• 한국반도체및디스플레이장비학회:학술대회논문집
• /
• 한국반도체및디스플레이장비학회 2003년도 추계학술대회 발표 논문집
• /
• pp.163-168
• /
• 2003

In the present study, the piezoelectricity and polarization of multilayer ceramic actuator, being designed to stack PMN-PZ-PT ceramic layers and Ag-Pd electrode layers alternatively, were investigated under a consideration of geometric factor, the volume ratio of the ceramic to the electrode layers. The actuators were fabricated by tape casting of $0.2Pb(Mg_{1/3}Nb_{2/3)O_3-0.38PbZrO_3-0,42PbTiO_3$ followed by lamination and burnout & co-firing processes. The actuators of $10\times10\times0.6~2\textrm{mm}^3$ in size were formed in a way that $60 ~ 200\mu\textrm{m}$ thick were stacked alternatively with $5\mu\textrm{m}$ thick electrode layer. Increases in polarization and electric field-induced displacement with thickness of the ceramic layer were attributed to change of $90^{\circ}$/$180^{\circ}$ domain ratio, which was affected by interlayer internal stress. The piezoelectricity and actuation behaviors were found to depend upon the volume ratio (or thickness ratio) of ceramic to electrode layers.

• Journal of Magnetics
• /
• 제14권3호
• /
• pp.114-116
• /
• 2009

The electronic properties of Cu or Pd-doped GaN at several concentrations are examined using the full-potential linear muffin-tin orbital method. For ($Cu_{0.055}Ga_{0.945}$)N, the model reveals a magnetic moment of $1.47{\mu}B$ per supercell. The range of concentrations that are spin-polarized should be restricted within narrow limits. A paramagnetic to ferromagnetic phase transition is found to occur at a Cu concentration of 5.55%.

• 한국진공학회지
• /
• 제4권S2호
• /
• pp.75-78
• /
• 1995

Gas source molecular beam epitaxy have been used in the growth of InAlAsAnGaAs MSM-PD structure, in which InAlAs ultra thin layer was used as Schottky barrier enhancement material. High performance MSM-PDs have been constructed on the grown wafer. High breakdown voltage of >30V, low dark current density of $3pA/\mu \textrm{cm}^2$ at 10V bias and fast transient response of <20ps rise time / <40ps FWHM have been measured, which confirm the results that GSMBE is a superior method for the growth of materials with high layer and interfacial quality, especially for InP based InAIAdInGaAs system.

• Bulletin of the Korean Chemical Society
• /
• 제22권11호
• /
• pp.1183-1191
• /
• 2001

The metallorganic chemical vapor deposition (MOCVD) method has been used to prepare TiO2 thin films for the degradation of hazardous organic compounds, such as 2-chlorophenol (2-CP). The effect of supporting materials and metal doping on the photocatalytic activity of TiO2 thin films also has been studied. TiO2 thin films were coated onto various supporting materials, including stainless steel cloth(SS), quartz glass tube (QGT), and silica gel (SG). Transition metals, such as Pd(II), Pt(IV), Nd(III) and Fe(III), were doped onto TiO2 thin film. The results indicate that Nd(Ⅲ) doping improves the photodegradation of 2-CP. Among all supporting materials studied, SS(37 ${\mu}m)$ appears to be the best support. An optimal amount of doping material at 1.0 percent (w/w) of TiO2-substrate thin film gives the best photodegration of 2-CP.

• 한국전기전자재료학회논문지
• /
• 제13권11호
• /
• pp.921-925
• /
• 2000

Characteristics of Pb(Mg, Nb)O$_3$-Pb(Zr, Ti)O$_3$system thick films fabricated by a screen printing method were investigated. The buffer layer were coated with various thickness of Ag-Pd by screen printing to investigate the effect as a diffusion barrier and deposited Pt as a electrode by sputtering on Ag-Pb layer. The printed thick films were burned out at 650$\^{C}$ and sintered at 950$\^{C}$ in O$_2$condition for each 20, 60min after printing with 350mesh screen. The thickness of piezoelectric thick film was 15∼20㎛ and Ag-Pb layer acted as a diffusion barrier above 3㎛ thickness. The PMN-PZT thick films were screen printed on Pt/Ag-Pb(6m) and sintered by 2nd step (650$\^{C}$/20min and 950$\^{C}$/1h) using paste mixed PMN-PZT and binder in the ratio of 70:30, and the remnant polarization of thick film was 9.1$\mu$C/㎠ in this conditions.

• 대한건축학회논문집:계획계
• /
• 제35권12호
• /
• pp.115-125
• /
• 2019

Most of construction at urban area is now undertaking a redevelopment because currently the most of city is full. But the research about the collision of urban tissue at urban redevelopment area are very limited and there are many issues at urban redevelopment area. So the purpose of this study is to analyze the collision between different urban tissue at urban redevelopment area and suggest proper method for urban redevelopment. The area inside of four main gates, especially Chung Jin, Gong pyeong, Mu gyo- Da dong district are selected to analyze because the area inside of these gates is the oldest urban redevelopment area and each of them has a different redeveloped method. And current status of research area's urban tissue and collision situation are analyzed by macro and micro scale of view. The results of this study were as follows; Ignoring the timeline of the urban redevelopment process can be a major issue in collision between urban tissue. Therefore, the consideration of intermediate stage of redevelopment process is needed by making public area, a temporal use of vacant lot and changing architectural elements can make a harmony between different urban tissue.

• 대한화학회지
• /
• 제38권11호
• /
• pp.827-832
• /
• 1994

(N-methylphenazinium) bis(oxalato)palladate(II)$((C_{13}H_{11}N_2)_2[Pd(C_2O_4)_2])$의 착이온 및 결정의 구조는 X-선 회절법으로 연구하였다. 이 결정은 사방정계이고 공간군은 P1 (군번호 = 2)이다. 단위세포 길이는 a = 7.616(8), b = 9.842(3), c = $20.335(7)\AA$, $\alpha$ = 103.53(3), $\beta$ = 90.00(5), $\gamma$ = $112.38(5)^{\circ}이며$, $V = 1363(2){\AA}^3,\;F_w = 672.93,\;D_c = 1.639\;gcm^{-3},\;F(000) = 680.0,\;{\mu} = 7.3\;cm^{-1},\;Z = 2$이다. 회절반점들의 세기는 흑연 단색화 장치가 있는 자동 4축 회절기로 얻었으며 $Mo-K\alpha$ X - 선(${\lambda}$= 0.7107 $\AA)$을 사용하였다. 구조분석은 중금속법으로 풀었으며, 최소자승법으로 정밀화하였고, 최종 신뢰도 값들은 3120개의 회절반점에 대하여 $R = 0.069,\;R_w = 0.050,\;R_{all} = 0.069$ 및 S = 5.45였다. 착이온들은 근본적인 평면구조로써, 이들의 충진구조는 착음이온들을 두개의 양이온들이 거의 평행하게 둘러싸고 있는 삼중체들을 형성하고 있다. 양이온과 음이온들의 이면각들이 각각 6.3(6)과 $57.06(6)^{\circ}$인 삼중체들이 b축을 따라서 배열되어 있으나, 삼중체면의 배향은 두 가지 착음이온의 이면각이 $59.08(9)^{\circ}$을 이루는 방향이다. 삼중체내의 면간거리는 각각 3.328와 3.463 $\AA$이었다.

• 분석과학
• /
• 제15권3호
• /
• pp.263-269
• /
• 2002

평균입경이 200 ${\mu}m$인 코디어라이트 분말로 다공성 필터를 제조한 후, 진공함침법으로 Pt, Pd, Cu, Co, La, $V_2O_5$ 촉매를 담지시켰다. VOC의 일종인 톨루엔을 촉매담지 세라믹필터에 통과시키며 촉매산화시킴으로서 톨루엔에 대한 촉매들의 활성에 대하여 고찰하였다. 제조된 다공성 필터의 겉보기 기공률은 62%였고, 압축강도는 약 10 MPa이었으며, 5 cm/sec 유속에서의 차압은 15 mmHg였다. 촉매를 필터에 담지시키면 기공률은 감소하고, 차압과 압축강도는 증가하였다. 필터에 담지된 촉매들 중에서 Pt 촉매의 활성이 가장 높았고, 250 $^{\circ}C$의 온도에서 90% 이상의 톨루엔을 제거시킬 수 있었다. 250 $^{\circ}C$ 이하의 온도에서는 Pt 촉매 담지량이 톨루엔의 전환율에 영향을 미쳤지만, 그 이상의 온도에서는 Pt 촉매 담지량의 차이에 의한 영향은 나타나지 않았다.

• Clinical and Experimental Reproductive Medicine
• /
• 제33권2호
• /
• pp.105-113
• /
• 2006

목 적: 본 연구를 통해 $TGF-{\beta}1$에 의해 유도된 인간자궁내막의 탈락막화 과정에서 ERK와 $PPAR{\gamma}$의 역할을 규명하고자 하였다. 연구방법: 자궁내막 기질세포는 DMEM/F12 (10% FBS, 1 nM E2 and 100 nM P4) 조건에서 배양하였다. 연구 목적에 따라 $TGF-{\beta}1$ (5 ng/ml), Rosiglitazone (50 nM)와 PD98059 ($20{\mu}M$)를 배양액에 첨가하였다. Trypan-Blue와 hematocytometer를 이용하여 현미경하에서 세포의 개수를 측정하였다. Enzyme-linked immunosorbent assay (ELISA)와 western blotting 방법을 사용하여 단백질의 발현 정도를 관찰하였다. 결과 및 결론: 배양액에 $TGF-{\beta}1$을 첨가하여 세포의 증식 정도를 측정한 결과 $TGF-{\beta}1$이 세포의 증식을 억제하는 것을 알 수 있었다. 또한 배양된 세포로부터 PGE2 및 prolactin의 발현을 유도하는 것을 알 수 있었다. 이러한 $TGF-{\beta}1$의 작용은 Smad 및 ERK의 활성화를 통하여 일어남을 알 수 있었다. $PPAR{\gamma}$의 기질인 rosiglitazone을 배양액에 첨가한 결과 $TGF-{\beta}1$에 의한 세포 증식의 억제가 역전되는 것을 알 수 있었다. 뿐만 아니라, 세포 내 ERK의 활성 역시 억제 시켰으며 이 결과 PGE2와 prolactin의 발현이 억제 되는 것을 관찰할 수 있었다. 따라서 본 연구를 통해 $TGF-{\beta}1$에 의한 자궁내막 기질세포의 탈락막화는 Smad와 ERK의 활성화를 통하여 이루어지며 이러한 과정은 $PPAR{\gamma}$에 의해 억제됨을 알 수 있었다.

• Journal of Ginseng Research
• /
• 제38권3호
• /
• pp.173-179
• /
• 2014

Background: Ginsenosides are the major components responsible for the biochemical and pharmacological actions of ginseng, and have been shown to have various biological activities. In this study, we investigated the antiviral activities of seven ginsenosides [protopanaxatriol (PT) type: Re, Rf, and Rg2; protopanaxadiol (PD) type: Rb1, Rb2, Rc, and Rd)] against coxsackievirus B3 (CVB3), enterovirus 71 (EV71), and human rhinovirus 3 (HRV3). Methods: Assays of antiviral activity and cytotoxicity were evaluated by the sulforhodamine B method using the cytopathic effect (CPE) reduction assay. Results: The antiviral assays demonstrated that, of the seven ginsenosides, the PT-type ginsenosides (Re, Rf, and Rg2) possess significant antiviral activities against CVB3 and HRV3 at a concentration of $100{\mu}g/mL$. Among the PT-type ginsenosides, only ginsenoside Rg2 showed significant anti-EV71 activity with no cytotoxicity to cells at $100{\mu}g/mL$. The PD-type ginsenosides (Rb1, Rb2, Rc, and Rd), by contrast, did not show any significant antiviral activity against CVB3, EV71, and HRV3, and exhibited cytotoxic effects to virus-infected cells. Notably, the antiviral efficacies of PT-type ginsenosides were comparable to those of ribavirin, a commonly used antiviral drug. Conclusion: Collectively, our findings suggest that the ginsenosides Re, Rf, and Rg2 have the potential to be effective in the treatment of CVB3, EV71, and HRV3 infection.