• 한국전기전자재료학회논문지
• /
• 제24권12호
• /
• pp.955-961
• /
• 2011

We investigated the physical properties of stoichiometric and non-stoichiometric oxide doped complex perovskite, $Ba(Zn_{1/3}Ta_{2/3})O_3$ ceramics and their impacts on the microwave dielectric performances using various characterization techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and network analyzer. According to the measurement of lattice constant changes, anomalous lattice volume contraction of $ZrO_2$ doped $Ba(Zn_{1/3}Ta_{2/3})O_3$ sample only showed the dielectric quality factor enhancements, which was due to the lattice volume contraction as well as the 1:2 B-site cation ordering. In addition, NiO doping was useful to the stabilization of temperature coefficient of resonance frequency.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 추계학술대회 논문집
• /
• pp.88-88
• /
• 2009

$BiFeO_3$(BFO), when forming a solid solution with $BaTiO_3$(BTO), shows structural transformations over the entire compositional range, which not only gives a way to increase structural stability and electrical resistivity but also applies a means to have better ferromagnetic ordering. In this respect, we have prepared and studied 0.7BFO-0.3BTO thin films on $Pt(111)/TiO_2/SiO_2/Si$ substrates by pulsed laser deposition. Various deposition parameters, such as deposition temperature and oxygen pressure, have been optimized to get better quality films. Based on the X-ray diffraction results, thin films were successfully deposited at the temperature of $600^{\circ}C$ and an oxygen partial pressure of 10mTorr. The dielectric, ferroelectric, and magnetic properties have then been characterized. It was found that the films deposited under lower oxygen pressure corresponded to lower leakage current. Magnetism measurement showed an induced ferromagnetism. The microstructures associated with. the magnetic and dielectric properties of this mixed-perovskite solid solutions were observed by transmission electron. microscopy, which revealed the existence of complicated ferroelectric domains, suggested that the weak spontaneous magnetization was closely associated with the decrease in the extent of rhombohedral distortion by a partial substitution of $BaTiO_3$ for $BiFeO_3$.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.139.1-139.1
• /
• 2016

Multiferroic materials are of great interest because of its potential applications in the design of devices combining magnetic, electronic and optical functionalities. Among various multiferroic materials, $BiFeO_3$(BFO) is known to be one of the intensively focused mainly due to the possibility of multiferroism at device working temperature (> $200^{\circ}C$). However, leakage current and weak polarization resulting from oxygen deficiency and crystalline defect should be resolved. Furthermore the magnetic ordering of pure BFO mainly prefers to have antiferromagnetic coupling. Up to now many attempts have been performed to improve the ferromagnetic and the ferroelectric properties of BFO by doping. In this work, we investigated the effects of Ni substitution on the multiferroism of bulk BFO. Four BFO samples (a pure BFO and three Ni-doped BFO's; $BiFe_{0.99}Ni_{0.01}O_3$, $BiFe_{0.98}Ni_{0.02}O_3$ and $BiFe_{0.97}Ni_{0.03}O_3$) were synthesized by the standard solid-state reaction and rapid sintering technique. The XRD results reveal that Ni atoms are substituted into Fe-sites and give rise to phase transition of cubic to rhombohedal. By using vibrating sample magnetometer and standard ferroelectric tester, the multiferroic properties at room temperature were characterized. We found that the magnetic moment of Ni-doped BFO turned out to be maximized for 3% of Ni dopant.

• 한국전자통신학회논문지
• /
• 제8권12호
• /
• pp.1875-1882
• /
• 2013

마이크로 어레이 기술은 유전자 네트워크의 순서 와 게놈의 통합과 같은 많은 업적을 기여하고 있으며, 이러한 기술은 유전자 발현의 패턴을 조사하기 위한 수단 등으로 잘 확립 되어있다. DNA 마이크로배열은 Affymetric 칩을 이용하여 대량의 DNA 서열을 합성 할 수 있는데 기존의 DNA 어레이 스포팅에는 일반적으로 접촉방식과 압전전자 방법등 두가지 유형이 있다. 접촉방법은 유리 슬라이드 표면과 접촉하도록 스포팅핀을 사용하는데 이 방법은 표면 매트릭스의 손상이나 상처가 발생할 수 있어 단백질이 오염 되거나 특정 결합을 방해할 위험이 있다. 반면에 압전전자 방법은 대량 생산이 가능함에도 불구하고 결과를 인쇄할 분석기가 필요하므로 현재 실험실 내에서만 수행 가능한 실정이다. 본 논문에서 유리 슬라이드 표면에 닿지 않고 지속적으로 일관성 있게 스포팅이 가능하도록 하는 진보된 방법을 제시한다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2010년도 하계학술대회 논문집
• /
• pp.313-313
• /
• 2010

$BiFeO_3$ (BFO), when forming a solid solution with $BaTiO_3$ (BTO), shows structural transformations over the entire compositional range, which not only gives a way to increase structural stability and electrical resistivity but also applies a means to have better ferromagnetic ordering. In this respect, we have prepared and studied 0.8 BFO-0.2 BTO thin films on Pt(111)/$TiO_2/SiO_2$/Si substrates by pulsed laser deposition. Various deposition parameters, such as deposition temperature and oxygen pressure, have been optimized to get better quality films. Based on the X-ray diffraction results, thin films were successfully deposited at the temperature of $700^{\circ}C$ and an oxygen partial pressure of 10mTorr and 330mTorr. The dielectric, ferroelectric, and magnetic properties have then been characterized. It was found that the films deposited under lower and higher oxygen pressure corresponded to lower leakage current. Magnetism measurement showed an induced ferromagnetism. The microstructures associated with the magnetic and dielectric properties of this mixed-perovskite solid solutions were observed by transmission electron microscopy, which revealed the existence of complicated ferroelectric domains, suggested that the weak spontaneous magnetization was closely associated with the decrease in the extent of rhombohedral distortion by a partial substitution of $BaTiO_3$ for $BiFeO_3$.

• 한국전기전자재료학회논문지
• /
• 제18권1호
• /
• pp.30-37
• /
• 2005

The microwave dielectric properties and their related structural characteristics in solid solutions of (1-$\chi$) Ba($Mg_{1/3}$Nb$_{2/3}$) $O_3$-$\chi$La(Mg$_{2/3}$Nb$_{1}$3) $O_3$(BLMN) have been investigated by measuring the dielectric constant($\varepsilon$r), Q value and temperature coefficient of resonant frequency($\tau$f) and by observing the crystal structure using high resolution transmission electron microscopy (HRTEM). Microwave dielectric properties showed characteristic features for specific composition. Dielectric constant($\varepsilon$$_{r}$) showed maximum value at the composition which corresponds to the phase boundary between 1 : 2 ordered and 1 : 1 ordered structure. The increase in $\varepsilon$$_{r}$ may be caused by the rattling of ions by incorporating smaller ions and the disordered structure. The variation of temperature coefficient of resonant frequency($\tau$$_{f}$) was investigated in terms of oxygen octahedra tilting.dra tilting.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.183-183
• /
• 2014

Recently, multiferroic materials gain much attention due to their fascinating fundamental physical properties. These materials offer wide range of potential applications such as data storage, spintronic devices and sensors, where both electronic and magnetic polarizations can be coupled. Among single-phase multiferroic materials, $BiFeO_3$ is typical because of the room-temperature magnetoelectric coupling in view of long-range magnetic- and ferroelectric-ordering temperatures. However, $BiFeO_3$ is well known to have large leakage current and small spontaneous polarization due to the existence of oxygen vacancies and other defects. Furthermore the magnetic moment of pure $BiFeO_3$ is very weak owing to its antiferromagnetic nature. Recently, various attempts have been performed to improve the multiferroic properties of $BiFeO_3$ through the co-doping at the A and the B sites, by making use of the fact that the intrinsic polarization and magnetization are associated with the lone pair of $Bi^{3+}$ ions at the A sites and the partially-filled 3d orbitals of $Fe^{3+}$ ions at the B sites, respectively. In this study, $BiFeO_3$, $Bi_{0.9}Ho_{0.1}FeO_3$, $BiFe_{0.97}Ni_{0.03}O_3$ and $Bi_{0.9}Ho_{0.1}Fe_{0.97}Ni_{0.03}O_3$ bulk compounds were prepared by solid-state reaction and rapid sintering. High-purity $Bi_2O_3$, $Ho_2O_3$, $Fe_2O_3$ and $NiO_2$ powders with the stoichiometric proportions were mixed, and calcined at $500^{\circ}C$ for 24 h to produce the samples. The samples were immediately put into an oven, which was heated up to $800^{\circ}C$ and sintered in air for 1 h. The crystalline structure of samples was investigated at room temperature by using a Rigaku Miniflex powder diffractometer. The field-dependent and temperature-dependent magnetization measurements were performed with a vibrating-sample magnetometer and superconducting quantum-interference device.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.260-260
• /
• 2013

Multiferroic materials have attracted much attention due to their fascinating fundamental physical properties and technological applications in magnetic/ferroelectric data-storage systems, quantum electromagnets, spintronics, and sensor devices. Among single-phase multiferroic materials, $BiFeO_3 $ is a typical multiferroic material with a room temperature magnetoelectric coupling in view of high magnetic-and ferroelectric-ordering temperatures (Neel temperature $T_N$~647 K and Curie temperature $T_C$~1,103 K). Rare-earth ion substitution at the Bi sties is very interesting, which induces suppressed volatility of Bi ion and improved ferroelectric properties. At the same time, Fe-site substitution with magnetic ions is also attracting, and the enhanced ferromagnetism was reported. In this study, $Bi_{1-x}Dy_xFe_{0.95}Co_{0.05}O_3$ (x=0, 0.05 and 0.1) bulk ceramic compounds were prepared by solid-state reaction and rapid sintering. High-purity $Bi_2O_3$, $Dy_2O_3$, $Fe_2O_3$ and $Co_3O_4$ powders with the stoichiometric proportions were mixed, and calcined at $500^{\circ}C$ or 24 h to produce $Bi_{1-x}Dy_xFe_{0.95}Co_{0.05}O_3$. The samples were immediately put into an oven, which was heated up to $800^{\circ}C$ nd sintered in air for 30 min. The crystalline structure of samples was investigated at room temperature by using a Rigaku Miniflex powder diffractometer. The field-dependent magnetization measurements were performed with a vibrating-sample magnetometer. The electric polarization was measured at room temperature by using a standard ferroelectric tester (RT66B, Radiant Technologies).

• 한국콘텐츠학회논문지
• /
• 제13권11호
• /
• pp.441-450
• /
• 2013

최근 토목분야 BIM(Building Information Modeling) 발주가 늘어남에 따라 발주처에서는 BIM 기반 성과품을 납품받고 있으나 관련지침 등이 미흡하고 작성방법, 수준, 성과품 목록 등이 구체적이지 않아 기존 2D기반의 성과품과 혼용해서 납품받고 있다. 이는 설계사나 시공사의 업무가중으로 연결될 수 있으며 관리해야 할 자료가 많아져 발주처에서도 부담으로 작용한다. 이러한 부담을 줄이기 위해서는 기존 2D 기반의 전자납품체계가 BIM발주체계로 전환될 경우 BIM모델에서 추출하여 활용하거나 대체가 가능한 2D기반의 성과품들을 조사하여 중복된 성과품을 최소화하는 작업이 필요하다. 이에, 본 연구에서는 국토교통부의 실시설계가 완료된 도로공사를 대상으로 BIM 모델링을 수행하였으며 이를 근간으로 총 3,767개 도면항목에 대해 2D도면 추출 가능여부를 검토하였다. 그 결과 67%인 2,549개의 도면항목이 BIM모델에서 2D도면으로 추출이 가능한 것으로 분석되었으며 특히 연결종합, 토공, 부대공 등과 관련된 도면항목들의 대체효과가 큰 것으로 조사되었다. 본 연구는 향후 BIM 관련 성과품 납품체계 개발시 2D 도면을 줄이거나 대체할 수 있는 근거자료로 활용될 수 있을 것이다.

• 한국콘텐츠학회논문지
• /
• 제8권12호
• /
• pp.20-27
• /
• 2008

현재 병원에서는 병원관리시스템(HIS), 의료영상시스템(PACS), 처방전달시스템(OCS), 전자의무기록(EMR), 전사적 자원관리(ERP) 등 각 과별 업무별로 독립적인 시스템을 사용하고 있으며, 각 시스템에 종속적인 각각의 DB를 운용하고 있다. 이에 따라 정보의 원내 통합이 불가능하며, 데이터의 투명성과 일관성을 유지하기 어려운 상황이다. 본 연구는 기존의 타 시스템과의 유연한 연계처리를 통한 데이터 통합환경을 제공하고, 이를 통해 고객이 원하는 최적의 서비스를 최적의 타이밍에 제공할 수 있는 의료 CRM 프레임을 설계하였다. 고객관리 프로세스 표준화에 의해 고객관리, 홍보/마케팅, 서비스관리, 통계/분석의 4가지 의료 CRM 프레임을 설계하였고 개인화된 의료정보 서비스 제공을 위한 모바일 의료 콘텐츠를 확보하여 고객 데이터를 바탕으로 고객의 특성과 건강 상황에 따라 맞춤형 모바일 콘텐츠를 제공할 수 있도록 설계하였다.