• Carbon letters
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• v.20
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• pp.53-61
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• 2016

The reportedly synergistic effects of carbon nanotubes (CNTs) and graphene hybrids have prompted strong demand for an efficient modifier to enhance their dispersion. Here, we investigated the ability of poly(acrylonitrile) (PAN) to overcome the van der Waals interaction of multi-walled CNTs (MWCNTs) and graphene by employing a simple wrapping process involving ultrasonication and subsequent centrifugation of PAN/MWCNT/graphene solutions. The physical wrapping of MWCNTs and graphene with PAN was investigated for various PAN concentrations, in an attempt to simplify and improve the polymer-wrapping process. Transmission electron microscopy analysis confirmed the wrapping of the MWCNTs and graphene with PAN layers. The interaction between the graphitic structure and the PAN molecules was examined using proton nuclear magnetic resonance, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and Raman spectroscopy. The obtained results revealed that the cyano groups of the PAN molecules facilitated adhesion of the PAN molecules to the MWCNTs and graphene for polymer wrapping. The resulting enhanced dispersion of MWCNTs and graphene was verified from zeta potential and shelf-life measurements.

• Physical Therapy Rehabilitation Science
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• v.13 no.1
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• pp.95-105
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• 2024

Objective: The purpose was to investigate changes in mechanical properties, range of motion, and grip strength of the forearm muscle in 13 students depending on the wrapping direction of the floss band. Design: A single-blind, crossover study Methods: Subjects were randomly assigned to the wrapping direction of the flossing band and then performed a concentric exercise of the wrist flexors using a Flex-Bar. Intervention A applied the flossing band in a right spiral direction, Intervention B applied the flossing band in a left spiral direction, and Intervention C performed the exercise alone. All subjects used their dominant right hand, and pre- and post-assessments were conducted between interventions. To analyze differences in changes between groups pre- and post-, all results were subjected to one-way ANOVA, followed by Scheffe's test as a post-hoc analysis. The paired samples t-test was used to analyze the difference between pre- and post-change within groups. Results: First, in the mechanical properties of the Flexor carpi ulnaris (FCU) muscle, interventions A and B significantly improved muscle tone and stiffness than intervention C (p<0.05), and intervention A showed a significant decrease in decrement (muscle elasticity) than intervention B (p<0.05). Second, interventions A and B showed significant improvement in grip strength than intervention C (p<0.05). Conclusions: The right spiral direction of the flossing band tended to increase the elasticity of the muscles compared to the left spiral direction. Therefore, in future studies, it is necessary to choose the direction of the flossing band to increase the elasticity of the muscles.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.11a
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• pp.193-199
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• 2006

Fruit bagging paper is used for protecting of fruits from insect and/or microorganisms. Generally, fruit bagging paper controled light, temperature and humidity and then it is used for good fruit color, size and taste. The physical properties of conventional(domestic and abroad) fruiting bag and wrapping paper were analyzed and compared to each other. And also, the optical properties of conventional(domestic and abroad) fruiting bag and wrapping paper were analyzed and compared to each other. The chemical additives and residual herbicide in conventional fruiting bag and wrapping paper were analyzed and compared to each other. The analyzed data was bench marked for developing water repelling paper and embossing paper.

• Applied Chemistry for Engineering
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• v.23 no.4
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• pp.372-376
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• 2012

Carbon nanotubes (CNT) are considered as one of ideal nano-fillers in the field of composites with their excellent electrical, mechanical, and thermal properties. Therefore CNT composites are increasingly used in fabricating conductive materials, structural materials with high strength and low weight, and multifunctional materials. The main problem of the CNT composites is difficulty in the dispersion of CNT in the polymer matrix. In this study multi-walled carbon nanotubes (MWNT) were pretreated by the physical process utilizing a wrapping method. After the pretreatment polymer/MWNT nanocomposites were prepared by melt processing. The effect of functionalization MWNT by wrapping with styrene acrylonitrile (SAN) on the mechanical and electrical properties of acrylonitrile butadiene styrene resin (ABS)/MWNT composites was studied by comparing the properties of ABS mixed with the neat MWNT. Electrical and mechanical properties of ABS/MWNT nanocomposites were studied as a function of the functionalization and content of MWNT. The tensile strength of the ABS/MWNT nanocomposites increased, but the impact strength decreased. The polymer wrapping in ABS system has little effect on the improvement of electrical properties.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.3
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• pp.1-11
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• 2007

To evaluate the quality of waste paper used for the manufacture of linerboard, the types of papers and foreign materials in compressed waste paper currently used were investigated. The recycled fibers were obtained from printing paper, newspaper, wrapping paper, white coated paperboard and corrugated container. Their fibers were observed by using a microscope, and the mechanical properties of the recycled papers manufactured from the recycled fibers were investigated. The compressed wastepaper was composed of 54% paperboard, 20% printing paper, and 20% newsprint. The content of foreign materials was about 4%, showing higher contents compared to 1% of foreign substances provided by Korea paper manufacturers' association. The types of foreign materials were various, which include vinyls, plastics, metals, woods, styrofoams, and cloths. Sound fibers were generally observed in the recycled fibers of printing papers and wrapping paper. The recycled fibers of white coated board, corrugated container and newsprint showed to be generally damaged. The whiteness of each recycled fiber were highly affected by pulp bleaching and ink-particle mixing conditions. The values of breaking length and burst index were lower than those for corrugating medium and liner board specified in KS. Although the anatomical characteristics of recycled fibers varied, their strengths appeared to be similar. This result may be explained by the use of non-deinked fiber.

• Polymer(Korea)
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• v.37 no.4
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• pp.526-532
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• 2013

The effect of CNT dispersion method on rheological and electrical properties of polystyrene/carbon nanotube (PS/CNT) nanocomposites via latex technology was compared. The nanocomposites were prepared through freeze-drying the dispersed suspension comprised of CNTs and PS particles. In this study, physical dispersion method, either sodium dodecylsulfate (SDS) addition or polyvinyl pyrrolidone (PVP) wrapping, was employed to prevent the deterioration of intrinsic properties of CNT caused by chemical modification. The physical method applied to latex technology was very effective in CNT dispersion. With SDS addition, the enhancement of rheological properties was low compared to PVP wrapping because the properties of matrix were deteriorated due to the incorporation of low molecular weight SDS. The electrical percolation threshold of PS/SDS-stabilized CNT and PS/PVP-wrapped CNT nanocomposites was 0.23 and 0.90 wt%, respectively. The enhancement of electrical conductivity was low in the case of PVP wrapping because the non-conducting PVPs wrapped around CNT restricted the electrical connection between CNTs.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.4
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• pp.135-145
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• 2023

Purpose : The purpose of this study was to discover which breathing technique is more effective in improving respiratory function by applying different breathing techniques-the chest expansion respiratory technique and the abdominal expansion respiratory technique-to adults in the same aerobic exercise situation. Methods : In this study, 30 people were randomly assigned to two groups: chest expansion respiratory technique with aerobic exercise (A group) and abdominal expansion respiratory technique with aerobic exercise (B group). Group A was asked to breathe after wrapping their rib cage with an elastic band, and Group B was asked to breathe after wrapping their abdomen with an elastic band. A total of 3 sets of 30 breaths were performed, 3 times a week for 6 weeks. For statistical processing, an independent t-test was used to verify homogeneity between the two groups, and a repeated measure analysis of variance (ANOVA) was used to compare differences according to the period for each group. Results : The changes in FVC and FEV₁ for each group following 6 weeks of intervention are as follows. In comparison according to the intervention period, there was a significant increase in all groups depending on the timing of measurement (p<.05), and as a result of the inter-subject effect test, there was no significant difference between groups (p>.05). In addition, there was no interaction effect between period and group (p>.05). Conclusion : The conclusion of this study is that FVC and FEV₁ values increased according to the intervention period in both groups; therefore, it can be suggested that flexible breathing techniques can be applied depending on the patient's physical situation when applying a breathing program to improve respiratory function.

• Textile Coloration and Finishing
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• v.13 no.6
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• pp.428-434
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• 2001

This study surveys the fiber behavior in yam formation and the Physical properties of Solo-spun yarn. The specimens were made by six types of Solo-spun rollers with fixed twist multiplier In the previous part, the physical properties such as yarn count, evenness, strength, and breaking elongation of these yams were compared with the properties of ring shun yarns and analysed with the mechanism of Solo-spun yarn formation. In the second part of this report, the abrasion resistance and hairiness were discussed wish respect to the micro yarn structures. The narrower the groove width of Solo-spun roller is, the more active the bulk fibers migration is. The Solo-spun film structure has two groups. One is shorter than the others one in longitudinal direction of yarn and has the same structure as ring-spun yarn, which is derided from the smooth zone on the surface of Solo-spun roller. The other one is longer than the former and there are the wrapping fibers. This part is derived from the conflicted grooves on the surface of Solo-spun troller.

• Textile Coloration and Finishing
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• v.13 no.6
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• pp.70-70
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• 2001

This study surveys the fiber behavior in yarn formation and the Physical properties of Solo-spun yarn. The specimens were made by six types of Solo-spun rollers with fixed twist multiplier In the previous part, the physical properties such as yarn count, evenness, strength, and breaking elongation of these yarns were compared with the properties of ring spun yarns and analysed with the mechanism of Solo-spun yarn formation. In the second part of this report, the abrasion resistance and hairiness were discussed with respect to the micro yarn structures. The narrower the groove width of Solo-spun roller is, the more active the bulk fiber migration is. The Solo-spun yarn structure has two groups. One is shorter than the other one in longitudinal direction of yarn and has the same structure as ring-spun yarn, which is derived from the smooth zone on the surface of Solo-spun roller. The other one is longer than the former and there are the wrapping fibers. This part is derived from the conflicted grooves on the surface of Solo-spun roller.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.07a
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• pp.52-58
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• 1999

'98년 말을 기준으로 우리나라의 젖소는 15.7천여 농가에서 539천두가 사육되고 있다. 이는 낙농농가 호당 평균 약 34두가 사육되는 전업규모의 영농을 하고 있음을 의미한다(서울 우유협동조합 1999). 그러나 현재 낙농농가는 대부분 수입 사료에 의존하여 생산비의 대부분을 사료비가 차지하고 있다. 젖소의 사양에 있어 이상적인 조사료와 농후사료의 급여비율은 60:40으로 알려지고 있으나 우리나라의 경우는 33:67로 조사료 보다 농후사료의 급여비율이 굉장히 높은 수준에 있다(농촌진흥청 1998). (중략)