• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.237-238
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• 2006

The electrical properties such as dielectric constants and dielectric losses in the spinel samples of $LiGaTiO_4$, Li(Ga,Eu)$TiO_4$, $Li(Ga.Yb)TiO_4$ have been characterized by varying measuring temperature and frequency. The long range order structures are analyzed by rietveld refinement method. and local atomic disorder structures are analyzed by MEM (maximum entropy method). The relation between the crystal structure and dielectric properties are discussed. $LiGaTiO_4$ spinel has the IMMA with lattice constant, a = 5.86333, b=17.5872. c = 8.28375 ${\AA}$, Li-sites are partially substituted by Ga or Ti. Two crystallographic oxygen sites are partially occupied(40~50%). The dielectric constants of $LiGaTiO_4$, $LiYbTiO_4$, and $LiGa_{2/6}Eu_{1/6}Ti_{1.5}O_4$ ceramics were 127, 75 and 272, respectively at 100 kHz. The dielectric relaxation were observed in the $LiGaTiO_3$ ceramics and the temperature where dielectric loss shows maximum was $390^{\circ}C$ at 1 kHz and increased with increasing the measuring frequency.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 춘계학술대회
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• pp.696-698
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• 2011

박막 벌크 음향 공진 소자 (Film Bulk Acoustic Resonator, FBAR) 기술은 현 실리콘 공정 기술과 호환되며 차세대 초소형 RF소자 구현을 가능하게 하는 기술로 각광받아 오고 있다. FBAR 소자 제작 시 박막 증착에 RF 스퍼터링 (sputtering) 방식을 이용하는 경우 산소 ($O_2$) 및 아르곤 (Ar)의 혼합가스 분위기에서 증착하는 것이 통상적이다. 본 논문에서는 아산화질소 ($N_2O$) 및 아르곤 (Ar)의 혼합가스 분위기에서 RF 스퍼터링 방식으로 증착된 고품위의 산화아연 (Zinc Oxide, ZnO) 압전(piezoelectric) 박막을 적용하여 FBAR 소자를 제작하는 새로운 방법을 제시한다. 이때 소자 제작과정에 다양한 조건에서의 열처리 과정 (thermal annealing treatments)이 수반되었으며, 이러한 공정조건이 제작된 FBAR 소자의 공진특성 (resonance characteristics)에 미치는 영향을 반사손실 (return loss)의 측면에서 조사하였다. 결과적으로, 공정 조건을 최적화함으로써 ~2.9 MHz 에서 매우 우수한 공진특성을 가지는 FBAR 소자를 제작할 수 있었다.

• 한국수소및신에너지학회논문집
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• 제14권1호
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• pp.24-34
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• 2003

For gaseous fuel combustion with inherent $CO_2$ capture and low NOx emission, chemical-looping combustion may yield great advantages for the savings of energy to $CO_2$ separation and suppressing the effect on environment, In chemical-looping combustor, fuel is oxidized by metal oxide medium in a reduction reactor. Reduced particles are transported to oxidation reactor and oxidized by air and recycled to reduction reactor. The fuel and the air are never mixed, and the gases from reduction reactor, $CO_2$ and $H_2O$, leave the system as separate stream. The $H_2O$ can be easily separated by condensation and pure $CO_2$ is obtained without any loss of energy for separation. In this study, five oxygen carrier particles such as NiO/bentonite, NiO/YSZ, $(NiO+Fe_2O_3)VYSZ$, $NiO/NiAl_2O_4$, and $Co_{\chi}O_y/CoAl_2O_4$ were examined &om the viewpoints of reaction kinetics, oxygen transfer capacity, and carbon deposition characteristics. Among five oxygen particles, NiO/YSZ particle is superior in reaction rate, oxygen carrier capacity, and carbon deposition to other particles. However, at high temperature ($>900^{\circ}C$), NiO/bentonite particle also shows enough reactivity and oxygen carrier capacity to be applied in a practical system.

• 한국전기전자재료학회논문지
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• 제25권7호
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• pp.506-510
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• 2012

In this study, lead-free $(Na_{0.465}K_{0.465}Bi_{0.07})(Nb_{0.93}Ti_{0.07})O_3-0.08MnO_2$ ceramics were fabricated by conventional mixed oxide method. Structural and electrical properties of lead-free $(Na_{0.465}K_{0.465}Bi_{0.07})(Nb_{0.93}Ti_{0.07})O_3-0.08MnO_2$ ceramics with the variation of sintering temperature were investigated. As results of x-ray diffraction analysis, all specimens showed a typical polycrystalline perovskite structure without presence of the second phase. Sintered density increased with an increases of sintering temperature and the specimen sintered at $1,020^{\circ}C$ showed the maximum value of 4.5 $g/cm^3$. The average grain size of the $(Na_{0.465}K_{0.465}Bi_{0.07})(Nb_{0.93}Ti_{0.07})O_3-0.08MnO_2$ specimen sintered at $1,020^{\circ}C$ is about 0.83 ${\mu}m$. Electromechanical coupling factor, relative dielectric constant and dielectric loss of $(Na_{0.465}K_{0.465}Bi_{0.07})(Nb_{0.93}Ti_{0.07})O_3-0.08MnO_2$ specimens sintered at $1,020^{\circ}C$ were 0.252, 741 and 0.043% respectively.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.83-83
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• 2003

In our previous study, glucose deprivation was reported to induce the potentiated death and ATP loss in immunostimulated astroglia. And this vulnerability to glucose deprivation was due to overproduction of nitric oxide (NO) and hydrogen peroxide (H$_2$O$_2$). In the present study, the role of extracellular signal-regulated kinase 1/2 (ERK1/2) in the glucose deprivation-induced death of immunostimulated astroglia was examined. We showed that immunostimulation with LPS+IFN-ν activated the ERKl/2 signal pathway and produced a large amount of NO and H$_2$O$_2$. Generation of NO and H$_2$O$_2$ in immunostimulated astroglia was mediated via ERK1/2 signal pathways, since addition of the ERK kinase (MEKl) inhibitor PD98059 reduced NO and H$_2$O$_2$production. ERK1/2 activation-mediated NO and H$_2$O$_2$ production is due to an activation of iNOS and NADPH oxidase, respectively. Finally, we found that glucose deprivation caused ATP depletion and the augmented death in immunostimulated astroglia, which was also prevented by PD98059 treatment. These results demonstrate that the ERK1/2 signal pathways play an important role in glucose deprivation induced the death in immunostimulated astroglia by regulating the generation of NO and H$_2$O$_2$.

• 한국전기전자재료학회논문지
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• 제11권2호
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• pp.111-120
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• 1998

In this paper, the $(SrPb)(CaMg)TiO_3$ ceramics with paraelectric properties were fabricated by the mixed oxide method. It was investigated that which the variation of contents of $Bi_2O_3{\cdot}3TiO_2$ effects on structural, dielectrical and electrical properties of specimens. As a result, the grain size were grown with increasing the contents of $Bi_2O_3{\cdot}3TiO_2$. The relative dielectric constants were increased up to 4[mol%] of $Bi_2O_3{\cdot}3TiO_2$, and decreased more or less at a low temperature in the specimens which had more than. But the temperature coefficient. of capacitance were showed ${\pm}25$[%]. The dielectric loss were less than 0.05 in all specimens which had more than 4[mol%] of $Bi_2O_3{\cdot}3TiO_2$. In order to investigate the behavior of charged particles, the characteristics of electrical conduction were measured. As a result, the conduction current was divided into the three steps as a function of DC electric field. The first step was Ohmic region due to ionic conduction, below 15[kV/cm]. The second step was showed a saturation which seems to be related to a depolarizing field occuring in field-enforced ferroelectric phase, between 15[kV/cm] and 40[kV/cm]. The third step was attributed to Child's law related to space charge which injected from electrode, above 40[kV/cm].

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.193.1-193.1
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• 2014

This study was to investigate the electronic structure and optical properties of Na doped into NiO thin film using XPS and REELS. The films were grown by electron beam evaporation with varying the annealing temperature. The relationship between the electrical characteristics with the local structure of NiO thin films was also discussed. The x-ray photoelectron results showed that the Ni 2p spectra for all films consist of Ni 2p3/2 which indicate the presence of Ni-O bond from NiO phase and for the annealed film at temperature above $200^{\circ}C$ shows the coexist Ni oxide and Ni metal phase. The reflection electron energy loss spectroscopy spectra showed that the band gaps of the NiO thin films were slightly decreased with Na-doped into films. The Na-doped NiO showed relatively low resistivity compared to the undoped NiO thin films. In addition, the Na-doped NiO thin films deposited at room temperature showed the best properties, such as a p-type semiconducting with low electrical resistivity of $11.57{\Omega}.cm$ and high optical transmittance of ~80% in the visible light region. These results indicate that the Na doping followed by annealing process plays a crucial in enhancing the electrical and optical properties of NiO thin films. We believe that our results can be a good guide for those growing NiO thin films with the purpose of device applications, which require deposited at room temperature.

• 한국표면공학회지
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• 제51권2호
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• pp.87-94
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• 2018

Various sealing techniques were applied to the anodized 5083 aluminum alloy for marine environment to reduce corrosion and cavitation erosion damage. Electrochemical experiments and cavitation erosion tests were conducted to evaluate the corrosion resistance and cavitation resistance of the anodic oxide film treated with sealing in natural seawater solution. Then, damaged surface morphology was analyzed by scanning electron microscope(SEM) and 3D microscope. As the results of the electrochemical experiments, it was observed that the surface damage of all the experimental conditions in the anodic polarization experiment was locally grown by the combination of crack and corrosion damage. In the Tafel analysis, the corrosion resistance of all sealing treatment conditions was improved compared to the anodizing. On the other hand, cavitation erosion tests showed that the anodizing and all the sealing treatment conditions generated local pit damage by cavitation erosion attack and grew to crater damage in the observation of damaged surface by SEM. Also, the weight loss and the surface damage depth measured with the experiment time presented that most of the sealing treatment conditions showed better cavitation erosion resistance than the anodizing, and they had an incubation period at the beginning of the experiment.

• 대한한의학방제학회지
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• 제17권2호
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• pp.85-98
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• 2009

The fruits of Schisandra chinensis and Prunus mume have been traditionally used in the Oriental countries as an astringent against diarrhea and abdominal pain, a protectant for liver disease, an antimicrobial, and a blood tonic. However, little is known about the extract of Schizandrae Fructus and Mume Fructus (SMF-Ex) on dextran-sulfate sodium (DSS)-induced colitis in mice. In this study, we investigated the protective effects of SMF-Ex on DSS-induced colitis in mice. An experimental colitis was induced by daily treatment with 5% DSS. SMF-Ex was orally administrated the single dose (80 mg/kg, body weight/day) for 7 days with one time per day. SMF-Ex reduced significantly clinical sign of DSS-induced colitis, including body weight loss, shorten colon length, increased disease activity index (DAI), and histological colon injury. SMF-Ex also inhibited significantly nitric oxide (NO) and prostaglandine $E_2$ ($PGE_2$) productions in DSS-induced colitis mice. Furthermore, SMF-Ex increased significantly an superoxide anion (SOD), catalase, and glutathione peroxidase (Gpx) activity of the colon tissue in DSS-induced colitis mice. These results suggest that SMF-Ex administration could reduce significantly the clinical signs and inflammatory mediators, and increase antioxidant activity in DSS-induced colitis model mice and is a good candidate for further evaluation as an effective anti-ulcerative agent.

• 생약학회지
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• 제39권2호
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• pp.104-109
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• 2008

We previously reported that anti-inflammatory properties of poncirin, isolated from fruit of Poncirus trifoliata, might be the result from the inhibition of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis $factor-{\acute{a}}$ ($TNF-{\alpha}$) and interlukin-6 (IL-6) expression via the down-regulation of $NF{-\kappa}B$ binding activity. In this study, we investigated whether poncirin has an inhibitory effect on the production of pro-inflammatory mediators ex vivo and whether poncirin could relieve the symptoms of dextran sulfate sodium (DSS)-induced colitis in mice model of inflammatory bowel disease. Poncirin significantly inhibited the productions of NO, IL-6 and $TNF-{\alpha}$ in lipopolysaccharide (LPS)-induced mouse peritoneal macrophage. In addition, poncirin-treated mice when compared to control mice not receiving treatment recovered better from the weight loss caused by DSS-induced colitis. Changes in disease activity index (DAI) of poncirin-treated mice were also more favorable than for control mice and were comparable with mice treated with a typical anti-inflammatory-drug, 5-aminosalichylic acid (5-ASA). In addition, suppression of plasma NO and IL-6 productions of poncirin-treated mice was also observed in DSS-induced colitis. These results suggest that poncirin has potentially useful anti-inflammatory effects mediated by suppression of inflammatory mediator productions.