to make particles.(the solubility of Fe is twenty times Ni's) that particles happen to make process troubles and NG productions so to clear the particles we had to established high cost filtering system, but it is useless. As time goes by the quantity of particles (Ni compounds) was increased because of the capability of filtering system was not enough, the particles was produced continuous in bath, and it make quality problems. Hence we tried to develop the new pre-etching solution to remove the particles (Ni compounds) and to cost down the filtering system's running cost. But in improving the solution we discovered the new pre-etching solution made the PR developing better. In former solution there were three kinds of chemistry (COOH)2 , H2O2 , H2S04 .first the function of (COOH)2 is drilling the surface of Invar, during this mechanism Ni compounds occurred. Second the function of H202 is removing the PR fringe (half UV exposure zone on PR(PVA)), Third the function of H2S04 is the catalysis of (COOH)2 In those, (COOH)2 was the main reason to make the Ni compounds. So to improve the solutions we had to change (COOH)2 to the other material. the chemistry we improved was a complex chemistry based on H2S04 . after using this chemistry the particles problem was disappeared and there was another advantage cut down the PR fringe. The New solution made the function of H202 better so the PR developing improved. To be direct the catalyst of the new solution helped the H202. anyway First thing after change the solution the quality of shadow Mask for flat color TV was improved & the yield also improved. But the more important thing is how to control the new solution. So we accepted the new concept which was the degree of freshness. The degree of freshness is based on non-reacted solution which was 100% ( the degree of freshness) and calculated the melted Ni quantity as time goes by. So we made the gauging liner plot. In conclusion, many companies tried to make fine pitched Shadow Mask ,generally to make quality jump up it needed a lot of cost & persons .in this case the shift of core material made it possible.

• 한국자동차공학회논문집
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• 제19권1호
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• pp.101-108
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• 2011

Understanding the exhaust gas recirculation (EGR) cooler fouling in diesel engine is important factor in the durability characteristic of a EGR system. We develope a test rig and PM feeder using carbon black to examine the effect of fouling on EGR cooler devices those were consisted of flat and shell & tube type. The EGR cooler fouling process is a complex interaction involving heat exchanger shape, boundary condition, constitutes, chemistry and operating mode. As the soot deposited to EGR cooler, these formed a thin deposit layer that was less heat exchange than the fresh status of tube enclosing the exhaust gas, resulting in lower heat exchange effectiveness in both type coolers. But these deposits caused different results in pressure drop, it is increased in flat type, but decreased in Shell & tube type of EGR cooler. A cause was estimated from a change of the flow structure and a decrease of contact area as the EGR cooler fouling.