• 제목/요약/키워드: time annealing

검색결과 934건 처리시간 0.029초

방사선을 이용하여 제조한 poly(vinyl alcohol)/poly(acrylic acid) 하이드로젤의 제조 및 특성 (Preparation and Characterization of Poly(vinyl alcohol)/Poly(acrylic acid) Hydrogel by Radiation)

  • 박종석;김현아;최종배;권희정;임윤묵;노영창
    • 방사선산업학회지
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    • 제5권4호
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    • pp.377-382
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    • 2011
  • Poly(vinyl alcohol) (PVA) is an interesting material with good biocompatibility, high elasticity and hydrophilic chacrateristics. In this study, crosslinked hydrogels based on PVA, and poly(acrylic acid) (PAAc) were prepared by gamma-ray irradiation. PVA and PAAc powders were dissolved in deionized water, and then irradiated by a gamma-ray with a radiation dose of 50 kGy to make hydrogels. The hydrogels were then annealed in an oven at $120^{\circ}C$ for 10 min, 30 min and 50 min under nitrogen atmosphere. The properties of a hydrogel such as gel fraction, swelling behavior, thermogravimetric analysis (TGA) and adhesive strength as a function of PAAc content and annealing time were investigated. The gel fraction decreases with decreasing PAAc content and increasing annealing time. The thermal behaviors have shown different patterns according to the annealing time. The adhesive strength increases with increasing PAAc content.

BAF에서 분위기 가스와 대류판 형태가 열전달 특성에 미치는 영향 (Effects of the Convector Plate Shape and the Atmospheric Gas on Characteristics of Heat Transfer in a Batch Annealing Furnace)

  • 윤순현;김문경;김대성
    • 한국정밀공학회지
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    • 제13권8호
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    • pp.72-79
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    • 1996
  • In a BAF(Batch Annealing Furnace), various studies have been pursued in order to reduce energy consumption rate to improve productivity and to stabilize the properties of products. The purpose of this study was to investigate the effects of both the atmospheric gas and convector plate shapes on the augmentation of heat transfer. The use of hydrogen instead of nitrogen as an atmospheric gas, combined with high convection in the BAF, has shown that considerable increases in furnace out put and significantly improved material quality are attainable. Because convector plate shapes make the atmosheric gas easily flow density, high diffusivity and reducing character of hydrogen, a better heat transfer rates resulting in uniform material temperature distribution and improved coil surface quality can be achieved. Also, it was found that the closed convector plate took more time for the annealing cycle time than the other plate type(open-type)by about ten hours.

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(m, n)중 연속(r, s) : F 시스템의 정비모형에 대한 개미군집 최적화 해법 (Ant Colony Optimization Approach to the Utility Maintenance Model for Connected-(r, s)-out of-(m, n) : F System)

  • 이상헌;신동열
    • 산업공학
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    • 제21권3호
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    • pp.254-261
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    • 2008
  • Connected-(r,s)-out of-(m,n) : F system is an important topic in redundancy design of the complex system reliability and it's maintenance policy. Previous studies applied Monte Carlo simulation and genetic, simulated annealing algorithms to tackle the difficulty of maintenance policy problem. These algorithms suggested most suitable maintenance cycle to optimize maintenance pattern of connected-(r,s)-out of-(m,n) : F system. However, genetic algorithm is required long execution time relatively and simulated annealing has improved computational time but rather poor solutions. In this paper, we propose the ant colony optimization approach for connected-(r,s)-out of-(m,n) : F system that determines maintenance cycle and minimum unit cost. Computational results prove that ant colony optimization algorithm is superior to genetic algorithm, simulated annealing and tabu search in both execution time and quality of solution.

열처리 조건에 따른 폴리(에틸렌 테레프탈레이트)의 열적 특성 및 결정화 거동 (Thermal Properties and Crystallization Behaviors of Poly(ethylene terephthalate) at Various Annealing Conditions)

  • 류민영;배유리
    • 폴리머
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    • 제27권2호
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    • pp.113-119
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    • 2003
  • 폴리(에틸렌 테레프탈레이트) (PET)의 열처리 조건들 즉, 상대 습도, 온도 그리고 시간 등에 따라 나타나는 PET의 열적 특성과 결정화 거동에 대해서 연구하였다. PET샘플에 열처리를 수행한 후 수분 함유량, 유리 전이온도($T_g$), 그리고 결정화 온도($T_{\propto}$) 등의 변화를 조사하였다. 그리고 열처리된 PET시편에 대해서 결정화를 시키고 결정화도에 따른 열변형 온도(HDT)를 측정하였다. 또한 사출 성형으로 제작된 PET샘플의 열처리 후 잔류 응력의 완화를 편광 필름을 통하여 조사하였다. 열처리 시의 상대 습도, 온도, 그리고 시간이 증가함에 따라 PET샘플 내의 수분 함유량은 최대 6000 ppm이상 까지 증가하였다. $T_g$$T_c$는 시편 내에 수분 함유량이 증가할수록 감소하였다. PET샘플의 결정화도는 수분의 함유량이 증가함에 따라 증가되었다. 그러나 같은 양의 수분 함량에서 결정화도는 열처리의 조건에 따라 다르게 나타났다. PET샘플 내의 잔류응력의 완화는 열처리 조건에 따라 다르게 나타났으며, PET샘플 내에 잔류 응력이 감소할수록 최대 결정화도는 증가하였다.

전해증착 Cu(In,Ga)Se2 박막의 Se가스 분위기 열처리 (Annealing of Electrodeposited Cu(In,Ga)Se2 Thin Films Under Se Gas Atmosphere)

  • 신수정;김명한
    • 한국재료학회지
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    • 제21권8호
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    • pp.461-467
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    • 2011
  • Cu(In, Ga)$Se_2$ (CIGS) precursor films were electrodeposited on Mo/glass substrates in acidic solutions containing $Cu^{2+}$, $In^{3+}$, $Ga^{3+}$, and $Se^{4+}$ ions at -0.6 V (SCE) and pH. 1.8. In order to induce recrystallization, the electrodeposited $Cu_{1.00}In_{0.81}Ga_{0.09}Se_{2.08}$ (25.0 at.% Cu + 20.2 at.% In + 2.2 at.% Ga + 52.0 at.% Se) precursor films were annealed under a high Se gas atmosphere for 15, 30, 45, and 60 min, respectively, at $500^{\circ}C$. The Se amount in the film increased from 52 at.% to 62 at.%, whereas the In amount in the film decreased from 20.8 at.% to 9.1 at.% as the annealing time increased from 0 (asdeposited state) to 60 min. These results were attributed to the Se introduced from the furnace atmosphere and reacted with the In present in the precursor films, resulting in the formation of the volatile $In_2Se$. CIGS precursor grains with a cauliflower shape grew as larger grains with the $CuSe_2$ and/or $Cu_{2-x}Se$ faceted phases as the annealing times increased. These faceted phases resulted in rough surface morphologies of the CIGS films. Furthermore, the CIGS layers were not dense because the empty spaces between the grains were not removed via annealing. Uniform thicknesses of the $MoSe_2$ layers occurred at the 45 and 60 min annealing time. This implies that there was a stable reaction between the Mo back electrode and the Se diffused through the CIGS film. The results obtained in the present research were sufficiently different from comparable studies where the recrystallization annealing was performed under an atmosphere of Ar gas only or a low Se gas pressure.

Thermal Annealing 효과에 의한 다층 박막 FBAR 소자의 공진 특성 개선 (Improvement of Resonant Characteristics due to the Thermal Annealing Effect in Multi-layer Thin-film SMR Devices)

  • 김동현;임문혁;;윤기완
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2003년도 추계종합학술대회
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    • pp.633-636
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    • 2003
  • 본 논문에서는 ZnO를 사용한 다층 박막 SMR 소자의 공진 특성을 개선하기 위해서 실리콘 기판 상부에 형성된 W/SiO$_2$의 Bragg reflector를 thermal annealing한다. SMR 소자의 공진 특성은 Bragg reflector에 적응된 annealing 조건에 의존함을 관찰할 수 있었다. annealing을 하지 않은 Bragg reflector를 갖는 SMR 소자와 비교했을 경우, 40$0^{\circ}C$/30min의 조건으로 annealing된 Bragg reflector를 갖는 SMR 소자가 가장 훌륭한 공진특성을 나타내었다. 새롭게 제안된 annealing 공정은 W/SiO$_2$ 다층 박막 Bragg reflector를 갖는 SMR 소자의 공진 특성을 효과적으로 개선시키는데 있어 매우 유용할 것으로 보인다.

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Annealing Effects on Ultra thin MOS Capacitors

  • Ng, Alvin Chi-hai;Xu, Jun;Xu, J.B.;Cheung, W.Y.
    • E2M - 전기 전자와 첨단 소재
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    • 제16권9호
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    • pp.62.1-62
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    • 2003
  • Silicon oxide with thickness lee than 9 nm is fabricated by tube furnace oxidation. Nitrogen is added to dilute the oxidation rate. Aluminum dots with radius of 0.05 cm are deposited on the oixde. High frequency capacitance-voltage(HF C-V), conductance-voltage(G-V) and current-voltage(I-V) characteristics are measured. Annealing under nitrogen atmosphere is carried out with different time and at different temperature. Densities of the interface states before and after annealing are compared. After annealing, a decrease in density of the interface states is found. Experiments show that 45$0^{\circ}C$ annealing for 30 minutes has the lowest density of the interface states.

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Rescaled Simulated Annealing에 의한 항공우주 구조물의 최적설계 (Optimization of Aerospace Structures using Resealed Simulated Annealing)

  • 지상현;박정선
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.522-527
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    • 2004
  • Resealed Simulated Annealing (RSA) has been devised for improving the disadvantage of Simulated Annealing (SA) which require tremendous amount of computation time. RSA and SA have been for optimization of satellite structures and for comparison of results from two algorithms. As a practical application, a satellite structure is optimized by the two algorithms. Weights of satellite upper platform and propulsion module are minimized. MSC/NASTRAN is used for the static and dynamic analysis. The optimization results of the RSA are compared with results of the classical SA. The numbers of optimization iterations could be effectively reduced by the RSA.

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비정질 $As_{10}Ge_{15}Te_{75}$박막의 D.C. 스위칭 임계전압 특성 (The characteristics of D.C. switching threshold voltage for amorphous $As_{10}Ge_{15}Te_{75}$ thin film)

  • 이병석;이현용;이영종;정홍배
    • E2M - 전기 전자와 첨단 소재
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    • 제9권8호
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    • pp.813-818
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    • 1996
  • Amorphous As$_{10}$Ge$_{15}$ Te$_{75}$ device shows the memory switching characteristics under d.c. bias. In bulk material, a-As$_{10}$Ge$_{15}$ Te$_{75}$ switching threshold voltage (V$_{th}$) is very high (above 100 volts), but in the case of thin film, V$_{th}$ decreases to a few or ten a few volts. The characteristics of V$_{th}$ depends on the physical dimensions such as the thickness of thin film and the separation between d.c. electrodes, and the annealing conditions. The switching threshold voltage decreases exponentially with increasing annealing temperature and annealing time, but increases linearly with the thickness of thin film and exponentially with increasing the separation between d.c. electrodes. The desirable low switching threshold voltage, therefore, can be obtained by the stabilization through annealing and changing physical dimensions.imensions.sions.

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Si 기판 위에 형성된 InAs 양자점의 열처리에 의한 표면 상태의 변화 (Temperature-dependent Morphology of Self-assembled InAs Quantum Dots Grown on Si Substrates)

  • 유충현
    • 한국전기전자재료학회논문지
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    • 제20권10호
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    • pp.864-868
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    • 2007
  • Effect of high-temperature annealing on morphology of fully coherent self-assembled InAs quantum dots' grown on Si (100) substrates at $450^{\circ}C$ by atmospheric pressure metalorganic chemical vapor deposition(APMOCVD) was investigated by atomic force microscopy(AFM). When the dots were annealed at 500 - 600$^{\circ}C$ for 15 sec - 60 min, there was no appreciable change in the dot density but the heights of the dots increased along with the reduction in the diameters. In segregation from the InAs quantum dots and/or from the 2-dimensional InAs wetting layer which was not transformed into quantum dots looked responsible for this change in the dot size. However the change rates remained almost same regardless of annealing time and temperature, which may indicate that the morphological change due to thermal annealing is done instantly when the dots are exposed to high temperature annealing.