• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.1-10
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• 1993

A design method of gear tooth profile which can reduce the noise of gear is studied. The tooth profile is generated by combining involute and cycloid tooth curves in which the involute tooth profile is near the pitch point and cycloid tooth profile at the addendum and the dedendum. Considering parameters which have an influence on the reduction of gear noise and building up a design conditions for the noise reduction of gear, the lower-noise combined gear tooth profile is designed. For the check of noise reduction of the combined gear profile, two pairs of combined profile gear, two pairs of involute gear, and a pair of cycloid gear were manufactured by the NC Wire Cutting Machine, and the experiment for measuring of gear noise was carried out on each pair. The noise reduction of the combined profile gear was obtained.

• Social Workers
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• no.3 s.35
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• pp.32-35
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• 2005

사회복지공동모금회에 의하면 지난 '희망 2005 이웃사랑캠페인'에서 전년보다 개인기부나 기업기부가 각 60% 이상씩 늘어났다고 한다. 경제가 최악이라고 다들 말하지만 국민들의 따뜻한 마음은 최악이 아니였던 것이다. 이렇게 모인 금액은 우리가 흔히 말하는 불우이웃, 즉 빈곤층과 소외계층에 나누어져 지원된다. 그런데 문제는 이러한 분위기가 정부보다는 국민들에게 더 강하게 어필되고 있는 느낌이다. 우리나라 빈곤층은 1997년 경제위기 이후 급격히 늘어 1999년 정점에 이른 뒤 2000년부터는 감소추세였다. 그러나 2003년 기점으로 절대빈곤률과 상대빈곤률이 다시 높아지고 있으며, 특히 상대빈곤층은 최악의 상태였던 1999년보다 높아졌으며 중산층은 줄고 고소득층은 늘어 사회가 양극화 되고 있다. 가난의 굴레를 벗어나기가 쉽지 않다고는 하지만 그나마 사회안전망이라 할 수 있는 국민기초생활보장제도도 빈곤층에게 인간다운 아름다운 삶을 보장받게 해주지 못하고 있는 것이 사실이다. 또한, 정부의 복지정책의 근간이 되는 기본 실태조사좌도 그 신뢰성에 문제로 제기하고 있는 현 상황과 대책을 알아보고자 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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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 $10^{\circ}$.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.7
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• pp.669-674
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• 2013

To design the optimized low noise planetary gear sets, a program called pRMC(planetary run many cases) is developed. The pRMC is especially using a combination analysis method for all gear specifications and also able to analyze any type of planetary gear sets. The pRMC is composed of the 5 sections those are generate, setting, evaluate, combine and analysis. After calculating all candidate gear sets, the pRMC could show many results that represent the character of each gear set including the transmission error which is the main gear noise factor, the contact ratios, the bending stress and so on. By comparing the results objectively, user could predict and select the optimized gear set which has quiet noise level and desired durability. The planetary gear designed by pRMC could have reduced noise and vibration level from 5 to 10 dB than previous-designed one.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.2
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• pp.296-303
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• 1987

The composite gear which is composed of involute curve and circular arc has been studied. In the vicinity of pitch point, its profile is an involute curve, and in the dedenum, a circular arc. The curve in the dedendum is generated by the circular arc of the mating gear. Though the available range between minimum and maximum radius of circular arc can be given by existing tooth profile equation, there was no formulation which relates design parameters to the desired radius. It is attempted to get the formula for the radius of circular arc as a function of design parameters, such as unwounded angle, number of teeth, module, and pressure angle. The radius of circular arc, the chordal tooth thickness at working root circle, nominal bending stress, Hertz stress and contact ratio obtained from derived formula are compared with those of the existing design criteria. And these are compared with those of involute gear.

• Journal of the Korean Geotechnical Society
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• v.29 no.9
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• pp.81-91
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• 2013

This paper investigates the shear properties of bottom ash-crumb rubber mixture reinforced with waste fishing net. Mixtures used in this experiment were prepared at 2 different percentages of crumb rubber (2 mm~10 mm) content (i.e., 0%, 50% by weight of the dry bottom ash). In this study several series of triaxial tests were carried out on the six different specimens : unreinforced bottom ash, reinforced bottom ash with 1 or 2 layers, unreinforced mixture, reinforced mixture with 1 or 2 layers. The experimental results indicated that the shear properties of bottom ash-crumb rubber mixture were strongly influenced by reinforcing layer of waste fishing net and crumb rubber addition. It is shown that the internal friction angle of bottom ash-crumb rubber mixture decrease with addition of crumb rubber due to the compression properties of crumb rubber. However, the internal friction angle of the mixture increased with an increase in reinforcing layer due to interlocking effect and friction between mixture and waste fishing net.

• Journal of the Korean Geotechnical Society
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• v.26 no.2
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• pp.55-62
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• 2010

This paper investigates the shear properties of waste tire-bottom ash mixture with various particle size of waste tire powder. Test specimens were prepared at 5 different percentages of waste tire powder content (i.e., 0%, 25%, 50%, 75%, 100% by weight of the dry bottom ash), and with three different particle sizes of waste tire powder (i.e., 0.1 mm~2.0 mm, 0.9 mm~5 mm and 2 mm~10 mm). In this study several series of direct shear tests were carried out. The experimental results indicate that the mechanical characteristics of waste tire-bottom ash mixture are strongly influenced by the particle size as well as waste tire powder content. It is shown that the shear strength and internal friction angle of waste tire-bottom ash mixture decrease with an increase in waste tire powder content. However, the shear strength and internal friction angle of the mixture increase due to interlocking effect between waste tire powder and bottom ash as the particle size of waste tire powder increases.

• Journal of the Korean Geotechnical Society
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• v.28 no.9
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• pp.47-55
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• 2012

This paper investigates the shear properties of crumb rubber-bottom ash mixture reinforced by waste fishing net (WFN). Mixtures used in this experiment consist of crumb rubber and bottom ash (2mm~10mm) with the same weight ratio. In this study several series of direct shear tests were carried out on the five different specimens : unreinforced mixture, reinforced mixtures with 1 or 2 single-layered WFN, reinforced mixtures with 1 or 2 double-layered WFN. The experimental results indicated that the shear properties of reinforced crumb rubber-bottom ash mixture were strongly influenced by reinforcing layer of WFN. It was found that the shear strength and internal friction angle of the mixtures increased with an increase in reinforcing layer of WFN due to interlocking effect and friction between mixture and WFN.