파괴인성 JIC 와 파단면에서 측정한 미세조도와의 상관 관계

오태성 대한금속재료학회(대한금속학회) 1995 대한금속·재료학회지 Vol.33 No.4

Correlations of the critical fracture strain ε_f and the fracture toughness J_(lc) with the microroughness measured on the fracture surfaces have been investigated for HP9-4-20 steel and ASTM A710 steel with different strength level. The critical fracture strain ε_f was proportional to the local microroughness (1/3)·ln(M²/3f_p) measured on the fracture surfaces. Fracture toughness J_(lc) was in good agreement with (σ_o/3)·ln(M²/3f_p)·l_o and could be estimated using the microroughness parameter M, the characteristic distance l_o, and the effective yield stress σ_o.

다층 박막 패키지 모듈의 제조 공정

오태성,김영호 대한전자공학회 1991 전자공학회지 Vol.18 No.4

발진부 귀환 스위칭회로를 이용한 이동통신 단말기용 듀얼대역 전압제어 발진기 특성에 관한 연구

오태성,이영훈 한국전자파학회 2002 한국전자파학회논문지 Vol.13 No.1

본 논문에서는 발진부 귀환경로에 스위칭소자를 이용하여 최소의 소자을 사용한 소형화된 새로운 방식의 이동통신 단말기용 듀얼대역 VCO(Voltage Control Oscillator)를 제안하였다. VCO에 공진기의 Q(Quality factor)값을 정확히 모델링하기 위하여 공진기를 등가 모델하고, 이론 수치 해석하여 최적의 공진기를 설계하였다. 본 논문에서 제안된 방식을 적용하여 GSM(Global System for Mobile), DCS(Digital Cordless System) 대역의 동작 주파수를 갖는 듀얼대역 전압제어 발진기를 설계하였으며, 논문의 객관성을 입증하기 위해 제작 및 실험을 통하여 새로 제안된 방식의 듀얼대역 전압제어 발진기의 실용화가 가능함을 확인하였고, 앞으로 차세대 이동통신 기기의 고주파 부품 등에 응용될 수 있을 것이다. In this paper, the dual band VCO of mobile communication terminal using oscillation part switching circuit is proposed. In order to model the VCO accurately, the resonator is converted the equivalent circuit which is analyzed to use numerical method and designed optimal the dual band VCO operating GSM and DCS band. In order to demonstrate the objective theory of the proposed VCO, the dual band VCO is designed and experimented. The results of experiment, it is conformed that the VCO can be used mobile communication hand phone and components of three generation mobile communication systems.

p형 Sb2Te3와 n형 Bi2Te3 열전박막의 전기도금공정을 이용한 마이크로 서모파일 센서의 형성공정 및 감지 특성 (초)

오태성,김민영,최정열 대한금속재료학회 ( 구 대한금속학회 ) 2008 대한금속재료학회 학술대회 개요집 Vol.2008 No.1

칼코지나이드계 Bi2Te3 및 PbTe 열전재료기술 (초)

오태성 대한금속재료학회 ( 구 대한금속학회 ) 2007 대한금속재료학회 학술대회 개요집 Vol.2007 No.1

PbTe 열전재료의 기계적 합금화 거동

오태성,최재식,현도빈,O, Tae-Seong,Choe, Jae-Sik,Hyeon, Do-Bin 한국재료학회 1995 한국재료학회지 Vol.5 No.2

Mechanical alloying behavior of the PbTe intermetallic compound, which is used for thermoelectric generation, has been investigated with milling time and ball-to-powder weight ratio. Formation of PbTe alloy was completed by mechanical alloying of the as-mixed Pb and Te powders for 2 minutes at ball-to-powder weight ratio of 2 : 1. In situ measurement of the abrupt temperature rise during the ball milling process indicated that the PbTe intermetallic compound was formed by a self-sustained reaction rather than diffusional reactions. Lattice constant of PbTe alloy fabricated by mechanical alloying, 0. 6462nm, was not varied with milling time and ball-to-powder weight ratio. This value of the lattice parameter is in excellent agreement with 0.6459nm, which was reported for PbTe powders processed by melting and grinding. 열전발전용 재료인 PbTe의 밀링 시간, 볼과 분말의 무게비에 따른 기계적 합금화 거동을 연구하였다. Pb와 Te 분말을 볼과 분말의 무게비 2 : 1에서 2분간 기계적 합금화 함으로써 PbTe 금속간 화합물의 형성이 완료되었다. 밀링 공정중 vial 표면 온도의 in situ 측정에서 기계적 합금화에 의한 PbTe 금속간 화합물의 형성이 분말 계면에서의 확산 공정보다는 합금화 반응이 자발적으로 전파하는 자전 반응에 의하여 이루어지는 것을 알 수 있었다. 기계적 합금화로 제조한 PbTe 합금분말의 격자상수는 0.6462nm로 용해 및 분쇄법으로 제조한 PbTe 분말에서 보고된 값인 0.6459nm와 잘 일치하였으며, 밀링 시간의 증가 및 볼과 분말의 무게비의 변화에 의하여 변하지않았다.

Flip-Chip Process using Heat Transfer from an Induction-Heating Film

오태성,이광용,이윤희,정부양 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.3

A new flip-chip technology to attach an IC chip directly to a substrate was studied using the heat transfer from an induction-heating film in an AC magnetic field. When applying a magnetic field of 230 Oe at 14 kHz, the temperature of a 600 μm-thick 5 mm × 5 mm Cu induction-heating film reached 250 °C within 60 s. The temperature of the glass substrate used in this process was kept below 118 °C at a distance of 1,350 μm from the Cu induction-heating film, which was maintained at 250 °C, implying that damage to a substrate can be minimized with the flip-chip process using heat transfer from an induction-heating film. Flip-chip bonding was successfully accomplished with the reflow of Sn-3.5Ag solder bumps by applying a magnetic field of 230 Oe at 14 kHz for 120 s to a Cu induction-heating film. A new flip-chip technology to attach an IC chip directly to a substrate was studied using the heat transfer from an induction-heating film in an AC magnetic field. When applying a magnetic field of 230 Oe at 14 kHz, the temperature of a 600 μm-thick 5 mm × 5 mm Cu induction-heating film reached 250 °C within 60 s. The temperature of the glass substrate used in this process was kept below 118 °C at a distance of 1,350 μm from the Cu induction-heating film, which was maintained at 250 °C, implying that damage to a substrate can be minimized with the flip-chip process using heat transfer from an induction-heating film. Flip-chip bonding was successfully accomplished with the reflow of Sn-3.5Ag solder bumps by applying a magnetic field of 230 Oe at 14 kHz for 120 s to a Cu induction-heating film.

n형 Bi₂(Te0.85Se0.15)₃가압소결체의 열전특성

吳泰成 弘益大學校 科學基術硏究所 1999 科學技術硏究論文集 Vol.10 No.2

Thermoelectric properties of the hot-pressed Bi₂(Te??Se) alloy, prepared by mechanical alloying and melting/grinding methods, were investigated with the variation of the hot-pressing temperature ranging from 300℃ to 550℃. Contrary to the p-type behavior of the undoped Bi₂(Te??Se??) single crystal, the hot-pressed Bi₂(Te??Se??) alloy exhibited n-type conduction without addition of donor dopant. Compared to value of the specimen hot-pressed with the mechanically alloyed powders, higher figure-of-merit was obtained for the specimens prepared with melting/grinding method. When hot-pressed at 550℃, the Bi₂(Te??Se??) alloy, prepared by mechanical alloying and melting/grinding, exhibited the figure-of-merits of 1.92×10??/K and 2.28×10??/K, respectively.

미세 열에너지 하비스팅용 열전박막소자의 형성공정 및 발전특성

오태성 한국마이크로전자및패키징학회 2018 마이크로전자 및 패키징학회지 Vol.25 No.3

Thermoelectric thin film devices of the in-plane configuration consisting of 8 pairs of n-type Bi2Te3 and ptype Sb2Te3 legs were processed on Si submounts by electrodeposition. The thermoelectric generation characteristics of the thin film devices were investigated with respect to the apparent temperature difference ΔT caused by LED lighting as well as the change of the leg thickness. When ΔT was 7.4 K, the open circuit voltages of 6.1 mV, 7.4 mV, and 11.8 mV and the maximum output powers of 6.6 nW, 12.8 nW, and 41.9 nW were measured for the devices with the thermoelectric legs of which thickness were 2.5 μm, 5 μm, and 10 μm, respectively. 두께 2.5~10 μm인 n형 Bi2Te3와 p형 Sb2Te3 레그 8쌍으로 구성되어 있는 in-plane형 열전박막소자를 전기도금법으로 Si submounts에 형성하고, LED 칩의 구동에 의해 발생하는 겉보기 온도차 ΔT와 레그 두께에 따른 발전특성을분석하였다. LED 방출열에 의해 인가된 ΔT가 7.4K일 때 각기 두께 2.5 μm, 5 μm 및 10 μm의 p-n 레그들로 구성된 열전박막소자는 6.1 mV, 7.4 mV 및 11.8 mV의 open circuit 전압을 나타내었으며, 6.6 nW, 12.8 nW 및 41.9 nW의 최대 출력전력을 나타내었다.

생체활성 Ti-수산화 아파타이트 복합재료의 소결 특성

吳泰成 弘益大學校 科學技術硏究所 1994 科學技術硏究論文集 Vol.5 No.-

Sintering characteristics and mechanical properties of HAP/Ti composites have been investigated with variations of the powder processing method. Ti volume fraction, and sintering temperature. HAP/Ti composite powders were fabricated either by mechanical alloying, or mechanical milling and mixing processes of hydroxylapatite and Ti powders. With complete broadening of X-ray diffraction peaks of HAP/Ti powders by mechanical alloying for 10 hours, it could be suggested that reactions between HAP and Ti occurred during mechanical alloying process. For HAP/Ti composites processed by mechanical milling and sintered at 1100℃ for 4 hours, fracture toughness ??? and MOR decreased with Ti volume fraction in HAP/Ti composites due to the crack propagation along the poorly sintered Ti-rich phases. For HAP/Ti composites fabricated by mechanical alloying and sintered at 1300℃ for 4 hours, fracture toughness and MOR incerased with Ti volume fraction, and ??? of ??????????? and MOR of 50 MPa could be obtained for 80HAP/20Ti composite.