• 대한전기학회논문지
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• 제43권3호
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• pp.442-446
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• 1994

In this study, microwave dielectric properties of 0.182BaO-0.818TiOS12T ceramics were investigated with sintering temperature and annealing time, and the application for the microwave dielectric resonator was studied. In the specimen simtered at 1400[$^{\circ}C$], dielectric constant, unloaded Q and temperature coefficient of resonant frequency had good values of 35.36, 5692, -4.43[ppm/$^{\circ}C$], respectively. The specimen which temperature coefficient of resonant frequency($\tau$f) was vared positive to negative value was selected, thereafter microwave dielctric properties was investigated with annealing time(0~4[hr]) in the fixed annealing temperature of 1350[$^{\circ}C$]. Increasing the annealing time, dielectric constant and unloaded Q were increased and temperature coefficient of resonant frequency was decreased.

• Journal of Magnetics
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• 제10권4호
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• pp.133-136
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• 2005

The NiMn/NiFe bilayer structure which was short time annealed in order to induce unidirectional anisotropy were studied as a function of annealing temperature. The maximum exchange bias field of NiMn/NiFe bilayer was presented at $250^{\circ}C$ after short time annealing process with no external field. The appearance of exchange bias was due to phase transformation of NiMn layer. In plane angular dependence of a resonance field distribution which measured by FMR was analysed as a combined effect of unidirectional anisotropy and uniaxial anisotropy. The resonance field and the line width from FMR measurement were also analysed with annealing temperature.

• 대한기계학회논문집
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• 제18권5호
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• pp.1227-1234
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• 1994

A cold spot temperature control system for the batch annealing furnace has been established in order to reduce energy consumption which is essential to improve productivity and stabilize the properties of products. A relationship between annealing cycle time and gas flow rate is developed and also for the variation of coil cold spot temperature with time during heating, and actual temperature measurements at mid-width of each coil during soaking. The results of the temperature variation effect on the cold rolled steel sheet batch annealing are as follows. (1) Cooling rate increasing gradually with increasing atmospheric gas flow, but heating rate is hardly increasing without atmospheric gas component change. (2) In case of short time heating, the slowest heating part is the center of B coil and in case of ling time heating, the low temperature point moves from the center of coil to inside coil. (3) The outside of top coil is the highest temperature point under heating, which becomes the lowest temperature point under cooling. (4) Soaking time determination depends on the input coil width, and soaking time for quality homogenization of 1214 mm width coil must be 2 hours longer than that of 914 mm width coil.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.371-372
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• 2012

We have studied lead-based gapless semiconductors, $PbPdO_2$, which is very sensitive to external parameters such as temperature, pressure, electric field, etc[1]. We have fabricated pure $PbPdO_2$, Co- and Mn-doped $PbPdO_2$ thin films using the pulsed laser deposition. Because of the volatile element of Pb, it is very difficult to grow the films. Note that in case of $MgB_2$, Mg is also volatile element. So in order to enhance the quality of $MgB_2$, some experiments are carried out in annealing with Mg-rich atmosphere [2]. This annealing process with volatile element plays an important role in making smooth surface. Thus, we applied such process to our studies of $PbPdO_2$ thin films. As a result, we found the optimal condition of ex-situ annealing temperature ${\sim}650^{\circ}C$ and time ~12 hrs. The ex-situ annealing brought the extreme change of surface morphology of thin films. After ex-situ annealing with PbO-rich atmosphere, the grain size of thin film was almost 100 times enlarged for all the thin films and also the PbO impurity phase was smeared out. And from X-ray diffraction measurements, we determined highly crystallized phases after annealing. So, we measured electrical and magnetic properties. Because of reduced grain boundary, the resistivity of ex-situ annealed samples changed smaller than no ex-situ sample. And the carrier densities of thin films were decreased with ex-situ annealing time. In this case, oxygen vacancies were removed by ex-situ annealing. Furthermore, we will discuss the transport and magnetic properties in pure $PbPdO_2$, Co- and Mn-doped $PbPdO_2$ thin films in detail.

• 한국정보시스템학회지:정보시스템연구
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• 제28권4호
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• pp.175-197
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• 2019

Purpose This study develops a heuristic algorithm to solve the time-resource tradeoffs in project scheduling problems with a real basis. Design/methodology/approach Resource constrained project scheduling problem with time-resource tradeoff is well-known as one of the NP-hard problems. Previous researchers have proposed heuristic that minimize Makespan of project scheduling by deriving optimal combinations from finite combinations of time and resource. We studied to solve project scheduling problems by deriving optimal values from infinite combinations. Findings We developed heuristic algorithm named Push Algorithm that derives optimal combinations from infinite combinations of time and resources. Developed heuristic algorithm based on simulated annealing shows better improved results than genetic algorithm and further research suggestion was discussed as a project scheduling problem with multiple resources of real numbers.

• 한국전기전자재료학회논문지
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• 제13권12호
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• pp.1003-1010
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• 2000

Thin films of vanadium oxide(VOx) have been deposited by r.f. magnetron sputtering from V$_2$O$\_$5/ target in gas mixture of argon and oxygen. Crystal structure, surface morphology, chemical composition, molecular structure and optical properites of films in-situ annealed in O$_2$ambient with various heat-treatment conditions are characterized through XRD, SEM, AES, RBS, RTIR and optical absorption measurements. The films annealed below 200$\^{C}$ are amorphous, and those annealed above 300$\^{C}$ are polycrystalline. The growth of grains and the transition of vanadium oxide into the higher oxide have been observed with increasing the annealing temperature and time. The increase of O/V ratio with increasing the annealing temperature and time is attributed to the diffusion of oxygen and the partial filling of oxygen vacancies. It is observed that the oxygen atoms located on the V-O plane of V$_2$O$\_$5/ layer participate more readily in the oxidation process. Also indirect and direct optical band gaps were increased with increasing the annealing temperature and time.

• Progress in Superconductivity
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• 제1권1호
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• pp.9-13
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• 1999

The influence of quenching temperature and annealing time on superconducting characteristics has been investigated for a $(Pb_{0.6}V_{0.4})Sr_2(Ca_{0.65}Er_{0.35})Cu_2O_z$ compound. From the resistivity measurements for samples annealed at $400^{\circ}C$ to $860^{\circ}C$ in oxygen and subsequently quenched, it is observed that $T_c$(zero) of the sample decreases with the increase of annealing temperature up to $600^{\circ}C$ and increases again beyond $700^{\circ}C$. Annealings of the sample at $860^{\circ}C$ show that $T_c$(zero) goes through a maximum of 62K with the increase of the annealing time. It is also found that $T_c$(zero) of the sample quenched from high temperature decreases when the sample is subjected to low temperature annealing below. $600^{\circ}C$ in oxygen. The experimental results indicate that the as-prepared samples contain excessive oxygen and removal of this excessive oxygen in as-prepared samples is a key factor in controlling the superconducting properties of the samples and are discussed in connection with thermal gravimetric measurements.

• Transactions on Electrical and Electronic Materials
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• 제8권4호
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• pp.161-165
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• 2007

In this work, Ni thin films with different thickness from $1,523{\AA}\;to\;9,827{\AA}$ were deposited for the application of micro thermal flow sensors by a magnetron sputtering and oxidized through annealing at $450^{\circ}C$ with increasing annealing time. The initial variation of resistivity decreased radically with increasing films thickness, then gradually stabilizes as the thickness increases. The resistivity of Ni thin films with $3,075{\AA}$ increased suddenly with increasing annealing time at $450{\circ}C$, then gradually stabilizes as the thickness increases after the annealing time 9 h. In case of $3,075{\AA}\;and\;9,827{\AA}$ films, the average of TCR values, measured for the operating temperature range of $0^{\circ}C\;to\;180^{\circ}C$, were $2,413.1ppm/^{\circ}C\;and\;4,438.5ppm/^{\circ}C$, respectively. Because of their high resistivity and very linear TCR, Ni oxide thin films are superior to pure Ni and Pt thin films for flow and temperature sensor applications.

• 한국자기학회지
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• 제5권5호
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• pp.478-482
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• 1995

The iron-based Metglas 2605S3A amorphous alloy ribbons are annealed at $435^{\circ}C$ for various periods from 5 to 210 min, and the effect of annealing is investigated on the dc magnetic properties of the ribbon. Typical square-type hysteresis loops are observed for the ribbons annealed fo 5 min, indicative of the nearly complete removal of residual stresses which are produced during melt-quenching. As the annealing time increases, the coercivity increases and the shape of hysteresis loops transforms to round type and finally to sheared one at the longest annealing time of 210 min. These results may be explained by the formation of clusters with chemical shortorder and very fine crystallites (at the annealing time of 210 min), and the diffusion-induced stresses during the formation of the clusters. For the samples annealed for 5 min, very good dc properties of the squareness ratio, coercivity and maximum permeability are observed, but, rather unexpectedly, the initial permeability is found to be very low. These results are considered to be due to a simple domain structure consisting of very small number of $^{\circ}$ domains.

• 공업화학
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• 제10권1호
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• pp.35-40
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• 1999

Hard segment 함량이 35%와 53%로 서로 다른 두 개의 열가소성 폴리우레탄 시료 (각각 TPU-35와 TPU-35)와 이들을 70/30, 50/50, 30/70 wt%로 용융 블렌딩한 조성들이 annealing 온도와 시간에 따라 변화할 수 있는 유리전이온도와 용융피이크, 분자량 및 분자량 분포도의 변화를 관찰하였다. TPU의 $T_g$는 hard segment 함량이 많을수록 높은 값을 보였으며 annealing 온도와 시간에 따라 hard microdomain 구조의 미약한 관계에 의한 용융피이크의 크기와 온도 등이 변하였다. 이는 annealing에 의한 열이 long-range 혹은 short-range segmental motion의 거동, 비결정 microphase 구조의 order-disorder 전이, domain의 크기 및 결정구조의 질서도 등 여러 가지 복합적인 영향을 끼친 결과로 사료된다. 미세 결정의 용융 결과로 나타나는 $T_3$단일 피이크만이 존재하는 annealing 온도는 TPU-35, TPU-44와 TPU-53에 대해 각각 130, 170 및 $180^{\circ}C$이었다. Annealing 온도와 시간에 따른 분자량 및 분자량 분포도 변화 측정에서 TPU-35는 $135^{\circ}C$에서, TPU-44(TPU-35/TPU-53=50/50 블랜드)는 $170^{\circ}C$, 그리고 TPU-53은 $180^{\circ}C$에서 수평균 및 중량평균 분자량의 증가와 더불어 polydispersity(PI)는 감소를 보였다. 이 변화는 같은 조건의 annealing 온도에 따른 용융피이크 변화에서 $T_3$단일 피이크만 남게 되는 annealing온도와 일관성을 보이고 있는데, 이는 이들 시료가 특정한 annealing 온도에서 chain dissociation과 recombination이 동시에 일어나므로써 빚어진 결과로 추측된다.