• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.1018-1024
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• 2008

The objective of this study is to compare the physicochemical properties and release characteristics of red ginseng (A) and tissue cultured mountain ginseng (B) extruded tissue cultured mountain ginsengs at barrel temperatures 110 (C) and $120^{\circ}C$ (D) to produce tissue cultured mountain ginseng-like comercial red ginseng by extrusion process. Extrusion process variables, water content and screw speed were fixed at 25% and 200 rpm, respectively. In the results, reducing and total sugar content were found to be relatively higher in A. The acidic polysaccharides content of B was the lowest among the ginseng samples. Acidic polysaccharide was increased 3 times by extrusion process. A and B were three times higher at maximum than C and D in polyphenolic compound. Polyphenolic compound content was relatively low by extrusion of ginsengs. Amino acid contents of B, C and D were $35{\sim}42\;{\mu}g/mL$; in contrast, A contained $25\;{\mu}g/mL$. The crude saponin content of C and D were higher than A and B.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.279-288
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• 2014

Nuclear energy is expected to meet the growing energy demand while avoiding CO2 emission. However, the problem of accumulating spent fuel from current nuclear power plants which is mainly composed of uranium oxides should be addressed. One of the most practical solutions is to reduce the spent oxide fuel and recycle it. Next-generation fuel cycles demand innovative features such as a reduction of the environmental load, improved safety, efficient recycling of resources, and feasible economics. Pyroprocessing based on molten salt electrolysis is one of the key technologies for reducing the amount of spent nuclear fuel and destroying toxic waste products, such as the long-life fission products. The oxide reduction process based on the electrochemical reduction in a LiCl-$Li_2O$ electrolyte has been developed for the volume reduction of PWR (Pressurized Water Reactor) spent fuels and for providing metal feeds for the electrorefining process. To speed up the electrochemical reduction process, the influences of the feed form for the cathode and the type of anode shroud on the reduction rate were investigated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7C
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• pp.680-690
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• 2006

In this paper, we present a bit allocation scheme based on grouped sub-channels for MIMO-OFDM (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) systems using V-BLAST (Vertical-Bell laboratories LAyered Space-Time) detector. A fully adaptive modulation and coding scheme may provide optimal performance in the MIMO-OFDM systems, however it requires excessive feedback information. Instead, SBA (Simplified Bit Allocation) scheme for reduction of feedback overhead, which applies the same modulation and coding to all the good sub-channels, may be considered. The proposed scheme in this paper named SBA-GS (Simplified Bit Allocation based on Grouped Sub-channels) groups sub-channels and assigns the same modulation and coding to the set of selected sub-channel groups. Simulation results show that the proposed scheme achieves comparable bit error rate performance of the conventional SBA scheme, while significantly reducing the feedback overhead in multipath channels with small delay spreads.

• Journal of Environmental Policy
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• v.6 no.1
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• pp.61-81
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• 2007

Types of agricultural policy can be catagorized into two general cases: price and income supports. Income supports are any government program designed to provide farmers with higher incomes than they would receive otherwise. These direct cash payments to farmers are known as "deficiency payment" or "direct payment" because they compensate the farmer for the failure of the market to provide farmers with adequate prices. The direct payment to environment-friendly agriculture is a form of income supports for the agriculture production using less pesticides and chemical fertilizers. Because no significant regulation exists on the use of fertilizers substituting chemical fertilizers for crop, the role of the payment on reducing environmental impacts of agriculture is not entirely clear. This uncertainty is likely to be particularly severe in the case that farmers with low-quality land showing greater demand for fertiliser have an incentive to transition to environment-friendly agriculture. The paper shows the case of the current payment system in Korea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1773-1778
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• 2009

Guava (Psidium guajava L.) contains high amount of vitamins and minerals, and its leaves have been reported to be very effective on reducing blood pressure. In this study, antimicrobial characteristics of extracts from four different parts of guava (fruit, branch, leaf, and seed) with four different solvents (methanol, ethanol, acetone, and water) were evaluated. Four targeted food-borne microorganisms were selected; two Gram negatives (Escherichia coli O157:H7 and Salmonella Typhimurium) and two Gram positives (Staphylococcus aureus and Listeria monocytogenes). By the paper disc method, guava extracts showed stronger clear hollow zone against Gram positive bacteria than Gram negatives in nutrient broth agar plate. Especially, extracts of branches and leaves showed significant antibacterial activity. Guava extracts also showed significant inhibition activity on the growth of Gram positive food-borne bacteria in nutrient broth. For example, S. aureus did not grow at all at 200 ppm of acetone extracts of guava branch and leaf. In the case of L. monocytogenes, the same concentration of acetone extracts of guava branch and leaf inhibited the growth 33.5% and 55.4%, respectively, at 32 hrs of incubation time. The results indicated that extracts of guava branch and leaf showed significant antibacterial activities against food-borne Gram positive microorganisms, and that guava branches, the byproducts of guava, might be a valuable resource for antibacterial materials.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2B
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• pp.187-192
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• 2011

Nitrate nitrogen is common contaminant in groundwater aquifers, its concentration is regulated many countries below 10 mg/L as N (As per WHO standards) in drinking water. An attempt was made to get optimal results for the treatment of nitrate nitrogen in groundwater by conducting various experiments by changing the experimental conditions for ZVI bipolar packed bed electrolytic cell. From the experimental results it is evident that the nitrate nitrogen removal is more effective when the reactor conditions are maintained in acidic range but when the acidic environment changes to alkaline due to the hydroxide formed during the process of ammonia nitrogen there by increasing the pH reducing the hydrogen ions required for reduction which leads to low effectiveness of the system. In the ZVI bipolar packed bed electrolytic cell, the packing ratio of 0.5~1:1 was found to be most effective for the treatment of nitrate nitrogen because ZVI particles are isolated and individual particle act like small electrode with low packing ratio. It is seen that formation of precipitate and acceleration of clogging incrementally for packing ratio more than 2:1, decreasing the nitrate nitrogen removal rate. When the voltage is increased it is seen that kinetics and current also increases but at the same time more electric power is consumed. In this experiment, the optimum voltage was determined to be 50V. At that time, nitrate nitrogen was removed by 94.9%.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.62-66
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• 2007

This study was carried out to develop the stable plug seedling production for hydroponics of spinaches by various nursery media, plug tray size and seed number per plug tray cell. When plant grown in various nursery media, the seeding stand rate was shown in order of granular rockwool with good water retention, granular rockwool>granular rockwool mixed with pearlite>cocopeat>pearlite>poly urethane foame. Thus, poly urethane foame indicated the lower seedling stand rate. There was no difference in growth of the seedlings md the seeding stand rate by the plug tray size, and no significant difference in the plant height and the number of leaves among the seed number per plug tray cell. But, leaf area of plant in 2 grains seeding per cell was $113.0cm^2$, was wider in compared with 5 grains seeding of which leaf area was $88.0cm^2$. Accordingly, the leaf area per plant decreased as more and more the number of seeds per plug tray cell increased. The fresh weight of a plant per plug tray cell was the heaviest with 12.5g in the 2 grains, and the total fresh weight of plants per cell was 33.9g in 4 grains seeding, thus it tended to was bigger compared with other treatments. Consequently, given that the number of seeds per cell was decreased, the fresh weight of a plant increased. On the other hand, the total fresh weight per cell showed a tendency to be reducing as more and more the number of seeds per plug tray cell decreased. The yield in the 4 grains seeding was increased by 46% as $14,910kg{\cdot}ha^{-1}$ in compared with the yield in 2 grains seeding as $10,200kg{\cdot}ha^{-1}$.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.273-279
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• 2009

This study was conducted to identify optimal concentrations of N (nitrogen) and K (Potassium) fertilizers on growth, yield and quality of melon (Cucumis melo. L) when they were grown with a fertigation culture in a greenhouse. Three strength (S) levels of fertilizers, including 1 S, 1/2S, and 1/4S were supplied N and K nutrients as using a trickle irrigation system. When the strength level of fertilizers was increased from 1/4S to 1 S, the level of EC (electronic conductivity) in soil was increased. Soil-water tension was ranged between -15 and -20kPa until fruit setting stage, whereas it was ranged between -45 and -50kPa in the later growth stages. In results, N fertilizer had effects on fruit yield and quality. A higher fruit yield was observed when plants were supplied with 1 S and 1/2S level of N fertilizer. The highest yield of marketable fruit, about 5,086kg/10a, was also observed when plants were supplied with 1/2S N fertilizer. A higher net index and sugar content of fruit was observed in the treatments of 1/2S and 1/4S level of N fertilizer compared to 1 S level. In contrast, there was no statistic difference in the yield and quality with three levels of K fertilizer. Results indicate that the 1/2S level for N and 1/4S level for K fertilizer are effective and optimal for the melon plants grown under the fertigation culture in terms of increasing fruit yield and quality and reducing the cost of fertilizers.

• Investigative Magnetic Resonance Imaging
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• v.20 no.1
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• pp.44-52
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• 2016

Purpose: To quantitatively and qualitatively compare fat-suppressed MRI quality using iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) with that using frequency selective fat-suppression (FSFS) T2- and postcontrast T1-weighted fast spin-echo images of the head and neck at 3T. Materials and Methods: The study was approved by our Institutional Review Board. Prospective MR image analysis was performed in 36 individuals at a single-center. Axial fat suppressed T2- and postcontrast T1-weighted images with IDEAL and FSFS were compared. Visual assessment was performed by two independent readers with respect to; 1) metallic artifacts around oral cavity, 2) susceptibility artifacts around upper airway, paranasal sinus, and head-neck junction, 3) homogeneity of fat suppression, 4) image sharpness, 5) tissue contrast of pathologies and lymph nodes. The signal-to-noise ratios (SNR) for each image sequence were assessed. Results: Both IDEAL fat suppressed T2- and T1-weighted images significantly reduced artifacts around airway, paranasal sinus, and head-neck junction, and significantly improved homogeneous fat suppression in compared to those using FSFS (P < 0.05 for all). IDEAL significantly decreased artifacts around oral cavity on T2-weighted images (P < 0.05, respectively) and improved sharpness, lesion-to-tissue, and lymph node-to-tissue contrast on T1-weighted images (P < 0.05 for all). The mean SNRs were significantly improved on both T1- and T2-weighted IDEAL images (P < 0.05 for all). Conclusion: IDEAL technique improves image quality in the head and neck by reducing artifacts with homogeneous fat suppression, while maintaining a high SNR.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.604-612
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• 2018

Coptis chinensis Franch is a valuable traditional oriental medicinal plant used for the treatment of various diseases. The major factors affecting the content of bioactive compounds and the relationship between bioactive compounds and antioxidant capacities of Coptis chinensis Franch were poorly understood. Thus, effects of the solvent, temperature, and extraction time on the extraction yields of bioactive compounds and the antioxidant activity of C. chinensis Franch extracts were investigated in this work. Our cluster analysis indicated that the hydroalcoholic solvent (50% ethanol : 50% water) at $35^{\circ}C$ for 30 min (extract time) was the best extraction condition for a factory use because the highest level of bioactive compounds and antioxidant activities was achieved. Multiple linear regression analysis revealed that total phenolic content (TPC) contributed to the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity, while both total alkaloid content (TAC) and total flavonoid content (TFC) were responsible for ferric reducing antioxidant power (FRAP) activity. These results indicated that extraction conditions controlled the yield of bioactive compounds and the antioxidant activity of C. chinensis Franch, which can provide important information for the industrial extraction.