• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.245-253
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• 1979

Trimethylamine and dimethylamine contents of salted, hot-air dried, sun dried and boiled-dried samples of three commercial fishes, common mackerel, gizzard-shad and sardine, were analyzed and quantitatively compared at two different temperature conditions. The formation of both secondary amines was more rapid at $25^{\circ}C$ than at $10^{\circ}C$. And the content of dimethylamine in small sardine was comparatively higher than that in the other samples at both temperatures. Residual amounts of trimethylamine oxide of Halted common mackerel, gizzard-shad and boiled-dried small sardine were relatively higher than those of the other samples. Trimethylamine contents of sun dried samples were relatively higher than in the other samples, while those of boiled-dried small sardine was comparatively lower than those of the others. Dimethylamine content of sun dried samples were higher than those of the other samples, whereas those of boiled-dried small sardine and salted common mackerel were comparatively lower than those of the other samples.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.4
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• pp.308-316
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• 1987

The flying fish, Prognichthys agoo, is widely distributed in the coastal waters of south-eastern Korea. On July 14, 1986, mature adults of flying fish were captured from U-do, Cheju-do. The eggs were stripped and fertilized by the wet method on the ship. The mature eggs are demersal and adhesive with 30-40 filaments. The egg diameter varied from 1.42 to 1.58 mm. The water temperature throughout incubation ranged from 23.70 to $27.82^{\circ}C$, and salinity was maintained at $30.75-33.76\%_{\circ}$. The hatching took place in 174 hours after fertilization. The newly hatched larvae measured 4.75-5.25 mm in total length possessing yolk sac and about 45-46 myotomes. The larvae cultured for ten days after hatching reached 11.45-12.60 mm in total length and entered the juvenile period of life. Twenty days after hatching, the juveniles measured 20.01 mm in mean total length, and the scales were formed behind the pectoral fin.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.561-569
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• 2012

To evaluate the bacteriological water quality in Yongnam-Gwangdo, located in western Jinhae Bay, seawater samples were analyzed using sanitary indicator bacteria at 57 sampling stations. According to survey results from January 2007 to December 2009, the range of the geometric mean and the estimated 90th percentile for coliforms and fecal coliforms in the samples were <1.8-16.5 and 1.8-246.8 MPN/100 mL and <1.8-7.1 and 1.8-74.8 MPN/100 mL, respectively. The samples, including those taken from stations located in Wonmunman, Gwangdo, and Dangdong, showed high levels of microbial contamination caused by the climate and weather patterns in the marine environment. The bacteriological water quality in the area met Korean criteria for a designated shellfish growing area for export and National Shellfish Sanitation Program criteria for an approved shellfish growing area, except at station #49. A total of 24 direct pollution sources were discharged into the shellfish growing area. The radius of impact was calculated for each pollution source to assess the effect on the shellfish growing area. The calculated radius of impact for most of the pollution sources was below 300 m. However, the radius of impact for the combined pollution sources in Kyeonnaeryang was 93-1973 m. There were significant differences between the calculated closed sea area and actual monitoring results. The closed sea area values calculated from the fecal coliform load in drainage water tended to be higher than the actual monitoring results. Tidal currents and environmental factors such as salinity, water temperature, sunlight, and microbiological factors affect the survival of fecal indicator bacteria in seawater.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.5
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• pp.438-444
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• 2012

This study was investigated the effect of gamma irradiation (GI) on the shelf-life and quality improvement of squid sundae (a traditional Korean sausage) stored at room temperature after 0 (control), 10 and 20 kGy doses of irradiation. The total viable cells decreased with increasing irradiation dose, and no viable cells were detected with the doses of 20 kGy. There were no significant changes in pH compared to the control. The volatile basic nitrogen (VBN) and thiobarbituric acid reactive substance (TBARS) values of GI (20 kGy) squid sundae were significantly lower than those of the control. In addition, the induction period for the GI (20 kGy) squid sundae measured by the Rancimat method was higher level than that of the control. In a sensory evaluation, there were no significant differences between the control and GI samples during storage.

• Journal of the Korean Association of Geographic Information Studies
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• v.1 no.2
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• pp.44-55
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• 1998

This study was carried out to investigate the feasibility of OTEC(Ocean Thermal Energy Conversion) operation, in the East Sea of Korea. Accumulated cruise data of NFRDI (National Fisheries Research and Development Institute) over the period 1966~1995 were used to locate appropriate spot by season as well as by latitude which would show the difference at least $15^{\circ}C$ or more between the surface layer and each depth of 50, 100, 150, 200, 250, 300, 400 and 500m. Our results showed that the coastal areas of Pohang city met the requirement of more than $20^{\circ}C$ difference for OTEC plant from August to October. In contrast, in case that $15^{\circ}C$ would be possible thermal difference to operate OTEC plant, most coastal areas in the East Sea including Pohang from June to December are potential candidates for this future energy source. Therefore, we present in this paper the first option to locate the best place for OTEC plant operation using Geographical Information System (GIS), which is currently used for multi-dimensional space analysis.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.4
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• pp.94-100
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• 2008

Recently, global warming for climate system is a crucial issue over the world and it brings about severe climate change, abnormal temperature, a downpour, a drought, and so on. Especially, a drought over the earth surface accelerates desertification which has been advanced over the several years mainly originated from a climatic change. The objective of this study is to detect variation of vegetation water condition around China and Mongolia desert by using satellite data having advantage in observing surface biological system. In this study, we use SPOT/VEGETATION satellite image to calculate NDWI (Normalized Difference Water Index) around study area desert for monitoring of status of vegetation characteristics. The vegetation water status index from remotely sensing data is related to desertification since dry vegetation is apt to desertify. We can infer vegetation water status using NDWI acquired by NIR (Near infrared) and SWIR (Short wave infrared) bands from SPOT/VGT. The consequence is that NDWI decreased around desert from 1999 to 2006. The areas that NDWI was decreased are located in the northeast of Mongolian Gobi desert and the southeast of China Taklamakan desert.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.3
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• pp.12-24
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• 2013

Eradication of endemic malaria was declared in mid 1980's in Korea, but the number of malaria cases has been oscillating for the past 10 years since the reemergence of the disease in early 1990's. The occurrence of malaria has been concentrated near the demilitarized zone(DMZ), and the regional characteristics of the disease are evident. Considering the spatial variations of malaria incidence across the high-risk areas, the hotspot of the disease, it seems that the occurrence of the disease is influenced by the natural and human environment in the region. Malaria is an infectious disease that is transmitted to humans by the bites of vector-mosquitoes carrying malaria parasites, and it depends on specific climatic and sociodemographic factors. Malaria transmission is highly climate-sensitive, and temperature is the most important component. In addition, human contacts with vector-mosquitoes and the distance between human residence and mosquito habitats are crucial conditions determining malaria incidence rates. The present study aimed to test a hypothesis that the spatial characteristics of malaria incidence depended on local climatic conditions, relative proportions of mosquito habitats, and the distance between mosquito habitats and human residence using meteorological and satellite-based land cover data.

• Journal of the Korean Chemical Society
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• v.45 no.5
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• pp.442-447
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• 2001

The charge-transfer compound (OMTTF)AuCl$_4$ was prepared from the direct reaction of octamethylenethiafulvalene (OMTTF) with HAuCl$_4{\cdot}xH_2$O in THF. (OMTTF)$_2PtCl_4$, (OMTTF)_2IrCl_6{\cdot}2H_2$O, and (OMTTF)Os$Cl_5{\cdot}THF$ were also formed using $H_2PtCl_6{\cdot}xH_2O$, $H_2IrCl_6{\cdot}xH_2O$ and $H_2OsCl_6$, respectively. The prepared compounds were characterized by magnetic (EPR, magnetic susceptibility), spectroscopic (IR, UV-Vis), electrochemical (CV) methods, and the powdered electrical conductivity measurement. The powdered electrical conductivities at room temperature were ~$10^{-7}S{\cdot}cm^{-1}$. The experimental results show that $OMTTF^+$ monocation radicals exist in all of the prepared compounds. The redox potential of OMTTF supports that $OMTTF^+$ is relatively stable. The magnetic properties indicate that there are significant magnetic interactions between the localized odd electrons on the central metal (Ir and Os) ions and the odd electrons resided on $OMTTF^+$ cation radicals in both (OMTTF) $_2IrCl_6{\cdot}2H_2O$ and (OMTTF)$OsCl_5{\cdot}THF$.

• Journal of the Korean Chemical Society
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• v.45 no.5
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• pp.481-490
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• 2001

The purpose of this study was to find out the problems on the fractional distillation experiments in the middle school science textbooks based on the 6th curriculum and to suggest an efficient experiment method for the middle school students. The first step was the classification of the experiments in 8 science textbooks according to heating apparatus and liquid mixtures. The second step was doing each experiment 3 times followed by the experimental process in the textbooks. The third step was developing the alternative experiments for solving the problems found in the second step. The heating method used in the alternative experiments were direct heating, oil bath, and heating mantle. The results of the second step showed that the direct heating experiment of branched round flask was more close to the theoretical prediction than the experiment of water bath heating of branched test tube. Also the direct heating experiment of thermally insulated branched round flask was better than the result of the experiment which was not insulated. The results of the third step showed that the experiment using heating mantle regulated heating power by observing the temperature of distillate gave the closest result to the theoretical prediction. From the above results, it is concluded that the experiment using branched test-tube with water bath heating is not adequate for the fractional distillation and an alternative experiment using insulated branched round flask with heating mantle regulated heating power during experiment is recommended.

• Journal of the Korean Chemical Society
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• v.43 no.5
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• pp.564-577
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• 1999

The purpose of this study is to help an improvement of conceptional learning about the properties of gas based on molecular kinetics for secondary school students and to help an improvement of teaching method for reducing misconceptions regarding the molecular kinetics in gas phase for teachers. The subjects of this study were l00 students of 9th grade and 150 students of 11th grade students. The results showed that students had various misconceptions about the properties of gas. The major misconceptions are as follows. First, the energy is released due to the collision of the molecules, and also the direction of action of pressure is related to the direction of gravity. Second, as molecule is heated, the size of molecule is increased, and the molecule is more active because the number of moIecules is increased. Third, the pressure is reduced because of decreasing the temperature at the higher altitude and the pressure of gas molecuIes is inversely proportional to the collision number of gas molecules. Forth, the numbers of molecules of two different molecules in two same containers differ because the size of molecules differ each other. The results suggest that these problems ought to be addressed in chemistry textbooks and in the classroom teaching of chemistry. If teachers are more aware of students' misconceptions they wilI be better able to remove them.