• Title/Summary/Keyword: Powder characteristic

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Microstructure and Processing of Bioactive Ceramic Composites as Dental Implants (치과 임플란트용 bioactive 세라믹 복합재료의 제조와 미세조직)

  • Kim, Bu-Sob
    • Journal of Technologic Dentistry
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    • v.25 no.1
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    • pp.21-28
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    • 2003
  • The purpose of this study was to process bio-active glass ceramic composite, reinforced with sapphire fibers, by hot press. Also to study the interface of the matrix and the sapphire fiber, and the mechanical properties. Glass raw materials melted in Pt crucible at 1300$^{\circ}C$ during 3.5 hours. The melt was crushed in ball mill and then crushed material, ground and sieved to $<40{\beta}{\mu}m$. Sapphire fibers cut (30mm) and aligned. Powder and fibers hot pressed. The micrographs show good bonding between the matrix and the fiber and no porosity in the glass matrix. This means ideal fracture phenomena. Glass is fractured before the fiber. This is indication of good fracture strength. EDXS showing aluminum rich phase and crystalline phase. Bright field image of the matrix showing crystalline phase. Also diffraction pattern of TEM showing the crystalline phase and more than one phase. Strength of the samples was determined by 3 point bend testing. Strength of the 10vol% sample was approximately 69MPa, while strength of the control sample is 35MPa. Conclusions through this study as follow: 1. Micrographs show no porosity in the glass matrix and the interface. 2. The interface between the fiber and the glass matrix show no gaps. 3. Fracture of the glass indicates characteristic fiber-matrix separation. 4. Presence of crystalline phase at high processing temperature. 5. Sapphire is compatible with bioactive glass.

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Study of Oriental Medicinal Types of Medical Treatment in Children (소아(小兒) 임상상(臨床上) 한약제형(韓藥劑形)에 관(關)한 연구(硏究))

  • Kim Ki-Bong;Kim Jang-Hyun
    • The Journal of Pediatrics of Korean Medicine
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    • v.13 no.2
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    • pp.111-123
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    • 1999
  • In children, flesh and muscle are tender, mental function is feeble, digestion and absorption are weak. Also food, drink and medicine which burden the stomach and bowels must be avoided. Oriental medicines are divided in object of medical treatment into three types, liquid medicine, medicinal powder and pill. In spite of this types, time and effort are spended greatly on children's eating medicine. In this paper, studying general characteristic of oriental medicinal types and effective types of oriental medicine, I can obstain such conclusions. 1. The oriental iense pillow remedy sets at easy, promotes degistion, treats disease of theesporatory organs. 2. The distillation remedy is suited to a chronic disease of children the degistion are ak in. 3. The mother remedy, because medicine is supplied through mother's body, is effective to infant. 4. The external use remedy is suited to skin disease, eye disease and nose disease, and has similar effect to taking liquid medicine. 5. The confectionery remedy is the method which children like greatly, but is the effective method to many children because of technical manufacture.

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Electrochemical determination of hydrogen peroxide using carbon paste biosensor bound with butadiene rubber (부타디엔 고무로 결합된 탄소반죽 바이오센서를 이용한 과산화수소의 전기화학적 정량)

  • Yoon, Kil-Joong
    • Analytical Science and Technology
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    • v.23 no.5
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    • pp.505-510
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    • 2010
  • When polybutadiene dissolved in toluene was a binder of carbon powder, the volatility of solvent just after electrode fabrication assured the mechanical solidity of the carbon paste electrode. This characteristic met the qualifications for practical use of carbon paste electrodes. A new enzyme electrode bound with butadiene rubber was constructed. In order to confirm whether it shows quantitative electrochemical behaviors or not, its electrochemical kinetic parameters, e.g. the symmetry factor, the exchange current density, the capacitance of double layer, the time constant, the maximum current, the Michaelis constant and other factors were investigated. These experimental facts showed that butadiene rubber is a recommendable binder for practical use of a carbon paste electrode.

Formation and Characterization of Green and Blue Phosphor Nano Powders (녹색과 청색 형광체 나노 분말의 합성 및 특성 평가)

  • Kwon, Oh Sung;You, Young Chul;Kim, Sang Min;Kim, Ki Do;Lim, Hyung Sup;Kim, Hee Taik
    • Applied Chemistry for Engineering
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    • v.20 no.5
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    • pp.565-569
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    • 2009
  • Nano-sized green and blue phosphor powders were synthesized by liquid phase method to confirm the size and morphology. By using that process, the particle sizes of green and blue phosphor particles were 80 nm and 60 nm, respectively. The characteristic comparison of $Zn_2SiO_4$ : Mn and BAM : Eu was carried out and as a result, $Zn_2SiO_4$ : Mn powders showed an higher PL performance compared to BAM : Eu.

Synthesis and Characteristic of BaMgAl10O17:Eu2+ Phosphor by SHS (자전연소 합성법을 통한 BaMgAl10O17:Eu2+ PDP용 청색형광체의 합성과 특성)

  • Lee Jong Eun;Kim Byeong Beom;Park Yeong Cheol;Won Chang Whan
    • Korean Journal of Materials Research
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    • v.14 no.12
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    • pp.885-888
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    • 2004
  • $BaMgAl_{10}O_{17}:Eu^{2+}$ for PDP blue phosphor was synthesized using SHS(Self-propagating High temperature Synthesis) method. While Al metal powder was oxidized in this combustion, $Eu_{2}O_3$ was reduced to Eu2+. Therefore the mole ratio of $Al/Al_{2}O_3$ is one of the most important variable of the reaction. When $Al/Al_{2}O_3$ is 2.5/3.75, it has not only appropriate temperature and reaction velocity, but also excellent luminescent property. The sample synthesized in this system has similar characteristics comparing to sample using conventional solid-state reaction.

A Study on the Historical Research of Indigo Clothing Gifts of Early Joseon -Focusing on the Po and Ieom of King Seongjong's Reign- (조선 전기 아청사여복식(鴉靑賜與服飾)의 고증적 분석 -성종 재위기의 포 류와 이엄을 중심으로-)

  • Choi, Jeong
    • Journal of the Korean Society of Clothing and Textiles
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    • v.44 no.1
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    • pp.107-125
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    • 2020
  • Indigo [鴉靑] was used as a symbolic color in 15th century diplomacy. This study reinforces the historical research for characteristic and shapes of indigo colored royal clothing gift in King Seongjong's reign with a focus on po [袍] and ieom [耳掩]. Clothing made of fur that was combined with satin damask, silk gossamer [綃] were frequent gift, and a sable coat was a symbol of high-ranking clothes. Another clothing's materials were satin damask, sheer fabric gauze [羅], cotton, tabby with silk and ramie [紵絲]. The indigo color of King Seongjong's reign was recommended not for luxury. Historical research factors for indigo clothing gift were extracted from noblemen's relics. Danryeong and jigryeong are shaped of narrow sleeves and trapezoid gusset pleated in and out. Sable coat can consist of satin damask outshell, sable lining, and double oblique collar. Heohyung are presumed types of short sleeved fur vests. Ieom can be reconstructed with an indigo fabric outshell and sufficient fur. Dapho has gusset pleated wide and narrow. As additional gifts, the shapes of yoseon-cheopri and cheopri were analyzed. We selected a commercial fabric similar to relics and an indigo powder dyeing method to remedy a lack of traditional material. The reconstructed data were presented as flat drawings and samples.

Quality Characteristics of Cookies Containing Powder of Extracts from Angelica gigas Nakai (참당귀 추출물을 첨가한 쿠키의 품질 특성)

  • Moon, Young-Ja;Jang, Soon-Ae
    • The Korean Journal of Food And Nutrition
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    • v.24 no.2
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    • pp.173-179
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    • 2011
  • The principal objective of this study was to develop processed food with the effect of extract from Angelica gigas Nakai by assessing the quality characteristics of cookies. Cookie samples were prepared with shredded extract from Angelica gigas Nakai at varied levels of 0, 1, 3, and 5%. The pH of dough decreased significantly with the added extract from Angelica gigas Nakai and the density increased significantly in the 5% added group(p<0.05). The spread factor decreased significantly as the added extract from Angelica gigas Nakai increased(p<0.05). The Hunter color's L value in cookies significantly decreased and the a, b values in cookies increased(p<0.05). The hardness of cookies significantly increased added extract from Angelica gigas Nakai increased(p<0.05). The acid value and peroxide value were lower in added Angelica gigas Nakai extract groups than in the control group as the storage period of cookies passed. The results of sensory characteristics demonstrated that 1% added Angelica gigas Nakai extract showed the highest degree of preference among all the items of added Angelica gigas Nakai extract(color, odor, taste, hardness, crispness and overall quality) and the added Angelica gigas Nakai extract indicated possibilities for developments of Angelica gigas Nakai extract cookies.

Cu2ZnSnSe4 Thin Films Preparation by Pulsed Laser Deposition Using Powder Compacted Target

  • Kim, Kyoo-Ho;Wibowo, Rachmat Adhi;Alfaruqi, M.Hilmy;Ahn, Jong-Heon
    • Journal of the Korean institute of surface engineering
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    • v.44 no.5
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    • pp.185-189
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    • 2011
  • $Cu_2ZnSnSe_4$ thin films for solar absorber application were prepared by pulsed laser deposition of a synthesized $Cu_2ZnSnSe_4$ compound target. The film's composition revealed that the deposited films possess an identical composition with the target material. Further film compositional control toward a stoichiometric composition was performed by optimizing substrate temperature, deposition time and target rotational speed. At the optimum condition, X-ray diffraction patterns of films showed that the films demonstrated polycrystalline stannite single phase with a high degree of (112) preferred orientation. The absorption coefficient of $Cu_2ZnSnSe_4$ thin films were above 104 cm.1 with a band gap of 1.45 eV. At an optimum condition, films were identified as a p type semiconductor characteristic with a resistivity as low as $10^{-1}{\Omega}cm$ and a carrier concentration in the order of $10^{17}cm^{-3}$.

Industry safety characteristic of Prismatic EDLCs (각형 전기이중층 커패시터의 산업 안전성)

  • 김경민;장인영;강안수
    • Proceedings of the Safety Management and Science Conference
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    • 2004.05a
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    • pp.247-257
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    • 2004
  • Electrodes were fabricated based on activated carbon powder BP-20, conducting agent such as Super P, vapor grown carbon fiber (VGCF) and acetylene black (AB), and the mixed binders of flexible poly(vinylidenefluoridehexafluoropropylene) [P(VdF-co-HFP)] and cross linking dispersion agent of polyvinylpyrrolidone (PVP) to increase mechanical strength. According to impedance measurement of the electrode with the addition of conducting agent, we found that it was possible to charge rapidly by the fast steady-state current convergence due to low equivalent series resistance (AC-ESR, fast charge transfer rate at interface between electrode and electrolyte and low RC time constant. The self-discharge of unit cell showed that diffusion process was controlled by the ion concentration difference of initial electrolyte due to the characteristics of Electric Double Layer Capacitor (EDLC) charged by ion adsorption in the beginning, but this by current leakage through the double-layer at the electrode/electrolyte interface had a minor effect and voltages of curves were remained constant regardless of electrode material. We found that the 2.3V/230F grade EDLC would be applied to industrial safety usage such as uninterrupted power supply (UPS) because of the constant DC-ESR by IR drop regardless of discharge current.

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고상반응법으로 합성된 SrAl_2O_4:Eu^{+2}, Dy^{+3}$ 장잔광 형광체 분말의 빛발광 특성

  • 김병규;유연태;엄기석;이영기
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.3
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    • pp.315-319
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    • 1999
  • Properties of both photoluminescence and long-phosphorescent for Eu, Dy-codoped $SrAl_2O_4$ powder phosphor synthesized by solid reaction method were investigated by PL instrument. Two intense peaks in the emission spectrum measured at 10 K are observed near 450 nm (2.755 eV) and 520 nm (2.384 eV) wavelength, but at 300 K the main peak of 520 nm wavelength is presented. After the removal of light excitation (360 nm), the excellent after-glow characteristic of the phosphorescence were obtained as a result of low decay tiem, although the after-glow intensities of phosphor vary exponentially with the times.

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