• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.3
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• pp.598-607
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• 1992

The environment degradation of structural steel under high temperature is one of the key phenomena governing the availability and life of plant. This degradation resulted from the microstructural changes due to the long exposure at high temperature affect the mechanical properties such as creep strength and toughness. For instance, boiler tube materials usually tend to degrade, after long term operation, by precipitates, spherodizing, coarsening, and change in chemical composition of carbides. In this study, the material degradation under high temperature exposure was investigated by evaluating the carbide precipitation. The electrochemical polarization method was facilitated to investigate the precipitation and coarsening of carbides. It was shown by the modified electrochemical potentiokinetic reactivation (EPR) tests that the passivation of Mo-rich carbides did not occur even in the anodic peak current (Ip) which indicates the precipitation of Mo$_{6}$C was also observed. And it was assured that special electrolytic cell assembled in this research can be used for the detection of Mo$_{6}$C precipitation in the field.eld.

• Journal of Information Technology Services
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• v.2 no.1
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• pp.51-73
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• 2003

The success of 2002 Korea Japan Worldcup became a good opportunity to give the message of revival to the people of Korea. With the effect of it, the national brand image has risen. Nevertheless, in order to maximize the chance of time, the most necessary thing that need to be done is to find the strategic counterproposal of the Post Worldcup. Especially, to find the more active plan in the respect of economy. In this research, we have studied the IT industry(especially SI industry) of the economy in order to look into the strategic counterproposal to get the development effect after the Worldcup. We mainly analyzed the SI industry in the respect of economy, because it is not only a high-value added industry of the integration of knowledge and technology but also a high-tech industry which has a spreading effect on the related industries. To implement the analysis of SI industry, derive and verify the strategy, and get the activating plan, we studied with 4 stages. Firstly, analyze the exterior environment and the interior strength with the Competitive Strategy Model(Specially, 7 Force Model & Value Chain Model). Secondly, get the strategy with SWOT analysis. Thirdly, verify the Strategy with interview and survey. Fourthly, classify the SI industry activation plan into 5 kinds after Worldcup through panel discussion and seminar with the data which we got through interview and survey.

• Journal of agriculture & life science
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• v.45 no.1
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• pp.33-40
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• 2011

An efficient method for the rapid micropropagation of Camptotheca acuminata from axillary buds was established by application of various plant growth regulators. Among various cytokinins, $0.5mg\;L^{-1}$ BA showed the best performance on shoot multiplication, number average multiple shoots up to 10.8. The propagated shoot cuttings in vitro were elongated on NN basal medium without plant growth regulators. The secondary multiple shoots were induced at the site of initially induced buds. Rooting was induced directly near the base of the shoot on half-strength NN medium containing $0.5mg\;L^{-1}$ of IBA, whereas high concentration of $1.0mgL^{-1}$ IBA could induce callus at the base of the shoot. The camptothecin content, anticancer compound of the micropropagated plants was contained in various tissues. Camptothecin contents were 1.8 and $2.5mg\;g^{-1}$ dry weight in stems from propagated in vitro and mother plant, respectively. This result may be used to develop strategies for large-scale propagation of elite C. acuminata trees.

• Journal of Convergence for Information Technology
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• v.9 no.11
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• pp.254-258
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• 2019

To protect healthy and beautiful hair, the hair protection effect was tested by adding an aloe extract from the hair solution. The treatment groups were grouped into four categories: Group II (Famma Treatment Only), Group III (Oxidase+aloe), Group IV (Reduce+aloe), and Group V (Oxidase+aloe, Release+aloe). The test hair is collected from women's hair in their 20s, 30s and 40s who have not undergone chemical treatment such as permanent and dying for one year and use 100% aloe stock solution. In order to evaluate hair thickness, cuticles, tensile strength, elongation and formation rate, the experiment environment was 28.9 degrees and 72% humidity. All statistical tests were done at 5% significant level. Cuticle, elongation, and formation rate were significantly improved (P<.05) and cuticle was best in group V, elongation was group III. In conclusion, aloe added to perm treatment were effective in improving cuticle, elongation rate, and formation of hair.

• Journal of Adhesion and Interface
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• v.8 no.4
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• pp.1-7
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• 2007

Waterborne polyurethane (WPU) which is environment friendly has been rapidly used in coating and adhesive industries. However, the WPU is deficient in chemical resistance, thermal resistance, and mechanical property compared to solvent-based polyurethane. In this study, the WPU was synthesized from two types of polyester polyols, 4,4-dicyclohexylmethane diisocyanate ($H_{12}MDI$), dimethylolpropionic acid (DMPA), triethylamine (TEA) and ethylenediamine (EDA), organophilic nanoclay. The thermal stability, mechanical property of the WPU nanocomposite dispersion increased with increasing clay concentration. Especially, their peel strength showed their maximum value at 3 wt% of organophilic nanoclay contents.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.179-186
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• 2008

In proportion as the growth of the wireless sensor network applications, we need for more accuracy wireless channel information. In the case of indoor or outdoor wireless sensor networks, multipath propagation causes severe problems in terms of fading. Therefore, a path-loss model for multipath environment is required to optimize communication systems. This paper deals with log-normal path loss modeling of the indoor 2.4 GHz channel. We measured variation of the received signal strength between the sender and receiver of which separation was increased from 1 to 30m. The path-loss exponent and the standard deviation of wireless channel were determined by fitting of the measured data. By using the PRR(Packet Reception Rate) of this model. Wireless sensor channel is defined CR(Connect Region), DR(Disconnected Region). In order to verify the characteristics of wireless channel, we performed simulations and experiments. We demonstrated that connection ranges are 24m in indoor, and 14m in outdoor.

• Journal of the Korea Society of Computer and Information
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• v.26 no.10
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• pp.45-51
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• 2021

In this paper, we propose a 3D design method of the vacuum forming method of the front part to improve the lightness and production efficiency of agricultural electric vehicles. For agricultural electric vehicles, lightness and production efficiency are more important than the strength of materials for collision protection. In this paper, we propose a vacuum forming design method that can replace complex machining processes such as laser machining, bending, and painting. The main purpose of this research is to improve product stability, productivity and convenience through 3D design of the front part and development of vacuum forming mold technology. Research procedure follows the 3D modeling of the front part using CATIA, finite element analysis for the structural stability using ABAQUS, manufacturing prototype for the investigation of the dimensions using 3D scanner and actual driving test under agricultural electric vehicle usage environment. The results verifies the proposed 3D design method of the vacuum forming method and are expected to be widely used by agricultural workers through the simplification of the production process of agricultural electric vehicles.

• Animal Bioscience
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• v.34 no.11
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• pp.1802-1810
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• 2021

Objective: The purpose of this study was to evaluate the effects of supplementing herbal active ingredients (YGF251) which can promote the secretion of insulin-like growth factor-1 (IGF-1) in the diet on production performance, egg quality, blood hematology, and excreta gas emission in laying hens. Methods: A total of 288 ISA Brown (41-week-old) laying hens with an initial body weight of 1.83±0.68 kg were randomly assigned to 1 of 4 dietary treatments in a randomized block design based on body weight. Each treatment had 12 replicate cages having 6 adjacent cages per replicate (hens are kept in cages alone). The experimental period was 35 days. Dietary treatments were based on the corn-soybean meal-wheat-based basal diet and supplemented with 0.00%, 0.05%, 0.10%, or 0.15% YGF251. Results: There was a linear increased egg weight in weeks 1 to 5 (p<0.05), egg mass in week 1 (p<0.05) and weeks 1 to 5 (p<0.05), egg strength on day 7 (p<0.05), 21 (p<0.01), and 35 (p<0.01), eggshell thickness on day 21 (p<0.05) and 35 (p<0.01), haugh unit on day 21 (p<0.01) and 35 (p<0.05), serum IGF-1 concentration on day 21 (p<0.05) and 35 (p<0.01), and serum total protein concentration on day 35 (p<0.05) were observed with the supplementing YGF251 increased in the diet, while feed conversion ratio in weeks 1 to 5 (p<0.05) and excreta ammonia emission (p<0.01) decreased linearly with the dose of YGF251 increased. Conclusion: Dietary supplementation of YGF251 positively affected the production performance and egg quality of laying hens through increasing serum IGF-1 concentration in a dose-dependent manner. Moreover, YGF251 supplementation improved barn environment by reducing excreta noxious gas emission.

• Physical Therapy Rehabilitation Science
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• v.9 no.4
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• pp.302-308
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• 2020

Objective: The endurance and strength of deep neck flexor (DNF) muscles have a major role on the function and stability of the cervical spine. In recent years, there has been a lack of research that have investigated the muscle tone of the superficial neck muscles. The purpose of this study was to examine the relationship of between contraction ratio of the DNF and sternocleidomastoid (SCM) muscles, DNF endurance, and muscle tension of the neck muscles. Design: Cross-sectional study. Methods: Forty-seven subjects (male=20, female=27) participated in this study. The muscle tone of the upper trapezius (UT), SCM, and suboccipital (SO) muscle was measured using a contact soft tissue tone-measuring instrument. For the contraction ratio of the SCM and longus colli muscle, the thickness of the relaxation and maximum contraction state of the SCM and longus colli muscles were assessed using a diagnostic ultrasound measuring instrument and a pressure biofeedback unit. The deep neck flexor endurance test (DNFET) was performed in a cranio-cervical flexion posture. The correlations between the measured variables were investigated. Results: The relationship between the DNFET and SO tone showed a significant negative correlation (p<0.05). The relationship between the DNFET and contraction ratio showed a significant positive correlation (p<0.01). There was no significant correlation between the DNFET and SCM and UT tone. Conclusions: This study confirmed that there is a relationship between DNF endurance, DNF activation, and SO tone. The information on the results of this study may be used as a reference that can be actively applied in the clinical environment.

• Journal of Korea Water Resources Association
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• v.52 no.2
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• pp.115-123
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• 2019

The effects of the Froude numbers on turbulent flow patterns downstream of a non-submerged spur dike were investigated in a laboratory flume. Three-dimensional velocities and water depths were measured using Acoustic Doppler Velocimetry and distance sensors under three Froude number conditions ($Fr_d=0.31$, 0.38, and 0.46). The results show that there are marginal differences in the velocity fields downstream of a spur dike due to the change of the Froude number. However, an increase of the Froude number was found to reduce cross-sectional area in the flow and to increase the strength of the jet-like flow. The jet-like flow was observed to displace the location of the maximum turbulence kinetic energy within a cross section toward the inner bank in the transverse direction.