• 한국광물학회지
• /
• 제16권3호
• /
• pp.223-232
• /
• 2003

리튬2차전지용 양극소재 개발을 위해 Li[L $i_{x}$M $n_{1-x-y}$C $r_{y}$ ] $O_2$를 공침법(co-p.ecipitation method)을 적용하여 각각 $650^{\circ}C$(CR650)와 8$50^{\circ}C$(CR850)에서 합성하였다. 리트벨트 구조분석 결과 계산의 정밀도를 나타내는 R 지수값을 보면 $R_{exp}$에 대한 $R_{wp}$값( $R_{wp}$/ $R_{exp}$)은 CR650과 CR850의 각각에 대해 19.2%/10.1%과 15.9%/9.76%를 보여주며, $R_{b}$값은 각각 10.9%와 8.54%, 그리고 S(GofF)값은 각각 1.9와 1.6으로 계산되었다. 합성된 양극소재는 공간군 R3m의 층상구조(LiMn $O_2$)가 존재하였으며, 전이금속 층 내의 Mn이 Li로 치환되면서(Li[L $i_{1}$3/M $n_{2}$3/] $O_2$) 단사구조(C2/c)의 거대격자(Superlattice) 구조현상도 관찰되었다. 계산된 단위포는 공간군 R3m, CR650이 a=2.8520(2)$\AA$, c=14.248(2)$\AA$, V=100.40(1)$\AA^3$이며, CR850은 a=2.8504(1)$\AA$, c=14.2371(7)$\AA$, V=100.179(8)$\AA^3$으로 각각 계산되었다. 또한 최종 결정된 화학식은 CR650은 Li[L $i_{0.35}$M $n_{0.56}$C $r_{0.09}$] $O_2$, CR850은 Li[L $i_{0.27}$M $n_{0.61}$C $r_{0.13}$] $O_2$으로 각각 구해졌다.다...다..구해졌다.다...다..

• 전자공학회논문지D
• /
• 제35D권5호
• /
• pp.87-92
• /
• 1998

Ultr shallow p$^{+}$-n junction with Co/Ti bilayer silicidde contact was formed by ion implantation of BF$_{2}$ [energy : (30, 50)keV, dose:($5{\times}10^{14}$, $5{\times}10^{15}$/$\textrm{cm}^2$] onto the n-well Si(100) region and by RTA-silicidation and post annealing of the evaporated Co(120.angs., 170.angs.)/Ti(40~50.angs.) double layer. The sheet resistance of the silicided p$^{+}$ region of the p$^{+}$-n junction formed by BF2 implantation with energy of 30keV and dose of $5{\times}10^{15}$/$\textrm{cm}^2$ and Co/Ti thickness of $120{\AA}$/(40~$50{\AA}$) was about $8{\Omega}$/${\box}$. The junction depth including silicide thickness of about $500{\AA}$ was 0.14${\mu}$. The fabricated p$^{+}$ -n ultra shallow junction depth including silicide thickness of about $500{\AA}$ was 0.14${\mu}$. The fabricated p$^{+}$-n ultra shallow junction with Co/Ti bilayer silicide contact did not show any agglomeration or variation of sheet resistance value after post annealing at $850^{\circ}C$ for 30 minutes. The boron concentration at the epitaxial CoSi$_{2}$/Si interface of the fabricated junction was about 6*10$6{\times}10^{19}$ / $\textrm{cm}^2$./TEX>.

• 한국결정학회지
• /
• 제9권1호
• /
• pp.71-76
• /
• 1998

Bis(ethylenediamine)palladium(II)-Bis(oxalato)palladate(II0, (Pd(C2H8N2)2.Pd(C2O4)2)의 단위 착이온 및 결정의 구조들을 x-선 회절법으로 연구하였다. 이 결정은 단사정계이고, 공간군은 P21/c(군 번호=14)이다. 단위세포는 a=6.959(2), b=13.506(2), c=15.339(2) Å, β=99.94(3)이며, V=1420 Å3, Fw=509.04 Dc=2.380 gcm-3, F(000)=992, μ=25.46 cm-1 Z=4이다. 회절반점들의 세기는 흑연 단색화 장치가 있는 자동 4축 회절기로 얻었으며 Mo-KαX-선 (λ=0.7107 Å)을 사용하였다. 구조분석은 중금속법으로 풀었으며, 최소자승법으로 정밀화하였고, 최종 신뢰도 값들은 1472개의 회절반점에 대하여 R=0.021, Rw=0.030, Rall=0.032 및 S=2.10이었다. 착음이온들은 근본적인 평면구조로써, 이들의 충진구조는 a-축을 따라서 면간거리가 3.41Å인 이중체가 3.44Å 간격으로 배열되어있다.

• 한국자기학회지
• /
• 제14권1호
• /
• pp.7-12
• /
• 2004

F $e_{73.5}$C $u_1$N $b_3$S $i_{15.5}$ $B_{7}$ 비정질 리본 합금을 490∼61$0^{\circ}C$의 온도 범위에서 열처리하고 이를 볼 밀링 하여 얻은 250∼850$\mu\textrm{m}$크기의 자성분말과 5wt%의 세라믹 절연체로 구성된 분말 코아의 자기적 특성에 열처리 온도가 미치는 영향을 조사하였다. 5$50^{\circ}C$에서 1 h동안 열처리하여 직경 11 nm의 $\alpha$-Fe상 나노 결정립 구조로 되었을 때(전기비저항은 110$\mu$Ω$.$cm)가장 높은 실효투자율 및 품질계수를 나타내었으며 그 값은 각각 125와 53이었고, 실효투자율의 경우 약 500 KHz에 이르기까지 일정한 크기를 유지하였다. 그리고 이 열처리 조건에서 230 mW/㎤(f=50 KHz, $B_{m}$ =0.1 T)의 대단히 낮은 자심손실을 나타내었다. 그러나 이 합금의 분말 코아는 종래의 분말 코아 재료(MPP,센더스트 등)에 비해 그리 우수하지 못한 직류 바이어스 특성 특히 저 자장 하에서의 낮은 퍼센트 투자율을 나타내었는데, 이는 종래의 소재와 유사한 투자율을 얻는데 너무 큰 입도의 분말이 필요한 것에 그 원인이 있는 것으로 이해되었다.

• Journal of Preventive Veterinary Medicine
• /
• 제42권4호
• /
• pp.148-156
• /
• 2018

Clostridium perfringens (C. perfringens) may cause diarrhea and enterotoxemia in adult and young livestock, leading to problems in the production and management of farms. Four hundred fecal samples were collected from 25 goat farms located in Gyeongsangbuk-do Province in the Republic of Korea. Sixteen C. perfringens strains were isolates from fecal samples, and the isolates were identified as type A (n=11) and type D (n=5). Additionally, ${\alpha}$- and ${\varepsilon}$-toxin genes were detected in 16 and 5 strains by PCR, respectively, and the enterotoxin gene was presented in 2 strains. The antibiotic susceptibility test was performed using the disk diffusion method and E-test method. In the disk diffusion method, ampicillin (n=16) and chloramphenicol (n=15) were highly susceptible to 16 C. perfringens isolates. In the E-test method, ampicillin, amoxicillin, amoxicillin/clavulanic acid and meropenem were susceptible to more than 14 of 16 C. perfringens isolates. This study indicates that administration of antibiotics such as ampicillin, amoxicillin/clavulanic acid and meropenem can prevent and treat C. perfringens infections in goats.

• 한국자기학회지
• /
• 제5권5호
• /
• pp.874-879
• /
• 1995

고 포화자속밀도를 갖는 Fe미세결정 박막의 자기특성 및 미세구조에 미치는 첨가원소의 영향을 조사하였다. Mo 첨가 박막의 경우, $Fe_{2}Mo$, $Fe_{4}N$, $Fe_{3-2}N$상의 생성으로 연자기 특성이 발현되지 않았다. Ta첨가 박막의 경우, 미세한 TaN, TaC 상이 석출하여 $\alpha$-Fe 결정립을 효과적으로 미세화 시켰으며 Fe 질화물의 생성도 억제되었다. 이에 따라 우수한 연자기 특성이 발현되었으며 FeTaN계 박막은 4000, FeTaC 박막은 2700의 높은 투자율을 나타내었다.

• Macromolecular Research
• /
• 제14권4호
• /
• pp.438-442
• /
• 2006

Novel sulfonated poly(aryl ether ketones) containing benzoxazole were directly synthesized by aromatic nucleophilic polycondensation using various ratios of 2,2'-bi[2-( 4-flurophenyl)benzoxazol-6-yl]hexafluoropropane to sodium 5,5'-carbonylbis(2-fluorobenzenesulfonate). The copolymers were soluble in polar aprotic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide at a relatively high solid composition (>15 wt%) and formed tough, flexible and transparent membranes. The membranes exhibited a degradation temperature of above $290^{\circ}C$. The exact dissolution times of these membranes at $80^{\circ}C$ in Fenton's reagent (3 wt% $H_2O_2$ containing 2 ppm $FeSO_4$) were undetectable, confirming their excellent chemical stability in fuel cell application. The membranes showed a moderate increase in water uptake with respect to increasing temperature. The proton conductivities of the membranes were dependent on the composition and ranged from $1.10{\times}10^{-2}$ to $5.50{\times}10^{-2}Scm^{-1}$ at $80^{\circ}C$ and 95% relative humidity (RH). At $120^{\circ}C$ without externally humidified conditions, the conductivities increased above $10^{-2}Scm^{-1}$ with respect to increasing benzoxazole content, which suggested that the benzoxazole moieties contributed to the proton conduction.

• 한국결정학회지
• /
• 제1권1호
• /
• pp.14-18
• /
• 1990

Econazole nitrate, 1-{2-[(4-chlorophenyl)methoxy]-2-(2,4-dichlorophenyl) ethy1}-1H-imidazole mono-nitrate, C18 H16 CI13 N3 O4의 단위세포 상수는 a=19.337(4) A, b=15.191(5) A c=7.601(3)A, β=91.72(2)μ V=2000.0A3 Do=1.49g/ml Dm=1.47g/ml, M=4.31cm-1 F(000)=912.0, 2T=298K,공간군은 P2₁/C이고 단사 정계이며 Z=4이다. λ=(Mo-Ka)=0.7107 A을 사용한 1330개의 Intensity data에 대해 최종 R값은 0.06이다. Econazole nitrate의 각 세 ring은 각각 평면이며 B,A,C ring순서로 층계를 이루고 있다. 반면에 Econazole의 A와 C ring은 거의 같은 평면에 누워 있으나 B ring 은 거의 같은 평면이며 B,A,C ring순서로 층계를 이루고 있다.반면에 Econazole의 A와 C ring은 거의 같은 평면에 누워있으나 B ring과는 약 60˚의 평면각을 이루고 있다. Nitrate의 O(*3)와 Imidaze의 N(2) 사이의 수소결합은 Econazole slt의 안정화에 기여한다.

• Bulletin of the Korean Chemical Society
• /
• 제16권11호
• /
• pp.1037-1042
• /
• 1995

The reaction of acetophenone 1-ureidoethylidenehydrazones 6 with a mixture of triphenylphosphine, carbon tetrachloride, and triethylamine in dichloromethane provides a general route to 1-(1-phenylethenyl)-5-(N-substituted amino)-1,2,4-triazoles 11 via the electrocyclization of the expected azino carbodiimide intermediates 9 to give the resonance stabilized azomethine imine 10a followed by a proton abstraction from the methyl group by amide anion. However, the same reaction of benzaldehyde 1-ureidoethylidenehydrazones 5 was unsuccessful. Under the same conditions, the reactions of benzaldehyde 1-N-acylureidoethylidenehydrazones 7 or acetophenone 1-N-acylureidoethylidenehydrazones 8 afforded 4H-1,2,4-triazolo[1,5-c][1,3,5]oxadiazines 16 or 17 via the zwitterionic species 15, or a [4+2] intramolecular cycloaddition from the carbodiimide intermediates 14, respectively.

• 한국식생활문화학회지
• /
• 제14권5호
• /
• pp.461-466
• /
• 1999

As a part of investigation to use sardine(Sardinops melanoslicta) more effectively as a food source, this study was undertaken the processing condition of rapid- and low salt-fermented liquefaction of sardine. To prepare rapid fermented products, the chopped whole sardine was added 8% NaCl and then preheating treatment at $40^{\circ}C,\;45^{\circ}C$ and $50^{\circ}C$ in the manufactured fermenter(180L) for 9 hrs, and then fermentation at $33^{\circ}C$ for 90 days. The chemical changes such as amino nitrogen(amino-N), volatile basic nitrogen(VBN), and histamine in the hydrolysates of fermented sardine were analyzed as well as viable cell count and organoleptic evaluation during fermentation to compare the quality between control and preheating samples. During fermenting, the amino-N in the hydrolysates increased rapidly during the first 30 days and slowly thereafter. The highest content of amino-N appeared at 75 days in control sample and $60{\sim}75$ days in preheating samples. The changes of VBN in the hydrolysates increased rapidly during first 15 days in control samples and 30 days in preheating samples. However they were generally low level in preheating samples. Histamine content in the hydrolysates of the control samples increased markedly after 15 days, but preheating samples were generally low level, and then $75{\sim}90$ days of fermentation reached to the maximum which was about $2.0{\sim}3.0$ times lower than that of control samples. As for the organoleptic flavor evaluation, the control and preheating at $40^{\circ}C$ samples were unpleasant odor after 15 and 60 days, respectively. But preheating at $45^{\circ}\;and\;50^{\circ}$ samples were fresh odor after 90 days fermentation.