• 한국표면공학회지
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• 제38권2호
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• pp.83-87
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• 2005

We enhanced the color of blue sapphires and rubies successfully by using a oxygen-propane torch flame annealing, which had not been employed so far. We confirmed that about 1 mm-thick de-coloring of the corundum samples were available with 60 minutes flame annealing through eye evaluation, color coordination characterization, and methylene iodide immersion observation. We also suggest that the color centers such as $[Fe_{Al}^{\cdot}]$ may transform into transparent $[Fe_{Al}^{x}],\;[Cr_{A1}^{x}]$ sites with $[V_o^']$ generation at the elevated temperature in oxygen-rich atmosphere by diffusion mechanism. Our results implied that the longer diffusion time and the higher oxygen partial pressure might lead to the better de-coloring enhancement in corundum gem stones.

• 한국포장학회지
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• 제24권2호
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• pp.41-48
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• 2018

본 연구에서는 산소지시물질을 이용한 새로운 UV-activation 인쇄형 시간-온도 이력지시계(time temperature integrator; TTI)를 개발하였다. $TiO_2$와 glycerol이 UV activation을 위해서 첨가되었으며 glycerol의 경우 비가역적반응을 위해 첨가량을 23 mg으로 조절하였다. 또한 인쇄적성을 위해 zein 함량 0.8 g, 90% ethanol 함량 4.0 g으로 조절하였고 silk screen의 mesh는 250 mesh일 때 최적의 인쇄성상을 나타내었다. 서로 다른 커버필름(PE, PET, OPP, and LLDPE)을 이용하여 색변화속도와 온도의존성을 측정하였다. 각 필름의 $E_a$를 측정한 결과 OPP, PE, LLDPE의 경우 60.07-84.47 kJ/mol의 $E_a$를 나타내어 TTI로서의 적용가능성을 확인할 수 있었다. 반면 PET의 경우 $E_a$가 15.76 kJ/mol으로 적용성이 떨어지는 것으로 판단되었다. 또한 커버필름의 두께의 경우 $E_a$에 영향을 미치지 않는 것으로 나타났으며 annealing한 필름은 고분자 구조의 변화로 인해 산소 투과도가 annealing하지 않은 동종의 필름보다 PET의 경우 29.8%, PVC의 경우 60.7% 감소하는 것으로 나타났다. 본 연구에서 새롭게 개발된 UV-activation 인쇄형 TTI는 다양한 커버필름을 통해 산소 투과도와 $E_a$를 조절할 수 있었고 annealing을 통하여 추가적으로 산소 투과도를 조절할 수 있어 다양한 유효기간을 갖는 식품에 광범위하게 사용될 수 있을 것으로 기대된다.

• Progress in Superconductivity
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• 제4권2호
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• pp.176-179
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• 2003

A lot of efforts have been focused on the optimization of PIT parameters for Bi-2223/Ag wire. Bi-2223 superconducting wires with 55 filaments were fabricated by stacking, drawing process. Before rolling process, round wires were pre -annealed at 760 - 820 $^{\circ}C$ and low oxygen partial pressure. We confirmed that pre-annealing step was to transform Bi-2212 orthorhombic structure from Bi-2212 tetragonal structure and to reduce the formation of second phases. However Bi-2223 phases also were formed at higher than 76$0^{\circ}C$ of pre-annealing temperature. The engineering critical current densities (Je) of Bi-22231Ag tapes were sintered at low oxygen partial pressure were higher than t hat of the wires sintered at air. We could achieve 6500 A/${cm}^2$ of Je for the tape that was initially kept at slightly higher temperature than that of normal heat treatment.

• 한국재료학회지
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• 제15권9호
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• pp.555-559
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• 2005

An oxygen free copper severely-deformed by eight cycles (an equivalent strain of $\~6.4$) of accumulative roll-bonding (ARB) was annealed at various temperatures ranging from 100 to $300^{\circ}C$. The annealed copper was characterized by transmission electron microscopy (TEM) and tensile & hardness test. TEM observation revealed that the ultrafine grains developed by the ARB still remained up to $150^{\circ}C$, however above $200^{\circ}C$ they were replaced by equiaxed and coarse grains due to an occurrence of the static recrystallization. Tensile strength and hardness of the copper decreased slightly with the annealing temperature up to $150^{\circ}C$, however they dropped largely above $200^{\circ}C$. Annealing characteristics of the copper were compared with those of a commercially pure aluminum processed by ARB and subsequently annealed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1627-1630
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• 2004

ZnO thin films on (001) sapphire substrates have been deposited by pulsed laser deposition(PLD) technique using an Nd:YAG laser with a wavelength of 266nm. Before post-annealing treatment in the oxygen ambient, the experiment of the deposition of ZnO thin films has been performed for substrate temperatures in the range of $300{\sim}450^{\circ}C$ and flow rate of 100${\sim}$700 seem. In order to investigate the effect of post-annealing treatment of ZnO thin films, films have been annealed at various temperatures after deposition. After post-annealing treatment in the oxygen ambient, the structural properties of ZnO thin films were characterized by X-ray diffraction(XRD) and the optical properties of the ZnO were characterized by photoluminescence(PL).

• 한국재료학회지
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• 제26권6호
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• pp.342-346
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• 2016

To observe the bonding structure and electrical characteristics of a GZO oxide semiconductor, GZO was deposited on ITO glasses and annealed at various temperatures. GZO was found to change from crystal to amorphous with increasing of the annealing temperatures; GZO annealed at $200^{\circ}C$ came to have an amorphous structure that depended on the decrement of the oxygen vacancies; increase the mobility due to the induction of diffusion currents occurred because of an increment of the depletion layer. The increasing of the annealing temperature caused a reduction of the carrier concentration and an increase of the bonding energy and the depletion layer; therefore, the large potential barrier increased the diffusion current dna the Hall mobility. However, annealing temperatures over $200^{\circ}C$ promoted crystallinity by the defects without oxygen vacancies, and then degraded the depletion layer, which became an Ohmic contact without a potential barrier. So the current increased because of the absence of a potential barrier.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.125-128
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• 2000

ZnO thin films on silicon substrates have been deposited by pulsed laser deposition technique(PLD). A Nd:YAG laser was used with the wavelength of 355 nm. In order to investigate the effect of oxygen post-annealing treatment on the property of ZnO thin films, deposited film has been annealed at the substrate temperature of $440^{\circ}C$. After post-annealing treatment in the oxygen ambient, the stoichiometry of ZnO film has been characterized be improved which results in higher UV emission intensity of photoluminescence.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.119-122
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• 2001

ZnO thin films on (001) sapphire substrates have been deposited by pulsed laser deposition(PLD) technique at the oxygen pressure of 350 mTorr. In order to investigate the effect of post-annealing treatment with oxygenn pressure of 350 mTorr on the optical property of ZnO thin films, films have been annealed at various substrate temperatures after deposition. After post-annealing treatment in the oxygen ambient, the optical properties of the ZnO thin films were characterized by PL(Photoluminescence) and structural properties of the ZnO were characterized by XRD, and have investigated structural property and optical property for application of light emission device.

• 반도체디스플레이기술학회지
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• 제7권3호
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• pp.51-54
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• 2008

In this study, we investigated variations in undoped ZnO thin film properties with working pressure, $O_2$/Ar ratio, and annealing ambient. Higher vacuum pressure during deposition was observed to bring about slower growth rate resulting in samples with better crystallinity as well as hole generation efficiency through formation of shallower oxygen interstitial. Given that $O_2$/Ar ratio is greater than unity, O provided from the ambient to ZnO during annealing was found to preferably situate at interstitial sites. When He was used for the second annealing, significant changes were not observed. On the other hand, O ambient caused increased density of oxygen interstitial, thereby making the film more intrinsic-like high resistivity ZnO.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.191-191
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• 2009

$Bi_4Ti_3O_{12}$ (BiT) thin films were well developed on the Pt/Ti/$SiO_2/Si$ substrate by a metal organic decomposition (MOD) method. Oxygen was effective on the crystallization of the BiT thin films during a rapid thermal annealing process. The electrical properties of the BiT films dependant on the oxygen partial pressure were investigated. No crystalline phase was observed for the BiT film annealed at $700^{\circ}C$ under oxygen free atmosphere. However, its crystallinity was significantly evolutionned with increasing oxygen partial pressure. In addition, its dielectric and piezoelectric properties were enhanced with increasing oxygen partial pressure to 10 torr. Especially, the BiT film, annealed at $700^{\circ}C$ and 10 torr oxygen pressure, showed good dielectric properties: dielectric constant of 51 and dielectric loss of 0.2 % at 100 kHz. Its leakage current and piezoelectric constant ($d_{33}$) was also considerably improved, being as 0.62 nA/$cm^2$ at 1 V and approximately 51 pm/V, respectively.