• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1803-1806
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• 2003

Metalworking fluids (MWFs) are fluids used during machining and grinding to prolong the lift of the tool, carry away debris, and protect the surfaces of work pieces. These fluids reduce friction between the cutting tool and the work surface. reduce wear and galling, protect surface characteristics, reduce surface adhesion or welding and carry away generated heat. Workers can be exposed to MWFs by inhaling aerosols (mists) and by skin contact with the fluid. Skin contact occurs by dipping the hands into the fluid, splashes, or handling workpieces coated with the fluids. The amount of mist generated (and the resulting level of exposure) depends on many factors. To reduce the environmental pollution wastes and the potential health risks associated with occupational exposures to MWFs, it is required to establish optimum MWFs supply method and condition with minimum quantity in all over the mechanical machining field including high-speed type heavy cutting process.

• 한국생산제조학회지
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• 제24권6호
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• pp.599-604
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• 2015

Currently, the coolant system in industrial sites is an efficient process to keep clean cutting oils. However, the damage to a pump occurs due to a chip and debris when inhaled into the pump, and thus problems such as the reduction of both efficiency and lifespan might arise. In this study, a new type of filter was developed in order to primarily prevent the damage from the pump impeller and make it unnecessary to have the replacement and cleaning at the same time. This study found the problem reducing the suction volumetric efficiency and cavitation when inhaled, and conducted a method to solve the problem compared to the result of fluid analysis according to two velocity conditions. As a result, this study achieved the effect of lowering the pressure and meeting the suction flow rate by connecting the four filters.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1566-1570
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• 2005

The aspherical lenses are used as optical lens of HMD optical system. The optimum cutting condition of PMMA lens sample with ultra precision SPDT, the diamond tool nose radius, the cutting speed, the feed rate, the depth of cut, and cutting fluid type are found. The demanded surface roughness 10 nm Ra, aspherical form error $1.0\;\mu{m}$ P-V for aspherical lens of optical data storage device are satisfied.

• Wind and Structures
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• 제35권5호
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• pp.309-322
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• 2022

Due to the complex terrain around high-speed railways, the windbreaks were established along different landforms, resulting in irregular windbreak transition regions between different subgrade infrastructures (flat ground, cutting, embankment, etc). In this paper, the effect of a windbreak transition on the wind flow around railways subjected to crosswinds was studied. Wind tunnel testing was conducted to study the wind speed change around a windbreak transition on flat ground with a uniform wind speed inflow, and the collected data were used to validate a numerical simulation based on a detached eddy simulation method. The validated numerical method was then used to investigate the effect of the windbreak transition from the flat ground to cutting (the "cutting" is a railway subgrade type formed by digging down from the original ground) for three different wind incidence angles of 90°, 75°, and 105°. The deterioration mechanism of the flow fields and the reasons behind the occurrence of the peak wind velocities were explained in detail. The results showed that for the windbreak transition on flat ground, the impact was small. For the transition from the flat ground to the cutting, the influence was relatively large. The significant increase in the wind speeds was due to the right-angle structure of the windbreak transition, which resulted in sudden changes of the wind velocity as well as the direction. In addition, the height mismatch in the transition region worsened the protective effect of a typical windbreak.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.206-208
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• 2002

Metalworking fluids (MWFs) are fluids used during machining and grinding to prolong the life of the tool , carry away debris, and protect the surfaces of work pieces. These fluids reduce friction between the cutting tool and the work surface, reduce wear and galling, Protect surface characteristics, reduce surface adhesion or welding and carry away generated heat. Workers can be exposed to MWFs by inhaling aerosols (mists) and by skin contact with the fluid. Skin contact occurs by dipping the hands into the fluid, splashes, or handling workpieces coated with the fluids. The amount of mist generated (and the result ins level of exposure) depends on many factors. To reduce the potential health risks associated with occupational exposures to MWFs, it is required to establish optimum MWFs supply method and condition with minimum Quantity in all over the mechanical machining field including high speed type heavy cult ing process.

• International Journal of Precision Engineering and Manufacturing
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• 제8권1호
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• pp.11-15
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• 2007

Composite materials are widely used to make all kinds of machine parts, internal and structural materials of cars, aerospace components, building structures, ship materials, sporting goods and others, It is worth while to use composite space substitute material in various applications when compared with others. But the use of composite material is limited in the field of the mechanical processing because of the difficulties in processing. Thus, it is proved that the surface is rough at the in and out sections of the hole processing when the GFRP is machined with HSS drill in the vertical machining center. And it is observed that the more it is processed, the more the fluid type long chip is changed into the powdered chip.

• 한국기계가공학회지
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• 제2권2호
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• pp.37-44
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• 2003

Composite materials are widely used to make all kinds of machine parts, internal and structural materials of cars, aerospace industries, building structures, ship materials, sporting goods and others. It is worth the while to use composite materials as various substitutions when compared With others. But the use is limited in the field of the mechanical processing because of its difficulties in cutting. The surface roughness of in and out in the hole processing was discussed after cutting the GFRP with HSS drill in the vertical machining center. And it is observed that as it processed more, the powdered chip may be got more than the fluid type long chip.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2001년도 발생공학 국제심포지움 및 학술대회 발표자료집
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• pp.56-56
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• 2001

This study was carried out to investigate on the improvement of fertilizing and developing ability of in vitro matured oocytes from individuals of bulls, sperm type, pretreatment of sperm or oocytes obtained by intracytoplasmic sperm injection(ICSI). 1. The male pronuclear formation and developmental rates of oocytes obtained by ICSI treated individual of bulls were 73.9%-87.0% and 33.3%-60.9%, respectively. 2. The male pronuclear formation and developmental rates of oocytes obtained by ICSI treated fresh and frozen sperm, tail-cutting and tail-scoring sperm were 82.0%, 78.0%, 42.2%, 51.1% and 56.0%, 42.0%, 17.8%, 22.2% respectively. and these values of fresh sperm injection were higher than that of frozen sperm, tail-cutting and tail-scoring. 3. The male pronuclear formation and developmental rates of oocytes obtained by sperm pretreated heparin, BFF(bovine follicula fluid), His, Ca Ionophore(Ⅰ) and Ⅰ ＋ caffeine methods were 66.7%-82.2% and 33.3%-60.6%, respectively. and these values of treatment of Ⅰ＋ caffeine were higher than that of other methods. 4. The male pronuclear formation and developmental rates of oocytes obtained by ICSI treated with or without zona pellucida were 80.0%, 72.0% and 46.0%, 36.0%, respectively.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.407-410
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• 1995

Many researches on measurement technology has been made and developed by various methods. Considering the measurement environment with cutting fluid, coolant and the like, contact type measurement methods are mostly used. But contact measurement method has measuring force and so the sensing head becomes worn. By these reasons, we considered sensors not influenced by the former fluid and so can acquire accrate measured values using error compensation due to temperature and vibration. For this purpose, eddy current sensors and Extended kalman Filter Algorithm for processing measured data has been used. In this paper, we present new technology that can be used for measuring workpiece with previous bad environment using direct method and comparison measurement method. We used cylindrical workpieces which were produced by grinding machine for the target.

• 드라이브 ㆍ 컨트롤
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• 제15권3호
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• pp.29-35
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• 2018

This paper presents the design of attachments for dual arms of disaster responding heavy machine. The heavy machine handles a variety of tasks such as cutting, shredding, picking and moving in unstructured environment. Despite the need for rapid response, the heavy machine has difficulty in repeatedly replacing the attachment depending on the task. Thus, we propose a method to solve this physical and functional contradiction relation by using TRIZ separation principles. Above all, the existing equipment and the required working scenarios were surveyed and summarized in order to separate the attachments functionally for right-handed, left-handed and two-handed operation. Then, we proposed the design directions and conceptual design as following: multi function type attachment A, for precise operation and various operations; grab type attachment B, for grasping irregular objects and auxiliary device for both arms to handle bulky objects.