• Journal of Korean Society of Forest Science
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• v.78 no.4
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• pp.401-411
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• 1989

The embryos of Pinus taeda, P. rigida, and P. taeda ${\times}$ rigida were cultured for adventitious shoot regeneration in vitro. Culture media were modified from Gresshoff and Doy (MGD), Murashige and Skoog (MMS), Lloyd and McCown (MLM), and Schenk and Hildebrandt (MSH). NAA was added to initiation media at a concentration of 0.1 or 0.01 mg/l. BAP was used at the concentrations of 0.1. 0.5, 1, 2, or 5mg/l. Each explant was induced for 3-4 weeks on solid medium. All explants were cultured up to 16 weeks. Illumination was about $1506{\pm}540lux$ at the level of the tissues in the growth room with a temperature of $25{\pm}2^{\circ}C$. A 16-hour photoperiod per 24 hours was used. Half-strength medium was used for all the subcultures. For shoot production by loblolly pine, MMS, MLM, or MSH is preferred with 5 mg/l BAP with either 0.1 or 0.01 mg/l NAA. For shoot production by pitch pine, MMS, MLM, or MSH is recommended with 2 or 5 mg/l BAP with 0.1 mg/l NAA. For shoot production by the hybrid pine, MMS or MLM is more effective with 1, 2 or 5 mg/l BAP with 0.1 mg/l NAA. There were no differences recognized among the species tried in the patterns of bud formation and shoot development. Different composition of media, in major and minor salts or possibly in vitamins, should be tested for the two developmental stages of adventitious shoots ; the induction of shoot buds and the elongation of them into shoots.

• Journal of the Korean Society of International Agriculture
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• v.31 no.2
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• pp.178-182
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• 2019

'Muha' is a new strawberry (Fragaria x ananassa Duch.) cultivar, which was released by the Highland Agriculture Research Institute in 2015. The 'Muha' cultivar originated from a cross between 'Maehyang' and 'Selva' that showed excellent ever-bearing characteristics, including continuous flowering habit and high soluble-solid content under long-day and high temperature conditions in 2010. This cultivar was initially named 'Saebong No. 7' after examining its characteristics and productivity in summer culture from 2011 to 2014. After regional adaptability tests in 2015, 'Muha' was selected from Saebong No. 7 as an elite cultivar. The general characteristics of 'Muha' include semispreading type, elliptical leaf, and strength vigor in growth. The fruits are conical in shape, red in color. 'Muha' plants have 18.7 flower clusters, 8.7 more than 'Flamenco' plants. The fruit hardness of 'Muha' and Flamenco' was about the same. The number of fruits of 'Muha' was 37.2, which was 20 higher than that of 'Flamenco'. The marketable yield was 23,981 kg·ha^-1, 159% higher than 'Flamenco'. 'Muha' is suitable for north and highland area of the Southeast Asia as a high hardness and yield cultivar, because it showed continuous flowering habit under long-day and high temperature conditions.

• Journal of Embryo Transfer
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• v.23 no.4
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• pp.269-274
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• 2008

The purpose of this study was to determine the effects of Taxol pre-treatment to in vitro matured bovine oocytes, and sucrose and trehalose added to vitrification solution on spindle morphology and embryonic development following cryopreservation. Bovine oocytes were collected from ovaries and matured in tissue culture medium 199 (TCM 199) supplemented with 10% Fetal Bovine Serum (FBS), 0.05ng/ml epidermal growth factor, 0.01 IU/ml luteinizing hormone and $1{\mu}g/ml$ estradiol for 22h in $39^{\circ}C$, 5% $CO_2$, TCM 199-HEPES containing 20% FBS was used as basic medium (BM) to prepare vitrification solution. Oocytes were pre-treated with $1\;{\mu}M$ Taxol in maturation medium for 15 min prior to vitrification. Oocytes were exposed to 1.6 M ethylene glycol (EG) and 1.3M dimethyl sulfoxide (DMSO) in BM and then were exposed to 3.2 M EG, 2.6 M DMSO and 0.5 M sucrose in BM or 3.2 M EG, 2.6 M DMSO and 0.5 M trehalose in BM. Oocytes with cumulus cells and oocytes without cumulus cells were considered as control 1 and control 2, respectively and held in TCM 199-HEPES at $39^{\circ}C$. Oocytes were frozen using modified solid surface vitrification and were stored in cryotubes in liquid nitrogen for more than 1 week. Frozen oocytes were thawed in TCM 199-HEPES containing 0.5 M, 0.25 M and 0.1 M sucrose in BM for 2 min, respectively or 0.5 M, 0.25 M and 0.1 M trehalose in BM for 2 min, respectively. Immunoflurorescence staining of oocytes was performed to assess spindle morphology and chromosome configuration of oocytes. The rates of cleavage and blastocyst were examined following in vitro fertilization. Normal spindle morphology rate of oocytes pre-treated with Taxol prior to vitrification was not higher than that of other vitrified groups. Taxol pre-treatment did not increase cleavage and blastocyst formation rates, although control groups showed significantly higher rates (p<0.05). Percentages of normal spindle and embryonic development were not significantly different among vitrified groups regardless of type of sugar. In conclusion, Taxol pre-treatment of oocytes before cryopreservation did not reduce the damage induced by vitrification and subsequently did not improve embryonic development following vitrification. Trehalose may be used as an alternative non-permeating cryoprotectant in vitrification solution.

• Journal of Powder Materials
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• v.9 no.6
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• pp.394-408
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• 2002

Nanostructured high strength metastable Al-, Mg- and Ti-based alloys containing different amorphous, quasicrystalline and nanocrystalline phases are synthesized by non-equilibrium processing techniques. Such alloys can be prepared by quenching from the melt or by powder metallurgy techniques. This paper focuses on one hand on mechanically alloyed and ball milled powders containing different volume fractions of amorphous or nano-(quasi)crystalline phases, consolidated bulk specimens and, on the other hand. on cast specimens containing different constituent phases with different length-scale. As one example. $Mg_{55}Y_{15}Cu_{30}$- based metallic glass matrix composites are produced by mechanical alloying of elemental powder mixtures containing up to 30 vol.% $Y_2O_3$ particles. The comparison with the particle-free metallic glass reveals that the nanosized second phase oxide particles do not significantly affect the glass-forming ability upon mechanical alloying despite some limited particle dissolution. A supercooled liquid region with an extension of about 50 K can be maintained in the presence of the oxides. The distinct viscosity decrease in the supercooled liquid regime allows to consolidate the powders into bulk samples by uniaxial hot pressing. The $Y_2O_3$ additions increase the mechanical strength of the composites compared to the $Mg_{55}Y_{15}Cu_{30}$ metallic glass. The second example deals with Al-Mn-Ce and Al-Cu-Fe composites with quasicrystalline particles as reinforcements, which are prepared by quenching from the melt and by powder metallurgy. $Al_{98-x}Mn_xCe_2$ (x =5,6,7) melt-spun ribbons containing a major quasicrystalline phase coexisting with an Al-matrix on a nanometer scale are pulverized by ball milling. The powders are consolidated by hot extrusion. Grain growth during consolidation causes the formation of a micrometer-scale microstructure. Mechanical alloying of $Al_{63}Cu_{25}Fe_{12}$ leads to single-phase quasicrystalline powders. which are blended with different volume fractions of pure Al-powder and hot extruded forming $Al_{100-x}$$(Al_{0.63}Cu_{0.25}Fe_{0.12})_x$ (x = 40,50,60,80) micrometer-scale composites. Compression test data reveal a high yield strength of ${\sigma}_y{\geq}$700 MPa and a ductility of ${\varepsilon}_{pl}{\geq}$5% for than the Al-Mn-Ce bulk samples. The strength level of the Al-Cu-Fe alloys is ${\sigma}_y{\leq}$550 MPa significantly lower. By the addition of different amounts of aluminum, the mechanical properties can be tuned to a wide range. Finally, a bulk metallic glass-forming Ti-Cu-Ni-Sn alloy with in situ formed composite microstructure prepared by both centrifugal and injection casting presents more than 6% plastic strain under compressive stress at room temperature. The in situ formed composite contains dendritic hcp Ti solid solution precipitates and a few $Ti_3Sn,\;{\beta}$-(Cu, Sn) grains dispersed in a glassy matrix. The composite micro- structure can avoid the development of the highly localized shear bands typical for the room temperature defor-mation of monolithic glasses. Instead, widely developed shear bands with evident protuberance are observed. resulting in significant yielding and homogeneous plastic deformation over the entire sample.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.1-6
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• 2007

Effect of BA concentrations and culture methods on in vitro plant multiplication from shoot-tip cultures of Wasabia japonica was studied. Shoot-tips with leaf primordia and apical meristem were cultured on MS basal medium for all the experiments. Liquid medium for 2 weeks followed by semi-solid medium for 4 weeks containing 1.0 mg/L BA was the best to number of shoots (22.8) and shoot length (3.5 cm). Shoots proliferated could be divided into ca. 5 to 11 of cultures for the multiplication of plantlets. Divided plantlets showed root formation (90%) well onto MS basal medium without growth regulators like IBA and NAA. After rooting, all the plantlets transferred into the pots containing composed soil (bio-media Co., peatmoss $8{\sim}10%$, coir dust $66{\sim}70%$, zeolite $13{\sim}17%$, vermiculite $3{\sim}7%$, perlite $2{\sim}4%$) and grown well into whole plants with multiple shoots.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.1036-1043
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• 1994

The silane crosslinking method was applied for the crosslinking of polyethylene (PE). Crosslinking of PE was performed by, first grafting vinyltrimethoxysilane(VTMOS) to the main chain of PE using an extruder at $200{\sim}210^{\circ}C$, followed by exposure to three different silane crosslinking conditions (1. immersed in $80^{\circ}C$ water, 2. at $80^{\circ}C$ air forced convection oven, 3. exposed to air at room temperature ). The thermal characteristic changes of PE resins with respect to the silane crosslinking conditions were studied by measuring the crystalline melting temperature, density and crosslinking reaction rate. Because silane crosslinking was carried out at solid state, crystalline melting temperature, crystallinity, crystal growth rate, crosslinking reaction rate and the change in the density of silane crosslinked PE were affected by crosslinking condition and the type of base resin. The properties of silane crosslinked PE were different from those of Peroxide crosslinked PE which was crosslinked at the molten state. It was found, from the result of DSC analysis, that silane crosslinked linear low density polyethylene(LLDPE) crosslinked at room temperature had no secondary melting peak because the crosslinking reaction proceeds slowly as the crystalline grows. After crystallization, the melting point of PE was lowered by crystalline interruption of crosslinked site.

• Journal of Mushroom
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• v.16 no.3
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• pp.162-170
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• 2018

To improve the productivity of Pleurotus ostreatus, different conditions of liquid spawn culture were tested. The optimum culture conditions were potato dextrose broth, incubation temperature of $22^{\circ}C$, and pH 6. Fifteen different media ('A' to 'O') containing 0.3% soybean meal (SM) were prepared by varying sugar and glucose contents. The cultures were propagated in SM media for 14 days, at $22^{\circ}C$, and pH 6. Their absorbances were higher after 14 days of incubation in the media containing both sugar and glucose. In particular, the absorbance of media containing 5 to 20% of glucose alone ('C', 'D', 'E', and 'F') tended to increase in the incubation period. Dry cell weight was lower in media containing less than 20% sugar or glucose alone than in media containing 30% sugar ('A') or 30% glucose ('B') alone. In sawdust media, in 900 mL-bottle, the optimum inoculation volume of liquid spawn was 15 to 20 mL. The texture of the mushroom cultivated with the liquid spawn was superior to that cultivated in the solid spawn.

• Journal of the Korean association of regional geographers
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• v.3 no.1
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• pp.155-163
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• 1997

The Mongolian ger is ideally suited to the mongol's steppe climate and the nomadic way of life. This is a multipurpose dwelling which can be easily collapsed, transported to another place and put up again fully preserving its original shape. The pastoral nomadic ger has two key components: the wooden framework and the felt cover. The wooden parts are the walls(khana), the long poles(un), the smoke escape(toono) and its supports(bagana). One wall consists of 10-15 branches of willow tree. each about 1.5m high bound together in a way making it possible to fold it for transportation and then unfold it like an accordion. The unfolded walls are connected to form a circle. The long poles(un) are fastened to the upper part of the walls, with the other end passed through the toono hole, the only sky window and smoke escape through it from the ger. The toono is propped up by two posts, called bagana. All this forms the wooden framework of the ger, which is covered with felt. When the herders fire up their metal stoves, the temperature inside the ger becomes quite comfortable. Because the nomads live in a climate where there is only one growing season in a year, they do not make long migrations to new pastures. Livestock subsist on standing vegetation for eight months of the year. The basic pasture migration strategy is to leave enough standing vegetation at the end of the growing season in September to suffice until the new growth appears the following May. Mongolians use a type of compressed tea leaf that is called "brick" tea in English because it is rock solid and roughly the shape of a brick. And they consume a larger percent(88%) of fat from animal products such as meat, milk, butter, and cheese than any other people in the world. Milk products made from the milk of sheep, yak, and goats are major foods in the nomad's diet, but they are produced mainly in summer when all the animals are lactating. Mongolians made their special nomadic food culture on the steppe.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.1
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• pp.46-51
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• 2006

Phosphorus accumulation in fertilized soils becomes serious problem for agriculture and the environment. In this investigation, we conducted a laboratory scale investigation to find the most desirable displacement methods of the adsorbed phosphate onto the soil particle surfaces. Soil samples which contained high amount of phosphate were collected at two different depths (0-10 cm and 10-20 cm) from four locations at the moderate highland located in Nonsan, Chungnam. To observe the mobilization of solid-phase phosphate, soil samples were equilibrated with oxalic acid solutions ranging from $10^{-5}$ to $10^{-1}cmol\;L^{-1}$ with the dilution factors of 1:1, 1:2.5, 1:5, 1:10, and 1:20. The mineralized P sharply increased as the concentration of oxalic acid was greater than $5{\times}10^{-4}cmol\;L^{-1}$ under dilution factors of 1:1, 1:2.5, and 1:5. The breaking concentration of oxalic acid was lowered to $10^{-4}cmol\;L^{-1}$ and $5{\times}10^{-5}cmol\;L^{-1}$ for dilution factors of 1:10 and 1:20, respectively. The curve fit obtained from the graph can be described by exponential growth when the dilution factors were 1:1, 1:2.5, and 1:5 while the sigmoidal shape for 1:10 and 1:20, showing the mineralization of P were significantly dependent on the dilution factor.

• Korean Journal of Plant Tissue Culture
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• v.25 no.1
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• pp.1-5
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• 1998

This study describes the effect of the growth regulators such as 2,L-D and BA, on the structural abnormalities of somatic embryos derived from leaf explants of Angelica gigas Nakai, Also, the relationship between the cotyledon number of a somatic embryo and its germinability is explored. Embryogenic calli were selected from calli formed on explants cultured on MS solid basal medium supplemented with 0.5mg/L 2,4-D, 1mg/L 2,4-D, 1mg/L plus 0.1mg/L BA, and 1 mg/L 2,4-D plus 0.5mg/L BA. Cotyledonary abnormalities were observed in somatic embryos which were developed from embryogenic calli cultured on MS medium containing 1mg/L 2,4-D for 8 weeks and then subcultured on 2,4-D free MS medium for 3 weeks. The frequency of abnormalities was as follows: 22.8% one cotyledon, 42.5% two cotyledons, 16.8% three cotyledons, 7.8% four cotyledons, 1.8% five cotyledons, and 8.2% jar shaped cotyledon. In addition, ABA treatment indicated an improvement of the somatic embryo with normal cotyledon (65.3%). ABA was important role to the high production of normal somatic embryos. Two cotyledon embryos showed germinability 77.8%. However the germinability of somatic embryos with anomalous cotyledons was prominently low: One cotyledon, 62.5%; three cotyledons, 43.3%; four cotyledons, 60%; five cotyledons, 50% and jar shaped cotyledon, zero%. Thus, germinability was essentially, inversely proportional to cotyledon number.