• KSBB Journal
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• v.17 no.2
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• pp.176-181
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• 2002

Astaxanthin (3,3＇-dihydroxy-${\beta}$, ${\beta}$-carotene-4-4＇-dione), a natural pigment of pink to red color, is widely distributed in nature particularly in the skin layer of salmonoids and the crust of shrimp, lobster, etc. Recently, it was produced from the yeast culture of Phaffia rhodozyma. Because of its high thermal stability and antioxidant functionality, its applications can be extended into food, cosmetics, and pharmaceutical ingredient beyond the traditional feed additive. Because of its very high lipophilicity, astaxanthin has been extracted traditionally by strong organic solvents such as chloroform, petroleum ether, acetone, etc. In this study, we developed a surfactant-based solubillization system for astaxanthin, and used it to extract astaxanthin from disrupted yeast cells. Among Tween 20, Triton X-100 and SDS, Tween 20 was identified as the most suitable surfactant in terms of extraction capacity and safety. The ethylene oxide group of Tween 20 was identified as the most significant factor to increase the HLB value that determined the extraction capacity. The effects of micelle formation condition, such as the molar ratio of astaxanthin and Tween 20, pH, and ionic strength were also investigated. pH and ionic strength showed no significant effects. The optimal molar ratio between astaxanthin and Tween 20 was 1 : 12. Antioxidant activity of astaxanthin was higher than ${\beta}$-carotene and ${\alpha}$-tocopherol. Astaxanthin in the crude extract from the yeast cell was more resistant to air and/or light degradation than pure astaxanthin, probably because of the presence of other carotenoids and lipids.

• Preventive Nutrition and Food Science
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• v.15 no.2
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• pp.143-146
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• 2010

Organic zinc was included in the diet of broiler chickens to examine its effect on the skin characteristics and the expression level of skin proteins. Broiler chicks (Ross$\times$Ross) were fed a corn-wheat-soybean meal basal diet, either as control or containing an additional 80 ppm of zinc proteinate for 4 weeks, and then five broilers from each treatment were selected randomly, slaughtered, and their skin characteristics were examined. There were significant increases (p<0.05) in thigh skin epidermis and dermis thickness in the chicks fed organic zinc. Collagen content in the skin of broilers was also increased by the addition of organic zinc to the diet. 2D-gel electrophoresis patterns indicated that expression levels of the three proteins, glyoxylase 1, hypothetical protein, and dispersin B were affected by zinc feeding. These results suggest that adding organic zinc to the chicken's feed may contribute to decreased skin tearing.

• Journal of Power Electronics
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• v.16 no.3
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• pp.1110-1121
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• 2016

The mathematical model of a three phase PWM converter under the stationary αβ reference frame is deduced and constructed based on a Proportional-Resonant (PR) regulator, which can replace trigonometric function calculation, Park transformation, real-time detection of a Phase Locked Loop and feed-forward decoupling with the proposed accurate calculation of the inductance voltage vector. To avoid the parallel resonance of the LCL topology, the active damping method of the proportional capacitor-current feedback is employed. As to current vector error elimination, an optimized PR controller of the inner current loop is proposed with the zero-pole matching (ZPM) and cancellation method to configure the regulator. The impacts on system's characteristics and stability margin caused by the PR controller and control parameter variations in the inner-current loop are analyzed, and the correlations among active damping feedback coefficient, sampling and transport delay, and system robustness have been established. An equivalent model of the inner current loop is studied via the pole-zero locus along with the pole placement method and frequency response characteristics. Then, the parameter values of the control system are chosen according to their decisive roles and performance indicators. Finally, simulation and experimental results obtained while adopting the proposed method illustrated its feasibility and effectiveness, and the inner current loop achieved zero static error tracking with a good dynamic response and steady-state performance.

• Korean Journal of Agricultural Science
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• v.48 no.1
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• pp.133-140
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• 2021

The aim of this study was to evaluate the growth performance between two different crossbred strains of Korean native chickens denoted as 1A and 2A compared to white semi broilers and Ross (RR) from hatching to 40 days. In total, 576 one-day-old chicks were allocated in a completely randomized design to give 18 replicate cages each (eight chicks per cage). The two-phase feeding program consisted of the starter (day 1 - 21: Crude protein [CP] 20% and metabolizable energy [ME], 3,050 kcal·kg^-1) and the grower (day 22 - 40: CP 18%, 3,100 kcal·kg^-1). The results revealed that 1A and 2A had a lower (p < 0.05) body weight (BW) from day 1 to day 40 compared with the other groups. A lower (p < 0.05) average daily gain (ADG) was observed in 1A and 2A during the entire period when compared with the other groups. The 1A and 2A groups had the minimum (p < 0.05) average daily feed intake (ADFI) compared with the other groups for the whole period. The RR had an improved (p < 0.05) FCR compared with the other groups during the whole period. The 1A and 2A groups were observed to have the lowest (p < 0.05) shank length compared with the other groups during the entire period.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.719-727
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• 2021

This study was conducted to evaluate the effects of mixed and separate gender feeding on the growth performance and carcass traits of Korean native chickens (KNC) compared to white semi-broilers (WSB) and a commercial broiler (CB) from hatching to 35 days. Here, 240 chicks were used with eight birds per cage in a randomized design with six replicates per breed. For the KNC lines, three groups of males (KNC-M), mixed-gender birds (KNC-FM) and females (KNC-F) were used. The two-phase feeding program used here consisted of a starter phase (days 1 - 21: crude protein [CP] 20% and metabolizable energy [ME], 3,050 kcal·kg^-1) and a grower phase (days 22 - 35: CP 18%, 3,100 kcal·kg^-1) for a commercial broiler. The WSB and CB were fed the only starter commercial diet. Fresh water and feed were provided ad-libitum. The results revealed that the KNC group had a lower (p < 0.05) body weight (BW) from day 7 and day 35 compared to that of the CB. Furthermore, the KNC group showed a lower (p > 0.05) average daily gain (ADG) relative to that of the CB during the entire experimental period. No difference (p > 0.05) was observed in the shank length among the treatments. There were also no significant differences in the growth performance or carcass traits between the KNC-M and WSB groups or in the genders of the KNC group.

• Korean Journal of Exercise Nutrition
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• v.16 no.2
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• pp.85-92
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• 2012

This study was conducted to examine the possibility of Salicornia herbacea L. powder as a functional food beneficially affecting carbohydrate metabolism and antioxidant capacity. Twenty-four, 6-week old, maleSprague-Dawleyrats were classified into three groups: normal diet control (CON), high-fat diet control (HFC) and high fat diet + Salicornia herbacea L. (SHF). Related feed was provided to each group for 4 weeks. Weight gain rate increased most in the HFC rats, and the concentration of glucose was significantly high in both the HFC and SHF groups, compared to the CON group. The SHF group showed a significantly high expression rate of Glut 4 (21.36%), compared to the CON and HFC groups. The glycogen content in muscle was significantly high in both the HFC and SHF groups, compared to the CON group. There were significant differences in the malondialdehydecontent in muscles between the groups, with the content in the CON and HFC groups being significantly higher than the SHF group. All the groups showed a similar tendency to each other in the liver tissue as well. Concerning the expression of Cu,Zn-super oxide dismutase andglutathione peroxidaseproteins, the SHF group was significantly higher than the CON and HFC groups. Overall, the experiment result above implies a possibility that an intake of Salicornia herbacea L. powder can regulate weight by decreasing the weight gain rate, further suggesting its effectiveness as a functional food before exercise by increasing the energy storage capacity and antioxidant capacity.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.209-216
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• 2024

Land shrimp farms can control the growth environment more stably than coastal ones, making them advantageous for high-quality, large-scale production. In order to maintain an optimal shrimp growth environment, various factors such as water circulation, maintaining appropriate water temperature, oxygen supply, and feed supply must be managed. In particular, failure to properly manage water quality can lead to the death of shrimp, making it difficult to have people stationed at the farm 24 hours a day to continuously manage them. In this paper, to solve this problem, we design an integrated monitoring system for land farms that can be operated with minimal manpower. The proposed design plan uses IoT technology to collect real-time images of land farms, pump status, water quality data, and energy usage and transmit them to the server. Through web interfaces and smartphone apps, administrators can check the status of the farm stored on the server anytime, anywhere in real time and take necessary measures. Therefore, it is possible to significantly reduce field work hours without the need for managers to reside in the farm.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.249-255
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• 2013

The objective of this study was to investigate the exposure assessment of Korean consumers to edifenphos and tricyclazole in cattle product fed the rice straw, using a probabilistic approach. We used tricyclazole and edifenphos residue data in rice straw reported by National Academy of Agricultural Science (NAAS) for the 1998, 1999, 2001 and 2010 monitoring study and National Agricultural Products Quality Management Service (NAQS) for 2009 monitoring study. The mean exposures of edifenphos and tricyclazole for all of Korean consumers were 0.027% and 0.0006% of ADI and $99%^{th}$ percentile exposures were 0.034% and 0.0007% of ADI respectively. The group of 1~6 years old consumers has the lowest exposure of edifenphos and tricyclazole. The group of 19~29 years old consumers has the highest exposure of edifenphos and tricyclazole.

• Applied Chemistry for Engineering
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• v.20 no.4
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• pp.391-395
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• 2009

For the conversion of domestic waste-wood into energy, a fixed bed gasifier ($0.9 m{\times}2.4 m$) having the capacity of 2 ton/day was designed and constructed. The dual knife valve was used to feed waste-wood of which size was 3~5 cm and a rotary stoker system was installed in the bottom of gasifier. The pilot gasification system consisted of feeding system, fixed bed gasifier, gravity fine particle collector, heat exchanger for syngas cooling, ID fan, and cooling tower. The operation temperatures of gasifier were $700{\sim}1000^{\circ}C$ and the concentrations of syngas were CO: 25~40 vol%, $H_2$: 7~12 vol%, $CH_4$: 2~4 vol%, $CO_2$: 12~24 vol%. The calorific value of syngas was $1100{\sim}1500kcal/Nm^3$ and was enough to be applied in the industrial combustor. Also the gas engine was operated by using syngas from biomass gasifier and produced 1~4 kW of power.

• Journal of Food Hygiene and Safety
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• v.31 no.6
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• pp.432-438
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• 2016

Ethoxyquin (EQ, 1,2-dihydro-6-ethoxy-2,2,4-trimethyl-quinoline) is quinoline-based antioxidant used in the animal feed and food industry to protect the raw materials and final products against oxidation. In recent years the use of synthetic antioxidants in fishmeal ingredients carry-over to farmed fish fillets has received increasing attention in food safety. This study was conducted to develop an analytical method to determine EQ in aquatic products. The analytes were confirmed and quantified via liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the positive ion mode using multiple reaction monitoring (MRM). The sample was extracted with 1 N HCl (in case of flatfish extracted with 1 N HCl containing 10% acetonitrile). Then, solid phase extraction (SPE) was used for the cleanup. Standard calibration curves presented linearity with the correlation coefficient ($r^2$) > 0.99, analyzed at 0.005-0.2 mg/kg concentration. The developed method was validated according to the Codex Alimentarius Commission (CAC) guideline. The limits of quantitation for EQ were 0.01 mg/kg. Average recoveries ranged from 81.3% to 107%. The repeatability of measurements, expressed as the coefficient of variation (CV, %), was below 10%. The analytical method was characterized with high accuracy and acceptable sensitivity to meet CODEX guideline requirements and would be applicable to analyze the EQ residue in aquatic products.