• Title/Summary/Keyword: MgB2

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Low-temperature Sintering and Microwave Dielectric Properties of the B2O3 and CuO-added Ba(Mg1/3Nb2/3)O3 Ceramics (B2O3와 CuO가 첨가된 Ba(Mg1/3Nb2/3)O3 세라믹스의 저온소결과 마이크로파 유전특성 연구)

  • Lim, Jong-Bong;Son, Jin-Ok;Nahm, Sahn;Yoo, Myong-Jea;Lee, Woo-Sung;Kang, Nam-Kee;Lee, Hwack-Joo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.1
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    • pp.38-42
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    • 2005
  • B$_2$O$_3$ added Ba(Mg$_{1}$3/Nb$_{2}$3/)O$_3$ (BBMN) ceramics were not sintered below 900 $^{\circ}C$. However, when CuO was added to the BBMN ceramic, it was sintered even at 850 $^{\circ}C$. The amount of the $Ba_2$B$_2$O$_{5}$ second phase decreased with the addition of CuO. Therefore, the CuO additive is considered to react with the B$_2$O$_3$ inhibiting the reaction between B$_2$O$_3$ and BaO. Moreover, it is suggested that the solid solution of CuO and B$_2$O$_3$ might be responsible for the decrease of the sintering temperature of the specimens. A dense microstructure without pores was developed with the addition of a small amount of CuO. However, a porous microstructure with large pores was formed when a large amount of CuO was added. The bulk density, the dielectric constant ($\varepsilon$$_{r}$) and the Q-value increased with the addition of CuO but they decreased when a large amount of CuO was added. The variations of those properties are closely related to the variation of the microstructure. The excellent microwave dielectric properties of Qxf = 21500 GHz, $\varepsilon$$_{r}$ = 31 and temperature coefficient of resonance frequency($\tau$$_{f}$) = 21.3 ppm/$^{\circ}C$ were obtained for the Ba(Mg$_{1}$3/Nb$_{2}$3/)O$_3$+2.0 mol%B$_2$O$_3$+10.0 mol%CuO ceramic sintered at 875 $^{\circ}C$ for 2 h.h.2 h.h.

The Quality Comparison of Grape Vinegar by Two Stages Fermentation with Traditional Grape Vinegar (2단계 발효에 의한 포도식초와 재래식 포도식초의 품질 비교)

  • 정용진;이명희;서권일;김주남;이용수
    • Journal of the East Asian Society of Dietary Life
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    • v.8 no.4
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    • pp.462-468
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    • 1998
  • 편이었다. 미량성분으로는 K이 다량으로 존재하였고, 2단계 발효로 제조된 포도식초는 포도양파식초 보다K, Na, Cu함량이 높게 나타났다. ^x Grape vinegar (A) and grape onion vinegar(B) added (3% of onion juice) were produced through two stages of fermentation(alcohol fermentation and acetic acid fermentation) to increase the grape's use. Grape wine which contained 5.6% alcohol was produced on the 3rd day of first stage. Then through the second stages, grape vinegar, of which total acidity was 5.37% was produced. The quality of (A) and ( B) which was produced through the two stages of fermentation was compared with the traditional grape vinegar (C, D) in the market. The content of sugar in (D) was a little higher such as 5.4 $^{\circ}$Brix than others. That of (A) and (B) was 5.13, 4.98 $^{\circ}$Brix respectively. The content of remaining alcohol in (C) was high such as 0.23% comparatively. But there was no remaining alcohol in (A) and (B). The content of acetic acid was 4.3~5.3% as a major organic acid of vinegars. The content of tartaric acid was 340.0 in (A), 315.7 in (B), 322.6 in (C) and 391.7mg% in (D). The content of lactic acid was distinctly high such as 277.4mg% in (D) There were differences such as 9.2~15.5mg% in the content of total free amino acids among grape vinegars. (D) contained 15.5mg% of total free amino acid and (B) also highly such as 12.0mg%. Potassium was high in grape vinegars. The content of potassium, sodium and copper was higher in (A) than (B).

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Effects of Jasmonic Acid on Root Growth and Eleutheroside Accumulation in Adventitious Root Culture of Eleutherococcus koreanum (섬오갈피나무 부정근(不定根) 배양(培養)에서 부정근(不定根)의 생장(生長)과 Eleutheroside 류(類)의 생산(生産)에 미치는 Jasmonic acid 처리(處理)의 영향)

  • An, Jin-Kwon;Park, So-Young;Lee, Wi-Young;Park, Yeongki
    • Journal of Korean Society of Forest Science
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    • v.95 no.1
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    • pp.32-37
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    • 2006
  • The influence of different doses of jasmonic acid on both biomass of adventitious roots and accumulation of secondary metabolite in bioreactor cultures of Eleutherococcus koreanum was studied. The maximum growth (2.9 g Dry Weight/L) of adventitious roots was observed in the absence of jasmonic acid. The biomass of adventitious roots decreased with the increase in jasmonic acid dosage. High level of jasmonic acid efficiently stimulated the production of both eleutheroside B and E. The highest eleutheroside B ($49.0{\mu}g/g\;DW$) was observed at 0.4 mg/L jasmonic acid. Jasmonic acid at 0.2 mg/L led to the maximum accumulation of eleutheroside E ($64.7{\mu}g/g\;DW$). Whereas eleutheroside $E_1$ was maximally $19.0{\mu}g/g\;DW$ accumulated in the absence of jasmonic acid, the total eleutheroside ($259.9{\mu}g/L$) was the highest when 0.01 mg/L jasmonic acid was treated. In this study, the level of eleutheroside B decreased whereas the maximum levels of eleutheroside E and eleutheroside $E_1$ were observed at 10th and 4th day after jasmonic acid treatment.

Effect of Inhibition on Glucosultransferase and Antimicrobial Activity of Polyphenol Fraction of Gallnut and Red Grape Husk (오배자와 적포도과피 폴리페놀 분획물의 항균성 및 Glucosyltransferase 저해효과)

  • 안봉전
    • Food Science and Preservation
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    • v.8 no.2
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    • pp.217-223
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    • 2001
  • The antimicrobial and glucosyltransferase(GTase) inhibition activity were searched for 30 species of various folk drugs and by products of food industry. Among them, two species, gallnut and red grape husk water extracts, were selected for the powerful antimicrobial and GTase inhibition activity. The polyphenol fractions of gallnut and red grape husk were showed very greater antimicrobial activity on both Gram(+) and (-), B. subtilis and E. coli. The minimum antimicrobial activity of gallnut polyphenol fraction were 1.0mg for B. subtilis and 3,0mg for E. coli. Red grape husk was 2.0mg for B. subtilis and 3.0mg for E coli. The polyphenol fractions of gall nut and red grape husk were showed powerful GTase inhibition activity. The concentrations of these fractions for 80% inhibition of GTase activity were 1.08$\times$10$\^$-3/mg/㎖ and 1.08$\times$10$\^$-2/mg/㎖, respectively. The most abundant compound in these fraction seems to be polyphenol derivatives. From these results, we think that the gallnut and the red grape husk polyphenol fraction had more antimicrobial and anti-plaque activities than artificial synthetic preservatives as an economic point of view.

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Synthesis of (Ni,Mg)Al2O4 Ceramic Nano Pigment by a Polymerized Complex Method (착체중합법을 이용한 (Ni,Mg)Al2O4 Cyan 나노 무기안료 합성)

  • Son, Bo-Ram;Yoon, Dea-Ho;Han, Kyu-Sung;Cho, Woo-Suk;Hwang, Kwang-Taek;Kim, Jin-Ho
    • Journal of the Korean Ceramic Society
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    • v.50 no.3
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    • pp.195-200
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    • 2013
  • Here, we report preparation of cyan ceramic nano-pigment for inkjet printing and the Ni substitutional effects on the cyan color. $MgAl_2O_4$ was selected as the crystalline host network for the synthesis of nickel-based cyan ceramic nano-pigments. Various compositions of $Ni_xMg_{1-x}Al_2O_4$ ($0{\leq}x{\leq}1$) powders were prepared using the polymerized complex method. The powder was then preheated at $400^{\circ}C$ for 5 h and finally calcined at $1000^{\circ}C$ for 5 h. XRD patterns of $Ni_xMg_{1-x}Al_2O_4$ showed a single phase of the spinel structure in all the compositions. The particle sizes ranged from 20 to 50 nm in TEM observations. The characteristics of the color tones of $Ni_xMg_{1-x}Al_2O_4$ were analyzed by UV-Visible spectroscopy and CIE $L^*a^*b^*$ measurement. CIE $L^*a^*b^*$ measurement results indicate that the pigment color changes from light cyan to deep cyan due to the decrease of the $a^*$ and $b^*$ values with an increase of an Ni substitutional amount. In addition, the thermal stability and the binding nature of $Ni_xMg_{1-x}Al_2O_4$ are also discussed using TG-DSC and FT-IR results respectively.

Low-Temperature Sintering and Microwave Dielectric Properties of the $B_2O_3-$ and CuO-added $Ba(Mg_{1/3}Nb_{2/3})O_3$ Ceramics ($B_2O_3$ 와 CuO가 첨가된 $Ba(Mg_{1/3}Nb_{2/3})O_3$ 세라믹스의 저온소결과 마이크로파 유전특성 연구)

  • Lim, Jong-Bong;Son, Jin-Ok;Nahm, Sahn;Yu, Myeong-Jae;Lee, Woo-Sung;Kang, Nam-Kee;Lee, Hwack-Joo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.838-841
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    • 2004
  • [ $B_2O_3$ ] added $Ba(Mg_{1/3}Nb_{2/3})O_3$ (BBMN) ceramics were not sintered below $900^{\circ}C$. However, when CuO was added to the BBMN ceramic, it was sintered even at $850^{\circ}C$. The amount of the $Ba_2B_2O_5$ second phase decreased with the addition of CuO. Therefore, the CuO additive is considered to react with the $B_2O_3$ inhibiting the reaction between $B_2O_3$ and BaO. Moreover, it is suggested that the solid solution of CuO and $B_2O_3$ might be responsible for the decrease of the sintering temperature of the specimens. A dense microstructure without pores was developed with the addition of a small amount of CuO. However, a porous microstructure with large pores was formed when a large amount of CuO was added. The bulk density the dielectric constant $({\varepsilon}_r)$ and the Q-value increased with the addition of CuO but they decreased when a large amount of CuO was added. The variations of those properties are closely related to the variation of the microstructure. The excellent microwave dielectric properties of Qxf=21500 GHz, ${\varepsilon}_r=31$ and temperature coefficient of resonance frequency$({\tau}_f)=21.3\;ppm/^{\circ}C$ were obtained for the $Ba(Mg_{1/3}Nb_{2/3})O_3+2.0\;mol%B_2O_3+10.0$ mol%CuO ceramic sintered at $875^{\circ}C$ for 2h.

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Effects of Growth Regulators on Adventitious Root Growth and Eleutherosides and Chlorogenic Acid Accumulation in Air Lift Bioreactor Cultures of Eleutherococcus koreanum (생물반응기 배양에서 생장조절제에 따른 섬오갈피 부정근 증식 및 Eleutheroside와 Chlorogenic Acid 생산)

  • Ahn Jin-Kwon;Park So-Young;Lee Wi-Young;Lee Jeong-Ju
    • Journal of Plant Biotechnology
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    • v.32 no.1
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    • pp.57-61
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    • 2005
  • The influence of different growth regulators on biomass of adventitious roots and secondary metabolites accumulation in bioreactor cultures of Eleutherococcus koreanum was studied. The maximum growth of adventitious roots was observed in the presence of $2.0\;\cal{mg/L}$ IBA (6.7 g DW/L). However the productivity of eleutheroside E was not significantly different among IBA levels. High level of thidiazuron (TDZ) efficiently increased both root growth and secondary metabolites production. Especially when $0.1\;\cal{mg/L}$ TDZ was combined with $3.0\;\cal{mg/L}$ IBA, the highest eleutheroside E accumulation ($3,327{\mu}g/g $DW) was observed. When the same TDZ level was treated in combination with $5.0\;\cal{mg/L}$ IBA, both chlorogrnic acid and eleutheroside B were accumulated to maximum level. In contrast, zeatin remarkably suppressed the accumulation of both eleutheroside B and chlorogenic acid.

The Antioxidant and The Antidiabetic Effects of Ethanol Extract from Biofuntional Foods Prescriptions (기능성 식품 복합처방의 항산화 및 항당뇨 효과)

  • Kim, Jin-Pyo;Chon, In-Ju;Cho, Hyung-Kwon;Ham, In-Hye;Whang, Wan-Kyunn
    • Korean Journal of Pharmacognosy
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    • v.35 no.1 s.136
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    • pp.98-103
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    • 2004
  • To investigate the antioxidant activitys of Biofuntional Foods Prescriptions (BFP), we were measured radical scavenging activity with 1,1-diphenyl-2-picryl-hydrazyl (DPPH) method and anti-lipid peroxidative efficacy on human LDL with thiobarbituric acid reactive substances (TBARS) assay. The DPPH and TBARS assay were revealed that Two BFP had significantly activity when compared to that of contrast drug. The antidiabetic effect of Dicollow-B (Rx B) were investigated in streptozotocin-induced diabetic Spraque-Dawley (SD) rats. When each 100,200 kg/mg fraction of Rx B was administrated. the blood glucose showed 155.7 mg/dl, 124.7 mg/dl and inhibitive activity of the serum total cholesterol showed 67.8 mg/dl, 61.5 mg/dl and the serum triglyce of hyperglycemic rats revealed 66.3 mg/dl, 62.3mg/dl. Those were decreased do dependently when compared with control group. The effect of Rx B on The body weight was not dose-dependently decreased dosedependently when by the administration of 100 mg/kg or 200 mg/kg fractions. But it was dose-dependantly decreased from $22.2{\times}4.9$ g to $18.9{\times}4.4$ g by the administration of 400 mg/kg fraction.

Structural and Dielectric Properties of $Pb(Mg_{1/3}Nb_{2/3})O_3$ Ceramics Substituted by Nd, La, K and Na (Nd, La, K, Na이 치환된 $Pb(Mg_{1/3}Nb_{2/3})O_3$ 세라믹의 구조 및 유전 성질에 관한 연구)

  • Kweon, Sook-Hwa;Park, Hyu-Bum;Kim, Jeong;Hong, Young-Sik;Kim, Si-Joong
    • Journal of the Korean Ceramic Society
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    • v.32 no.7
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    • pp.839-845
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    • 1995
  • The structural and dielectric properties of Pb(Mg1/3Nb2/3)O3 ceramics substituted by Nd3+, La3+, K+ and Na+ were studied over 0~50 at.% substituent content. The 1 : 1 ordering behavior of Mg2+ and Nb5+ ions in the B site sublattice was observed in Nd3+-and La3+-modified compounds. The degree of ordering was increased with Nd3+, La3+ content in the compounds. But K+-or Na+-modified compounds did not exhibit the ordering behavior. This was explained by charge and size effect of A and B site cations and oxygen vacancies. As the mole fractions of substituent increased, the maximum values of dielectric constants were rapidly decreased and the phase transitions were broadened. Phase transition temperature was correlated with the covalency of A-O and B-O bonding.

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A Study on the Quality of Commercial Red Pepper Powder (시판 고춧가루의 품질 특성에 관한 연구)

  • 황성연;안영훈;신길만
    • The Korean Journal of Food And Nutrition
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    • v.14 no.5
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    • pp.418-422
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    • 2001
  • Physicochemical qualities of the different commercial red pepper powder purchased in the market were investigated. In proximate composition of red pepper powder, crude protein contents were not much different from 10.10% to 10.91% but sample Ds crude lipid was the lowest as 8.28% and Cs was the highest as 11.43%. The pH values of red pepper powder were not significantly different. The value of L, a and b of sample C were 46.667, 22.738 and 19.941 respectively but it showed lower ASTA color than sample A and had same tendency with capsanthin. The highest content of capsaicin was sample D as 59.93mg 1100g and sample B was the lowest as 25.87mg/100g. Water activity of the sample A, B, C and D were 0.584, 0.676, 0.526 and 0.568 respectively. Sample A, C and D showed safety against microorganisms but sample B was susceptible to the mold.

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