http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Cu 치환에 따른 Ni-Zn 페라이트의 전자파 흡수 특성
오영우,이선학,김종령,안용운,이승관 경남대학교 신소재연구소 2001 신소재연구 Vol.13 No.-
고상반응법을 이용하여 Ni_0.6-xCuZn_0.4Fe _2O_4(x=0, 0.1, 0.2, 0.3) ferrite 분말을 제조하고 1200℃에서 열처리하여 Cu 치환에 따른 입자변화와 전자파흡수 특성과의 관계를 조사하였다. Ni 자리에 Cu를 0.1mol 치환했을 때는 포화자화값은 큰 변화 없이 일정하였고 우수한 전자파습수능을 나타내었고, 그 이상 첨가 시는 포화자화값과 전자파흡수능은 직선적으로 감소하였다. Ni_0.6-xCuZn_0.4Fe _2O_4 ferrite powder was prepared by the solid-reaction method and sintered at 1200℃ and investigated grain size related with electromagnetic wave absorbing properties were investigated as a function of Cu substitution. The saturation magnetization and electromagnetic wave absorbing efficiency were rarely changed until substitution of Cu 0.1mol into Ni-site, but decreased strongly over 0.1mol Cu,
오관영 여수대학교 2001 論文集 Vol.16 No.-
The purpose of this paper is to suggest a new approach to syllable structure, which can show the whole processes of stress shift and vowel alternations. The approaches I have attempted to show in this paper are three types, these being rule-based, prosodic, and harmonic approaches. However from the comparison of existing methods we can find a few problems in dealing with stress shift and vowel laxing compositely. They dealt with the syllable just partially on the linear, which made us overlook the other important phenomena in the syllable structure. When we look at the stress movement, it causes the vowel lax or tense. Therefore the words related with the phenomena will be dealt with consideration to dual sides. Now this paper will adopt the level approach to show more appropriate explanation than the existing analysis.
오영우,이승관 慶南大學校 附設 工業技術硏究所 1999 硏究論文集 Vol.17 No.-
??의 식에서 x를 0.0∼0.2로 변화시키고, 하소온도를 800 ℃, 소결온도를 1100∼1300℃로 50℃ 간격으로 변화시켜 저항(R)-온도(T)의 특성을 측정하였다. 온도가 증가함에 따라 저항은 지수함수적으로 감소하는 NTC 서미스터의 특성을 나타내었으며, 1200℃에서 소결한 x=0.1 시편에서 가장 양호한 직선성을 나타내었다. 25와 85℃를 기준으로 계산한 Β 상수는 5000에서 7300 [K]의 범위를 나타내었으며, 이는 기존의 Mn-Co-Ni계 서미스터와 같은 범주의 경향을 보였다. 25℃일 때 저항온도계수(α)는 1200℃에서 소결한 x=0.1에서 -5.2 %/℃를 나타내었다. 이로써 본 실험의 조성으로 Mn-Ni-Co 계 서미스터의 대체 재료로서의 가능성을 확인할 수 있었다 ??(x=0.0, 0.025. 0.1. 0.2) for NTC(negative temperature coefficient) thermistor was prepared by calcining at 800℃ and sintering at from 1100 to 1300℃ with 50℃ intervals while x was varied from 0.0 to 0.025, 0.1 and 0.2. The best linear property was obtained in the based specimen sintered at 1200℃ with x=0.1 composition. Thermistor parameter, ??, was in the range of 5000∼7300 [K]. Temperature coefficient of resistance, ??, was -5.2%/℃. The results showed the possibility that Mn-Ni-Co based thermistor could be substituted by the composition used in this study was confirmed.
오영우,이승관,김영근 경남대학교 신소재연구소 1996 論文集 Vol.7 No.-
용융염 합성법으로 Ba-페라이트 미세입자를 합성하기 위하여, 염으로 NaCl과 KCl을 선택하였으며, 이들을 단독 또는 NaCl-KCl의 공정 조성 혼합물로서 시료에 50wt% 첨가하고, 바륨 페라이트의 입자형상을 제어하기 위해 1㏖%의 SiO₂를 첨가 하였다. 보자력 제어를 위한 BaFe_(12-2x)Co_(x)Ti_(x)O_(19) 조성에서 x=0→x=1.0으로 Fe^(3+)를 Co^(3+), Ti^(4+)로 치환량이 증가할수록 H_(c)와 M_(r)값은 큰 폭으로 감소하였고, SiO₂를 1㏖% 첨가한 경우는 첨가하지 않은 경우보다 6각 판상의 c축이 짧아졌고 판상비가 커졌다. In order to synthesize Ba-ferrite fine particles by molten salt method, NaCl and KCl were added to basic composition to 50% by weight, and added 1 mole% of SiO₂to control the shape of the Ba-ferrite particles. H_{c} and M_{r} were decreased when Fe^{3+} was substituted with Co^{2+} and Ti^{4+} from x=0 to x= 1.0 in BaFe_{12-2x}CO_{x}Ti_{x}O_{19}, and 1 mole% SiO₂increased the size but shortened c-axis of hexagonal ferrite.
Photoluminescence과 Conductance 측정을 이용한 자외선 조사된 Ge첨가 다성분계 산화물 유리의 구조변화 관찰
이회관,오영석,강원호 단국대학교 2001 산업기술연구 Vol.2 No.-
Ge-doped multicomponent oxide glasses were prepared by a conventional melting method. The structural change around Ge ions was investigated by using PL(photoluminescence) and conductance(G). After UV irrdiation, the PL intensity decreased and the change were maintained at room temperature, but a photodarkened glass recovered near its original properties when it was heat-treated at 500℃ for several hours. The conductance of the irradiated sample decreased because the disorder in structure was happened by UV irradiation. These results can be explained a structural change were occurred at bonding structure between Ge ions and glass components.
Sweep Co-Distillation법에 의한 산화방지제의 추출법
김재관,황혜정,오문헌,도영숙,윤미혜 한국식품영양학회 1999 韓國食品營養學會誌 Vol.12 No.4
식용유지 중의 산화방지제를 효율적으로 분석하기 위하여 일반적인 용매추출법과 SCD법으로 전처리하여 HPLC법으로 비교 분석하였다. SCD법의 최적조건은 florisil의 활성도와 UNITREX의 온도와 추출시간에 따른 회수율로 분석하였다. 식용유지에 산화방지제를 농도별로 가하여 용매추출법과 SCD법의 회수율을 비교한 결과 용매추출법은 80.4∼102.1%, SCD법은 89.8∼106.4%로 나타났다. Florisil의 활성화에 따르면 2% 수분 첨가시 TBHQ, BHA, BHT는 89.8∼106.4%로 회수율이 가장 높았고, PG는 5% 수분 첨가시 53.9±7.3%의 회수율을 보였다. 회수율은 UNITREX의 210℃에서 20분간 추출하였을 때 가장 높았다. This study was conducted to evaluate the extraction methods for the determination of antioxidants in soybean oil. Recovery rates of various antioxidants in soybean oil showed similar rates as 80.4∼102.1% by solvent/solvent extraction method and 89.8∼106.4% by sweep co-distillation method except 46.6∼61.2% of PG at corresponding spiked concentractions. The maximum recovery rates of antioxidants were obtained when extraction time and extraction temperature used in UNITREX were 20min and 210℃ respectively. In the recovery rates with the activation of florisil, when 2% of water was added to florisil, the highest recovery rates for TBHQ, BHA, BHT were obtained by sweep co-distillation method. Therefore, sweep co-distillation method showed less solvent, simple operation and high recovery rate compared with solvent/solvent extraction method.
박영조,권오관,양정성,이상배 慶南大學校 附設 基礎科學硏究所 1995 硏究論文集 Vol.7 No.-
Chromium(Ⅵ)-heterocyclic complexes, pyrazinium chlorochromate, 4-(dimethylamino) pyridin-ium chlorochromate, 2.2'-bipyridinium chlorochromate, isoquinolinium chlor ochromate, and 2.4'-bipyridinium chlorochromate were synthesized by the react ion of pyrazine, 4-(dimethylamino)pyridine, 2.2'-bipyridine, isoquinoline, 2.4'-bipyridine with chromium trioxide in 6M hydrochloic acid perspectively. Chromium(Ⅵ)-heterocyclic complexes were non-hygroscopic and readily dissolved in water. Their structures were identified with IR spectra and elenental analysis. In case of the process of oxidants for alcohols, the dielectric constants of solvent used influenced on the process of oxidation reaction. DMF was better solvent for the oxidation reaction than DMA, Acetone, CH₂Cl₂.( DMF < DMA < Acetone < CH₂Cl₂)
데페록사민 전처치가 토끼 심근경색 크기의 감소에 미치는 효과
양관모,오동렬,박승현,박규남,이원재,김형국,황두영,최승필,채장성 대한응급의학회 1998 대한응급의학회지 Vol.9 No.4
Background: Reperfusion of ischemic myocardium has been postulated to result in a specific oxygen radical mediated tissue injury. Iron may liberate during ischemia and we hypothesized that administration of the iron chelator, deferoxamine during ischemia would result in improved recovery after postischemic reperfusion. Purpose: To test whether iron-catalyzed processes contribute to myocardial necrosis during ischemia and reperfusion, deferoxamine was administered to block iron catalyzed hydroxyl radical formation in rabbits. Methods: Eleven rabbits were divided into two groups : control group (n=5) and deferoxamine pretreatment group (n=6). The left circumflex coronay artery was ligated for 30 minutes and reperfused for 180 minutes. Area at risk (AR) was measured by non-stained area with methylene blue injection into left atrium after left circumflex coronary artery ligation. Infarct size was measured by weighing after triphenyltetrazolium chloride staining. Heart rate was measured using electrocardiographic recording and systemic blood pressure was monitored by pressure transducer connected to the catheter in the left ventricle. Results: 1. There was no significant difference of heart rate and blood pressure in deferoxamine pretreatment group compared with control group. 2. There was significant decrease of serum iron concentration after continuous infusion of deferoxamine compared with serum iron concentration before ligation of coronary artery(P<0.05). 3. There was no significant difference of area at risk between control and deferoxamine pretreatment group. 4. Area at necrosis to area at risk was significantly reduced in deferoxamine pretreatment group compared with control group(P<0.05). The results suggest that deferoxamine infusion prior to coronary artery occlusion has a significant benefit in reducing infarct size in this model.