• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 2004년도 High Temperature Superconductivity Vol.XIV
• /
• pp.12-12
• /
• 2004

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2003년도 somma/kms meeting
• /
• pp.67-67
• /
• 2003

• 한국분말재료학회지
• /
• 제23권3호
• /
• pp.202-206
• /
• 2016

A Ni-Ti-B alloy powder prepared by mechanical alloying (MA) of individual Ni, Ti, and B components is examined with the aim of elucidating the phase transitions and crystallization during heat treatment. Ti and B atoms penetrating into the Ni lattice result in a Ni (Ti, B) solid solution and an amorphous phase. Differential thermal analysis (DTA) reveals peaks related to the decomposition of the metastable Ni (Ti, B) solid solution and the separation of equilibrium $Ni_3Ti$, $TiB_2$, and ${\tau}-Ni_20Ti_3B_6$ phases. The exothermal effects in the DTA curves move to lower temperatures with increasing milling time. The formation of a $TiB_2$ phase by annealing indicates that the mechanochemical reaction of the Ni-Ti-B alloy does not comply with the alloy composition in the ternary phase diagram, and Ti-B bonds are found to be more preferable than Ni-B bonds.

• 정보처리학회논문지B
• /
• 제10B권6호
• /
• pp.611-618
• /
• 2003

본 논문에서는 퍼지 추론 방법을 이용하여 비디오 데이터에서 샷(shot)의 경계를 검출하는 방법을 제안한다. 제안된 방법에서는 컷(cut), 페이드(fade), 디졸브(dissolve)와 같은 샷의 경계들을 검출하고, 이들을 그 종류별로 분류하기 위해 기본적으로 퍼지 연상 기억장치를 확장한 퍼지 추론 방법을 이용한다. 본 논문에서는 연속적인 두 영상 사이의 차이를 나타내는 여러 특징들을 입력 퍼지 집합으로 사용하고, 샷 경계들을 출력 퍼지 집합으로 사용한다. 본 논문의 퍼지 추론 시스템은 크게 학습 단계와 추론 단계의 두 단계로 구성된다. 학습 단계에서는 퍼지 소속 함수의 결정을 통해 시스템의 기본 구조를 초기화하고 이를 바탕으로 퍼지 연상 기억장치의 학습 기능을 이용하여 퍼지 규칙을 조건부와 결론부를 연결하는 가중치의 형태로 생성한다. 그리고 추론 단계에서는 구성된 퍼지 추론 모델을 이용하여 실제 추론을 수행한다. 실험에서는 제안된 샷 경계 검출 방법의 성능을 확인하기 위해서 뉴스, 영화, 광고, 다큐멘터리, 뮤직 비디오 등의 비디오 데이터들을 활용하였다.

• 한국자기공명학회논문지
• /
• 제26권1호
• /
• pp.10-16
• /
• 2022

The phase transition temperatures of CsCoCl₃·2H₂O crystals are investigated via differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Three endothermic peaks at temperatures of 370 K (=T_C1), 390 K (=T_C2), and 416 K (=T_C3) were observed for phase transitions from CsCoCl₃·2H₂O to CsCoCl₃·1.5H₂O, to CsCoCl₃·H₂O, and then to CsCoCl₃·0.5H₂O, respectively. In addition, the spin-lattice relaxation time T_1ρ in the rotating frame and T₁ in the laboratory frame as well as changes in chemical shifts for ¹H and ¹³³Cs near T_C1 were found to be temperature dependent. Our analyses results indicated that the changes of chemical shifts, T_1ρ, and T₁ are associated with structural phase transitions near temperature T_C1. The changes of chemical shifts, T_1ρ, and T₁ near T_C1 were associated with structural phase transitions, owing to the changes in the symmetry of the structure formed of H₂O and Cs⁺ ions. Consequently, the structural symmetry in CsCoCl₃·2H₂O crystals based on temperature is discussed by the environments of their H and Cs nuclei.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 하계학술대회 논문집 C
• /
• pp.1239-1243
• /
• 1997

A phase analysis in the solid solution of (1-x) PbFe1/2Nb1/2O3-xPbCo1/2W1/2O3 is conducted by dielectric properties, heat capacity and E-P hysteresis at x=0.1 interval. Lattice constants and superlattice intensity are analyzed by the x-ray diffraction, and the temperature - composition phase diagram is determined. The system is found to form a solid solution of perovskite structure throughout the entire composition range, but the nature of phase transitions changes from ferroelectric-paraelectric for $0{\leq}x{\leq}0.5$ to antiferroelectric-paraelectric for $0.6{\leq}x{\leq}1.0$. The transitions of ferroelectric-paraelectric and antiferroelectric-paraelectric for $0.2{\leq}x{\leq}0.5$ and for $0.6{\leq}x{\leq}0.8$, respectively, are diffuse, while those of the ferroelectric-paraelectric and the antiferroelectric-paraelectric for $0.0{\leq}x{\leq}0.1$ and $0.9{\leq}x{\leq}1.0$, respectively are sharp.

• Progress in Superconductivity
• /
• 제3권1호
• /
• pp.5-12
• /
• 2001

Our experimental research focuses on manipulating pinning deflects to alter the phase diagram of vortex matter, creating new vortex phases. Vortex matter offers a unique opportunity for creating and studying these novel phase transitions through precise control of thermal, pinning and elastic energies. The vortex melting transition in untwinned YB $a_2$C $u_3$ $O_{7-}$ $\delta$/ crystals is investigated in the presence of disorder induced by particle irradiation. We focus on the low disorder regime, where a glassy state and a lattice state can be realized in the same phase diagram. We follow the evolution of the first order vortex melting transition line into a continuous transition line as disorder is increased by irradiation. The transformation is marked by an upward shift in the lower critical point on the melting line. With columnar deflects induced by heavy ion irradiation, we find a second order Bose glass transition line separating the vortex liquid from a Bose glass below the lower critical point. Furthermore, we find an upper threshold of columnar defect concentration beyond which the lower critical point and the first order melting line disappear together. With point deflect clusters induced by proton irradiation, we find evidence for a continuous thermodynamic transition below the lower critical point..

• Current Applied Physics
• /
• 제18권11호
• /
• pp.1289-1293
• /
• 2018

The influence of crystallization treatment on the structure, magnetic properties and magnetocaloric effect of $Gd_{71}Ni_{29}$ melt-spun ribbons has been investigated in detail. Annealing of the melt-spun samples at 610 K for 30 min, a majority phase with a $Fe_3C$-type orthorhombic structure (space group, Pnma) and a minority phase with a CrB-type orthorhombic structure (space group, Cmcm) were obtained in the amorphous matrix. The amorphous melt-spun ribbons undergo a second-order ferromagnetic to paramagnetic phase transition at 122 K. For the annealed samples, two magnetic phase transitions caused by amorphous matrix and $Gd_3Ni$ phases occur at 82 and 100 K, respectively. The maximum magnetic entropy change $(-{\Delta}S_M)^{max}$ is $9.0J/(kg{\cdot}K)$ (5T) at 122 K for the melt-spun ribbons. The values of $(-{\Delta}S_M)^{max}$ in annealed ribbons are 1.0 and $5.7J/(kg{\cdot}K)$, corresponding to the two adjacent magnetic transitions.

• 대한화학회지
• /
• 제42권6호
• /
• pp.679-695
• /
• 1998

A series of ${\alpha}{\omega}-bis[4-(4'-(S)-(+)-2-methylbutylbiphenyl-4-carboxy)phenoxy]alkanes$, were synthesized, and their thermal and liquid crystalline properties were studied. The chain length of the central polymethylene spacers, x, of the chiral twin compounds was varied from 3 to 12. These compounds were characterized by elemental analysis, IR and NMR spectroscopy, differential thermal analysis (DSC), and crosspolarized microscopy. All compounds were found to be enantiotropic liquid crystalline, and the values of melting $(T_m)$ and isotropization temperature $(T_i)$ as well as ${\delta}H_I$ and ${\delta}S_I$ decreased in a zig-zag fashion, revealing the so called odd-even effect as x increased. Their mesomorphic properties fell into four categories depending upon x; (a) compounds with x=3, 4 and 5 formed only a cholesteric phase on heating, while on cooling they went through two transitions of isotropic (I)-to-cholesteric (Ch) and Ch-to-smectic $A\;(S_A)$ phases before crystallization. (b) compounds with x=6, 8 and 10 exhibited only a cholesteric phase both on heating and on cooling. (c) compounds with x=7 and 9 went through three transitions of crystal $(C)-to-S_A,\;S_A-to-Ch,$ and Ch-to-I phases on heating while on cooling they went through four transitions of I-to-Ch, $Ch-to-S_A,\;S_A-to-Smectic\;C\;(S_C),\;and\;S_c-to-C$ phases in that order, and (d) compounds with x=11 and 12 went reversibly through four transitions of $C-to-S_C,\;S_C-to-S_A,\;S_A-to-Ch,$ and Ch-to-I phases.

• 한국결정학회:학술대회논문집
• /
• 한국결정학회 2007년도 추계학술연구발표회 및 정기총회
• /
• pp.10-10
• /
• 2007