• Journal of the Korean Society of Visualization
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• v.11 no.2
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• pp.12-17
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• 2013

A flow visualization technique was developed to analyze flow distribution inside a dishwasher in this study. Then, a new design plan was proposed to improve the efficiency of the dishwasher by the analyzed results and it was confirmed experimentally by the developed technique. Gas flow fields inside a drying duct of a tub for a drying process was investigated by a developed PIV (Particle Image Velocimetry) and a CFD (Computational Fluid Dynamics) method. Also, the flow visualization technique was developed for the liquid flow field of a rotor-arm system to propose the improved design idea. Also, interactions between liquid and gas were observed around the rotor-arm system. The two-phase flow was modified to the liquid flow field because laser sheets are refracted when pass through the two-phase flow. Thus, the flow visualization techniques was developed in this study to measure the instantaneous flow velocities in the liquid quantitatively.

• Journal of the Korean housing association
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• v.19 no.1
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• pp.79-88
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• 2008

Hot water is used by having a wash, dishes, taking tub and drinking water in residential buildings, and the use objective is to raise comfort of human body sense, washing and sterilization effect and so on. Cold & hot water supply system is understanded simpler than HVAC systems relatively, so it is true that pace of performance improvement is slower than other systems for plan and technical development. In this study, the performance evaluations are conducted under the condition of composition ratio by 1:1 for cold & hot water supply manifold system using functionally complex valves such as constant flow regulating valve and 3-way mixing valve in the area of $105.6m^2$ apartment which consist of the largest part of the whole apartment. Also, flow rate related to simultaneous use of faucets and change of hot water temperature are compared with the existing method.

• Geotechnical Engineering
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• v.3 no.3
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• pp.49-62
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• 1987

The settling behavior of marine fluid mud in the west seaside of Korea has been studied with theoretical analysis and experimental technique. This paper describes laboratorial experiments on the sedimentation and the deposition of soil particles in seawater, with measurement of velocity of interface, the water contents, the settlement. And the reseults are compared with an earlier theoretical research, the hindered settling theory of Kynch, McRoberts and Nixon. According to the results the process of Banweol mud sedimentation showed the typical mode of the hindered settling under the condition of initial water content, wo=1000%. Also, the falling rates of fluid mud interface from initial settling height vs. the rising rates of soil deposit from the bottom of the test tub were measured by the function of time, the correlati tranship of them demonstrated as a straight line and obtained an experimental formula.

• Computers and Concrete
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• v.4 no.5
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• pp.403-424
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• 2007

The investigation of corrosion effects on the tensile behavior of reinforced concrete (RC) members is very important in region prone to high corrosion conditions. In this article, an experimental study concerning corrosion effects on tensile behavior of RC members is presented. For this purpose, a comprehensive experimental program including 58 cylindrical reinforced concrete specimens under various levels of corrosion is conducted. Some of the specimens (44) are located in large tub containing water and salt (5% salt solution); an electrical supplier has been utilized for the accelerated corrosion program. Afterwards, the tensile behavior of the specimens was studied by means of the direct tension tests. For each specimen, the tension stiffening curve is plotted, and their behavior at various load levels is investigated. Average crack spacing, loss of cross-section area due to corrosion, the concrete contribution to the tensile response for different strain levels, and maximum bond stress developed at each corrosion level are studied, and their appropriate relationships are proposed. The main parameters considered in this investigation are: degree of corrosion ($C_w$), reinforcement diameter (d), reinforcement ratio (${\rho}$), clear concrete cover (c), ratio of clear concrete cover to rebar diameter (c/d), and ratio of rebar diameter to reinforcement percentage ($d/{\rho}$).

• Food Science and Preservation
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• v.14 no.6
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• pp.688-694
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• 2007

To evaluate the human risk of long-term intake of genetically modified (GM) rice, we carried out RT-PCR of housekeeping genes. Housekeeping genes, which show highly uniform expression in living organisms during various stages of development and under different environmental conditions, were normalized by RT-PCR. We assessed the expression of 10 common housekeeping genes (18s rRNA, 25S rRNA, UBC, UBQ5, UBQ10, ACT11, GAPDH, eEF-$1{\alpha}$, ${\beta}$-TUB, GAPDH, ${\beta}$-actin, B2m, G6pd2, Gyk, Gus, Hprt, Cyclophlin A, Tfrc, ${\alpha}$-tubulin and RPL13A) in the liver, stomach, small intestine, large intestine, kidney and spleen of mice fed GM or non-GM rice. We found no significant differences in the expression of housekeeping genes between the two groups of mice.

• Journal of the Korea Safety Management & Science
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• v.13 no.1
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• pp.195-202
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• 2011

The study interprets each of three classification models based on Bath-Tub Failure Rate (BTFR), Extreme Value Distribution (EVD) and Conjugate Bayesian Distribution (CBD). The classification model based on BTFR is analyzed by three failure patterns of decreasing, constant, or increasing which utilize systematic management strategies for reliability of time. Distribution model based on BTFR is identified using individual factors for each of three corresponding cases. First, in case of using shape parameter, the distribution based on BTFR is analyzed with a factor of component or part number. In case of using scale parameter, the distribution model based on BTFR is analyzed with a factor of time precision. Meanwhile, in case of using location parameter, the distribution model based on BTFR is analyzed with a factor of guarantee time. The classification model based on EVD is assorted into long-tailed distribution, medium-tailed distribution, and short-tailed distribution by the length of right-tail in distribution, and depended on asymptotic reliability property which signifies skewness and kurtosis of distribution curve. Furthermore, the classification model based on CBD is relied upon conjugate distribution relations between prior function, likelihood function and posterior function for dimension reduction and easy tractability under the occasion of Bayesian posterior updating.

• The Korean Journal of Mycology
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• v.48 no.2
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• pp.103-116
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• 2020

Freshwater ecosystems provide a complex environment for microorganisms. In this study, we isolated diverse fungal strains from plant litter in freshwaters. These strains were identified using molecular phylogenetic analyses of rDNA and/or other gene sequences (TUB, GAPDH, and EF1). In addition, we examined their morphological characteristics by microscopy and cultural characteristics on several media. We identified six previously unrecorded Sordariomycetes species in Korea, i.e., Colletotrichum godetiae, Discosia rubi, Robillarda sessilis, Monochaetia dimorphospora, Idriella lunata, and Phialemoniopsis endophytica. Of these, D. rubi and M. dimorphospora exhibited high extracellular amylase, lipase, and protease activities, suggesting that these fungal isolates might play an important role as decomposers in freshwater ecosystems. Plant litter could thus be a good source for isolating and investigating previously undocumented fungal species in freshwater environments.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.155-165
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• 1998

The resistance coefficient and heat transfer performance are studied for the turbulent water flow in a smooth coiled tube having variable curvature ratios and a corrugated-coiled tube having a ratio of coil to tube diameter of 22. Experiments are carried out for the fully developed turbulent flow of water in tube coils on the uniform wall temperature condition. This work is limited to tube coils of R/a between 22 and 60 and Reynolds numbers from 13000 to 53000. The tube having a ratio of coil to tube diameter of 27 among the 3 smooth tube coils shows the best heat transfer performance. A corrugated-coiled tube(R/a=60) shows more excellent performance than a smooth coiled tub (R/a=60) at a similar curvature ratio. The friction factor f is sensitive to changes in the velocity profile caused by a temperature gradient. Allowance was made for the pressure loss in the short inlet and outlet lengths and due to the presence of the thermocouple inlet and outlet as a result of separate experimental on a straight tube. It is to be expected that the allowance at the exit will be somewhat too low because of secondary flow effects carried over from the coil.

• Mycobiology
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• v.48 no.5
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• pp.341-350
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• 2020

Three fungal strains belonging to the class Sordariomycetes were isolated from soils collected from Gyeongsangbuk-do in Korea. They were identified as Cephalotrichum hinnuleum (UD CT 1-3-3 and KNU-19GWF1) and Thelonectria chlamydospora sp. nov. (UD ST 1-2-1). T. chlamydospora sp. nov. was morphologically identical to T. truncata, but its specific macroconidial dimensions, lower number of septations, and chlamydospore diameter render it distinct from the strains of the genus Thelonectria. The strains UD CT 1-3-3 and KNU-19GWF1 were developed flat, velvety to felty, and golden gray to brown-gray after 14 days of incubation at 25 ℃ on PDA. These strains were produced polyblastic conidiogenous cells and conidia were pale brown to brown, smooth, thin-walled, subglobose to ellipsoidal, arranged in chains, and the diameters of 6.7-9.0 × 3.7-5.1 ㎛. The strains were also confirmed by using the multi-locus genes using internal transcribed spacer (ITS) regions, partial large subunit (LSU), translation elongation factor 1α (TEF1-α), β-tubulin (TUB2), and actin (ACT) genes. This is the discovery of T. chlamydospora sp. nov. and Cephalotrichum hinnuleum, a new record from Korea.

• The Korean Journal of Mycology
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• v.49 no.4
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• pp.477-486
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• 2021

A survey of insect-associated fungi in Korea revealed a novel fungal strain isolated from the bean bug Riptortus clavatus (Heteroptera: Alydidae). Culturally and morphologically, the fungal strain designated KNUF-20-INY03, shares features with members of the genus Acaulium. Phylogenetic analyses based on the concatenated nucleotide sequences of the internal transcribed spacer regions (ITS) regions and partial sequences of the translation elongation factor 1-alpha (TEF1-α), and β-tubulin (β-TUB), and large subunit of the nuclear ribosomal RNA (LSU) genes showed that the isolate is part of a clade that includes other Acaulium species, but it occupies a distinct phylogenetic position. Based on the shape, size, and color of its conidia and conidiogenous cells, strain KNUF-20-INY03 is readily distinguishable from the closely related A. acremonium, A. albonigrescens, A. caviariformis, A. pannemaniae, and A. retardatum. The conidial length-to-width ratio (1.6) of the novel isolate is significantly lower than that of A. acremonium (1.9), A. albonigrescens (2.4), and A. pannemaniae (2.4), and KNUF-20-INY03 produces hyaline conidia and elliptical conidiogenous cells while A. caviariformis forms brown conidia and A. retardatum produces flask-shaped conidiogenous cells. Thus, both phylogenetic and morphological analyses indicate that this strain is a novel species in the genus Acaulium, and we propose the name Acaulium microspora sp. nov.