• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.259-262
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• 2005

This paper deals with the shear strengthening effect of RC beams strengthened with carbon fiber sheets. Fifteen strengthened RC beams(including control beam) were experimentally evaluated to determine improvements in shear strength. The major parmeters of experiment variables are fiber sheet strengthening ratios and strengthening methods of fiber sheet(I-S, I-W, U-S, U-W type). Reinforced concrete beams strengthened with carbon fiber sheets were tested under the combined control of load. Considering strengthening ratios and strengthening methods of fiber sheet, shear capacity and failure mode of test specimens were evaluated. The results show that shear capacity of beams strengthened with fiber sheet is about $28.82\%$ in IS type, $20.49\%$ in IW type, $26.04\%$ in US type, $28.70\%$ in UW type higher than the strength of control beam.

• Textile Coloration and Finishing
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• v.12 no.5
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• pp.308-314
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• 2000

The dyeability of C. I. Disperse Violet 1 on polyester fiber in alkance including a small amount of water was investigated. Up to 1% of water in alkanes the dye uptakes were increased rapidly. The dyeing transition temperature of the polyester fiber in alkanes with 1% of water was $86.5^\circ{C}$ that is lower by $11^\circ{C}$ than $97.5^\circ{C}$ in alkanes only. This means that water plasticizes the polyester fiber, and that dyes begin to penetrate the polyester fiber at lower temperature. Addition of trichloromethane which is known as a strong plasticizer on polyester fiber, in alkanes, increased the dye uptakes of C. I. Disperse Violet 1 on polyester fiber at $100^\circ{C}$, but the dyeing transition temperature was lower by $3^\circ{C}$ than in alkanes only.

• International journal of steel structures
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• v.18 no.5
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• pp.1560-1576
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• 2018

With the aim to provide an efficient platform for the elastic-plastic analysis of steel structures, reinforced concrete (RC) structures and steel-concrete composite structures, a program iFiberLUT based on the fiber model was developed within the framework of ABAQUS. This program contains an ABAQUS Fiber Generator which can automatically divide the beam and column cross sections into fiber sections, and a material library which includes several concrete and steel uniaxial material models. The range of applications of iFiberLUT is introduced and its feasibility is verified through previously reported test data of individual structural members as well as planar steel frames, RC frames and composite frames subjected to various loadings. The simulation results indicate that the developed program is able to achieve high calculation accuracy and favorable convergence within a wide range of applications.

• Fiber Technology and Industry
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• v.10 no.3 s.39
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• pp.239-250
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• 2006

• Journal of Korean Academy of Nursing
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• v.27 no.1
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• pp.96-108
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• 1997

The purpose of this study was to determine the effect of endurance training prior to occurrence of muscle atrophy on the mass, myofibrillar protein content and fiber crossectional area of atrophied hindlimb muscles of rats. Adult female Wistar rats were trained prior to occurrence of muscle atrophy induced by hindlimb suspension. Training began on the 1st day for 10min /day at 15m /min on a 0% grade, training exercise increased daily in time and intensity so that by the 4th week rats were running 60min /day, at 34m /min on a i3.5% grade. Wet weight and relative weight of soleus, plantaris and gastrocnemius muscle decreased significantly after seven days of hindlimb suspension. Wet weight and relative weight of soleus tended to increase and that of plantaris and gastrocnemius tended to decrease in the exercise group as compared to the control group. Myofibrillar protein content of soleus and gastrocnemius tended to increase and that of plantaris tended to decrease in the endurance trained group as compared to the control group. Fiber crossectional area of Type I, II fiber in soleus and plantaris muscle tended to increase in the exercise group as compared to the control group. Wet weight and relative weight of soleus. plantaris and gastrocnemius decreased significantly, myofibrillar protein content of soleus, plantaris and gastrocnemius increased in hindlimb suspended rats following endurance training as compared to the control group. There was no change in fiber type percentage and crossectional area of type I and II fiber in soleus muscle and that of type I and IIfiber in plantaris muscle decreased in the hindlimb suspended rats following endurance training as compared to the control group. Wet weight and relative weight of soleus and plantaris tended to increase, that of gastrocnemius increased significantly, myofibrillar protein content of soleus and plantaris muscle increased significantly and that of gastrocnemius tended to increase in the hindlimb suspended rats following endurance training as compared to sedentary rats following endurance training. Crossectional area of type I fiber of soleus muscle tended to increase. that of type I fiber of plantaris muscle increased significantly and that of type II fiber tended to increase in hindlimb suspended rats following endurance training as compared to sedentary rats following endurance training. The results suggest that endurance training prior to occurrence of muscle atrophy can attenuate the decrease of mass, myofibrillar protein content and fiber crossectional area induced by hindlimb suspension.

• Composites Research
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• v.33 no.5
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• pp.296-301
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• 2020

Laminated composite materials have excellent in-plane properties, but are vulnerable in thickness directions, making it easy to delamination when bending and torsion loads are applied. Thickness directional reinforcement methods of composite materials that delay delamination include Z-pinning, Stitching, Tufting, etc., and typically Z-pinning and Stitching method are commonly used. The Z-pinning is reinforcement method by inserting metal or carbon pin in the thickness direction of prepreg, and the conventional stitching process is a method of reinforcing the mechanical properties in the thickness direction by intersecting the upper and lower fibers on the preform. In this paper, I-fiber stitching method, which complement and improve weakness of Z-pinning and Stitching method, was proposed, and the static strength of composite single-lap joints using I-fiber stitching process were evaluated. The single-lap joints were fabricated by a co-curing method using an autoclave vacuum bag process. The thickness of the composite adherend was fixed, and 5 types of specimens were manufactured with varying the stitching pattern (5×5, 7×7) and angle (0°, 45°). From the test, the failure load of the specimen reinforced by the I-fiber stitching process was increased by up to 143% compared to that of specimen without reinforcement.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.1 no.1
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• pp.57-72
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• 2003

This study conducts electrical stimulation to male white rat of Spargue-Dawley which is 7 weeks, has the weight of 240 g and is seemingly healthy for one or two weeks by means of neuromuscular electrical stimulator in order to examine the effects of neuromuscular electrical stimulation on its gastrocnemius, measures change of weight of gastrocnemius, serum and enzyme activity and then obtains the following conclusions. There is little difference in AST and CPK of weight and serum of gastrocnemius after one or two weeks of conducting neuromuscular electrical stimulation in all experimental groups. On the one hand, as a result of histochemical observation, NMES I group showed hypertrophy of perimysium and increase of sectional diameter of muscle fiber compared to comparison group, but NMES II group showed a similar result to comparison group. When ultrasubstructure was observed under electron microscope, I-type muscle fiber of NMES I group showed well-arranged mitochondria and it was similar to comparison group. II-type muscle fiber showed a large quantity of glycogen granules within sarcoplasmatic and the extension of luminal of T-tubule. I-type muscle fiber of NMES II group had small mitochondria and showed the vacuolar degeneration of mitochondria and extended T-tubule. II-type muscle fiber showed the extension of agranule cytoplasma reticulum with T-tubule and the reduction of amount of glycogen granule within partial sarcoplasmatic.

• Fibers and Polymers
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• v.4 no.3
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• pp.124-128
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• 2003

Dark brown Alpaca fiber was reduced in shade via selective bleaching with peroxide. Two selective oxidative bleaching methods were tested on alpaca top to assess their effectiveness for color removal and fiber quality properties. Color change, bundle strength, weight loss, fiber diameter, surface modification, dye-ability and dye wash fastness were assessed for both methods and compared with the original brown top. Bleach method 1 (BL-I) showed little surface modification, 5.8% weight loss and 2.4% strength loss. D1925 yellowness index was reduced to 74.3 from 83.1 and provided a good base for the dyeing of medium to deep shades. Bleach method 2 (BL-II) displayed considerable surface modification, 7.8% weight loss and 18% strength loss. BL-II also resulted in a mean diameter reduction of 1.9 micron during bleaching. Yellowness was reduced to 64.5 from 83.1 and provided a very good base for the dyeing of medium to deep shades. BL-I showed better exhaustion of the premetallised dye Lanaset Violet B than BL-II. Wash fastness for BL-II was 1 grey scale unit poorer than BL-I. BL-II showed far better color clarity at pale depths however the wash fastness of the finished product was not good enough to maintain the depth or clarity of the color. BL-I showed poorer clarity of color but exhibited better wash fastness results.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.135-139
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• 2016

I propose a vector passive harmonic mode-locked fiber laser based on topological insulator Bi2Se3 interacting with a fiber taper with a diameter of 7 μm. The particles of topological insulator are deposited uniformly onto the fiber taper with light pressure effect. By incorporating the fabricated saturable absorber into an Er-doped fiber laser cavity, stable mode-locked fiber is obtained. Due to the intense evanescent field of the fiber taper, strong confinement of light enhances the nonlinearity of the laser cavity, and passive harmonic mode-locking is performed. I observe a maximum harmonic mode-locking of 356th, corresponding to a frequency of 3.57 GHz. The pulse duration is 824 fs, and the full width at half maximum of the spectrum is about 8.2 nm. The polarization dependent loss of the saturable absorber is ~ 2.5 dB in the wavelength range of the C band. As the cavity contains no other polarization dependent device, the mode-locked laser is functioning in the vector state. The harmonic order vs pump power is investigated. To the best of our knowledge, this report is the highest frequency mode-locked fiber laser based on Bi2Se3. Experimental results indicate that the topological insulator Bi2Se3 functioning with a thin fiber taper is effective for vector harmonic mode-locking.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.1
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• pp.99-106
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• 2000

In order to investigate the applicability of lyocell fiber to filter paper, papper sheets were manufactured with the addition of lyocell fibers in various length(1.5 denier: 2, 3, 4mm) and content(10, 30, 50%) and their physical characters, such as fibrilation rate, adsorption efficiency of methylene blue(MB), paper formation, and crimping ability, etc, were tested. The level of main fibrilation from lyocell fiber was higher in wet beating process than that in free beating because of the higher strength of lyocell fiber compared with wood fiber. Fibrilation could be observed at the degree of beating over 30$^{\circ}$ SR in wet beating with Valley beater. The air permeability and tear factor of the paper increased and the paper formation index decreased according to the increase of fiber length. The weak binding force of lyocell fiber in spite of its higher fiber strength, might be a limitng factor in addition of lyocell fiber to the natural wood pulp in manufacturing the paper having the needed physical properties. High contents of wood pulp decreased air permeability, the breaking length, tear factor, the bursting strength, and paper formation index in paper sheets. As the contents of lyocell increased from 10% to 100%, the adsorption efficiency of MB was elevated to 1.7-7.9 times compared with that in 100% wood pulp. But the length of lyocell fiber did not affect the MB adsorption.