• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.260-261
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• 2002

For Near-field Scanning Optical Microscopy measurements, the fiber tip is glued on the side of one of the tuning fork prongs vertically to its extended direction. Higher Q-factor is attainable in this geometry than in the arrangement with the fiber tip parallel to the prong. A simple mechanical design is applied to hold the fiber tip above the gluing point. The overall tuning fork-fiber tip assembly gives another advantage of the flexible Q-factor enhancement. With this treatment, Q-factor higher than 3000 is easily achievable. As an operating instance, a grating is scanned for its one dimensional topographical image.

• Journal of the Korea Concrete Institute
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• v.26 no.3
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• pp.307-313
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• 2014

In order to predict the post-cracking tensile behavior of fiber reinforced concrete, it is necessary to evaluate the fiber orientation factor which indicates the number of fibers bridging a crack. For investigation of fiber orientation factor on a circular cross-section, in this paper, cylindrical steel fiber reinforced concrete specimens were casted with the variables of concrete compressive strength, circular cross-section size, fiber type, and fiber volumetric ratio. The specimens were cut perpendicularly to the casting direction so that the fiber orientation factor could be evaluated through counting the number of fibers on the circular cross-section. From the test results, it was investigated that the fiber orientation factor on a circular cross-section was lower than 0.5 generally adopted, as fibers tended to be perpendicular to the casting direction. In addition, it was observed that the fiber orientation factor decreased with an increase of the number of fibers per unit cross-section area. For rational prediction of the fiber orientation factor on a circular section, a rigorous model and a simplified equation were derived through taking account of a possible fiber inclination angle considering the circular boundary surface. From the comparison of the measured data and the predicted values, it was found that the fiber orientation factor was well predicted by the proposed model. The test results and the proposed model can be useful for researches on structural behavior of steel fiber reinforced columns with a circular cross-section.

• Computers and Concrete
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• v.30 no.5
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• pp.323-337
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• 2022

This paper proposes a numerical model to simulate the rotational behavior of steel fiber in fresh cement-based materials in the presence of a magnetic field. The results indicate that as the aspect ratio of fiber increases, the required minimum magnetic field intensity to make fiber rotate in viscous fluid increases. The optimal magnetic field intensity is 0.03 T for aligning steel fiber in fresh cement-based materials to ensure that the applying time of the magnetic field can be conducted concurrently with the vibrating process to increase the aligning efficiency. The orientation factor of steel fiber in cement mortar can exceed 0.85 after aligning by 0.03 T of the uniform magnetic field. When the initial angle of the fiber to the magnetic field direction is less than 10°, the magnetic field less than 0.03 T cannot make the fiber overcome the yield stress of fluid to rotate. The coarse aggregate in steel fiber-reinforced concrete is detrimental to the rotation and alignment of the steel fiber. But the orientation factor of ASFRC under the 0.03T of the magnetic field can also exceed 0.8, while the orientation factor of SFRC without magnetic field application is around 0.6.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.251-254
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• 2005

This study will have to define the shear strengthening effects of steel fiber in beam and column levels, as well as to suggest estimation method of maximum shear capacity of structural members. From review of literature surveys and perform structural member test results, following conclusion can be made; In beam level, steel fiber strengthening factor is suggested from the tensile splitting test results and beam test results. After suggesting shear capacity of beam without stirrups and beam with stirrups by proposed steel fiber strengthening factor, proposed equation is possible to evaluate the shear capacity of beam. In column level, with column test results and proposed steel fiber strengthening factor, shear capacity equation of steel fiber reinforced concrete in column is suggested.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.2
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• pp.213-220
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• 2004

The purpose of this study is to evaluate the shear strength of SFRC beam that has no stirrups by steel fiber strengthening factor. To achieve the goal of this study, two stage investigation, which is material and member level, is studied with literature and experimental side. From the reviewing of previous researches and analyzing of material and member test results, strengthening parameter of SFRC is defined as steel fiber coefficient. Based on above results, steel fiber strengthening factor is proposed. And by reviewing the proposed equation of shear strength estimation, equation of Shin was well estimated the shear strength of SFRC beams. Therefore, shear strength equation of SFRC, which is composed by Shin's Eq. and steel fiber strengthening factor, is proposed by regression analysis of test results.

• Korean Journal of Human Ecology
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• v.19 no.2
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• pp.389-398
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• 2010

This study examines the relationship between the concern about well-being lifestyle and the perceived image of Hanji fiber. A survey was conducted among male and female consumers aged 20 and over in Jeonju and Daejon from January 4th to 11th, 2008. A total of 168 responses were analyzed by using descriptive statistics, factor analysis, and ANOVA via the SPSS ver. 12. As a result, four factors were determined in the concern for a well-being lifestyle; product consumption, enjoying culture, using therapy and managing the household. The perceived image of Hanji fiber were classified into four elements; traditional, high-quality, functional and popular images. Among the factors of the concern for a well-being lifestyle and the perceived image of Hanji fibers, a partial relationship was observed. There is a positive relationship, especially between the product consumption factor of a well-being lifestyle and the high-quality and functional image of Hanji fiber. Also, there was a positive relationship between the factor of managing the household and the traditional image of Hanji fiber. However, the therapy interest factor of a well-being lifestyle was negatively related to the traditional image of Hanji fiber.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.6
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• pp.15-20
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• 1998

The linewidth enhancement factor $\alpha$ and fiber dispersion of 1.55 ${\mu}{\textrm}{m}$ strained multi-quantum well laser diodes are measured using small signal power modulation transfer function in a dispersive fiber. The measured fiber dispersion values are between 16.766 and 16.786ps/nm/km and these are the expected values from standard single mode fiber. To measure the $\alpha$ parameter in the actual operational range of the laser diodes, the dependence of $\alpha$ on laser output power is measured. The $\alpha$ parameter increases linearly as the power of the laser diode increases. This result can explain the non-linear gain effect on the $\alpha$ parameter more accurately than any other measurements.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.4
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• pp.73-78
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• 2004

The conventional SLT(Shear Lag Theory) which has been proven that it can not provide sufficiently accurate strengthening predictions in elastic regime when the fiber aspect ratio is small. This paper is an extented work to improve it by modifying the load transfer mechanism called NSLT(New Shear Lag Theory), which takes into account the stress transfer across the fiber ends and the SCF(Stress Concentration Factor) that exists in the matrix regions near the fiber ends. The key point of the model development is to determine the major controlling factor among the material and geometrical coefficients. It is found that the most affecting factor is the fiber/matrix elastic modulus ratio. It is also found that the proposed model gives a good result that has the capability to correctly predict the elastic properties such as interfacial shear stresses and local stress variations in the small fiber aspect ratio regime.

• Environmental Engineering Research
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• v.25 no.3
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• pp.439-445
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• 2020

In the estimation of the aerosol single fiber efficiency using fibrous filters, there is a size range, where the particles penetrate most effectively through the fibrous collectors, and corresponding minimum single fiber efficiency. For small particles in which the diffusion mechanism is dominant, the Cunningham slip correction factor (C_c) affects the single fiber efficiency and the most penetrating particle size (MPPS). Therefore, for accurate estimation, C_c is essential to be considered. However, many previous studies have neglected this factor because of its complexity and the associated difficulty in deriving the appropriate parameterization particularly for the MPPS. In this study, the expression for the MPPS, and the corresponding expression for the minimum single fiber efficiency are analytically derived, and the effects of C_c are determined. In order to accommodate the slip factor for all particle-size ranges, C_c is simplified and modified. Overall, the obtained analytical expression for the MPPS is in a good agreement with the exact solution.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.474-482
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• 2002

The purpose of the study is to establish an optimum geometry and optimum geometry factor through bond test of a structural synthetic fiber, which fully utilizes matrix anchoring without fiber fracturing with the maximum pullout resistance. Seven deformed structural synthetic fibers with widely different geometries were investigated and pullout test was conducted. Included parameters are seven different types of fiber and two of mortar matrixes. The test result shows that the crimped type structural synthetic fiber is significant improvement in the interface toughness(pullout energy) and pullout load. The pullout test was performed with various size of crimped type structural synthetic fiber in order to invest optimum geometry factor, In the basis of the test results, optimum geometry factor is established such as D=b$^{{\alpha}0{\alpha}}$h$^{λ{\beta}}$.