• Journal of KSNVE
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• v.7 no.2
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• pp.255-260
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• 1997

This paper describes 3-dimensional volume array of 4 microphones including a reference microphone which is capable of imaging wideband noise source position in 2-dimensional image plane. The cross correlation function and corresponding imaging function between a reference microphone and other microphone, are derived as a function of noise source position. The magnitude of the imaging function gives noise source mapping in image plane. Since the image plane is selective from a rectangular and a cylindrical plane, noise source position information such as range and bearing relative to the array is identified very much easily. Simulation results for typical source configurations confirms the applicability of the proposed array in noise control field.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1858-1864
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• 2016

Morphological and molecular information of two marine algae collected from Korea is given. One belonging to a green alga, is characterized by small size up to 4 cm high, much branched thalli on all sides, slender and linear branchlets which is constricted near base, axes without prominent branch scars, chloroplasts with a prominent central pyrenoid. The other, as a brown alga, is distinct from other Korean species in having cylindrical elevated projections at all parts of thallus axis, leaves with slightly serrulate margin together with distinct midrib bearing spines and absence to rarely occurred vesicles. In phylogenetic tree based on rbcL sequences, these two species are nested in the same clade with Bryopsis triploramosa and Sargassum polyporum, respectively. In this study, these two species are newly recorded in the Korean marine algal flora based on the morphological and molecular data.

• Journal of the Korean Geosynthetics Society
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• v.9 no.2
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• pp.33-40
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• 2010

In this study, the pullout tests are conducted to evaluate pullout resistance of steel strip reinforcement with transverse members. The test results are compared with theoretical equations and then the failure mechanism of transverse members is evaluated. The bearing resistance stress(${\sigma}^{\prime}_b$) of transverse members, which is applied pullout force at 50mm displacement, is closed from punching shear failure to general shear failure. The behavior by increment of a number of transverse members became closer to general shear failure. The behavior of transverse members at maximum pullout force, which is closed to general shear failure, is indicated that it is unrelated to normal stress and a number of transverse members. However, if the allowable displacement of reinforced soil wall is considered, it is impossible to apply in design. The test results are compared with bearing resistance evaluations using Prandtl's plastic theory and cylindrical cavity expansion theory. The analysis results are indicated that the bearing resistance by pullout tests is closed to predicted result by Prandtl's plastic theory, which are located between general shear failure and punching shear failure.

• Tribology and Lubricants
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• v.26 no.5
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• pp.263-271
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• 2010

The rollers of cylindrical roller bearing are axially profiled to relieve high edge stress concentration caused by mainly their finite length and by misalignment. In this paper, a numerical analysis is carried to study the EHL of misaligned (tilted) rollers with axially profiled ends. Using a finite difference method with non-uniform grids and the Newton-Raphson method, the highly nonlinear EHL problems are systematically solved. Physically consistent solutions are obtained for moderate load, material parameters and very small misalignment. For different misalignment angles, contours and sectional plots of pressure and film shape near both edge regions are compared. The asymmetric pressure distributions and film shapes show that the EHL results of finite line contacts are highly dependent upon very small amounts of roller misalignment. Especially, the effect of misalignment on the EHL pressure distribution is much higher than the film shapes.

• Mycobiology
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• v.42 no.4
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• pp.317-321
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• 2014

Fruiting bodies similar to those of the ascomycete fungi Podostroma cornu-damae and Cordyceps militaris were collected from Mt. Seunghak in Busan, Korea on August 21, 2012. The fruiting bodies were cylindrical, with tapered ends and golden red in color. The fruiting bodies contained abundant conidiophores bearing single-celled conidia, but no perithecia or asci. Pure culture of the fungal isolates was obtained through single-spore isolation. Analyses of morphological characteristics, including conidia shape, and phylogenetic traits, using internal transcribed spacer sequences, showed that these isolates belonged to the species Simplicillium lanosoniveum. Although this fungal species is known to be mycoparasitic, the isolates obtained in this study were unable to infect fungi. However, silkworms (Bombyx mori) inoculated with the fungal isolates died during the larval or pupal stages, as has been shown for the strongly entomopathogenic fungus Beauveria bassiana. This study is the first report of the entomopathogenicity of S. lanosoniveum and indicates its potential for use in biological control of insects.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1750-1756
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• 2009

In this paper, 5 kWh class Superconductor Flywheel Energy Storage System (SFES) was constructed including motor/generator, superconductor magnetic bearing(SMB), composite rotor and electromagnetic damper(EMD) system. High speed rotation test was performed after levitating flywheel rotor only using EMD without SMB. the PD controller of EMD was designed. the control system is constructed using xPC which is real time digital control system. the results of high speed rotation test showed that proposed EMD system have sufficient damping in cylindrical mode and conical mode, and vibration of wheel was suppressed below 10 ${\mu}m$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.581-586
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• 2018

Cast iron manhole lids cause environmental pollution during the manufacturing process, and the work environment is very poor. In addition, if the height of the manhole cover does not match the height of the road surface, it causes considerable inconvenience and safety problems. This study proposes a height - adjustable steel manhole cover that can replace cast iron manhole covers and easily match the road surface with the upper surface of the manhole cover. Structural analysis was performed to grasp the design variable of the structure of the manhole cover, satisfying the required quality performance. To fabricate a manhole cover that satisfies the required load capacity, the optimal design for the U-shaped reinforcement structure was made. The cylindrical shape of the height adjustment part and the low frame were formed by bending the steel sheet into a circular shape and then welding. Reinforcing bars were also made by bending a steel plate. The height adjustment groove was machined by a CNC milling machine. Four prototypes were fabricated and a load bearing test was carried out, and new manhole cover was made reflecting results of the test. In the load bearing test, there was no breakage of the welded part, and deformation occurred mainly at the contact area between the groove and gusset plate. Deformation of 1 to 2.7mm occurred due to a load of 450kN. On the other hand, after removing the load, there was almost no residual deformation, and the load bearing evaluation was judged to be satisfactory because the manhole cover could be disassembled and reassembled.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.1
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• pp.107-114
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• 2014

A friction hinge system which moves without power was designed and developed using the principle of friction force, which is caused by interference between the inner diameter of a silicon cap and the outer diameter of a cylindrical roller bearing with one-way rotation in a counterclockwise direction. The system was applied to the lid of buffet ware, which moved up by external force and moved down by gravitational force. However, design conditions which included a rotation angle of the hinge of more than 80 degrees and a closing time of more than 20 seconds were required when the lid of the buffet ware closed due to gravitational force. The design safety of the friction hinge body connected to the lid of the buffet ware from the hinge system was checked on the basis of structural, fatigue and thermal analyses. The material of the shaft, cap and flange among the hinge elements was changed to polyethylene from steel to reduce the weight of the friction hinge system. An injection molding simulation was performed and injection molds of the shaft, cap and flange were created. The weight of the hinge system was decreased from 805g to 219g.

• Mycobiology
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• v.40 no.1
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• pp.79-81
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• 2012

Cankers are localized dead areas in the bark of stems, branches or twigs of many types of trees and shrubs, and are usually caused by fungi. We observed severe canker symptoms in oak trees located in Gyeongnam province in 2011. A total 31 trees were discovered with cankers of varied size, with an average of $48.5{\times}15.2cm$. Black, half-rounded globular mound shaped stromata were associated with the cankers, and the asci of the fungi associated with the cankers were cylindrical shaped with their spore-bearing parts being up to 84 ${\mu}m$ in length. The average fungal ascospores size was $7.59{\times}4.23{\mu}m$. The internal transcribed spacer sequence for the canker causing fungus showed 99% similarity to the sequence of $Annulohypoxylon$ $truncatum$. In this study, the isolated fungus was precisely described and then compared with fungi of similar taxa.

• Steel and Composite Structures
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• v.19 no.3
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• pp.661-678
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• 2015

Buckling Restrained Braces (BRB) have been widely used in the construction industry as they utilize the most desirable properties of both constituent materials, i.e., steel and concrete. They present excellent structural qualities such as high load bearing capacity, ductility, energy-absorption capability and good structural fire behaviour. The effects of size and type of filler material in the existed gap at the steel core-concrete interface as well as the element's cross sectional shape, on BRB's fire resistance capacity was investigated in this paper. A nonlinear sequentially-coupled thermal-stress three-dimensional model was presented and validated by experimental results. Variation of the samples was described by three groups containing, the steel cores with the same cross section areas and equal yield strength but different materials (metal and concrete) and sizes for the gap. Responses in terms of temperature distribution, critical temperature, heating elapsed time and contraction level of BRB element were examined. The study showed that the superior fire performance of BRB was obtained by altering the filler material in the gap from metal to concrete as well as by increasing the size of the gap. Also, cylindrical BRB performed better under fire conditions compared to the rectangular cross section.