• 한국결정성장학회지
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• 제31권6호
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• pp.270-275
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• 2021

ZnO는 출발물질인 황산아연과 알칼리 침전제인 NaOH와 Na₂CO₃에 의해 생성된 아연 중간생성물의 변이 거동과 결정화 조건에 따라 제조하였다. ZnO 결정화를 위해 아연 중간생성물인 Zn₄(OH)₆SO₄·H₂O, Zn₅(OH)₆(CO₃)₂·H₂O를 각각 400℃, 800℃에서 1시간 하소하였고, 하소 온도는 열중량 분석을 기반으로 하였다. 아연 중간생성물인 Zn₄(OH)₆SO₄·H₂O은 400℃에서 Zn₄(OH)₆SO₄·H₂O, ZnO 결정상이 혼재됨을 확인하였고, 800℃에서 완전히 열분해되어 순수한 ZnO만 형성되었다. Na₂CO₃와 반응하여 생성된 아연 중간생성물인 Zn₅(OH)₆(CO₃)₂·H₂O는 400℃ 이상에서 완전한 ZnO의 결정상을 확인하였다. Na₂CO₃와 반응을 통해 상대적으로 낮은 하소 온도에서 나노 입자의 ZnO를 합성할 수 있었다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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• pp.129-136
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• 2003

Numerical study with momentum-balanced boundary conditions has been conducted to grasp chemical effects of added $CO_{2}$ and $H_{2}O$ to fuel- and oxidizer-sides on flame structure and NO emission behavior in $CH_{4}$/Air counterflow diffusion flames. The dilution with $H_{2}O$ results in significantly higher flame temperatures and NO emission, but dilution with $CO_{2}$ has much more chemical effects than that with $H_{2}O$. Maximum reaction rate of principal chain branching reaction due to chemical effects decreases with added $CO_{2}$. but increases with added $H_{2}O$. The NO emission behavior is closely related to the production rate of OH, CH and N. The OH radical production rate increases with added $H_{2}O$ but those of CH, N decrease. On the other hand the production rates of OR CH and N decrease with added $CO_{2}$. It is found that NO emission behavior is considerably affected by chemical effects of added $CO_{2}$ and $H_{2}O$.

• 한국결정학회지
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• 제5권2호
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• pp.108-112
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• 1994

C19H20O5, Mr=314.337,삼사정계,PI, a=10.291(2)A, b=11.218(3)A, c=3.059(1)A, α=74.54(2)°,β=1148.84(1)°,r=109.84(2)°,V=883.283(2)A3, λ(Mo Kα)=0.71069A, μ=0.47 mm-1, F(000)=324, 296K, Z=2, Dx=1.18Mgm-3. 1637[F>3σ(F)]개 독립 반사면에 대한 최종 R=0.0580이다. α,β-diphenylsuccinic acid,C16H14O4, 분자들은 O(4)-H˙˙˙O(5)수소결합에 의하여 용체인 acetone과 결합되어 있고 중심대칭관계에 있는 dimer는 분자간의 carboxylic 수소결합 O(1)-H˙˙˙O(2)(-x,-y,-z)에 의하여 결합되어 있다. Dimer간의 가장 가까운 거리 3.288A[O(2)˙˙˙O(2)(-x,-y,-z)]은 분자들의 packing이 van der Waals 력으로 이루어졌음을 보인다.

• 대한화학회지
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• 제24권6호
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• pp.444-451
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• 1980

극성용매에서 전자의 용매화과정을 구체적으로 고찰하여 보기 위하여 테트라히드로퓨란(THF)-물 이성분계의 메디움효과를 측정하였다. 이 메디움효과는 Pt|$H_2Q$, Q, HCI, THF, $H_2O$|KC1 | $Hg_2Cl_2$|Hg(Pt) 셀로 수용액과 다른 용액(TGF-$H_2O$)에서 결정된 $H^+$ 이온에 대한 자유에너지 변화의 차(${\Delta}{\Delta}G_0$)를 이용하여 연구하였다. 여기서 $H_2Q$와 Q는 히드로퀴논과 퀴논을 각각 나타낸다. 자유에너지 변화의 차와 용매화된 전자의 최대흡수 에너지에 대한 용매의 유전상수 영향을 고찰하기 위하여 THF에서 $H_2O$의 회합정도를 관찰하였다. $H_2O$의 회합정도는 $H_2O$의 근적외선 스펙트럼을 이용하여 분석하였다. 이들 실험결과로부터 이성분 혼합용매에서 전자나 다른 이온의 용매화는 용매의 특정성분과 선택적으로 진행된다는 것을 알았다.

• Korean Chemical Engineering Research
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• 제49권5호
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• pp.541-547
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• 2011

$MnSO_45H_2O$와 $(NH_4)S_2O_8$의 수열반응으로 1차원 나노로드들이 침상으로 클러스터화된 구조의 $MnO_2$를 제조하고 그 모폴로지와 결정성을 분석하였다. 수열반응의 조건에 따라 ${\alpha}$-, ${\beta}$-, ${\gamma}-MnO_2$ 등의 전구체가 제조될 수 있는데, 고농도 반응물 및 높은 수열합성 온도($150^{\circ}C$)에서 전기화학적 활성이 우수한 나노로드 클러스터 ${\beta}-MnO_2$의 생성을 확인하였다. 또한 리튬화제 $LiC_3H_3O_2{\cdot}2H_2O$의 농도와 열처리 온도를 변화시키면서 $MnO_2$를 리튬화하여 스피넬계 $LiMn_2O_4$를 제조하고 리튬이온전지 양전극으로서의 특성을 조사하였다. 결과적으로 나노로드 클러스터형 ${\beta}-MnO_2$로부터 고농도 리튬화제와 $800^{\circ}C$ 열처리를 통해 제조한 $LiMn_2O_4$가 정방형 스피넬에 가장 가까운 구조임을 확인하였으며, 120 mAh/g의 우수한 초기 방전용량을 나타내었다.

• 동의생리병리학회지
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• 제19권4호
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• pp.1062-1067
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• 2005

The purpose of this study was to examine the inhibition effect of Zizania latifolia that has been used heart disease, Diabetes Mellitus and Skin disease for a long time on apoptosis induced by $H_2O_2$ in Neuro2A cell. Neuro2A cells were cultivated in RPMI(GibcoBRL) with $5\%$, FBS and treated with $H_2O_2$, and Zizania latifolia. We measured the cell viability and analyzed DNA fragmentation. Activity of PARP, Cytochrome C, caspase-9, caspase-3, p53, p21, Bax and Bcl-2 in the cell was examined by using western blot. The cell viability in Zizania latifolia treatment (60ug/ml<) decreased significantly compared with that of none treatment. (p<0.001) Zizania latifolia increased cell viability about twice as much as that being injury by $H_2O_2$. (Zizania Latifolia 20ug/ml, $H_2O_2$ 200uM, P<0.001) DNA fragmentation developed by $H_2O_2$, but was not developed in Zizania latifolia treatment. PARP, Cytochrome C, caspase-9 and caspase-3 activated all by $H_2O_2$ but were not activated in Zizania latifolia treatment.. P53, P2l and Bu activated by $H_2O_2$, and Bcl-2 got into inactivation. But the opposite results appeared in Zizania latifolia treatment. In conclusion, these results suggest that Zizania latifolia inhibit the development of DNA fragmentation and apoptosis by $H_2O_2$ and the antioxidant action of Zizania latifolia is effective. More researches about effect of Zizania latifolia are considered to need.

• Journal of Periodontal and Implant Science
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• 제38권4호
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• pp.645-656
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• 2008

Purpose: To evaulate the effects of chlorhexidine and $H_2O_2$ on matrix metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinase(TIMP-1, TIMP-2), Type 1 collagen, fibronectin and UNCL expressions in human periodontal ligament fibroblasts (hPDLF). Materials and Methods: $1.2{\times}10^{-1}%$, $1.2{\times}10^{-2}%$ and $1.2{\times}10^{-3}%$ CHX and $3{\times}10^{-3}%$, $3{\times}10^{-4}%$ and $3{\times}10^{-5}%$ $H_2O_2$ and mixture of CHX and $H_2O_2$ were applied to hPDLF for 1 min and 30 min. The mRNA expressions of MMP-1, TIMP-1 and 2, Type 1 collagen, fibronectin and UNCL in hPDLF were analysed by RT-PCR. Results: The result were as follows: 1. The expression of UNCL mRNA was higher than that of other mRNAs. 2. $1.2{\times}10^{-3}%$ CHX increased mRNA expressions of hPDLF as application time increased. 3. $H_2O_2$ lower than $3{\times}10^{-3}%$ increased expression of UNCL mRNA, and did not decrease mRNA expression of hPDLF. 4. hPDLF treatment with $1.2{\times}10^{-1}%$ CHX (with or without $H_2O_2$) resulted in no gene expression. 5. hPDLF treatment with $1.2{\times}10^{-2}%$ CHX (with or without $H_2O_2$) for 30 minutes resulted in no gene expression. Conclusion: Because low concentration of CHX and $H_2O_2$ increased UNCL mRNA expression of hPDLF, low concentraction of CHX and $H_2O_2$ may have an antioxidative effect.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.871-872
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• 2009

본 연구에서는 석탄가스에 함유된 $H_2O/H_2S$ 농도변화에 따른 세가지 종류의 아연계 탈황제의 반응성능을 회분식 유동층반응기에서 분석하였다. 가스화에서 생성되는 가스의 조성은 모사가스를 이용하여 입구의 $H_2O$와 $H_2S$ 농도를 변화시켜 실험을 수행하였다. $H_2O$의 농도는 5%부터 30%까지 $H_2S$의 농도는 0.5%에서 2%로 변화시켜 탈황성능을 분석하였다. 실험 결과 $H_2O$의 농도가 증가할수록 탈황성능이 감소하였다. 입구의 $H_2S$ 농도가 증가할수록 탈황반응기 후단의 $H_2S$ 농도 역시 증가하였으나, 탈황성능은 최저 99.5%로 건식탈황제를 이용하여 99% 이상의 $H_2S$ 제거 성능을 보이는 것을 확인하였다.

• 한국수소및신에너지학회논문집
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• 제16권1호
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• pp.9-16
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• 2005

We studied the electrochromic properties of hydrated amorphous ruthenium oxide ($RuO_2{\cdot}xH_2O$) thin films using in-situ Raman spectroscopy during electrochemical charging/discharging cycles. We have found that the principal effect of hydrogen insertion into $RuO_2{\cdot}xH_2O$ is reduction of $Ru^{4+}\;to\;Ru^{3+}$, and not formation of new bonds involving hydrogen. We compared the changes in the Raman spectrum of a gasochromic $Pd/RuO_2{\cdot}xH_2O$ film as it is exposed to hydrogen gas with that of electrochemical hydrogen insertion. We tested the changes in the optical transmission of the $Pd/RuO_2{\cdot}xH_2O$ film when exposed to hydrogen gas.

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.964-972
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• 2011

This work investigated the difference between $Fe^{2+}$ autoxidation-induced and Fenton-type cleavage of pBR322 plasmid DNA. $^{\cdot}OH$ generation reactions in the absence and presence of $H_2O_2$ under various conditions were also investigated. Although both the $Fe^{2+}$ autoxidation and Fenton-type reactions showed DNA cleavage and $^{\cdot}OH$ generation, there were significant differences in their efficiencies and reaction rates. The rate and efficiency of the cleavage reaction were higher in the absence of 1.0 mM of $H_2O_2$ than in its presence in 20 mM phosphate buffer. In contrast, the $^{\cdot}OH$ generation reaction was more prominent in the presence of $H_2O_2$ and showed a pH-independent, fast initial reaction rate, but the rate was decreased in the absence of $H_2O_2$ at across the entire tested pH range. Studies using radical scavengers on DNA cleavage and $^{\cdot}OH$ generation reactions in both the absence and presence of $H_2O_2$ confirmed that both reactions spontaneously involved the active oxygen species $^{\cdot}OH$, ${O_2}^{\cdot-}$, $^1O_2$ and $H_2O_2$, indicating that a similar process may participate in both reactions. Based on the above observations, a new mechanism for the $Fe^{2+}$ autoxidation-induced DNA cleavage reaction is proposed.