• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.193-198
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• 2012

The following results are from the test of semi-gel electrolyte to store energy efficiently and use advanced VRLA batteries by photovoltaic and wind power generation. Semi-Gel electrolyte with Silica 5% became Gel after 1 and half hour. It shows it is the most suitable time that the electrolyte can be absorbed into the separator and active material of plate to be gel. The test also says that semi-gel electrolyte shows the much better performance for low-rate discharge and the liquid electrolyte is good for high-rate discharge because the reaction rate of gel electrolyte is slower than liquid one for high-rate discharge performance. The test with DOD10% and DOD100% says that 5% silica electrolyte shows much better performance for life efficiency than liquid one. Because semi-gel electrolyte increase the efficiency of gas recombination at the chemical reaction of VRLA battery and it makes minimizing the reduction of electrolyte. Using the 5% silica electrolyte in order to improve the stroage efficiency and life performance for photovoltic and wind power generation, it causes improving by 4.8% for DOD100% and 20% for DOD10%.

• Journal of the Korea Concrete Institute
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• v.29 no.3
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• pp.237-248
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• 2017

Frequent terror or military attack by explosion, impact, fire accidents have occurred recently. These attacks and incidents raised public concerns and anxiety of potential terrorist attacks on important infrastructures. However, structural behavioral researches on prestressed concrete (PSC) infrastructures such as Prestressed Concrete Containment Vessel (PCCV) and Liquefied Natural Gas (LNG) storage tanks under extreme loading are significantly lacking at this time. Also, researches on possible secondary fire scenarios after terror and bomb explosion has not been performed yet. Therefore, a study on PSC structural behavior from an blast-induced fire scenario was undertaken. To evaluate the blast-fire combined resistance capacity and its protective performance of bi-directional unbonded PSC member, blast-fire tests were carried out on $1,400mm{\times}1,000mm{\times}300mm$ PSC specimens. Blast loading tests were performed by the detonation of 25 kg ANFO explosive charge at 1.0 m standoff distance. Also, fire and blast-fire combined loading were tested using RABT fire loading curve. The test results are discussed in detail in the paper. The results can be used as basic research references for related research areas, which include protective design simulation under blast-fire combined loading.

• Korean Journal of Food Science and Technology
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• v.49 no.3
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• pp.235-241
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• 2017

Generally, peanuts are classified as high-fat foods as they possess high proportions of fatty acids. This study compared lipid constituents and properties between normal and high-oleic peanuts. Gas Chromatography-Flame Ionization Detector (GC-FID) analyses revealed that the fatty acid levels were significantly different between the normal and higholeic peanuts (p<0.05). Eight fatty acids were identified in the samples, including palmitic (C16:0), stearic (C18:0), oleic (C18:1, n9), linoleic (C18:2, n6), arachidic (C20:0), gondoic (C20:1, n9), behenic (C22:0), and lignoceric (C24:0) acids. Four tocopherol homologs were detected, and ${\alpha}$- and ${\gamma}$-tocopherols were the predominant ones. Tocopherols were rapidly decomposed during 25 day storage at $80^{\circ}C$. The main identified phytosterols were beta-sitosterol, ${\Delta}^5$-avenasterol, campesterol, and stigmasterol. Acid and peroxide values indicated that high-oleic peanuts have better oxidative stability than normal peanuts. These results can serve as the basis for the use of peanuts in the food industry.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.6
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• pp.309-312
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• 2017

The ceria powder is excellent in oxygen storage capacity (OSC) through the oxidation and reduction reaction of Ce ions and is used as a typical material for a three-way catalyst of an automobile which purifies the exhaust gas. However, since ceria generally has poor thermal stability at high temperatures, it is doped with metal ions to improve thermal stability. Therefore, in this study, Zr ions were doped into ceria powder, and their characteristics were further improved due to the increase of specific surface area with decreasing particle size due to doping. In this study, the synthesis of zirconium doped ceria nanopowder was synthesized by hydrothermal process. In order to synthesis Zr ion doped ceria nanopowder, the precursor reaction at was $200^{\circ}C$ for 6 hours. The average particle size of synthesized Zr doped $CeO_2$ nanopowder was below 20 nm. The specific surface area of synthesized Zr ion doped ceria nanopowder increased from $52.03m^2/g$ to $132.27m^2/g$ with Zr increased 30 %.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.45-53
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• 1997

Salted mackerel(Scomber japonicus) is favorite diet in Korea from ancient times. The formation of N-nitrosamine and amines such as VBN, TMAO, TMA and DMA in salted mackerels were investigated when nitrite was added to salting water at the concentration of 0, 100, 500 and 1000mg/kg and influence of cooking method on the formation of N-nitrosamine was also analyzed. The content of VBN in mackerel during the salting increased contineously; after 50 days it was approximately more than 23.8 times as compared with that of raw sample. The TMAO nitrogen decreased while TMA increased in mackerel during the salting, the amounts of TMAO and TMA were 3.7~21.0mg/100g and 15.0~20.4mg/100g in salted mackerel, respectively. The content of DMA nitrogen increased remarkably in mackerel during the salting; DMA in sample salted for 50 days reached about 16.0 times more than that of raw sample. N-Nitrosodimethylamine (NDMA) content of control sample was detected less than 1.0$\mu\textrm{g}$/kg, but nitrite addition to salting water at 100, 500 and 1000ppm resulted in NDMA content of 8.1~14.6$\mu\textrm{g}$/kg, 24.5~45.5$\mu\textrm{g}$/kg and 53.8~77.2$\mu\textrm{g}$/kg, respectively. In contrast, cooked counterparts contained 3.3~12.6$\mu\textrm{g}$/kg of NDMA. In general, more NDMA were produced during cooking when samples cooked using direct heating methods such as a gas range and a briquet fire than when samples were cooked using indrect heating methods such as an electric range.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.390-397
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• 2010

Residual solvents in foods are defined as organic volatile chemicals used or produced in manufacturing of extracts or additives, or functional foods. The solvents are not completely eliminated by practical manufacturing techniques and they also may become contaminated by solvents from packing, transportation or storage in warehouses. Because residual solvents have no nutritional value but may be hazardous to human health, there is a need to remove them from the final products or reduce their amounts to below acceptable levels. The purpose of this study was to develop and evaluate an analytical method for the screening of residual solvents in health functional foods. Furthermore, the aim of this study was to constitute a reasonable management system based on the current state of the market and case studies of foreign countries. Eleven volatile solvents such as MeOH, EtOH, trichloroethylene and hexane were separated depending on their column properties, temp. and time using Gas Chromatography (GC). After determining the GC conditions, a sample preparation method using HSS (Head Space Sampling) was developed. From the results, a method for analyzing residual solvents in health functional foods was developed considering matrix effect and interference from the sample obtained from the solution of solvents-free health functional foods spiked with 11 standards solutions. Validation test using the developed GC/HSS/MS (Mass Spectrometry) method was followed by tests for precision, accuracy, recovery, linearity and adequate sensitivity. Finally, examination of 104 samples grouped in suits was performed by the developed HSS/GC/MS for screening the solvents. The 11 solvents were isolated from health functional foods based on vapor pressure difference, and followed by separation within 15 minutes in a single run. The limt of detection (LOD), limit of quantification (LOQ), recovery and coefficient of variation (C.V.) of these compounds determined by the HSS/GC/MS were found to be 0.1 pg/mL, 0.1-125 pg/g, 51.0-104.6%, and less than 15%, respectively. Using the developed HSS/GC/MS method, residual solvent from 16 out of 104 health functional products were detected as a EtOH. This method therefore seems t o be a valuable extension ofanalytical method for the identification of residual solvents in health functional food.

• Journal of Life Science
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• v.26 no.12
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• pp.1438-1445
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• 2016

Yeast can be post-contaminated by the equipment, producer, or air, and this can degrade yogurt quality. This study aimed to demonstrate the yeast inhibiting effect in fermented milk by adding Lactobacillus paracasei and Lactobacillus rhamnosus along with current fermenting lactic acid bacteria such as Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. A certain amount of yeast was added to fermented milk samples that were soon after stored at variable temperatures, and the number of yeast cells was counted periodically. The swelling phenomenon caused by the gas produced by the yeast in fermented products was also observed. In the two experiments, compared to the control, the L. paracasei- and L. rhamnosus-added-groups showed much slower rate of yeast appearance and lower frequency of swelling phenomena. This suggests that using a mixture of L. paracasei and L. rhamnosus in fermented milk inhibits the growth of yeast. Furthermore, if the products are stored at $10^{\circ}C$, post-acidification is rarely seen in the experimental group compared to the control group. This means that the organoleptic flavor can be kept consistent from the production day till the expiration day, resulting in improved organoleptic quality for customers. In other words, the use of L. paracasei and L. rhamnosus in fermented milk will result in the following positive effects: improvement in storage stability by delaying yeast appearance, increase in quality consistency by inhibiting post-acidification, and improved organoleptic quality by enhancing texture and flavor.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.4
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• pp.29-42
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• 2017

As the "Guidelines for GHG Environmental Assessment" was revised, it pointed out that the developers should evaluate GHG sequestration and storage of the developing site. However, the current guidelines only taking into account the quantitative reduction lost within the development site, and did not consider the qualitative decrease in the carbon sequestration capacity of forest edge produced by developments. In order to assess the quantitative and qualitative effects of vegetation carbon uptake, the CASA-NPP model and satellite image spatial-temporal fusion were used to estimate the annual net primary production in 2005 and 2015. The development projects between 2006 and 2014 were examined for evaluate quantitative changes in development site and qualitative changes in surroundings by development types. The RMSE value of the satellite image fusion results is less than 0.1 and approaches 0, and the correlation coefficient is more than 0.6, which shows relatively high prediction accuracy. The NPP estimation results range from 0 to $1335.53g\;C/m^2$ year before development and from 0 to $1333.77g\;C/m^2$ year after development. As a result of analyzing NPP reduction amount within the development area by type of forest development, the difference is not significant by type of development but it shows the lowest change in the sports facilities development. It was also found that the vegetation was most affected by the edge vegetation of industrial development. This suggests that the industrial development causes additional development in the surrounding area and indirectly influences the carbon sequestration function of edge vegetaion due to the increase of the edge and influx of disturbed species. The NPP calculation method and results presented in this study can be applied to quantitative and qualitative impact assessment of before and after development, and it can be applied to policies related to greenhouse gas in environmental impact assessment.

• Journal of Food Hygiene and Safety
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• v.22 no.2
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• pp.99-104
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• 2007

To defend putrifaction of the processed rice cake from gas-forming yeast during storage and distribution it needed to reduce and remove them. The sanitizers of ethanol and organic acids were applied on Pichia anomala, Candida tropicalis, and isolated yeasts from the putrified cut rice cake. Although growth inhibition effect by the sanitizer of 20% ethanol, 1% acetic acid, or 1% lactic acid respectively were very low, the combined sanitizer of 20% ethanol and 1% acetic acid, or 1% lactic acid showed very high sterilizing effect toward the yeasts. Six log cfu/ml of the yeast was reduced with this combined sanitizers for 30 minutes. In addition, the combined sanitizer heated from 20 to $50^{\circ}C$ had more the increased sterility. Therefore, the sanitizer of the combined ethanol with the acetic acid or the lactic acid for 30 minutes at $50^{\circ}C$ might reduce or sterilize the putrifying yeast at the processed rice cake. The result might be also applied to the effective pre-treatment of many agricultural food stuffs, against yeast, especially unsterilized stuffs, without any hazards from the special sanitizers and nutritional loss from harsh sterilization.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.6
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• pp.51-56
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• 2009

Safety and quality assessment systems are very important in manufacture, storage, transportation, and handling of hazardous materials(hazmat) to prevent hazmat disasters. At present, hazardous materials exist everywhere in our daily lives with various forms of plastics, household products of cleaning and washing detergents, fertilizers or petroleum-related products. However, hazardous materials are dangerous substances when they are released to human or environment. Hazardous materials become very widely used substances in the age of oil-based industrial economy. The Korean Ministry of Environment (KMOE) describes about one hundred thousand types of chemicals are produced and used worldwide. Over four hundred new chemicals are introduced in every year. A crucial question for the Korean hazardous material management may have been raised: Will you be safe from hazardous material incidents? The gas leak disaster at Union Carbide's Bhopal, India in 1984 that made over 6,400 people killed and 30,000 to 40,000 people seriously injured is the representative case for the safety of hazmat. Korea becomes vulnerable to hazmat disaster due to the development of high-tech industry. Thus, the risk assessment system is required to Korea for transferring abandoned hazmat management systems to self-correcting safety systems. This research analyzed characteristics of various hazmat incidents applying statistical analysis methods including frequency analysis or analysis of category data to hazmat incidents for ten years. All of three analyses of category data indicate the significance of causality between hazmat incident site groups and seasons, regional groups, and incident casualty groups.