• Title/Summary/Keyword: W-addition

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In-situ Structure Modification of W powder Skeleton and related Cu Infiltration Kinetics in W-Cu (W-Cu 계에서 W 분말골격의 in-situ 구조 변화와 Cu의 용침 kinetics)

  • 이재성
    • Journal of Powder Materials
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    • v.6 no.1
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    • pp.36-41
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    • 1999
  • The present work has attempted to investigate the dependence of Cu infiltration kinetics on in-situ structure modification of W powder skeleton in W-Cu system. In-situ structure modification of W skeleton by addition of 0.3wt%Ni-P eutectic alloy was designed to proceed during heat-up of the W compact for Cu infiltration process. It was found that the Ni-P added W skeleton underwent remarkable stucture change only during heating-up. its structure was composed of large necks of W particles above 0.5 in the ratio of neck to particle size and smooth pore channels. The infiltration experiment showed that the infiltration kinetics for the W-Ni-P followed well the linear relationship of h vs. $t^{1/2}$ the rate constant K of which was in good agreement with the theoretical value. On the other hand, in case of the pure W skeleton a lower K value by 20% than the theoretical one was obatined. Such discrepancy is discussed in terms of skeleton structure induced infiltration mechanics.

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Characterization of a Novel Carbohydrase from Lipomyces starkeyi KSM 22 for Dental Application

  • KIM, DOMAN;SU-JIN RYU;SOO-JIN HEO;DO-WON KIM;HO-SANG KIM
    • Journal of Microbiology and Biotechnology
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    • v.9 no.3
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    • pp.260-264
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    • 1999
  • The combined activities of dextranase and amylase(DXAMase) from Lipomyces starkeyi KSM 22 produced from starch fermentation inhibited or prevented dental plaque formation. The activities were stable in commercial mouthwash products; DXAMase activity retained over 93% of original activity after 6 months at 23℃. We examined the effects of enzyme inhibitors and active ingredients in mouthwash on DXAMase activity. The DXAMase was stable with 0.29%(w/v) EDTA, 20% (v/v) ethanol, 0.05% (w/v) fluoride, and 0.05% (w/v) SDS. Among the active ingredients of mouthwash, sodium benzoate (up to 1 %, w/v) had no inhibitory effect on either dextranase or amylase activity. In the case of cetylpyridinium chloride, the addition of 0.05% (w/v) inhibited 6% of dextranase activity and 13% of amylase activity. Propylene glycol (up to 1%, w/v) showed no inhibitory effect on either enzyme activity. DXAMase (5 IU/㎖) in mouthwash could remove pre-formed films of glucan-bound S. mutans cells. The addition of 0.1 IU/㎖ DXAMase in mouthwash prevented the formation of insoluble-glucan. These in vitro properties of L. starkeyi KSM 22 DXAMase are desirable for its application as a dental plaque control agent.

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A Study of Activated Sintering Mechanism of $UO_2$ Powder by High Temperature X-Ray Diffractometry

  • Lee, Byoung-Whie;Suh, Kyung-Soo
    • Nuclear Engineering and Technology
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    • v.4 no.2
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    • pp.132-136
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    • 1972
  • The mechanism for activated sintering of UO$_2$by an addition of 0.05 w/o TiO$_2$was investigated using a high temperature X-ray diffractometer. The diffraction pattern of UO$_2$pellets was studied in a temperature range from room temperature to 120$0^{\circ}C$ in hydrogen atmosphere. At 120$0^{\circ}C$, the expansion of UO$_2$lattice were 1.448% and 1.354% greater when it was compared with those at room temperature for pellets with and without the 0.05 w/o TiO$_2$addition, respectively-The effect of the TiO$_2$addition is to increase the lattice constant of UO$_2$by 0.094% at 120$0^{\circ}C$. The lattice constant at 120$0^{\circ}C$without the TiO$_2$addition is equal to that at 108$0^{\circ}C$ with the 0.05 w/o TiO$_2$addition. This temperature difference could be well compared with the suppression of sintering temperature by TiO$_2$hat had been observed Previously. It is believed that the increase in lattice expansion due to the TiO$_2$addition would give rise to the activated sintering of UO$_2$by the lattice-expansion-induced-enhancement of self diffusion.

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A Trial for Preparation of Jam using Sea Mustard Stem (미역줄기를 이용한 잼의 제조조건)

  • AHN Chang-Bum;SHIN Tai-Sun;NAM Taik-Soo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.33 no.5
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    • pp.423-430
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    • 2000
  • Preparation of sea mustard stem jam (SMSJ) with addition of commercial ingredients, sucrose, high methoxyl pectin (HM pectin) or low methoxyl pectin (LM pectin), organic acid (or its salt), and synthetic strawberry flavor to sea mustard stem paste was investigated. The sea mustard stem paste was produced by crushing sea mustard stem and homogenizing it with 2.5 times water of sea mustard stem, then followed by filtering ($30{\~}35 mesh$), The effects of those ingredients on the physical properties and the sensory score of SMSJ were evaluated. The SMSJ prepared with combination of $65{\%}$ (w/w) sugar, $1.0{\%}$ (w/w) pectin, and $0.3{\%}$ (w/w) citric acid or with combination of $65{\%}$ (w/w) sugar, $1.0{\%}$ (w/w) U pectin, and $0.08{\%}$ (w/w) calcium lactate, which finally adjusted to $62{\cdot}Brix$, was similar to commercial strawberry or apple jam in gel strength, Addition of over $0.06{\%}$ (v/w) synthetic strawberry flavor to sea mustard stem paste showed a good effect of masking the undesirable sea mustard flavor.

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The Control of Fermentation Conditions of Salted and Fermented Anchovy by Homogenates of Potato, Solanum tuberosum (감자 마쇄물을 이용한 멸치젓갈의 숙성 조절)

  • BYUN Han-Seok;LEE Tae-Gee;YEO Seang-Gyu;PARK Yeung-Beom;KIM Seon-Bong;PARK Yeung-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.27 no.2
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    • pp.121-126
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    • 1994
  • The present study was designed to investigate effects of the addition of potato homogenates on fermentation control of salted anchovy. With the addition of $8\%$ (w/w) potato homogenates(P), amino-N content and pH were maintained at lower values in the muscle and juice of salted anchovy during all fermentation periods, And high values in external appearance of the salted and fermented anchovy-body during fermentation period were recorded. Consequently, the suppressing effect on the fermentation of salted anchovy of the addition of $8\%$ (w/w) potato homogenates was proved. As for the factors related to the suppressive effects on fermentation, there was no change in amino-N content, and viable cell counts and pH values were maintained.

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Quality characteristics of sausage added red yeast rice (홍국쌀 첨가 소시지의 품질 특성)

  • Kim, Do-Wan
    • Food Science and Preservation
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    • v.20 no.6
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    • pp.805-809
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    • 2013
  • This study was carried out to investigate the effects and characteristics of sausages with red yeast rice added, particularly the Monascus purpureus KFRI 1134 strains, and to decide the optimal quantity of red yeast rice used. The additional rate of red yeast rice which has been used as a material for reducing nitrite, a coupler in meat products were 0, 1, 3, and 5% (w/w). In terms of the effects of the red yeast rice on the color, texture properties, and sensory characteristics of the sausages, the optimal temperature at which color stability was shown was below $100^{\circ}C$, and the addition of 1% red yeast rice resulted in a distinctly attractive color and increasingly improved the red color in the UV-visual Spectrophotometer analysis. However, the addition of over 1% (w/w) resulted in an unattractive color. The red colors also had strong heat stability. The texture properties and taste of the sausages were not affected by the red yeast rice.

Antioxidative Activity of Ulmi cortex Extract (유백피(Ulmi cortex) 추출물의 항산화 활성)

  • 이경행;전은경;유시영;오만진
    • Food Science and Preservation
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    • v.7 no.4
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    • pp.373-379
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    • 2000
  • The Ulmi corex extract was prepared using various solvents to investigate the availability as a natural antioxidant. The extracts were added to lard emulsion and the antioxidant activities were compared. The extract that had a greater antioxidant activity was fractionized. Then the antioxidant activity and substrate specificity of the fraction were examined and optimum concentration of addition was determined. To observe the antioxidative effect of the fraction in vivo, an inhibition rate of lipid peroxidation from which might be derived was measured using a microsome in rat's liver. Among the extracts of Ulmi cortex, the extract from water had the best antioxidant activity, and the addition of 0.05% (w/w) of ethyl acetate fraction showed similar antioxidant activity to a synthetic antioxidant, butylated hydroxyanisole(BHA). Ethyl acetate fraction (0.05%, w/w) also presented the antioxidative effect in lard, soybean oil, palm oil, and com oil. The inhibition of lipid peroxidation in liver microsome showed feater in the ethyl acetate fraction than caffeic acid in both nonenzymatic peroxidation (Fe$\^$++/ascorbate system) and enzymatic peroxidation (Fe$\^$++/-ADP/NaDPH system).

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Design And Component Performance Analysis of RF System for W-CDMA Receiver (W-CDMA 수신기 RF System 설계 및 부품 성능 분석)

  • 지만구;이규헌;김학선
    • Proceedings of the IEEK Conference
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    • 2000.11a
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    • pp.197-200
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    • 2000
  • In this paper, The RF system of W-CDMA receiver is designed and the performance is analyzed. The linearity characteristic and the noise characteristic are presented in the performance. The linearity characteristic is analyzed by PN and IIP3. The noise characteristic is analyzed by NF. In addition, sweeping of the nonlinear components parameter affecting the linear performance is tested and the most maximal possible parameter to maintain the linear performance is introduced. The transceiver RF system of W-CDMA and cdma2000 is designed and presented adapting the nonlinear parameter introduced.

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