• 제목/요약/키워드: MgB2

검색결과 4,795건 처리시간 0.034초

몇몇 허브식물의 생육에 미치는 B-9과 Uniconazole 처리효과 (Effect of B-9 and Uniconazole on the Growth of Mentha piperita, Origanum vulgare L., and Thymus vulgaris L.)

  • 이정화;문윤자;박기배;허무룡;박중춘
    • 원예과학기술지
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    • 제17권2호
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    • pp.131-133
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    • 1999
  • 식물생장억제제 처리시 대조구에 비하여 초장이 짧아지는 것으로 나타났으며 uniconazole 처리가 B-9 처리보다 초장억제에 더욱 효과적이었으나 Thymus vulgaris 2,500mg/L B-9 처리시는 uniconazole 처리보다 초장이 짧은 결과를 보였다. 5,000mg/L B-9처리시 공시한 3종 모두의 삽수가 고사하였다. 신초수는 대조구에서 가장 많이 발생하였으며 B-9 처리시는 uniconazole 처리에 비하여 신초발생이 많았다. 잎에 대한 생장억제제의 처리 효과는 공시식물 모두 유의차가 적었으며 절간장은 초장과 같은 결과를 나타내었다. Mentha piperita, Origanum vulgare와 Thymus vulgaris 지하부 생육은 B-9이나 uniconazole에 의해 현저하게 영향 받지 않았다.

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B2O3의 첨가에 따른 저온 소결기판용 LiO2-MgO-MgF2-SiO2계 유리의 결정화에 관 한 연구 (The Crystallization of LiO2-MgO-MgF2-SiO2 Glass System by B2O3 addition)

  • 김병일
    • 마이크로전자및패키징학회지
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    • 제5권1호
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    • pp.31-38
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    • 1998
  • 저온소결기판용 Glass-ceramics를 제조하기 위해 LiO2-MgO-MgF2-SiO2계 조성에 서 B2O3첨가가 결정화 특성 및 물성에 미치는 영향을 고찰하였다. 145$0^{\circ}C$에서용융하여 제조 한 모유리의 핵형성 온도와 결정화 온도를 결정하기 위해 TMA와 DTA분석을 실시하였다. 결정화시킨 유리의 결정상과 미세구조를 관찰하기 위하여 XRD와 SEM관찰을 실시하였다. Water swelling을 통해 Glass-ceramics powder를 제조하였으며 제조한 powder의 평균입자 크기는 8.32$\mu$m였다.

B$_2$O$_3$의 첨가에 따른 저온 소결기판용 $Li_2O-MgO-MgF_2-SiO_2$ (The Crystallization of $Li_2O-MgO-MgF_2-SiO_2$ Glass System by $B_2O_3$ addition)

  • 박대현;강원호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1997년도 추계학술대회 논문집
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    • pp.39-43
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    • 1997
  • Effects of B$_2$O$_3$ addition in the Li$_2$O-MgO-MgF$_2$-SiO$_2$g1ass system were investigated in order to make glass-ceramics for low temperature firing substrate. Base glass was made by melting at 145$0^{\circ}C$ . This glass was analyzed by THA and DTA to settle nucleation and crystallization temperature. After crystallization. crystal phase and microstructure were absorvated by XRD and SEM. Glass powders were made by water swelling method. Average particle size was 5.44${\mu}{\textrm}{m}$

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HPLC로 표준화한 가미삼황산(加味三黃散) 분획물(SH-21-B)의 랫드에 대한 단회경구투여독성시험 (Acute Oral Toxicity Study of Standardized Herbal Preparations(Gami-Samhwang-San, SH-21-B) in Rats)

  • 유영법;김선형;윤유식
    • Toxicological Research
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    • 제21권3호
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    • pp.255-261
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    • 2005
  • Gami-Samhwang-San, a herbal prescription for obesity treatment, is composed of seven crude herbs such as Rehmanniae Radix Preparata, Ephedrae Herba, Scutellariae Radix, Acori Gramineri Rhizoma, Polygalae Radix, Typhae Pollen, Armeniacae Semen, Menthae Herba. In this study, marker substances in n-butanol fraction (SH-21-B) from Gami-Samhwang-San were analyzed by high performance liquid chromatography (HPLC) and acute toxicity of standardized SH-21-B was evaluated by good laboratory practices (GLP) guideline of Korea Food and Drug Administration. Therefore we confirmed that there were baicalin of 15.92%, amygdalin of 6.57% and ephedrine of 2.49% in SH-21-B. SH-21-B was administered in rats at dose of 0 mg/kg, 2,000 mg/kg, and 5,000mg/kg. Clinical signs of both sexes of rats were observed daily for 14 days after single oral administration. Two female rats one administered at 2,000 mg/kg and the other administered at 5,000 mg/kg, died, but no dead animal was observed among male rats. Therefore $LD_{50}$ in the female rat is observed to be 8,710 mg/kg, and MLD (Minimun Lethal Dose) of the male rat is observed to be more than 5,000 mg/kg.

마그네슘과 글리세린 처리한 붕소 분말로 합성한 Mg(B1-xCx)2의 초전도 특성 (Superconducting Properties of Mg(B1-xCx)2 Bulk Synthesized Using Magnesium and Glycerin-treated Boron Powder)

  • 김이정;전병혁;박순동;탄카이신;김봉구;손재민;김찬중
    • 한국분말재료학회지
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    • 제15권3호
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    • pp.182-187
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    • 2008
  • Carbon was known to be one of effective additives which can improve the flux pinning of $MgB_2$ at high magnetic fields. In this study, glycerin $(C_3H_8O_3)$ was selected as a chemical carbon source for the improvement of critical current density of $MgB_2$. In order to replace some of boron atoms by carbon atoms, the boron powder was heat-treated with liquid glycerin. The glycerin-treated boron powder was mixed with an appropriate amount of magnesium powder to $MgB_2$ composition and the powder pallets were heat treated at $650^{\circ}C\;and\;900^{\circ}C$ for 30 min in a flowing argon gas. It was found that the superconducting transition temperature $(T_c)$ of $Mg(B_{1-x}C_x)_2$ prepared using glycerin-treated boron powder was 36.6 K, which is slightly smaller than $T_c$(37.1 K) of undoped $MgB_2$. The critical current density $(J_c)$ of $Mg(B_{1-x}C_x)_2$ was higher than that of undoped $MgB_2$ and the $T_c$ improvement effect was more remarkable at higher magnetic fields. The $T_c$, decrease and $J_c$ increase associated with the glycerin treatment for boron powder was explained in terms of the carbon substitution to boron site.

흰쥐의 항염증 및 진통작용에 대한 Glucosamine Hydrochloride와 Taurine 및 그 혼합 투여시의 효과 (Effects of Glucosamine Hydrochloride, Taurine and Their Combined Administration on Anti-inflammatory and Analgesic Action in Rats)

  • 김옥경
    • 한국식품영양과학회지
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    • 제28권5호
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    • pp.1113-1123
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    • 1999
  • The purpose of this study was to see the effect of anti inflammatory and analgesic action of the glucosamine hydrochloride(GA HCl) or taurine. Male Sprague Dawley rats(100~250g) and ICR mice(20 ~30g) were used. Experimental groups were divided into seven groups, one control group given as saline and six groups given as oral administration of GA HCl or taurine; GA HCl 250mg/kg, b.w group, taurine 250mg/kg, b.w group, GA HCl 250mg/kg, b.w+taurine 250mg/kg, b.w group, GA HCl 500mg/kg, b.w group, taurine 500mg/kg, b.w group, GA HCl 500mg/kg, b.w+taurine 500mg/kg, b.w group. Carrageenan induced edema test were shown to be significantly inhibited in the GA HCl 250mg/kg group and taurine 250mg/kg group compared to the control group, but the GA HCl 500mg/kg+taurine 500mg/kg group were significantly inhibited than the control group. Capillary permeability test were shown to be sig nificantly inhibited in the taurine 500mg/kg group, but the GA HCl 500mg/kg+taurine 500mg/kg group were significantly inhibited than the control group. Leucocyte emigration test were shown to be significantly inhibited in the GA HCl 250mg/kg+ taurine 250mg/kg group and GA HCl 500mg/kg+taurine 500mg/kg group compared to the control group. Acetic acid, Phenyl p benzoquinone writhing syndrome were shown to be significantly inhibited in the GA HCl 500mg/kg+taurine 500mg/kg group compared to the control group. Inhibitory action against COX 1 and COX 2 were not significantly inhibited in the experimental group. These results suggest that the combined administration of the GA HCl and taurine have potential action in anti inflammatory and analgesic action.

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$MgB_2$ 박막에서의 열적 활성화에 비해 두드러진 볼텍스 유리화 및 열적 요동현상의 연구 (Domination of glassy and fluctuation behavior over thermal activation in vortex state in $MgB_2$ thin film)

  • Kim, Heon-Jung;W. N. Kang;Kim, Hyeong-Jin;Park, Eun-Mi;Kim, Kijoon H. P.
    • Progress in Superconductivity
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    • 제3권1호
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    • pp.23-27
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    • 2001
  • We have investigated the mixed-state magnetoresistance of high quality c-axis-oriented MgB2 thin film for magnetic field from 0.5 T to 5.0 T, applied normal to ab-plane. The temperature dependence of magnetoresistance was well described by vortex glass and fluctuation theories for different temperature regimes. We observed glassy exponent of v(z-1)~3 and upper critical field of $H_{c2}$(0)~35 T, which is consistent with previous data obtained from direct $H_{c2}$(0) measurements. Interestingly, the thermally activated flux flow region was observed to be very narrow, suggesting that the pinning strength of this compound is very strong. This finding is closely related to the recent reports that the bulk pinning is dominant in $MgB_2$and the critical current density of $MgB_2$ thin film is very high, comparable to that of cuprate superconductor. The present results further suggest that $MgB_2$is beneficial to technical applications.ons.

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배양조건이 Bacillus subtilis 융합주의 ${\gamma}-Glutamyltranspeptidase{\;}({\gamma}-GTP)$ 활성에 미치는 영향 (Culture Characteristics on the Activity of ${\gamma}-Glutamyltranspeptidase{\;}({\gamma}-GTP)$ by Bacillus subtilis Fusant)

  • 김관필;김성호;정낙현
    • 한국식품영양과학회지
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    • 제30권3호
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    • pp.395-402
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    • 2001
  • Bacillus subtilis 돌연변이주 중 ${\gamma}-GTP$활성이 높은 SM-2와 SM-10을 융합시켜 획득한 융합주 중 ${\gamma}-GTP$활성이 높은 융합주 FG-21의 배양적 특성을 조사하였다. 융합주 FG-21에 의한 ${\gamma}-GTP$의 생산은 1% glycerol, 1% peptone, 0.1% citric acid, 5 mM $K_2HPO_4$, 1 mM $FeCl_3$, 1 mM $MgCl_2$, 1 mM $NH_4Cl$, pH 7.0의 배지에 의해 $37^{\circ}C$에서 36시간 배양했을 때 621 U/mL으로 최대한 활성을 보였다. 융합주 FG-21이 생산한 biopolymer A가 단백질함량이 38.4%이고 B. subtilis K-1이 생산하는 biopolymer B의 단백질함량은 19.3%로 융합주 FG-21이 생산하는 Biopolymer A보다 함량이 낮았다. 융합주 FG-21의 biopolymer가 모균주의 biopolymer B보다 단백질함량이 높은 것은 상대적으로 높은 ${\gamma}-GTP$활성이 높아서 생성된 PGA가 levan보다 함량이 많기 때문인 것으로 사료된다. 총당함량은 biopolymer A가 58.5%, biopolymer B가 76.5%로 나타났다. 융합주 FG-21과 모균주가 생산하는 biopolymer의 단백질함량과 총당함량비는 융합주 FG-21이 생성한 biopolymer는 38 : 59. 모균주가 생산한 biopolymer B는 19 : 78의 비율이었고 HPLC 분석에 의한 biopolymer A와 B의 fructose함량은 각각 537.7 mg/g biopolymer, 764.4 mg/g biopolymer으로 나타났다. Biopolymer A와 B의 glutamic acid함량은 각각 163.7 mg/g, 94.3 mg/g이었다. Biopolymer A와 B의 fructose와 glutamic acid의 함량비는 각각 78 : 22, 89 : 11의 비로 함유되어 있었다. 따라서 융합주에 의해 생산된 biopolymer는 모균주보다 구성상태가 변화된 biopolymer를 생산한 것으로 판단되어 fusion과 같은 균주개량을 통하여 물질의 구성적, 물질적 변화된 biopolymer를 생산할 수 있을 것이라 사료된다.

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표고버섯을 이용한 조미료의 주요성분에 관한 연구 (A Study on the Composition of Seasoning Using Lentinus edodes.)

  • 차월석;이명렬;조배식;박세영
    • 생명과학회지
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    • 제14권5호
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    • pp.829-833
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    • 2004
  • 표고버섯(IfHDHHS efodes)조미료 중의 조성물질의 성분을 규명하고자 무기질, 구성아미노산, 유리아미노산, 비타민 등을 분석 검토한 결과는 다음과 같았다. 무기질은 Na가 5.04g%로 가장 많이 함유되어 있고, K, Ca, p, Mg, fe, Zn, Mn, Cu의 순으로 함유되어 있었다. 구성 아미노산을 분석한 결과 총 19종의 아미노산을 함유하고 있었고 인체에 필수한 9종의 아미노산을 모두 함유하고 있었으며, glutamic acid가 4.62%로 가장 많았었고 그 다음으로 glysine, leucine, alanine, aspartic acid, lysine, valine, proline 등의 순으로 함유되어 있으며 그 중 필수아미노산의 총함량은 41.78%였다. 또한 유리 아미노산은 20종으로 분석되었으며 glycine, glutamic acid, asparamine, proline, taurine과 aspartic acid, arginine, leucine, threonine과 serine phenylalanine 등의 순으로 함유되어 있으며 총 함유량은 71.9 mg%이었으며 인체 필수아미노산의 총 함유량은 12.80%이었다. 비타민의 경우 괴혈병의 치료제로 많이 알려져 있는 vitamin C가 224.78 mg%로 가장 많고 판토텐산은 159.09 mg%, vitamin B6 15.08 mg%, 나이아신 3.19 mg%, vitamin E 1.51 mg%, 엽산 1.14 mg%, vitamin B$_{l}$ 1.10 mg%, vitamin B$_{2}$ 0.44 mg%, vitamin D$_{3}$ 0.28 mg%, vitamin A 0.15 mg%, vitamin B$_{12}$ 0.04 mg%, vitamin $K_{l}$ 이 0.02 mg%으로 비타민의 총 함유량은 506.82mg%이었다.다.

Characteristics of a Novel Acinetobacter sp. and Its Kinetics in Hexavalent Chromium Bioreduction

  • M., Narayani;K., Vidya Shetty
    • Journal of Microbiology and Biotechnology
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    • 제22권5호
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    • pp.690-698
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    • 2012
  • Cr-B2, a Gram-negative hexavalent chromium [Cr(VI)] reducing bacteria, was isolated from the aerator water of an activated sludge process in the wastewater treatment facility of a dye and pigment based chemical industry. Cr-B2 exhibited a resistance for 1,100 mg/l Cr(VI) and, similarly, resistance against other heavy metal ions such as $Ni^{2+}$ (800 mg/l), $Cu^{2+}$ (600 mg/l), $Pb^{2+}$ (1,100 mg/l), $Cd^{2+}$ (350 mg/l), $ZN^{2+}$ (700 mg/l), and $Fe^{3+}$ (1,000 mg/l), and against selected antibiotics. Cr-B2 was observed to efficiently reduce 200 mg/l Cr(VI) completely in both nutrient and LB media, and could convert Cr(VI) to Cr(III) aerobically. Cr(VI) reduction kinetics followed allosteric enzyme kinetics. The $K_m$ values were found to be 43.11 mg/l for nutrient media and 38.05 mg/l for LB media. $V_{max}$ values of 13.17 mg/l/h and 12.53 mg/l/h were obtained for nutrient media and LB media, respectively, and the cooperativity coefficients (n) were found to be 8.47 and 3.49, respectively, indicating positive cooperativity in both cases. SEM analysis showed the formation of wrinkles and depressions in the cells when exposed to 800 mg/l Cr(VI) concentration. The organism was seen to exhibit pleomorphic behavior. Cr-B2 was identified on the basis of morphological, biochemical, and partial 16S rRNA gene sequencing chracterizations and found to be Acinetobacter sp.