• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.67-70
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• 2005

The carbon fiber reinforced/epoxy laminated composites were fabricated with initial fiber failures within the unidirectional fiber pre-pregnated ply. The fiber failures were made intentionally either parallel to and/or perpendicular to the unidirectional fibers within the ply. The pre-made clear-cut cracks were found to be healed partially after laminating process. The laminates were impacted with or without initial fiber failures within the laminates. The force versus deflection curves were compared. The partially healed laminates showed the reduced laminate stiffness as compared to those without any intentional fiber failures. The impact curves were compared with size and the location of the initial failures varied.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.245-248
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• 2005

During manufacturing thick composite cylinders, large thermal residual stresses are developed and induce catastrophic interlaminar failures. Since the residual stresses are dependent on many process parameters, such as temperature distribution during cure, cure shrinkage, winding tension, and migration of fibers, calculation of the residual stresses is very difficult. Therefore a radial-cut method have been used to measure the residual stresses in the composite cylinders. But the conventional radial-cut method needs to know numerous material properties which are not only troublesome to obtain but also vary with change of fiber arrangement during consolidation. In this paper, a new radial-cut method with cut-cylinder-bending test was proposed and the measured residual stresses were compared with calculated thermal residual stresses. It was found that the new radial-cut method which does not need to know any of material properties gave better estimation of residual stresses regardless of radial variation of material properties. Additionally, interlaminar tensile strength could be obtained by the cut-cylinder-bending test.

• Journal of Biosystems Engineering
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• 제34권4호
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• pp.228-233
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• 2009

In order to cut the round bale easily, a roughage cut-feeder for the round bale was developed in this study. This study consists of two parts. One is development of a cutting mechanism and a performance test reported in the previous paper. This is the second part of the study. For the study, recent trend of traditional cutting system was analyzed. Also, cost of the prototype cut-feeder was analyzed and determine the break-even point of farm size was determined by comparing with traditional method using a traditional cutter. A prototype cut-feeder was investigated with the fact that working performance, fiber length and shape of roughage and feeding quality was good. Operating cost of the prototype cut-feeder decreased rapidly with an increase of farm size. Break-even point in terms of farm size was 36 heads for beef and 28 heads for dairy. Also, costs estimated were 118,000 won/head year and 148,000 won/head year, respectively.

• 한국초지조사료학회지
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• 제20권3호
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• pp.169-176
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• 2000

This experiment was carried out to investigate the effects of application levels of food waste compost andmineral nitrogen in 3 cuttings per annurn on the nutritive value and nutrient yields of orchardgrass (Dactylisglomerata L.). Annual food waste compost (FWC) and mineral nitrogen were applied at levels of 0, 10, 20,40 and 60 ton ha-', and 0, 90, 180 and 270 kg ha-', respectively. The contents of crude protein (CP, %) oforchardgrass were significantly higher at the application levels of 40 ton ha-' yr-' by FWC than those atapplication levels of 0 ton ha-' yr-' (p<0.05), the contents of neutral detergent fiber (NDF, %), acid detergentfiber (ADF, %) and hemicellulose were also higher in FWC applied plots, except for the FWC levels of 10and 60 ton ha-' yr-'. The contents of total digestible nutrient (TDN, %) and relative feed value (RFV) oforchardgrass were significantly higher at FWC levels of 10 and 60 ton ha-' yr-' than at levels of 0 ton ha"yr-'. Annual yields of CP and TDN were increased with increase the FWC levels. The highest contents ofCP of orchardgrass were obtained at 1st cut, NDF and ADF at 2nd cut. As the mineral nitrogen fertilizationwas increased, the contents of CP, NDF, ADF and hemicellulose of orchardgrass were significantly increased,but TDN and RFV were decreased. .Annual yields of CP and TDN of orchardgrass were significantlyincreased with increase the mineral nitrogen fertilization.(Key words : Food waste compost, Mineral nitrogen, Crude protein, Neutral detergent fiber, Acid detergentfiber)rgent fiber, Acid detergent fiber)

• 소성∙가공
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• 제15권6호
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• pp.436-440
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• 2006

A rapid tooling (RT) method fur the resin transfer molding (RTM) have been investigated. We fabricated a curved I-beam to verify the method. After creating a three-dimensional CAD model of the beam we fabricated a prototype of the model using a rapid prototyping (RP) machine. A soft mold was made using the prototype by the conventional silicone mold technique. The procedure and method of mold fabrication is described. The mold was cut into several parts to allow easier placement of the fiber preform. We conducted the resin transfer molding process and manufactured a composite beam with the mold. The preform was built by stacking up eight layers of delicately cut carbon fabrics. The fabrics were properly stitched to maintain the shape while placement. The manufactured composites beam was inspected and found well-impregnated. The fiber volume ratio of the fabricated beam was 16.85%.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.441-446
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• 2000

Although the net-shape molding of composites is generally recommended, molded composites frequently required cutting or grinding due to the dimensional inaccuracy for precision machine elements. During the composite machining operations such as cutting and grinding, the temperature at the grinding area may increase beyond the allowed limit due to the low thermal conductivity of composites, which might degrade the matrix of composite. Therefore, in this work, the temperature at the grinding point during surface grinding of carbon fiber epoxy composite was measured. The grinding temperature and surface roughness were also measured to investigate the surface grinding characteristics of the composited. The experiments were performed both under dry and wet grinding conditions with respect to cutting speed, feed speed, depth of cut and stacking angle. From the experimental investigation, the optimal conditions for the composite plain grinding were suggested.

• 한국생산제조학회지
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• 제9권6호
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• pp.65-70
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• 2000

Although the net-shape molding of composites is generally recommended, molded composites frequently requires cutting or grinding due to the dimensional inaccuracy for precision machine elements. During the composite machining operations such as cutting and grinding, the temperature at the grinding area may increase beyond the allowed limit due to the low thermal conductivity of composites, which might degrade the matrix of composite. Therefore, in this work, the temperature at the grinding point during surface grinding of carbon fiber epoxy composite was measured. The grinding temperature and surface roughness were also measured to investigate the surface grinding characteristics of the composites. The experiments were performed both under dry and wet grinding conditions with respect to cutting speed, feed speed, depth of cut and stacking angle. From the experimental investigation, the optimal conditions for the composite surface grinding were suggested.

• 한국정보기술학회 영문논문지
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• 제9권1호
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• pp.103-113
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• 2019

Motivation: Polymerized actin-based cytoskeletal structures are crucial in shape, dynamics, and resilience of a cell. For example, dynamical actin-containing ruffles are located at leading edges of cells and have a significant impact on cell motility. Other filamentous actin (F-actin) bundles, called stress fibers, are essential in cell attachment and detachment. For this reason, their mechanistic understanding provides crucial information to solve practical problems related to cell interactions with materials in tissue engineering. Detecting and counting actin-based structures in a cellular ensemble is a fundamental first step. In this research, we suggest a new method to characterize F-actin wrapping fibers from confocal fluorescence image stacks. As fluorescently labeled F-actin often envelope the fibers, we first propose to segment these fibers by diminishing an energy based on maximum flow and minimum cut algorithm. The actual actin is detected through the use of bilateral filtering followed by a thresholding step. Later, concave actin bundles are detected through a graph-based procedure that actually determines if the considered actin filament is enclosing the fiber.

• 한국공작기계학회논문집
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• 제10권3호
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• pp.38-42
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• 2001

In the machining of glass fiber reinforced plastics(GFRP), turning has been often used. But the most of past studies have been interested in the effect of fiber orientation on tool wear. In this study, the effects of fiber contents and cutting speeds on tool wear, cutting force and surface roughness are investigated experimentally. By proper selection of cutting tool, the variables are cutting speed, fiber contents and cutting length with fixed feed rate and depth of cut. The fiber contents have major effects on coated tool wear which observed as abrasive wear type.

• 한국생산제조학회지
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• 제9권3호
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• pp.90-95
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• 2000

Today fiber composite materials are routinely used in such wide applications as ships automobiles aircraft space vehi-cles containers sporting goods and appliances. The current knowledge of machining glass fiber reinforced polyester com-posites unfortunately is inadequate for its optimum utilization in many applications. Therefore This paper deals with drilling characteristic of glass fiber reinforced polyester composites. In the drilling of glass fiber reinforced polyester the quality of the cut surfaces is strongly dependent on the drilling parameters. drilling tests were carried out on glass fiber reinforced polyester using standard HSS tools. The material containing random chopped strand fibers and woven roving was fabricated by hand lay-up The entrance and exit surface of the holes was examined. The cutting force was also mea-sured to analyze the drilling characteristics,.