• Korean Journal of Optics and Photonics
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• v.8 no.2
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• pp.134-141
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• 1997

We design the single mode dispersion-compensating fibers (DCF) which may be necessary for upgrading the previously installed 1.31 ${\mu}{\textrm}{m}$ optical communication system to the 1.55 ${\mu}{\textrm}{m}$ system. To obtain the optimum index profile that allows large negative dispersion at 1.55 ${\mu}{\textrm}{m}$, parabolic-index, double-clad fibers are analyzed by applying the 1-D FEM to the scalar wave equation of optical fibers. In constideration of macro-bending loss, the fibers are designed so that the cutoff wavelength of the $LP_{01}$ mode is greateer than 1.80 ${\mu}{\textrm}{m}$. The computer simulations show that the lower bound of the dispersion at 1.55 ${\mu}{\textrm}{m}$ is limited to about -120 ps/nm . km for the fiber index profiles satisfying the $LP_{01}$'s cutoff condition.

• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.55.2-55.2
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• 2009

• Magazine of the Korea Concrete Institute
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• v.24 no.3
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• pp.55-60
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• 2012

• Biomolecules & Therapeutics
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• v.7 no.2
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• pp.185-190
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• 1999

The current study was performed to determine the acute oral toxicity of P55A, a crude extract of 1 : 1 mixture of Phellodendron amurense cortex and Aralia elata cortex, in SD rats and beagle dogs. 5 rats of each sex were treated with a single dose of P55A orally at doses of 0 and 5,000 mg/kg respectively. Also 2 dogs of each sex were treated with a single dose of P55A orally at doses of 0 and 2,000 mgAg, respectively. After the treatment, clinical signs, and body weight change were observed for 14 days. All rats survived during the study and did not show any clinical sign. Body weight gain showed no significant difference between the control and treated rats. Grossly, no lesion was observed in the rats. All dogs survived during the study. In clinical signs, dark stool was observed in the 2,000 mg/kg treated dogs at day 1 after administration. The animals recovered from general signs at day 2 after administration. Body weight gain showed no significant difference between the control and treated dogs. Grossly, no lesion was observed in the dogs. It is suggested that the LD$_{50}$ of P55A by oral administration was estimated to be over 5,000 mg/kg in both sexes of rats and 2,000 mg/kg in both sexes of beagle dogs.s.

• Journal of the Korean Ceramic Society
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• v.55 no.2
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• pp.166-173
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• 2018

In order to investigate the effect of Mn on the dielectric and piezoelectric properties of PMN-PT [$Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$], four different types of 71PMN-29PT samples were prepared using the solid-state single crystal growth (SSCG) method: (1) Undoped single crystals, (2) undoped polycrystalline ceramics, (3) Mn-doped single crystals, and (4) Mn-doped polycrystalline ceramics. In the case of single crystals, the addition of 0.5 mol% Mn to PMN-PT decreased the dielectric constant ($K_3{^T}$), piezoelectric charge constant ($d_{33}$), and dielectric loss (tan ${\delta}$) by about 50%, but increased the coercive electric field ($E_C$) by 50% and the electromechanical quality factor ($Q_m$) by 500%, respectively. The addition of Mn to PMN-PT induced an internal bias electric field ($E_I$) and thus specimens changed from piezoelectrically soft-type to piezoelectrically hard-type. This Mn effect was more significant in single crystals than in ceramics. These results demonstrate that Mn-doped 71PMN-29PT single crystals, because they are piezoelectrically hard and simultaneously have high piezoelectric and electromechanical properties, have great potential for application in fields of SONAR transducers, high intensity focused ultrasound (HIFU), and ultrasonic motors.

• Journal of the Korean Ceramic Society
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• v.55 no.3
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• pp.290-298
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• 2018

In order to investigate the effect of thickness on the dielectric and piezoelectric properties of (001) PMN-29PT single crystals, three different types of PMN-29PT samples were prepared using the solid-state single crystal growth (SSCG) method: high density crystal [99%], low density crystal [95%], and high density crystal doped with Mn [98.5%]. When their thickness decreased from 0.5 mm to 0.05 mm, their dielectric constant ($K_3{^T}$), piezoelectric constants ($d_{33}$ and $g_{33}$), and electromechanical coupling factor ($k_t$) decreased continuously. However, their dielectric loss (tan ${\delta}$) increased. The addition of Mn to PMN-PT induced an internal bias electric field ($E_I$), increased the coercive electric field ($E_C$), and prevented local depoling. Therefore, Mn-doped PMN-PT crystals show high stability as well as high performance, even in the form of very thin plates (< 0.2 mm), and thus are suitable for application to high frequency composites, medical ultrasound probes, non-destructive testing devices (NDT), and flexible devices.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.12
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• pp.1758-1762
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• 2001

Equal number of red jungle fowl (JF) and commercial broiler chickens (CB), raised in battery cages, were provided a single complete diet (control) or a choice of a complete diet, ground corn and ground soybean from 21 to 56 days of age. There were significant genotype ${\times}$ feeding regimen interactions for several traits measured suggesting CB and JF responded differently to the two feeding regimens. The single fed CB had better growth and feed conversion ratios (FCR) than those under choice feeding. However, the body weight and FCR of JF were not affected by feeding regimen. While the single fed and choice-fed JF consumed similar amount of protein during days 21 to 55, the protein intake of the choice-fed CB was lower than the control. From days 21 to 55, irrespective of genotype, choice-fed chicks consumed less energy than their single fed counterparts. Regardless of genotype, the trend in the proportion of each feed consumed was similar with complete diet>corn>soybean. In conclusion, while choice-fed JF were capable to select nutrient necessary for maximum growth, choice feeding was detrimental to growth and feed conversion ratio in CB.

• Structural Engineering and Mechanics
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• v.55 no.5
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• pp.953-964
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• 2015

A model has been proposed that can predict the ultimate torsional strength of single-box multi-cell reinforced concrete box girder under combined loading of bending, shear and torsion. Compared with the single-cell box girder, this model takes the influence of inner webs on the distribution of shear flow into account. According to the softening truss theory and thin walled tube theory, a failure criterion is presented and a ultimate torsional strength calculating procedure is established for single-box multi-cell reinforced concrete box girder under combined actions, which considers the effect of tensile stress among the concrete cracks, Mohr stress compatibility and the softened constitutive law of concrete. In this paper the computer program is also compiled to speed up the calculation. The model has been validated by comparing the predicted and experimental members loaded under torsion combined with different ratios of bending and shear. The theoretical torsional strength was in good agreement with the experimental results.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.55-63
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• 1998

The growing conditions of barium nitrate Ba(NO3)2 single crystals by aqueous solution method have been studied. Supersaturation of Ba(NO3)2 was 0.7% at 32.0$^{\circ}C$ and about 3% 34.0$^{\circ}C$. The obtained single crystals have three kind of morphology; the tertrahedron, the cube and rarely dodecahedron face. The faces of obtained crystals have been identified by X-ray diffractometer.

• The Korean Journal of Community Living Science
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• v.14 no.1
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• pp.55-71
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• 2003

The purpose of this study was to evaluate the financial status of single mother households by financial ratios. Data was drawn from Labor Panel Survey Data in 1999, and 198 single mother households were selected. Major findings were as follows: 1) The levels of after-tax income, income per person, expenditure, expenditure per person, asset, pure asset, and debt of single mother households were lower than their counter-parts. 2) All financial ratios showed that both financial security and financial growth of single mother households were lower than their counter-parts. Especially, 22% of single mother households had the lower level of income that the lowest cost of living.