• Journal of the Korean Geosynthetics Society
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• v.2 no.1
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• pp.27-37
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• 2003

The factors affecting shear strength and friction characteristics of the fiber-mixed soil can be classified into engineering properties of soil; particle-size, distribution, and particle shape, physical and mechanical properties of fiber; shape, length, diameter, tensile strength, elastic modulus, friction coefficient, and mixed ratio and external factors; confined stress and compaction condition. In this study, a series of shear friction tests and pull-out tests were performed to evaluate the friction properties of fiber-mixed soil according to soil type, fiber type, fiber mixed ratio and compaction degree. The materials and test conditions used in this study are as follows. Soils: SM and ML; mixing fibers: three types of polypropylene fibers(net type 38mm and 60mm, and line type 60mm); reinforcement: geogrid; mixing ratio: 0.2% and 0.3%; degree of compaction : 85% and 95%.

• Korean Journal of Optics and Photonics
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• v.15 no.5
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• pp.415-422
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• 2004

We propose and present a new multiplexed bend loss type single-mode fiber-optic sensor system for displacement measurement in order to measure the displacement of several mm of civil engineering structures such as bridges and buildings. We make a bend loss type fiber-optic sensor for measuring displacements using the signal difference between two reflection signals due to various bend losses generating at a pair of optical connectors by using the optical time domain reflectometer. And we fabricate a multiplexed bend loss type fiber-optic sensor detecting linear displacements of 4 measuring positions of an object by setting these new 4 fiber-optic sensors on a single mode fiber simultaneously. We find that the multiplexed fiber-optics displacement sensor has linearity of 0.9942, maximum displacement of 6 mm, and accuracy of 6% for 4 measuring points.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.322-322
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• 2010

For boron doping on n-type silicon wafer, around $1,000^{\circ}C$ doping temperature is required, because of the relatively low solubility of boron in a crystalline silicon comparing to the phosphorus case. Boron doping by fiber laser annealing and lamp furnace heat treatment were carried out for the uniformly deposited p-a-Si:H layer. Since the uniformly deposited p-a-Si:H layer by cluster is highly needed to be doped with high temperature heat treatment. Amorphous silicon layer absorption range for fiber laser did not match well to be directly annealed. To improve the annealing effect, we introduce additional lamp furnace heat treatment. For p-a-Si:H layer with the ratio of $SiH_4:B_2H_6:H_2$=30:30:120, at $200^{\circ}C$, 50 W power, 0.2 Torr for 30 min. $20\;mm\;{\times}\;20\;mm$ size fiber laser cut wafers were activated by Q-switched fiber laser (1,064 nm) with different sets of power levels and periods, and for the lamp furnace annealing, $980^{\circ}C$ for 30 min heat treatment were implemented. To make the sheet resistance expectable and uniform as important processes for the $p^+$ layer on a polished n-type silicon wafer of (100) plane, the Q-switched fiber laser used. In consequence of comparing the results of lifetime measurement and sheet resistance relation, the fiber laser treatment showed the trade-offs between the lifetime and the sheet resistance as $100\;{\omega}/sq.$ and $11.8\;{\mu}s$ vs. $17\;{\omega}/sq.$ and $8.2\;{\mu}s$. Diode level device was made to confirm the electrical properties of these experimental results by measuring C-V(-F), I-V(-T) characteristics. Uniform and expectable boron heavy doped layers by fiber laser and lamp furnace are not only basic and essential conditions for the n-type crystalline silicon solar cell fabrication processes, but also the controllable doping concentration and depth can be established according to the deposition conditions of layers.

• 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.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.3
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• pp.163-171
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• 2001

Lateral confinement pressure generate improvements in strength and ductility of confined concrete. Carbon fiber sheets have a lot of merits, such as light weight, high strength and ease for construction, when it is applied to the defected structural member for the strengthening of shear and flexure. The purpose of this experimental study is to evaluate the strength characteristics of the reinforced concrete column confined with carbon fiber sheets. The main variables in this test are concrete strength ($290kgf/cm^2$ called N type, $505kgf/cm^2$ called H type) and pre-loading. In the test, a total of twelve specimens, which were all $10{\times}10cm$ in size, 117 cm in length, have a 2.85 reinforcement ratio, have been used. The results indicate that the strength was enhanced 26%~30% in N type, 11%~16% in H type specimens which was confined with carbon fiber sheets.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.5
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• pp.665-671
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• 2010

Muscle fiber characteristics and their relationship to water-holding capacity of longissimus dorsi (ld) muscle were studied in Brahman (BRA) and Charolais (CHA) crossbred bulls fattened under practical farm conditions. Thirty-four BRA and 34 CHA bulls were randomly selected and slaughtered at 500, 550 and 600 kg live weight. Parameters of water-holding capacity such as drip, ageing, thawing, cooking and grilling loss were determined. Muscle fiber characteristics were conducted for muscle fiber type percentage and cross-sectional areas of slow- and fast-twitch fiber types, and correlation coefficients to water-holding capacity parameters were calculated. Results showed that CHA meat had a better water-holding capacity (less ageing, thawing and grilling loss) when compared with BRA, whereas slaughter weights had no significant effects on these parameters. Furthermore, there were no significant differences between genotypes and slaughter weights in muscle fiber type percentage and cross-sectional areas of ld muscle. Slow- and fast-twitch fiber types of all experimental groups averaged 24.4 and 75.6%, respectively. Cross-sectional areas of fast-twitch fibers had almost twice the size of slow-twitch fibers (6,721 and 3,713 ${\mu}m^2$, respectively). The correlation between muscle fiber area and water-holding capacity indicated that muscles with larger fiber areas had a lower drip and ageing loss but a higher cooking and grilling loss.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.61-64
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• 2009

This study is reviewed fire resistance characteristics of high strength concrete according to changes in PP fiber mixing ratio and type of fine aggregate, and the results can be summarized as follows. As fire resistance characteristics, all plain crushed sands prevented spalling regardless of increase in mixing ratio of PP fiber. Mixtures other than the plain showed satisfactory spalling prevention when 0.05 % or more of PP fiber was mixed. After the fire resistance experiment, the plain showed 5.5 % of mass loss rate when fiber was not mixed and others could not be measured. According to increase in mixing ratio of fiber, river sand with fineness modulus of 2.2 showed most satisfactory result of 34 %${\sim}$42 %. Mass loss rate after fire resistance experiment was most satisfactory at about 10 % in the plain crushed sand without mixing of fiber, and all other mixes with 0.05 % PP fiber or more showed 5${\sim}$10 % loss rate.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.104-104
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• 2003

Geosynthetic Reinforcements - membrane drawn type, warp/knitted type, junction bonded type and composite type geogrids, strip type reinforcement - were used to compare the long-term perfor-mance by total factor of safety with reduction factors during service periods. To evaluate the reduction factors, wide-width tensile property, installation damage, creep deformation, chemical and biological degradation tests were performed. Long-term design strengths of geosynthetic reinforcements were calculated by using GRI standard Test Method GG4.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.10
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• pp.1529-1534
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• 2008

The aim of this study was directed at exploring the possible use of muscle fiber characteristics as new selection traits for improving both porcine lean meat production and quality. A total of 174 (114 Yorkshire, 30 Landrace, and 30 Meishan) pigs were used for this study, and lean meat production ability was estimated by backfat thickness and loin eye area. The Longissimus dorsi muscle was taken in order to measure meat quality and muscle fiber characteristics. Due to the high correlations between total muscle fiber number and most of the performance traits, all pigs were classified into three groups (low, intermediate, or high) by total muscle fiber number using cluster analysis. The high group had the highest loin eye area (p<0.001). The meat quality traits were within normal ranges as reddish pink, firm, and nonexudative (RFN) pork, but the groups classified as intermediate and high had relatively large drip loss percentages (p<0.05), produced more than twice the amount of pale, soft, and exudative (PSE) pork as compared to the low group. The group with a high total muscle fiber number was further classified, based on type 2b fiber percentage, into low or high groups by cluster analysis. The results showed that the low type 2b fiber group had good loin eye area (p<0.05), small drip loss (p<0.05), and did not produce PSE pork. For these reasons, a high total muscle fiber number, with a low percentage of type 2b fibers, may be suitable in selecting for improvements in both lean meat production and meat quality.

• Computers and Concrete
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• v.21 no.1
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• pp.1-9
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• 2018

Electrical resistivity is a property associated with both the physical and chemical characteristics of concrete. It allows the evaluation of the greater or lesser difficulty with which aggressive substances penetrate the concrete's core before the dissolution of the passive film process and the consequent reinforcement's corrosion begin. This work addresses the steel fiber addition to concrete with two types and various contents from 0% to 1.3%, correlating it with its electrical resistivity. To that effect, 9 different mixes of steel fiber reinforced concrete (SFRC) were produced. The electrical resistivity was evaluated on the on six years aged SFRC by direct measurement at different frequency from 0.1 kHz to 100 kHz. The results indicate that steel fiber content is strongly conditioned by the type and quantity of the additions used. It was also found that long type of fibers has more effect on decreasing the electrical resistivity of concrete than short fibers. Therefore, they increase the corrosion risk of concrete depending on fiber volume fraction and moisture percentage.