• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.412-418
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• 2009

This study aims to develop a system that enables 20 to 25 wafers to be automatically aligned at the position of the corresponding serial number and facilitates the checkout of wafer processing by sensing them before and after semiconductor processing. It also suggests compensation algorithm and stepper motor control algorithm that carefully align notches. This study minimizes the rate of occurrence by adopting materials of which the surface has proper coefficient of friction when wafers are rotating and that do not rarely produce particles. This study completed the development of a slip resistance apparatus and carried out performance tests through mathematical verification. This system is expected to improve semiconductor yield due to anti-pollution technology in semiconductor processing and can be selectively applied to a large size wafer over 450mm in the future.

• Journal of Korean Society of Steel Construction
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• v.21 no.4
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• pp.433-442
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• 2009

In this paper, new three-dimensional vibration data for the solid cylinders of the N-sided polygonal cross-section with V-notches or sharp cracks are presented, and a Ritz procedure is employed, which incorporates a mathematically complete set of algebraic-trigonometric polynomials in conjunction with an admissible set of edge functions that explicitly model the tri-axial stress singularities that exist along a terminus edge of the V-notch. Convergence studies demonstrate the necessity of adding the edge functions to achieve the accurate frequencies and mode shapes of N-sided polygonal cylindrical solids with stress singularities.

• Journal of Ocean Engineering and Technology
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• v.7 no.2
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• pp.57-67
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• 1993

The fracture behavior of plain woven glass/epoxy composite plates with a crack is investigated under static tensile loading. It is shown in this paper that the characteristic length associated with the point stress criterion depends on the crack length. To predict the not ched tensile strength, the point stress criterion proposed by Whitney and Nuismer are modified. An excellent agreement is found between the experimental results and the analytical prediction of the modified point stress criterion. The condition of unstable crack growth in the presence of a per-existing flaw(machined notch) is examined by means of the maximum stress intensity factor $K_max$ using maximumload P$_max$. The values of $K_max$ evaluated from energy release rate G$_max$(the compliance me thod) indicate a wide difference. Therefore in regard to anisotropy and heterogeneity of the composite materials studied, the modified shape correction factor f(a/W) is obtained. $K_max$evaluated by the compliance method a little or insignificantly depends on the initial crack length a, the specimen thickness B, the crack angle .theta. and the specimen geometry.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.2
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• pp.127-132
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• 1984

In this paper, stress concentration factor and distribution of slotted or notched plate which is subjected to uniaxial tensile load are studied. The experimental measurements have shown the following; (1)The stress around slot or notch of slotted or notched plate which is subjected to uniaxial tensile load is state of biaxial stress, which is mainly varied to notch radius and depth. (2)The stress concentration factor around slot or notch is mainly influenced by the .sigma.$_{yy}$ , it is varied with notch radius and depth. (3)For the notched specimen, there is a notch depth where stress concentration factor is maximum. On the other hand, for the slotted specimen, stress concentration factor increases as the notch depth increases. An investigation of the relationship between fracture and stress concentration factor due to the slot or notch will be presented on the later paper, for reference.

• Korean journal of food and cookery science
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• v.7 no.2
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• pp.75-80
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• 1991

Millet Nochi is a kind of Korean traditional food which is not well known to the general public. This study was crried out in order to elucidate the cooking method and investigate the changes of textural properties during retrogradation. Cooking method for millet Nochi were as follows. 1. Millet is soaked in water for 3 hours, mashed, sifted by 20 mesh 3 screen. 2. The millet flour is mixed with malt (amount of malt is 0.025 times of millet flour by weight) 3. This mixture is steamed for 20 minutes. 4. Steamed mixture is again mixed with the same amount (0.025 times of millet by weight) of malt. 5. The mixture is incubated at $60^{\circ}C$ for 2 hours. 6. After incubation, the mixture is panfried. 7. The changes of textural properties during 30 freeze-thaw cycles, except adhesiveness were not significantly appeared.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.3
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• pp.232-240
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• 1984

The plane elastostatic boundary value problem with the sharp V-notched singularity is formulated by a contour integral method for determining numerically the stress intensity factors. The integral formula is based on Somigliana type of reciprocal work in terms of displacement and traction vectors on the plate boundary. The characteristic singular solutions can be identified on the basis of traction free boundary conditions of two radial notch edges. Two numerical example examples are treated in detail; a symmetric mode-I type of notched plate with various interior angles and a mixed mode type of cantilever subjected to end shear.

• Journal of the Korea Concrete Institute
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• v.16 no.6 s.84
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• pp.851-858
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• 2004

Purpose of this paper is to determine the appropriate size of a center notched disk specimen for mode I fracture toughness $K_{IC}$. For this purpose, mode I test results with various sizes of center notched disk were compared with the RILEM three-point-bend test ones. Compressive strength of concrete used in this paper was 44.9 MPa. Diameters of 200, 300, 400 mm, thickness of 75, 100, 125 mm, and notch length ratios an of 0.3, 0.4, 0.5, 0.6 were used for the mode I disk test. Also, diameter of 300mm thickness of 100mm, and notch length ratios a/R of 0.3, 0.4, 0.5, 0.6 were used for the mixed mode disk test. Mixed mode stress intensity factors were investigated by changing notch angles for the disk specimen. Stress intensity factors of a center notched disk were calculated with the various methods for comparison. From the test results, mode I fracture toughness calculated from the disk specimen with diameter of 300 mm, thickness of Inn and notch length ratio a/R of 0.5 was very similar to the RILEM three-point-bend test ones. And it is verified that stress intensity factors for mixed mode can be easily calculated with the disk specimen.

• Magazine of the Korea Concrete Institute
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• v.2 no.2
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• pp.81-92
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• 1990

Concrete, a mixed material, has heterogeniety, anisotrophy and nonlinearity. Therefore, in its 'racture analysis, it is more reasonable to evaluate its fracture toughness by applying the concept of 'racture mechanics rather than the strength concept. Up to the present the concepts of fracture mechanics which were applied to concrete have been divided into two main classes. The one is the concept of linear elastic fracture mechanics and the other is the concept of elastic-plastic fracture mechanics. But it has been pointed out that there are many problems and irrationalities in applying the concept of linear elastic fracture mechanics to concrete. In this study, the J -integral method and the COD method mainly used in the analysis of nonlinear fracture mechanics, were introduced and the three point bending test was carried out for investigating the effects of the variation of the maximum aggregate size and notch depth on the fracture behavior and the crack growth of concrete, and the relationships of fracture energy and crack opening displacement. According to the results of this study the more the maximum aggregate size and the notch depth increased, the more the nonlinearity of load-deflection behavior was remarkable. The increase of the coarse aggregate size created the more ductility of concrete. Thus concrete showed the more stable fracture. As for the path of the crack growth, the more the coarse aggregate size increased, the more it was irregulary deviated from the straight line but it was not almost affected by the variation of the notch depth. Also, the fracture energy increased according as the coarse aggregate size increased and the notch depth decreased.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.3
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• pp.270-280
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• 2016

This paper investigates the evolution of EM admittance of piezoelectric transducers mounted on a notched beam from wave propagation perspective. A finite element analysis is adopted to obtain numerical solutions for Lamb waves reverberating on the notched beam. The mode-converted Lamb wave signals due to a notch are extracted by using the polarization characteristics of piezoelectric transducers collocated on the beam. Then, a series of temporal spectrums are computed to demonstrate the evolution of EM admittance through fast Fourier transform of the mode-converted Lamb wave signals which are consecutively truncated in the time domain. When truncation time is relatively small, the corresponding temporal spectrum is governed by the characteristics of the input driving frequency. As truncation time becomes large, however, the modal characteristics of the notched beam play a crucial role in the temporal spectrum within the input driving frequency band. This implies that mode-converted Lamb waves reverberating on the beam contributes to the resonance of the beam. The root mean square values are computed for the temporal spectrums in the vicinity of each resonance frequency. The root mean square values increase monotonically with respect to truncation time for any resonance frequencies. Finally the implications of the numerical observation are discussed in the context of damage detection of a beam.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.208-208
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• 2001