• Korean Journal of Ecology and Environment
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• v.34 no.1 s.93
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• pp.30-44
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• 2001

In this study limnological characteristics of Lake Juam was surveyed from June 1993 to May 1994 in order to provides important information regarding water resources. Secchi disc transparency, epilimnetic chlorophyll a (chi-a), total nitrogen (TN), total phosphorus (TP) concentration and primary productivity were in the range of $2.0{\sim}4.5\;m$, $0.9{\sim}13.6\;mgChl/m^3$, 0.78$\{sim}$2.32 mgN/l, $11{\sim}56\;mgP/m^3$, $270{\sim}2.160\;mgCm^{-2}\;day^{-1}$, respectively. On the basis of TP, Chl-a and Secchi disc depth, the trophic state of Lake Juam can be classied as mesotrophic lake. The phosphorus inputs from non-point sources are concentrated in heavy rain episodes during the monsoon season. As a result, phosphorus concentration are higher in summer than in winter. TP loading from the watershed were estimated to be $0.9\;gPm^{-2}yr^{-1}$, which correspond to a boundary of the critical loading ($1.0\;gPm^{-2}yr^{-1}$) for eutrophication. From the results of the algal assay, both phosphous and nitrogen act as limiting nutrients in algal growth. The seasonal succession of phytoplankton community structure in Lake Juam was similar to that observed in other temperate lakes. Diatoms (Asterionella formosa and Aulacoseira granulate var. angustissima)fujacofeira BraHuJafa uar. aHgusHrsiaia) weredominant in spring and winter, cyanobacteria) were dominant in warm season. The organic carbon, nitrogen and phosphorus content of lake sediment were $9.5{\sim}14.0\;mgC/g$, $1.01{\sim}1.82\;mgN/g$ and $0.51{\sim}0.65\;mgP/g$, respectively. The allochthonous organic carbon loading from the watershed and autochthonous organic carbon loading by primary production of phytoplankton were determined to be 1,122 tC/yr and 6,718 tC/yr, respectively. To prevent eutrophication of Lake Juam, nutrient management of watershed should be focus on reduction of fertilizer application, proper treatment of manure, and conservation of topsoil as well as point source.

• Journal of the Korean earth science society
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• v.32 no.7
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• pp.832-859
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• 2011

The importance of scientific education on accurate oceanic currents and circulation has been increasingly addressed because the currents have played a significant role in climate change and global energy balance. The objectives of this study are to analyze errors of the oceanic current maps in the textbooks, to discuss a variety of error sources, to suggest how to produce a unified oceanic current map of the East Sea for the students. Twenty-seven textbooks based on the 7th National Curriculum were analyzed and quantitatively investigated on the characteristics of the current maps by comparing with both the previous literature and up-to-date scientific knowledge. All the maps in the textbooks with different mappings were converted to digitalized image data with Mercator mapping using geolocation information. Detailed analysis were performed to investigate the patterns of the Tsushima Warm Current (TWC) in the Korea Strait, to examine how closely the nearshore branch of the TWC flows along the Japanese coast, to scrutinize the features of the offshore branch of the TWC south of the subpolar front in the East Sea, to quantitatively investigate the northern range of the northward-propagating East Korea Warm Current and its latitude turning to the east, and lastly to examine the outflow of the TWC near the Tsugaru Strait and the Soya Strait. In addition, the origins, southern limits, and distances from the coast of the Liman Current and the North Korea Cold Current were analyzed. Other erroneous expressions of the currents in the textbooks were presented. These analyses revealed the problems in the present current maps of the textbooks, which might lead the students to misconception. This study also addressed a necessity in a bridge between scientists with up-to-date scientific results and educators who needed educational materials.

• Korean Journal of Environmental Agriculture
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• v.32 no.3
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• pp.224-230
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• 2013

BACKGROUND: Perchlorate(${ClO_4}^-$) is an anion that is extremely water-soluble and environmentally stable. It mostly exists in the form of sodium perchlorate, ammonium perchlorate and potassium perchlorate which are used in rocket fuels, propellants, ignitable sources, air bag inflation systems and explosives. Perchlorate can be taken into the thyroid glands and interfere with iodide uptake. The determination of perchlorate in agricultural products is important due to its potential health impact on humans. The objective of this study was to determine the perchlorate concentrations in the samples of various agricultural products and soils. METHODS AND RESULTS: In this study, samples of cereal(Rice, Barley, Corn, Bean), vegetable(Spinach, Lettuce, Sesame, Chives, Chili, Pumpkin, Tomato), fruit(Apple, Pear, Tangerine, Grape) were analyzed for perchlorate contents. Perchlorate concentrations were analyzed by liquid chromatography-tandem mass spectrometry. The results showed that agricultural products respectively contained perchlorate concentrations in the range of : cereals N.D.~$7.46{\mu}g/kg$, vegetables $0.52{\sim}23.06{\mu}g/kg$, fruits $0.19{\sim}2.66{\mu}g/kg$. Bioconcentration factor was in the order of : vegetables > cereals > fruits. Bioconcentration factor was highest follwed by Sesame 37.88, Corn 21.51, Spinach 10.57, Tangerine 4.39, Chives 2.89 and Lettuce 1.90. The recoveries of perchlorate from spiked agricultural products and soils ranged from 87.72~111.26% and 102.09~111.23%. CONCLUSION(S): The health risk assessment results obtained in this study are lower than the RfD(Reference Dose, 0.0007 mg/kg/body weight/day) value as suggested by the Integrated Risk Information System(US IRIS). Our results indicate that, people currently exposed to perchlorate from agricultural products consumption are considered as safe.

• The Journal of Engineering Geology
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• v.22 no.1
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• pp.67-81
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• 2012

The physical, chemical, and biological properties of clogging materials formed within groundwater wells in the Mt. Geumjeong area, Busan, Korea, were characterized. The particle size distribution (PSD) of clogging materials was measured by a laser analyzer. XRD, SEM, and TEM analyses were performed to obtain mineralogical information on the clogging materials, with an emphasis on identifying and characterizing the mineral species. In most cases, PSD data exhibited an near log-normal distribution; however, variations in frequency distribution were found in some intervals (bi-or trimodal distributions), raising the possibility that particles originated from several sources or were formed at different times. XRD data revealed that the clogging materials were mainly amorphous ironhydroxides such as goethite, ferrihydrite, and lapidocrocite, with lesser amounts of Fe, Mn, and Zn metals and silicates such as quartz, feldspar, micas, and smectite. Reddish brown material was amorphous hydrous ferriciron (HFO), and dark red and dark black materials were Fe, Mn-hydroxides. Greyish white and pale brown materials consisted of silicates. SEM observations indicated that the clogging materials were mainly HFO associated with iron bacteria such as Gallionella and Leptothrix, with small amounts of rock fragments. In TEM analysis, disseminated iron particles were commonly observed in the cell and sheath of iron bacteria, indicating that iron was precipitated in close association with the metabolism of bacterial activity. Rock-forming minerals such as quartz, feldspar, and micas were primarily derived from soils or granite aquifers, which are widely distributed in the study area. The results indicate the importance of elucidating the formation mechanisms of clogging materials to ensure sustainable well capacity.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.1
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• pp.10-19
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• 2000

Due to the urbanization, concentrated population, and limited land exploitation in the modern society, the environment surrounding that we live in is getting polluted more and more, and it has become hard even to let urban children experience the nature. This research was conducted to help people recognize the importance of our natural resources through the environmental education of elementary school and to use school's practical open-space for the Indigenous Plants education. The results of this study are as follows : First, the status of a plant utilization in our institutional education : There were 362 species totally of 124 species of Trees, 156 species of Herbs, 63 species of Crops, and 19 species of Hydrophytes which appear in the elementary school text book. Of all, the most frequently appearing species of tree were the Malus pumila var. dulcissima, Pinus densijlora, Citrus unshiu, Diospyros kaki. Second, the effect of plant education using the land around schools : The result of research on the open-space of the 19 elementary schools located in Mapo-gu showed that most of the species planted are the Juniperus chinensisrose, Hibiscus syriacus. Pelargonium inquinans in the order of size, and the plants appearing in text book were grown in the botanical garden organized in 7 schools. Especially most of the Indigenous Plants were being planted in botanical garden, and Pinus densijlora, Abeliophyllum distichum, Polygonatum var. plurijlorum, Liriope platyphylla and so on. Last, the result of this research on recognition of Environment, Planting education and Indigenous plants : It showed that educational necessity of students and teachers about environment and Indigenous Plants was more than 80%. The management of botanical garden was conducted by some teachers and managers. The results of this study suggested that we needed the reconstruction of curriculum, the efficient application of plant education for effectiveness of using school environment and monitoring continually and construction information sources for the better environment education in the elementary schools.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.466-476
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• 2006

The objective of this study was to compare and analyze the acceptability and consumption attitude for soy foods between Korean and Canadian university students as young consumers. This survey was carried out by questionnaire and the subjects were n=516 in Korea and n=502 in Canada. Opinions for soy foods in terms of general knowledge were that soy foods are healthy (86.5% in Korean and 53.4% in Canadian) or neutral (11.6% in Korean and 42.8% in Canadian), dairy foods can be substituted by soy foods (51.9% in Korean and 41.8% in Canadian), and soy foods are not only for vegetarians and milk allergy Patients but also for ordinary People (94.2% in Korean and 87.6% in Canadian). In main sources of information about soy foods, the rate by commercials on TV, radio or magazine was the highest (58.0%) for Korean students and the rate by family or friend was the highest(35.7%) for Canadian students. In consumption attitude, all of Korean students have purchased soy foods but only 55.4% of Canadian students have purchased soy foods, and soymilk was remarkably recognized and consumed then soy beverage and margarine in order. 76.4% of Korean students and 65.1% of Canadian students think soy foods are general and popular and can purchase easily, otherwise, in terms of price, soy foods were expensively recognized as 'more expensive than dairy foods' was 59.1% (Korean) and 54.7% (Canadian), and 'similar to dairy foods' was 36.8% (Korean) and 39.9% (Canadian). Major reasons for the rare consumption were 'I am not interested in soy foods' in Korean students (27.3%) and 'I prefer dairy foods to soy foods' in Canadian students (51.7%). However, consumption of soy foods in both countries are very positive and it will be increased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.6
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• pp.496-502
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• 2004

The development of sesame varieties which contain high contents of lignan compounds has been progressed in Korea. This study was carried out to get the basic information for the breeding of high quality sesame varieties and the development of health functional food sources using lignan compounds from sesame. The contents of sesamin and sesamolin were $4.08\pm1.74$ and $2.47\pm0.68mg/g$, respectively, from sesame cultivated in 2002 and those were $4.08\pm1.51$ and $2.48\pm0.69mg/g$, respectively, from sesame cultivated in 2003. The content of sesamine was high in the order of Danbaek (6.22 mg/g), Seongbun (5.94 mg/g), Namda (5.83 mg/g), and Naman (5.59 mg/g) producted in 2002 and Seongbun (6.27 mg/g), Dasak (5.53 mg/g), Danbaek (5.50 mg/g), chinbaek (5.45 mg/g), and Seodun (5.41 mg/g) producted in 2003. The content of sesmoline was high in the order of Hwangbaek (3.27 mg/g), Seongbun (3.26 mg/g), Annam (3.22 mg/g), Hanseom (3.17 mg/g), and Danbaek (3.16 mg/g) producted in 2002, and Seongbun (3.21 mg/g), Seodun (3.14 mg/g), Pungan (3.10 mg/g), Naman (3.09 mg/g), and Danbaek (3.04 mg/g) producted in 2003. The contents of sesamin and sesamolin of Yangbaek, which has used as a standard variety for sesame breeding, were relatively lower than in any other varieties. These resluts suggest that Yangbaek is not the proper variety as a standard variety for development of high quality sesame. In conclusion, proper good variety as a standard variety for sesame breeding must be determined after careful consideration on the major quality factors including crude oil and lignan compounds as well as agricultural characteristics to develop high quality sesame varieties containing high contents of lignan compounds.

• Journal of Technology Innovation
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• v.22 no.1
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• pp.149-175
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• 2014

This study analyzed the effect of corporate innovation strategies on patent production and ultimately on technological change and new product development of firms in South Korea. The intent was to derive efficient strategies for enhancing technological performance of the firms. For the empirical analysis, three sources of data were combined: four waves of the Human Capital Corporate Panel Survey (HCCP) data collected by the Korea Research Institute for Vocational Education and Training (KRIVET), corporate financial data obtained from the Korea Information Service (KIS), and corporate patent data provided by the Korean Intellectual Property Office (KIPO). The patent production function was estimated by zero-inflated negative binomial (ZINB) regression. The technological performance function was estimated by two-stage regression, taking into account the endogeneity of patent production. An ordered logit model was applied for the second stage regression. Empirical results confirmed the critical role of corporate innovation strategies in patent production and in facilitating technological change and new product development of the firms. In patent production, the firms' R&D investment and human resources were key determinants. Higher R&D intensity led to more patents, yet with decreasing marginal productivity. A larger stock of registered patents also led to a larger flow of new patent production. Firms were more prolific in patent production when they had high-quality personnel, intensely investing in human resource development, and adopting market-leading or fast-follower strategy as compared to stability strategy. In technological performance, the firms' human resources played a key role in accelerating technological change and new product development. R&D intensity expedited new product development of the firm. Firms adopting market-leading or fast-follower strategy were at an advantage than those with stability strategy in technological performance. Firms prolific in patent production were also advanced in terms of technological change and new product development. However, the nexus between patent production and technological performance measures was substantially reduced when controlling for the endogeneity of patent production. These results suggest that firms need to strengthen the linkage between patent production and technological performance, and take strategies that address each firm's capacities and needs.

• Journal of Nutrition and Health
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• v.10 no.2
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• pp.59-70
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• 1977

This study was designed to evaluate the changes and improvements in the Korean diet during the last thirty years (since independence in 1945), and to make recommendations for the improvement of their nutritional status, consequently contributing to the physical and mental welfare of the Korean people. The results and recommendations are as follows: 1. The total calorie and carbohydrate intake decreased by $8{\sim}12%$ in the 1970's, as compared with the 1940's and the 1950's. 2. The intake of calcium and vitamiu A increased $30{\sim}50%$ and $20{\sim}60%$ respectively in the 1960's and 1970's as compared with the 1940,s. But this intake level is still lower than the RDA values. 3. The vitamin C intake was somewhat higher in the mountainous and farming areas than in urban areas. 4. In the 1970's, the decrease of untriend intake due to seasonal variation was marked especially for protein, niacin, vitamin $B_1$, and vitamin C. 5. The consumption of protein foods (meats and legumes) increased in an amount of $15{\sim}36g$ per day. There was a marked increase in the intake of meat in farming areas and of milk in urban areas in the 1970's. This increased intake of animal proteins is a very desirable dietary change. 6. The cereal consumption was lowest in urban areal, but there was a general decrease in the intake of the cereal group in the entire area in the 1970's. For the farmers, the intake of cereal food decreased most, from 750 g to 576 g, but cereals still composed a high proportion of the entire diet. 7. Fruits and vegetables showed the highest intake for the urban people, as expected. For the whole area, this food group showed an increase of 8.7% in the 1970's, as compared with the 1960's. 8. The gradual ihcrease in the intake of the fats and oil group was a desirable dietary change. but the absolute amount was too low. 9. A 7% increase in height and a 9% incrrase in weight for growing children and adolescents was observed in the 1970's as compared with the 1940's, but several kinds of deficiency diseases, such as nutritional anemia and dental caries were still apparent in many areas. 10. To improve cur food life and to cope with food shortages faced in Korea, an efficient and nationwide nutrition education program should be implemented. This would maximize efficiency of intake from the limited food sources for a balanced diet. 11. As it is of utmost importance to provide growing children with a desirable physical, sccial mental, and especially nutritional environment, a well-planned and organized school feeding program should be practiced widely and efficiently. 12. Young mothers and pregnant women should be educated on the importance of their children's nutrition, especially for the critical fetal and infancy periods. 13. More thorough and continuous nutritional survey studies on the changes in dietary patterns for the entire nation should be pursued, evaluated and documented. This would Provide a good information guide for future nutritional study programs. 14. It is the nutritionistist's strong desire that national leaders, especially decision makers recognize the fact that improvement of the nutritional status of the People is one of the most economic and preventative ways of improving their physical and mental health. This is closely related to the economic development and strength of the nation.

• The Journal of the Acoustical Society of Korea
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• v.13 no.6
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• pp.75-82
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• 1994

The ray paths and travel times of sound wave in the ocean depend on the physical properties of the propagating media. Ocean Acoustic Tomography(OAT), which is inversely estimate the travel time variations between fixed sources and receivers the physical properties of the corresponding media can he understood. To apply ocean survey technology by using the OAT, the tomographic procedure requires forward problem that variation of the travel times be identified with the variability of the medium. Also, received signals must be satisfied the necessary conditions of ray path stability, identification and resolution in order for OAT to work. The canonical ocean has been determined based on the historical data and its travel time and ray path are used as reference values. The sound speed of canonical ocean in the East Sea is about 1523 m/s at the surface and 1458 m/s at the sound channel axis(400m). Sound speeds in the East Sea are perturbed by warm eddy whose horizontal extension is more than 100 km with deeper than 200 m in depth scale. In this study, an acoustic source and receiver are placed at the depth above the sound channel axis, 350 m, and are separated by 200 km range. Ray paths are identified by the ray theory methed in a range dependent medium whose sound speeds are functions of a range and depth. The eigenray information obtained from interpolation between the rays bracketing the receiver are used to simulate the received signal by convolution of source signal with the eigenray informations. The source signal is taken as a 400 Hz rectangular pulse signal, bandwidth is 16 Hz and pulse length is 64 ms. According to the analysis of the received signal and identified ray path by using numerical model of underwater sound propagation, simulated signals satisfy the necessary conditions of OAT, applied in the East Sea.