• Korean Journal of Materials Research
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• v.11 no.6
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• pp.483-491
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• 2001

The recovery and recrystallization behavior of cold-rolled Zr-based alloys during isothermal annealing at temperatures from $575^{\circ}C$ to $650^{\circ}C$ was studied by thermoelectric power and Vickers microhardness measurement. The recovery and recrystallization resulted in the increase of TEP doe to the extinction of lattice defect, vacancy, dislocation and stacking fault during isothermal annealing after cold- rolling. The completion of recrystallization could be determined much clearly by TEP behavior than by microhardness change in Zr-based alloys. Especially, the recovery and recrystallization were classified separately by TEP behavior in Zr-0.4Nb-xSn alloys. From the analysis of TEP behavior and microhardness, the addition of Sn caused to form the interaction between stain field and dislocation, which resulted in the delay of recovery in Zr-based alloys. The precipitation due the addition of Nb suppressed the grain growth after recrystallization effectively in Zr-based alloys.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.1-6
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• 2013

Tetanus is a specific infectious disease, which is often associated with catastrophic events such as earthquakes, traumas, and war wounds. The obligate anaerobe Clostridium tetani is the pathogen that causes tetanus. Once the infection of tetanus progresses to an advanced stage within the wounds of limbs, the rates of amputation and mortality increase manifold. Therefore, it is necessary to devise a rapid and sensitive point-of-care detection method for C. tetani so as to ensure an early diagnosis and clinical treatment of tetanus. In this study, we developed a detection method for C. tetani using loop-mediated isothermal amplification (LAMP) assay, wherein the C. tetani tetanus toxin gene was used as the target gene. The method was highly specific and sensitive, with a detection limit of 10 colony forming units (CFU)/ml, and allowed quantitative analysis. While detecting C. tetani in clinical samples, it was found that the LAMP results completely agreed with those of the traditional API 20A anaerobic bacteria identification test. As compared with the traditional API test and PCR assay, LAMP detection of C. tetani is simple and rapid, and the results can be identified through naked-eye observation. Therefore, it is an ideal and rapid point-of-care testing method for tetanus.

• 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.

• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1672-1683
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• 2021

Vibrio parahaemolyticus is recognized as one of the most important foodborne pathogens responsible for gastroenteritis in humans. The bla_CARB-17 gene is an intrinsic β-lactamase gene and a novel species-specific genetic marker of V. parahaemolyticus. In this study, a loop-mediated isothermal amplification (LAMP) assay combined with a lateral flow dipstick (LFD) was developed targeting this bla_CARB-17 gene. The specificity of LAMP-LFD was ascertained by detecting V. parahaemolyticus ATCC 17802 and seven other non-V. parahaemolyticus strains. Finally, the practicability of LAMP-LFD was confirmed by detection with V. parahaemolyticus-contaminated samples and natural food samples. The results showed that the optimized reaction parameters of LAMP are as follows: 2.4 mmol/l Mg²⁺, 0.96 mmol/l dNTPs, 4.8 U Bst DNA polymerase, and an 8:1 ratio of inner primer to outer primer, at 63℃ for 40 min. The optimized reaction time of the LFD assay is 60 min. Cross-reactivity analysis with the seven non-V. parahaemolyticus strains showed that LAMP-LFD was exclusively specific for V. parahaemolyticus. The detection limit of LAMP-LFD for V. parahaemolyticus genomic DNA was 2.1 × 10^-4 ng/μl, corresponding to 630 fg/reaction and displaying a sensitivity that is 100-fold higher than that of conventional PCR. LAMP-LFD in a spiking study revealed a detection limit of approximately 6 CFU/ml, which was similar with conventional PCR. The developed LAMP-LFD specifically identified the 10 V. parahaemolyticus isolates from 30 seafood samples, suggesting that this LAMP-LFD may be a suitable diagnostic method for detecting V. parahaemolyticus in aquatic foods.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.89.2-89.2
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• 2012

We present our analysis of a newly discovered galaxy-galaxy gravitational lens system in the First Look Survey (FLS) field. This object shows a highly distorted background galaxy (z=0.245) image by a nearby elliptical galaxy (z=0.08), which can be interpreted as a result of gravitational lensing. We model the lens with elliptical isothermal sphere model, and present the mass and potential distribution of the system.

• Korea-Australia Rheology Journal
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• v.12 no.2
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• pp.101-105
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• 2000

The crystallization behavior of homo polypropylene (PP) and PP in the PP-poly($\varepsilon$-caprolactone) (PCL) blends during isothermal crystallization has been investigated using differential scanning calorimeter (DSC) and advanced rheometric expansion system (ARES). From the storage modulus data of the homo PP and PP-PCL blends during isothermal crystallization, the volume fraction of crystallized material ($X_t$) of the homo PP and PP in the PP-PCL blends was calculated using the various rheological models. The results of $X_t$ of the homo PP and PP in the PP-PCL blends from ARES measurement were compared with the results from DSC. The $X_t$ of the homo PP was found to be higher in the ARES measurement than in the DSC. The crystallization rate of the homo PP was found to be faster in the rheological measurements than in the thermal analysis. The $X_t$ of PP in the PP-PCL blends with various compositions was obtained from the thermal analysis and rheological measurements. The $X_t$ of PP in the PP-PCL blends obtained from the thermal analysis and rheological measurements are not consistent. This discrepancy of $X_t$ may be due to the morphological changes resulted from the different crystallization kinetics of PP in the PP-PCL blends.

• Polymer(Korea)
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• v.33 no.5
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• pp.435-440
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• 2009

Thermal degradation behavior of CR (chloroprene) -modified NR (natural rubber) compounds, having different sulfur/accelerator compositions, was studied by non-isothermal TGA method. Data were analyzed using both Kissinger and Flynn-Wall-Ozawa analysis to assess the activation energies. Activation energy obtained from Kissinger analysis was $147.0{\pm}2.0$ kJ/mol for all samples, showing little effect of sulfur/accelerator composition changes in the samples. On the other hand, activation energy from Flynn-Wall-Ozawa analysis exhibited much variations with conversion, showing average value of $211.6{\pm}19.0$ kJ/mol. From the results, it was considered that whole thermal degradation processes of the samples were composed of complex multiple step processes, of which reaction mechanisms were different from each other.

• Food Science of Animal Resources
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• v.33 no.5
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• pp.610-616
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• 2013

Loop-mediated isothermal amplification (LAMP) is an emerging detection technology for the amplification of DNA under isothermal conditions. The aim of this study was to develop a rapid and reliable LAMP technique for the detection of Cronobacter sakazakii in milk powder. In order to enhance the sensitivity and specificity, LAMP primers targeting outer membrane protein A (ompA) gene of C. sakazakii were designed using Explorer V4 software. Thirty seven C. sakazakii strains and 13 pathogenic microorganisms were used for comparative detection of C. sakazakii using polymerase chain reaction (PCR), real-time PCR, and LAMP. LAMP developed in this study could specifically detect C. sakazakii strains without cross-reactivity with other foodborne pathogens. LAMP products amplified from ompA gene of C. sakazakii were digested with with HhaI and NruI enzyme. The specificity of LAMP was confirmed by restriction fragment length polymorphism (RFLP) analysis. LAMP could detect C. sakazakii within 1 h without bacterial culture and its detection limit was as low as 1 CFU/mL C. sakazakii in milk. In the comparison of the sensitivity, LAMP showed 10,000- and 100-times higher detection limit than PCR or real-time PCR, respectively. Therefore, this study can conclude that LAMP is a rapid and reliable detection technique for C. sakazakii contaminated in powdered milk.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.692-699
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• 2013

In this study, isothermal (350, 375, 400, 425, 450, 500, $850^{\circ}C$) experiments were carried out using a custom-made thermobalance to analyze the thermal decomposition properties of refuse plastic fuel (RPF), which is to be used as a cofiring fuel with a sub-bituminous coal at commercial circulating fluidized bed (CFB) boiler in Korea. In isothermal pyrolysis results, no change in the reaction model was observed in the temperature range of $375{\sim}450^{\circ}C$ and it was revealed that the first order chemical reaction (F1) is the most suitable among 12 reaction models. The activation energy shows similar results irrespective of application of reaction model in that the activation energy was 39.44 kcal/mol and 36.96 kcal/mol when using Arrhenius equation and iso-conversional method ($0.5{\leq}X{\leq}0.9$) respectively. Mean-while, the devolatilization time ($t_{dev}$) according to particle size (d) of RPF could be expressed as $t_{dev}=10.38d^{2.88}$ at $850^{\circ}C$, operation temperature of CFB and for even distribution and oxidation of RPF in CFB boiler, we found that the relationship of average dispersion distance (x) and particle size was $x{\leq}1.58d^{1.44}$.

• Polymer(Korea)
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• v.36 no.2
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• pp.245-250
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• 2012

Branched polypropylenes (PP) with long chain branch were prepared by solid state reaction with three different branching agent of 0.3 wt% content. The chemical structures, non-isothermal crystallization behavior and complex viscosity of the branched PP were investigated by FTIR, DSC, optical microscope, and dynamic rheological measurement. The chemical structure of the branched PP was confirmed by the existence of =C-H stretching peak of the branching agent at 3100 $cm^{-1}$. There was no distinct change in melting temperature in case of PP-D-0-3 and PP-F-0-3, but PP-H-0-3 indicated a decrease in melting temperature. The decrease in melting temperature was interpreted by the fact that the degradation reaction of PP was more dominant than branched reaction, and confirmed by a decrease in complex viscosity. The non-isothermal crystallization behavior of the branched PP was analyzed using by Avrami equation. The Avrami exponent of PP was 3, and the values of the branched PP with DVB and FS were below 3. The activation energy of PP calculated by Kissinger method was 25 kJ/mol, and there were no big difference in activation energies of the branched PPs compared to PP.