• Journal of the Korean Magnetics Society
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• v.23 no.4
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• pp.122-125
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• 2013

Perpendicular magnetic anisotropy (PMA) is the phenomenon of magnetic thin film which is preferentially magnetized in a direction perpendicular to the film's plane. Amorphous multilayer with PMA has been studied as the good candidate to realization of high density STT-MRAM (Spin Transfer Torque-Magnetic Random Access Memory). The current issue of high density STT-MRAM is a decrease in the switching current of the device and an application of amorphous materials which are most suitable devices. The amorphous ferromagnetic material has low saturated magnetization, low coercivity and high thermal stability. In this study, we presented amorphous ferromagnetic multilayer that consists of an amorphous alloy CoSiB and a nonmagnetic material Pd. We investigated the change of PMA of the $[CoSiB\;t_{CoSiB}/Pd\;1.3nm]_5$ multilayer ($t_{CoSiB}$ = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 nm, and $t_{Pd}$ = 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6 nm) and $[CoSiB\;0.3nm/Pd\;1.3nm]_n$ multilayer (n = 3, 5, 7, 9, 11, 13). This multilayer is measured by VSM (Vibrating Sample Magnetometer) and analyzed magnetic properties like a coercivity ($H_c$) and a magnetization ($M_s$). The coercivity in the $[CoSiB\;t_{CoSiB}\;nm/Pd\;1.3nm]_5$ multi-layers increased with increasing $t_{CoSiB}$ to reach a maximum at $t_{CoSiB}$ = 0.3 nm and then decreased for $t_{CoSiB}$ > 0.3 nm. The lowest saturated magnetization of $0.26emu/cm^3$ was obtained in the $[CoSiB\;0.3nm/Pd\;1.3nm]_3$ multilayer whereas the highest coercivity of 0.26 kOe was obtained in the $[CoSiB\;0.3nm/Pd\;1.3nm]_5$ mutilayer. Additional Pd layers did not contribute to the perpendicular magnetic anisotropy. The single domain structure evolved in to a striped multi-domain structure as the bilayer repetition number n was increased above 7 after which (n > 7) the hysteresis loops had a bow-tie shapes.

• Journal of Plant Biology
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• v.28 no.2
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• pp.105-118
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• 1985

This study was carried out to investigate the epidermal structure and types of stomata on the upper and lower surfaces of the leaves in six species and one variety belonging to Korean Crassulaceae. The shape of epidermal cells was polygonal, isodiametric, or elongated. The cell wall was thick, sinuous or deeply sinuous. The subsidiary cell wall was thin or mostly arched. The cytolith-containing cells were found in Orostachys japonicus. The distribution of stomata was more on the upper surface than on the lower surface in the leaves of O. japonicus and Sedum sarmentosum. The stomata in the other species were less on the upper surface than on the lower surface, and stomatal size was different in each species. The great majority of stomatal types was the helico-eumesogenous type. This type was subdivided into two, parahelico-eumesogenous type and diahelico-eumesogenous type by us on the basis of the angle of division of guard mother cell and the long axis of the last-formed subsidiary cells. Sometimes allelo-eumesogenous type as well as aniso-eumesogenous type was found. The tetra-eumesogenous type with four mesogenous subsidiary cells was rarely observed. It was observed that the varieties of aniso-eumesogenous type with one to three subsidiary cells and one helix of subsidiary cells were developed by the secondary division of subsidiary cells of aniso-eumesogenous stoma. The compound shape of helico-eumesogenous stomata was found. Five new kinds of stomatal types were observed as follows; the helico-tetra-eumesogenous type, the coallelohelico-eumesogenous type, the cohelico-allelo-eumesogenous type, the duplotetra-eumesogenous type, and the aniso-euperigenous type. These types were reported here in the vascular plants for the first time.

• Food Science and Preservation
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• v.20 no.4
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• pp.573-582
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• 2013

This study was done in order to investigate the bioconversion of ginsenoside, as well as the quality characteristics of fermented ginseng, by using lactic acid bacteria. Quality characteristics such as the thin layer chromatography(TLC) pattern, ginsenosides, total phenolic content, electron donating ability, and total sugar of fermenting ginseng and red ginseng were analyzed. The ginsenoside Rg2r, Rh2s and Rh2r of the fermented ginseng and red ginseng for 65 hours at a temperature of $37^{\circ}C$ were not detected. The ginsenoside Rg1 and Re contents have decreased, while the Rh1, Rg2s, Rd, Rg3r, and Rg3s have increased due to fermentation. The ginsenoside Rg3 of the fermented red ginseng has increased and the contents were $114.83{\sim}131.68{\mu}g/mL$ (control $104.56{\mu}g/mL$). The total phenolic content and electron donating ability of the red ginseng have totally decreased after 7 days of fermentation. The total phenolic contents of the fermented ginseng and red ginseng with different lactic acid bacteria did not show any tendency as different strains. The electron donating ability of the fermented ginseng has increased; however, the electron donating ability of the red ginseng has decreased. The total sugars of the fermented ginseng and red ginseng with different lactic acid bacteria have also decreased.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.6
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• pp.1-6
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• 2011

A transparent oxide thin film transistors (Transparent Oxide-TFT) have been fabricated by RF magnetron sputtering at room temperature using amorphous indium zinc oxide (a-IZO) as both of active channel and source/drain, gate electrodes and co-sputtered $HfO_2-Al_2O_3$ (HfAIO) as gate dielectric. In spite of its high dielectric constant > 20), $HfO_2$ has some drawbacks including high leakage current and rough surface morphologies originated from small energy band gap (5.31eV) and microcrystalline structure. In this work, the incorporation of $Al_2O_3$ into $HfO_2$ was obtained by co-sputtering of $HfO_2$ and $Al_2O_3$ without any intentional substrate heating and its structural and electrical properties were investigated by x-ray diffraction (XRD), atomic force microscopy (AFM) and spectroscopic ellipsometer (SE) analyses. The XRD studies confirmed that the microcrystalline structures of $HfO_2$ were transformed to amorphous structures of HfAIO. By AFM analysis, HfAIO films (0.490nm) were considerably smoother than $HfO_2$ films (2.979nm) due to their amorphous structure. The energy band gap ($E_g$) deduced by spectroscopic ellipsometer was increased from 5.17eV ($HfO_2$) to 5.42eV (HfAIO). The electrical performances of TFTs which are made of well-controlled active/electrode IZO materials and co-sputtered HfAIO dielectric material, exhibited a field effect mobility of more than $10cm^2/V{\cdot}s$, a threshold voltage of ~2 V, an $I_{on/off}$ ratio of > $10^5$, and a max on-current of > 2 mA.

• Journal of the Korean Magnetics Society
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• v.13 no.5
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• pp.187-192
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• 2003

The magnetic and thermal properties of NiFe/[IrMn-Mn]/CoFe with Mn additions have been studied. As-deposited CoFe pinned layers with [IrMn-Mn]layer had dominantly larger exchange biasing field ( $H_{ex}$) and blocking temperature ( $T_{b}$) than those with pure I $r_{22}$M $n_{78}$ used. The $H_{ex}$ and $T_{b}$ improved with 76.8-78.1 vol% Mn, but those of the NiFe/IrMn/CoFe dropped considerably with more addition of 0.6 vol % Mn. The average x-ray diffraction peak ratios of fcc [(111)CoFe, NiFe]/(111)IrM $n_3$ textures for the Mn inserted total vol of 75.5, 77.5, and 79.3% were about 1.4, 0.8, and 0.6, respectively. For the sample without Mn inserted layer, the $H_{ex}$ between IrMn and CoFe layers was almost zero, but it increased to 100 Oe after annealing of 250 $^{\circ}C$. For as-grown two multilayers samples with ultra-thin Mn layers of 77.5 and 78.7 vol %, the $H_{ex}$s were 259 and 150 Oe, respectively. In case of IrMn with 77.5 vol% Mn, the $H_{ex}$ was increased up to 475 Oe at 350 $^{\circ}C$ but decreased to 200 Oe at 450 $^{\circ}C$, respectively. The magnetic properties and thermal stabilities of NiFe/[IrMn-Mn]/CoFe multilayer were enhanced with Mn additions. In applications where higher $H_{ex}$ and $T_{b}$ are required, proper contents of Mn can be used. be used. used.

• Journal of The Korean Astronomical Society
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• v.24 no.2
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• pp.217-271
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• 1991

We have observed dense core around young stellar objects, DR21, S140, Orion-KL, and L1551 using four millimeter-wave transitions of $HC_3N\;J$=4-3, J=5-4, J=10-9, and J=12-11. The spatial distribution of $HC_3N$ emission closely resembles the morphology of the previous CS observations that trace high density gas. These observations reveal the existence of $HC_3N$ dense cores around central IR source, elliptical in shape and almost perpendicular to the CO bipolar outflow axis. Small differences can be explained by that $HC_3N$ molecular line is more optically thin and is seen to be more detailed structure in the neighborhood of central IR sources. In S140 and Orion-KL, massive(${\sim}10\;M_{\odot}$), slowly rotating dense cores lie near at the central IR sources of bipolar outflows. The velocity channel maps of DR21 show that the bipolar outflow gas may have a correlation with the dense core of DR21. We analyzed intensities of the four lines to derive physical conditions in dense core from two methods, LTE and LVG. The column density of $HC_3N$, $N(HC_3N)$, between LTE and LVG calculations agree well with each other. The abundances of $HC_3N$ in each observing source have been estimated using the average values of $n(H_2)$ and $N(HC_3N)$ and assuming the size of dense core. The fractional $HC_3N$ abundances in massive dense cores of DR21, S140, and Orion-KL have a range of $(2-7){\times}10^{-10}$, while that of low mass dense core, L1551, has one order of magnitude greater value of $2{\times}10^{-9}$. This should be considered good agreement with the result by Morris et al.(1976). It may be considered that dense cores of DR21, S140, and Orion-KL may have almost same stage of chemical evolution, and their abundances have a small values relative to that of L1551. The column density $N(HC_3N)$ decreases with increasing distance from the densest part of the cloud, the central infrared source, and have the relation of $N(HC_3N){\varpropto}R^{\alpha}$, where a has a range of 0.65 to 0.89. The values of $n(H_2)$ are not varied with increasing distance from the dense core, and have almost same values. Therefore, it is considered that the dense cores in these regions probably consist of dense clumps in diffuse molecular gas medium, and $n(H_2)$ of each clump is ${\sim}10^5\;cm^{-3}$. Levels in the $T_{ex}$ increases with $n(H_2)$. It is considered that the $HC_3N$ dense cores are not completely thermalized. We examine the relationships between the luminosity of central infrared sources versus mass of the dense cores, and the luminosity of central infrared sources versus molecular hydrogen column density. Luminosities of the central IR sources show good correlation with mass and hydrogen column density of the dense core. Same has been found from CS observations. However, mass and size derived from $HC_3N$ observations are one order of magnitude smaller than those from CS. It can be interpreted that we see more central part of the cloud cores in $NC_3N$ lines than CS lines.

• Tuberculosis and Respiratory Diseases
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• v.52 no.2
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• pp.179-185
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• 2002

A bronchus-associated lymphoid tissue(BALT) lymphoma of the lung is a rare disorder of patients with Sj$\ddot{o}$gren's syndrome. A 49-year-old woman was admitted for an evaluation of exertional dyspnea and general weakness which had persisted for two years. The patient had suffered from dry mouth and dry eyes for five years. The physical examinations showed a coarse breath sound with inspiratory crackles on the whole lung field, particularly on the both basal lungs. The laboratory data disclosed high titers of anti-nuclear antibodies, and anti-SSA (Ro), and anti-SSB (La) antibodies. Chest radiographs demonstrated the presence of bilateral, diffuse, reticulonodular densities in both lungs. Thin-section CT scans showed diffusely distributed mosaic pattern of an inhomogeneous attenuation extending over the entire lung zone. The histological findings from an open-lung biopsy specimen revealed an accumulation of lymphoid cells around the bronchioles and an extension of malignant lymphoma cells from the bronchiolar epithelium toward the alveolar space. Immunohistochemically, the neoplastic cells reacted positively to the CD 20 antigen and were focally positive for the UCHL 1 antigen. The histological diagnosis was consistent with a low grade marginal zone B-cell lymphoma originating in the BALT. Here, we present a case of a histologically proven BALT lymphoma of the lung in a patient with primary Sj$\ddot{o}$gren's Syndrome.

• Journal of The Korean Association For Science Education
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• v.22 no.2
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• pp.299-313
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• 2002

A web-based instruction program for the enriched course under the 7th Revised National Curriculum of Biology in Korea was developed and the application effects to learners were analyzed. For the development of the web-based instruction program, five topics of biology from the enriched courses through 7th to 10th grades in the middle and high school science textbooks were selected and modulated with interrogative sentences. Each topic of programs was divided into four activity sections according to the learners' activity procedures supplemented with explanations and evaluations. Each activity was hyper-linked to multi-layers and animations. Further, a virtual experiment was also developed and an evaluation section designed by Java Script was attached. Among five topics, one topic of 'Reproduction and development' at 9th grade level was selected to examine the effects on students' learning. Among 247 9th grade students in the research subject school, only 67 students were able to accessible to ultra-thin Internet cables with their computers at home and they became an experimental group. A control group was assigned to those who are similar level of school science achievement to the experiment group and did not use the web-based program. It was found that most of 9th grade students are able to use Internet at home, however, they do not prefer to use Internet for homework or task project. Rather, most of students used Internet for e-mail or information navigation. Students used internet to solve problems of science and perceived the benefits of Internet for science learning. However, there are not many students to utilize Internet for science homework or task project. Students expressed that they do not prefer to use a web-based learning program for science learning due to lack of interests in science. The effects on students who studied with this program appeared to be significantly high compared to those who did not study with this program. Students who studied with this program positively evaluated this program, in particular, they enjoyed animation effect and virtual experiments. It was concluded that a web-based program for science learning should be developed and distributed through Internet in an attractive and interesting format for students. It was also concluded that various web-based programs for science learning with animation effect and virtual experiments should be developed to increase students' interests in science as well as to improve students' science achievements.

• The Journal of the Petrological Society of Korea
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• v.26 no.2
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• pp.127-141
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• 2017

Jurassic granite from Geochang was analysed with respect to the characteristics of the rock cleavage. The multicriteria evaluation for the six directions of rock cleavages was performed using the microcrack spacing-related parameters derived from the enlarged photomicrographs (${\times}6.7$) of the thin section and the spacing-cumulative frequency diagrams. The results of analysis for the representative values of these spacing parameters with respect to the rock cleavage are summarized as follows. First, the analysis for deriving the main parameter indicating the order of arrangement among six diagrams was performed. The values of five parameters with respect to six directions of the rock cleavages were arranged in increasing or decreasing order for the above analysis. The decreasing order of the values of main parameter(mean spacing-median spacing, $S_{mean}-S_{median}$) and mean spacing are consistent with the order of H1, H2, G1, G2, R1 and R2 directions. These sequential arrangements of six directions of the rock cleavages can provide a basis for those of the six diagrams related to spacing. Second, the nine correlation charts between the above main parameter and various parameters were arranged in decreasing order of correlation coefficient ($R^2$). These related charts shows a high correlation of power-law function in common. The values of mean spacing, density (${\rho}$) and length of line oa are directly proportional to the value of main parameter, while the values of constant (a), exponent (${\lambda}$), spacing frequency (N), length of line oa', slope of exponential straight line (${\theta}$) and total length ($1mm{\geq}$) are inverse proportional. Third, the results of correlation analysis between the values of parameters for three planes and those for three rock cleavages are as follows. The values of frequency, total spacing, constant, exponent, slope and length of line oa' for three planes and three rock cleavages show an order of R' < G' < H' and H < G < R, respectively. On the other hand, the values of mean spacing, (mean spacing-median spacing), density and length of line oa show an order of H' < G' < R' and R < G < H, respectively. The correlation of the mutually reverse order of the values of parameters between three planes and three rock cleavages can be drawn. This type of correlation analysis is useful for discriminating three quarrying planes.

• Korean Journal of Food Science and Technology
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• v.11 no.4
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• pp.304-313
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• 1979

The compositions of the polar lipids in the free and bound lipids from four varieties of experimentally cultivated potatoes were identified and quantified by thin layer- and gas-liquid chromatographies. The results were summarized as follows : 1. The glycolipids contained in the free and bound lipids were fractionated and identified as esterified sterol glycoside, monogalactosyl diglyceride, sterol glycoside, digalactosyl diglyceride, and trigalactosyl diglyceride, of which the highest content to the total lipid quantity were 5.8% of esterified sterol glycoside in the free lipid and 6.1% of trigalactosyl diglyceride in the bound lipid. The content of monogalactosyl diglyceride in the free and bound lipids was almost the same, whereas the content of esterified sterol glycoside was higher in the free lipid than in the bound lipid, and the contents of sterol glycoside, digalactosyl diglyceride, and trigalactosyl diglyceride were higher in the bound lipid than in the free lipid on the contrary. 2. The phospholipid contained in the free and bound lipids were fractionated and identified as phosphatidyl ethanolamine, phosphatidyl glyceride, phosphatidyl choline, and phosphatidyl inositol, but the phosphatidyl glyceride was not detected in the free lipid. The highest content in the total lipid quantity was 3.3 % of phosophatidyl choline in the case of the free lipid, while 14.9 % of the phosphatidyl ethanolamine contained in the bound lipid was the highest. All other constituents of phospholipid were contained in larger quantity in the bound lipid than in the free lipid. 3. The fatty acid composition of glycolipid in the free and bound lipids was also the same as that of the total free and bound lipids. The differences were that the content of palmitic acid was higher in the glycolipid of the free lipid than in the total free lipid and the content of linoleic acid was lower in the glycolipid.