• 대한화학회지
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• 제33권3호
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• pp.281-286
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• 1989

벤조히드로옥사믹산(Hben)과 이의 옥소바나듐(IV) 착화합물, $VO(Ben)_2$의 전기화학적 거동을 폴라로그래피와 순환 전압 전류법을 이용하여 조사하였다. Hben의 경우, 아세톤 용매중에서 얻은 폴라로그램은 Ag/AgCl 전극에 대해 -0.05V와 -1.78V에서 두개의 환원파를 나타내었다. 첫번째 환원파는 단일 라디칼 음이온의 생성에, 그리고 두번째 환원파는 이중 라디칼 음이온의 생성에 기인하는 것으로 해석되었다. $VO(Ben)_2$ 착물의 폴라로그램은 +0.55V에서 한개의 산화파를, 그리고 -0.15V와 -1.30V에서 각각 한개씩의 환원파를 나타내었다. +0.55V의 전극반응은 1전자 산화과정이었다$(VO(ben)_2 {\rightleftharpoons} VO(ben)^+ + e)$. -0.15V에 나타난 환원파는 준가역적인 역시 1전자 과정이었으며 $VO(Ben)_2^-$라디칼 형성에 의한 것으로 해석되었다. -1.30V에서 나타난 환원파는 비가역적이며 이 과정에서는 바나디움(III)이온을 생성하는 것으로 믿어진다. 산소 주게 원자를 갖는 Hben 리간드는 황이나 질소를 포함하는 다른 리간드들과 비교해 볼 때 중심금속인 바나듐의 +4가 산화상태의 안정성을 감소시키는 것으로 믿어진다.

• Journal of Korean Neurosurgical Society
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• 제39권2호
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• pp.120-124
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• 2006

Objective : This study is aimed to assess the clinical outcome in early and minimally invasive surgery using incision for the patients with poor grade aneurysm. Methods : The authors retrospectively reviewed all 46 poor grade patients of Hunt and Hess[H-H] grade IV and V who suffered aneurysmal subarachnoid hemorrhage[SAH] between 1999 and 2004. All 35 patients harboring 43 aneurysms who underwent early surgery within 72 hours were included in this study. Clinical outcome was assessed by Glasgow outcome scale[GOS] and compared with that of conventional pterional approach. Results : Twenty four patients were operated with conventional pterional approach and 11 with eyebrow approach within 72 hours after SAH. Seven multiple aneurysm patients harbor 15 aneurysms, Forty one aneurysms were treated with clippings. All 11 patients of eyebrow surgery group[ESG] were in H-H grade IV, 3 in Fisher grade III and 8 in Fisher grade IV. Among 24 patients of pterional approach group[PAG]. 20 were in H-H grade IV and 4 in H-H grade V, 3 were in Fisher grade III and 21 in Fisher grade IV. Overall favorable outcome was achieved in 41.7% and 54.5% in PAG and ESG, respectively. Favorable outcome of H-H grade IV in PAG showed 45.0%. Overall mortality rate was 14.3%. Conclusion : It is concluded that the clinical outcome of early and minimally invasive aneurysmal surgery using eyebrow incision in the selected poor grade aneurysm patients can be compatible with that of conventional pterional surgery.

• 전기화학회지
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• 제9권2호
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• pp.59-63
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• 2006

전해코팅 법과 dip-coating 법을 이용해 산화주석(IV)을 티타늄 지지체에 코팅하여, 코팅 방법에 따른 코팅 전극의 물성과 전기화학적 특성에 대해여 연구하였다. HCl 로 전극 에칭 후, nitrate 용액에 $SnCl_2{\cdot}2H_2O$을 용해시켜 pulse technique를 이용하여 전해코팅 하였으며, dip-coating 법 또한 $SnCl_2{\cdot}2H_2O$를 사용하여 1:1V% HCl 용액에 용해시켜 코팅 소결 후 산화주석(IV)코팅 전극을 제작하였다. 두 가지 코팅 방법을 통해 제작된 산화주석(IV)코팅 전극은 전극의 물성을 비교하기 위해 x-ray diffraction (XRD), scanning election microscopy (SEM)를 관찰해보았고, 전기화학적 특성을 평가하기 위해 cyclic voltammetry (CV)를 측정하여 전위창을 비교해 보았다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.19-19
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• 2003

The injection of spins into nonmagnetic semiconductors has recently attracted great interest due to the potential to create new classes of spin-dependent electronic devices. A recent strategy to achieve control over the spin degree of freedom is based on dilute ferromagnetic semiconductors. Ferromagnetism has been reported in various semiconductor groups including II-Ⅵ, III-V, IV and II-IV,-V$_2$, which will be reviewed. On the other hand, to date the low solubility of magnetic ions in non-magnetic semiconductor hosts and/or low Curie temperature have limited the opportunities. Therefore the search for other promising ferromagnetic semiconducting materials, with high magnetic moments and high Curie temperatures (Tc), is of the utmost importance. In this talk, we also introduce new pure ferromagnetic semiconductors, MnGeP$_2$ and MnGeAs$_2$, exhibiting ferromagnetism and a magnetic moment per Mn at 5K larger than 2.40 ${\mu}$B. The calculated electronic structures using the FLAPW method show an indirect energy gap of 0.24 and 0.06 eV, respectively. We have observed spin injection in MnGeP$_2$ and MnGeAs$_2$ magnetic tunnel junctions through semiconducting barriers.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 추계 총회 및 학술발표회
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• pp.199-203
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• 2004

Fibrous arsenic (As) adsorbent was synthesized by loading zirconium (Zr) on fibrous phosphoric adsorbent that was directly synthesized by radiation-induced graft polymerization of 2-hydroxyethyl methacrylate phosphoric acid on polyethylene-coated polypropylene nonwoven fabric. Zirconium reacted with phosphoric acid grafted in the polyethylene layer. Zirconium density of the resulting adsorbent was 4.1 mmol/g. The breakthrough curve of As(V) adsorption was independent of the flow rate up to $1300\;h^{-1}$ in space velocity. The total capacity of As(V) was 2.0 mmol/g-adsorbent at pH of 2. The adsorbed Zr(IV) could be evaluated by 0.4 M sodium hydroxide solution because negligible Zr(IV) could be found in the eluted solution.

• 한국식품위생안전성학회지
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• 제11권2호
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• pp.123-127
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• 1996

The isolation and chemical characterization of yellow food pigments from Monascus purpureus were studied according to the compositions of media. Monacus yellow pigments were isolated and purified by solvent fractionation, silicagel column chromatography, TLC and HPLC. The retention time of Monascus yellow pigments isolated by HPLC was respectively 5 min(I) and 9 min(II) as the yeast malt extract agar(YMA) media and was respectively 4.6 min(III), 5 min(I) 5.7 min(IV), 8.3 min(V), 9 min(II) and 10.7 min(Ⅵ) at the malt extract agar(MEA) media. The structure of monascin(I), ankaflavin(II), 6,11-dihydrorubropunctatin(III), 6,11-dihydromonascorubrin(V) and unknown compounds(IV,Ⅵ) was elucidated by EI-Mass, H and C NMR, UV-visible spectrometer. Therefore, it was suggested that 6,11-dihydrorubropunctatin(III) and 6,11-dihydromonascorubrin(V) are new intermediates of Monascus yellow pigments.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.201-204
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• 2001

In this paper, for modeling of electrical characteristics in Poly Silicon Thin Film Transistors with process parameters set up optimum values, So, the I-V characteristics of poly silicon TFT parameters are examined and simulated in terms of the variations in process parameter. And these results compared and analyzed simulation values with examination value. The simulation program for characteristic analysis used SUPREM IV for processing, Matlab for modeling by mathematics, and SPICE for electric characteristic of devices. Input parameter for simulation characteristics is like condition of device process sequence, these electric characteristic of $I_D-V_D$ $I_D-V_G$, variations of grain size. The Gate oxide thickness of poly silicon are showed similar results between real device characteristics and simulation characteristics.

• Archives of Pharmacal Research
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• 제24권4호
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• pp.312-315
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• 2001

Repeated column chromatographic separation of the $CH_{2}Cl_{2}$ extract of Artemisia stolonofera (Asteraceae) led to the isolation of a triterpene (I), a sesquiterpene (II), two aromatic compounds (III and IV) and a benzoquinone (V). Their structures were determined by spectroscopic means to be simiarenol (I), (1S,7S)-1 $\beta$-hydroxygermacra-4(15),5, 10(14)-triene (II), 3'-methoxy-4'-hydroxy-trans-cinnamaldehyde (III), vanillin(IV) and 2,6-dimethoxy-1,4-benzoquinone (V), respectively. Among these products, compound V showed significant cytotoxicity against five human tumor cell lines in vitro, A549 (non small cell lung adenocarcinoma), SK-OV-3 (ovarian), SK-MEL-2 (skin melanoma), XF498 (CNS) and HCT15 (colon) with ED_{50}$ values ranging from 1.33~4.22${\mu}g/ml$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.201-204
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• 2001

In this paper, for modeling of electrical characteristics in Poly Silicon Thin Film Transistors with process parameters set up optimum values. So, the I-V characteristics of poly silicon TFT parameters are examined and simulated in terms of the variations in process parameter. And these results compared and analyzed simulation values with examination value. The simulation program for characteristic analysis used SUPREM IV for processing, Matlab for modeling by mathematics, and SPICE for electric characteristic of devices. Input parameter for simulation characteristics is like condition of device process sequence, these electric characteristic of I$_{D}$-V$_{D}$, I$_{D}$-V$_{G}$, variations of grain size. The Gate oxide thickness of poly silicon are showed similar results between real device characteristics and simulation characteristics.ristics.

• Bulletin of the Korean Chemical Society
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• 제13권1호
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• pp.32-36
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• 1992

The gas-phase pyrolysis reactions of 2-alkoxypyrimidines(II), 2-alkoxypyrazines(III), 4-ethoxypyrimidine(IV) and 3-ethoxypyridazine(V) are investigated theoretically using the AM1 MO method. These compounds pyrolyze in a concerted retro-ene process with a six-membered cyclic transition state (TS). The relative order of reactivity if (IV)>(II)>(III)>(V), which can be rationalized by the two effects arising from electron-withdrawing power of the aza-substituent: (ⅰ) Electron withdrawal from the C-O bond accelerates the rate and (ⅱ) electron withdrawal from the $N^1$-atom, that is participating in the six-membered TS, deactivates the reaction. We are unable to explain the experimental result of the greatest reactivity for pyridazine, (V), with our AM1 results. The reactivity increase accompanied by successive methylation of the ethoxy group, ethoxytert-butoxy, is due to a release of steric crowding in the activation process.