• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.229-236
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• 2019

The effects of temperature, salinity and irradiance on the growth of dinoflagellate Alexandrium affine were examined. A maximum specific growth rate ($0.69day^{-1}$) was observed with a combination of $25^{\circ}C$ and 25 psu. Optimal growth (80 % of the maximum specific growth rate) was obtained at $20-26^{\circ}C$ with salinities of 20-35 psu. The results indicated that A. affine is relatively stenothermal of given high water temperature and is a euryhaline species. The irradiance-growth curve found can be described as ${\mu}=0.75(I-4.25)/(I+65.47)$. The compensation photon flux density ($I_c$) and half-saturation photon flux density ($K_I$) were $4.25{\mu}mol\;m^{-2}s^{-1}$ and $57.0{\mu}mol\;m^{-2}s^{-1}$, respectively. In conclusion, A. affine has advantageous physiological characteristics that enable it to be a dominant species in coastal areas with high water temperature and a large salinity gradient, in spite of relatively low irradiance.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.1
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• pp.12-16
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• 2004

In this study, we have investigated the development of the crystal growth stability and reproducibility for large and high-quality DAST. DAST crystal were grown from a saturated methanol solution by a slow cooling method and DAST was synthesized by the condensation of 4-methyl-n-methyl pyridinum tosylate, which was prepared from 4-pocoline and methyl toluenesulponate and 4-N-dimethyl amino-bezaldehyde in the presence of piperidine. We had synthesized DAST crystals in dry Argon atmosphere in order to avoid the formation of hydride organge co-crystals, DAST$.$$H_2O$. Since DAST molecules crystallize in a humid atmosphere, crystal structure become centrosymmetric, and then second order NLO (nonlinear optical) properties would be disappeared. We fixed the growth orientation of DAST crystal (001) surface. The crystal growth was proceeded at a cooling rate of $H_2O$/day and the cooling period is for 4 days. The dimensions of seed crystal was $2.5\times 3.6\times0.4\textrm{mm}^3$ and we have obtained a DAST crystal with the dimension of $10\times 10.5\times3.0\textrm{mm}^3$. The color of grown DAST crystal is red and it's surface appears to be metallic green.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.64-68
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• 2005

In recent years, there has been a growth of the manufacture and application of magnesium products because of its small specific gravity as well as its relatively high strength. However, there are so many studies to assure good formability because magnesium sheet alloy is difficult to form. In this study, uniaxial tensile and biaxial tensile test of AZ31 magnesium sheet alloy with thickness of 1.2mm were performed at room temperature. Uniaxial tensile test were performed until $7\%$ of engineering strain. R-values and stress-strain curve were obtained. Biaxial tensile tests with cruciform specimen were performed until the breakdown of the specimen occurs. The yield loci are made by application of plastic work theory. The results are compared with the theoretical predictions based on the Hill and Logan-Hosford model. However, next study will be performed at warm-temperature because the specimens are broken under the $0.5\%$ of equivalent strain at biaxial tensile test.

• Steel and Composite Structures
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• v.19 no.6
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• pp.1549-1560
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• 2015

This paper presents the characterization of fatigue crack in the A283 Grade C steel using the MMM method by identifying the effects of magnetic flux leakage towards the crack growth rate, da/dN, and crack length. The previous and current research on the relation between MMM parameters and fatigue crack effect is still unclear and requires specific analysis to validate that. This method is considered to be a passive magnetic method among other Non-Destructive Testing (NDT) methods. The tension-tension fatigue test was conducted with a testing frequency of 10 Hz with 4 kN loaded, meanwhile the MMM response signals were captured using a MMM instrument. A correlation between the crack growth rate and magnetic flux leakage produces a sigmoid shape curve with a constant values which present the gradient, m value is in the ranges of 1.4357 to 4.0506, and the y-intercept, log C in the ranges of $4{\times}10^{-7}$ to 0.0303. Moreover, a linear relation was obtained between the crack length and magnetic flux leakage which present the R-Squared values is at 0.830 to 0.978. Therefore, MMM method has their own capability to investigate and characterize the fatigue crack effects as a main source of fracture mechanism for ferrous-based materials.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.405-415
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• 2000

To determine application rate of elemental sulfur to adjust pH of alkaline soil, buffer curve method was investigated. The elemental sulfur required to control pH 8.3 to pH 6.3 by buffer curve calculation was treated in two soils of silty loam and sandy loam, and the sulfur-mixed soils were moistened with 50% of water holding capacity during incubation of 6 weeks at $30^{\circ}C$. Soil pH was lowered with incubation and reached to target point after 4 weeks of incubation, and elemental sulfur was oxidised entirely to sulfate. This means that buffer curve has the accuracy to determine sulfur application rate in alkaline soil. However it is estimated that application rate of sulfur should be carefully determined in the field scale. Excess application of elemental sulfur resulted in extremely low soil pH and caused the hinderance of lettuce growth by nutritional imbalance and ion toxicity. To simplify the determination procedure of sulfur requirement, buffer curve method by addition of 0.1N-HCl solution as unit of mL was developed, it was compared with theroutine methods which diluted $H_2SO_4$ solution and $Ca(OH)_2$ are added as cmolc per kg soil to adjust each pH step. Buffer capacities, cmolc kg $soil^{-1}$ $pH^{-1}$, calculated from two buffer curves were not significantly different. The result indicates that buffer curve method by 0.1N-HCl can be used to adjust high pH of alkaline soil.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.1
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• pp.1-10
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• 2014

The effects of temperature, salinity and irradiance on the growth of the dinoflagellate Akashiwo sanguinea isolated from Jaran Bay were examined in the laboratory. Maximum specific growth rate($0.28day^{-1}$) was observed with combination of $25^{\circ}C$ and 30 psu. Optimal growth (${\geq}80%$ of maximum specific growth rate) was obtained at $25^{\circ}C$ with salinities of 15~35 psu. This results indicated that A. sanguinea is a stenothermal of the high water temperature and euryhaline species. The irradiance-growth curve was described as ${\mu}=0.31(I-16.87)/(I+51.19)$. The compensation photon flux density ($I_0$) and half-saturation photon flux density ($K_I$) were $16.87{\mu}mol\;m^{-2}s^{-1}$ and $84.93{\mu}mol\;m^{-2}s^{-1}$, respectively. In conclustion, A. sanguinea has advantage physiological characteristics for the species succession at the coastal areas in summer with sufficient irradiance, high water temperature and large salinity gradient.

• Korean Journal of Family Social Work
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• no.53
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• pp.199-234
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• 2016

This study deals with the psycho-social development of children raised by disabled parents. In particular, we are willing to examine the influence of parental factors such as social engagement and future forecast on the change of children's psycho-social development. Using the three waves of Korean Welfare Panel Study data, these predictors were examined through the Latent Growth Curve Modeling. The result shows that parent's disability has a negative influence on their children's psycho-social development. However, similar to the findings of the previous studies, the degree of this influence tends to be decreased as children grow up. Lastly, two parental factors have a direct influence on the psychological development of children. Furthermore, parent's social engagement has an indirect influence on the change of sociality of children through the psychological change of them. This result means that we should encourage disabled parents to participate actively in social activities and think positively about their future.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.3
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• pp.234-243
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• 2000

This paper is to study population ecological characteristics, including growth parameters, survival rate, instantaneous coefficients of natural and fishing mortalities, and age at first capture of the soft-shelled clam, Mya japonioa in the intertidal zone of South Sea in Korea. For describing growth of the clam a von Bertalanffy growth model was adopted, The von Bertalanffy growth curve had an additive error structure and the growth parameters estimated from a non-linear regression were SH/sub ∞/=79.83mm, K=0.26, and t/sub 0/= -0.01. Survival rate (S) of the soft-shelled clam was 0.26 (SD=0.02). The instantaneous coefficients of natural mortality (M) was estimated to be 0.78/year and fishing mortality (F) 0.57/year for the soft-shelled clam. The age at first capture (t/sub c/) was estimated as 2.69 year. The mean densities of the soft-shelled clam by bottom type were 3.40 inds./m²(SE=0.18) in the sand, 63.4 inds./m²(SE= 0.53) in the muddy sand, and 0 inds./m2 (SE=0) in the gravelly sand. The mean densities of the soft-shelled clam by 3 different areas were 4.88 inds./m²(SE=0.09), 2.61 inds./m²(SE=0.13), 7.20 inds./m²(SE=0.18), respectively and the biomass of the clam were estimated as 131mt, 121mt, 665mt, respectively. An yield-per-recruit analysis showed that the current yield-per-recruit of about 8.30g with F=0.57/year and the age at first capture (t/sub c/) 2.69 year, was lower than the maximum possible yield-per-recruit of 9.60g. Fixing to at the current level and increased fishing intensity (F) could produce an increase in the predicted yield-per-recruit from 8.30g to about 9.40. However, estimated yield-per-recruit increased to 1.30g by decreasing to from the current age (2.69 year) to age two with F fixed at the current level. Yield-per-recruit was estimated under harvest strategies based on F/sub max/ and F/sub 0.1/.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.3
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• pp.331-335
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• 1999

The present study describes the analysis of the multiphasic growth function (MGF) to body weight in laboratory and wild mice. Three genetic groups of laboratory mice (Mus musculus domesticus) designated $CF_{{\sharp}1}$, C3H/HeNCrj and C57BL/6NCrj, and a genetic group of Yonakuni wild mice (Mus musculus molossinus yonakuni, Yk) were used. Mean body weights of each genetic group-sex subclass from birth to 69 days of age taken at 3-day intervals were analyzed by a monophasic, diphasic and triphasic functions for describing growth patterns. A comparison among the three functions of the MGF was based on the goodness-of-fit criteria: residual standard deviation (RSD), adjusted R-square (Adj $R^2$) and Akaike's information criterion (AIC). Result of this study indicated that body weight averaged heavier for males than for females. Among the four genetic groups within both sexes, $CF_{{\sharp}1}$ showed the highest, subsequent followed by C3H/HeNCrj, C57BL/6NCrj and Yk. Comparison among the three functions revealed that the triphasic function was the best fit to growth data, with the lowest RSD, the highest Adj $R^2$ and the lowest AIC, for the four genetic groups. For the triphasic function, RSD within each genetic group-sex subclass was similar for males and females. Adj $R^2$ was 0.999 for all genetic group-sex subclasses. AIC for laboratory mice males and females ranged from -70.48 to 66.50 and from -92.81 to -68.64, respectively; whereas for Yk wild mice males was -74.29 and females -78.42.

• Korean Journal of Ichthyology
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• v.23 no.1
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• pp.30-36
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• 2011

Age and growth of shotted halibut Eopsetta grigorjewi were estimated using right sagittal otoliths of 389 fish specimens from February 2004 to January 2005 in the East China Sea. Examination of outer margins of the otolith showed that the opaque zone was formed once a year and annual rings were formed from December to March. The age of specimens examined ranged from 3 to 5 years. Shotted halibut begin spawning in February and show a peak in March. Length and weight relationships showed no significant difference between females and males (P>0.05), and can be expressed as TW=$0.5091{\times}10^{-2}TL^{3,222}(r^2=0.92)$. Estimated von Bertalanffy growth curve was $L_t=46.58(1-e^{-0.14(1+1.32)})$.