• Korea-Australia Rheology Journal
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• v.12 no.3_4
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• pp.165-173
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• 2000

Three-dimensional numerical simulation of isothermal/nonisothermal coextrusion process of two immiscible polymers through a rectangular channel has been done using the finite element method. The encapsulation phenomenon with the less viscous layer encapsulating the more viscous layer was investigated with the generalized Newtonian fluids. The interface position around the symmetric plane obtained by numerical simulation nearly coincided with the one observed in experiments, but the degree of encapsulation was less than the one observed experimentally. Open boundary condition method was found to be applied to the simulation of nonisothermal coextrusion process, however, the results are not far from those using the fully developed boundary condition, because the temperature development along the downstream direction is very slow in the case of convection dominated flow. When the inlet velocity is increased, the interface profile does not change in isothermal flow, while it moves upward in nonisothermal situation. The degree of encapsulation decreases along the downstream direction in nonisothermal flow. When the inlet temperature increases compared to the wall temperature, the outlet interface moves downward and the degree of encapsulation increases. The difference of degree of encapsulation between the simulation and the experiments seems to arise from the viscoelastic effect of the materials. It was concluded that the nonisothermal effect alone does not explain the complex coextrusion process and the viscoelastic effect needs to be considered.

• Journal of Life Science
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• v.26 no.5
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• pp.620-631
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• 2016

Viroids are about 250-400 base pair of short single strand RNA fragments have been associated with economically important plant diseases. Due to the lack of protein expression capacity associated with replication, it is very difficult to diagnosis viroid diseases in serological methods. For detecting viroid at plants, molecular-based techniques such as agarose gel electrophoresis, polyacrylamide gel electrophoresis (PAGE), DNA-hybridization, blotting analysis and conventional RT-PCR are reliable. Real-time RT-PCR methods that grafted on RT-PCR methods with improved confirmation methods have been also utilized. However, they are still labor-intensive, time-consuming, and require personnel with expertise. Loop-mediated Isothermal Amplification (LAMP) method is a nucleic acid amplification method under the isothermal condition. The LAMP methodology has been reported to be simple, rapid, sensitive and field applicable in detecting a variety of pathogens. The results of LAMP method can be colorized by adding a visible material such as SYBR green I, Evagreen, Calcein, Berberine and Hydroxy naphthol blue (HNB) with simple equipment or naked eyes. The combination of LAMP method and nucleic pathogens, viroids, can be used to realize simple diagnosis platform for the genetic point-of care testing system. The aim at this review is to summary viroid-caused diseases and the simple visible approach for diagnosing viroids using Loop-mediated Isothermal Amplification (LAMP) method.

• Research in Plant Disease
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• v.21 no.4
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• pp.315-320
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• 2015

Soybean mosaic virus (SMV) is a prevalent pathogen that causes significant yield reduction in soybean production worldwide. SMV belongs to potyvirus and causes typical symptoms such as mild mosaic, mosaic and necrosis. SMV is seed-borne and also transmitted by aphid. Eleven SMV strains, G1 to G7, G5H, G6H, G7H, and G7a were reported in soybean varieties in Korea. A reverse transcription loop-mediated isothermal amplification (RT-LAMP) method allowed one-step detection of gene amplification by simple procedure and needed only a simple incubator for isothermal template. This RT-LAMP method allowed direct detection of RNA from virus-infected plants without thermal cycling and gel electrophoresis. In this study, we designed RT-LAMP primers named SML-F3/B3/FIP/BIP from coat protein gene sequence of SMV. After the reaction of RT-LAMP, products were identified by electrophoresis and with the detective fluorescent dye, SYBR Green I under daylight and UV light. Optimal reaction condition was at $58^{\circ}C$ for 60 min and the primers of RT-LAMP showed the specificity for nine SMV strains tested in this study.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.628-633
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• 2003

An analysis on the steady-state has been made of flow of a compressible fluid rapidly-rotating in a pipe. The flow is induced by an small arbitrary azimuthally-varying thermal forcing added on the basic state of rigid body isothermal rotation. The system Ekman number is assumed to be very small value. Analytic solutions have been obtained for axisymmetric and non-axisymmetric types, in which the axisymmetric solution comes from the azimuthally-averaged wall boundary condition and the non-axisymmetric solution from fluctuating wall boundary condition.

• Tribology and Lubricants
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• v.3 no.1
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• pp.39-46
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• 1987

Frictional loss in turbulent regime is abnormally increased compared with in laminar regime. Thus the consideration of temperature rise across fluid film is significant in analysis and conventional isothermal theory loses its usefulness for performance prediction. This paper proposes to the three-dimensional thermohydrodynamic analysis of finite journal bearings operating under turbulent condition using two-equation model($\kappa-\varepsilon$ model) proposed by Hassid & Poreh. The equations are solved numerically by finite difference method. We make the analysis applicable even at large eccentricity when back flow of the lubricants occurs and axial flow is no longer ignored compared to circumferential flow.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.1
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• pp.207-213
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• 1990

Natural convection heat transfer in rectangular air enclosure was studied interferometrically and numerically for the use of adiabatic and constant temperature horizontal boundary conditions. In the isothermal horizontal boundary case with the temperature difference ratio, .DELTA. $T_{v/}$.DELTA. $T_{H}$ .simeq. 1 temperature distribution in the enclosure is strongly stratified and the average Nusselt Number is higher than that of adiabatic horizontal boundary case.ase.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.673-681
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• 2020

Human enteric Adenovirus 41 (HueAdV-41) is a major waterborne virus that causes human gastroenteritis and is classified as a viral group I double-strand DNA virus, Adenoviridae. HueAdV-41 has been detected with the polymerase chain reaction (PCR) in various samples such as ground water. However, the PCR-based diagnostic method has problems such as reaction time, sensitivity, and specificity. Thus, the loop-mediated isothermal amplification (LAMP) assay has emerged as an excellent method for field applications. In this study, we developed a LAMP system that can rapidly detect HueAdV-41 with high specificity and sensitivity. HueAdV-41 specific LAMP primer sets were tested through a specific, non-specific selection and sensitivity test for three prepared LAMP primer sets, of which only one primer set and optimum reaction temperature were selected. The developed LAMP primer set condition was confirmed as 63℃, and the sensitivity was 1 copy. In addition, to confirm the system, a LAMP positive reaction was developed with the restriction enzyme Taq I (T/GCC). The developed method in this study was more specific, rapid (typically within 2 - 3 hours), and highly sensitive than that of the conventional PCR method. To evaluate and verify the developed LAMP assay, an artificial infection test was done with five cDNAs from groundwater samples, and the results were compared to those of the conventional PCR method. We expect the developed LAMP primer set will be used to diagnose HueAdV-41 from various samples.

• Korean Journal of Materials Research
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• v.11 no.2
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• pp.132-136
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• 2001

Iron- silicide has been produced by mechanical alloying process and consolidated by hot pressing. As-consolidated iron silicides were consisted of $\beta$-FeSi$_2$ phase, and untransformed mixture of $\alpha$-$Fe_2Si_5$ and $\varepsilon$-FeSi phases. Isothermal annealing has been carried out to induce the transformation to a thermoelectric semiconducting $\beta$-$FeSi_2$ phase. The condition for $\beta$-FeSi$_2$ transformation was investigated by utilizing DTA, SEM, TEM and XRD analysis. The phase transformation was shown to be taken place by a vacuum isothermal annealing at $830^{\circ}C$ for 24 hours. The mechanical and thermoelectric properties of $\beta$-FeSi$_2$ materials before and after isothermal annealing were characterized in this study.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.279-284
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• 2023

Isothermal titration calorimetry (ITC) is a useful technique to obtain thermodynamic binding properties such as enthalpy, Gibbs free energy, entropy, and stoichiometry of the chelation reaction. A single independent binding site model was used to evaluate the thermodynamic binding properties in BaCl₂ and ethylenediaminetetraacetic acid (EDTA) in Trince and HEPES buffers. ITC enables us to elucidate the binding mechanism and find an optimal chelation condition for BaCl₂ and EDTA in the pH range of 7~11. Chelation of BaCl₂ and EDTA is a spontaneous endothermic reaction. As pH increased, entropic contributions dominated. The optimal pH range is narrow around pH 9.0, where 1:1 binding between BaCl₂ and EDTA occurs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.10
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• pp.1399-1408
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• 2000

A 2-dimensional temperature field measurement technique using PLIF (Planar Laser Induced Fluorescence) was developed and it was applied to an axisymmetric buoyant jet. Rhodamine B was used as a fluorescent dye. Laser light sheet illuminated a two-dimensional cross section of the jet. The intensity variations of LIF signal from Rhodamine B molecules scattered by the laser light were captured with an optical filter and a CCD camera. The spatial variations of temperature field of buoyant jet were derived using the calibration data between the LIF signal and real temperature. The measured results show that the turbulent jet is more efficient in mixing compared to the transition and laminar jet flows. As the initial flow condition varies from laminar to turbulent flow, the entrainment from ambient fluid increases and temperature decay along the jet center axis becomes larger. In addition to the mean temperature field, the spatial distributions of temperature fluctuations were measured by the PLIF technique and the result shows the shear layer development from the jet nozzle exit.