• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.15 no.4
• /
• pp.255-262
• /
• 1982

The data of 37 oceanographic stations in the coastal sea of Jeju island are compiled in terms of temperature, salinity, dissolved oxygen, silicate, nitrate and phosphate to analyge the chelnical characteristics in this region. This work was carried out during June, 1951. The concentrations of nutrients in the layer more than 50 m are generally 0.5-3 times larger than the surface layer. Each constituents in this layer are as follows: temperature ranged 11.8 to $15.4^{\circ}C$ and salinity, 33.8 to $34.8\%_{\circ}$; and also dissolved oxygen and slicate are 5.2 to 5.6ml/l and 5.6 to $9.0{\mu}g-at/l$, respectively. And nitrate and phosphate ranged 1.0 to $6.0{\mu}g-at/l$ and 0.1 to $0.5{\mu}g-at/l$, respectively. The coastal sea of Jeju island is divided into two parts in chemical view point : one is the southeastern sea of Jeju island under the influence of the Tsushima Current, md the other is the northeastern sea of Jejo island under the influence of the Yellow Sea Bottom Cold Water and the south coastal water of Korea. The north-western sea of Jeju island had relatively a cold (about $13^{\circ}C$) and low saline water (about $34\%_{\circ}$), and dissolved oxygen was higher than in the neibouring waters. It seems that in the southern area between Moseulpo and Seogwipo of Jeju island, two different Ivater masses are complicately intermixed and a tidal front is formed.

• Journal of the Korean Chemical Society
• /
• v.45 no.2
• /
• pp.131-137
• /
• 2001

The protonation and stability constants of complexation of Zn(II), Cd(II) and Pb(II), Hg(II) ion with sulfur-containing podand ligands such as tri(phenylthio-2-ethy1)amine (Podand N$_1$S$_3$)tetra(phenylthio-2-ethyl)ethylenediamine (Podand N$_2$S$_4$) , tris(1-benzylaminoethyl)amine (Podand N$_4$) have been determined by potentiometric titration in 95% methanol at variable temperatures, From these studies, we observed that podand N$_4$ ligand showed the largest protonation constant. Protonation constant, stability constant, enthalpy, entropy of Zn(II), Cd(II) and Pb(II), Hg(II),ions increased with the following order podand N$_1$S$_3$$_2$S$_4$$_4$.

• Journal of the Korean Chemical Society
• /
• v.37 no.11
• /
• pp.937-942
• /
• 1993

Enzyme electrodes for amperometric measurement of ammonia was prepared by immobilization of L-glutamate dehydrogenase on an Immobilon-AV Affinity membrane and attachment to a glassy carbon electrode. Reduced nicotinamide adenine dinucleotide (NADH) was used as the electroactive species. The electrochemical oxidation of NADH was monitored at ＋1.0 volt vs. Ag/AgCl. Response was linear from $4.0\;{\times}\;10^{-5}\;to\;4.0\;{\times}\;10^{-4}$ M. The detection limit was 2.0 ${\times}\;10^{-6}$ M. Response time, the optimum pH and life time of enzyme immobilized membrane were 2 min, pH 7.3∼7.6 (Dulbecco's buffer solution) and about 25 days respectively. When the enzyme electrode was applied to the $NH_4^+$ determination with amperometric method, other physiological materials had no interference.

• Journal of Educational Research in Mathematics
• /
• v.27 no.1
• /
• pp.51-67
• /
• 2017

Analogical reasoning is a mathematically useful way of thinking. By analogy reasoning, students can improve problem solving, inductive reasoning, heuristic methods and creativity. The purpose of this study is to analyze the analogical reasoning of preservice mathematics teachers while constructing quadratic curves defined by eccentricity. To do this, we produced tasks and 28 preservice mathematics teachers solved. The result findings are as follows. First, students could not solve a target problem because of the absence of the mathematical knowledge of the base problem. Second, although student could solve a base problem, students could not solve a target problem because of the absence of the mathematical knowledge of the target problem which corresponded the mathematical knowledge of the base problem. Third, the various solutions of the base problem helped the students solve the target problem. Fourth, students used an algebraic method to construct a quadratic curve. Fifth, the analysis method and potential similarity helped the students solve the target problem.

• 한국해양학회지
• /
• v.30 no.3
• /
• pp.163-169
• /
• 1995

A total of 190 phytoplankton taxa was identified in southern waters of the East Sea of Korea in May 1988, July 1989 and November 1991. Leptocylindrus danicus, Nitzschia pungens and Bacteriastrum delicatulum were the dominant species in spring. In summer, Skeletonema costatum was dominant all around the study area but Chaetoceros socialis and Rhizosolenia alata f. gracillima were locally dominant. On the other hand, the dominant species in autumn shifted to Chaeotoceros socialis, Nitzschia delicatissima, Nitzschia sp. and Gymnodinium sp. The average species diversities of the phytoplankton community were low in spring, summer and autumn, being 1.24, 1.69 and 2.12 respectively. The result of cluster analysis in summer suggested that the surface water of this study area could be divided into three phytohydrographic regions which consisted of the oceanic water region affected by Tsushima current, the east Korean neritic water region and the proper water region adjacent to Ulleung island. Compared with the surface phytohydrographic regions, one more region might be recognized at the 40m depth waters. It was appeared in the middle of study area and seemed to be affected by both Tsushima current and water mass of 10$^{\circ}C$ located deeper than 50m.

• Aerospace Engineering and Technology
• /
• v.8 no.2
• /
• pp.61-67
• /
• 2009

This paper proposes an on-board orbit data generation algorithm for geostationary satellites. The concept of the proposed algorithm is as follows. From the ground, the position and velocity deviations with respect to the assumed reference orbit are computed for 48 hours of time duration in 30 minutes interval, and the generated data are up-loaded to the satellite to be stored. From the table, three nearest data sets are selected to compute position and velocity deviation for asked epoch time by applying $2^{nd}$ order polynomial interpolation. The computed position and velocity deviation data are added to reference orbit to recover absolute orbit information. Here, the reference orbit is selected to be ideal geostationary orbit with a zero inclination and zero eccentricity. Thanks to very low computational burden, this algorithm allows us to generate orbit data at 1Hz or even higher. In order to support 48 hours autonomy, maximum 3K byte memory is required as orbit data storage. It is estimated that this additional memory requirement is acceptable for geostationary satellite application.

• Journal of the Korean Home Economics Association
• /
• v.42 no.5
• /
• pp.39-52
• /
• 2004

The purpose of this study was to evaluate the meal pattern and the nutritional balance in university foodservices of Seoul. The survey was conducted using a questionnaire with 317 students at five different cafeterias that served 23 meals. We weighed all the meals offered by the university foodservices, separated the foods, and calculated their nutritional content using a computer program $\ulcorner$DS24$\lrcorner$. We also checked the dishes and those amount students consumed from the menu. The results of this study is summarized as follows. : 1) The most prevalent menu patterns included rice, soup, two side dishes, and kimchi. 2) Most nutrient contents per meal in a given menu was lower than one third of the recommended dietary allowance(RDA). 3) The mean energy content for the amount of rice that was served was 399㎉, for the side dish, it was 107㎉, and for the kimchi, it was 9.9㎉. 4) The number of total dishes and side dishes was five and two, respectively. The dietary variety score was 16.7, and the dietary diversity score was 3. 5) The mean energy intake by students at self-operated managements were 545㎉, and at one contracted management, the energy intake were 494㎉. Both of them did not serve enough to meet one third of the RDA. Nutrient adequacy ration(NAR) was 0.4∼0.9, and Index of nutritional quality(INQ) was above 0.9 for most nutrients with the exception of calcium and vitamin B$_2$.

• Journal of Nutrition and Health
• /
• v.35 no.5
• /
• pp.558-570
• /
• 2002

This study was performed to develop an index assessing the overall diet quality for Korean. The study subjects consisted of preschool children (PC), elementary school children (EC), high school students (HS), college students (CS), and adults over 30 years old living Seoul and the surrounding areas. The subjects over 30 years old were classified to 30-49 years, 50-69 years, and over 70 years. A dietary survey was conducted using 24-hour recall method and data were collected from 2392 people. Newly developed Korean diet quality index (KDQI) was an index assessing the overall diet quality from the view point of balance. KDQI was based on the nutritional problems of Koreans, dietary risk factors for chronic degenerative diseases, 5 major food groups, and dietary guidelines. The ten components of KDQI were vegetables, fruits, dairy products, dietary variety score, calcium intake, iron intake, energy intake, fat intake, and cholesterol intake. The full score of each component was 10 points and the score of KDQI was calculated by summing the scores of the 10 components. When the KDQI was applied to this study subjects, the distribution of subjects KDQI scores was similar to normal distribution. Mean score of KDQI was 56.0 and the range of the mean by age was from 45.7 for the subjects over 70 years old to 60.7 for the elementary school children. The components which composed the lowest three means were dairy intake, fruit intake, Ca intake in most age groups. Mean score of DVS was one of the highest three but not for the subjects over 50 years old. After subjects with KDQI score over 70 were classified to higher poop and those with KDQI score under 40, to lower group, nutritional characteristics were compared. Energy contributions of carbohydrate, proteins, and fit, percentages of RDA for major nutrients, and dietary diversity scores were more adequate in the higher poop than in the lower group. The lower poop had more risks for chronic degenerative diseases. According to the results, KDQI was valid index to assess the overall diet quality and it could be used to detect risk group for malnutrition and chronic degenerative diseases.

• Journal of Nutrition and Health
• /
• v.33 no.8
• /
• pp.882-889
• /
• 2000

This study was conducted to examine contribution of specific foods to absolute intake and between-person variation in nutrients consumed by 2037 adults living in Korean rural area using one day 24-hour recall method. To measure contribution of food to absolute nutrient intake, all foods consumed were ranked by percentages calculated as the sum of the nutrient intake contributed by a given food divided by the total nutrient intake from al categories. To assess between-person variability in nutrient intake, stepwise multiple regression analysis was used with total nutrient intake from al foods as the dependent variable and the nutrient amount from each of all foods as independent variables. The kind and the number of foods necessary to account for the variation in nutrient intake among persons varied significantly depending on the nutrient. The nutrients contributing more than 80% of total intake with a few number of food items were ${\beta}$-carotene(ll), vitamin C(15) and vitamin A(16). Foods sometimes overlooked as important sources were found in some instances to be quantitatively important to population intake. Even though rice and Korean cabbage kimchi do not contain much nutrients in quantity, they made a major contribution to most nutrient intake of subjects because of large serving size and high frequency of intake. The food items and contributing order for between person variance was different from those of absolute intake. A large fraction of the variability of nutrient intake in this population was explained by a small number of foods. Fewer foods were required to explain a given proportion of the between-person variance in intake than to account for the same proportion of the popylation\`s total intake. These data may be useful in the development of dietary assessment instrument and in nutrition education. (Korean J Nutrition 33(8) : 882-889, 2000)

• Korean Journal of Community Nutrition
• /
• v.14 no.5
• /
• pp.576-589
• /
• 2009

The purpose of this study was to analyze the status of school foodservice facilities, utilities and equipment & sanitary education in provinces, This study was carried out from September 2008 until December 2008 and is targeted towards schools' dietitians that work at schools with school foodservice. 1,623 schools participated in this research and Kangwondo, Choongchungdo including the metropolitan area with frequent occurrence of food bone disease were the targets of this research. The regional distribution of this research is as follows; 377 schools in Seoul, 648 schools in Gyeonggido, 160 schools in Kangwondo, 438 schools in Choongchungdo equaling 1,623 schools in total. And out of the total 1,623 schools, 815 (50.2%) were elementary schools and 808 (48.8%) were middle and high schools (p < 0.001). Most of the elementary schools, excluding 4 schools, were self-operated. In the case with middle and high schools, 81.5% (513 schools) were self-operated and 18.4% (295 schools) were contracted. When dealing with the sanitation management of school foodservice in Kangwondo and Seoul, elementary schools were less equipped with equipment and facilities than middle and high schools which proved that they were in need of improvements (p < 0.01). Schools with self-operated foodservice, in particular, were in need of preparation zone improvements. 52.3%~88.0% of stainless equipment such as utensils, spoons/chopsticks, subsidiary food tray, and food trays were sterilized by dryers. Work tables, vegetable slicers, and mincers were chemically sterilized and plastic materials were sterilized by ultraviolet rays. Data from newspapers, Internet and TV are collected beforehand and then an annual hygiene educations plan for employees are put together. Hygiene education for employees are carried out monthly through oral method.