• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.286-294
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• 2003

This study was attempted to understand seasonal dynamics of phyto- and zooplankton communities in shallow, eutrophic Lake llgam and to compare them with the PEG (Plankton Ecology Group) model. Seasonal succession pattern of phytoplankton community was similar to PEG model as Chlorophyceae and Baciliphyceae increase during spring and autumn fellowed by increase of Cyanophyceae. However, based on the cell density and biomass, a dominant phytoplankton community differed with PEG model: Cyanophyceae had been a dominant community throughout a year, except for ice-cover period during which Chlorophyceae was a dominant group. In spring, when ice melted and dissolved nutrients in water column increased, the increase of Chlorophyceae occurred: when nutrients (DIN and DIP) rapidly decreased, Cyanophyceae increase occurred. Microcystis, Oscillatoria, Lyngbya, Merismopedia were maior dominant species of Cyanophyceae and their cell density and/or biomass was the highest in October 2000 (12.9${\pm}$5.8${\times}10^5$ cells/ml, 3.5${\pm}$0.9${\times}10^3{\mu}gC/l$). Cyanophyceae biomass showed positive relationship with chlorophyll a ($r^2$ = 0.71,P< 0.001) and TP concentration ($r^2$ = 0.62, P< 0.001). Small-sized rotifers such as Keratella cochlearis, increased between March and May when Chlorophyceae increased. Both high standing crop of copepods and cladocerans, such as Diaphanosoma brachyrum and Bosmina longirostris occurred between June and September accompanied with the increase of Dinophyceae and Bacillariophyceae. There was no evidence that clear-water phase was caused by zooplankton grazing. The diversity and evenness index of phyto- and/or zooplankton increased with chlorophyll a concentration. These results suggest zooplankton grazing and limiting nutrient deficiency could lead to change of phytoplankton biomass, but not the phytoplankton community in Lake llgam.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.12
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• pp.1098-1125
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• 2000

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 1998 and 1999 has been done. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environment. The conclusions are as follows. 1) A review of the recent studies on fluid flow, turbomachinery and pipe-network shows that many experimental investigations are conducted in applications of impingement jets. Researches on turbulent flows, pipe flows, pipe-networks are focused on analyses of practical systems and prediction of system performance. The results of noise reduction in the turbomachinery are also reported. 2) A review of the recent studies on heat transfer analysis and heat exchanger shows that there were many papers on the channel flow with the application to the design of heat exchanger in the heat transfer analysis. Various experimental and numerical papers on heat exchanger were also published, however, there were few papers available for the analysis of whole system including heat exchanger. 3) A review of the recent studies on heat pump system have focused on the multi-type system and the heat pump cycle to utilize treated sewage as the heat source. The defrosting and the frosting behaviors in the fin-tube heat exchanger is experimentally examined by several authors. Several papers on the ice storage cooling system are presented to show the dynamic simulation program and optimal operation conditions. The study on the micro heat pipes for the cooling of high power electronic components is carried out to examine the characteristics of heat and mass transfer processed. In addition to these, new type of separate thermosyphon is studied experimentally. 4) The recent studies on refrigeration/air conditioning system have focused on the system performance and efficiency for new alternative refrigerants. New systems operating with natural refrigerants are drawing lots of attention. In addition to these, evaporation and condensation heat transfer characteristics of traditional and new refrigerants are investigated for plain tubes and also for microfin tubes. Capillary tubes and orifice are main topics of research as expansion devices and studies on thermophysical properties of new refrigerants and refrigerant/oil mixtures are widely carried out. 5) A review of the recent studies on absorption cooling system shows that numerous experimental and analytical studies on the improvement of absorber performance have been presented. Dynamic analysis of compressor have been performed to understand its vibration characteristics. However research works on tow-phase flow and heat transfer, which could be encountered in the refrigeration system and various phase-change heat exchanger, were seemed to be insufficient. 6) A review of recent studies on duct system shows that the methods for circuit analysis, and flow balancing have been presented. Researches on ventilation are focused on the measurement of ventilation efficiency, and variation of ventilation efficiency with ventilation methods by numerous experimental and numerical studies. Furthermore, many studies have been conducted in real building in order to estimate indoor thermal environments. Many research works to get some information for cooling tower design have been performed but are insufficient. 7) A review on the recent studies on architectural thermal environment and building mechanical systems design shows that thermal comfort analysis is sitting environment, thermal performance analysis of Korean traditional building structures., and evaluation of building environmental load have been performed. However research works to improve the performance of mechanical system design and construction technology were seemed to be insufficient.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.6
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• pp.427-446
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• 2008

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2006 has been accomplished. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro heat exchanger and siphon cooling device using nano-fluid. Traditional CFD and flow visualization methods were still popular and widely used in research and development. Studies about diffusers and compressors were performed in fluid machinery. Characteristics of flow and heat transfer and piping optimization were studied in piping systems. (2) The papers on heat transfer have been categorized into heat transfer characteristics, heat exchangers, heat pipes, and two-phase heat transfer. The topics on heat transfer characteristics in general include thermal transport in a cryo-chamber, a LCD panel, a dryer, and heat generating electronics. Heat exchangers investigated include pin-tube type, plate type, ventilation air-to-air type, and heat transfer enhancing tubes. The research on a reversible loop heat pipe, the influence of NCG charging mass on heat transport capacity, and the chilling start-up characteristics in a heat pipe were reported. In two-phase heat transfer area, the studies on frost growth, ice slurry formation and liquid spray cooling were presented. The studies on the boiling of R-290 and the application of carbon nanotubes to enhance boiling were noticeable in this research area. (3) Many studies on refrigeration and air conditioning systems were presented on the practical issues of the performance and reliability enhancement. The air conditioning system with multi indoor units caught attention in several research works. The issues on the refrigerant charge and the control algorithm were treated. The systems with alternative refrigerants were also studied. Carbon dioxide, hydrocarbons and their mixtures were considered and the heat transfer correlations were proposed. (4) Due to high oil prices, energy consumption have been attentioned in mechanical building systems. Research works have been reviewed in this field by grouping into the research on heat and cold sources, air conditioning and cleaning research, ventilation and fire research including tunnel ventilation, and piping system research. The papers involve the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies on indoor air quality took a great portion in the field of building environments. Various other subjects such as indoor thermal comfort were also investigated through computer simulation, case study, and field experiment. Studies on energy include not only optimization study and economic analysis of building equipments but also usability of renewable energy in geothermal and solar systems.

• Parasites, Hosts and Diseases
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• v.55 no.4
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• pp.399-408
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• 2017

A survey was performed to know the recent infection status of digenetic trematode metacercariae in clams and oysters from 4 sites in western coastal regions of the Republic of Korea (=Korea). Four species of clams (Mactra veneriformis, Ruditapes philippinarum, Cyclina sinensis, and Saxidomus purpuratus) were collected from Taean-gun, Chungcheongnam-do (Province), Buan-gun (County) and Gochang-gun, Jeollabuk-do, and oysters, Crassostrea gigas, from Shinan-gun, Jeollanam-do were transferred to our laboratory on ice and examined by the artificial digestion method. The metacercariae of Himasthla alincia were detected in 3 species of clams, M. veneriformis, R. philippinarum, and C. sinensis from the 3 surveyed areas. The positive rate and the mean density per clam infected were 98.9% (30.8 metacercariae) in M. veneriformis, 60.0% (5.0) in R. philippinarum, and 96.0% (28.4) in C. sinensis. The positive rate (mean density) of Acanthoparyphium tyosenense metacercariae in M. veneriformis was 50.0% (2.1) from Taean-gun and 70.0% (2.8) from Gochang-gun. The metacercariae of Parvatrema spp. were detected in M. veneriformis and R. philippinarum from Taean-gun and Gochang-gun; the positive rate (mean density) was 63.3% (4,123) and 50.0% (19) in M. veneriformis, and 6.7% (126) and 100% (238) in R. philippinarum from the 2 regions, respectively. The metacercariae of Gymnophalloides seoi were detected in all 30 oysters from Shinan-gun, and their average density per oyster was 646. From the above results, it has been confirmed that more than 3 species of metacercariae are prevalent in clams from the western coastal regions, and G. seoi metacercariae are still prevalent in oysters from Shinan-gun, Jeollanam-do, Korea.

• The Korean Journal of Community Living Science
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• v.19 no.3
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• pp.335-351
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• 2008

Adequate nutrients intake and regular eating habit are so important for the students to develop physical and mental health, and they contribute significantly for the development of intellectual capacity. The intake of simple sugar contained in the processed foods is known to have been related not only with such physical problems as obesity and diabetes but also with hyperactivity during growing period. This study analysed the effects of carbohydrate processed snacks on the middle school students' emotional intelligence and intended to demonstrate the correlation and the influence of the foods. The subjects of this study were 476 the 1st grade middle school students sampled from two public middle schools of Gyeonggi Province, Korea. Questionnaire contained 47 questions including the kinds of sugar containing processed foods, the frequency of intake, the frequency of normal diet, and the emotional test. All data obtained in this study were processed by SAS 8.2 program. 77.9% of the students had snacks more than once a day and the favored foods were in the order of bread, cookies, fruit, milk and dairy products, flour foods, ramen and ice cream. Less of the sugar contained processed snacks consumed high emotional intelligence showed(p<0.001). And low intake of carbohydrate processed snacks linked with having more regular meals and the higher levels of emotional intelligence. There was no gender difference in consuming simple sugar containing processed foods, however, out of these foods, carbonated drinks, ramen and pizza affected significantly the emotional intelligence of the male students. It was found that sugar contained processed snacks affect the eating habits like meal skipping and the emotional intelligence. It is determined that the effects of carbohydrate processed snacks on emotional intelligence can not be denied.

• Journal of Nutrition and Health
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• v.9 no.4
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• pp.28-35
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• 1976

To know changes of the food preferences and the practice of pica during pregnancy, ninety two women in the latter half of pregnancy were interviewed in April, 1976 at ten medical centers in Seoul. They were average 27.1 years old, and mostly middle class. 83.7% of the total subjects felt the changes of food preferences due to pregnancy within the first trimester. 60.9% had vomiting as well as losing their appetite and 17.3% vomited three or more times daily which might induce difficulties of water and electrolytes balance in body. The preferences about foods, the taste of foods, and various dishes cooked during morning sickness were changed significantly and showed in lower scores of likes and higher scores of dislikes than those before pregnancy. Particularly, cooked rice and kimchi indicated the increase of more than 50% in dislikes. The preferences after the morning sickness were turned back to those before pregnancy. Desire for water through foods like soft drinks, juice, ice cream, and gamju and salty foods seemed to be spontaneous during pregnancy. A majority of the subjects had three meals and no snack had included more snacks instead of meals during losing appetite and thereafter, had more frequent meals and snacks. Superstitions about chicken, squid, and cuttlefish for pregnant women were prevalent. 11.9% tabooed chicken because of harm for fetus. On the contrary, intended higher inclusions of milk, meat and dried small sardines would be helpful to satisfy the increased recommended allowances of calcium and protein for them. The practice of pica was found in 5.4% and rice was the only real item mentioned. Pica such as amylophagia or geophagia often reported in the U.S. was not answered in this study.

• Korean Journal of Community Nutrition
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• v.17 no.3
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• pp.302-311
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• 2012

The purpose of this study was to provide preliminary data for better safety control over children's preference foods sold in school stores. The survey was conducted from June to July 2009, to collect 749 types of children's preference foods sold in 150 middle and high school stores nation-wide excluding Jeju Island and general and nutrition information were analyzed. Out of 749 types of snack food items, 689 and 602 snacks were sold at high school and middle school stores respectively. Among children's preference foods, cookies, bread, and ice-cream were the main items. Among them, 98% of snacks were domestic products and the price range of each individual snacks were mostly between 600 and 900 won. 27.8% of children's preference foods sold were found to be in the high calorie/low nutrition food group. Even though the proportion of candy and fruit/vegetable beverages sold were not high, their proportion in high calorie/low nutrition snack group were higher than 68.1%. Among the children's preference foods sold in middle and high school stores, carbonated drinks and ramen were continuously sold in certain middle and high schools, even though sales were prohibited. This study concludes that government, corporations and retailers should work together in developing healthier children's snack distribution environment. In addition, dairy products, which take up 15% of children's preference food, should be diversified to meet their nutrient requirements.

• Korean Journal of Community Nutrition
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• v.18 no.3
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• pp.257-268
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• 2013

The purpose of this study was to evaluate nutrient intake and meal variety with breakfast eating in Korean adolescents using data from the 2008-2009 National Health and Nutrition Examination Survey. The analysis included 1245 adolescents aged 12 to 18 years. The subjects were divided into two groups according to breakfast skipping (BS: breakfast skipping, n = 235, BE: breakfast eating, n = 1110). The BS group was significantly higher in its frequency of eating soda drinks, instant noodle, and ice cream than the BE group. The BS group consumed significantly lower quantities of plant calcium and plant protein per 1,000 kcal compared to the BE group. Also the intake of cereal and vegetables in the BS group was significantly lower than those in the BE group, however, the intake of beverage in the BS group was significantly higher than that in the BE group. The average number of foods of the BE and BS groups were 29.50 and 25.85, respectively and revealed a statistical significance (p < 0.0001). The snack intake and % energy from snack intake of the BS group were significantly higher than those of the BE group. Also, the fasting blood glucose concentrations were significantly higher in the BS group compared to the BE group. In conclusion, adolescents who skip breakfast may have lower meal variety and higher blood glucose concentrations. Therefore, in support of proper dietary management, it is necessary to promote and encourage breakfast eating.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.305-310
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• 2002

The performance of 7 sugary (su) and 12 shrunken-2 (sh2) sweet com hybrids which are commercially grown in the United States was tested in Korea. The 100-seed weight of su hybrids (16.5-23.6 g) was much heavier compared to that of sh2 hybrids (10.9-17.5 g). The germination rate of su and sh2 hybrids at $25^{\circ}C$ ranged 93.3-100% and 86.7-98.9%, the emergence rate of su and sh2 hybrids in cold test ranged 78.9-97.8% and 62.2-97.8%, and field emergence rate of su and sh2 hybrids ranged 74.4-100.0% and 79.9-98.2%, respectively. In su hybrids, there was a significantly positive correlation between germination rate at $25^{\circ}C$ and emergence rate in cold test or early growth. In contrast, in sh2 hybrids seed weight was positively correlated with early plant growth, while not with the germination rate at $25^{\circ}C$ or emergence rate in cold test and field. Most sh2 hybrids produced larger and more marketable ears compared to su hybrids although there were significant differences among the hybrids in the same genotype. At harvest (24 days after pollination) soluble solids content of su hybrids (24.3-27.1 Brix %) was much higher than that of sh2 hybrids (13.8-18.0 Brix %), while total sugars of sh2 hybrids (21.4-28.6% on the dry weight basis) was much higher compared to su hybrids (2.4-15.9%). Considering germination and emergence rates, marketable ear production, and total sugar content, 'GCB 70' and 'Sweet Satin' in su hybrids and 'Ice Queen', 'Aspen', 'Sweet Magic', 'Bandit', 'Xtrasweet 82', 'Aspen', and 'Cambella 90' in sh2 hybrids performed better than other hybrids.

• Journal of the Korean Home Economics Association
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• v.37 no.3
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• pp.175-191
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• 1999

The purpose of this study was to investigate the eating behavior and life habits of kindergarten children 5 to 7 years old in Chuncheon area. This study was conducted in December, 1996. Anthropometric indices(height, weight, skinfold thickness, mid-arm circumference) were measured and body mass index(BMI), Rohrer index, arm fat area were calculated to estimate children’s body fatness. Also the eating behavior and life habits were determined tv using questionnaire method. The results were as follows: Body fat rate of the children was almost normal according to Rohrer index and BMI. There was significant difference in birth weight between male and female. The problems of the eating behavior were frequent skipping breakfast and eating-out. The rate of the children who took snacks 2 times a day was 46.9％. Most children tended to take sweet snacks such as ice-cream, chocolates, cookies, and they tended to prefer meats and fishes to vegetables. The rate of breast feeding was 28.3％ and the rate of weaning foods prepared at home was 61.1%. Many children preferred indoor activities such as watching TV, toy furniture play, building block to outdoor activities such as roller-skating, cycling, jogging in their spare time. The rate of the children who took exercise regularly was 15％. Children tended to eat kimbap, fried chicken, ramyeon more frequently in various instant foods. The intake rates of fruit juice and barly tea were relatively high and children's favorite fruits were watermelon and mandarin orange. From this results, skipping breakfast, frequent eating-out and the monotony of food preference appears to cause imbalance in nutrient intakes of the children and to have bad influence on children’s health. Accodgingiy, the comprehensive nutrition education and proper modification program should be needed for the children and their parents to correct the eating behavior and life habits. The reasonable exercise programs are needed to motivate outdoor activities of the children, and the importance of breast feeding and weaning foods should be emphasized to lactating women and pregnant women.