• 한국염색가공학회지
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• 제25권3호
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• pp.165-171
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• 2013

A new monoazo violet dye optimized for polyolefin fibers such as polypropylene and ultra high molecular weight polyethylene fibers was synthesized and its dyeability was investigated. Two hexyl groups were introduced to coupler, 2,5-dimethoxyaniline, in order to increase hydrophobicity of the dye. The maximum absorption wavelength was appeared at 580nm, which meant that the dye showed violet color. From the dyeing results at various conditions, the optimum dyeing was determined as $130^{\circ}C$ for 1 hour with 5% owf of dyes. The good fastness ratings to washing, rubbing were obtained showing at least 4 for both fibers. Light fastness was acceptable for polypropylene fibers giving ratings 3~4. However, relatively poor light fastness was obtained in case of ultra high molecular weight polyethylene fibers showing ratings 2.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2003년도 international symposium on advanced powder metallurgy
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• pp.12-24
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• 2003

• 한국생산제조학회지
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• 제9권5호
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• pp.34-39
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• 2000

Application of ceramics has grown considerably due to significant improvement in their mechanical properties such as light weight, chemical stability and superior wear resistance. Despite these character, the use of ceramics has not increased because of poor machinability. The method of using of super-abrasives metal bond wheel was proposed. But it is difficult that super-abrasives metal bond wheel can be dressed. Recently, the technology of in-process electrolytic dressing is developed to solve this problem. If this method is applied, loading and glazing are disappeared apparently. The aim of this study is to determine the machining characteristics in terms of lapping wheel speed, machining time, pressurized weight to the workpiece and peak current using in-process electrolytic dressing applied to the CIB-diamond lapping wheel to achieve ultra-precision lapping machining technique.

• Journal of Advanced Marine Engineering and Technology
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• 제37권7호
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• pp.711-717
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• 2013

Titanium (Ti) metal and its alloys are desirable materials for ship hulls and other structures because of their high strength, light weight and corrosion-resistance. And light weight and corrosion-resistant aluminum (Al) is the ideal metal for shipbuilding. The joining of Ti and Al dissimilar metals is one of the effective measures to reduce weight of the structures or to save rare metals. Ti and Al have great differences in materials properties, and intermetallic compounds such as Ti3Al, TiAl, TiAl3 are easily formed at the contacting surface between Ti and Al. Thus, welding or joining of Ti and Al is considered to be extremely difficult. However, it was clarified that ultra-high speed welding could suppress the formation of intermetallic compounds in the previous study. Results of tensile shear strength increases with an increase in the welding speed, and therefore extremely high welding speed (50m/min in this study) is good to dissimilar weldability for Ti and Al. In this study, therefore, full penetration dissimilar lap welding of Ti (upper) - Al (lower) and Al (upper) - Ti (lower) with single-mode fiber laser was tried at ultra-high welding speed, and the microstructure of the interface zones in the dissimilar Al and Ti weld beads was investigated.

• Journal of Advanced Marine Engineering and Technology
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• 제38권2호
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• pp.133-139
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• 2014

Titanium (Ti) metal and its alloys are desirable materials for ship hulls and other ocean structures because of their high strength, corrosion-resistance and light weight properties. And light weight and corrosion-resistant aluminum (Al) is the ideal metal for shipbuilding. The joining of Ti and Al dissimilar metals is one of the effective methode to reduce weight of the structures. Ti and Al have great differences in materials properties, and intermetallic compounds such as $Ti_3Al$, TiAl, $TiAl_3$ are easily formed at the contacting surface between Ti and Al. Thus, dissimilar welding and joining of Ti and Al are considered to be very difficult. However, it was clarified that ultra-high speed welding could suppress the formation of intermetallic compounds in the previous study. Results of tensile shear strength increases with an increase in the welding speed, and therefore extremely high welding speed (50 m/min) is good to dissimilar weldability for Ti and Al. In this study, therefore, full penetration dissimilar lap welding of Ti (upper) - Al (lower) and Al (upper) - Ti (lower) with single-mode fiber laser was tried at ultra-high welding speed, and the microstructure of the interface zones in the dissimilar Al and Ti weld beads was investigated.

• 한국의류산업학회지
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• 제7권1호
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• pp.111-114
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• 2005

In this the study, polyester/cotton(P/C) blended fabrics with fine denier were developed to get the light weight compared with the traditional P/C blended fabrics. Moreover, the width of the fabrics was extended by the tenter during the final heat treatment to get the lower fabric density and lighter weight. Then, the physical properties of these fabrics were analysed. The results were as the follows: The developed fabrics had 22.6-31.6% lighter weight than the traditional fabrics with the same fabric width. The weight of fabric decreased drastically with the fabrics width down to 67.1 $g/m^2$. The fabric density for the warp direction decreased with the fabric width. The tenacity and the elongation of the developed fabrics was little lower than that of the traditional fabrics. The air permeability of the developed fabrics increased with that of the traditional fabrics. The stretch rate of the developed fabrics decreased with increasing the fabric width. Residual stretch rate of the developed fabrics was more stable than that of the traditional fabrics. Residual stretch rate of the developed fabrics increased with the fabric width, but the highest value was less than 5% which is quit stable.

• 한국염색가공학회지
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• 제27권1호
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• pp.27-34
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• 2015

Novel super hydrophobic disazo red dyes were synthesized to improve light fastness of the primary monoazo red dye of previous study on polyolefin fibers such as polypropylene and ultra high molecular weight polyethylene fibers. 4-Alkylanilines were diazotized and then coupled to 2,5-dimethylaniline to produce dye intermediates which were then further used to synthesize final disazo red dyes by diazoization and coupling to ${\beta}$-naphthol. Considering both affinity of the dyes toward both polyolefin fibers and color fastnesses, the decyl-substituted dye was determined as the optimum dye. The decyl-substituted disazo red dye exhibited good dyeability on both polyolefin fibes and almost the same color values as the previous primary monoazo red dye. Light fastness on ultra high molecular weight polyethylene fibers was improved up to rating 3~4 compared to rating 2~3 of the previous primary monoazo red dye.

• 한국염색가공학회지
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• 제23권2호
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• pp.76-82
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• 2011

Ultra High molecular weight polyethylene(UHMWPE) films were photooxidized by UV/ozone irradiation. Reflectance of the irradiated films decreased in the low wavelength regions of visible light, indicating destructive interference of visible light due to roughened surface. The UV treatment developed the nano-scale roughness on the UHMWPE films surface, which increased by two-fold from 82.6 to 156.6nm in terms of peak-valley roughness. The UV irradiation caused the oxygen content of the UHMWPE film surface to increase. Water contact angle decreased from $83.2^{\circ}$ to $72.9^{\circ}$ and surface energy increased from 37.8 to 42.6mJ/$m^2$ with increasing UV energy. The surface energy change was attributed to significant contribution of polar component rather than nonpolar component indicating surface photooxidation of UHMWPE films. The increased dyeability to cationic dyes may be due to the photochemically introduced anionic and dipolar dyeing sites on the film surfaces.

• Journal of Advanced Marine Engineering and Technology
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• 제32권2호
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• pp.343-350
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• 2008

In this paper, a six degree-of-freedom robot arm which is very light but capable of delivering heavy loads was studied. The proposed robot arm has much higher load capacity than conventional robot arms actuated by motors with speed reducers such as the harmonic drive since a new type of robot actuator based on a closed chain mechanism driven by the ball screw was adopted. Analysis on the design scheme and on the mechanism of the joint actuator of the robot arm were made. Since the robot arm was designed very light, it has deflection in the links. To analyze this, a finite element analysis on the structure of the designed robot links was made using ANSYS software. Verifying experiments on the performance of high load capacity of the robot arm was performed by loading heavy weights on the robot arm. Through experiments. the correctness of the numerical analysis was also verified.

• 한국염색가공학회지
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• 제24권3호
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• pp.180-188
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• 2012

Following the reported study that showed the dyeability of diamino-anthraquinoid blue dyes substituted with relatively shorter alkyl groups, the longer aliphatic substituents than pentyl group were examined in terms of the color strength and fastness properties toward UHMWPE fibers. The color strength was increased up to pentyl group and then gradually decreased. However, the fastness properties were improved continuously to octyl group which was the longest alkyl substituent in this study. The most effective maximum color strength was obtained at $130^{\circ}C$ for 2 hours with 3% owf of dyes. The overall fastnesses to washing, rubbing, and light were good enough for practical uses.