• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.332-335
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• 1997

With the advance of precision technique, the optical system is more precise and complex and the machining method of optical element which is composed of micro-grooves is developed. Especially, the method of micro-grooving using diamond tool is used widely owing to many merit, but has problems of damage of surface roughness due to tool wear and tool fracture. This paper deals with state monitoring using AE RMS in the micro-grooving. The change of AE RMS is very small with increment of cutting velocity and depth of cut. In spite of constance magnitude of principal force in machining using diamond tool of tool wear and tool fracture, AE RMS is highly fluctuated. Because changing of cutting state has relevance to surface roughness profile, surface toughness profile is expected using AE RMS.

• 열처리공학회지
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• 제5권3호
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• pp.165-170
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• 1992

The chip controls are investigated experimentally for the purpose of estimating cutting ability of hardened steel. In this experiment, hardened STD11 steel ($HR_c$ 60) is turned with carbide tool M20 under various cutting conditions and with several tool shapes. The main results obtained are as follows : 1) Cutting conditions of cutting speed 45m/min. feed 0.09-0.13 rev. depth of cut 0.4-0.6 are recommended for the chip excluding. 2) In case that the feed becomes larger and a lead angle of cutting tool becomes smaller, the chip excluding becomes easier. 3) It is confirmed that frank wear and crator wear on the cutting tool appear severely from about 10 min. after cutting start and chip excluding get worse.

• 한국정밀공학회지
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• 제27권8호
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• pp.54-61
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• 2010

In this research KP-4, one of the plastic mold steels, was coated with the AlTiN from one layer to four layers by the PVD method in the $\Phi$ cemented carbide ball end mill. Coated KP-4 was processed with various conditions. For example, slope of $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ the spindle rotation speed was changed from 10,000rpm to 16,000rpm, the tool feeding speed was changed from 1,300mm/min to 1,700mm/min, the depth of cut was also changed from 0.3mm to 0.9mm, and etc. Cutting component force according to the coating layer number, surface roughness, and the wear of tool were studied.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1995년도 춘계학술대회 논문집
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• pp.17-23
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• 1995

This paper describes investigation of the dressing time by laser in the surface grinding operation. Always dressing work is done before grinding operation. And then generates wear and roading on the wheel by contact between the grinding performance but also ground surfaces. On these states dressing work is needed. On this paper contour of the wheel by He-Ne laser is measured. It has also been found that the wheel deflection reduces the actual depth of cut and the roughness of the ground surface.

• Advances in materials Research
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• 제7권2호
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• pp.137-148
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• 2018

The present paper is a contribution in characterising end milling process of AISI 52100 ball bearing steel through statistical analyses of variance (ANOVA). The latter has been performed to identify the effect of the cutting parameters on the machined surface roughness and the cutting tool life. Wear measurements have been carried on multilayer coated carbide inserts and the respective surface roughness has been recorded. Taguchi's technique has been adapted to conduct the design experiments in terms of orthogonal arrays according to the cutting parameters (cutting speed, feed rate and depth of cut), the type of coating (TiN, TiCN, TiAlN) and lubricating condition. Regression analyses have conducted to the development of simplified empirical models that can be effectively used to predict surface roughness and tool wear in the present milling process.

• 한국정밀공학회지
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• 제11권5호
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• pp.153-160
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• 1994

In this study, residual stress and surface roughness were investigated experimentally to evaluate surface integrity on surface layer machined by CBN, ceramics and WC cutting tools. When machining difficult-to-cut material (hardened STD11 steel $H_{R}$C 60), residual stresses remaining in machined surface layer were mainly compressive. The increase of flank wear caused a shift of the compressive residual stress maximum to greater workpiece depths, but the changes did not penetrate the workpiece beneath a depth of 300 .mu. m. Surface roughness was influenced considerably by variations of the cutting speed and feed. In machining hard material, CBN and A1$_{2}$ $O_{3}$ ceramics cutting tool materials proved significantly superior to mixed ceramics A1$_{2}$ $O_{3}$-TiC and WC in evaluation of surface integrity.y.

• 한국정밀공학회지
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• 제10권3호
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• pp.69-80
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• 1993

It is important to prevent roll failure in hot rolling process for reducing maintenance coat and production loss. Roll material and rolling conditions such as the roll force and torque have been intensively investigated to overcome the roll failures. In this study, a computer roll life prediction system under working condition is developed and evaluated on IBM-PC level. The system is composed and fatigue estimation models which are stress analysis, crack propagation, wear and fatigue estimation. Roll damage can be predicted by calculating the stress anplification, crack depth propagation and fatigue level in the roll using this computer model. The developed system is applied to a work roll in actual hot rolling process for reliability evaluation. Roll failures can be diagnosed and the propriety of current working condition can be determined through roll life prediction simulation.

• 감성과학
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• 제20권3호
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• pp.97-108
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• 2017

본 연구의 목적은 스마트 피트니스웨어가 갖추어야 할 요건과 스마트 피트니스웨어의 수용 정도 및 기능 수요를 고찰하고, 이를 기반으로 퍼스널 트레이닝 효과 향상을 지원하는 피트니스용 스마트 스포츠의류의 상품기획 및 디자인 방향을 제시하는 것이다. 이를 위해 전문 피트니스 트레이너를 심층 인터뷰하고 그 응답 자료에 대해 범주분석을 실시한 결과 5개의 범주와 13개 주제어를 도출하였다. 또한 일반 소비자들을 대상으로 설문조사를 실시하여 스마트 피트니스웨어의 수용 정도와 상품개발에 필요한 기능 수요를 탐색하였다. 그 결과 전반적으로 인구통계학적 특성에 따른 차이보다는 운동의 관여도 및 운동관련 문화와 관련된 특성에 따라 스마트 피트니스웨어의 수용 정도에 차이가 있는 것을 발견할 수 있었다. 스마트 피트니스웨어에 대한 기능 수요에 대한 차이점으로는 전문 트레이너의 경우 운동 효과의 과학적 향상에 중점을 두는 반면 일반 소비자는 운동 시 지속성을 고려한 기능을 중요시 하는 것으로 분석되었다. 본 연구 결과를 종합하여 '심박 센싱, 근육 활성도 센싱, 부위별 운동 동작 각도 또는 자세 센싱, 운동량 센싱 등의 기능 탑재', '전문가 라인과 일반 라인별 컨셉 및 컨텐츠 개발', '압박 의류 형태로 디자인', '운동지역에 따른 상품개발의 차별화' 등의 상품기획 및 디자인 방향을 제시하였다.

• 복식
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• 제62권8호
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• pp.1-18
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• 2012

The purpose of the study was to offer in-depth understanding of the women's wear research trend in South Korea and thus to provide insights from the findings throughout the study to set appropriate directions for further development of women's wear related researches in the clothing and textile study area. The study considered research papers published by the 6 major apparel related journals listed on the KCI(Korea Citation Index) i.e. journals of the Korean Society of Clothing and Textiles(KSCT), the Korean Society of Costume(KSC), the Costume Culture Association (CCA), the Korean Society of Fashion Business(KSFB), the Korean Home Economics Association (KHEA) and the Korean Society for Clothing Industry(KSCI). A total of 380 research papers that were related with women's wear published from 2001 to 2010 were selected for the study and analyzed in the form of descriptive statistics using the SPSS Software ver. 18.0. The analysis was categorized according to the journals, years and research theme. The research themes were divided into various categories such as, clothing construction, textile science, fashion aesthetics and design, costume history and culture, apparel psychology and fashion marketing. The results derived from the research were: (1) the ratio of the research papers on the women's wear to the total papers published from 2001 to 2010 by the 6 subject journals was 380 to 6,815, i.e. 5.6% of the total papers; (2) journal of KSCT published the most women's wear research papers (N=149, 39.2%) and then the rest in order were the journal of CCA (N=69, 18.2%), the journal of KSC (N=68, 17.9%), the journal of KSFB (N=52, 13.7%), the journal of KHEA (N=39, 10.3%) and the journal of KSCI (N=3, 0.7%); (3) the proportions of the research themes for the women's wear study were in the order of the case study in marketing (N=135, 35.5%), body measurements and sizing systems in clothing construction (N=88, 23.2%), fashion design and aesthetics (N=83, 21.8%), pattern-making (N=63, 16.6%), and color study (N=11, 2.9%) and so on.

• Tribology and Lubricants
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• 제11권5호
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• pp.128-135
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• 1995

Atomic force microscopy/friction force microscopy (AFM/FFM) techniques are increasingly used for tribological studies of engineering surfaces at scales, ranging from atomic and molecular to microscales. These techniques have been used to study surface roughness, adhesion, friction, scratching/wear, indentation, detection of material transfer, and boundary lubrication and for nanofabrication/nanomachining purposes. Micro/nanotribological studies of single-crystal silicon, natural diamond, magnetic media (magnetic tapes and disks) and magnetic heads have been conducted. Commonly measured roughness parameters are found to be scale dependent, requiring the need of scale-independent fractal parameters to characterize surface roughness. Measurements of atomic-scale friction of a freshly-cleaved highly-oriented pyrolytic graphite exhibited the same periodicity as that of corresponding topography. However, the peaks in friction and those in corresponding topography were displaced relative to each other. Variations in atomic-scale friction and the observed displacement has been explained by the variations in interatomic forces in the normal and lateral directions. Local variation in microscale friction is found to correspond to the local slope suggesting that a ratchet mechanism is responsible for this variation. Directionality in the friction is observed on both micro- and macro scales which results from the surface preparation and anisotropy in surface roughness. Microscale friction is generally found to be smaller than the macrofriction as there is less ploughing contribution in microscale measurements. Microscale friction is load dependent and friction values increase with an increase in the normal load approaching to the macrofriction at contact stresses higher than the hardness of the softer material. Wear rate for single-crystal silicon is approximately constant for various loads and test durations. However, for magnetic disks with a multilayered thin-film structure, the wear of the diamond like carbon overcoat is catastrophic. Breakdown of thin films can be detected with AFM. Evolution of the wear has also been studied using AFM. Wear is found to be initiated at nono scratches. AFM has been modified to obtain load-displacement curves and for nanoindentation hardness measurements with depth of indentation as low as 1 mm. Scratching and indentation on nanoscales are the powerful ways to screen for adhesion and resistance to deformation of ultrathin fdms. Detection of material transfer on a nanoscale is possible with AFM. Boundary lubrication studies and measurement of lubricant-film thichness with a lateral resolution on a nanoscale have been conducted using AFM. Self-assembled monolyers and chemically-bonded lubricant films with a mobile fraction are superior in wear resistance. Finally, AFM has also shown to be useful for nanofabrication/nanomachining. Friction and wear on micro-and nanoscales have been found to be generally smaller compared to that at macroscales. Therefore, micro/nanotribological studies may help def'me the regimes for ultra-low friction and near zero wear.