• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.628-634
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• 2016

We investigated the characteristics and rate of development of allotriploid embryos derived from a cross between female olive flounder Paralichthys olivaceus and male starry flounder Platichthys stellatus. The allotriploidy was induced by cold shocking fertilized eggs three minutes post-fertilization at 3°C for 45 minutes. The average cellular DNA content of the allotriploid embryos was 2.06±0.03 pg/cell, which is equal to the sum of the cellular DNA content of a diploid olive flounder (1.42 pg/cell) and a haploid starry flounder (0.66 pg/haploid cell). The first cleavage, midblastula, gastrula and Kupffer's vesicle appearance stages of the allotriploid eggs began at 1.5, 8, 13 and 26 hours after cold shocking at 18°C, respectively. The developmental rate of allotriploid eggs was equivalent to that of diploid and triploid olive flounder eggs at 10, 14 and 18°C. However, the hatching times of allotriploid eggs, 7 h at 10°C, 5 h at 14°C and 4 h at 18°C, were earlier than those of diploid and triploid olive flounder.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.5
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• pp.620-632
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• 2017

A chemical vapor curing method(CVC) was developed to cure polycarbosilane(PCS) fibers by using cyclohexene vapour as a non-oxygen active reactant, instead of air in oder to prepare the silicon carbide(SiC) fiber with low oxygen content. A cross-linked PCS fibers by cyclohexene vapor showed a completely different variation in IR spectra in comparison to the air-cured PCS fiber. CVC method resulted in less than 3 wt% in oxygen content. In this experiment conditions, The average tensile strength and modulus of SiC fiber obtained by CVC had 1995 MPa and 183 GPa respectively, which is higher than that of SiC fiber prepared by air-curing process.

• Journal of the Korean Magnetics Society
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• v.27 no.4
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• pp.129-134
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• 2017

Bulk-type body-centered-tetragonal Fe-Co alloy was synthesised by utilising a conventional alloy preparation technologies, such as melting, solidification, and homogenising treatments, and its magnetic properties were investigated. In the $(Fe_{100-x}Co_x)_{1-y}C_y$ alloy, the composition range, from which single phase body-centered-tetragonal alloy (martensite phase) was obtained, was severely limited: Co content x = 2.5, and C content y = 0.062. Tetragonality(c/a) of the synthesised body-centered-tetragonal $(Fe_{97.5}Co_{2.5})_{0.938}C_{0.062}$ alloy was 1.05. Magnetocrystalline anisotropy constant ($K_1$) of the body-centered-tetragonal $(Fe_{97.5}Co_{2.5})_{0.938}C_{0.062}$ alloy was measured to be $9.8{\times}10^5J/m^3$), which was 3.1 time as high as the pure iron (${\alpha}-Fe$).

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.4
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• pp.3931-3942
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• 1975

This study was conducted to investigate the strength of soil cement for varied curing temperatures (0,10,20,30,40,50,60$^{\circ}C$) and cement content (3,6,9,12%) in four cement-stabilized soils (KY: sand, MH: sand, SS: sandy loam, JJ:loam). The experimental results obtained from unconfined compressive strength tests were as follows: 1. According to increase of curing temperature as 30,40,50, and 60$^{\circ}C$, the unconfiened compressive strength of soil cement increased, the rate of increase in the early curing period was large, and around 120 hours was suifficient curing time to complete hardening. 2. The strength at 10$^{\circ}C$ decreased to the rate of 30 to 40 percent than that of 20$^{\circ}C$ while the strength at 0$^{\circ}C$ was very small, strength of soil cement increased in cold weather unless that the temperature was below 0$^{\circ}C$ 3. The average maximum temperature, about 30$^{\circ}C$ during July and August in Korea may be recommended for a optimum construction period to increase the strength of soil cement. 4. Accelerated curing time that strength was equivalent to 28-Day norma1 curing decreased in accordance with the increase of curing temperature, and also accelerated curing decreased the effect of cement content. Accelerated curing that strength was equivalent to 28-day normal curing for soil cement of cement content 9% and temperature 60$^{\circ}C$ was 45 hours; KY, 50 hours: MH, 40 hours; SS, 34 hours; JJ. 5. According to the increase of the percent passing of No. 200 sieve, accelerated curing times became shorter to become the required stength. 6. Relation between accelerated curing times and normal curing days was showeda linear of which slope decreased in accordance with the increase of curing temperature, it may be expressed as follows: (1). 30$^{\circ}C$ t=3.6d+6(r=0.97) (2). 40$^{\circ}C$ t=3.2d-5.1(r=0.95) (3). 50$^{\circ}C$ t=2.1d-4.0(r=0.93) (4). 60$^{\circ}C$ t=1.4d+4.0(r=0.90) in which t=accelerate curing time. d=normal curing day. 7. Accelerated curing time that the strength was equivalent to 35kg/$\textrm{cm}^2$ which was the strength of cement brick was 96 hours at temperature 30$^{\circ}C$ to SS 9%, and 120 hours at temperature 50$^{\circ}C$ to JJ 9%, Consequently, a economic soil cement brick may be made in future.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.1
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• pp.39-45
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• 2003

The varistor properties of ZnO-Pr$_{6}$O$_{11}$-CoO-based ceramics doped with Sm$_2$O$_3$were investigated in the addition range of 0.0~2.0 mol% Sm$_2$O$_3$at sintering temperature of 130$0^{\circ}C$ and 135$0^{\circ}C$. As Sm$_2$O$_3$ content is increased, the breakdown voltage was increased in the range of 348.9~521.8 V/mm for ceramics sintered at 130$0^{\circ}C$ and 8.5~381.3 V/mm for ceramics sintered at 135$0^{\circ}C$. On the whole, the increase of sintering temperature led to the low nonlinearity regardless of Sm$_2$O$_3$content. ZnO-Pr$_{6}$O$_{11}$-CoO-based ceramics doped with 1.0 mol% at each sintering temperature exhibited the most superior varistor properties, with the nonlinear exponent of 42.1 at 130$0^{\circ}C$, 36.8 at 135$0^{\circ}C$ and the leakage current of 9.2 $\mu$A at 130$0^{\circ}C$, 11.7 $\mu$A at 135$0^{\circ}C$.EX>.EX>.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.77-82
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• 2003

The purpose of this study is development of technique to use cementitious powder as recycle cement produced from deteriorated Concrete waste which has a large quantity of calcium carbonate. Therefore, after having theoretical consideration based on the properties of hish-heated concrete and concerning about neutralization of Concrete, we analysis chemical properties of ingredients of cementitious powder After making origin cement paste, then processing the accelerated carbonation, we consider the properties of hydration and chemical properties of cementitious powder under various temperature conditions As a result of the thermal analysis, the CacO3 content of cementitious powder would affect decision of heat temperature to recover its hydrated ability because CacO3 content is increased when neutraliTation is preBlessed. And as a result of XRD analysis. in case of origin powder of non-neutralized paste, CaO peak is found at $700^{\circ}C$. but, heat temperature to generate CaO would increase when the content of neutralized ingredients is increased. Finally, recycle cement heated at $700^{\circ}C$ shows the best compressive strength when the content of neutralized ingredients in recycle cement is less then 50%. However, it would be quite difficult to manage quality of recycle cement according to recycling points of various concrete waste.

• Journal of Preventive Medicine and Public Health
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• v.21 no.1 s.23
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• pp.121-131
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• 1988

This study was performed to investigate the heavy metal contents of freshwater fishes. The samples of 24 species were collected at 7 areas located on the Mankyung River during September in 1987. And then the contents of lead, cadmium, copper and zine were analyzed by atomic absorption spectrophotometer. The results were summarized as follows ; 1. The mean value of lead, cadmium, and copper contents of fishes collected in the downstream were significantly higher than those of upstream. 2. The mean lead content of C. auratus was the highest $1.50{\pm}0.98{\mu}g/g$ in viscera and statistically significant difference from muscle content. 3. The mean cadmium content of C. auratus was the highest $0.087{\pm}0.054{\mu}g/g$ in viscera and significantly higher than that of muscle. 4. In the copper contents, the viscera of C. auratus was the highest $5.25{\pm}0.94{\mu}g/g$ and significantly higher than that of muscle, skeleton and gill. 5. The mean value of zinc content of C. auratus was shown the order of gill, skeleton, viscera and muscle.

• Journal of the Korean Society of Food Culture
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• v.13 no.1
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• pp.9-17
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• 1998

The objective of this study is to provide a fundamental data to improve meals of the college foodservice operations serving more than 300 meals per day through evaluating changes in; total vitamin C contests, water contents, and pH, in the process of handling such foods as soybean sprout cooked and of fresh vegetable salads. This study, also, tried to identify nutrition reduction, step by step, to minimize nutrition loss. 1. In handing COOKED SOYBEAN SPROUTS, total vitamin C contents were higher after wash(1.54%mg%) than other cooking methods adopted in university meals(1.08mg%), however, total vitamin C contents was significantly lost during boiling step. 2. Significant loss of total vitamin C and water content in the FRESH VEGITABLE SALADS was detected in the process of washing and cutting vegitables. Especially,'cabbage' lost 20% of total vitamin C in the process of 'soaking in water', which was one of preparation process 3. Significant loss of vitamin C was observed after 6 hours of HOLDINC AFTER COOKING but it can be reduced through holding under lower temparature, in case of soybean sprouts and fresh vegitable salads. pH became acidic as holding time expanded. WATER CONTENT of cooked soybean sprouts decreased up to 4 hours holding time, however, it increased when we checked at after 6 hours' of holding time. Water content continuously decreased up to 6 hours of holding time in case of FRESH VESITABLE SALADS with the statistically significance level.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1940-1946
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• 2006

The influence of environmental conditions on the ganoderic acid (GA) content in the fungus Ganoderma lucidum was investigated using a one-factor-at-a-time design and orthogonal design. Among the various medium components examined, sucrose, soybean powder or peptone, ferrous sulfate, and pH 6.0 were the most suitable carbon source (factor A), nitrogen source (factor B), mineral source (factor C), and initial pH (factor D), respectively, for the GA content in the one-factor-at-a-time design. According to the orthogonal design, the order of effect for the four factors on the GA content was A>C>D>B. The best level of factor A was $A_2$ (sucrose) with a value of +0.34 mg/100 mg DW. The optimal treatment combination was $A_2B_1C_3D_1$ with which the GA content reached up to 2.63$\pm$0.011 mg/100 mg DW. The interactions between the mineral ion and the nitrogen source, and the mineral ion and the pH were both highly significant (P<0.01). The highest interaction effect was ($B_2{\times}D_2$) with a value of +0.19 mg/100 mg DW, which was higher than the level effect value for $B_2$ (peptone) and D$_2$ (pH 5.0). Therefore, the results proved that interactions between factors cannot be ignored. The results also indicated the importance of the interactions between the factors, which may help to understand the metabolic pathway leading to triterpene biosynthesis and the expression and regulation of the key enzymes involved.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.3
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• pp.64-72
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• 2004

The research was carried out to define the environmental characteristics and vegetation structure of the evergreen fern habitat in Jejudo. The growth conditions of evergreen fern in various habitats was surveyed, including topographical features, vegetation structure, air temperature, humidity, intensity of light, water content and organic matter content in the soil. In the direction of the native habitat, 70% of research area was located in the southeast-facing slopes, 30% was located in southern slopes. The gradient ranged from $0^{\circ}$ to $30^{\circ}$. Temperature ranged from $16^{\circ}C$ to $28^{\circ}C$, and $22.3^{\circ}C$ was the average. Humidity ranged from 20 to 68%, and 36% was the average. In the native habitat, the highest light intensities reached 60,000 to 80,0001ux, but in general ranged from 300 to 40001ux. Water content in the soil ranged from 32% to 59%, organic matter content ranged from 8 to 13%. Within a unit of 25$m^2$, there were tall-tree layer such as Quercus galuca and Castanopsis cuspidata with a covering of rate 40~80%, a sub-tall-tree layer such as Camellia japonica, Staphylea bumalda and Sambucus williamsii with the covering rate of 3~5%, a shrub layer with the covering rate of 5~20%, and a grass layer with the covering rate of 40~95%. This research provides the basic data about the native habitat environment of the evergreen fern plant. Continuous monitoring and accumulation of data is necessary for the use of evergreen fern as vegetation materials.