• Korean Journal of Construction Engineering and Management
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• v.8 no.3
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• pp.134-141
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• 2007

It is crucial that the WRMSD is realized as a critical job-related diseases for the construction workers. It is caused by the characteristics of repetitive work, uncomfortable work methods and continuous unsuitable physical posture. The objective of this research is to evaluate the workload for the carpenters and structural steel workers. Investigation on the posture and behavior for the workers as well as personal sensitivity to the workload is conducted. The laboratory tests with graduate students are conducted to estimate inconvenience in terms of personal sensitivity to the workload. The results of this research will be used to perform the further researches on ergonomic and technological approaches to improvements of the hand-intensive tasks in the construction industry.

• Journal of the Korean Magnetics Society
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• v.8 no.3
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• pp.161-168
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• 1998

In this paper, a algorithm is proposed, which is applicable to the transient analysis of diffusion equations by combined use of the Laplace transform and the finite element method. The proposed method removes the time terms using the Laplace transform and then solves the associated equation with the finite element method. The solution which is solved at frequency domain is transformed into time domain by use of the Laplace inversion. To verify the proposed algorithm, a heat conduction problem is analysed. And the solution showed a good agreement with analytic solution. Because the time-step method is not needed, the proposed method is very useful in solving various kinds of diffusion equations.

• YAKHAK HOEJI
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• v.47 no.2
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• pp.110-119
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• 2003

The purpose of the present study was to kinetically investigate the carrier-mediated uptake in the hepatic transport of organic anions, and to simulate the ″in vivo counter-transport″ phenomena, using kinetic model which was developed in this study. The condition that the mobility of carrier-ligand complex is greater than that of free carrier is not essential for the occurrence of ″counter-transport″ phenomenon. To examine the inhibitory effects on the initial uptake of a ligand by the liver, it is necessary to judge whether the true counter-transport mechanism (trans-stimulation) is working or not. The initial plasma disappearance curves of a organic anion were then kinetically analyzed based on a flow model, in which the ligand is eliminated only from the peripheral compartment (liver compartment). Moreover, ″in vive counter-transport″ phenomena were simulated based on the perfusion model which incorporated the carrier-mediated transport and the saturable intracellular binding. The ″in vivo counter-transport″ phenomena in the hepatic transport of a organic anion were well demonstrated by incorporating the carrier-mediated process. However, the ″in vivo counter-transport″ phenomena may be also explained by the enhancement of back diffusion due to the displacement of intracellular binding. In conclusion, one should be more cautious in interpreting data obtained from so-called ″in vivo counter-transport″ experiments.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1428-1437
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• 1988

An analysis of radiative heat transfer has been conducted on axisymmetric finite cylindrical media. It is assumed that the temperature in the media is uniformly distributed and the boundaries are diffusely emitting and reflecting at a constant temperature. The scattering phase function is represented by the delta-Eddington approximation to account for highly forward scattering by particulates just as in the combustion system. Exact numerical solutions are obtained by Gaussian quadrature method and compared with P-1 and P-3 approximation solutions to verify their engineering application limit. The effects of optical thickness, scattering albedo, wall emissivity and aspect ratio are investigated. The results show that P-3 approximation is found to be in good agreement with the exact solution.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.1
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• pp.7-11
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• 2006

Through SCM modeling, we found that the depletion layer in silicon was of a form of a spherical capacitor with the SCM tip biased. Two-dimensional (2D) finite differential method code with a successive over relaxation (SOR) solver has been developed to model the measurements by SCM of a semiconductor wafer that contains an ion-implanted impurity region. Then, we theoretically analyzed the spherical capacitor and determined the total depleted-volume charge Q, capacitance C, and the rate of capacitance change with bias dC/dV. It is very important to observe the depleted carriers' movement in the silicon layer by applying the bias to the tip. So, we calculated the depleted-volume charge, considering different factors such as tip size, oxide thickness, and applied bias (dc+ac), which have an influence on potential and depletion charges.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1027-1032
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• 2013

LED is standing in the limelight as a light part of the low-carbon green energy. While LEDs are eco-friendly, efficient and durable, extreme heat rises can cause their durability to decrease, with 80% of the power supply being turned into heat energy. Heat radiation systems are important because rising temperatures affect the lifetime of LED elements. Therefore, in this paper, thermal analysis was performed for the shape of heat sink to the LED bulb. Also, it is applied the temperature control systems to our products for optimal performance.

• Journal of the Korean Society for Railway
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• v.11 no.6
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• pp.581-587
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• 2008

This paper presents a railway network design problem (RNDP), which can be formulated as a bi-level program. In bi-level program upper level program is to minimize total travel cost including the construction cost of the railway facilities, whilst lower one describes the railway route choice behavior of passengers. We also propose a heuristic method for solving the program because it is a kind of NP-hard problem. From two numerical railway examples, we confirm that the RNDP and its algorithm produce a reasonable solution and that it is applicable to real world.

• Korean Journal of Environmental Biology
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• v.21 no.3
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• pp.234-239
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• 2003

3-weeks old Commelina was transferred to and grown in Hoagland solution (($\pm 100 \mu M \;Cd^{2+}, 100 \mu M \;Cd^{2+}+10 \mu M\;IAA,100 \mu M\; Cd^{2+}+100 \mu M \; IAA,100 \mu M \; Cd^{2+} +1 \mu M \; IAA)$) for three weeks and then a number of physiological activities was investigated. In the control the length of stem was increased to 7 cm after 3 weeks, but in the treatment of $Cd^{2+}$, 2.0 cm was grown. In cases of IAA with $Cd^{2+}$, the growth of the plants was increased to 3.7 cm, 5.0 cm and 3.3 cm in 100 $\mu$M, 10 $\mu$M and 1 mM IAA respectively, Cadmium stimulated stomatal opening. The stomata, treated with $Cd^{2+}$ opened to n degree of about 6.1 $\mu\textrm{m}$, but the stomata, treated with no cadmium opened to 4.5 $\mu\textrm{m}$. In the treatment of various concentation of IAA with cadmium the stomata opend to about 1 $\mu\textrm{m}$ more than that of cadmium alone. Cadmium reduced total chlorophyll content up to 13% for 3 weeks. In the treatment of $Cd^{2+}$ ＋ IAA (10 $\mu$M and 100 $\mu$M) the clear change of total chlorophyll content was not observed, but in the addition of 1 mM IAA to $Cd^{2+}$ reduced the total chlorophyll content to about 9%. $Cd^{2+}$ reduced to 9% and 11% of Fv/Fm after two and three weeks respectively. In cases of IAA with $Cd^{2+}$, there were no clear changes of Fv/Fm. Cadmium reduced water potential to 67% after 3 weeks incubation, but in cases of IAA with $Cd^{2+}$, water potential was not clearly changed. Therefore, it could be concluded that the treatment of IAA showed clear alleviation of $Cd^{2+}$-induced several physiological toxicities.

• Korean Journal of Poultry Science
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• v.39 no.1
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• pp.63-70
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• 2012

This study was conducted to determine the possible use of Red Ginseng marc as stress inhibiter in thermal stress (temperature humidity index 86) and lipopolysaccharide (LPS) - exposed laying hens by investigating their effects on laying performance, blood biochemical parameters, immunoglobulin concentration and serum superoxide dismutase (SOD) like ability. A total of forty-five 52-wk-old laying hens (ISA Brown) were divided into 3 treatment groups with 5 replicates of 3 birds in each group. NC (negative control, no immune substances), PC (positive control, ${\beta}$-glucan 25 ppm) and RGM (Red Ginseng Marc 3%) were added in feed with respective substance. Egg production in RGM was significantly increased in comparison with NC groups for 8 weeks (P<0.05). On blood biochemical parameters, effects of ambient temperature is definite by showing significant difference in aspartate aminotransferase and others (P<0.05), but RGM both before and after thermal stimulation have no significant difference in comparison with other groups. And for 3 weeks after thermal stimulation, laying performance was also not significantly different among treatments. Immunoglobulin M content and SOD like activities after challenge with LPS were higher in the RGM and PC than NC (P<0.05). In conclusion, although ineffective as inhibiter in thermal stress, dietary supplementation of Red Ginseng marc improved SOD like activity and immune system by regulating immunoglobulin content in laying hens. These findings have laid the foundation for future studies of immunomodulation in laying hens fed Red Ginseng Marc and of evaluation of heat stress inhibitor.

• Korean Journal of Poultry Science
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• v.38 no.2
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• pp.137-144
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• 2011

The current work was carried out to investigate the effect of crossbred Korean native chickens (KNC) on fatty acid, amino acid and nucleotide-related compounds contents of chicken meat. A total of 360 male chicks (1d of age) was used in this work and were divided 4 groups as A) (KNC egg-meat type C strains ${\times}$ KNC meat type S strains) ${\times}$ Ross broiler, B) (KNC egg-meat type C strains ${\times}$ KNC meat type H strains) ${\times}$ KNC meat type S strains, C) (KNC native R strains ${\times}$ KNC meat type S strains) ${\times}$ KNC meat type H strains and D(White Semibroiler Chickens) strains for 5 weeks at the flat house. Palmitic acid and vaccenic acid were highest in C strain meat, and myristic acid and linolenic acid were lowest in A strain meat (p<0.05). Saturated fatty acid was lowest in C strain meats (p<0.05). Valine, leucine, phenylalanine and lysine of essential acid were low in A strain meat. Cystine, aspartic acid, glycine, alanine and proline were also low in A strain meat. Hypoxanthin (Hx) was high compared other strains at 5 weeks and low at 10 weeks. IMP was high compared other strains at 5 and 10 weeks. AMP has not significant difference among strains at 5 weeks but B strain was high other strains at 10 weeks. These results showed that C stain was excellent on the fact of nutrients compared to other strains. Consequently, the result of this work gave the basic data that needed to develope the new strains.