• Title/Summary/Keyword: Green body

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Micro-drilling of alumina green body with diamond abrasive drills (다이아몬드 입자 전착 드릴에 의한 알루미나 성형제의 미소구멍가공)

  • 이학구;방경근;김포진;이대길
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.926-931
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    • 2002
  • Although ceramic plates with many micro-hales are used as MCP (Micro-channel plate) for electron amplification, catalytic converters, filters, electrical insulators and thermal conductors in integrated circuits, the drilling of micro-hales in the ceramics is difficult because of their low thermal conductivity, high hardness and brittleness. Therefore, in this work, the machining of ceramic green body fellowed by sintering of green body was employed fur fabricating ceramic plates with many micro-holes. The micro-drilling of alumina green body was performed with diamond abrasive WC drills, and the cutting force w.r.t. drilling times was measured for the determination of toot life. From the investigation of the wear of micro-drill tip w.r.t. drilling times, the wear mechanism of tip during micro-drilling of ceramic green body was suggested.

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Study on the Electric Continuity Measurements of Green Car for Human Body Safety (친환경자동차의 인체 안전을 위한 전기적 연속성 측정 연구)

  • Kim, Hyang-Kon;Lee, Ki-Yeon;Kim, Dong-Ook;Choi, Hyo-Sang
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.3
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    • pp.351-356
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    • 2009
  • In this study, we analyzed and experimented about electric continuity for human body safety from green cars. And we compared power systems of HEV and examined about human body effect of current and time. We investigated internal and external standards and regulations for human body safety from high voltage electrical equipments. Indirect contact refers to contact between the human body and exposed conductive parts. According to UNECE R100, ISO 23273-3, ISO 6469-3 and Japanese Regulation Attachment 101, electric continuity between any two exposed conductive parts shall not exceed $0.1{\Omega}$. The value of electric continuity was measured below $0.1{\Omega}$ at the actual condition of green car. We expected that the results of these experiments can utilize to data for electrical safety of green car.

FE Analysis of Alumina Green Body Density for Pressure Compaction Process (압축성형공정에 대한 알루미나 성형체 밀도분포의 FE 분석)

  • Im, Jong-In;Yook, Young-Jin
    • Journal of the Korean Ceramic Society
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    • v.43 no.12 s.295
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    • pp.859-864
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    • 2006
  • For the pressure compaction process of the ceramic powder, the green density is very different with both the ceramic body shape and the processing conditions. The density difference cause non-uniform shrinkages and deformations, and make cracks in the sintered ceramics. In this paper, Material properties of the alumina powder mixed with binder and the friction coefficient between the powder and the tool set were determined through the simple compaction experiments: Also the powder flow characteristics were simulated and the green density was analyzed during the powder compaction process with Finite Element Method (FEM). The results show that the density distributions of the green body were improved at the optimized processing condition and both the possibility of the farming crack generation and rho deformation of the sintered Alumina body were reduced.

Design and Construction of the Green Wall System considering Distribution Effect of Earth Pressure by Soil Nail (쏘일네일의 토압분담효과를 고려한 그린월 시스템의 설계 및 시공)

  • Park, Si-Sam;Cho, Sung-Han
    • Journal of the Korean Geosynthetics Society
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    • v.5 no.3
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    • pp.1-7
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    • 2006
  • The Green Wall system, developed in Austria early 1960, is one of segmental concrete crib type earth retaining wall. Green wall is constructed as procedures that lay the front stretchers, rear stretchers and headers then making a rigid body through harden filled soil of interior cell. Green wall has pro-environmental advantages that able to grow grass in front space of stretchers and decrease cutting ground. In Europe, Green wall used without other reinforcement method. However, green wall used with other reinforcement method like a soil nailing because of environmental problem. This study was performed to introduce the design case by 'Two-Body Translation mechanism' to be able to consider distribution of earth pressure in the soil nailing when designing the green wall using soil nailing system. Also, this study attempts to evaluate the earth pressure change when advanced soil nailing system is constructed using $FLAC^{2D}$ ver. 3.30 program and 'Two-Body Translation mechanism'.

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Effects of Green Gram Extract on Skin Lesion and Histopathological Changes in Mice with Contact Dermatitis (녹두 추출물이 생쥐에 유발된 접촉피부염의 피부 증상과 조직병리학적 소견에 미치는 영향)

  • Jang, Seonkyung;Kang, Yoonhyoung;Oh, Seongyeop;Kang, Yuntae;Kim, Soyeon;Lyu, Ji-Hyo;Kim, Hyungwoo
    • The Korea Journal of Herbology
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    • v.37 no.1
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    • pp.11-18
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    • 2022
  • Objectives : Green gram (mung bean) has a cold nature and has been known to detoxify against various side effects that belong to hot in nature. In particular, since it has the effect of detoxifying fever and detoxification to treat swelling, it was also used externally to treat febrile dermatological diseases such as erysipelas and rubella. This study was designed to determine whether green gram exhibits anti-inflammatory effects on contact dermatitis in mice. Methods : We investigated the effects of green gram extract (70% ethanol extract) on skin lesion, skin thickness and weights, melanin and erythema index and spleen body weight ratio in mice with contact dermatitis induced by repeated application of 1-Fluoro-2,4-dinitrobenzene. Results : Topical application of green gram extract ameliorates skin lesions of contact dermatitis such as scale and roughness induces by 1-Fluoro-2,4-dinitrobenzene. green gram extract also suppressed enlargement of skin thicknesses and weights significantly. In addition, green gram extract treatment also lowered erythema index significantly compared to those in the control group. In the histopathological observation, green gram extract prevented epidermal hyperplasia and hyperkeratosis in inflamed tissues. Finally, green gram extract did not affect changes in body weights and the spleen body weight ratio, unlike dexamethasone, which significantly prevented body weight gain and lowered the spleen body weight ratio. Conclusions : These results imply that green gram, which is known to have a detoxifying effect in Korean medicine, can be used in the treatment of contact dermatitis.

Correlation of the Green Microstructure of ZrO2 with the Colloid/Interface Variables (Zirconia성형체의 미세구조와 콜로이드/계면변수와의 상관관계에 대한 분석)

  • 장현명;한규호;이기강;정한남
    • Journal of the Korean Ceramic Society
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    • v.27 no.1
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    • pp.91-101
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    • 1990
  • The green microstructure and sintering behavior of ZrO2 were analyzed in terms of kinetic stability (measured by the stability ratio ; W) and interfacial characteristics of colloidal suspension. Green density and the most frequent pore radius(MFPR) of green body were directly correlated with the stability ratio. These observations were explained using a concept of the critical stability ratio(Wc) and the potential energy of two interacting particles in colloidal suspension. Analysis of the data also indicates that the potential energy barrier between two interacting colloid particles should be higher than its critical value for a fabrication of ZrO2 green body with dense and uniform microstructure. Besides, we have successfully applied a concept of the donoracceptor interaction to increase the kinetic stability of ZrO2 slip and density of green body.

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Microstructures and Drying of the Alumina Green Body by the Gel-Casting Method (Gel-Casting으로 제조한 알루미나 성형체의 건조와 미세구조)

  • 오창준;이홍림
    • Journal of the Korean Ceramic Society
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    • v.31 no.12
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    • pp.1467-1474
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    • 1994
  • The effects of the dispersion, drying, and binder burning-out on the green-microstructures of gelcasted alumina were studied. The slip consisting of 55 vol% alumina powder and 5 wt% organic materials was well-dispersed by adding 0.28 wt% polyelectrolyte polymer. Green bodies were dried at >85% relative humidity at room temperature. Green-microstructures were observed to be depended on the heating rate during binder burnout. Constant drying rate was not observed in drying process of gelcasted alumina. Sintered body showed its relative density higher than 99% when it was sintered at 1$600^{\circ}C$ for 2 hours.

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Effects of green tea or $Sasa$ $quelpaertensis$ bamboo leaves on plasma and liver lipids, erythrocyte Na efflux, and platelet aggregation in ovariectomized rats

  • Ryou, Sung-Hee;Kang, Min-Sook;Kim, Kyu-Il;Kang, Young-Hee;Kang, Jung-Sook
    • Nutrition Research and Practice
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    • v.6 no.2
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    • pp.106-112
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    • 2012
  • This study was conducted to investigate the effects of $Sasa$ $quelpaertensis$ bamboo and green tea on plasma and liver lipids, platelet aggregation, and erythrocyte membrane Na channels in ovariectomized (OVX) rats. Thirty female rats were OVX, and ten female rats were sham-operated at the age of 6 weeks. The rats were divided into four groups at the age of 10 weeks and fed the experiment diets: sham-control, OVX-control, OVX-bamboo leaves (10%), or OVX-green tea leaves (10%) for four weeks. Final body weight increased significantly in the OVX groups compared with that in the sham-control, whereas body weight in the OVX-green tea group decreased significantly compared with that in the OVX-control ($P$ < 0.01). High density lipoprotein (HDL)-cholesterol level decreased in all OVX groups compared with that in the sham-control rats ($P$ < 0.05) but without a difference in plasma total cholesterol. Plasma triglycerides in the OVX-green tea group were significantly lower than those in the sham-control or OVX-control group ($P$ < 0.05). Liver triglycerides increased significantly in the OVX-control compared with those in the sham-control ($P$ < 0.01) but decreased significantly in the OVX-green tea group compared with those in the OVX-control or OVX-bamboo group ($P$ < 0.01). Platelet aggregation in both maximum and initial slope tended to be lower in all OVX rats compared with that in the sham-control rats but was not significantly different. Na-K ATPase tended to increase and Na-K cotransport tended to decrease following ovariectomy. Na-K ATPase decreased significantly in the OVX-green tea group compared with that in the OVX-control group ($P$ < 0.01), and Na-K cotransport increased significantly in the OVX-bamboo and OVX-green tea groups compared with that in the OVX-control ($P$ < 0.05). Femoral bone mineral density tended to be lower in OVX rats than that in the sham-control, whereas the green tea and bamboo leaves groups recovered bone density to some extent. The results show that ovariectomy caused an increase in body weight and liver triglycerides, and that green tea was effective for lowering body weight and triglycerides in OVX rats. Ovariectomy induced an increase in Na efflux via Na-K ATPase and a decrease in Na efflux via Na-K cotransport. Furthermore, consumption of green tea and bamboo leaves affected Na efflux channels, controlling electrolyte and body water balance.

Development of Night Vision Imaging System Green A Compatible LED for Avionic Applications (항공전자 응용을 위한 NVIS (Night Vision Imaging System) Green A 호환 LED 개발)

  • Kim, Tae Hoon;Yu, Chang Han;Yoon, Hyeon Ju;Kim, Min Pyung;Yoon, Ho Shin
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.4
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    • pp.1-5
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    • 2020
  • By adapting black body leadflame and thin film type Green A filter, we successfully demonstrated night vision imaging system (NVIS) Green A compatible LED. Fabricated NVIS compatible LEDs show small form factor compared to that of commercialized NVIS compatible LED. Especially, NVIS radiance and chromaticity of MIL-STD-3009 specification can be satisfied simultaneously and easily by controlling the color temperature of the white LED as well as the concentration of the Green A dye and the thickness of the Green A filter. The optimal dye concentration of the NVIS Green A filter is expected to be about 1 wt%. The results of this study are expected to contribute to miniaturization, weight reduction and localization of avionic display and lighting devices.

Effect of the Forming Condition on Flexural Strength of Green and Sintered Bodies of Tungsten Carbide for Cutting Tool (절삭공구용 초경합금의 성형체 및 소결체의 강도에 미치는 성형조건의 영향)

  • 이재우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.796-799
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    • 2004
  • The effects of forming presure, organic binder content and moisture on flexural strength were investigated. As moisture content increased in the granules during compaction, the density and strength of the green body were increased. Green strengths were found to improve more strongly with increasing forming pressure in the case of using the granules of higher organic content. The sintered strength was the highest with the organic content of 0.2wt% under all forming pressures.

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