• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.477-484
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• 2019

As the residence time in the vehicle increases, the passenger desires a pleasant and stable riding environment in addition to the high driving performance of the vehicle. The windshield defrosting performance is one of the performance requirements that is essential for driver's safe driving. In order to improve the defrosting performance of the windshield of a vehicle, relevant elements such as the shape of the defrost nozzle should be appropriately designed. In this paper, CFD based numerical analysis is conducted to improve defrost performance of small electric vehicles. The defrost performance analysis was performed by changing the angle of the defrost nozzle and the guide vane that spray hot air to the windshield of the vehicle. Numerical simulation results show that the defrosting performance is best when the defrost nozzle angle is $70^{\circ}$ and the guide vane installation angle is $60^{\circ}$. Based on the analytical results, the defrosting experiment was performed by fabricating the defrost nozzle and the guide vane. As a result of the experiment, it is confirmed that the frost of windshield is removed by 80% within 20 minutes, and it is judged that the defrost performance satisfying the FVMSS 103 specification is secured.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.384-388
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• 2019

In winter season, the snow and ice accretion on the bottom of the high speed railway rolling stock and boogie part has fallen at a high speed from the ballast section (gravel section for the transmission of the rolling stock load received by sleepers and fixing sleepers), causing the gravel to be scattered, thereby damaging the railway rolling stock structures and facilities. In order to solve these problems, the gravel scattering prevention net, manual de-icing, and movable hot air machine were used, but their efficiency was low. For the more efficient de-icing than ever before, an optimum material for de-icing fluid for high speed railway rolling stock was developed by evaluating the ice melting capacity, kinematic viscosity, evaporation of the material used as a chemical de-icing fluid. Four kinds of organic acid salts (sodium formate, sodium acetate, potassium formate and potassium acetate) and two different alcohols (propylene glycol, glycerol) were used as evaluation materials. Potassium formate, potassium acetate, and propylene glycol had similar ice melting capacities in the indoor test, but the propylene glycol showed the best ice melting capacity in spraying the system simulation test. This is because the kinematic viscosity of propylene glycol was 2.989029 St, which is higher than those of other materials therefore, it could stay longer on the ice and de-icing. In addition, potassium formate and potassium acetate were difficult to be used since the crystals precipitated and adversely affected the appearance of the rolling stock. The propylene glycol is the most optimum as an de-icing fluid for the high speed railway rolling stock.

• Food Engineering Progress
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• v.21 no.4
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• pp.326-331
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• 2017

A cultivar (Malus domestica cv. Fuji) of apple was selected to make apple peel (AP) powder by three different powdering methods. Frozen AP was thawed and subsequently was dried or ground without drying. After AP was dried by hot-air drying at $60^{\circ}C$ or freeze-drying, the dried AP was ground using a conventional blender. Separately, the thawed AP was powered by using a cryogenic micro grinding technology (CMGT). The ground AP and three types of AP powder were extracted using deionized water, 20, 40, 60, 80, or 100% methanol, followed by vacuum evaporation. The total phenolics contents (TPC), total flavonoids contents (TFC), DPPH, and ABTS radical scavenging capacities of each extract were compared to determine an efficient powdering method. Lyophilized AP powder extract using 60% methanol showed the highest TPC and DPPH radical scavenging capacity. In contrast, 60% methanol extract of the powder by CMGT, resulting in the smallest particle, exhibited the highest TFC and ABTS radical scavenging capacity. This study suggests that the extraction yield of bioactive compounds from AP may be varied according to different powdering methods and that a new powdering process such as CMGT may be applicable to develop functional foods efficiently.

• Food Engineering Progress
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• v.22 no.4
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• pp.344-352
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• 2018

The effects of chemical compositions (protein, lipid, and dietary fiber) on the physical properties of dried biji powders were investigated. The raw biji was freeze-dried (control) and hot-air dried (untreated). The untreated biji was further defatted and deproteinated. The prepared biji powders were analyzed for the proximate composition, total dietary fiber (TDF), water absorption index (WAI), water solubility index (WSI), swelling power, solubility (including the quantification of soluble carbohydrate and protein fractions), and final viscosity (using a rapid visco analyzer). Control and untreated biji powders exhibited the similar chemical compositions. The defatted biji possessed higher TDF, although its protein content did not significantly differ for control and untreated ones. The deproteinated biji consisted mainly of TDF. WAI and swelling power increased in the order: deproteinated > defatted > control > untreated biji powders. WSI and solubility increased in the order: control > untreated > defatted > deproteinated biji powders. The similar patterns were observed for soluble carbohydrate and protein fractions. The deproteinated biji revealed the highest viscosity over applied temperatures, while the untreated one was lowest. Overall results suggested that the physical properties of the dried biji powder were reduced by protein and fat, but enhanced by dietary fiber.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.3
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• pp.89-95
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• 2022

In this study, glassy carbon coating was performed on the graphite using a phenolic resin and a curing agent was mixed with ethylene glycol as an additive to form the uniform surface. The phenolic resin was dried and cured under the environments of hot air, then converted into a glassy carbon layer by pyrolysis at 500~1,500℃. FTIR, XRD, SEM analysis, and density/porosity/contact angle measurement were performed for characterization of glassy carbon. The pyrolysis temperature for high-quality glassy carbon was optimized to be about 1,000℃. As the content of the additive increased, the effect of reducing surface defects on the coated surface, reduction of porosity, increase of contact angle, and increase of density were investigated in this study. The method of forming a glassy carbon coating layer through an additive is expected to be applicable to graphite coating and other fields.

• Journal of Bio-Environment Control
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• v.31 no.2
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• pp.125-132
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• 2022

This study aimed to examine cucumber (Cucumis sativus) varieties adaptive to the desert climate by comparing and analyzing the growth, yield, and water consumption. Two long-sized cucumber varieties, 'Gulfstream' and 'Imea' and two medium-sized cucumbers, 'Nagene' and 'Sausan' were cultivated in coir substrate hydroponics under hot and humid greenhouse conditions from March 2 to June 20, 2020. On the 113 DAT, 'Nagene' had the longest plant height and the highest internode number. The marketable fruit number per plant was higher in the medium-sized varieties, which had more internode number. The marketable fruit number was 31.3 for 'Gulfstream', 30.7 for 'Imea', 57.8 for 'Nagene', or 56.0 for 'Sausan' with no significant difference in total fruit weights per plant. The water consumption required to produce 200 g of fruit was lower in the 'Nagene' (2.39 L) with the highest water use efficiency (WUE). Therefore, 'Nagene' variety may have higher adaptability to desert high temperature compared to the long-sized varieties, and it is going to be necessary to verify more medium-sized cucumber varieties.

• The Korean Journal of Food And Nutrition
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• v.14 no.6
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• pp.573-578
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• 2001

Cholesterol oxidation products(COPs) such as 7-ketocholesterol, 7 ${\alpha}$, 7 ${\beta}$-hydroxycholesterol and 25-hydroxycholesterol were analyzed for ensuring the safety of squid during its drying and cooking. In addition. changes of malonaldehyde in squid during its drying and cooking were also investigated. Cholesterol was detected 636.4m9/1009 in fresh sample, which was decreased during its drying and cholesterol contents in dried sample were 468.9mg/100g, 486.8mg/100g, respectively, while COPs contents of sun and hot air dried samples increased about 6.2 times more than those contents of fresh sample. Regardless of cooking methods, the contents of COPs in dried products increased after cooking. Especially, those contents were determined 127.3 mg/g in sun dried samples were cooked by microwave oven. The malonaldehyde contents of dried products increased after cooking, its contents in cooked samples by an microwave oven after sun dried were about 4.3 times more than in control products. In general, a small quantity of COPs were formed in dried samples which were cooked by a steam.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.805-809
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• 1997

The influence of cool temperature occurred during the booting stage in 1993 on quality of rice grain was compared with that in favorable weather of 1994. The mean and minimum air temperatures during the reproductive growth stage at the paddy field of Jinbu Substation, National Crop Experiment Station were 2.2~7.4$^{\circ}C$ and 2.0~8.9$^{\circ}C$ lower respectively in 1993 compared to those of 1994. Grain fertility and brown rice yield were 11.8％ and 0.4t /ha, and 84.3％ and 5.5t /ha in 1993 and 1994, respectively. There was no difference in amylose content between two years. However, protein content of brown rice in 1994 were 1.6％ lower than that of 1993. There was no difference in alkali digestion value of milled rice between two years. Gel consistency of rice flour was 45mm in 1993 and 59mm in 1994. Amylogram characteristics of rice flour produced in 1993 showed lower peak hot, cool, and breakdown viscosities, and higher consistency and setback viscosities. The palatability of cooked rice by sensory panel test was considerably better in 1994 rice than in the rice of cool year.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.7
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• pp.485-496
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• 2018

In this paper, the smoke behavior in an underground station on operation of the fans in the ventiliation of the station was measured by the experimental method when the fire occurred in the underground station platform where the platfrom screen door was installed. The ventilation characteristics were compared when the ventilation system was operated and when the ventilation system was not operated when a fire occurred at the platform where the clean door was closed. To simulate the fire smoke, the smoke generated from the smoke generator was heated using a hot air fan. The transmittance was measured using a smoke density meter to quantitatively measure fire smoke. If the screen door is closed and the ventilation system of the underground station does not work, it is confirmed that if a fire occurs in the platform, smoke accumulates inside the platform, evacuating passengers is very difficult and can lead to a very dangerous situation. On the other hand, under the condition that the ventilation facility of the subway station is operated, the smoke evacuates to the outside through the ventilation facility of the underground station, and airflow is formed in the direction from the waiting room to the waiting area, so that the passenger located on the platform can safely evacuate toward the concourse. In the following paper, we will discuss the concurrent effect of tunnel ventilation through tunnel vent near the platform.

• Resources Recycling
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• v.32 no.6
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• pp.3-9
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• 2023

Separation of LED packages from PCBs and analysis of the adhesive components was conducted to enhance the recycling potential of LED modules. LED package was separated from PCBs using heat treatment under optimal conditions: temperature of above 250 ℃ and time of 20 minutes. The separation equipment can be established using a hot air injector with controlling the rotational speed of the internal screw. The separation efficiency of each type of substrate (aluminum and glass fiber) was investigated with the thickness range of the adhesive materials (0.25-0.30 and 0.30-0.35 mm). Under the optimal conditions, the efficiency can reach to 97.5% for both types of substrates with adhesive materials of thickness 0.25~0.30mm. Characterization of the residual adhesive substances from the separated LED package and PCB using microwave digestion and ICP analysis showed that the residue contained of 95% of Sn, less than 5% of Cu and Ag.