• Composites Research
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• v.26 no.1
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• pp.1-6
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• 2013

CNT-polypropylene (PP) composites were compounded by solvent dispersion method with uniform dispersion by using twin screw extruder. Damage sensing effects based on conductive carbon nanotubes (CNT) were evaluated to monitor the internal damage of CNT-PP composites using electrical resistance measurement. Mechanical and interfacial properties of CNT-PP composites were investigated and compared with neat PP. The mechanical properties of PP matrix were improved after adding CNT, because of the reinforcing effect of CNT fillers. In order to monitor the internal damage of CNT-PP composite, the change in electrical resistance of the composites was measured under fatigue loading and bending tests. CNT fillers exhibited good sensing under electrical resistance measurements. It is shown that CNT-PP composites with low CNT contents allow identifying critical cyclic loading, which are found to be accompanied with the internal failure.

• Composites Research
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• v.16 no.3
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• pp.18-24
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• 2003

Sandwich structures have been widely used in the applications of vessel industry, where high structural stiffness is required with small addition of weight. It is so significant to think of the effect of the variables in the design process of the sandwich structure for the concentrated loads. This paper describes the influence of design variables, such as core density, core thickness and face thickness ratio, on the strength of sandwich beam. The theoretical failure loads based on the 2-D elasticity theory agree well with the experimental yield or failure loads, which are measured at the three point bending laboratory test using AS4/3501-6 facing and polyurethane foam core sandwich beam. The comparison of those yield or failure loads was also done with the ratio of the top to bottom face thickness. The theoretical optimum condition is obtained by finding the intersection point of failure modes involved, which gives optimum core density of the sandwich beam for strength and stiffness. In the addition, the effect of unequal face thickness for the optimized and off-optimized sandwich beams for the strength was compared with the ratio of loading length to beam length, and the variations of strength and stiffness were discussed with the relative ratio of core to face mass.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.519-528
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• 2009

The effects of taping on the use of such measures for prevention have already been comprehensively described in the literature. However, few studies have analyzed ground reaction forces and postural stability with functional ankle instability subject during dynamic activities with ankle taping The purpose of this study was to identify the effects of ankle taping on ground reaction force and postural stability during jump landing. Fourteen players who has ankle instability were participated in this study. we used vicon and force platform. The application of taping who has ankle instability decreased DF and inversion angular velocity and peak vertical ground reaction force during landing. It also improved A-P cop, M-L cop in stability. The findings of this study support the use of taping as part of injury prevention for subject with functional ankle instability in clinical setting.

• Polymer(Korea)
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• v.35 no.2
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• pp.124-129
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• 2011

Wood plastic composites (WPCs) are attracting a lot of interest recently. In this study, wood flour/polyethylene (PE) composites panels comprised of a coupling agent and nanoclay were prepared by melt-blending followed by compression molding. Five maleic anhydride grafted polyethylene (MAPE) coupling agents were tested, and the best choice and its optimum content were determined. The mechanical properties of the WPCs were measured by UTM, and the thermal properties were measured by TGA, DMA, DSC, and TMA. Adding just a small amount (1 phr) of organoclay made the tensile and flexural strength and the crystallinity of the WPC somewhat increase and the storage modulus and dimensional stability of the WPC largely increase. SEM images showed that the coupling agent drastically improved wood flour/PE interfacial bonding. Selecting the best coupling agent optimized content and adding a small amount of organoclay resulted in a high performance wood flour/PE composite.

• The Korean Journal of Mycology
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• v.28 no.2
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• pp.88-92
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• 2000

Substrate improvement, maturation period and method of pinheading promotion were investigated to establish the culture method of Lyopyllum ulmarium which could obtained high yield in the short culture period. Rice bran+wheat bran (10%+10%) combination was selected from various additives, which showed vigorous growth of fruit body and high yield (133.8 g/850 cc). Oyster shells powder substance increased yield to 155.5 g per 850 cc capacity bottle. The suitable method for pinheading promotion was to stand the bottle reversely. The number of fruit bodies per 850 cc capacity bottle in this method was 27.2 stipes and bunch formation was good. When the maturation period of mycelium culture was 15 days to 30 days, pinheading period was 10 days. But when the maturing mycelium was 30 to 45 days, yield per 850 cc bottle was 148.2 g.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.257-264
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• 2020

The purpose of this study is to investigate the types and effects of rehabilitation by systematically examining the rehabilitation research for improving the shoulder ROM in breast cancer resection patients. For a systematic review, a total of 8 studies were finally selected through three databases including RISS. As a result of this study, the level of qualitative was 4 studies(50.0%) in level III, and the rehabilitation period varied from 4 weeks to 12 weeks. As for the type of rehabilitation, 3 studies(37.5%) were occupational therapy and physical therapy. The ROM of the shoulder joint was 7 studies(87.5%) of flexion, extension, and external rotation. A goniometer was used in 8 studies(100.0%) to evaluate the ROM of the joint as a measuring tool. This study is expected to provide basic data in the field of convergence when developing and applying interventional protocols for patients with limited ROM due to breast cancer resection.

• Composites Research
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• v.26 no.3
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• pp.170-174
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• 2013

Atmospheric glow plasma polymerization was applied to wood powder before fabricating polypropylene (PP) matrix composites. Seven different types of monomers (Oxygen, Benzene, CH4, Acrylic-acid, Hexafluoroethane, Trifluorotolune, Hexamethyl-disiloxane) were analyzed to determine the most suitable precursor for plasma polymerization. The surface energy was calculated from measured contact angle about each monomer on PP. Hexamethyl-disiloxane (HMDSO) had a highest surface energy and is selected as the most suitable monomer. Wood powder and polypropylene were mixed as pellets by twin screw extruder and then 50 wt% wood powder/PP composites were produced by an injection machine. Tensile strength and Flexural strength have improved by 7.59% and 12.43% at the maximum respectively. SEM (Scanning Electron Microscope) observation on the fracture surface revealed that the plasma polymerization have improved the interfacial bonding and the mechanical properties of the composites.

• Journal of the Ergonomics Society of Korea
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• v.27 no.4
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• pp.59-64
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• 2008

The aims of this study were to compare and analyze two types of deep cervical flexion exercises, craniocervical flexion and cervical flexion, and to ascertain their relative effects on neck and shoulder pain and functional improvement. The participants of the study were individuals who work in sedentary jobs in an office environment. 54 appropriate subjects were chosen and randomly divided into two groups: one group underwent a craniocervical flexion exercise program and the other a cervical flexion exercise program. The six week exercise program consisted of home exercises performed by each subject five times a week and education once a week. Neck-shoulder pain, muscle strengthening, cervical alignment were measured prior to commencement of the exercise programs and again after six weeks. At completion of the six week, both exercise programs decreased neck pain (p<.05). Forward head postures were reduced, and the craniocervical flexion exercise program was more effective in reducing forward head posture (p<.05). The maximum muscle strength and 50% of maximum muscle strength maintaining time of the deep cervical flexor muscles were significantly increased. There were no significant changes of the cervical lordotic curve. The results of this study showed deep cervical flexion exercise was effective in the treatment of neck and shoulder pain, however craniocervical flexion exercise was more effective than cervical flexion exercise.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.4 s.304
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• pp.21-30
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• 2005

In this paper, we propose lane detection and trackinB algerian using B-Snake as robust algorithm. One of chief virtues of Lane detection algorithm using B-Snake is that it is possible to specify a wider range of lane structure because B-Spline conform an arbitrary shape by control point set and that it doesn't use any camera parameter. Using a robust algorithm called CHVEP, we find the vanishing point, width of lane and mid-line of lane because of the perspective parallel line and then we can detect the both side of lane mark using B-snake. To demonstrate that this algorithm is robust against noise, shadow and illumination variations in road image, we tested this algorithm about various image divided by weather-fine, rainy and cloudy day. The percentage of correct lane detection is over 95$\%$.

• Journal of Adhesion and Interface
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• v.7 no.2
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• pp.26-31
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• 2006

In order to effectively improve interfacial adhesion strength between polypropylene (PP) and jute fiber, we particularly incorporated maleic anhydride grafted PP (MAPP) into the matrix through the environment-friendly process without an additional method of process and had better mechanical performances by providing the alignment into the natural fiber than those of the conventional fabrication technology such as an extrusion or injection molding. We also proposed hot pressing method which applied relatively low shear to the composites and confirmed the chemical bonds among the functional groups of MAPP and jute using FT-IR approach. The concentration of MAPP for maximum tensile strength and modulus was optimized at 3 wt%. Flexural properties had no noticeable tendency to increase with MAPP contents compared to tensile strength, which could probably be explained by the degree in wetting of PP/MAPP matrix.