• Environmental Engineering Research
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• v.14 no.4
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• pp.220-225
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• 2009

The water quality in eutrophic lakes is affected by serious problems, such as abnormal increasing of Cyanobacteria. The purpose of this study was to investigate the possibility of a modified flotation system using a hybrid technique formed by chemical compounds and an electrostatic bridge. Therefore, experiments using the hybrid technique were performed to measure the zeta potential value on the phytoplankton surface and the removal efficiencies of phytoplankton, ammonia nitrogen, nitrate nitrogen and phosphoric acid. The results were as follows: Firstly, the zeta potential of M.aeruginosa was observed to approach charge neutralization due to adhesion of magnesium hydroxide precipitate on the phytoplankton surface in the pH range 10.5 to 11. Secondly, the concentration of chlorophyll-a decreased from about 150 to 20${\mu}g$g/L, with a maximum removal efficiency of 84% due to coagulation with pH values higher than 10. Thirdly, the N$H_4$-N concentration was observed to decrease from 0.62 to 0.54mg-N/L (13%), and the P$O_4$-P concentration, which is a limiting factor to the formation of algae blooms, decreased from 0.27 to 0.02mg-P/L (92%). These findings suggest that the modified flotation system can be applied for the purification of the raw water of numerous lakes containing high phytoplankton populations and elevated pH.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.220-220
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• 2006

• Journal of Animal Science and Technology
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• v.46 no.3
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• pp.387-396
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• 2004

This experiment was carried out to investigate the effects of dietary vitamin C and E on carcass characteristics of Hanwoo steers. Thirty seven Hanwoo steers were randomly assigned to one of four treatments. The four treatments were control(vitamin E 20 IU/kg feed), vitamin C(vitamin C 0.1%/kg feed and vitamin E 20 IU/kg feed), vitamin E(vitamin E 220 IU/kg feed) and vitamin C plus E(vitamin C 0.1%/kg feed and vitamin E 220 IU/kg feed). Hanwoo steers were fed experimental diets for 3 months of the last finishing period. Animals fed the diet containing vitamin C plus E had higher(P<0.05) yield grade than those fed the other diets but quality grade was not different between animals fed the control diet and vitamin-supplemented diets. Proximate analysis in longissimus dorsi was not different between animals fed the control diet and vitamin-supplemented diets. Vitamin C concentration in longissimus dorsi was higher (P<0.05) in the animals fed the vitamin C diet and the vitamin C plus E diet than in those fed the control diet and the vitamin E diet. Vitamin E concentration in longissimus dorsi was higher(P<0.05) in the animals fed the diet supplemented with vitamin E and the diet supplemented with vitamin C plus E than in those fed the control diet and the vitamin C diet. Animals fed the diet supplemented with vitamin C was higher(P<0.05) in myristic acid, palmitic acid, palmitoleic acid and oleic acid in the longissimus dorsi than those fed the other diets, but linoleic acid in longissimus dorsi was higher(P<0.05) in the animals fed the vitamin E diet than those fed the other diets. However, saturated fatty acid and unsaturated fatty acid were not different between animals fed the control diet and vitamin-supplemented diets.

• Culinary science and hospitality research
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• v.16 no.1
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• pp.269-279
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• 2010

This study investigates 4P's of developing food service products(Focused on Gwangju, Jeonnam area) and intends to set the direction for the relations between product, price, promotion, place and customer satisfaction and customer occupation. Statistical techniques employed includes reliability analysis and regression analysis. The study is based on the 220-questionnaire-survey conducted from July 6 to July 20, 2009 to five foodservice companies in Gwangju. The data collected of this study were analyzed with the frequency analysis, reliability analysis, and regression analysis using the SPSS 12.0 package program. The findings of this study are as follows. Firstly, there are significant product, price, promotion and place factors that affect customer satisfaction. Secondly, there are significant product, price, promotion and place factors that affect customer occupation. Thus, food service management needs to apply product, price, promotion and place strategies aggressively.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.6 no.1
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• pp.7-17
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• 1999

This study investigated the degree of knowledge achievement and self-confidence in aseptic technique as a part of the fundamental nursing practice classes. The subjects were 220 nursing students in a junior college in Chonnam and an applied Quasi-experimental research methodology was used thirty of them comprised an experimental group to examine learning according to the teaching method. Wata were collected over 80 days, from April to June 1988, analyzed using descriptive statistics, percentages, means, t-test, one way ANOVA, Pearson's correlation coefficient and stepwise multiple regression with the SAS program. The conclusions are as follows. 1. The mean score of the degree of knowledge achievement of aseptic technique of the 220 students was 0.68(possible score 1.0) before the lecture but was 0.88 after lecture(p=.000). 2. The mean score for aseptic technique of the 220 students was 3.41(possible score 5.0) before practice but was 4.27 after practice(p=.000). 3. The correlation of self-confidence before and after practice was relatively low(r=.25, p=.000). 4. The mean score of the degree of knowledge achievement of aseptic technique in the experimental group(selected 30 students) was 0.72 before the lecture but was 0.90 after the lecture. 5. The mean score of self-confidence on aseptic technique in the experimental group(selected 30 students) was 3.18 before practice but was 4.32 after practice(p=.000). 6. The mean score of learning according to the type of teaching to aseptic technique for the experimental group(selected 30 students) was 23.2(possibel score 34) after lecture and presentation, was 27.3 after learning through video tape, was 31.7 after presentation through practice, was 33.7 after first practical training, and was 34 after secondary practical training. As a result of this study, learning methods in the education of fundamental nursing skill effective for knowledge achievement and competence in practicing skill.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.384-386
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• 2014

Pseudomonas aeruginosa is an opportunistic pathogen that inhabits various natural and artificial environments, such as pathogenesis, water, soil and air. They can cause serious problems, such as pathogenic infection. In this study, 220 colonies were isolated from water and soil environment that assumed to be P. aeruginosa using a membrane filter method based on International Organization for Standardization (ISO/NP 16266). Identification of the isolates was determined by physiobiochemical characteristics using newly modified ISO method which includes the resistance to 1,10 phenanthroline test. Only one of 220 presumed P. aeruginosa strains isolated from effluence water using a drain swab was determined as P. aeruginosa-positive by the ISO/NP 16266 method. Subsequently, the resistance to 1,10 phenanthroline test, which was newly proposed by ISO in 2014 and applied in this study, was considered as more precise and improvable method for identification of P. aeruginosa.

• Journal of the Korean Society of Food Culture
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• v.31 no.3
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• pp.220-225
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• 2016

This study investigated properties of bread utilizing extracts of ginseng powder. Ginseng powder bread was baked. Addition of 1~3% of ginseng powder extract to wheat flour was carried out. Rheological properties, dough pH, dough volume, bread volume, water absorption capacity, baking loss, bread color, bread texture, and sensory evaluation were tested to examine properties of bread baked with extracts of ginseng powder. The results are as follows. The dough pH decreased gradually with increasing ginseng powder extract concentration. The bread volume, baking loss, and bread weight increased with increasing use of ginseng powder extract, and springiness and cohesiveness increased as red ginseng powder additive concentration increased. Lightness of the L decreased while a and b increased. In the sensory evaluation, ginseng powder with 1% ginseng powder extract was evaluated as the best for taste, texture, flavor, and overall acceptability.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.319-322
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• 2005

This paper describes practical tuning methods and testing of a digital PSS, which uses both frequency and power, with the 220MVA Chungpyung P/P #1 in the KEPCO system to enhance the damping of local modes. In the first step, the objective phase of PSS is computed through a phase leading function to provide compensation between the exciter reference point and the generator air-gap torque before tuning the PSS's time constants. In addition, eigenvalue analysis was used to determine a range of PSS's gain, whichis the more useful for field testing rather than a single gain value. The Real-Time Digital Simulator was used to verify safe operations of the PSS in the presence of disturbances, such as AVR step and three phase fault.

• KSBB Journal
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• v.29 no.3
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• pp.220-224
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• 2014

Flocculation is known one of the effective methods for harvesting microalgae. This study was aimed to optimize the flocculation condition for decreasing the amounts of flocculant and obtaining the highest yield of algal biomass. To achieve this goal, it was optimized the flocculant concentration, reaction pH and the concentration of cell density for harvest using response surface methodology (RSM). The flocculation of microalgae, Spirogyra varians, was carried out using inorganic flocculant polyaluminium chloride. By the RSM result, the optimal flocculation condition was calculated 5 ppm of polyaluminum chloride, pH 7.5 and 0.33 of optical cell density at $OD_{640}$. The obtained recovery yield of S. varians was 97.6% at the optimal condition.

• Journal of KIEE
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• v.11 no.1
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• pp.51-54
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• 2001

In this paper, a MW-Mvar investment technique focused on minimizing the system loss is presented. An optimization technique, in which the system loss is defined as the objective function and the power flow equations as the constraints, is introduced to obtain the Lagrangian multipliers λP and λQ. The Lagrangian multipliers imply the variation of the system loss with respect to incremental bus power and are used as MW-Mvar investment indices for minimizing the system loss. ΔP MW and ΔQ Mvar are invested, step by step, by the priority of λP and λQ index given for each bus. Derivation of the index uses the information from normal power flow calculation.