• 한국결정성장학회지
• /
• 제23권2호
• /
• pp.101-107
• /
• 2013

재생 세륨 전구체로부터 수산화세륨($Ce(OH)_3$), 염화세륨($CeCl_3{\cdot}nH_2O$), 탄산세륨($Ce_2(CO_3)_3{\cdot}8H_2O$) 및 산화세륨($CeO_2$)을 합성하고 Ultra-sonication을 통해 나노입자의 산화세륨(IV)을 제조하였다. 폐 유리연마재로부터 정제한 약 99 wt% 재생 세륨 분말을 출발물질로 하여 황산침출과 황산나트륨의 첨가조건을 통해서 황산나트륨세륨 화합물($CeNa(SO_4)_2$)을 합성하였다. 또한 황산나트륨세륨 화합물과 수산화나트륨 수용액 첨가량 비의 조건을 달리하여 수산화세륨을 제조하였으며 염산의 첨가량에 따라 염화세륨을 합성하였다. 연속적인 합성공정으로 침상형의 탄산세륨을 합성한 후 하소와 분산을 통해서 평균 30~40 nm의 산화세륨(IV)을 합성하였다.

• Journal of Information Display
• /
• 제7권3호
• /
• pp.13-18
• /
• 2006

Currently, the flexible organic light emitting devices (OLEDs) are investigated. They are very vulnerable to moisture, and thus have been found to show some problems. Thus, an effective barrier layer is needed to protect from moisture in air. We deposited thin films with magnesium oxide (MgO) and silicon oxide $(SiO_{2})$ compounds mixed at various mixture ratios on flexible polyether sulfone (PES) substrates by an electron-beam evaporator to investigate their applizability for transparent barrier applications. In this study, we found that as the MgO fraction increased, thin films comprised of MgO and $(SiO_{2})$ compounds became more amorphous and their surface morphologies become smoother and denser. In addition, zirconium oxide $(ZrO_{2})$ was added to the above-mentioned compound mixtures. $ZrO_{2}$ made thin mixture films more amorphous and made the surface morphology denser and more uniform. The water vapor transmission rates (WVTRs) of the whole films decreased rapidly. The best WVTR was obtained by depositing thin films of Mg-Si-Zr-O compound among the whole thin films. As the thin mixture films became more amorphous, and the surface morphology become denser and more uniform, the WVTRs decreased. Therefore, the thin mixture films became more suitable for flexible OLED applications as transparent passivation layers against moisture in air.

• The Plant Pathology Journal
• /
• 제29권4호
• /
• pp.427-434
• /
• 2013

2R,3R-Butanediol, a volatile compound produced by certain rhizobacteria, is involved in induced drought tolerance in Arabidopsis thaliana through mechanisms involving stomatal closure. In this study, we examined the involvement of nitric oxide and hydrogen peroxide in induced drought tolerance, because these are signaling agents in drought stress responses mediated by abscisic acid (ABA). Fluorescence-based assays showed that systemic nitric oxide and hydrogen peroxide production was induced by 2R,3R-butanediol and correlated with expression of genes encoding nitrate reductase and nitric oxide synthase. Co-treatment of 2R,3R-butanediol with an inhibitor of nitrate reductase or an inhibitor of nitric oxide synthase lowered nitric oxide production and lessened induced drought tolerance. Increases in hydrogen peroxide were negated by co-treatment of 2R,3R-butanediol with inhibitors of NADPH oxidase, or peroxidase. These findings support the volatile 2R,3R-butanediol synthesized by certain rhizobacteria is an active player in induction of drought tolerance through mechanisms involving nitric oxide and hydrogen peroxide production.

• 한국재료학회지
• /
• 제28권9호
• /
• pp.495-498
• /
• 2018

Intermetallic compound matrix composites have been expected to be established as high temperature structural components. $Ni_3Al$ is a representative intermetallic alloy, which has excellent ductility even at room temperature by adding certain alloying elements. $Ni_3Al$ matrix composites with aluminum oxide particles, which are formed by the in-situ reaction between the alloy and aluminum borate whiskers, are fabricated by a powder metallurgical method. The addition of aluminum borate whiskers disperses the synthetic aluminum oxide particles during sintering and dramatically increases the strength of the composite. The uniform dispersion of reaction synthesized aluminum oxide particles and the uniform solution of boron in the matrix seem to play an important role in the improvement in strength. There is a dramatic increase in strength with the addition of the whisker, and the maximum value is obtained at a 10 vol% addition of whisker. The $Ni_3Al$ composite with 10 vol% aluminum oxide particles $0.3{\mu}m$ in size and with 0.1 wt% boron powder fabricated by the conventional powder metallurgical process does not have such high strength because of inhomogeneous distribution of aluminum oxide particles and of boron. The tensile strength of the $Ni_3Al$ with a 10 vol% aluminum borate whisker reaches more than twice the value, 930 MPa, of the parent alloy. No third phase is observed between the aluminum oxide and the matrix.

• 동의생리병리학회지
• /
• 제23권2호
• /
• pp.381-388
• /
• 2009

The present study was conducted to investigate the anti-allergic activity of Galgeunhaegi-Tang(GHT). We investigated the anti-allergic effects of GHT in RBL-2H3 basophilic leukemia cells by compound48/80, a mast cell degranulator and compound 48/80 induced anaphylactic shock in mice. GHT significantly inhibited ${\beta}$-hexosaminidase and histamine release from compound 48/80 stimulated RBL-2H3 cells. In addition, GHT effectively inhibited anaphylactic shock in mice by 40% at a dose 100 mg/mouse versus PBS treated control after the l.p injection(8 mg/kg) of compound 48/80. The in vitro anti-inflammatory activities of GHT in LPS-stimulated RAW 264.7 cells were investigated. GHT inhibited NO production in LPS-stimulated RAW 264.7 cells and effectively dowregulated the expression of iNOS mRNA and iNOS protein expression in LPS-stimulated RAW 264.7 cells. These result provide evidences that GHT may be beneficial in the treatment of allergic inflammtory disease.

• 한국생명과학회:학술대회논문집
• /
• 한국생명과학회 2006년도 제47회 학술심포지움 및 추계국제학술대회
• /
• pp.61.1-61.1
• /
• 2006

• Biomolecules & Therapeutics
• /
• 제4권3호
• /
• pp.275-279
• /
• 1996

We have synthesized the cinnamyl derivative of minoxidil, N-2-cinnamylamino-4-amino-6-piperidinopyrimidine 3-oxide(MINAMYL). Physicochemical properties and structural analysis on this compound were examined. And also, we have screened its antialopecic effect.

• 약학회지
• /
• 제28권1호
• /
• pp.1-10
• /
• 1984

A total synthesis of dehydrojuvabione which has high juvenile hormone activity, is described. The kinetic enloate of mesityl oxide is used as nucleophilic synthon for this synthesis. 1,4-Dioxaspiro [4,5] decan-8-carboxaldehyde was treated with kinetic enolate of mesityl oxide to give 8-(1'-hydroxy-5'-methyl-3'-oxo-4'-hexenyl)-1,4-dioxaspiro [4,5] decane. The latter compound was dehydrated. The resulted dienone was treated with lithium dimethylcuprate. After that, appropriate transformation was performed to give dehydrojuvabione.

• 청정기술
• /
• 제23권4호
• /
• pp.378-387
• /
• 2017

영구적 난연성기를 함유한 에폭시 수지를 얻기 위하여, 본 연구에서는 디하이드록시를 함유한 인 화합물[10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phospha phenanthrene-10-oxide, DOPO-HQ]과 디하이드록시를 함유한 실리콘 화합물(polydimethylsiloxane, hydroxyl terminated, PDMS)를 경화하지 않은 에폭시 프리폴리머(diglycidyl ether of bisphenol A, DGEBA)와 반응시킨 다음, 경화제(4,4-diaminodiphenylmethane, DDM)를 사용하여 경화반응 시킨 에폭시 수지를 제조하였다. 제조된 에폭시 수지의 각종 특성을 적외선 분광분석기(FTIR), 시차주사열량기(DSC), 열중량 분석기(TGA), 한계산소지수(LOI)/수직 연소 시험(UL 94-V test), 인장 및 충격 시험을 이용하여 분석하였다. 그리고 사용한 인 및 실리콘 화합물의 함량이 에폭시 경화물의 열적/기계적 성질 및 난연성에 미치는 영향을 조사하였다. 인 및 실리콘 성분이 함유된 에폭시 수지의 열적 및 기계적 물성이 단순 에폭시 수지의 물성에 비교하여 크게 향상되었다는 것을 알 수 있었다. 그리고 인 및 실리콘을 함유한 모든 에폭시 수지는 29.9 ~ 31.8%의 LOI 및 V-0 수준의 UL 94-V로 난연성 기준(LOI: 30% 이상, UL 94-V: V-0)을 통과한 반면, 단순 에폭시 수지는 LOI: 21.4% 및 UL 94-V: no rating으로 난연성 기준에 크게 못 미치는 것을 알 수 있었다.

• 한국재료학회지
• /
• 제15권10호
• /
• pp.662-666
• /
• 2005

Solid solutions of $(Zr/Ti)O_2$ were prepared in powder form by the coprecipitation technique. After mixing with carbon or exposing to nitrogen gas at elevated temperature, titanium cations selectively diffused out from the oxide compound to form titanium carbide (TiC) or titanium nitride (TiN), respectively. TiN formed strong interfacial contacts between the oxide grains. In contrast, TiC formed as small crystallites on oxide grains but did not bind the matrix grains together. TiN therefore played a role in strengthening the interparticle bonding, but TiC weakened the bonding between grains. Partial diffusion of titanium cations also led to nanolayered structure being formed between the oxide grains, which provided weak interfacial layers that fractured in a step-wise fashion.