• Journal of Food Hygiene and Safety
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• v.20 no.2
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• pp.114-117
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• 2005

Although the removal efficiency of residual pesticides using tap water were ranged from -1.25 to $13.27\%$, the removal efficiencies of residual pesticides using both powder CaO and liquid CaO were $5.16\~l7.61,\;8.7\~41.59\%$, respectively. And those results showed much higher residual effect of the CaO washing than tap water washing. Natural CaO made by burning of scallop-shell considered to be a good reducing agent for pesticides. Furthermore, liquid CaO showed much higher removal efficiency than powder CaO. However, powder CaO also can be used as a good natural eliminator of pesticides in Mini-Tomato.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.387-396
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• 2015

The existing shield tunnel has constructed in the concept of non-drainage uniformly, but the leak has become a problem in the construction and management. The Shield tunnel design allowed for the water and earth pressure bring about the increasing segment thickness and the construction costs. In order to improve these problems, the study of the partial drainage shield tunnel is in progress. In this study, th model experiment was performed to confirm the possibility of the partial drainage shield tunnel. And the water and earth pressure was measured in drainage and undrained condition. Based on the results of model experiments, the effect of water pressure reduction was confirmed by reviewed the structure stability of the real design case.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.1
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• pp.23-31
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• 2003

Since the mid of 1990, permanent shotcrete tunnel linings such as Single-shell and NMT have been constructed in many countries for reducing the construction time and lowing construction costs instead of conventional in-situ concrete linings. Among essential technologies for successful application of permanent shotcrete linings, high performance shotcrete having high strength, high durability and better pumpability has to be developed in advance as an integral component. This paper presents the idea and first experimental attempts to increase early strength and bond strength of wet-mixed Steel Fiber Reinforced Shotcrete (SFRS) in spring water condition. In order to increase early behavior of SFRS, a new approach using high-early strength cement with alkali-free liquid accelerator has been investigated. From the test results, wet-mix SFRS with high-early strength cement and alkali-free accelerator exhibited excellent early compressive strength improvement compared to the ordinary portland cement and good bond strength even under spring water condition.

• The Journal of the Acoustical Society of Korea
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• v.37 no.1
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• pp.21-30
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• 2018

A passive time-reversal technique can improve error performance of the underwater communication system by reducing influence of inter-symbol interferences, which is caused by a multipath channel response. The passive time-reversal communication system equipped with numerous receivers generally can obtain superior error performance since larger diversity gain can be obtained as the number of available received signal increased. In this paper, we analyze the optimal number and combination of receivers that can approximately achieve the best error performance when using the limited number of receivers. For this analysis, we use communication data collected during SAVEX15 (Shallow-water Acoustic Variability Experiment 2015) carried out in the south-western part of Jeju Island from May 14 to May 28, 2015. Analysis results show that there are depths of energy concentration due to the channel characteristics in which the underwater sound channel are present, and the passive time-reversal technique using the limited number of the receivers can derive near-optimal communication performance if the receivers for time-reversal processing are located at the depths where energy is concentrated.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.654-658
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• 2010

The purpose of this study is to establish methods for enhancing the survival and growth of cold-water fish and crustacean larvae based on the nutritional components of zoo and phyto live foods. Rotifers, Brachionus rotundiformis, were cultured with a supplement of freshwater condensed Chlorella vulgaris at $28^{\circ}C$ and enriched with Algamac $2000^{(R)}$ at 16, 20 and $26^{\circ}C$, respectively. Isochrysis galbana, Chaetoceros calcitrans and Chlorella ellipsoidea were centrifuged for component analysis after being cultured for approximately one week with conway medium at $20^{\circ}C$. The crude protein and lipid contents of the rotifers were 58.4% and 10.9%, respectively, before enrichment. After enrichment at each temperature, total protein and essential amino acid contents were increased by reducing the enrichment temperature. However, unsaturated fatty acids and multiple fatty acid index (UI) showed their highest values at $20^{\circ}C$. Mono-unsaturated fatty acid content was highest (72.6%) at $16^{\circ}C$. The total protein contents of C. calcitrans and C. ellipsoidea were higher, 33.0% and 35.2%, respectively, than that of I. galbana, 27.8%. Methionin, leusine and histidine, essential amino acids of C. ellipsoidea, had considerably higher values, 50.2, 287.2 and 68.1 mg/g dry matter, respectively, compared to other microalgae. Total lipids, UI, DHA and n-3 PUFA of I. galbana had higher values, 23.6, 272.0, 12.9% and 45.2%, respectively, than other microalgae. Therefore, for cold-water fish and crustacean larvae that require high n-3 PUFA and DHA contents, enrichment of rotifers is desirable at $20^{\circ}C$. Fish larvae would also need more I. galbana than other microalgae.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.2
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• pp.138-142
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• 2013

As an early warning system to reduce the damage of aquacultured mollusks due to low salinity water, we investigated the possibility of a biomonitoring system measuring the shell valve movement (SVM) of Pacific oyster (Crassostrea gigas) by using the Hall element sensor. In high salinity water of 27 psu, SVMs of Pacific oyster showed spikes which mean a relatively fast closing condition after opened condition of average 10-15 mm, and then the SVM showed back to opening condition slower than closing speed. In water salinity of 20-27 psu, the SVMs were similar to that of 27 psu. However, below 17 psu, it showed abnormal valve movements such as spending more time for shell closure. In 10 psu, we could not detected SVMs due to closed condition during experiment periods. Thus, if we quickly detect abnormal environmental variations like low salinity using bio-monitoring of SVM, it may be contribute to increased productivity by dramatically reducing damages in aquaculture.

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.1-12
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• 2010

The objective of this study was to examine the hydrogeochemical and microbiological characteristics for stable maintenance of coastal LPG storage cavern. Cavern seepage water and groundwater in the vicinity of the LPG storage cavern were sampled and analyzed (February, May, August and October 2007). Groundwater samples of propane cavern showed high pHs of 8.1~12.4 due to dissolution of cement grouting materials that had been applied during the well and cavern construction. The EC values showed distinctive seasonal variation. The negative ORP indicated reduced condition. The seepage and surrounding groundwater are classified as Na-Cl type, which represents seawater effects. All of aerobic bacteria, anaerobic bacteria, slime forming bacteria and sulfate reducing bacteria were less than 500 CFU/mL, which indicated that there was no abrupt increase of bacteria in the cavern. Therefore there exist no hydrochemical symptoms to indicate unstable conditions of the cavern operation. However, regular and continuous monitoring is essentially required.

• Food Science of Animal Resources
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• v.38 no.3
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• pp.636-652
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• 2018

The study aims to determine the optimum sterilization rate and water activity of Chinese traditional smoke-cured bacon product (Larou) in the preservation with natural coating solution. With the response surface methodology (RSM), we analyzed 3 factors of processing conditions (the concentration of lysozyme, concentration of sodium alginate, and concentration of chitosan) and 2 response factors (sterilization rate and water activity). Sterilization rate and water activity of Larou were largely affected by the concentration of lysozyme, concentration of sodium alginate, and concentration of chitosan. The final optimum concentrations of lysozyme, sodium alginate, and chitosan were 0.09, 1.40, and 1.60% and realized the high sterilization rate. Water activity of sliced Larou was significantly correlated with the sterilization rate. Low-field nuclear magnetic resonance analysis verified the optimum processing conditions. The coating resulted in 99.69% rate of reducing bacteria after 30-day storage. The data of the total number of colony, peroxidation value, moisture content, pH, and sensory evaluation provided the theoretical basis for extending the shelf life of Chinese traditional smoke-cured bacon product (Larou) with natural coating solution.

• Preventive Nutrition and Food Science
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• v.21 no.3
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• pp.236-244
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• 2016

In this study, we compared the anti-inflammatory activity of Pinus koraiensis cone bark extracts prepared by conventional extraction and microwave-assisted extraction (MAE). Water extracts and 50% ethanol extracts prepared using MAE were applied to RAW 264.7 cell at 5, 10, 25, and $50{\mu}g/mL$ of concentrations, and tested for cytoxicity. The group treated with $50{\mu}g/mL$ of 50% ethanol extracts showed toxicity. In order to investigate the inhibition of nitric oxide (NO) production in RAW 264.7 cells, extracts of water and ethanol were treated with 5, 10, and $25{\mu}g/mL$ concentrations. The inhibitory activity of water and 50% ethanol extracts groups were determined as 40% and 60% at $25{\mu}g/mL$ concentration, respectively. We found concentration dependent decreases on inducible NO synthase. The inhibitory effect against forming inflammatory cytokines, prostaglandin $E_2$, tumor necrosis factor-${\alpha}$, interleukin (IL)-6, and IL-$1{\beta}$, was also superior in the $25{\mu}g/mL$ treated group than the control group. According to these results, the water extracts and 50% ethanol extracts both inhibited inflammatory mediators by reducing the inflammatory response. Therefore, The MAE extracts of P. koraiensis cone bark can be developed as a functional ingredient with anti-inflammatory activity.

• Korean Journal of Food Science and Technology
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• v.26 no.4
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• pp.403-410
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• 1994

Changes in physical and chemical characteristics of industry-type kochujang were investigated during 105 days of storage at $37^{\circ}C$. Reducing sugar content of kochujang decreased rapidly up to the 15th day of storage and then decreased slowly thereafter. Total free amino acid contents decreased by 22.3% after 60 days and by 35% after 90 days of storage. The activities of amylase and protease did not show any significant changes, however, the activity of neutral protease increased slightly. The moisture content and water activity of the kochujang decreased linealy during storage and the correlation coefficient between the moisture content and water activity showed 0.964. Apparent viscosity of kochujang increased with an increase in storage time. It was found that water activity was more responsible for the increase of apparent viscosity than water content.