• Food Science and Biotechnology
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• v.18 no.3
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• pp.661-666
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• 2009

The heat tolerance and the inactivation kinetics of peroxidase (POD) and polyphenol oxidase (PPO) in pineapples (Ananas comosus) were studied in the temperature range $45-95^{\circ}C$. The kinetic parameters, such as deactivation rate constant (k), activation energy ($E_a$), and decimal reduction rate (D) of the thermal inactivation process, were determined. POD in pineapples showed biphasic inactivation behavior at temperatures range $45-75^{\circ}C$ but was monophasic at $85-95^{\circ}C$. This indicate that POD has 2 isozymes, namely heat labile and heat resistant, with $E_a$ of 68.79 and 93.23 kJ/mol, respectively. On the other hand, the heat denaturation of pineapple PPO could be described as simple monophasic first-order behavior with $E_a$ of 80.15 kJ/mol. Thus, the results of this study is useful in blanching technology where it shows a shortened time with higher temperature can be applied. The determination of the heat tolerance and inactivation POD and PPO, at different temperature range as done in the present work, was very important to improve the blanching process. This also will help to optimize the pineapple canning process which is one of the most important food industries in many tropical regions.

• Journal of Life Science
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• v.21 no.1
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• pp.9-14
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• 2011

Perceived exertion involves detection and interpretation of sensations arising from the body during physical exercise. Physiological variables such as heart rate and oxygen consumption positively correlate with ratings of perceived exertion (RPE). It is unknown whether the accuracy of predicting exercise intensity from RPE differs between men and women. Therefore, it was examined whether men or women could predict relative exercise intensity, determined by oxygen consumption, more accurately from RPE. Ten male and ten female young adult subjects aged 25.1${\pm}$3.52 yr volunteered to participate. RPE were determined by the Borg 15-category scale, and a standard Bruce treadmill protocol was used to perform graded exercise testing. There was no significant difference in slope means between males and females (p=0.501). No significant difference was observed when plotting rates of perceived exertion (RPE) vs. percentage of $VO_2$ max. The relative maximal oxygen consumptions ($VO_{2max,\;}_{rel}$) were 52.36${\pm}$7.35 ml/kg/min for males and 41.44${\pm}$6.71 ml/kg/min for females, respectively and there was a significantly high difference between the two groups in the relative $VO_{2max}$, as well as figures of 4.05${\pm}$0.36 l/min for males and 2.53${\pm}$0.39 l/min for females in the absolute $VO_{2max}$ in this study. There were no significant differences in slope, y-intercept, and standard error of estimate (SEE) between males and females. No significant difference with RPE according to exercise intensity was found between males and females. However, RPE was a useful predictor of exercise intensity in independent genders.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.499-504
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• 2005

Polymer concrete shows excellent mechanical properties and chemical resistance compared with conventional normal cement concrete. The polymer concrete Is drawing a strong interest as high-performance materials in the construction industry Resins using recycled PET offer the possibility of a lower source cost of materials for making useful polymer concrete products. Also the recycling of PET in polymer concrete would help solve some of the solid waste problems Posed by plastics and save energy. An objective of this paper is to estimate the damage of sulfuric acid, through investigating recycled PET polymer concrete, immersed at sulfuric acid solution for 84 days. As a result of testing, recycled PET PC, used $CaCO_3$ as filler, makes a problem of appearance and strength if they are exposed for long term at corrosion environment. On the other hand, recycled PET PC, used fly-ash as filler, had less effect on decrease in weight and strength. Recycled PET PC is excellent chemical resistance, resulting in the role of unsaturated polyester resin which consists of polymer chain structure accomplishes bond of aggregates and filler strongly. Also, recycled PET PC, used fly-ash as filler, is stronger resistance of sulfuric acid corrosion than $CaCO_3$, because it is composed of $SiO_2$ and very strong glassy crystal structure. Therefore, recycled PET PC, used fly-ash as filler, is available under corrosion circumstances like sewer pipe or waste disposal plant.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.248-254
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• 2016

Efficacious wastewater treatment is essential for increasing sewage sludge volume and implementing strict environmental regulations. The operation cost of sludge treatment amounts up to 50% of the total costs for wastewater treatment plants, therefore, an economical sludge destruction method is crucially needed. Amid several destruction methods, wet air oxidation (WAO) can efficiently treat wastewater containing organic pollutants. It can be used not only for sludge destruction but also for useful by-product production. Volatile fatty acids (VFAs), one of many byproducts, is considered to be an important precursor of biofuel and chemical materials. Its high reaction condition has instituted the study of gravity pressure reactor (GPR) for an economical process of WAO to reduce operation cost. Simulation of subcritical condition was conducted using Aspen Plus with predictive Soave-Redlich-Kwong (PSRK) equation of state. Conjointly, simulation analysis for GPR depth, oxidizer type, sludge flow rate and oxidizer injection position was carried out. At GPR depth of 1000m and flow rate of 2 ton/h, the conversion and yield of VFAs were 92.02% and 0.17g/g, respectively.

• Journal of the Korean GEO-environmental Society
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• v.17 no.1
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• pp.5-12
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• 2016

Investigation of in-situ ground in cold region is difficult due to low accessibility and environmental factors. In this study, correlation between dynamic cone resistance and shear strength is suggested to estimate the strength of frozen soils by using instrumented dynamic cone penetrometer. Tests were conducted in freezing chamber after preparing sand-silt mixture with 2.3% water content. Vertical stresses of 5 kPa and 10 kPa were applied during freezing, shearing, and penetration phase to compare the dynamic cone resistance and shear strength. The dynamic cone resistance, additionally, is calculated to minimize the effect of energy loss during hammer impact. Experimental results show that as the shear strength increases, the dynamic cone penetration index (DCPI) decreases nonlinearly, while the dynamic cone resistance increases linearly. This study provides the useful correlation to evaluate strength properties of the frozen soils from the dynamic cone penetration and direct shear tests.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.291-299
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• 1997

As a microimaging device detecting gamma rays emitted from small lesions or tumors during operation, the intraoperative surgical probe has been proposed and is now under development. We have designed a multipurpose portable gamma prove system and evaluated the performance both for the absolute counting purpose of residual radioactivities and for the localizing capability of gamma events using the NaI(Tl) crystal and two types of photomultiplier tubes(PMTs). Counting efficiencies in the range of routine clinical use of radiation dose were measured using the assembly of single channel PMTs and 0.5 inch thick NaI(Tl) crystal of 1 inch diameter. The positioning of gamma events for imaging purpose requires the multiple channel PMTs with appropriate positioning electronics. We have designed a simple and reliable positioning circuit based on the concept of modified Anger. In preliminary experiments using the multiple channel PMT of 3 inch diameter and the dim lighth source, we were able to trace and localize the correct position with reduced positioning error by the use of two multiplier/divider chipset and simplified peripherals. The energy resolutions for the counting gamma probe measured as full width at half maximum(FWHM) for Cs-137, F-18, Tc-99m were 12%, 13%, and 36%, respectively. The spatial resolution for the imaging gamma probe measured as FWHM for green LED was 2.9 mm. The results indicate that the currently developing probe is very promising and could be very useful for many applications in nuclear medicine. Future studies will include developing collimators, improving interface hardwares, and evaluating the system with clinical data.

• Korean Journal of Community Nutrition
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• v.19 no.2
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• pp.142-162
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• 2014

Objectives: To evaluate the critical environmental factors on healthy-aging of Korean people, we investigated the significant factors influencing health status of septuagenarians living in rural area of Jeonla province, known to be one of the representative longevity regions in Korea. Methods: We divided subjects into healthy group (36M/25F) or poor-health group (26M/73F) based on self-reported health status, body mass index, a number of prescription, and blood test data. General characteristics, physical measurements, lifestyle, dietary behavior and nutrient intake, physical health and mental health data were statistically compared between the two groups. Results: Average age was not different between healthy group and poor-health group in men and women, respectively. In men, significantly favorable factors to health were observed to be higher education, regular exercise, higher grip strength and walking function, body mass index (${\geq}18.5kg/m^2$), moderate frequency of drinking and eating-out, non-smoking, normal red blood cell (RBC) count, higher serum dehydroepiandrosterone-sulfate (DHEAS) level, good digestive function and appetite, normal hearing function, regular meals, adequate vegetable and fruit intake, diverse food intake, adequate energy and nutrients (protein, vitamin $B_1$, $B_6$, C and E, folate, niacin, P, Zn and K) intake, higher mini-nutrient status assessment (MNA) score and low level of depression. On the other hand, in women, those were literacy, living arrangement, moderate frequency of drinking, healthy teeth, higher grip strength and walking function, bone mineral density, normal RBC and white blood cell (WBC) count, higher DHEAS concentration, higher MNA score, normal cognition and memory function, having snack and adequate fruit intake. Conclusions: These results could be useful to plan effective strategies to increase health-life expectancy of Korean old people living in rural areas.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2010.03a
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• pp.40-40
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• 2010

Studies on attractive color changing property of dye chromophore and fluorophore have been greatly enjoyed in the related industrial and research fields such as optoelectronics, chemosensor, biosensor and so on. The optical property based on D-$\Pi$-A intramolecular charge transfer (ICT) system of chromophore molecules can be utilized as suitable sensing probes for checking media polarity and determining colorimetric chemosensing effect, especially heavy metal detection. These finding are obtained by absorption and emission properties. In this work, donor-acceptor D-$\Pi$-A type fluorescent dyes were designed and synthesized with the corresponding donor and acceptor groups. The selected donor moieties might be provided prominent amorphous properties which are very useful in designing and synthesizing functional polymers and in fabricating devices. Another reasons to choose are commercial availabilities in high purity and low price. Donor-bridge-acceptor (D-A) type dyes can produce impressive optical-physical properties, yielding them potentially suitable for applications in the synthesis of small functional organic molecules. Small organic functional molecules have unique advantages, such as better solubility, amorphous character, and represent an area of research which needs to be explored and developed. Currently, their applications in metalorganic compounds is rapidly expanding and becoming widespread in self-assembly processes, photoluminescence applications, chiral organocatalysts, and ingrafts with nanomaterials. Colloidal nanoparticles have received great attentions in recent years. The photophysical properties of nanoparticles, particularly in terms of brightness, photostability, emission color purity and broad adsorption range, are very attractive functions in many applications. To our knowledge background, colloidal nanoparticles have been enjoyed their applications in bio-probe research fields. This research interest can be raised by the advantages of the materials such as high photoluminescence quantum yields, sharp emission band, long-term photostability and broad excitation spectra. In recent, the uses of nanoparticles being embedded in a polymer matrix and binded on polymer surface have been explored and their properties such as photo-activation and strong photoluminescence have been proposed. The prepared chromophores and nanoparticles were investigated with absorption and emission properties, solvatochromic behaviors, pH induced color switching effects, chemosensing effects and HOMO/LUMO energy potentials with computer simulation. In addition, synthesized fluorophore dyes and particles were applied onto PE/Aramid fiber fluorescing colorations. And the related details were then discussed.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.129-133
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• 2012

To exploit plant growth promoting bacteria in the roots of Miscanthus sacchariflorus, a biomass energy crop, total 64 bacteria were isolated. For the investigation of plant growth promoting effects from the isolated bacteria, production of indole acetic acid (IAA) and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activities were tested and other cultural conditions were examined. As results, 8 isolates showed plant growth promoting effects on the M. sacchariflorus and an isolate designated Agrobacterium sp. BE516 has the highest activity by enhancing the shoot elongation over 2-fold than the control. Agrobacterium sp. BE516 produced 64 ${\mu}g$ IAA per mL and showed ACC deaminase activity which is involved in the resistance to environmental stress such as high salt and drought. It could grow at low temperature in the range from 4 to $15^{\circ}C$, at pH 4.0 and at 4% NaCl. These results indicate that the Agrobacterium sp. BE516 can be useful as a bio-fertilizer for M. sacchariflorus under the stressed conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.723-730
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• 2016

Solar cells in a PV module are connected in series and parallel to produce a higher voltage and current. The PV module has performance characteristics depending on solar radiation and temperature. In addition, the PV system causes power loss by special situations, including the shadows of the surrounding environment, such as nearby buildings and trees. In other words, an increase in power loss and a decrease in life cycle can occur because of the partial shadow and hot-spot effect. Therefore, this paper proposes the optimal configuration algorithm of a bypass diode to improve the output of a PV module and one of a PV array to minimize the loss of the PV array. In addition, this paper presents a model of a PV module and PV array based on the PSIM S/W. The simulation results confirmed that the proposed optimal configuration algorithms are useful tools for improving the performance of PV system.