• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.738-743
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• 2004

The microwave dielectric properties and their related structural characteristics in solid solutions of (1-x) $Ba(Mg_{1/3}Nb_{2/3})O_3$ -x $La(Mg_{2/3}Nb_{1/3})O_3$ (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.

• Asia pacific journal of information systems
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• 제14권1호
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• pp.59-77
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• 2004

Even though B2B EC is becoming popular, there have been not so much studies about performance evaluation methodology for B2B systems. In this paper, after analyzing buyer-carts systematically focusing on the buyer's interactional efforts on the typical buying processes of each buyer-cart, we propose a quantitative performance evaluation model. For this, we categorize buyer-carts in B2B EC as s-cart, i-cart, and b-cart depending upon its residing sites: seller, intermediary, and buyer sites. And after proposing the desired features of buyer-carts in B2B EC as identification, collection, trashing, ordering, payment, tracking, recording, purchasing decision support, and transmission of records to e-procurement systems, we derive a performance evaluation model by calculating detail sub-processes from the desired features' viewpoints. By setting variables from a survey on the actual condition of using buyer-carts in companies in Korea, we try to evaluate the performance of buyer-carts in B2B EC. In this paper, we suggest a new methodology of performance evaluation for B2B systems, and show that the b-cart platform is more efficient than other buyer-carts especially in B2B EC.

• Journal of Magnetics
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• 제20권4호
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• pp.331-335
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• 2015

The ferromagnetic and electronic structure for the $Al_xGa_{1-x}P$ and Mn-doped $AlGaP_2$ was studied by using the self-consistent full-potential linear muffin-tin orbital method. The lattice parameters of un-doped $Al_xGa_{1-x}P$ (x = 0.25, 0.5, and 0.75) were optimized. The band-structure and the density of states of Mn-doped $AlGaP_2$ with or without the vacancy were investigated in detail. The P-3p states at the Fermi level dominate rather than the other states. Thus a strong interaction between the Mn-3d and P-3p states is formed. The ferromagnetic ordering of dopant Mn with high magnetic moment is induced due to the (Mn-3d)-(P-3p)-(Mn-3d) hybridization, which is attributed by the partially filled P-3p bands. The holes are mediated with keeping their 3d-characters, therefore the ferromagnetic state is stabilized by this double-exchange mechanism.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.88-92
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• 2002

$Ba(Zn_{0.8}Co_{0.2})_{1/3}Ta_{2/3}O_3$ [BZCT(80/20)] ceramics were prepared by the conventional mixed oxide method. The ceramics were sintered at the temperature of $1450{\sim}1550^{\circ}C$ for 5hr. in air. The structural properties of BZCT(80/20) ceramics were investigated as a function of sintering temperature. The BZCT(80/20) ceramics sintered at $1550^{\circ}C$ showed a polycrystalline complex perovskite structure without second phases and any unreacted materials. Increasing the sintering temperature, the bulk density and ordering were increased. The bulk density of the BZCT(80/20) ceramics sintered at $1550^{\circ}C$ was 7.50[$g/cm^2$]. Increasing the sintering temperature, the average grain size were increased and pore were decreased.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.383-386
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• 2000

The 0.6Ba(Zn$_{1}$3/Ta$_{2}$3/)O$_3$-0.4Ba(Co$_{1}$3/Nb$_{2}$3/)O$_3$ceramics were prepared by the conventional mixed oxide method. The structural properties of the 0.6BZT-0.4BCN ceramics with the sintering temperature were investigated by XRD, SEM. The 0.6BZT-0.4BCN ceramics had a complex-perovskite structure. Increasing the sintering temperature, the peak intensity of the superstructure reflection plane were increased and the density and ordering were increased. The density of the 0.6BZT-0.4BCN ceramics sintered at 1475$^{\circ}C$ was 6.455[g/cm$^3$].

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.283-287
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• 2003

Crystal structure of $(Ba_{1-x}La_x)[Mg_{(1+x)/3}Nb_{(2-x)/3}]O_3$ (BLMN) ceramics with $0{\leq}x{\leq}1$ was investigated using synchrotron X-ray powder diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). When La content, x, is above 0.1, the 1:2 ordered hexagonal structure found in $Ba(Mg_{1/3}Nb_{2/3})O_3$ (BMN) was transformed into 1:1 ordered cubic structure. The 1:1 ordered cubic structure was maintained up to x=0.7. However, when x exceeded 0.7, BLMN was transformed 1:1 ordered structure which has cation displacement and in-phase and anti-phase tilt of octahedra.

• 한국전기전자재료학회논문지
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• 제17권7호
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• pp.718-723
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• 2004

Crystal structure of $(Ba-{1-x}La_x)[Mg_\frac{1+x}{3}}Nb_\frac{{2-x}{3}}]O_3$ (BLMN) ceramics with 0\leq1x \geq was investigated using synchrotron X-ray powder diffraction (XRD) and high reso(B $a_{l-x}$L $a_{x}$)[M $g_{(1+x)}$3/N $b_{(2-x)/3}$］ $O_3$lution transmission electron microscopy (HRTEM). When the La content, x, is above 0.1, the 1:2 ordered hexagonal structure found in Ba($Mg_\frac{1}{3}Nb_\frac{2}{3}})O_3$(BMN) was transformed into 1:1 ordered cubic structure. The 1:1 ordered cubic structure was maintained up to x=0.7. When x exceeded 0.7, however, BLMN was transformed into 1:1 ordered structure which has cation displacement and in-phase and anti-phase tilt of octahedra.

• 한국자기학회지
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• 제9권3호
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• pp.131-135
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• 1999

층상 페로브스카이트형 구조를 가진 망간 산화물의 전자구조를 이해하기 위하여 단일 층상을 가진 LaSrMnO4의 전자구조를 제1원리의 국소 밀도 범함수 이론을 근거로 사용하는 Full Potential Linearized Augmented Plane Wave(FLAPW)방법으로 구하였다. 또한 홀 농도 변환에 따른 자기구조의 변화의 이해를 위해 Mn4+의 Sr2MnO4의 전자구조 계산을 행하여 전자구조를 비교하였다. 총에너지 계산 결과, LaSrMnO4는 면내의 반강자성 구조가 강자성 구조보다 더 낮은 에너지를 가지고 있었다. 또한, Mn-O 팔면체의 c축으로의 야안-텔러 왜곡(Jahn-Teller distortion)에 의해 에너지 갭이 나타나며, 이에 따른 3z2-r2 궤도 정렬에 의해 2차원 면내의 반강자성 상태가 안정됨을 볼 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.318.2-318.2
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• 2016

FeM2X4 spinel structures, where M is a transition metal and X is oxygen or sulfur, are candidate materials for spin filters, one of the key devices in spintronics. Both the Fe and M ions can occupy tetrahedral and octahedral sites; therefore, these types of compounds can display various physical and chemical properties [1]. On the other hand, the electronic and magnetic properties of these spinel structures could be modified via the control of cation distribution [2, 3]. Among the spinel oxides, iron manganese oxide is one of promising materials for applications. FeMn2O4 shows inverse spinel structure above 390 K and ferrimagnetic properties below the temperature [4]. In this work, we report on the structural and magnetic properties of epitaxial FeMn2O4 thin film on MgO(100) substrate. The reflection high energy electron diffraction (RHEED) and X-ray diffraction (XRD) results indicated that films were epitaxially grown on MgO(100) without the impurity phases. The valance states of Fe and Mn in the FeMn2O4 film were carried out using x-ray photoelectron spectrometer (XPS). The magnetic properties were measured by vibrating sample magnetometer (VSM), indicating that the samples are ferromagnetic at room temperature. The structural detail and origin of magnetic ordering in FeMn2O4 will be discussed.

• 대한전자공학회논문지SD
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• 제46권7호
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• pp.22-28
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• 2009

멀티프로세서가 임베디드 시스템에서 널리 쓰임에 따라 지원되는 전력 최소화 기법을 이용하여 태스크를 수행하기 위해 필요한 에너지의 소모량을 줄여야 할 필요성이 대두된다. 본 논문은 동적 전압 스케일링 및 전력 셧다운을 이용하여 에너지 소모를 최소화 하는 태스크 스케줄링 알고리즘을 멀티프로세서 환경을 위해 제안하였다. 제안된 알고리즘에서는 전력 셧다운시의 에너지 및 타이밍 오버헤드를 고려하여 반복적으로 태스크 할당 및 태스크 순서화를 수행한다. 제안된 반복적인 태스크 스케줄링을 통해 전체 에너지 소모를 줄이는 가장 좋은 해를 얻을 수 있었다. 전체 에너지 소모는 리니어 프로그래밍 모델 및 전력 셧다운의 임계 시간을 고려하여 계산되었다. 실제 어플리케이션으로부터 추출된 표준 태스크 그래프에 기반을 둔 실험 결과를 통해 하드웨어 자원 및 시간제한에 따른 에너지 소모 관계를 분석하였다. 실험 결과를 볼 때 제안된 알고리즘은 기존의 우선권 기반의 태스크 스케줄링에 대해서 의미 있는 성능 향상을 얻을 수 있었다.