• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.25 no.3
• /
• pp.55-66
• /
• 2020

Near-inertial waves (NIW) which are primarily generated by wind can contribute to vertical mixing in the ocean. The energetic NIW can be generated by typhoon due to its strong wind and preferable wind direction changes especially on the right-hand side of the typhoon. Here we investigate the generation and distribution of NIW using the output of a real-time ocean forecasting system. Five-year model outputs during 2013-2017 are analyzed with a focus on cases of energetic NIW generation by the passage of three typhoons (Halong, Goni, and Chaba) over the East Sea. Calculations of wind energy input (${\bar{W}}_I$), and horizontal kinetic energy in the mixed layer (${\bar{HKE}}_{MLD}$) reveal that the spatial distribution of ${\bar{HKE}}_{MLD}$, which is strengthened at the right-hand side of typhoon tracks, is closely related with ${\bar{W}}_I$. Horizontal kinetic energy in the deep layer (${\bar{HKE}}_{DEEP}$) shows patch-shaped distribution mainly located at the southern side of the East Sea. Spatial distribution of ${\bar{HKE}}_{DEEP}$ shows a close relationship with negative relative vorticity regions caused by warm eddies in the upper layer. Monthly-mean ${\bar{HKE}}_{MLD}$ and ${\bar{HKE}}_{DEEP}$ during a typhoon passing over the East Sea shows about 2.5-5.7 times and 1.2-1.6 times larger values than those during summer with no typhoons, respectively. In addition, their magnitudes are respectively about 0.4-1.0 and 0.8-1.0 times from those during winter, suggesting that the typhoon-induced NIW can provide a significant energy to enhance vertical mixing at both the mixed and deep layers during summer.

• Korean Journal of Agricultural Science
• /
• v.2 no.1
• /
• pp.61-100
• /
• 1975

This study has been made to find out the possibilty of successfully using the following $K_2O$ recommended equation $K_2O\;kg/10a=(Ko/\sqrt{Ca+Mg}-Ks/\sqrt{Ca+Mg})sqrt{Ca+Mg}.\;47.\;B\;D$. where $Ko/sqrt{Ca+Mg}=0.03518+0.0007658\;Sio_2/O.M$. $K_Ssqrt{Ca+Mg}$=Exchangeable K me/100g/$\sqrt{Total\;soluble(Ca+Mg)me/100g\;in\;Soil}$ B. D. =Bulk density of top soil, when the dose of Nitrogen for rice is estimated from the following equation: $N\;kg/10a=(4.2+0.096\;SiO_2/O.M).F$ where $F=0.907+0.263x-0.013x^2$ $SiO_2/O.M=(available\;SiO_2=ppm)/(organic\;matter\;%)$in soil For this. two field experiments. one in sandy and the other in clay paddy soil. have been conducted using 3 levels of wollastonite (0, 500, 100kg/10a) as main treatments; 3 levels of $K_2O$ application were used as sub-plots. These were as follows : (1) 8kg of $K_2O$/10a regardless of the K activity-$K/\sqrt{Ca+Mg}$; (2) kg of $K_2O$/10a estimated from the above equation. and (3) same as (2) above plus additional 30% of $K_2O$. The dose of N kg/ 10a was determined from the above equation based on the value of $SiO_2$/O.M. ratio in each treatment. There were three replications. The leading variety of rice in Chung Chong Nam Do area. Akibare (introduced from Japan) was used. The data obtained. through soil and plant analysis and growth and yield observations. have been throughly examined to attain the following summarized conclusions. 1. The nitrogen dose. estimated from the above equation. was in excess for optimum growth of the rice variety Akibare; indicating the necessity of modification onthe value of "F" or the constants in the equation. The concept of using $SiO_2$/O.M. in the equation was shown to be applicable. 2. The dose of potash. estimated from the respective equation given above. also was in excess of the rice requirements indicating the necessity of minor change in the estimation of $Ko/\sqrt{Ca+Mg}$ value and some great modification in the calculation of $Ks/\sqrt{Ca+Mg}$ value for the equation; however the concept of using $K/\sqrt{Ca+Mg}$ as a basis of $K_2O$ recommendation was shown to be quite reasonable. 3. It was found. from the correlation study using the data of paddy yield and amount of $K_2O$ absorbed by rice plants that the substitution of the value of $Ks/\sqrt{Ca+Mg}$ in the equation for the vaule $Ks/\sqrt{Ca+Mg}=0.037+0.78K\;me/100g$ soil was much more applicable than using the value calculated from the data of soil and wollastonite analysis.

• Korean Journal of Soil Science and Fertilizer
• /
• v.9 no.3
• /
• pp.211-220
• /
• 1976

The objective of this paper is to summarize and disicuss the results of studies for the prediction of fertilizer demands up to the year of 2000, from the agromic biew points. 1. The approximated demands of fertilizers figured out from the view point of nutrient requirement and fertilizer efficiency of major crops are 1,162,000M/T (N;554,100 M/T, $P_2O_5$; 360,100 M/T and $K_2O$, 247,000 M/T) at 1980, 1,471,400 M/T (N: 694,800 M/T, $P_2O_5$;465,400M/T and $K_2O$ ;311,200 M/T) at 1990 and 1,764,00 M/T (N;812,500 M/T, $P_2O_5$; 592,300 M/T and $K_2O$;359,200 M/T) at 2000${\cdots}{\cdots}$ (Approximation I) 2. Upon the basis of approximation on the yield levels of major crops per unit area and on the expansion of arable land, the demands of fertilizers at the years of 1980, 1990 and 2000 are predicted as 1,149,300 M/T (N;603,700 M/T $P_2O_5$; 305,500 M/T and $K_2O$, 240,100 M/T) 1,551,100 M/T(N:814,700M/T, $P_2O_5$;412,300 M/T and $K_2O$;324,00 M/T) and 2,253,800 M/T (N;1,183,800M/T, $P_2O_5$; 586,400M/T and $K_2O$, 470,900 M/T), respectively${\cdots}{\cdots}$(Approximation II) 3. When the recent relationships between the increases in yeid of major crops and the amounts of fertilizers for those crops per unit area are brought into consideration for the estimation of future demands of fertilizers, the predicted demands at the years of 1980, 1990 and 2000 are 1,287.600 M/T (N;677,100 M/T, $P_2O_5$; 342,000 M/T, and $K_2O$;268,500 M/T), 2,085,600M/T (N;1,096,700 M/T, $P_2O_5$;533,900 M/T, and $K_2O$;435,000 M/T and 3,380,600 M/T (N;1,777,800M/T, $P_2O_5$;897,800M/T and $K_2O$;705,000M/T) respectively (Approximation III) 4. Approximation I will be closer estimate under such condition that only rice will maintain self suficiency and other food crops will be covered by domestic production by around 50 percent, which is not desirable situation. 5. When higher self suficiency leveles of major food crops are sought through the introduction of improved varieties and expansion of cropping area and arable land by increased land utilization and reclamation of hillside land and tidal land, the Approximations II and III will become close to reality, If improved fertilizers and improved method of fertilizer applications are widely applied at the farmers fields to increase the fertilizer efficiency the former will be closer figure, if not, the latter may be better estimates.

• The Korean Journal of Ecology
• /
• v.17 no.3
• /
• pp.299-310
• /
• 1994

Intraspecific clonal interactions have important influences on a population structure of the cellular slime mold (CSM). This study was to investigate whether or not evolutionary change in a population could be induced by clonal competition, and to elucidate how various clones in a population evolve in a homogeneous environment of laboratory culture. The characteristic clones of Polysphondylium pallidum which had different resource consumption rates (RCR) and mating types I and II were selected for study. Investigation was conducted for 4 experimental time interval $(T_0-T_4)$; one experimental time interval took almost 10-14 days from inoculation to havest of fruiting bodies. Two sets of 50 clones were cultured from 50 clones at To, and RCR variations of the population were compared between $(T_0\;and\;T_4)$ for each set of clones. Each clone of the CSM had a diverse resource consumption rate, or growth rate, in a homogeneous and limited Cerophyl agar plate despite the passage of 48-56 generations from the beginning of the experiment. Diverse clones with different growth rate could coexist in one site of the homogeneous agar plate as well as heterogeneous soil microenvironment. When there was high clonal diversity of RCR, a clone in a population had high chances to encounter other clones with resultant increased clonal competition. In one set, 26 of 37 clones of mating type I were changed to mating type Il for the 4 experimental time intervals, which indicated that the rate of competitive exclusion among clones during total experiment from $(T_0\;to\;T_4)$ was 0.703. In another set, 31 of 37 clones of mating type I were changed to mating type II , having the rate of competitive exclusion 0.838. The frequency of each of mat~ng types changed by 0.93-1.29% in each successive generation. The competitive exclusion among clones occurred by 1.26-1.75% when approximately $2.6{\times}10^8$ bacterial cells were provided as food and thereafter one generation of myxamoebae of CSM elapsed at room temperature. This finding implicated that in the vegetative state of P, pallidurn there was 1.26-1.75% probabil~ty of evolutionary change per generation changing from one clone to another clone.

• Journal of Environmental Policy
• /
• v.5 no.1
• /
• pp.45-70
• /
• 2006

China has achieved great economic growth above 9% annual since it changed to more of a market economy system by its reform and open-door policy. At the same time, China has experienced severe ecological deterioration, such as air and water pollutions caused by its rapid urbanization and industrialization. China is now confronted with environmental pollution and ecological deterioration at a critical point, at which economic development in China is limited. Moreover, environmental problems in China have become a lit fuse for social fluctuation beyond pollution problems. The root and background of environmental problems in China, firstly, are its government's lack of understanding of these problems and incorrect economic policies affected by political and ideological prejudice. Secondly, the plundering of resources, 'the principle of development first' which didn't consider environmental sustainability is another source of environmental deterioration in China. In addition, a huge population and poverty in China have increased the difficulty in solving its environmental problems, and in fact have accelerated them. The Chinese government has established many environmental laws and institutions, increased environmental investments, and is enlarging the participation of NGOs and the general public in some limited scale to solve its environmental problems. However, it has not obtained effective results because of the lack of environmental investments owing to the government's limit of the development phase, a structural limit of law enforcement and local protectionism, and the limit of political independency in NGOs and the lack of public participation in China. It seems that China remains in the stage of 'economic development first, environmental protection second', contrary to its catch-phrase of 'the harmony between economic development and environmental protection'. China is now confronted with dual pressure both domestically and abroad because of deepening environmental problems. There are growing public's protests and demonstrations in China in response to the spread of damage owing to environmental pollution and ecological deterioration. On the other hand, international society, in particular neighboring countries, regard China as a principal cause of ecological disaster. In the face of this dual pressure, China is presently contemplating a 'recycling economy' that helps sustainable development through the structural reform of industries using too much energy and through more severe law enforcement than now. Therefore, it is desirable to promote regional cooperation more progressively and practically in the direction of building China's ability to solve environmental problems.

• Journal of Korean Home Economics Education Association
• /
• v.17 no.3 s.37
• /
• pp.83-96
• /
• 2005

To assess the food intake and diet quality of high school students who live in Chuncheon area, a dietary survey using 24-hour recall method was conducted with 318 subjects. $71.4\%$ of total food intake was in the form of plant foods and the rest on the form of animal food. Diet quality was assessed by food group pattern, dietary diversity score(DDS), and dietary variety score(DVS). When counting the major food groups consumed, $37.1\%$ of subjects had a DDS of 3 and $48.4\%$ of subjects had a DDS of 4. When investigating the consumption pattern of the major five food groups, only $14.5\%$ of subjects consumed foods from all five groups. On average, subjects habitually consumed 26.7 different foods daily, with the mean score of diet variety for males (27.3) being significantly higher than for females (25.8) . Correlation coefficients between nutrient adequacy ratio (NAR) and DVS ranged from r=0.39 for vitamin $B_2$ to r=0.61 for phosphorus. NAR also improved as the number or foods or rna groups consumed increased (p<0.001). Associations between the NAR and high level of DVS was more positive than those between the NAR with DDS. When assessing the dietary quality of subjects using DDS and DVS, many people appeared not to have a desirable food intake. Therefore, to lead them to have nutritionally balanced diet, educating students and their parents on nutrients and suggesting guidelines for a desirable diet is considered to be essential so that they can intake from all of major food group and have various foods in their diet.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2007.05a
• /
• pp.308-311
• /
• 2007

황해의 25개 조사정점의 표층수에 대한 해양환경요인 및 식물플랑크톤 현존량의 월별 조사결과를 종합하여 주성분분석(PCA)을 실시한 결과 주성분 I에서는 변화를 26.6% 설명할 수 있으며, 이중 질산질소가 가장 많이 기여하였고, 이어서 용존무기질소, 규산규소, 수온, 용존산소, 암모니아질소 순으로 기여 하고 있었다. 주성분 II에서는 20.3%를 설명 할 수 있으며, 이중 용존산소가 가장 많이 기여하였고 그 외 엽록소 a, 수온, 염분, 규산규소, 식물플랑크톤 현존량 순으로 기여 하였다. 주성분 III에서는 15.1%를 설명 할 수 있으며, 이중 인산인이 가장 많이 기여하였고 그 외 염분, 아질산질소, 수온, 용존산소, 질산질소, 용존무기질소 순으로 기여하였다. PCA에 이용된 항목 중 부유물질은 제외한 모든 항목은 주성분 I, II, III에 5%이하 유의수준에서 의미 있는 상관성이 있었다. 주성분 I은 질산성질소, 용존무기질소, 규산규소, 인산인과는 긍정적인 상관성(p<0.0001)을 갖고, 수온, 암모니아질소와는 부정적인 상관성을 보였다(p<0.001). 주성분 II에서는 용존산소, 엽록소 a, 식물플랑크톤 현존량은 긍정적 상관성을 나타내었고, 수온, 염분, 규산규소와는 부정적인 상관성을 보였으며(p<0.0001), 주성분 III에서는 염분, 수온, 질산질소, 용존무기질소, 식물플랑크톤 현존량과는 긍정적인 상관성(P<0.0001)을 나타내었고 인산인, 아질산질소, 용존산소는 부정적인 상관성을 나타내었다 (p<0.01). 공간적인 분포특성은 조사정점에 따라 항목별 결과에 대한 분산이 커서 일정한 특성을 도출하기가 어려운 상태이나 대체로 PCA II축을 기준으로 상부인 $1/4{\sim}2/4$분면에 북부와 중부의 조사정점이 위치하고 음의 방향인 $3/4{\sim}4/4$분면에 중부와 남부의 조사정점이 위치하고 있어 북측의 307선과 308선 및 중부의 309선과 310선 그리고 남측의 311선과 312선으로 구분되어지는데 그 중에서 태안반도의 연안역인 307선의 03점은 계절에 변화가 가장 커서 분산의 폭이 심한 상태로서 다른 조사정점들과 구분되어진다. 전반적으로 북측해역에서는 용존산소, 엽록소 a, 식물플랑크톤 현존량이 남측해역에 비해 상대적으로 많은 반면, 남측해역은 수온과 염분 및 규산규소가 높은 상태이었다. 북쪽인 307선과 308선은 연안역과 외해에서 상대적으로 영양염류가 높았으며, 중부인 309선과 310선은 연안역과 준 외해역인 07점과 09점에서 영양염류가 높았었고, 남부 해역인 311선과 312선에서는 연안역에서 영양염류가 상대적으로 높은 경향을 나타내었다. 즉 황해 동부는 연안역에서는 조석간만의 차가 심하고, 새만금 및 시호호등과 같은 대규모의 간척 매립으로 육상의 오염원이 자정작용을 거치지 못하고 직접 연안으로 유입되고 있는 실정이다. 또한 10여 년 전부터 육지의 모래부족으로 다량의 바다 모래가 채취되어 왔고 그 량이 점차 증가추세이며, 중부외해역에서는 각종 폐기물 투기로 점차 영양염류의 부하량이 증가되고 있어 특히 질소계와 인의 영양염류 농도가 높아지고 있는 추세이다. 시간적 변동특성은 전반적으로 순환하는 형태를 유지하고 있다. 2005년 2월에는 질산질소, 용존무기질소, 규산규소, 인산인, 용존산소가 높았었으며 4월로 접어들면서 항목 간에 분산되는 경향을 보이면서 수온, 엽록소 a 및 식물플랑크톤이 증가 하면서 해역에 따라 좌우로 분산되는 경향을 나타내었고 6월에는 아질산질소를 제외한 영양염류가 감소하는 경향을 보였다. 8월에는 6월에 비해 수온이 높아지고 규산규소, 질산질소, 용존무기질소 등이 약간 증가추세이었으며 10월로 접어들면서 증가추세가 더 높아졌었고 12월에는 질산질소, 용존무기질소, 규산규소, 인산인, 용존산소가 높아졌었다. 2006년 4월에는 2005년 4월에 비해 수온, 엽록소 a, 식물플랑크톤의 현존량이 높아져서 전년 동시기와 약간 다른 양상을 보이고 있었다. 즉 동계인 2월을 시작으로 반 시계 또는 시계 방향으로 순환하는 형태를 유지하고 있으며, 4월은 2개년 비교해 보았을 때 해마다 해양환경에 따라 그 순환 정도 및 형태가 다를 것으로 추정된다.

• Korean Journal of Ecology and Environment
• /
• v.41 no.3
• /
• pp.382-394
• /
• 2008

The objective of this study was to analyze temporal trends of water chemistry and spatial heterogeneity between the dam site (Daecheong Reservoir, S1) and the downstream (S2$\sim$S4) using water quality dataset (obtained from the Ministry of Environment, Korea) during 2000$\sim$2007. Water quality, based on eight physical and chemical parameters, varied largely depending on the years, sampling sites, and the discharge volume. Conductivity and nutrients (TN and TP) showed a decreasing trend in the downstream (S4) rather than the dam site during the monsoon. Spatial variation increased toward downstream (S4) from Daecheong Reservoir (S1). Also, BOD and COD increased toward downstream. Because of input of nutrient and pollutant nearby S1, lentic ecosystem in monsoon, BOD and COD were slightly increased. whereas relatively decreased in S4, lotic ecosystem in monsoon, by dilution effect of nutrient and pollutant by discharge from upper dam, S1. Spatial variation of SS increased toward downstream (S4) by the side of Daecheong Reservoir (S1). Based on the dataset, efficient water quality management in the point source tributary streams is required for better water quality of downstream. Monthly characteristics of DO showed the lowest value in the monsoon that tend to increase water temperature. DO was lowest in October at S1 because turbid water, input to the Daecheong Reservoir in the monsoon affect to the postmonsoon period. In contrast, water temperature increased toward summer monsoon, in spite of some differences showed between S1 and S4 environment. Overall, the characteristics of water quality in downstream region have close correlation with discharge amount of Daecheong Reservoir. Thus, those characteristics can explain that discharge control of upper dam mainly affect to the water quality variation in downstream reach.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.18 no.6
• /
• pp.511-518
• /
• 1985

As one of the sensory factors for characterizing food quality, volatile compounds have been particularly contributed to sensory evaluation of fermented sea foods in Korea. But no chemical investigation of the volatile compounds of fermented anchovy as one of the most favored fermented sea food products has been reported. Accordinglry, for a series study of processing of low salt fermented sea foods, changes in volatile compounds and fatty acid composition of fermented anchovy with low salt contents ($4\%$ of salt contents) were experimented fermentation comparing with conventional fermented anchovy ($20\%$ of salt contents). Total lipid of raw anchovy was composed of $77.6\%$ of neutral lipid, $22.1\%$ of phospholipid and $0.3\%$ of glycolipid. And polyenoic acid was held $39.8\%$ of fatty acid composition of total lipid and the major fatty acids in those were $C_{22:6},\;C_{20:5}$. During the fermentation of anchovy saturated fatty acid ($C_{16:0},\;C_{18:0},\;C_{l4:0}$) and monoenoic acid ($C_{16:1},\;C_{18:1}$) increased while polyenoic acid ($C_{22:6},\;C_{20:5}$) decreased greatly. Thirty-eight kinds of volatile component from the whole volatile compounds obtained from fermented anchovy after 90 days fermentation were identified, and composed of some alcohols (8 kinds), carbonyl compounds (9 kinds), hydrocarbons (8 kinds) and fatty acids (8 kinds). During fermentation 8 kinds of volatile acids, 5 kinds of amines, 9 kinds of carbonyl compounds were also detected. Those volatile acids such as acetic acid, isovaleric acid, propionic acid, n-butyric acid were the major portion of total volatile fatty acids of 60 days fermented anchovy prepared with low salt contents. On the other hand, carbonyl compounds such as ethanal, 3-methyl butanal, hexanal, 2-methyl propanal were the major ones, while TMA held the most part of volatile amines in fermented anchovy with low salt contents after 60 days. Conclusively, there was little difference in composition of volatile components, but merely a little difference in content of those between low salt fermented anchovy and conventional fermented ones.

• Parasites, Hosts and Diseases
• /
• v.27 no.3
• /
• pp.177-186
• /
• 1989

Observations were made on the differences in cell-mediated immune responses in the mice infected with strongly pathogenic Naegleria fewleyi ITMAP 359, weakly pathogenic Naegzeria jadini 0400, or non.pathogenic Naegleria gruberi EGB, respectively. Variations in cell-mediated responses and changes in antibody titers according to the duration after infection wore noted. Infections were done by dropping $5{\;}{\mu}l$ saline suspension containing $10{\times}10^4$ trophozoites cultured Bxenically in the CGVS medium into the right nasal cavity of ICR mice aging about 6~7 weeks, under the anesthesia by intraperitoneal injection of'secobarbital. Following infection, delayed type hypersensitivity(DTH) iesponses in the footpad and blastogenic responses of the mouse spleen cells using [$^3H$]-thymidine were observed on the day 1, 4, 7, 10 and 14 after infection. For the preparation of amoeba Iysates, each of cultured trophosoites were homogenized with an ultrasonicator, and centrifugated at 20,000 g. The supernatants of amoeba Iysates were used as the mitogen'and antigen for ELISA. Confanavalin A(Con. A) and lipopolysaccharide(LPS) were also used as mitogens in the blastogenic response. 1. The mice infected with N, fowleri showed the mortality rate of 75.7%. The rate was 6.2% for the N. jadini infected group, while no dead mouse was observed for N. gruberi infections. 2. In regard to DTH responses in the H. fewleri infected mice, the level increased in com- parison to the control group but declined after 7 days. An increase was also noted for the JV. jadini group after 1 day, but gradual decreases were observed through the infection period. In addition, no difference was noted between the N. gruberi infected and control groups. 3. Concerning the blastogenic response of the splenocytes, it increased after 10 days in the experimental group of N, fcwleri infection, but the differences ware not statistically significant compared with control group. It was evident that N. jadini group was not different from control group either, while there was a tendency of decrease in SV. gruberi infected group. In regard to the blastogenic response of the splenocytes by LPS, it was found that the N. fowlgri, N. jadini and N. gruberi infected groups had no differences from the control group. 4. The serum antibody titer of N. fcwleri and N. jadini infected mice increased from the day 7 and 14 after infection respectively, while the N. gruberi infected mice showed no increase. In summary of the results, it was observed that there were differences in the cell-mediated immune responses and serum antibody titers in the mice infected with strongly pathogenic JV. fowleri, weakly pathogenic N. jadini, or non.pathogenic N. gruberi, respectively.