• Bulletin of the Korean Chemical Society
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• 제29권7호
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• pp.1369-1373
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• 2008

A stable twist boat conformation of thiane S-oxide 1a in solid state and in solution was unambiguously determined by single crystal X-ray crystallography and solution NMR analyses. On the contrary, the thiane Sdioxide 2 which was obtained from the oxidation of corresponding thiane S-oxide 1a was confirmed to adopt a regular chair conformation.

• 광물과 암석
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• 제36권4호
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• pp.303-312
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• 2023

망가니즈 단괴를 구성하고 있는 금속 원소의 산화상태의 규명은 단괴의 형성기작 및 성인에 대한 이해를 증진시키고 단괴 형성 당시 수계의 산화-환원 전위 등의 고해양 환경에 대한 단서를 제공한다. 본 연구에서는 상용 X선 광전자 분광분석(X-ray photoelectron spectroscopy; XPS)을 활용하여 자연계 망가니즈 단괴를 구성하는 광물의 결합상태와 금속 원소의 산화상태에 대한 정보를 획득하고자 하였다. 이를 위하여 위하여 광물학적 변동의 영향이 효과적으로 기록된 동시베리아해 천해 단괴를 그 연구의 대상으로 삼았다. XPS Mn 2p 스펙트럼 분석 결과, 단괴의 중심부에서 외곽부로 이동함에 따라 망가니즈 산화 상태에 유의미한 변화가 있음을 확인할 수 있었다. 단괴의 중심부는 Mn⁴⁺가 약 67.9%의 비율을 보이는 반면, 단괴의 최외곽부는 환원된 형태의 Mn³⁺+Mn²⁺의 증가로 인해 Mn⁴⁺의 비율이 약 63%로 감소하였다. 이와 같은 단괴 성장에 따른 망가니즈 산화수의 감소는 단괴가 성장함에 따라 토도로카이트에서 버네사이트로 산화망가니즈 광물종이 변화한다는 기존 연구 결과로 설명된다. 또한 O 1s 스펙트럼 분석 결과 단괴 중심부에 비하여 외곽에서 Mn-O-H 결합이 우세하게 나타나는데, 이는 층상형 버네사이트가 우세한 외곽부에서 보다 해수 혹은 공극수로 인한 수화가 효과적으로 일어났음을 시사한다. 본 연구 결과는 망가니즈 단괴의 성장 중 수계의 산화-환원 양상 등 고해양 조건의 변동에 대해 XPS 방법론이 직접적으로 활용될 수 있음을 제시하며, 향후 보다 높은 분해능의 방사광 X선원을 이용한 실험을 통해 보다 세밀한 단위의 망가니즈 산화수 정보의 획득 및 미량 금속원소의 산화 상태 연구가 가능할 것임을 보여준다.

• 전기학회논문지
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• 제61권9호
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• pp.1340-1349
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• 2012

Increasing the oxidation of fat through exercise is the recommendable method for weight control. Preceding researches have proposed increase in the usage of fat during exercise in stabilized state and under maximum exertion through aerobic training. However, such researches require additional equipment for gas analysis in order to measure the caloric value or gas exchange of subjects during exercise. Such equipments become highly restrictive for those exercise and cause substantially higher cost. According to this, we have presented the method of estimating the maximal fat oxidation point through changes in LF & HF which reflects changes in heart rate and the autonomic nervous system in order to induce exercise for a less restrictive and efficient fat oxidation than existing methods. We have conducted exercise stress test on subject with similar exercise abilities, and have detected the changes in heart rate and changes in LF & HF by measuring changes in fat oxidation and measuring ECG signals at the same time through a gas analyzer. Changes in heart rate and HRV of the subjects during exercising was detected through only the electrocardiographic signals from exercising and detected the point of maximum fat oxidation that differs from person to person. The experiment was carried out 16 healthy males, and used Modified Bruce Protocol, which is one of the methods of exercise stress test methods that use treadmill. The fat oxidation amount during exercise of all the subjects showed fat oxidation of more than 4Fkcal/min in the exercise intensity from about 5 minutes to 10 minutes. The correlation between the maximal fat oxidation point obtained through gas analysis and the point when 60% starts to be relevant in the range from -0.01 to 0.01 seconds for values of R-R interval from changes in heart rate had correlation coefficients of 0.855 in Kendall's method and in Spearman's rho, it showed significant results of it being p<0.01 with 0.950, respectively. Furthermore, in the changes in LF & HF, we have determined the point where the normalized area value starts to become the same as the maximal fat oxidation point, and the correlation here showed 0.620 in Kendall and 0.780 in Spearma of which both showed significant results as p<0.01.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.418.2-418.2
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• 2016

$Al_2O_3$ passivation layer has excellent passivation properties at p-type Si surface. This $Al_2O_3$ layer forms thin $SiO_2$ layer at the interface. There were some studies about inserting thermal oxidation process to replace naturally grown oxide during $Al_2O_3$ deposition. They showed improving passivation properties. However, thermal oxidation process has disadvantage of expensive equipment and difficult control of thin layer formation. Wet chemical oxidation has advantages of low cost and easy thin oxide formation. In this study, $Al_2O_3$/$SiO_2/Si(100)$ interface was formed by wet chemical oxidation and PA-ALD process. $SiO_2$ layer at Si wafer was formed by $HCl/H_2O_2$, $H_2SO_4/H_2O_2$ and $HNO_3$, respectively. 20nm $Al_2O_3$ layer on $SiO_2/Si$ was deposited by PA-ALD. This $Al_2O_3/SiO_2/Si(100)$ interface were characterized by capacitance-voltage characteristics and quasi-steady-state photoconductance decay method.

• Nuclear Engineering and Technology
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• 제33권3호
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• pp.307-314
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• 2001

The changes of weight gain, structure, morphology and uranium oxidation states in l0wt% G $d_2$ $O_3$-doped U $O_2$ during the oxidation below 475$^{\circ}C$ and heat treatment at 130$0^{\circ}C$ in air were investigated using TGA, XRD, SEM, EPMA and XPS. The room temperature ( $U_{0.86}$G $d_{0.14}$) $O_2$Cubic Phase Converted to highly distorted ( $U_{0.86}$G $d_{0.14}$)$_3$ $O_{8}$ -type sing1e Phase by oxidation at 475 $^{\circ}C$ in air. This oxidized phase was reduced by annealing at 130$0^{\circ}C$ in air. The room temperature XRD pattern of the 130$0^{\circ}C$ annealed powder revealed that ( $U_{0.86}$G $d_{0.14}$)$_3$ $O_{8}$ -type single phase was separated into Gd-depleted $U_3$ $O_{8}$ and Gd-enriched ( $U_{0.7}$G $d_{0.3}$) $O_2$$_{+x}$ type cubic phase. The reduction and phase separation by the high temperature annealing of kinetically metastable and highly deformed ( $U_{0.86}$G $d_{0.14}$)$_3$ $O_{8}$ -type phase are interpreted in terms of cation size difference between G $d^3$$^{+}$ and U according to the oxidation state of U.U.U.U.U.te of U.U.U.U.U.

• Progress in Superconductivity
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• 제7권1호
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• pp.58-63
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• 2005

We investigated the surface oxidation behavior of cube-textured polycrystalline nickel at various oxidation conditions. Cube-textured NiO film was formed on a cube-textured polycrystalline nickel regardless of oxidation conditions but different growth behavior of NiO crystals was observed depending on the oxidation conditions. The introduction of water vapor into $O_2$ did not affect the texture evolution, but rough and porous microstructure was developed. Microstructure of NiO film tends to be denser as the oxygen partial pressure increases. It is interesting that (111) peak of theta - two theta diffraction pattern started to get stronger in air atmosphere and (111) plane became the major texture in the substrate oxidized in high purity argon gas. Small amount of high index crystallographic plane NiO peak crystal was observed when $N_{2}O$ was used as an oxidant while only (200) plane crystal was formed in dry $O_2$ atmosphere. Flat and smooth surface was changed into rough faceted one when ramping rate to oxidation temperature was faster. The grain size of NiO was decreased when the oxygen partial pressure was low. It was also observed that the modification of nickel surface suppressed the development of (200) texture.

• 대한환경공학회지
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• 제27권5호
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• pp.513-518
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• 2005

망간 산화물 촉매, 망간-세륨 산화물 촉매에서 톨루엔의 촉매 산화에 대하여 조사 하였다. XRD, TGA, 톨루엔-TPR 분석을 통해 촉매의 특성을 조사하였다. 톨루엔 산화반응에 있어서 망간 18.2 wt.% 세륨 10.0 wt.%이 적절한 비율인 것으로 나타났다. 그리고 세리아가 망간 산화물에서의 활성을 증진 시키는 것으로 보여진다. XRD결과 $MnO_2$가 황성 자리인 것으로 추측된다. TGA 톨루엔-TPR결과 세리아가 격자 산소의 이동성, 활성자리의 적절한 상화 상태, 저온에서의 환원능력 및 활성자리의 재산화 능력을 증진시키는 것으로 사료된다.

• Bulletin of the Korean Chemical Society
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• 제25권8호
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• pp.1238-1240
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• 2004

• Bulletin of the Korean Chemical Society
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• 제17권11호
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• pp.1085-1087
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• 1996

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.928-932
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• 2008

A glassy carbon electrode (GCE) modified with poly(p-aminobenzene sulfonic acid) [Poly(p-ABSA)] film is fabricated by voltammetric technique in phosphate buffer solution (pH 8.0) containing $5.0\;{\times}\;10^{-3}\;mol\;L^{-1}$p- ABSA. Electrochemical behaviors of tryptophan at the Poly(p-ABSA) film electrode are investigated with voltammetry. The results indicate that the electrochemical response of tryptophan is improved significantly in the presence of poly(p-ABSA) film. Compared with the bare glassy carbon electrode, the Poly(p-ABSA) film electrode remarkably enhances the irreversible oxidation peak current of tryptophan. Some parameters such as voltammetric sweeping segments for the electrochemical polymerization, pH, accumulation potential and accumulation time are optimized. Under the optimal conditions, the oxidation peak current is proportional to tryptophan concentration in the range of $1.0\;{\times}\;10^{-7}$ to $1.0\;{\times}\;10^{-6}\;mol\;L^{-1}$, and $2.0\;{\times}\;10^{-6}$ to $1.0\;{\times}\;10^{-5}\;mol\;L^{-1}$ with a detection limit of $7.0\;{\times}\;10^{-8}\;mol\;L^{-1}$. The proposed procedure is successfully applied to the determination of tryptophan in a commercial amino acid oral solution.