• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권1호
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• pp.50-54
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• 2006

The study on discharge of the flat lamp lighting source has been requested increasingly. To improve the brightness, life time and efficiency of flat lamp, the plasma diagnosis of flat lamp lighting source is very important. When a distance of discharge electrode is 5.5mm and width is 16.5mm, we measured electron temperature and electron density with single Langmuir probe in flat lamp. Pressure conditions to test the plasma discharge from 100 Torr to 300 Torr. The power supply was PDS-4000 with frequency 20kHz and duty ratio $20\%.$ Form these experimental results, electron temperature was decreased according to increase the gas pressure and the voltage while electron density was increased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2190-2192
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• 2005

Discharge of the flat lamp lighting source research are requested very much. For improving brightness, life time, efficiency of flat lamp, plasma diagnosis of the flat lamp lighting source to understand property of lighting source is very important. distance of discharge electrode is 5.5mm and width is 16.5mm, we measured electron temperature and electron density measured with single langmuir probe in flat lamp. we tested the discharge from 100 Torr to 300 Torr pressure. the Pulse is rectangular pulse with frequency 20kHz and Duty ratio 20%. Resultly, electron temperature decreases and electron density increase as increase the gas pressure and electron temperature decreases and electron density increase as increase the voltage.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.572-573
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• 2005

Discharge of the flat lamp lighting source research are requested very much. For improving brightness. life time. efficiency of flat lamp and plasma diagnosis of the flat lamp lighting source to understand property of lighting source is very important. When a distance of discharge electrode is 5.5mm and width is 16.5mm. we measured electron temperature and electron density measured with single Langmuir probe in flat lamp. We tested the discharge from 100 Torr to 300 Torr pressure. The pulse type was rectangular with frequency 20kHz and duty ratio was 20%. In result. electron temperature decreases and electron density increased as increase the gas pressure and electron temperature decreases and electron density increase as increase the voltage.

• 펄프종이기술
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• 제41권5호
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• pp.8-14
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• 2009

Corrugated fiberboard is a widely used packaging material because of its high compressive strength and stiffness despite light weight. Corrugated fiberboards with microflutes with height $\leq$ 1.5 mm, such as E, F or G, have been developed. As microflutes have a different geometry from other conventional flutes, they may behave differently in testing and require a new testing method. Therefore, we evaluated the flat crush resistance of corrugated fiberboard with microflutes according to the ISO and TAPPI standard test methods. In addition, the effects of specimen area and platen compression rate were examined. The goal of this study was to identify an appropriate method for flat crush test (FCT) of corrugated fiberboard with microflutes. When a test piece with a standard area was subjected to the FCT in accordance with ISO and TAPPI methods, microflute corrugated fiberboard demonstrated a different load-displacement curve. An area of 20 $cm^2$ was determined to be the most appropriate for FCTof microflute corrugated fiberboard.

• 한국정밀공학회지
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• 제27권8호
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• pp.35-41
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• 2010

White Etching Layer(WEL) is a phenomenon that occurs on the surface of rail due to wheel/rail interactions such as excessive braking and acceleration. Rolling Contact Fatigue(RCF) cracks on the surface of rail have been found to be associated with WEL. In this study, we have investigated RCF damages of white etching layer using twin disc testing and fatigue analysis. These tests consist of wheel flat tests and rolling contact fatigue tests. WEL has been simulated by wheel flat test. It has been founded that the WEL with a bright featureless contrast is formed on the surface of specimen by etching. Rolling contact fatigue test was conducted by using flat specimens with the WEL generated by the wheel flat test. It has been observed that two types of cracks occur within the specimen. The contact fatigue test was simulated in 2D elastic-plastic FE simulations. Based on loading cycles obtained from the finite element analysis, the fatigue life analysis according to the thickness variation of WEL was carried out. The longest fatigue life was observed from the thickness of 20um.

• Ocean and Polar Research
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• 제38권4호
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• pp.315-324
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• 2016

In this study, we investigated changes in the macrobenthic community in Sihwa tidal flat before and after the operation of a Tidal Power Plant (TPP). In order to investigate changes in the macrobenthic community structure, field surveys were conducted at eighteen stations in 4 transect lines every September from 2011 to 2015. Mean density of macrobenthos decreased to $116ind./m^2$ in 2015 from $1,602ind./m^2$ in 2011. While the mean density of macrobenthos has decreased, species richness and biomass have gradually increased. The species diversity and SEP (Shannon-wiener Evenness Proportion) have also gradually increased over time since the operation of the TPP. The macrobenthic community in Sihwa tidal flat was divided into 4 groups on a yearly base. Before the operation of TPP, opportunistic species such as Neanthes succina and Polydora cornuta largely contributed to the structure of the macrobenthic community, while equilibrium species such as Periserrula leucophryna and Scopimera globosa contributed after the operation. With the operation of TPP, the macrobenthic community has rapidly recovered and this might be related to improvement in the quality of water and sedimentary environments as a result of an increase in water mass volume exchanged through the TPP gate.

• 공업화학
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• 제26권4호
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• pp.389-393
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• 2015

인듐은 디스플레이 산업의 발전과 더불어 그 수요가 급격하게 증가하고 있으며 산업적 중요도도 높아 보조 공급원으로 부터의 회수기술 개발이 점점 관심을 얻고 있다. 폐 디스플레이 재활용을 위한 인듐 회수기술은 크게 해체분리, 선별농축 그리고 정제 공정으로 구성되어 있으며 목표하는 소재의 최종 순도에 따라 추가적으로 고도화 공정이 도입된다. 본 논문에서는 인듐 회수를 위해 적용되고 있는 기술에 대해서 소개하며 연구동향과 향후 전망 등에 고찰하였다.

• Steel and Composite Structures
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• 제46권6호
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• pp.745-757
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• 2023

In order to study the fatigue performance of the flat steel plate-lightweight aggregate concrete hollow composite bridge slab subjected to fatigue load, both static test on two specimens and fatigue test on six specimens were conducted. The effects of the arrangement of the steel pipes, the amplitude of the fatigue load and the upper limit as well as lower limit of fatigue load on failure performance were investigated. Besides, for specimens in fatigue test, strains of the concrete, residual deflection, bending stiffness, residual bearing capacity and dynamic response were analyzed. Test results showed that the specimens failed in the fracture of the bottom flat steel plate regardless of the arrangement of the steel pipes. Moreover, the fatigue loading cycles of composite slab were mainly controlled by the amplitude of the fatigue load, but the influences of upper limit and lower limit of fatigue load on fatigue life was slight. The fatigue life of the composite bridge slabs can be determined by the fatigue strength of bottom flat steel plate, which can be calculated by the method of allowable stress amplitude in steel structure design code.

• 농업과학연구
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• 제48권4호
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• pp.843-853
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• 2021

The objectives of this paper were to simply estimate soil loss levels as caused by wind in reclaimed tidal flat land (RTFL) and the threshold wind velocity in the RTFL. For this experiment, RTFL located at Haenam Bay was selected and a total of 150 soil samples were collected at the Ap horizon from the five soil series. The particle distribution curves, including the limit of the non-erodible particle size (D > 0.84 mm) for each Ap horizon soil, show that the proportions of non-erodible particle sizes that exceeded 0.84 mm were 4.3% (Taehan, TH), 8.9% (Geangpo, GP), 0.5% (Bokchun, BC), 1.6% (Poseung, PS) and 1.4% (Junbook, JB), indicating that the amount of non-erodible soil particles increased with an increase in the sand content. The average monthly, daily and instantaneous wind velocities were higher than the threshold friction velocity (TFV) calculated according to the dynamic velocity (V_d) by Bagnold, while the average monthly wind velocity was lower than those of the TFV suggested by the revised wind erosion equation (RWEQ) and wind erosion prediction system (WEPS). The susceptible proportions of erodible soil particles from the Ap horizon soil samples from each soil series could be significantly influenced by the proportion of sand particles between 0.025 and 0.5 mm (or 0.84 mm) in diameter regardless of the threshold wind velocity. Thus, further investigations are needed to estimate more precisely soil erosion in RTFL, which shows various soil characteristics, as these estimations of soil loss in the five soil series were obtained only when considering wind velocities and soil textures.

• 한국생산제조학회지
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• 제21권6호
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• pp.982-987
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• 2012

Inconel 718 alloy has been widely used in the aerospace, heavy industry and electronic industry. However, the machinability of this alloy is very poor, which is attributed to their inherent high strength that is maintained at elevated temperatures. The tool life is dominant problem in machining difficult-to-cut materials, so it is necessary to select the efficient cutting conditions for the improvement of tool life. In this study, the cutting force, tool wear and surface roughness are investigated in end milling machining under various cutting conditions. By this experiment, the efficient machining condition of this alloy is suggested to adopt in various industries.