• Title/Summary/Keyword: green density

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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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Fabrication and Characteristics of Low Temperature Firing Substrate by Tape Casting in Fluormica System (Tape Casting에 의한 fluormica계 제조 및 특성 저온 소결 기판의 제조 및 특성)

  • 박대현;최정헌;강원호;김병익
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.673-676
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    • 1999
  • We fabricated green sheet by tape casting method with fluormica glass-ceramic powders for fabrication of low temperature co-firing substrate. After ball milling with organic additives, we investigated green strength and density of green sheets which were casted by doctor blade machine. Green sheets were sintered at 700 ~ 1,00$0^{\circ}C$ for 1 ~3hrs. Microstructure, linear shrinkage and dielectric constant of substrates were surveyed.

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Numerical Simulation of Die Compaction: Case Studies and Guidelines

  • Coube, Olivier
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.185-186
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    • 2006
  • Numerical Simulation of powder die pressing is conducted on Case Study geometry. Influence of fill density distribution and punch kinematics upon green density distribution and punch loading are studied and discussed. Deviations in punch kinematics due to punch deflection influence the most the results in term of density and force.

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Comparative Analysis of Anion Concentration by the Type of Roadside Buffer Green (가로변 완충녹지의 조성유형에 따른 음이온 농도 비교 분석)

  • Yoon, Yong-Han;Joo, Chang-Hun;Park, Hun;Kim, Jeong-Ho
    • Journal of Environmental Science International
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    • v.23 no.7
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    • pp.1339-1347
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    • 2014
  • This study were performed on roadside buffer green in Songpa-dong, Songpa-gu, Seoul in order to analyze the anion concentration according to the type of composition of roadside buffer green. Buffer green separating the physical structure of the measurement points and measurement locations were separated by roadside, green interior, the other side of the road. planting density and deposit of trees per each buffer green was measured in the order of mounding type> slope type> the plain type. If the measured temperature of the location-specific weather elements roadside> inside> the other side of the road in order of measurement and the temperature is lowered farther away from the road. If the relative humidity of the road on the other side> inside> the roadside in order to measure and this is the opposite of the temperature tendency. According to physical structure reduction of the temperature on the other side of the road and roadside in order of mounding type> the plain type> slope type was measured. As a result of measuring a anion therefore concentration of the anion inside of melt is in order of mounding type> the plain type> slope type, tended to match the melt characteristics. According to measured positions anion concentration is in the order of the other side of the road> inside> the roadside was measured. As a result of correlation analysis, in the case of measurement location-specific weather and anions the temperature is positive correlation, relative humidity is negative correlation and that's results of previous studies were supported.

Shaping and Sintering of $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$ System powders by Slurry Process (Slurr법에 의한 $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$계 미분말의 성형과 소결성)

  • 김복희;최석홍
    • Journal of the Korean Ceramic Society
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    • v.33 no.11
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    • pp.1267-1275
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    • 1996
  • Green sheet was prepared by tape casting in the composition of (1-x)Pb(Mg1/3Nb2/3)O3-PbTiO3 system using Pb(Mg1/3Nb2/3)O3 and PbTiO3 synthesized with PbO, Nb2O5 MgO and TiO2 The densest green sheet was obtained in the weight ratio 70:30 of powder to binder. Green sheet wasmultilayered in metal mould and formed into lamination at 7$0^{\circ}C$, 300kg/cm2 The lamination was sintered at 110$0^{\circ}C$ 2hr, Dielectric constant and Curie temperature of disc type sintered body was highered with increasing the amount of PbTiO3 and was in the range of 19000-21000, -7~45$^{\circ}C$ respectively. Green and sintered relative density of lamination was 61% and 95% respectively.

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The Effect of Cultural Factors on Anther Culture in Spring Wheat (Triticum aestivum)

  • Kang, Tae-Jin;Yang, Deok-Chun
    • Plant Resources
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    • v.6 no.2
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    • pp.153-158
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    • 2003
  • Effects of shaking, medium consistency and anther density on polyhaploid production in two wheat cultivars, Pavon and Chris, were studied using a modified 85D12 medium. Pavon produced more calli in shaking and more albino plants tban Chris. However, Chris produced threefold more green plants than Pavon in non-shaking treatment. More calli and green plants were derived from non-shaking treatment than those from shaking treatment. Anthers were cultured on both liquid and semi-solid 85D12 media, using two anther densities, 48 and 96 anthers per plate. Although Pavon generally produced more calli and albino plants than Chris, Chris produced more green plants than Pavon. More green plants were derived from semi-solid medium than those from liquid medium. A factor that may affect plant regeneration from anthers is the length of time on initiation medium. Most of the calli for both genotypes were transferred during the first two time periods. Fertility, as measured by seed set, was determined for all surviving regenerated plants. About 24% of Chris and Pavon anther-derived green plants in the experiment of medium consistency and anther density produced seed.

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Curing Behavior of Phenolic Resin with Humid Atmosphere on The Porous $ZrO_2$ ceramics

  • Yun, Sang-Hyeon;Kim, Jang-Hun;Kim, Ju-Yeong;Lee, Jun-Tae;Lee, Hui-Su
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.57.1-57.1
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    • 2011
  • The effects of relative humidity on the properties of the porous $ZrO_2$ ceramics were investigated in terms of the curing behavior of phenolic resin as a binder. The $ZrO_2$ powders containing 5wt% of phenolic resin were conditioned in a consistent chamber condition at a temperature of $50^{\circ}C$ and different humidity levels (25, 50, 75, and 95%) for 1 h. The exposure of humid atmosphere caused changes of density and microstructure in the green bodies. The higher level the powders were exposed to the humid atmosphere, the lower green density was obtained and the more irregular microstructure was observed due to aggregation by the curing of phenolic resin. After firing, the porosity of specimens has risen from 35.7% to 38.1% and Young's modulus has declined in response to the variation of green density. These results could be explained by the degree of resin cure which was associated with the area under the exothermic peak enclosed by a baseline of DSC thermogram curve. Also, the curing behavior of phenolic resin according to relative humidity has been confirmed by decrease of ether groups which have interacted with the phenolic-OH group and the hexamine as a curing agent. Consequently, it could be demonstrated that increase the relative humidity during fabrication of porous $ZrO_2$ diminished the compaction and properties of specimens after firing owing to curing of phenolic resin.

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A Study on the Color and Texture of Fashion Fabrics (패션 소재의 색채 이미지와 질감에 관한 연구)

  • 추선형;김영인
    • Journal of the Korean Society of Clothing and Textiles
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    • v.26 no.2
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    • pp.193-204
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    • 2002
  • Many fashion forecasting companies propose the fashion colors in every season. Modern fashion consumer respond to fashionable trends with utmost sensitivity. Therefore to satisfy the consumer with an trendy image, the fashion design must be found first, as image matters, followed by an analysis of each design element's effect on the total image composition. In previous studies of fashion image, has been discussed the positive correlation between fashion design elements of color, fabric, and form as the central issue. In this thesis, two of the fashion design elements, color and fabric are simultaneously considered to classify the image of fabric in fashion. For the color variables, 10 hues are selected from Munsell's system of color notation, and 12 tones from PCCS color notation., which are currently used in the domestic fashion industry. Texture variables used in this survey are classified by luster, prominence-depression of surface, thickness, and density of fabric. Graduate students from 20 to 50 years old and the specialists in fashion companies participated in the survey. The results of this survey are as follows: 1. The fashion fabric image is classified as 5 main images: 'elegant', 'comfortable', 'characteristic', 'light'and 'simple'. 2. The influence of hue, tone and texture is significant to the fashion fabric image. Following colors, yellow-red, red hues and light grayish, dark grayish tones convey the elegant image. The texture property for the elegant image is luster, thin and low density. Properties of fabric conveying the comfortable image are yellow-red and green-yellow hue, soft, light tones, matte and high density. Furthermore, hue turned out to be a insignificant variables for the unique image, whereas dark grayish, grayish tone, luster and prominent texture convey a unique image. For light image, properties of fabric are blue-green, purple hues, light, bright tones with thin, low density texture. Properties of fabric conveying the simple image are blue-green, purple-blue, green-yellow hues, and strong, vivid tones, with luster and flat texture.

Study on the Electrochemical Characteristics of Lithium Ion Doping to Cathode for the Lithium Ion Capacitor (리튬이온 커패시터의 음극도핑 및 전기화학특성 연구)

  • CHOI, SEONGUK;PARK, DONGJUN;HWANG, GABJIN;RYU, CHEOLHWI
    • Journal of Hydrogen and New Energy
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    • v.26 no.5
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    • pp.416-422
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    • 2015
  • Lithium Ion capacitor (LIC) is a new storage device which combines high power density and high energy density compared to conventional supercapacitors. LIC is capable of storing approximately 5.10 times more energy than conventional EDLCs and also have the benefits of high power and long cycle-life. In this study, LICs are assembled with activated carbon (AC) cathode and pre-doped graphite anode. Cathode material of natural graphite and artificial graphite kinds of MAGE-E3 was selected as the experiment proceeds. Super-P as a conductive agent and PTFE was used as binder, with the graphite: conductive agent: binder of 85: 10: 5 ratio of the negative electrode was prepared. Lithium doping condition of current density of $2mA/cm^2$ to $1mA/cm^2$, and was conducted by varying the doping. Results Analysis of Inductively Coupled Plasma Spectrometer (ICP) was used and a $1mA/cm^2$ current density, $2mA/cm^2$, when more than 1.5% of lithium ions was confirmed that contained. In addition, lithium ion doping to 0.005 V at 10, 20 and $30^{\circ}C$ temperature varying the voltage variation was confirmed, $20^{\circ}C$ cell from the low internal resistance of $4.9{\Omega}$ was confirmed.

The Region of Positivity and Unimodality in the Truncated Series of a Nonparametric Kernel Density Estimator

  • Gupta, A.K.;Im, B.K.K.
    • Journal of the Korean Statistical Society
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    • v.10
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    • pp.140-144
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    • 1981
  • This paper approximates to a kernel density estimate by a truncated series of expansion involving Hermite polynomials, since this could ease the computing burden involved in the kernel-based density estimation. However, this truncated series may give a multimodal estimate when we are estiamting unimodal density. In this paper we will show a way to insure the truncated series to be positive and unimodal so that the approximation to a kernel density estimator would be maeningful.

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