• Journal of the Society of Naval Architects of Korea
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• v.50 no.5
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• pp.355-363
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• 2013

Panel methods are essential tools for analyzing a fluid-flow problem around complex three dimensional bodies, but they lack ability to solve viscous effects. On the other hand, CFD methods are considered as powerful tools for analyzing fluid-flow characteristics including viscosity. However, they also have short falls, requiring more computing time and showing different results depending on the selection of turbulence models and grid systems. In this paper a hybrid scheme combining a panel method and a CFD method is suggested. The scheme adopts a panel method for far-field solution where viscous effects are negligible and a CFD method for the solution of RANS equations in near-field where viscous effects are relatively strong. The intermediate region between the far-field and near-field is introduced where the calculated field point velocities by the panel method are given as boundary velocities for the CFD method. To verify the scheme, calculated results, by a panel method, a CFD method and the hybrid scheme, for a two dimensional foil section are compared. The suggested hybrid scheme gives reasonable results, while computation time and memory can be dramatically reduced. By using the hybrid scheme efforts can be concentrated for the local flow near the leading and trailing edges, by providing more dense grid system, where detailed flow characteristics are required.

• Journal of Mechanical Science and Technology
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• v.18 no.2
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• pp.272-285
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• 2004

The losses at off-design points from a compressor cascade occur due to the deviation from a design incidence angle at the inlet of the cascade. The self-noise from the blade cascade at off-design points comes from a separated boundary layer and vortex sheddings. If the incidence angle to the cascade increases, stalling in blades may occur and the noise level increases significantly. This study applied Large-Eddy Simulations (LES) using deductive and deductive dynamic SGS models to low Mach-number, turbulent flow with each incidence angle to the cascade ranging from -40$^{\circ}$ to +20$^{\circ}$ and compared numerical predictions with measured data. It was observed that the oscillating separation bubbles attached to the suction surface do not modify wake flows dynamically for cases of negative incidence angles. However, an incidence angle greater than 8$^{\circ}$ caused a separated vortex near the leading edge to be shed downstream and created stalling. The computed performance parameters such as drag coefficient and total pressure loss coefficient showed good agreement with experimental results. Noise from the cascade of the compressor is summarized as sound generated by a structure interacting with unsteady, turbulent flows. The hybrid method using acoustic analogy was observed to closely predict the measured overall sound powers and directivity patterns at design and off-design points of blade cascade.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.3
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• pp.41-47
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• 2002

Turbulent wake behind a ship propeller has been investigated using the adaptive hybrid 2-frame PTV(Particle Tracking Velocimetry). 400 instantaneous velocity fields were measured according to 4 different blade phases and ensemble-averaged to investigate the spatial evolution of the vortical structure of near wake within one propeller diameter downstream. The phase averaged mean velocity fields show the potential wake and the viscous wake formed by the boundary layers developed on the blade surfaces. As the tip vortex evolves downstream, the slipstream is contracted and the turbulent intensity is decreased with viscous dissipation and turbulent diffusion.

• Fourth Industrial Review
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• v.1 no.1
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• pp.1-10
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• 2021

Purpose - This case study analyzes the internationalization strategy and innovation strategy as key factors contributing to the business success of CAP, a small and medium-sized manufacturing company in Korea producing auto parts such as wipers. This study describes the diversification strategies conducted by CAP Corporation and highlights the company's core competencies that have largely contributed to their global competitive success. Research design, data, and methodology - This paper provides in-depth case study on how CAP was able to grow into a hidden champion company, focusing on their strategies since its establishment. In particular, by analyzing the success factors centering on CAP's aggressive innovation strategy and internationalization strategy, it presents guidelines for small and medium-sized enterprises in Asian countries to become a Hidden Champion company. Result - CAP's product technology has successfully established innovative system on their product called 'vertebra spring' to distribute uniform pressure to the rubber to ensure performance as well as durability of their products. In order to continue benefiting from utilizing core competence and to continue pursuing technological advancement in the wiper industry, CAP has launched a wide range of products (flat blade, conventional blade, hybrid blade) applicable to 95% of the vehicle in the market. Conclusion - Taken together, CAP has many aspects of a hidden champion company by investing in R&D up to 8% of its annual sales to R&D investment even during the crises situation. This number is about 3.36 times higher than the average ratio of listed companies in Korea. Furthermore, the leadership of the management team as well as their vision toward the global market and strong commitment to innovation enabled CAP to become the world's fifth-largest wiper and Asia's No. 1 wiper manufacturer.

• Journal of Korean Society of Forest Science
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• v.43 no.1
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• pp.1-5
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• 1979

The arrangement and the number of vascular bundle in petiole were investigated with the hybrid Populus alba${\times}$P. glandulosa and both parents. 1. The variation in number and the arrangement of the vascular bundle in petiole were smaller at middle point than at nearer point to the leaf blade. 2. A small variation was found in the arrangement of the vascular bundle within a tree, same clone and same species. 3. Five shapes of vascular bundle were recognized in the $F_1$ hybrid, 26.7 per cent of the $F_1$ hybrid has the same shape with P. alba, 13.3 percent with P. glandulosa and 53.3 per cent of the $F_1$ hybrid shows the $F_1$ shape caused by hybridization. 4. The hybrid clones which show the same shape with P. alba are 66-20-1, 66-6-8, 65-22-11 and 64-6-44, hybrid clones of 65-95, 66-14-93 have the same shape with P. glandulosa. Hybrid clones of 66-15-3, 67-6-3, 65-22-4, 66-26-55, 68-1-54, 66-14-99, 65-29-19, 66-25-5 have $F_1$ shape.

• The KSFM Journal of Fluid Machinery
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• v.15 no.2
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• pp.5-11
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• 2012

In this paper, the heat transfer coefficient measurement techniques using TSP(temperature sensitive paint) were introduced and the results of a comparative study on the heat transfer coefficient measurement by steady state and transient TSP techniques were discussed. The distributions of heat transfer coefficient by a single $60^{\circ}$ inclined impingement jet on a flat surface were measured by both techniques. Tested Reynolds number based on the jet diameter (d) was 30,000 and the distance between jet exit and target plate (L) was fixed at 10d. Results showed that the measured Nusselt number by both techniques indicated significant difference except near the center of impingement jet. Also, the heat transfer coefficients measured by the transient TSP technique were affected by the reference temperature of the jet. Based on the measured data, characteristics of both TSP techniques were analyzed and suggestions for applying them were also given.

• Korean Journal of Plant Resources
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• v.33 no.5
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• pp.476-481
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• 2020

In this study, we report a unrecorded plant on the Korean peninsula, Potamogeton × anguillanus Koidz. from Yeondangcheon (stream) in Yeondang-ri, Nam-myeon, Yeongwol-gun, Gangwon-do province. Potamogeton × anguillanus is a natural hybrid between P. wrightii Morong. and P. perfoliatus L. It is distinguished by its characteristic that the petiole is shorter than P. wrightii and that the leaf blade is narrower and longer than P. perfoliatus also, it didn't fully wrap the stem. Considering that P. × anguillanus is a natural hybrid, the name is given to it as 'Eol-chi-gi-dae-ga-rae'. We provide descriptions of the morphological characteristics, photographs, and key to allied taxa in Korea of P. × anguillanus.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.251-256
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• 2007

The aim of this paper is development of resistivity seismic dilatometer (RSDMT) system. The resistivity module for obtaining apparent resistivity depth plot and seismic module for obtaining shear wave velocity (Vs) depth plot are attached to the conventional flat dilatometer testing equipment. From shear wave velocity profile, the stiffness at low strains of a site can be evaluated in undisturbed condition. And the resistivity value contains some information about water content and mineral characteristics of clayey soil. Specially manufactured resistivity and seismic modules were connected between commercialized DMT blade and drilling rod. To enhance reliability and repeatability of RSDMT test, automatic testing system including notebook based data acquisition system and automatic surface source system were developed. RSDMT system can be performed rapidly and can obtaine more reliable data at the same point compared with the separated testing system. The verification studies for the developed RSDMT system are going to be performed. From these studies, the effectiveness of integrated hybrid testing system will be checked in light of proper evaluation of geotechnical design parameters of clayey soils.

• KSBB Journal
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• v.5 no.2
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• pp.175-182
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• 1990

Protoplasts, isolated from leaf of N. tabacum NR-/SR+ and N. glottnosa were electrofused and divided with a plating efficiency of 30∼35% in AAPI 9M medium. Green callus lines were selected in protoplast-derived colonies on MSNO3 selection medium with 1.2mg/ml streptomycin sulfate on the basis of nitrate reductase proficiency and streptomycin resistance. Four putative hybrid plant lines regenerated from the green callus lines had intermediate morphology between that of parents with respect to floral shape, corolla length and ovate leaf blade. Zymograms of leaf peroxidase and esterase from these putative hybrid plant lines showed isozyme profiles derived from both parents and also, they exhibited additional and lost bands. Cytological analysis of two putative hybrid plant lines gave chromosome counts of 2n=66 in L22 and 2n=54 in L44 which were less than the expected number of N. tabacum(2n=48) and N. glutinosa(2n=24).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.379-385
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• 1983

Forage productivity of Job's tears (Coix lachryma-jobi L.) and adlay (C. lachryma-jobi var. mayuen (ROMAN.) STAPF) and a hybrid corn (Kwangog) and sorghum-sudangrass hybrid (Pioneer 988) was compared in the southern part of Korea where black streaked dwarf virus' (BSDV) is prevalent. Emergence of Job's tears and adlay was more delayed compared to a corn or sorghum-sudangrass hybrid under the drought field conditions. Early growth and regrowth of Job's tears and adlay were less than those of sorghum-sudangrass hybrid. Fresh weight, dry weight, and digestible dry matter of Job's tears and adlay cut once approximately 40 days after flowering were much higher than those of two cuts at every flowering stage. Dry weight of one-cut Job's tears and ad lay harvested 40 days after flowering was similar to the total dry weight of three-cut sorghum-sudangrass hybrid but higher than that of silage corn. Digestible dry matter production was greater in the order of sorghum-sudangrass, corn, one-cut and two-cut Job's tears and adlay. Corn was severely infected with BSDV, but digestible dry matter was relatively high due to its higher in vitro dry matter digestibility. Among the Job's tears and adlay varieties, a variety of Job's tears with globular fruit shape was best for forage production due to its taller plant height, thick stem, wider leaf blades, higher leaf blade/total dry weight ratio, and higher forage yield. However, hulled grain yield of ad lay varieties was higher than that of Job's tears due to a higher hulled/rough grain ratio although they had similar rough grain yields.