• Textile Coloration and Finishing
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• v.32 no.2
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• pp.111-120
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• 2020

In this study, lignin/chlorinated poly(vinyl chloride)(CPVC) blended fibers have been produced for the development of low-cost carbon fiber. Carbon fiber manufacturing was accomplished through stabilization and carbonization process. The lignin/CPVC blended fibers were prepared by wet spinning method. Dimethylacetamid e(DMAc) and cychlohexanone in a ratio of 5:1(wt%) was employed as co-solvent. The ratio of lignin/CPVC was prepared at 0/10, 1/9, 2/8, 3/7, 4/6, and 5/5(wt%). The spinning solution was extruded at a rate of 0.1 to 0.4ml/min according to the blending ratio. The speed of the rollers was the same for all ratios(draw ratio=1). Analysis of fiber cross-section by scanning eletron microscopy(SEM) showed that as the lignin ratio increased in the same coagulation bath and distilled water, the pore size of the spinning fiber decreased. Therefore, the highest tensile strength of the blending fibers was 6.3±1.2MPa at the 5/5 ratio. The carbon fiber also showed the best tensile strength of 120.78±2.43MPa at 5/5 ratio.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.2
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• pp.71-76
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• 2016

PURPOSE: The purpose of this study was to compare isometric contraction of deltoid middle fiber between elastic band and light dumbbell on various shoulder abduction angle. And this study intends to examine the compare with isometric contraction on deltoid middle fiber in various abduction angle of shoulder joint. METHODS: The participants of this study were Korean healthy adult in their 20s (n=60). The 8 channel surface electromyography was used to measure activity of the deltoid middle fiber at isomeric contraction on various abduction angle: $0^{\circ}$, $30^{\circ}$, $60^{\circ}$, $90^{\circ}$, $120^{\circ}$ of shoulder joint using elastic band: red color Theraband and dumbbell: 2kg. The data used in the analysis of the present study was the root mean square. RESULTS: The deltoid middle fiber activation was not significantly different between elastic band and dumbbell at each abduction angle. The deltoid middle fiber activation significantly increased as more to increased shoulder abduction angle in elastic band and dumbbell. CONCLUSION: The elastic band and dumbbell was to provide the similarly load to the deltoid middle fiber isometric contraction on all of the shoulder abduction angle. The deltoid middle fiber activation increased as more to increased shoulder abduction angle in elastic band and dumbbell. These results may be an important reference in development of exercise on shoulder joint.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.2
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• pp.47-54
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• 1998

Refining is one of the most important processes of fiber treatment that provides optical and physical properties of final paper products. The evaluation method of refining progress is usually freeness (CSF) or wetness (SR) test because of its rapidity and convenience. However, there are some deficiencies in using freeness or wetness test to evaluate pulp fibers accurately because its results are more influenced by fines contents than extent of fibers treatment. The objective of this study is to show the deficiency of wetness in evaluating the refining process. For this, beating is done by varying the beating load. Handsheets are made after beating until 25 and $32^{\circ}C$ SR, and then paper properties are measured. Refined fibers are analyzed by fiber length, fines contents, curl, kink, WRV, and zero-span tensile strength. The results show that longer beating time is required to reach the same wetness at lower beating load. There are differences in the average fiber length, distribution curve of fiber length, fines contents, curl, kink, WRV of long fiber fraction, drainage time, and zero-span tensile strength of rewetted sample at different beating load. At the low beating load in the same wetness, apparent density, breaking length, burst strength, and tear strength are higher, while opacity and air permeability are lower than those of the high beating load. Using Page s equation, which shows the relationship among tensile strength, intrinsic fiber strength, and interfiber bonding strength, interfiber bonding strength is calculated and analyzed to explain final paper properties. At $25^{\circ}C$ SR, interfiber bonding strength is only slightly higher at 2.5kgf beating load, while the intrinsic fiber strength is substantially higher. At $32^{\circ}C$ SR, intrinsic fiber strength is a little bit higher at 2.5kgf beating load, and interfiber bonding strength is remarkably higher than those of 5.6kgf beating load. These results can be used to explain the different properties of the final paper at selected beating loads.

• The Korean Journal of Food And Nutrition
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• v.16 no.4
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• pp.372-378
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• 2003

The volatile components of cinnamon bark were extracted by using different isolation methods, simultaneous distillation extraction (SDE) and solid phase microextraction (SPME). Then the volatile components were analyzed by gas chromatography(GC) and mass selective detector(MSD). 30 compounds were identified in cinnamon bark. In SPME technique, several factors influencing the equilibrium of the aroma compounds between sample and SPME fiber was taken into account, including the kind of SPME fiber, extraction temperature and extraction time. Four different SPME fibers were tested, namely polydimethylsiloxane (PDMS), poly acrylate(PA), divinyl- benzene-carboxen-polydimethylsiloxane (DVB/CAR/PDMS) and carbowax/divinylbenzene(CW/DVB). Among these SPME fiber, PDMS coating fiber showed the best results. The profile of volatile compounds of cinnamon bark at different extraction temperature and extraction time were investigated by 100$\mu\textrm{m}$ PDMS fiber.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.4
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• pp.49-58
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• 2011

The maximum drying shrinkage velocity was proposed to verify bulk and stiffness improvement mechanism during drying according to papermaking parameters. It was based on the wet-web shrinkage behavior without the restraint of wet-web during drying, so intact drying impact could be measured. Bulking agent reduced the drying shrinkage and the maximum drying shrinkage velocity, so paper bulk increased and paper strength decreased. When adding cationic starch to stock with the bulking agent for strengthening, the bulk was increased further with additional decreasing of the drying shrinkage and the maximum drying shrinkage velocity. Paper strength also increased except tensile stiffness index with decreasing the drying shrinkage and the maximum drying shrinkage velocity. When using additional strength additives for strengthening of fiber interfaces extended by bulking agent and cationic starch, amphoteric strength additive increased paper stiffness without loss of paper bulk. It was considered that the added amphoteric strength additives were cross-linked to the stretched cationic starch and this cross-linking increased elasticity of fiber-polymer-fiber interfaces without changing the drying behavior. Paper bulk could be increased with decreasing the maximum drying shrinkage velocity. The drying shrinkage of paper also could be controlled by fiber-to-fiber bonding interfaces by the bulking agent. In this case, paper strength including stiffness was decreased by reducing fiber-to-fiber bonding but it could be improved by strengthening fiber-to-fiber interfaces with polymer complex without loss of bulk.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.3
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• pp.53-63
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• 1992

To investgate the fracture behavior of the steel fiber reinforced concreate, the specimens with different steel fiber contents of 0.0%, 0.5%, 1.0%, 1.5%, were made and notched with differents notch depth ratios of 0.0,0.2, 0.4, 0.6, and the three point bend tests were followed. Test results of 16 different types of above combined specimens were summarized as follows. 1.The load line deflection contents were found to increase 5%, 16%, 19%, respectively, compared to the unnotched specimen with the increased of initial notch depth ratio to 0.2,0.4, 0.6, respectively. 2.The frexural strength were found to decrease 14%, 16%, 21 %, respectively, compared to the unnotched specimen with the increase of initial notch depth ratio to 0.2, 0.4, 0.6,respectively. 3.The stress intensity factors of the steel fiber reinforced concrete were found to increase 1.1 1.5 1.9 times, respectively, compared to the concrete with no steel fiber content with the increase of fiber content to 0.5%, 1.0%, 1.5%, respectively. 4.The influence of the mass of the steel fiber reinforced concrete to the whole fracture energy was found to be minor with 6~8 % contribution. 5.The fracture energy of the steel fiber reinforced concrete, considering the load-deflection curve and concrete mass was found to be approximately 350-380kg m/m$^2$. 6.The regression analysis through the relationship between the compressive(Oc)/tensile (OT) strength and fracture energy(Gf) showed that the fracture energy of the steel fiber reinforced concrete could be predicted as follows. Gf= 19.2662 Oc - 3940.4 Gf= 246.876 OT- 6008.8

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.188-194
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• 2011

We analyze transmission performance of radio frequency signal in WDM-ROF (wavelength division multiplexing - radio over fiber) system employing photonic crystal fiber. In a WDM-ROF system employing conventional single-mode fiber, transmission performance of radio frequency signal is analyzed depending on each WDM channel. In this case, each WDM channel experiences power fluctuation of received RF signal in remote node because of double sidebands of the modulated signal and wavelength dependent dispersion of single mode fiber. This RF power fluctuation acts as a design constraint in viewpoint of system design. By employing photonic crystal fiber (PCF) with dispersion compensation characteristics, the transmission performance of RF signal can be improved compared with the case with SMF only.

• Restorative Dentistry and Endodontics
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• v.38 no.4
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• pp.215-221
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• 2013

Objectives: To determine the retentive strength and failure mode of undercut composite post, glass fiber post and polyethylene fiber post luted with flowable composite resin and resin-cement. Materials and Methods: Coronal parts of 120 primary canine teeth were sectioned and specimens were treated endodontically. The teeth were randomly divided into 6 groups (n = 20). Prepared root canals received intracanal retainers with a short composite post, undercut composite post, glass fiber post luted with flowable resin or resin-cement, and polyethylene fiber post luted with flowable resin or resin-cement. After crown reconstruction, samples were tested for retentive strength and failure mode. Statistical analysis was done with one-way ANOVA and Tukey tests (p < 0.05). Results: There were statistically significant differences between groups (p = 0.001). Mean bond strength in the undercut group was significantly greater than in the short composite post (p = 0.030), and the glass fiber post (p = 0.001) and the polyethylene fiber post group luted with resin-cement (p = 0.008). However, the differences between the undercut group and the groups with flowable composite as the luting agent were not significant (p = 0.068, p = 0.557). Adhesive failure was more frequent in the fiber post groups. Conclusions: Although the composite post with undercutting showed the greatest resistance to dislodgement, fiber posts cemented with flowable composite resin provided acceptable results in terms of retentive strength and fracture mode.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.1
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• pp.64-67
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• 2000

Jellies enhancing physiological functions were prepared with using 5 and 10% dietary fiber isolated from ascidian (Halocynthia roretzi) tunic collected from recycled seafood waste. The texture development of the samples was examined with two-bite compression test and analyzed using five sorts ofrheological parameters with texture profile analysis as follows; hardness, adhesiveness, springiness, cohesiveness and gumminess. All the rheological parameters decreased in the fiber enhanced jellies. However, the springiness and cohesiveness increased slightly in the fiber enhanced jellis. Hunter L' and d' values increased in the fiber enhanced jellies and accordingly the color was light yellow. a' value showed green with the addition of fiber. As a result of sensory evaluations, the color and overall acceptability of 10% fiber enhanced jelly were significantly different at p<0.05. The 10% fiber enhanced jelly was noted as having high sensory scores and peferable acceptability.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.377-380
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• 2008

The material and mechanical properties in the high temperature area of 40 to 100 MPa high strength concrete structural member was identified based on mixing of fiber cocktail and the structural element fire behavior simulation through the finite element analysis method (ABAQUS) was interpreted. The results are as follows. First, it was interpreted that the test specimen with concrete fiber cocktail mixed was more controllable in the maximum shrinkage than the one with concrete fiber cocktail not mixed the controllable range was about 25% to 55%. This means that shrinkage is controllable through mixing of fiber cocktail for the high strength concrete columns. Second, this study didn't consider the explosive spalling by the pore pressure within high strength concrete. If the properties for the pore pressure within high strength concrete is considered and database by strength and by inner temperature of various high strength concrete and steel materials are established in the future, it is interpreted that the technical foundation will be laid for performance based design of fire resistant construction.