• Journal of Korean Society of Forest Science
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• v.90 no.6
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• pp.717-724
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• 2001

This study was conducted in an attempt to quantify some traits that may be involved in the reproductive process of Pinus thunbergii. During the past 6 years (1995-2000), we surveyed flowering patterns of 60 P. thunbergii clones in a seed orchard which was established in Anmyon-do, 1979. From this survey, we estimated clonal contributions of male and female flowers and sexual asymmetry. Among 60 clones, 18 clones (30%) accounted for 0.37 (1999)~0.46 (1995) of clonal contribution in female flowers and 0.44 (1999)~0.57 (1995) of clonal contribution in male flowers. As compared with the previous reports in other pine species, more clones made contributions to reproductive process in P. thunbergii seed orchard. The relative effective population numbers for females (v♀) varied from 0.59 (1995) to 0.91 (1999) and those for males ( v♂) were between 0.56 (1995) and 0.83 (1998) at gamete level. This showed that the female gametes effectively contribute to the reproductive process more than did the male gametes. The relative effective population numbers at clonal level ($v_b$) were in the range of 0.72 (1995) and 0.93 (1999). More than 73% of the total clones showed values of 0.4~0.6 ($0.5{\pm}0.1$) in maleness index. The values averaged over all the clones were temporally variable with the range of 73% in 1996 and 100% in 2000. The degree of sexual asymmetry ($A_s$) ranged from 0.09 to 0.26. These values were relatively low when compared with those of other trees, suggesting that P. thunbergii seed orchard remains a high level of homogeneity in the number of male and female. All of the various types of effective population numbers were positively correlated with each other while they were negatively correlated with the degree of sexual asymmetry.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.4
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• pp.125-130
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• 2024

Preparation of ferromagnetic powders for the mixture of hematite and pure Mg powders by ball milling has been investigated. Also, consolidation of the ball-milled powders was performed in a spark plasma sintering machine at 800-1,000℃. It is found that a ferromagnetic Fe-MgO composite powders are obtained by ball milling of hematite and pure Mg powders before 1 hour. The magnetization and coercivity of ball-milled samples change at the results of the solid state reaction of hematite by pure Mg during ball milling. The saturation magnetization of ball-milled samples increases with increasing ball milling time and reaches to a maximum value of 93.4 emu/g after 5 hours of ball milling. Shrinkage change after sintering of ball-milled sample for 5 hours was significant above 300℃ and gradually increased with increasing temperature up to 800℃. X-ray diffraction result shows that the average grain size of Fe in Fe-MgO bulk sample sintered at 900℃ is 50 nm. It can be also seen that the coercivity of bulk sample sintered at 900℃ is still high value of 90 Oe, indicating that the grain growth of magnetic Fe phase during sintering process tend to be suppressed.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.129-138
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• 2006

Helicopter-borne aeromagnetic surveys at two different times separated by three years were conducted to better understand the shallow subsurface structure of the Vulcano and Lipari volcanic complex, Aeolian Islands, southern Italy, and also to monitor the volcanic activity of the area. As there was no meaningful difference between the two magnetic datasets to imply an apparent change of the volcanic activity, the datasets were merged to produce an aeromagnetic map with wider coverage than was given by a single dataset. Apparent magnetisation intensity mapping was applied to terrain-corrected magnetic anomalies, and showed local magnetisation highs in and around Fossa Cone, suggesting heterogeneity of the cone. Magnetic modelling was conducted for three of those magnetisation highs. Each model implied the presence of concealed volcanic products overlain by pyroclastic rocks from the Fossa crater. The model for the Fossa crater area suggests a buried trachytic lava flow on the southern edge of the present crater. The magnetic model at Forgia Vecchia suggests that phreatic cones can be interpreted as resulting from a concealed eruptive centre, with thick latitic lavas that fill up Fossa Caldera. However, the distribution of lavas seems to be limited to a smaller area than was expected from drilling results. This can be explained partly by alteration of the lavas by intense hydrothermal activity, as seen at geothermal areas close to Porto Levante. The magnetic model at the north-eastern Fossa Cone implies that thick lavas accumulated as another eruption centre in the early stage of the activity of Fossa. Recent geoelectric surveys showed high-resistivity zones in the areas of the last two magnetic models.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.27-32
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• 2008

Detailed bathymetry and magnetic survey data for Esmeralda Bank obtained by R/V Onnuri of Korea Ocean Research & Development Institute in September 2007 were analyzed to estimate the locations of possible hydrothermal vents. The shape of Esmeralda Bank is caldera type opened in the western part. The summit is very shallow, about 50 meter b.s.l. and the bottom is about 1300 meter b.s.l. The western part of Esmeralda Bank is more steeper and topographic irregular than eastern part, and showed the valley made by erosion or collapse. The magnetic anomaly patterns of Esmeralda Bank located low anomalies over the north and high anomalies over the south. The magnetic anomalies are steep over the summits and gently smooth over the deep bottom. Two low magnetization zones are located in the summit and westside of Esmeralda Bank. The low magnetization zones of the summits of Esmeralda Bank suggest the possible existence of hydrothermal vent.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.100-108
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• 1989

Thirty-six aromatic compound biodegraders; 10 strains for benzoate, 10 for salicylate, 6 for m-toluate, and 10 for DL-camphor were isolated and taxonomically characterized. A mutant Pseudomonas strain, Ben 6-2, derived from Ben 6 revealed remarkably improved ability to metabolize benzoate. Thus enhancement of the average substrate removal rate from 5.2 to 11.0mg/$\ell$/ hr was attained by the mutant. Both of strains Sal 7 and Tol 2, degraders of salicylate and m-toluate respectively, were classified as Pseudomonas sup. Both strains were found to be extremely effective in metabolizing each aromatic substrates. The average substrate degradation rates in minimal salt media containing 2,200mg/$\ell$ of the substrate were calculated to be 40.1 mg/$\ell$/ hr for strain Sal 7 and 33.0mg/$\ell$/ hr for Tol 2. Cam 10, a camphor degrading strain was demonstrated to be capable of mineralizing benzoate, phenol, toluene, octane, cyclohexane and xylene as well as camphor. Strain 1040 isolated from Cam 10 after repented adaptation to 1,000 mg/$\ell$ m-toluate gained the ability to utilize toluate as a sole carbon source. The mutant Brew actively at the expense of a mixture of car-bon sources; camphor, m-toluate, benzoate and phenol (each: 200 mg/$\ell$) and utilized the substances in the preferential order of camphor, phenol, benzoate, and m-toluate. Among the biodegraders examined Cam 1040 and Tol 2 were detected to harbor plasmid. The plasmid from Cam 1001 was determined to be about 98kb, and evidenced to encode the enzyme(s) for the degradation of camphor. For the further diversification of the metabolic potentials of Cam 1040, the NAH 2 plasmid of Pseudomonas putida NCIB 9816 was transferred to Cam 1040 by conjugation. The exconjugant obtained, Cam 1043, proved to gain an additional ability to metabolize salicylate and naphthalene.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.207-216
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• 2013

This study was conducted to establish the method for preserving PGCs that enables long-term storage in liquid nitrogen for developmental engineering or preservation of species. The purpose of this study is to clarify the effects of freeze-thaw treatment on viability of PGCs in chickens. PGCs were collected separately from a germinal gonad of an early embryo of 5.5~6 day (stage 28) of Isa brown, Korean Oge (KO), White Leghorn and Commercial breeds. PGCs separated from a germinal gonad of an early embryo of 5.5~6 day (stage 28) are suspended in a freezing medium containing a freezing and protecting agents (e.g. dimethyl sulfoxide (DMSO), ethylene glycol (EG) and glycerol). The PGCs were then purified using magnetic activated cell sorting (MACS) method. The viability of PGCs after thawing was $87.4{\pm}0.4%$ and $89.4{\pm}0.2%$ with the 10% EG treatments with no significant difference between the Isa brown and Commercial breeds. The viability of PGCs after freeze- thawing was significantly higher for Isa brown ($87.4{\pm}0.4%$) and Commercial breeds ($89.4{\pm}0.2%$) than Korean Oge (KO) ($77.6{\pm}1.1%$) and White Leghorn ($76.2{\pm}0.9%$)(p<0.05) using 10% EG cryoprotectant. This study established a method for pre- serving chicken PGCs that enables systematic storage and labeling of cryopreserved PGCs in liquid ($LN_2$) at agermplasm repository and ease of entry into a data base. In the future, the importance for this new technology is that poultry lines can be conserved while work is being conducted on improving the production of germline chimeras.

• Journal of the Korean Magnetics Society
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• v.18 no.3
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• pp.109-114
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• 2008

The samples were synthesized by using a solid state reaction. The X-ray diffraction pattern for $Ti_{0.96}Co_{0.02}Fe_{0.02}O_2$ showed a pure rutile phase with tetragonal structure, Mixtures of the proper proportions of the elements sealed in evacuated quartz ampoule were heated at $870{\sim}930^{\circ}C$ for one day and then slowly cooled down to room temperature at a rate of $10^{\circ}C$/h. In order to obtain single phase material, it was necessary to grind the sample after the first firing and to press the powders into pellets before annealing them for a second time in evacuated and sealed quartz ampoule. Magnetic properties have been investigated using the vibrating sample magnetometer (VSM). Room temperature magnetic hysteresis (M-H) curve showed an obvious ferromagnetic behavior and the magnetic moment per Fe atom under the applied of 0.8 T was estimated to be about $1.5\;{\mu}_B$/CoFe. But the magnetic moment per Fe atom under the applied of 0.8 T was estimated to be about $0.02\;{\mu}_B$/CoFe without Ti-getter. Size of particles is about $1\;{\mu}m$ using the transmission electron microscope (TEM). The ingredients of sample are distributed irregular in particles. Only Fe get shown on the surface of particles.

• Journal of the Korean Magnetics Society
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• v.15 no.3
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• pp.186-190
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• 2005

The $Al_{0.2}CoFe_{1.8}O_4$ ferrite films and powders were prepared by the sol-gel method. The crystallographic and magnetic properties of the samples were examined with annealing temperature by X-ray diffraction, $M\ddot{o}ssbauer$ spetroscopy and vibrating sample magnetometry. The powder samples showed the presence of spinel structure at annealing temperatures above 673 K, while the film samples indicated the spinel structure above 873 K, also the particle size increased with rising annealing temperatures. The $M\ddot{o}ssbauer$ spectra of $Al_{0.2}CoFe_{1.8}O_4$ powder annealed above 873 K could be fitted as the superposition of two Zeeman sextets due to ferrimagnetic phase. And the spectra of annealed at 673 K exhibited the superposition of ferrimanetic and paramagnetic phase and those of annealed at 473 K showed only a paramagnetic phase. The magnetic behaviour of powders appeared that the coercivity increased until annealed at 673 K but decreased above this temperature. The coercivity of the film samples decreased from 1.084 kOe at 873 K to 0.540 kOe at 1073 K with increasing annealing temperatures.

• Composites Research
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• v.36 no.5
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• pp.289-296
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• 2023

In this study, we investigated the electromagnetic properties and microwave absorption characteristics of M-type hexagonal ferrites, which are known as millimeter-wave absorbing materials, according to their calcination temperature. The M-type ferrites synthesized using a molten salt-based sol-gel method exhibited a single-phase M-type crystal structure at calcination temperatures above 850℃. The synthesized particle size increased as well with the calcination temperature. Saturation magnetization increased gradually with increasing calcination temperature, but coercivity reached a maximum at 1050℃ and then rapidly decreased. After preparing a thermoplastic polyurethane (TPU) composite containing 70 wt% of M-type ferrites, we measured the complex permittivity and permeability in the Q-band (33-50 GHz) and V-band (50-75 GHz) frequency ranges, where ferromagnetic resonance occurred. Strong magnetic loss from ferromagnetic resonance occurred in the 50 GHz band for all composite samples. Based on the measured results, we calculated the reflection loss of the TPU/M-type ferrite composite. By calculating the reflection loss of the M-type ferrite composite, the M-type ferrite calcined at 1250℃ showed excellent electromagnetic wave absorption performance of more than -20 dB at 52 GHz with a thickness of about 0.5 mm.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.10
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• pp.1535-1542
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• 2014

This study was conducted to investigate the physicochemical properties and biological activities of collagens with different molecular weights from Alaska pollack (Theragra chalcogramma) skin as well as their efficacies as functional materials. The molecular weights of collagens were between 1~10 kDa (below 1 kDa (AP1), 1~3 kDa (AP2), 3~10 kDa (AP3), and above 10 kDa (AP4). The protein content of AP4 (40.19 g/100 g) was the highest. Collagen contents of AP1, AP2, AP3, and AP4 were 36.43, 32.23, 19.23, and 14.89%, respectively. The free amino acid and essential amino acid contents of AP1 were higher than those of AP2, AP3, and AP4. Fourier transform infrared spectroscopy spectra of collagens with different molecular weights showed wavenumbers representing the regions of amide I, amide II, amide III, and amide A, respectively. The electron-donating ability (29.51%) and SOD-like activity (38.45%) of AP1 were higher than those of AP2, AP3, and AP4. Tyrosinase inhibition activity of AP1 improved with higher treatment concentration. The rate of inhibition of MMP-1 production in HS68 cells exposed to UVB was suppressed by treatment with AP1 (29.78%) and AP2 (26.49%) at 1 mg/mL. Furthermore, there was a strong correlation between DPPH, superoxide dismutase, tyrosinase activity, and MMP-1 inhibition rate of collagens with different molecular weights.