• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.102-106
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• 1996

In the ball end-milling process of a 3-dimensional mold, it is important to select cutting conditions and tool path considering the geometrical shape of a workpiece to reduce machining time. In this study, experiments were performed to decide allowable feed rate not breaking stability of system for different geometrical shapes. It was found that downcut is more stable than upcutting in machining side wall and downward is preferable to upward in inclined part depending on the angle of the inclination and depth of cut.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권3호
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• pp.228-234
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• 2016

Recent icebreaking ships need to be designed to enhance not only icebreaking capability but also turning ability. For the evaluation of ice resistance induced by an icebreaking hull form, HHI (Hyundai Heavy Industries) has developed the hybrid empirical formulas (Park et al., 2015) by considering the geometrical hull shape features, such as waterline and underwater sections. However, the empirical formulas have inherent limits to the precise estimation of the icebreaking and turning ability because the breaking process and the resulting pattern are ignored. For this reason, numerical calculation in time domain is performed to predict the icebreaking process and pattern. In the simulation, varying crushing stress according to velocity vectors and contact areas between hull and ice is newly introduced. Moreover, the simulation results were verified by comparing them with the model test results for three different bow-first icebreaking models.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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• pp.224-225
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• 2000

Transparent and hard materials such as sapphire are used for many industrial applications as optical windows, hard materials on mechanical contact against abrasion, and substrate materials for opto-electronic semiconductor devices such as blue LED and blue LD etc. The materials should be cut along the proper shapes possible to be used for each application. In case of blue LED, the blue LED wafer should be cut to thousands of blue LED pieces at the final stage of the manufacturing process. The process of cutting the wafer is usually divided into two steps. The wafer is scribed along the proper shapes in the first step. It is inserted between transparent flexible sheets for easy handling. And then, it is broken and split in the next step. Harder materials such as diamonds are usually used to scribe the wafer, while it has a problem of low depth of scribing and abrasion of the harder material itself. The low depth of scribing can induce failure in breaking the wafer along the scribed line. It was also known that the expensive diamond tip should be replaced frequently for the abrasion. (omitted)

• 한국기계가공학회지
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• 제12권1호
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• pp.15-21
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• 2013

The safety and stability of 5MW class offshore wind turbine Jack-up platform was investigated through ocean basin experiment. For simulating the environmental condition of yellow sea in the South Korea, diverse waves, winds and currents were performed based on Froude's number. Regular wave and irregular wave based on Froude's number were applied to the wind turbine structure. In experiments, the height and period of regular wave type were scaled down as the 1:50 ratio of real wave condition. Irregular wave type was simulated with TMA(Texel Storm, Marsen and Arsloe)spectrum. The vertical reaction force, resonance period and wave pressure applied to multi-supporters of wind offshore structure were measured experimentally. Finally, the results showed that the capsizing situation of the offshore structure was generated by the severe environmental condition.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.433-440
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• 2006

A fiber processing method, which might be an alternative for conventional refining process, was introduced. The method consists of repetitive, gentle, mechanical impacts on fiber, and ensued fiber uncurling process. This method was very effective for OCC and BCTMP for increasing WRVs (water retention value) while keeping fiber lengths from shortening. For OCC and BCTMP, gentle mechanical impacts on fibers using Hobart mixer increased breaking lengths and tear strengths simultaneously at fast drainage level, and straightening fibers using kady mill increased those strength properties further. For SwBKP and HwBKP, only mechanical impacts using the mixer were effective on increasing tensile and tear strength at fast drainage, but not kady mill treatment. The strength increases of BCTMP by this alternative fiber processing method were exceptionally high. An extensive engineering development should be followed to actualize this fiber processing mechanism in an energy-effect way.

• 한국염색가공학회지
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• 제18권2호
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• pp.31-38
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• 2006

Silk fabrics are very popular and widely used because of their elegant appearance. However, silk fabrics generally have easy wrinkle, and do not stretch and deform permanently after machine washing. Then the stretched properties of silk fabrics are important for the application of industrial textile materials such as formal and sports wear. Thus, this research surveys the covering, weaving and degumming conditions for stretched silk fabrics. As a result, yarn breaking stress was reduced with increasing spindle speed, and the yarn twists were optimized under the covering condition of polyurethane/silk with PVA pretreatment. In addition, the shrinkage of the silk fabrics treated with star degumming process was reduced by continuous NaOH degumming process. The fabrics showed the fabric physical properties with optimum stretched properties and evenness surfaces.

• 복식문화연구
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• 제7권5호
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• pp.46-55
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• 1999

This research, as a study of the documentary records, examined the process of men\`s wear development year by year, looking into the newspapers which show objectively social phenomena in those days. The outcomes therefrom were classified according to the important factors of dress and ornaments\` modeling i. e. style, color, pattern, material, ornamentation method. And then, the process of men\`s wear transition was analyzed based on the aforesaid examination with its classification. The above analyses revealed that a transition of a dress and ornaments closely correlates with a social and cultural change and also meant that the dress and ornaments symbolizes the social phenomena in those days. Thanks to the holding of Seoul Olympic Games in 1988, Korean society had tremendously grown with rapid changes in its politics, economy and culture. Also, men\`s wear type became innovative, breaking from the existing orthodox one due to the transition of men\`s viewpoints on value and their lives\` style.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권3호
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• pp.115-118
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• 2006

In the steel industry, a steel melting electric arc furnace is used to produce both carbon and alloy steels. Steel scrap which is charged into the furnace is heated by means of electric arc between graphite electrodes and the scrap. In this melting process, current is supplied to the furnace through HCC(high current cable) which connect the furnace and transformer. Four HCCs are assigned to each phase in our system to divide the current. Since a sudden cable breaking result in the shutdown of melting process, an aging detection of HCC is very important for both an improvement of productivity and cost reduction. In this paper, the aging of the HCC is estimated by using the current ratio between four HCCs.

• 조명전기설비학회논문지
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• 제28권1호
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• pp.29-35
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• 2014

The purpose of this paper is the rotor design of a single-phase LSPM(Line-start permanent magnet) motor. A single-phase LSPM motor has a permanent magnet in the rotor that is same as induction motor. For that reason, magnet is operated by breaking torque in starting region and alignment torque in driving region. Therefore, we need the design process considering the trade-off relationship. In this paper, we propose the design process of a single-phase LSPM motor for a high starting torque and efficiency with FEM. And we use Taguchi Method for considering tolerance in manufacture. Finally, we compared the LSPM motor that is designed in this paper and conventional induction motor.

• 전기학회논문지P
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• 제57권4호
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• pp.451-456
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• 2008

In this paper. we experimented and analyzed about evaporation and breaking process of filament by external flames and adsorption pattern in lamp bulb of evaporated filament particle according to the set-up directions of incandescent lamps. In the results of experiments, we could know that filament evaporation behavior of incandescent lamp that is established by down direction happened most vigorously and is difference in adsorption pattern of filament particle that is vaporized according to set-up directions. Also, glass bulbs were melted and filaments were evaporated by external flames, and finally molten marks were discriminated. We expect that become important data that this study finding reveals burnout cause of incandescent lamp in scene of a fire.