• Journal of Magnetics
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• 제10권2호
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• pp.52-57
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• 2005

In this research, magnetoresistance (MR) ratio (MR), resistivity, and exchange coupling field $(H_{ex})$ behaviors for sputter deposited spin valves with FeMn antiferromagnetic layer have been extensively investigated by rapid thermal annealing (RTA) as well as conventional annealing (CA) method. 10 s of RTA revealed that interdiffusion was not significant up to $325^{\circ}C$ at the interfaces between the layers when the RTA time was short. The MR of FeMn spin valves were reduced when the spin valves were exposed to temperature of $250^{\circ}C$, even for a short time period of 10 s prior to CA. $H_{ex}$ was maintained up to $325^{\circ}C$ of CA when the specimen was subjected to 10 s of RTA at $200^{\circ}C$ prior to CA, which is $25^{\circ}C$ higher than the result obtained from the CA without prior RTA. Therefore, the stability of $H_{ex}$ could be enhanced by a prior RTA before performing CA up to annealing temperature of $325^{\circ}C$. MR and sensitivity of the specimens annealed without magnetic field up to $275^{\circ}C$ were recovered to the values prior to CA, but $H_{ex}$ was not recovered. This means that reduced MR sensitivity and MR during the device fabrication can be recovered by a field RTA.

• 한국자기학회지
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• 제12권4호
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• pp.132-136
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• 2002

유리기관 위에 이온 빔 증착(ion beam deposition ; IBD)법으로 제작한 버퍼층(buffer layer) Si의 두께에 따른 ［NiFe/FeMn/NiFe］3층박막의 결정성과 교환결합세기(exchange bias field ; H$_{ex}$)를 조사하였다. 버퍼층 Si는 NiFe층을 fcc(111)로 매우 우세하게 초기에 결정성장 시켰다. Si/NiFe 위의 증착된 FeMn층은 ${\gamma}$-fcc(111)구조로 성장함에 따라 안정되고 큰 H$_{ex}$를 가졌고, 버퍼 110 Oe로 거의 일정하였으며, 상부 FeMn/NiFe 이중구조의 H$_{ex}$는 300 Oe까지 증가하였다. 버퍼층이 Ta일 경우와 비교해서 Si일 때 H$_{ex}$와 결정성이 향상되었다.이 향상되었다.

• 한국자기학회지
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• 제13권4호
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• pp.176-181
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• 2003

금속마스크에 의해 패턴된 교환결합 이중박막 NiO(10∼60 nm)/NiFe(10 nm)의 모서리에서 발생한 여러 종류의 자구벽(magnetic domain wall)을 MFM(magnetic_ force microscopy)로 측정하였다. 박막의 모서리 경계선이 교환결합이방성 방향과 같은 방향일 때는 직선모양의 Neel 자구벽이 측정되었으며, 경계면이 이방성방향과 수직인 경우에는 zigzag Bloch 자구벽이 발견되었다. 이러한 자구벽은 NiO(60 nm)인 경우에는 교환결합세기(H$_{ex}$ = 75 Oe)가 박막경계면에서 발생한 반자장(demagnetization field) 세기보다 크기 때문에 발생하지 않았고, 교환결합세기가 약한 NiO(30 nm, H$_{ex}$ = 21 Oe)를 갖는 이중박막에서는 발견되었다. 이들 자구벽이 외부 자기장의 변화에 따라 움직이는 자화반전과정을 측정하기위해 $\pm$300 Oe까지 자기장을 가하면서 MFM을 측정하였다.

• 한국수소및신에너지학회논문집
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• 제35권2호
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• pp.140-145
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• 2024

High temperature co-electrolysis of H₂O-CO₂ mixtures using solid oxide cells has attracted attention as promising CO₂ utilization technology for production of syngas (H₂/CO), feedstock for E-fuel synthesis. For direct supply to E-fuel production such as hydrocarbon and methanol, the outlet gas ratio (H₂/CO/CO₂) of co-electrolysis should be controlled. In this work, current voltage characteristic test and product gas analysis were carried out under various reaction conditions which could attain proper syngas ratio.

• 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.

• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1752-1757
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• 2017

The aim of this study is to evaluate the radioactivity levels and radiological impacts of representative black sand samples collected from different locations in the Rashid area, Egypt. These samples were prepared and then analyzed using the high-resolution gamma ray spectroscopy technique with a high-purity germanium detector. The activity concentration ($A_c$), minimum detectable activity, absorbed gamma dose rate, external hazard index ($H_{ex}$), annual effective dose rate equivalent, radium equivalent, as well as external and internal hazard index ($H_{ex}$ and $H_{in}$, respectively) were estimated based on the measured radionuclide concentration of the $^{238}U$($^{226}Ra$) and $^{232}Th$ decay chains and $^{40}K$. The activity concentrations of the $^{238}U$, $^{232}Th$ decay series and $^{40}K$ of these samples varied from $45.11{\pm}3.1Bq/kg$ to $252.38{\pm}34.3Bq/kg$, from $64.65{\pm}6.1Bq/kg$ to $579.84{\pm}53.1Bq/kg$, and from $403.36{\pm}20.8Bq/kg$ to $527.47{\pm}23.1Bq/kg$, respectively. The activity concentration of $^{232}Th$ in Sample 1 has the highest value compared to the other samples; this value is also higher than the worldwide mean range as reported by UNSCEAR 2000. The total absorbed gamma dose rate and the annual effective dose for these samples were found to vary from 81.19 nGy/h to 497.81 nGy/h and from $99.86{\mu}Sv/y$ to $612.31{\mu}Sv/y$, which are higher than the world average values of 59 nGy/h and $70{\mu}Sv/y$, respectively. The $H_{ex}$ values were also calculated to be 3.02, 0.47, 0.63, 0.87, 0.87, 0.51 and 0.91. It was found that the calculated value of $H_{ex}$ for Sample 1 is significantly higher than the international acceptable limit of <1. The results are tabulated, depicted, and discussed within national and international frameworks, levels, and approaches.

• 운동영양학회지
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• 제23권3호
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• pp.1-12
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• 2019

[Purpose] The purpose of this study was to determine whether different types of carbohydrate diets with or without exercise changes energy metabolism at rest and during exercise. [Methods] To minimize differences in food and energy intake between experimental groups, mice were pairfed. After 1 week of adaptation, 40 male ICR mice (6 weeks old) were randomly divided into four groups: Sta. (high fat + high starch), Scu. (high fat + high sucrose), StaEX. (high fat + high starch + exercise), and SucEX. (high fat + high sucrose + exercise). StaEX. and ScuEX. groups underwent training by running on a treadmill five times a week. After 10 weeks of training, energy metabolism was measured for 24 h and during a 1 h exercise period. [Results] The final body weight showed no significant difference between the groups. However, the weight of abdominal tissues (epididymal, perirenal, and mesenteric adipose tissue) in training groups was markedly decreased following 10 weeks of training. Results of all energy metabolism (24 h at rest and during 1 h of exercise) showed no significant interactions between diet and exercise. A brief summary of the results of the energy metabolism is that the metabolism related indicators over 24 h were more affected by the dietary pattern than the exercise but during the 1 h of exercise, training had more effect on energy metabolism than diet. [Conclusion] Our findings confirm that: (a) the type of carbohydrates included in the diet influence the metabolic responses over 24 h, (b) training had more effect on energy metabolism than diet during 1 h of exercise, (c) both results; abdominal adipose tissue weight and fat oxidation during exercise are suggestive for a beneficial effect of moderate physical activity on weight maintenance.

• Plant Resources
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• 제3권3호
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• pp.179-183
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• 2000

The present study was carried out to clarify the chromosome numbers and karyotype of Atractylodes japonica Koidz. ex Kitam. and A. macrocephala Koidz.. The somatic chromosome numbers of two species were same; basic chromosome number x=12, and somatic chromosome numbers 2n=24. The present result of A. japonica Koidz. ex Kitam. was same to previously reports and that of A. macrocephala Koidz. was reported first in this study. Size and shape of chromosome were some different from A. japonica Koidz. ex Kitam. and A. macrocephala Koidz.. The karyotype of A. japonica Koidz. ex Kitam. was described as follows; 2n : 24 : 8L + 14M +2S : 2 $A^{sm}$ +2 $B^{m}$ +2 $C^{m}$ +2 $D^{st}$ + 2 $E^{m}$ +2 $F^{m}$ +2 $G^{m}$ +2 $H^{sm}$ + 2 $I^{m}$ + 2 $J^{m}$ + 2 $K^{m}$ + 2 $L^{m}$ . And the karyotype of A. macrocephata Koidz. was described as follows; 2n : 24 : 10L +12M +25 : 2 $A^{m}$ +2 $B^{sm}$ +2 $C^{sm}$ +2 $D^{sm}$ +2 $E^{sm}$ +2 $E^{sm}$ +2 $G^{sm}$ +2 $H^{m}$ +2 $I^{m}$ 2 $J^{m}$ +2 $K^{m}$ +2 $L^{m}$ . .

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2005년도 동계학술연구발표회 및 2차 아시안포럼
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• pp.80-81
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• 2005

The resilience of the exchange bias ($H_{EX}$) in ferromagnet / antiferromagnet bilayers is generally studied in terms of repeated hysteresis loop cycling or by protracted annealing under reversed field (training and long-term relaxation respectively). The stability of $H_{EX}$ is fundamental for practical application of exchange bias systems. In this paper we report measurements of training and relaxation in FeNi films coupled with the antiferromagnet FeMn. We show that $H_{EX}$ suppressed both by training and relaxation was partially recovered as soon as a field cycling for consecutive hysteresis loop measurement was stopped or the magnetization of the ferromagnet was switched back to the biased direction.

• 한국결정성장학회지
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• 제10권1호
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• pp.36-41
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• 2000

본 실험에서는 D.C magnetron sputtering을 사용하여 Ni-Fe/Co-Fe/Mn-Ir/Cu/buffer/Si 다층박막의 교환이방성에 관하여 연구하였다. 일반적인 Ni-Fe/Mn-Ir/buffer(Cu)/Si의 다층박막 구조는 낮은 교환결합 자계에 의하여 강자성체를 완전히 고착시키지 못한다. 따라서 Ni-Fe/Mn-Ir/buffer/Si 다층박막의 $H_{ex}$를 증가시키기 위해 하지층으로 Cu/Ta을 사용하여 Mn-Ir막의 결정립 부피를 증가시키고 Ni-Fe.Mn-Ir계면에 Co-Fe을 삽입하여 반강자성체/강자성체 계면에서의 epitaxy 경향을 향상시켜 2배 이상의 $H_{ex}$의 증가를 얻을 수 있었다. 또한 ferromagnete/Mn-Ir/buffer/Si의 다층박막 구조에서는 Mn-Ir거 두께에 따른 He일 변화 거동은 Mn-Ir/ferromagnete/buffer/Si다층박막구조와는 다른데 이와 같은 이유는 적층순서에 따라서 반강자성체 결정립의 부피분포와 계면에서의 교환결합 에너지가 차이가 나기 때문인 것으로 사료된다.