• Journal of the Korean Magnetics Society
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• v.8 no.6
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• pp.335-340
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• 1998

Colossal magnetoresistance $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ material has been produced by a metal-salt routed sol-gel process method. Magnetic properties of $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ have been studied with x-ray diffraction, Rutherford back-scattering spectroscopy(RBS), vibrating sample magnetometer, and Mossbauer spectroscopy. Crystalline $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ was perovskite cubic structure with a lattice parameter $a_0=3.868$\AA$$. And there was no appreciable change in the value of the lattice parameter when a small amount (x=0.01) of iron was added. However, Mossbauer and VSM data indicate the Curie temperature of the $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ decreased from 282 to 270 k and also the saturation magnetization from 84 to 81 emu/g at 77 K. Mossbauer spectra of $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ have been taken at various temperatures ranging form 4.2 K to room temperature. Analysis of $^{57}Fe$ Mossbauer data in terms of the local configurations of Mn atoms has permitted the influence of the magnetic hyperfine interactions to be monitored. The isomer shifts show that the charge state of all Fe ions are ferric. The magnetoresistance of $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ was about 33 % at semiconductor-metal transition temperature $T_{SC-M}=250K$.

• Journal of the Korean Magnetics Society
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• v.9 no.3
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• pp.136-142
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• 1999

$Ni_{0.65}Zn_{0.35}Cu_{0.3}Fe_{1.7}O_4$ has been studied with x-ray diffraction, Mossbauer spectroscopy, and vibrating sample magnetometer. The crystal structure is found to be a cubic spinel with the lattice constant $a_0=8.403{\AA}$. Mossbauer spectra of have been taken at various temperatures ranging from 12 K to 665 K. as the temperature increases toward $T_N$ a systematic line broadening effect in the Mossbauer spectrum is observed and interpreted to originate from different temperature dependencies of the magenetic hyperfine fields at various iron sites. Also, by using binomial distribution equation we obtained the hyperfine fields of tetrahedral[A] and octahedral sites[B], $H_{hf}(A)=470\;kOe,\; H_{hf}(B0)=495 \;kOe,\; H_{hf}(B1)=485\;kOe, \;H_{hf}(B2)=453\;kOe,\; H_{hf}(B3)=424\;kOe,\; H_{hf}(B4)=390\;kOe,\; H_{hf}(Bavr)=451\;kOe$ respectively at room temperature. The isomer shift indicates that the iron ions are ferric at tetrahedral[A] and octahedral sites[B], respectively. The Neel temperature is determined to be $T_N=665\;K$. The results of the VSM data gave the magnetic moment and coercivity values of $M_S=66\; emu/g\;and\;H_C=36\;Oe$.

• Korean Journal of Optics and Photonics
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• v.13 no.5
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• pp.455-459
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• 2002

The transport and optical properties of $In_2O_3$:Zn(IZO) thin films grown by DC magnetron sputtering deposition have been studied. The deposition temperatures ($T_s$) were varied from room temperature to $400^{\circ}C$ in $50^{\circ}C$ steps. The IZO films are an amorphous phase for $T_s$<$300^{\circ}C$ and polycrystalline phase for $350^{\circ}C$＜$T_s$. In contrast to ordinary films, amorphous IZO films have lower resistivity and higher optical transmittance than polycrystalline IZO films. The resistivity of amorphous IZO was in the range of 0.29~0.4 m$\Omega$cm and that of polycrystalline IZO was in the range of 1~4 m$\Omega$cm. The carrier type for IZO film was found to be n-type, and the carrier density, was $3~5{\times}10^{20}/cm^3$. The Hall mobility, $({\mu}_H)$, was 20~$50\textrm{cm}^2$/V.sec. The predominant scattering mechanisms in both amorphous and polycrystalline IZO films were believed to be ionized impurity scattering and lattice scattering. The visible transmittance of the IZO films, which decreases with an increase of TS, was above 80%.

• Food Engineering Progress
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• v.15 no.3
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• pp.230-234
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• 2011

The objective of this study was to optimize the thermal condition and determine the shelf life of heated Chunbokjang product. The optimum thermal condition of heated Chunbok-jang product was determined by sensory test, and heat penetration curve was obtained by Thermal Microprocessor. Sterilization time was a 21~23 min until $F_0$ value reached 9 min, depending upon the number of abalone. As solid content was reduced and temperature of sterilization was increased, the thermal death time was decreased. The score of sensory test indicated that there was no significant difference in flavor of heated Chunbok-jang product made at different sterilization temperatures (110, 121.1, 125, and $130^{\circ}C$). Heated Chunbok-jang product, however, sterilized at $125^{\circ}C$ showed the highest score in texture and taste values. Salinity and pH were not changed during seven month storages, but texture became firmer, and any microorganism had not been detected from the heated chunbok-jang product during these periods. As a result of storage experiment, the shelf-life of heated Chunbok-jang product was 3-month at room temperature.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.696-702
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• 2018

Recently, the current thermal battery technology needs new materials for electrodes in the power and energy density to meet various space and defense requirements. In this paper, to replace the pellet type Li(Si) anode having limitations of the formability and capacity, electrochemical properties of the lithium anode with high density for thermal batteries were investigated. The lithium anode (Li 17, 15, 13 wt%) was fabricated by mixing the molten lithium and iron powder used as a binder to hold the molten lithium at $500^{\circ}C$. The single cell with 13 wt% lithium showed a stable performance. The 2.06 V (OCV) of the lithium anode was significantly improved compared to 1.93 V (OCV) of the Li(Si) anode. Specific capacities during the first phase of the lithium anode and Li(Si) were 1,632 and $1,181As{\cdot}g^{-1}$, respectively. As a result of the thermal battery performance test at both room and high temperatures, the voltage and operating time of lithium anode thermal batteries were superior to those of using Li(Si) anode thermal batteries. The power and energy densities of Li anode thermal batteries were also remarkably improved.

• Korean Journal of Food Science and Technology
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• v.51 no.1
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• pp.29-34
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• 2019

In this study, a commercial production stepwise method for restorative rice with high quality and microbial safety was developed. The stepwise treatment method included steaming, refrigerated aging, and low temperature drying. The soaking rice was steamed twice at $90-100^{\circ}C$, and then, the rice was aged at $0-10^{\circ}C$, frozen at $-20^{\circ}C$, and dried at low temperatures with 5 m/s wind speed at $1-20^{\circ}C$ and 85% relative humidity. Applying the three steps improved sensory qualities compared with the conventional hot air drying and made storage at room temperature for 3 months possible. Specifically, the moisture content of the restorative rice was increased to 30%, which was 4.3 times higher than the 7% of the conventional air dried rice, and the rice grain shape was well maintained. The texture and appearance of the three-step rice were significantly improved (p<0.05) in a sensory evaluation.

• Journal of Mushroom
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• v.17 no.1
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• pp.7-11
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• 2019

We assessed the growth characteristics of Auricularia polytricha 'Geoni' cultivated in a simple greenhouse constructed of polyethylene (PE) without air conditioning (high temperature) and in an air conditioned mushroomhouse. The successful cultivation of A. polytricha 'Geoni' at high temperatures can reduce energy and facility investment costs. The comparison of growth characteristics of the fungi grown under the different temperature conditions revealed that fruit bodies were larger in the higher temperature condition, but were brighter in the lower temperature condition. Additionally, fruit body physiology was found to be not affected by temperature. In the PE greenhouse, the fresh weight of fruit body was higher in mid-June and early July. Therefore, it was possible to effectively control the growth period of the mushrooms during a high-temperature period. The findings indicate the potential to cultivate A. polytricha 'Geoni' in a simple PE greenhouse that is not cooled in summer, thus reducing energy costs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.503-509
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• 2019

The demand for smaller, faster, and multi-functional mobile devices in increasing at a rapidly increasing rate. In response to these trends, Stacked Chip Scale Package (SCSP) is used widely in the assembly industry. A film type adhesive called die attach film (DAF) is used widely for bonding chips in SCSP. The DAF requires high flowability at high die attachment temperatures for bonding chips on organic substrates, where the DAF needs to feel the gap depth, or for bonding the same sized dies, where the DAF needs to penetrate bonding wires. In this study, the mixture design of experiment (DOE) was performed for three raw materials to obtain the optimized DAF recipe for low elastic modulus at high temperature. Three components are acrylic polymer (SG-P3) and two solid epoxy resins (YD011 and YDCN500-1P) with different softening points. According to the DOE results, the elastic modulus at high temperature was influenced greatly by SG-P3. The elastic modulus at $100^{\circ}C$ decreased from 1.0 MPa to 0.2 MPa as the amount of SG-P3 was decreased by 20%. In contrast, the elastic modulus at room temperature was dominated by YD011, an epoxy with a higher softening point. The optimized DAF recipe showed approximately 98.4% pickup performance when a UV dicing tape was used. A DAF crack that occurred in curing was effectively suppressed through optimization of the cure accelerator amount and two-step cure schedule. The imizadole type accelerator showed better performance than the amine type accelerator.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.5
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• pp.328-334
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• 2022

The process that one may consciously focuses on necessary stimulation among tremendous amount of stimulation through human sensory systems is called attention in psychology. It is known that the attention can be affected by many factors such as room temperatures, humidity level, etc. In the field of sports science, ice packs are widely used for recovery from exercise fatigue providing fast heat transfer by conduction. However, the effect on attention by so-called iced-pack-cooling has not been tested. This research focuses on the attention levels when one is provided with a special cooling pad on their dorsal and lateral cervices. 40 subjects were divided into four groups and their attention level was evaluated based on the exposure conditions of combinations in reading and light walking with and without the cooling pad. The Frankfruter Aufmerksamkeits-Inventar, FAIR was used to evaluate the attention levels; the performance index, quality index, and continuity index consist of the FAIR test indicating the selectiveness of the attention, correctness of the attention, and maintaining term of the attention, respectively. Analysis of variance was carried out for those variables and post-hoc if applicable. When visual attention is constantly used for reading and studying, application of conductive heat transfer by the cooling pads is significantly helpful for improvement in selectiveness of the attention and maintaining terms of the attention levels. Also, light walking yielded improvement in selectiveness of the attention and maintaining terms of the attention levels; however one should presupposedly consider the loss of reading time.

• Journal of Conservation Science
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• v.37 no.6
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• pp.821-830
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• 2021

The weapons excavated from the de-militarized zones (DMZ) of Korea are vulnerable to corrosion due to the immediate and drastic environmental change. Especially, the chloride ions (Cl^-) in iron weapons cause active corrosion and require removal. In this study, conservation treatment and de-salination was performed for the discovered weapons from excavation sites of soldiers killed in action during the Korean War. Furthermore, an attempt was made to prepare the most stable plan for conservation treatment through the comparative study of soaking weapons in distilled water without chemicals and in a solution of sodium (SSC) at different temperatures. In the preliminarily experiments, the comparison of the eluted Cl^- ions according to different conditions of de-salination showed that the highest number of ions were detected from the de-salination with SSC at a temperature of 100℃, and its duration was much smaller, i.e., 1~2 weeks. Accordingly, for the parts from the guns and rifles amongst other objects, a six-time de-salination was conducted in the SSC solution for 8 hours at 100℃ and subsequently, for 16 hours at room temperature during which the distilled water and SSC were exchanged every week. However, in the case of a loaded rifle, the de-salination was not conducted, considering the risk that the high temperature and pressure by impregnation in vacuum could cause an explosion