• Journal of Science Education
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• v.40 no.2
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• pp.144-165
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• 2016

The purpose of this study was to develop 'Appropriate Technology' theme STEAM Program for the elementary students and investigate the effects of the program on creative thinking activity, scientific attitude and leadership. Participants were 3grade 85 elementary school students. Before and after the program, the participants were asked to take the tests about creative thinking activity, scientific attitude and leadership. The major results of this study were as follows. First, the total score of experimental group's creative thinking activity and all 4 sub-domains was significantly improved than those of comparative group(p<.05). Second, the total score of experimental groups' scientific attitude was significantly improved than that of comparative group(p<.05). Among 7 sub-domains, curiosity, voluntariness, perseverance were significantly developed. Third, total score of experimental groups' leadership was significantly increased than that of comparative group after the STEAM program (p<.05). In the first factor, the score of inner and inter personal characteristics were significantly developed.

• Polymer(Korea)
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• v.37 no.6
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• pp.702-710
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• 2013

Zaltoprofen loaded polyoxalate (POX) microspheres were prepared by an emulsion solvent-evaporation/extraction method like oil-in-water (O/W) for sustained release of zaltoprofen. The influence of several preparation parameters such as fabrication temperature, stirring speed, intensity of the sonication, initial drug ratio, molecular weight ($M_w$) of POX, concentration of POX and concentration of emulsifier has been investigated on the zaltoprofen release profiles. Physicochemical properties and morphology of zaltoprofen loaded POX microspheres were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC) and Fourier transform infrared (FTIR). Through the analyzed results, it was demonstrated that the characteristics of the microspheres greatly affected by the prepared condition. The releases behavior of zaltoprofen was investigated for 10 days in vitro. It was confirmed that the release behavior of zaltoprofen can be controlled by the manufacturing factor of solvent-evaporation/extraction method.

• Food Science and Preservation
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• v.17 no.5
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• pp.602-607
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• 2010

The quality characteristics and shelf life of wet noodles containing a freeze-dried powder of Heracleum moellendorffii(HM) were studied to investigate the use of HM as a food ingredient. The weight, volume, and water absorption of wet noodle sprepared with HM(HML) decreased as the concentration of HM increased. The turbidity of HML sauce and the loss in the solid content of noodles after cooking were lower than those of control noodles. Whiteness(L) and redness(a) values of wet noodles decreased but yellowness(b) increased after addition of HM. The sensory qualities of HML, including appearance, taste, color, flavor, texture, and overall acceptability, were better than those of control noodles. Addition of HM to 0.6%(w/w) afforded the best sensory qualities with respect to taste, texture, and overall acceptability. The total polyphenol content of HML increased as HM concentration increased. Noodle DPPH free-radical-scavenging activities were 22%(control), 28.41%(0.3%HM addition), 40.22%(0.6%HM addition) and 49.42%(0.9%HM addition). Viable bacterial cell counts did not differ significantly between control noodles and those prepared using 0.6%(w/w)HM during storage for 6day sat $10^{\circ}C$. However, viable cell numbers in noodles prepared using 0.9%(w/w) HM were significantly lower than those of control samples and of noodles prepared using either 0.3%(w/w) or 0.6%(w/w) HM, during storage for 12 days at $10^{\circ}C$. Changes in pH values showed trends similar to those of viable cell numbers during storage.

• Applied Chemistry for Engineering
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• v.30 no.4
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• pp.435-444
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• 2019

In this study, two types of nonionic saccharide biosurfactants, GP-6 and GP-7, were prepared from coconut oil and the structure of resulting products was investigated by FT-IR, $^1H-NMR$ and $^{13}C-NMR$ spectrophotometer. The interfacial properties of GP-6 and GP-7 were found to be excellent from interfacial property measurements such as critical micelle concentration, static and dynamic surface tensions, interfacial tension, emulsification power, wetting property and foam stability. Detergency test evaluated by using a Terg-o-tometer showed moderately good detergency compared to that of conventional surfactants used in detergent formulations. Biodegradability, acute oral toxicity, acute dermal irritation and acute eye irritation tests revealed that both surfactants possess excellent mildness and superior environmental compatibility indicating the potential applicability to detergent products formulations. In particular, GP-6 can be considered as a strong candidate in detergent formulations since it is more surface active, mild and readily biodegradable than GP-7.

• Korean Journal of Environment and Ecology
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• v.34 no.6
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• pp.543-550
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• 2020

This study aimed to identify the characteristics of fish inhabiting Hapcheon Dam and surrounding rivers and the Bluegill population, an invasive species, and provide basic data. The survey of fish living in Hapcheon Dam and surrounding tributaries in the Ulsan area from 2016 to 2017 identified a total of 1,785 individuals of 30 species of 10 families and identified 8 Korea's endemic species (21.8% indigenization rate), 3 exotic species, and 2 ecosystem disturbance species. The comparison of this study with the past survey showed that 36 species of 12 families were reported in the past survey, but 14 species of them were not found in this study. We believe that a more detailed survey of Lake Hapcheon should identify most of them. The analysis of the length-weight relationship for the Bluegill population, identified as the dominant species in the Hapcheon Lake, showed that a large number of populations was in the stage of rapid growth as a large number of populations aged 1 to 2 years was found. Since the obesity level and the length-weight relationship were confirmed to be in good condition, it was necessary to prepare a plan to control the Bluegill population. We expect that this study's results can be useful data for understanding the growth and trends of the Bluegill population inhabiting the Hapcheon Dam and surrounding rivers.

• Food Engineering Progress
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• v.23 no.4
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• pp.283-289
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• 2019

This study was performed to determine the effect of psyllium husk addition on the physical properties of rice extrudates. Rice-based formulations mixed with psyllium husk (0, 7, 14 and 21%) were extruded at a die temperature of 140℃, screw speed of 200 rpm, and moisture content of 20%. As the content of psyllium husk increased, expansion ratio decreased, while piece density and specific length increased. Apparent elastic modulus, breaking strength, adhesiveness, and hardness augmented with an elevation in psyllium husk content. Lightness declined as psyllium husk content furthered, while redness, yellowness, and color difference intensified. Water soluble index and water absorption index increased with an increased amount of psyllium husk. In conclusion, the addition of psyllium affected the expansion of extruded rice snack possessing hard texture, small cells, and sticky texture due to higher water absorption during hydration.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.1-11
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• 2021

The purpose of this study was to analyze the trends and characteristics of 'stress urinary incontinence' research through word frequency analysis, and their relationships were modeled using word embedding. Abstract data of 9,868 papers containing abstracts in PubMed's MEDLINE were extracted using a Python program. Then, through frequency analysis, 10 keywords were selected according to the high frequency. The similarity of words related to keywords was analyzed by Word2Vec machine learning algorithm. The locations and distances of words were visualized using the t-SNE technique, and the groups were classified and analyzed. The number of studies related to stress urinary incontinence has increased rapidly since the 1980s. The keywords used most frequently in the abstract of the paper were 'woman', 'urethra', and 'surgery'. Through Word2Vec modeling, words such as 'female', 'urge', and 'symptom' were among the words that showed the highest relevance to the keywords in the study on stress urinary incontinence. In addition, through the t-SNE technique, keywords and related words could be classified into three groups focusing on symptoms, anatomical characteristics, and surgical interventions of stress urinary incontinence. This study is the first to examine trends in stress urinary incontinence-related studies using the keyword frequency analysis and word embedding of the abstract. The results of this study can be used as a basis for future researchers to select the subject and direction of the research field related to stress urinary incontinence.

• ANNALS OF ANIMAL RESOURCE SCIENCES
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• v.30 no.2
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• pp.69-78
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• 2019

The objective of this study was to investigate the quality properties of sausages added with the atmospheric pressure plasma treated extract of Perilla frutescens Britton var. acuta Kudo (red perilla). The lyophilized powder of red perilla extract treated by atmospheric-pressure plasma contained 7.5 g kg^-1 nitrite. Sausage samples were manufactured with the addition of sodium nitrite (Control), celery powder (Celery), or plasma-treated extract of red perilla (PTP) to obtain nitrite concentration of 70 mg kg^-1. The residual nitrite content was the lowest in PTP during storage for 21 days at 4℃ (p<0.05). The total aerobic bacteria counts were higher in PTP than in Control and Celery during storage at 4℃ (p<0.05). Malondialdehyde content of sausages was significantly lower in PTP than in Control and Celery during storage (p<0.05). PTP showed the lowest L^* value and the highest b^* value among the tested sausage samples during storage (p<0.05). PTP received the low scores in all the sensory properties of sausages because of its inherent color and flavor. The results suggested that the plasma-treated extract of red perilla was an unsuitable natural nitrite source for cured meat products because of its adverse effect on sensory quality. However, natural nitrite source with increased nitrite content can be produced by the treatment of the natural plant extract with atmospheric-pressure plasma.

• Journal of Adhesion and Interface
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• v.24 no.4
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• pp.124-130
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• 2023

For automotive coating agents that require little change in characteristics due to changes in external temperature, changes in noise characteristics due to changes in the external environment are very important. Therefore, soft polyurethane with excellent cold resistance, weather resistance, and abrasion resistance, and polysiloxane whose -OH terminated and side chains are modified with amines, are widely used. In this study, coating agents was prepared by adding water-born polyurethane, polysiloxane, ultra high molecular weight polypropylene (UHMWPP) powder, carbon black, and a matting agent to determine the effect of each resin component on noise. To study the effect of each resin component on noise, a coating agent was prepared by adding water-born polyurethane, polysiloxane, UHMWPP powder, carbon black, and a matting agent. The hard/soft segment ratio of water-born polyurethane, the main component of the coating, was 27.1%/72.9%, and the ratio of amino siloxanes to hydroxy-terminated polysiloxane was 2:7, which produced the least noise. The difference in friction coefficient was large when the friction body moves at high speed. When UHMWPP powder replaced SiO₂, noise decreased and gloss also decreased.

• Food Science of Animal Resources
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• v.29 no.2
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• pp.220-228
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• 2009

This study was conducted to determine the preblending effect of curing agents on the characteristics of mechanically deboned chicken meat (MDCM), including the pH, water-holding capacity (WHC), and stability under refrigeration conditions. MDCM was preblended with different curing agents [NaCl, 0.75 or 1.5%; sodium tripolyphosphate (STPP), 0.25 or 0.5%; ascorbic acid, 250 or 500 ppm; sodium nitrite, 75 or 150 ppm] and were stored at $4^{\circ}C$ overnight. The preblending of NaCl was found to have improved the WHC and emulsion stability; STPP was found to have improved the pH, WHC, and emulsion stability; and ascorbic acid or sodium nitrite did not affect the pH, WHC, and emulsion stability. The addition of ascorbic acid or sodium nitrite, however, decreased the 2-thiobarbituric acid (TBA) and volatile basic nitrogen (VBN) values of the preblended MDCM through the antioxidizing properties. The mixing effects of different curing agents on MDCM were also evaluated with nine different conditions. Among the treatments, the mixture of NaCl and STPP improved the WHC and emulsion stability due to the increased solubility of salt-soluble protein in the preblended MDCM. The mixture of NaCl, STPP, and ascorbic acid increased the pH, WHC, and emulsion stability, but the mixture of NaCl, STPP, ascorbic acid, and sodium nitrite improved the WHC, emulsion stability, and redness of the surface color with improved storage stability due to the decreased VBN and TBA values. As a result, the mixture of 1.5% NaCl, 0.5% STPP, 500 ppm ascorbic acid, and 75 ppm sodium nitrite showed the best properties as curing agents for MDCM preblending.