• Korean Journal of Soil Science and Fertilizer
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• v.7 no.1
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• pp.35-42
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• 1974

From the results of countrywide two year N. P. K simple trial with newly bred IR 667-Suwon 214 and leading local varieties for comparison soil productivity (yield without fertilizer) and fertilization productivity (yield increase with fertilizer) were investigated. 1. IR667 showed higher yield than leading local by 19% in 1971 and by 12% in the year of low temperature stress, 1972. High yielding capacity of IR667 was attributed to greater number of spikelet per panicle. The coefficient of variation in yield was smaller in IR667 but the leading locals showed higher yield in 23(1971) and 30% (1972) of the fields. 2. IR667 required more nitrogen, especially phosphorus and potassium. Fertilization efficiency (yield increment per unit fertilizer) in IR667 was-about 4kg higher in nitrogen but smaller in phosphorus and almost the same in potassium. 3. Soil productivity was higher in IR667 but percent contribution of soil productivity to total productivity (field productivity) was lower. 4. Percent contribution of fertilization productivity to field productivity was 19 to 33, of which 5 was due to phosphorus and potassium. 5. The greater the soil productivity, the greater the field productivity becomes, but the much greater the percentage contribution of soil productivity becomes. 6. Fertility saturation point at which fertilization efficiency is nil, was propoesd as a soil productivity (or field productivity) limit.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.3
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• pp.124-132
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• 2010

In spite of the global importance of primary production of phytoplankton, some primary production data in Korean coastal waters still need to be better processed. The daily rates of water column primary production is generally estimated by integrating the primary production per unit volume over time and depth, but efforts for time integration algorithm have been conducted insufficiently. In this study a mathematical equation evaluating daily primary production integrated over time of a day is proposed and the effectiveness of the model is tested on Saemangeum Lake. The daily primary productions computed with the proposed equation were nearly the same with the results numerically integrated by substituting solar irradiance data. It was suggested that better estimation of primary production would be obtained by using monthly or weekly means of solar irradiance rather than more variable daily data. Because of the vertically heterogenous distribution of phytoplankton, it's hard to integrate the equation over depth to give the daily rates of primary production per unit area of water surface. However, the problem would be solved if, after the vertical distribution of phytoplankton was classified into several patterns and reduced to mathematical formula, every composite function of time integrated equation and chlorophyll distribution equation was integrated successfully.

• 한국생태학회:학술대회논문집
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• 1998.05a
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• pp.55-55
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• 1998

• 한국해양학회지
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• v.26 no.3
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• pp.242-254
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• 1991

Southern sea of Korea was investigated for primary productivity during four scientific cruises of Korea Ocean research and Development Institute. Frontal structure appeared to be an important physical characteristic in enhancing the phytoplankton production in the study area. Relatively high productivity was occurred near the front between Tsushima Warm Current Water and Coastal Waters of China continent in March 1990 and in November 1989, and near the front between Tsushima Warm Current Water and Korean coastal Water in April 1989. In August 1988 high productive zone was limited to the tidal front off the southwestern coast of Korea. Nutrient supply related to the frontal structure might play a dominant role in increasing the primary productivity but mechanisms of nutrient enrichment are not clear. Average column productivity showed its maximum in April 1989 (1727 mgC/m$^2$/day). In the costal Waters of the china Continent incident light may be an important factor in regulating the regulating the phytoplankton production because of low light penetration rate resulting from high turbidity.

• School Mathematics
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• v.10 no.4
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• pp.583-601
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• 2008

The creative productivity is regarded as an essential factor to perform the gifted education. While it is very important to cultivate and to expand a creative productivity through mathematically problem solving in gifted education, we have difficulties in actual education of the (mathematically) gifted, even are there few researches/studies which deal with teaching and guiding the creative problem solving in mathematically gifted education, it is hard to find a guideline that provides proper ways (or directions) of learning-instruction and evaluation of the mathematically gifted. Therefore in this study, the researcher would provide a learning-instruction model to expand a creative productivity. The learning-instruction model which makes the creative productivity expanded in mathematically gifted education is developed and named MG-CPS(Mathematically Gifted-Creative Problem Solving). Since it reflected characteristics of academic- mathematical creativity and higher thinking level of the mathematically gifted, this model is distinguished from general CPS. So this model is proper to provide a learning experience and instruction to the mathematically gifted.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2002.05a
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• pp.59-59
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• 2002

• 한국해양학회지
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• v.26 no.3
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• pp.223-241
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• 1991

In order to study the formation and structure of tidal fronts and their influence on the distribution and productivity of phytoplankton in the outer of Kyonggi Bay, analyses on the water temperature data from 1977 to 1986 and 3 surveys from 1981 to 1986 were carried out in the mid0eastern coast of the Yellow Sea. Temperature gradients and dissolved oxygen gradients were implied that the tidal fronts are formed at the outer of the Kyonggi Bay along the western side of Tae-An peninsula from spring to summer. the formations of tidal fronts in this study area influence the distribution of phytoplankton and primary productivity. The standing stocks, chlorophyll concentrations and primary productivity of phytoplankton in the frontal area are higher than those of the outer stratified waters and the inner coastal mixed waters. These high production in the frontal area are resulted from good light condition and rich nutrient within the water columns. With a boundary of frontal area, there are relatively high chlorophyll concentrations and primary productivity in the coastal mixed waters while there are low chlorophyll concentrations and relatively high primary productivity in the stratified waters. These relatively high primary productivity in the outer area are resulted from the high potential production by nanoplankton in the surface layer and the high production of tychopelagic diatoms under the thermocline with the deep transparency.

• Proceedings of the Malacological Society of Korea Conference
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• 2001.11a
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• pp.35-36
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• 2001

해양의 유기물 합성의 95%를 담당하는 식물프랑크톤은 해양 먹이연쇄의 1차 생산자로서 이들을 여과 섭식하는 이매패류는 식물프랑크톤의 분포나 양에 따라 그 생산이 좌우된다. 그러나 이 식물프랑크톤의 분포는 동일한 해역이라도 영양염류, 수온, 태양광선의 세기와 해수면에 입사된 광선이 해수 중에서 소멸되는 정도 등에 따라 생선속도가 달라지므로 동일해역에서도 분포의 변이가 매우 심하다. 기초생산력의 차이는 굴 성육에 관계되므로 여과섭식성 이매패류 양식장의 생산성 평가의 기초자료로 이용되고 있다(배 등, 1978; 이 등, 1991). 이 연구는 북만의 기초생산력을 조사하여, 다른 해역과 비교하고 먹이생물의 생산능력에 의한 굴양식장 수용력을 검토하는 자료로 제공하였다.

• Korean Journal of Environmental Biology
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• v.20 no.2
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• pp.146-151
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• 2002

The primary productivity and physicochemical factors were surveyed seasonally in Gangjin bay from February to October in 1998. The determination of the Primary Productivity Was performed in Situ by isotope-method using NaH/sup 14/CO/sub 3/. The range of primary productivity was 2.78 mgC m/sup -3/ hr/sup -1/-4.92 mgC m/sup -3/ hr/sup -1/ according to seasons. The primary productivity showed the highest value in summer, followed by those of winter, autumn and spring. The primary productivities of station 1, 2 which are located the upper area, were lower than those of station 3, 4, 5 and 6. The correlations showed that the primary productivity correlated with chlorophyll a, underwater light intensity but reversely correlated with suspended solids. These results suggested that the primary productivity in Gangjin Bay was mainly influenced by the inflow of freshwater from Tamjin River.

• Korean Journal of Environmental Biology
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• v.17 no.4
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• pp.459-465
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• 1999

This work focused on the effects of the timing and the frequency of shoot cutting to maximize the productivity and the nutrient removal of three emergent macrophytes, Phragmites communis, Zizania latifolia and Typha angustifolia in natural wetlands. Shoot cutting significantly enhanced biomass production and resulted in more nitrogen and phosphorus removal from water in these three experimental species, compared to those of control. However, the frequency and the timing of shoot cutting, and the enhancement ratio were different among three species. For Phragmites stands, the highest productivity was 1.9 times of control in June treatment of the first year experiment, while 1.3 times in May treatment of the second year experiment. Zizania and Typha stands were both 1.2 times of control in August treatment and June and August treatment. Calculating the total annual removal rate of nitrogen and phosphorus based on the highest productivities among treatments, in Phragmites stands, 2.0 times of nitrogen and 1.8 times of phosphorus were removed in the first year, and both 1.4 times in the second year experiment. Likewise, for nitrogen and phosphorus; 2.4 and L.8 times in Zizania stands, and 1.8 and 1.9 times in Typha stands were removed. Overall, these results suggested that cutting treatment of shoots be effective. Thus, shoot cutting of two times during a growing season were recommended to maximize the effects: that is, in May or June, and October for Phragmites stands, and in August and October fur Zizania and Typha stands.