• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.10
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• pp.859-864
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• 2000

Recently IR detecting devices using MEMS have been actively studied. Microbolometer, one of these devices, detects the change of resistivity as the change of temperature of the device by absorbing IR, IR absorbing materials for microbolometer should have high TCR value and low noise characteristics which depends on resistivity. We fabricated multi-layer VOx thin films to improve the IR detectivity of uncooled IR devices and analyzed IR absorbing characteristics. We fabricated multi-layer VOx thin films by RF reactive sputtering method on SiNx substrate and changed characteristics using the different thickness of V and V$_2$O$\_$5/ thin films. Then we annealed them under 300$\^{C}$. The TCR (Temperature Coefficient of Resistance) measurement was carried out to estimate the IR detectivity of multi-layer VOx thin films. XRD (X-Ray Diffraction) analysis was carried out to estimate the IR detectivity of multi-layer VOx thin films. ZXRD (X-Ray Diffraction) analysis was used to find out phases and structures of V and V$_2$O$\_$5/ thin films. AES (Auger Electron Spectroscopy) analysis was used to find out composition of multi-layer VOx thin films before and after annealing. We obtained the optimum thickness range of V and V$_2$O$\_$5/ thin films from the result of AES analysis. We changed the thickness of V$_2$O$\_$5/ about 20 to 150 $\AA$ and thickness of V about 10 to 20 $\AA$. As the result of this, TCR value of multi-layer VOx thin films was about -2%/k and the resistivity was ∼1Ωcm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.6
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• pp.524-530
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• 2006

$xCa(Li_{1/4}Nb_{3/4})O_{3}-(1-x)CaTiO_{3}$ ceramics were sintered under the presence of zinc-borosilicate(ZBS) glass and resultant microwave dielectric properties were investigated with a view to applying the composition to low-temperature co-fired ceramic(LTCC) technology. The addition of $5{\sim}15wt%$ ZBS glass ensured successful sintering below $900\;^{\circ}C$. In general, increased addition of ZBS glass increased sinterability but it decreased the quality factor($Q{\times}f_{0}$) significantly due to the formation of an excessive liquid and second phases. As for the addition of $CaTiO_3$, the dielectric constant(${\epsilon}_r$) and temperature coefficient of resonant frequency(${\tau}_f$) increased, while the quality factor($Q{\times}f_{0}$) did not show an apparent change. The sintered $0.9Ca(Li_{1/4}Nb_{3/4})O_{3}-0.1CaTiO_{3}$ specimen at $900\;^{\circ}C$ with 10 wt% ZBS glass demonstrated 39.6 in dielectric constant(${\epsilon}_r$), 4,400 in quality factor$(Q{\times}f_{0}),\;and\;-11ppm/^{\circ}C$ in temperature coefficient of resonant frequency(${\tau}_f$).

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.373-388
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• 2016

Background: Recent inquiries into high-quality foods have discussed the importance of the functional aspects of foods, in addition to traditional quality indicators such as color, firmness, weight, trimming loss, respiration rate, texture, and soluble solid content. Recently, functional Chinese cabbage, which makes up a large portion of the vegetables consumed in Korea, has been identified as an anticancer treatment. However, the investigation of practical issues, such as the effects of storage conditions on quality indicators (including functional compounds), is still limited. Purpose: We reviewed various studies on variations in the quality indicators and functional compounds of Chinese cabbage in response to different storage environments, focusing on storage temperature and storage period. In particular, we emphasized the effect of storage temperature and storage period on glucosinolate (GSL) levels, in order to provide guidelines for optimizing storage environments to maximize GSLs. Additionally, we used response surface methodology to propose experimental designs for future studies exploring the optimal storage conditions for enhancing GSL contents. Review: Large variations in quality indicators were observed depending on the cultivar, the type of storage, the storage conditions, and the harvest time. In particular, GSL content varied with storage conditions, indicating that either low temperatures or adequate air composition by controlled atmospheric storage may preserve GSL levels, as well as prolonging shelf life. Even though genetic and biochemical approaches are preferred for developing functional Chinese cabbage, it is important to establish a practical method for preserving quality for marketability; a prospective study into optimal storage conditions for preserving functional compounds (which can be applied in farms), is required. This may be achievable with the comprehensive meta-analysis of currently published data introduced in this review, or by conducting newly designed experiments investigating the relationship between storage conditions and the levels of functional compounds.

• Applied Science and Convergence Technology
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• v.26 no.4
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• pp.70-73
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• 2017

The dielectric constant and loss of poling/non-poling was measured in the $Pb_{1-3x/2}La_x[(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ samples. The addition of $La^{3+}$ to the $Pb_{1-3x/2}La_x[(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ did not cause a large change in grain size. But the addition of $La^{3+}$ did show transition temperature, which shifted toward low temperature in the $Pb[(Mg_{1/3}Ta_{2/3})Zr]O_3$ systems. In addition, the dielectric and pyroelectric properties (${\varepsilon}{\sim}20000$, $p{\sim}0.03C/m^2K$) of this system using $La^{3+}$ have been greatly improved. Pyroelectrics $Pb_{0.97}La_{0.02}(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ system was found to have a relatively high ferroelectric FOMs ($F_V{\sim}0.035m^2/C$, $F_D{\sim}0.52{\times}10^{-4}Pa^{-1/2}$) at room temperature. Spontaneous polarization showed a value of $0.27{\sim}0.35C/m^2$ in the composition added to $La^{3+}$. The piezoelectric constant ($d_{33}=350{\sim}490pC/N$) and electromechanical coupling factor ($k_P=0.25{\sim}0.35$) are obtained in $Pb_{1-3x/2}La_x[(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ compositions with $La^{3+}$ dopant.

• Journal of Powder Materials
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• v.26 no.5
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• pp.405-409
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• 2019

Piezoelectric ceramic specimens with the $Pb(Mg_{1/3}Nb_{2/3})_{0.65}Ti_{0.35}O_3$ (PMN-PT) composition are prepared by the solid state reaction method known as the "columbite precursor" method. Moreover, the effects of the $Li_2O-Bi_2O_3$ additive on the microstructure, crystal structure, and piezoelectric properties of sintered PMN-PT ceramic samples are investigated. The addition of $Li_2O-Bi_2O_3$ lowers the sintering temperature from $1,200^{\circ}C$ to $950^{\circ}C$. Moreover, with the addition of >5 wt.% additive, the crystal structure changes from tetragonal to rhombohedral. Notably, the sample with 3 wt.% additive exhibits excellent piezoelectric properties ($d_{33}=596pC/N$ and Kp = 57%) and a sintered density of $7.92g/cm^3$ after sintering at $950^{\circ}C$. In addition, the sample exhibits a curie temperature of $138.6^{\circ}C$ at 1 kHz. Finally, the compatibility of the sample with a Cu electrode is examined, because the energy-dispersive X-ray spectroscopy data indicate the absence of interdiffusion between Cu and the ceramic material.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.11
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• pp.1616-1623
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• 2008

This study was conducted to determine the effect of hot environment and dietary crude protein level (CP) on performance, carcass characteristics, meat visual quality, muscle chemical composition and malondialdehyde (MDA) concentration of tissues in broilers. Two hundred and sixteen 21-d old Arbor Acre broilers were used in a $4\times3$ factorial arrangement and randomly reared in 4 environmental chambers and fed on 3 diets with different CP levels for 3 weeks. The results showed: (1) when air temperature (AT) rose to $33^{\circ}C$, average daily feed intake, average daily gain, carcass weight, right breast meat weight, left thigh and drumstick meat weight decreased (p<0.05) and feed conversion rate decreased (p<0.05), but the ratio of carcass to live weight and of left thigh and drumstick meat weight to carcass weight increased (p<0.05). (2) There were significant differences in pH and shear force in breast meat, and shear force, L* and a* in thigh meat (p<0.01 or 0.05) among hot environments. Dietary CP level tended to affect breast meat pH and pH and L* of thigh meat (p<0.06 or 0.09). Compared to the normal temperature ($22^{\circ}C$), low temperature ($15^{\circ}C$) and hot humid (AT $33^{\circ}C$, relative humidity (RH) 80%) treatments significantly (p<0.05) decreased the tenderness of thigh meat. L* and a* value in thigh meat under high temperature treatments, regardless of RH, were higher (p<0.05) than those under normal temperature. (3) Protein content in breast and thigh meat of broilers fed under high temperature ($33^{\circ}C$) was lower (p<0.05) than that under $22^{\circ}C$, but fat content had an adverse change. High temperature ($33^{\circ}C$) increased the moisture of breast meat significantly (p<0.05). Protein content in breast meat increased significantly (p<0.05), in which fat content had an adverse change (p<0.05), when the dietary protein rose. (4) MDA concentration in liver and breast meat under hot humid (AT $33^{\circ}C$, RH 80%) treatment increased markedly (p<0.05). (5) High humidity could sharpen the bad effect of high temperature on performance, carcass yield and choice cuts, crude protein and moisture content in breast meat. It was concluded that a hot environment could affect the performance and meat quality of broiler chicks more significantly than CP level and that high humidity would aggravate the bad influence of high temperature on the broiler.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.3
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• pp.155-166
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• 2007

We carried out a study on the marine environment, such as water temperature, salinity, density and chlorophyll ${\alpha}$, and the distribution of phytoplankton community, such as species composition, dominant species and standing crops in the Southwestern Sea of Korea during early summer 2005. According to the analysis of a T-S diagram, three characteristics of water masses were identified. We classified them into Korean and Chinese coastal water, the cold water and the oceanic water. The first was characterized by high temperature and low salinity in the surface layer influenced by river run offs from China and Korea, the second by low temperature and salinity in bottom layer originated from the bottom cold water of the Yellow Sea, and the third by high temperature and high salinity influenced by Tsushima warm currents. The internal discontinuous layer among them was formed at the intermediate depth (about $10{\sim}20\;m$ layer). And the thermal front appeared in the central parts between Tsushima warm currents and Korean and Chinese coastal waters in the Southwestern Sea of Korea. Chlorophyll ${\alpha}$ concentration was high values in the Korean coastal waters and sub-surface layers. But It was low concentration in the Tsushima warm currents regions. The $Chl-{\alpha}$ maximum layers appeared in the sub-surface layer below thermocline. The phytoplankton community in the surface and stratified layers was composed of a total of 40 species belonging to 26 genera. Dominant species were 2 diatoms, Paralia sulcata, Skeletonema costatum and a dinoflagellate, Scripsiella trochoidea. Standing crops of phytoplankton in the surface layer were very low with cell density ranging from 5 to $3.8\;{\times}\;10^3\;cells/L$. Diatoms were controlled by the expanded low salinity coastal waters of the low salinity with high concentrations of nutrients. Otherwise phytoflagellates were dominant in the high temperature regions where the Tsushima warm currents approches the Southwestern Sea of Korea in early summer.

• Korean Journal of Environmental Biology
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• v.28 no.1
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• pp.30-39
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• 2010

We researched community structure, species composition, and habitat environment of Dendropanax morbifera populations distributed in Goheung, Haenam, Wando (I.), and Bogildo (I.) at south coast of the Korean Peninsula. Our research was also estimated possible area for growth of Dendropanax morbifera by analyzing meteorological factors of the habitat thereof. Dendropanax morbifera community divided into Castanopsis cuspidata var. sieboldii group and Carpinus laxiflora group by difference of species composition. Broad-leaved evergreens showed high dominance value in view of rNCD in Dendropanax morbifera community as follows: Camellia japonica (100.0), Quercus acuta (88.6), Castanopsis cuspidata var. sieboldii (55.8), Dendropanax morbifera Lev. (41.4), Trachelospermum asiaticum var. intermedium (23.8), Eurya japonica (19.9) and Ligustrum japonicum (11.5). In the population distribution, 94.2% of Carpinus laxiflora group consisted of sapling and small size class that are less than 5 cm in DBH while 54.2% of Castanopsis cuspidata var. sieboldii group did. The soil environment of habitat showed low soil acidity, good organic matter and water content, and good drainage. The distribution area of Dendropanax morifera habitat had $13^{\circ}C$ or more in annual mean temperature, $7.4^{\circ}C$ or more in daily minimum temperature, $100^{\circ}C$ month or more in warmth index, and approximately 1,344 mm in mean annual precipitation. Dendropanax morifera habitat corresponded to evergreen broad-leaved forest zone located in islands and coast in the southwest region of the Korean Peninsula. The northern limit line of Dendropanax morifera community was determined as Gunsan-Jeongeup-Gwangju-Jinju-Pohang-Youngdeok line based on $13^{\circ}C$ in annual mean temperature that was confirmed in natural habitat of Dendropanax morifera community.

• Journal of the Korean Magnetics Society
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• v.7 no.1
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• pp.13-18
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• 1997

The effects of the various raw material composition and sintered temperature on the physical properties of Ni-Zn ferrite have been investigated. They turned out to be spinel structure by X-ray diffraction and the size of grain from microscope was from 6 ${\mu}{\textrm}{m}$ to 16 ${\mu}{\textrm}{m}$. As the sintering temperature was increased from 1030 $^{\circ}C$ to 1070 $^{\circ}C$, the initial permeability and magnetic induction has increased and the both of Q factor and coercive force has decreased. The coercive force and curie temperature were almost the same at each specimen. Their values were about 0.20 Oe and 220 $^{\circ}C$. The frequency of specimen will used in the range from 400 kHz to 20 MHz. The basic composition of $Ni_{0.14}Zn_{0.64}Cu_{0.22}Fe_2O_4$ (specimen B) sintered at 1050 $^{\circ}C$ shows the best results at magnetic induction($B_r & B_m$).

• Economic and Environmental Geology
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• v.53 no.3
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• pp.307-320
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• 2020

This study focuses on the raw material characteristics, including firing temperature and the similarity of clay body, and making techniques on the underwater ceramics from offshore of Taean Mado, the Republic of Korea. The ceramic specimens include various types of celadons, Buncheongwares and white porcelains with very similar physical characteristics. All the clay bodies composed of same mineral phases within mullite and quartz, while cristobalite were also found in some white porcelains. Also, the geochemical composition of the clay body shows regular behavior properties for all the elements consisting of the celadons and Buncheongwares. In contrast, the irregular properties of trace and incompatible elements were found in white porcelains. Therefore, it is presumed that the white porcelains were made using the clay body with different source from the celadons and Buncheongwares. Notably, some white porcelains in low Th content are assumed to be made with clay formed in a different environments. Meanwhile, most of the ceramics had gone through the firing of 1,200 to 1,300℃, with some celadons fired from 1,150℃ to 1,200℃. Also, it can be interpreted as some white porcelains were fired on even up to 1,500℃.