• 한국세라믹학회지
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• 제28권7호
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• pp.517-524
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• 1991

The CVD process of BPSG (BoroPhosphoSilicate Glass) and its thin film properties were studied. B2H6, PH3, SiH4 and O2 gases were reacted in a AP (Atmospheric Pressure) CVD system in the temperature range of 300℃ and 460℃. The interaction of B2H6 and PH3 was studied from the deposition rate and dopant incorporation change point of view. The dependency of BPSG step coverage on the temperature was changed with different O2/(B2H6+PH3+SiH4) ratio. Finally, the boundary which distinguishes the stable BPSG's from the ones that react with Di (Deionized) water or cleaning chemicals such as H2SO4, HCl, H2O2, NH4OH etc could be defined.

• Bulletin of the Korean Chemical Society
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• 제2권2호
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• pp.37-41
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• 1981

The elution behaviors of molybdate and tungstate through anion exchange column have been investigated in the various concentration of hydrochloric and perchloric acid. A discussion is made to evaluate the existing these equilibrium and constant according to acidity. In both acids of 0.01-2.0 M concentration range, the existing equilibrium for molybdate and its constant calculated at $20^{\circ}C$ is $10^{18.9}$ for $Mo_8O_2^{4-} + 20H^+ {\rightleftharpoons} 8MoO_2^{2+} + 10H_2O$. In the 3-3.5 M hydrochloric acid it is 0.16 for $MoO_2Cl_2 + Cl^- {\rightleftharpoons} MoO_2Cl^{3-}$ and for the case of tungstate, in the both acids of 0.01-1.0 M concentration range $10^{6.6}$ for $W_{12}O_{39}^{6-} + 6H^+ {\rightleftharpoons} 12WO_3{\cdot}3H_2O$. In higher concentration than 1.0 M both acids the following equilibrium seems to be existed. $12WO_3{\cdot}3H_2O {\rightleftharpoons} 12WO_3 + 3H_2O$

• The Korean Journal of Ceramics
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• 제6권1호
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• pp.43-46
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• 2000

$H_4Nb_6/O_{17}$/CdS nanocomposites which intercalated CdS particles, less than 0.8nm thickness, in the interlayer of $H_4Nb_6/O_{17}$ were prepared by the successive ion exchange reactions of $H_4Nb_6/O_{17}$ with $Cd^{2+}$ and $C_3H_7NH_3_+$, followed by the reaction with $H_2S$ gas. $H_4Nb_6/O_{17}$/CdS photocatalytically reduced $NO_3$￣ to $NO_2$￣ and $NH_3$in the presence of sacrificial hole acceptor such as methanol under visible light irradiation (wavelength>400nm), although unsupported CdS showed no noticeable photocatalytic activity for $NO_3$￣ reduction. The catalytic activity of $H_4Nb_6/O_{17}$/CdS greatly enhanced with co-doping of Pt particles in the interlayer.

• Bulletin of the Korean Chemical Society
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• 제21권6호
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• pp.638-640
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• 2000

• 대한화학회지
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• 제45권6호
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• pp.520-523
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• 2001

산성조건에서 $H_2O_2$가 HCr$O^-_4$ 이온과 반응하여 진한 청색의 $CrO(O_2)_2$를 형성하는 반응에 흐름 주입 분석을 도입하여 수용액시료 중 $H_2O_2$의 양을 정량할 수 있는 흡수분광분석법을 개발하였다. 이 분석법에 의한 $H_2O_2$의 정량범의는 2.00${\times}10^{-6}$M∼0.020M이며, 측정한계는 약 1.5${\times}10^{-6}$M이다. 또한, 이 분석법은 실제 강우와 강설 중에 존재하는 과산화수소의 농도결정에도 사용할 수 있음이 밝혀졌다.

• 한국진공학회지
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• 제13권4호
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• pp.139-144
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• 2004

최근에는 진공공정에서 용기내의 청정도와 잔류기체의 부분압에 대한 관심이 높아지고 있다. 본 연구에서는 청정진공 발생에 많이 사용되고 있는 크라이오 펌프의 냉각판 온도에 따른 $H_2$, He, C, N, $O_2$, $H_2O$, Ar/2, $N_2$(CO), Ar, $CO_2$의 부분압을 잔류기체분석기로 측정하여 비교하였다. 크라이오 펌프를 켜고 약 72분이 지났을 때 펌프의 냉각판 온도가 12K에 도달하였으며, 25시간이 경과하여 온도가 충분하게 낮아졌을 때 부분압은 $H_2$, He, C, N, $O_2$, $H_2O$, Ar/2, $N_2$, Ar, $CO_2$순으로 24.9%, 6.6%, 5.5%, 2.2%, 3.8%, 30.7%, 6.5%, 6.1%, 5.5 %, 8.2%로 $H_2$와 $H_2O $압력이 상대적으로 높은 것을 알 수 있었다.

• 한국대기환경학회지
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• 제13권5호
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• pp.397-410
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• 1997

An annular denuder filter pack sampling system (ADS) was used to collect acidic air pollutants in Pusan. During the study period (from June 1995 to November 1995), forty eight samples were collected every 12 hours starting from 6:00 in the morning. These samples were devided into two sets of data for day (6:00 a.m.-6:00 p.m.) and night (6:00 p.m.-6:00 a.m.). The chemical species were analyzed for HN $O_3$, HN $O_2$, S $O_2$ and N $H_3$ in the gas Phase, and N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$ and N $H_4$$^{+}$ in the particulate phase. The mean concentrations measured from this study were 0.24, 1.91, 30.07 and 4.24 $\mu\textrm{g}$/㎥ for HN $O_3$, HN $O_2$, S $O_2$ and N $H_3$, respectively. The mean concentrations of N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$ and N $H_4$$^+{\ulcorner}$ were 1.95, 7.36 and 3.48 $\mu\textrm{g}$/㎥, respectively. The mean concentrations of gaseous species except for HN $O_2$ were higher in daytime than in nighttime, but the reverse was true in the particulates except for N $H_4$$^{+}$. +/..

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1786-1795
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• 2015

It is common practice to identify the insulation faults of GIS through monitor the contents of SF₆ decomposed components. Partial discharges (PD) could lead to the decomposition of SF₆ dielectric, so new reactions usually occur in the mixture of the newly decomposed components including traces of H₂O and O₂. The new reactions also cause the decomposed components to differ due to the different amounts of H₂O and O₂ even under the same strength of PD. Thus, the accuracy of assessing the insulation faults is definitely influenced when using the concentration and corresponding change of decomposed components. In the present research, a needle-plate electrode was employed to simulate the PD event of a metal protrusion insulation fault for two main characteristic components SO₂F₂ and SOF₂, and to carry out influence analysis of trace H₂O and O₂ on the characteristic components. The research shows that trace H₂O has the capability of catching an F atom, which inhibits low-sulfide SF_x from recombining into high-sulfide SF₆. Thus, the amount of SOF₂ strongly correlates to the amount of trace H₂O, whereas the amount of SO₂F₂ is weakly related to trace H₂O. Furthermore, the dilution effect of trace O₂ on SOF₂ obviously exceeds that of SO₂F₂.

• 대한화장품학회지
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• 제34권3호
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• pp.157-165
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• 2008

이전 연구에서 저자들은 나문재 추출물의 항산화 작용과 추출물 함유 크림의 유화 안정성에 대한 결과를 보고한 바 있다[1,2]. 본 연구에서는 thin layer chromatography(TLC), high performance liquid chromatography (HPLC)와 liquid chromatography/Electrospray Tandem mass spectrometry (LC/ESI/MS/MS), $^1H$-NMR을 이용하여 나문재 추출물에 대한 성분 분석을 수행하였다. 나문재 추출물 중 ethyl acetate분획의 TLC는 5개의 띠($SA1{\sim}SA5$)로 분리되었다. Ethyl acetate 분획의 당 제거반응 후 얻어진 aglycone 분획에 대한 HPLC 크로마토그램은 2개의 피이크(SAA 2 및 SAA 1)를 나타냈고, 각각 그 용리 순서는 quercetin, kaempferol이었으며 조성비는 quercetin 16.88%, kaempferol 83.12%로 kaempferol의 함량이 큰 것으로 나타났다. 또한 LC/ESI-MS/MS를 통해서 SA 2는 kaempferol-3-O-gluco-side로 SA 3는 quercetin-e-O-glucoside, SA 4는 kaempferol-3-O-rutinoside, SA 5는 quercetin-3-O-rutinoside로 확인되었다. LC/ESI-MS/MS의 스펙트럼에서 SAA 1은 탈양성자화된 aglycone 분획에 상용하는 분자이온 $[M-H]^$-(m/z285) 피이크를 나타냈으며, $^1$v 분석을 실시한 결과 [${\delta}$ 6.19 (1H, d, J=1.8Hz, H-6), ${\delta}$ 6.44 (1H, d, J=1.8Hz, H-8), ${\delta}$ 6.92 (2H, d, J=9.0Hz, H-3',5'), ${\delta}$ 8.04 (2H, d, J=9.0Hz, H-2',6')]에서 피이크들이 나타났다. 따라서 SAA 1은 kaempferol임이 확인되었다. SAA 2는 aglycone 분획에 상응하는 분자이온 $[M-H]^-$ (m/z 301)을 생성하였고, $^1H$-NMR 스펙트럼은 [${\delta}$ 6.20 (1H, d, J=2.0Hz, H-6), ${\delta}$ 6.42 (1H, d, J=2.0Hz, H-8), ${\delta}$ 6.90 (1H, d, J=8.6Hz, H-5'), ${\delta}$ 7.55 (1H, dd, J=8.6, 2.2Hz, H-6'), ${\delta}$ 7.69 (1H, d, J=2.2Hz, H-2')]에서 피이크들을 나타냈고, 따라서 SAA 2는 quercetin으로 확인되었다. 결론적으로, 이미 보고된 나문재 추출물의 항산화 작용 그리고 안정성 실험과 더불어 나문재 추출물의 성분분석은 새로운 기능성 화장품원료로서 응용이 가능함을 시사한다.

• 한국세라믹학회지
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• 제27권7호
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• pp.899-906
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• 1990

The cordierite powders were prepared from Mg(NO3)2.6H2O, Al(NO3)3.9H2O and colloidal silica by the coprecippitation method, and the sintering behavior of the powders were investigated. Two different methods were applied for producing the precursor powders. The one was to added the aqueous solution of Mg(NO3)2.6H2O and Al(NO3)3.9H2O to NH4OH to adjust pH at 10 where the colloidal silica of pH 10 was added. The other wa to add the aqueous solution of Mg(NO3)2.6H2O and Al(NO3)3.9H2O to the colloidal silica with NH4OH to control the final mixture to be at pH 10. It was confirmed that more homogeneous powders were obtained from the latter method. The firing linear shrinkage of the powder compacts fabricated from the calcined powder between 90$0^{\circ}C$ and 110$0^{\circ}C$ was found to be larger as the calcination temperature was low. But all of them stopped shrinking around 120$0^{\circ}C$. The powder compacts, fabricated using the calcined powders at 90$0^{\circ}C$ and 95$0^{\circ}C$ for 2hours and sintered at 142$0^{\circ}C$ for 2hours, showed relative density of 93-96%, 3-point bending strength of 81-83MPa, KIC of 1.9-2.4 MPam1/2 and thermal expansion coefficient of 0.213-0.732$\times$10-6$^{\circ}C$.