• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.418-427
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• 1997

The effect of $La_2O_3$ as a dopant on the microstructure structure, crystal structure and electrical properties was studied. $0.05Pb(Sn_{0.5}Sb_{0.5})O_3＋0.11PbTiO_3＋0.84PbZroO_3＋0.4Wt%MnO_2$ (=0.05PSS ＋0.11PT＋0.84PZ+0.4wt%$MnO_2$) systems doped with 0, 0.1, 0.3, 0.5, 0.7, 1, 3, 5 mole% $La_2O_3$ were fabricated and investigated sintering density, crystal structure and micro-structure. The sintered 0.05PSS＋0.11PT＋0.84PZ+0.4wt%$MnO_2$ system doped with $La_2O_3$showed sintering density of the range of 7.683 g/㎤ of 0 mole% doping to 7.815 g/㎤ of 0 mole% doping. The average grain sizes in the range of 0 to 5 mole% $La_2O_3$were decreased from 9.0 $\mu\textrm{m}$ to 1.3 $\mu\textrm{m}$. X-ray diffraction investigation of sintered bodies showed that solid solutions were formed between 0.05PSS＋0.11PT＋0.84PZ+0.4wt%$MnO_2$ system and $La_2O_3$ in the range of 0 to 1 mole% but second phases were formed in case of 3, 5 mole%. Dielectric constants at 1 kHz were increased with 0 to 3 mlole% $La_2O_3$ before and after poling at the condition of 5 $KV_{DC}$/mm at $120^{\circ}C$ or $140^{\circ}C$ during 20 minutes. All Dielectric losses at 1 kHz were less than 1%, Curie temperatures were $208^{\circ}C$, $183^{\circ}C$, $152^{\circ}C$ and $127^{\circ}C$ at 0, 0.5, 1, 3 mole% $La_2O_3$ respectively. The values of $K_p$ were increased from 0 to 3 mole% $La_2O_3$ after poling at condition of 5 $KV_{DC}$mm at the condition of $120^{\circ}C$ or $140^{\circ}C$. The case of 0.7 mole% $La_2O_3$doped 0.05PSS＋0.11PT＋0.84PZ+0.4wt%$MnO_2$ system showed $K_p$ of 14.5% by poling at $140^{\circ}C$ during 20 minutes.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.3
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• pp.181-188
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• 2007

Objective of this research was to identify by-product composting impacts on paddy soil properties and rice yield. Research was conducted in Iksan (soil was identified as a Jeonbug series) located in Honam plain area from 2001 to 2004. Composts, such as cow manure sawdust compost(CMSC), Chicken manure sawdust compost(ChMSC) and Pig manure sawdust compost(PMSC) were treated in the reseach plots for every, 2, and 3 year term. Some physical properties, such as, soil hardness, and bulk density tended to decrease with application of compost and decreased in order of CMSC, ChMSC, and PMSC, while surface soil depth and porosity were increased in order of CMSC, PMSC, and ChMSC. Some chemical soil properties, such as organic matter, available phosphorus, available silicate, and exchangeable cations were increased with application of compost and every year application plots. Nitrogen uptake was higher in order of CMSC, ChMSC, SF, and PMSC. Nitrogen use efficiency was higher in order of CMSC, ChMSC, SF, and PMSC. Rice yields was increased in all application plot of CMSC, in every other year application plot ChMSC and PMSC compared with SF($5.07Mg\;ha^{-1}$). Also average rice yield on years were increased in all application plot of CMSC and in every other year application plot ChMSC, while decreased in all application plot of PMSC compared with SF($5.27Mg\;ha^{-1}$). Head rice ratio and perfect grain ratio on hulled rice was high in all application plot of PMSC and in every year, in every other year app lication plot of ChMSC while its lowered percentage of 10~13 caused by application of CMSC compared with SF.

• Ocean and Polar Research
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• v.42 no.3
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• pp.233-247
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• 2020

This study was carried out at 5 sites 11 times over two years to identify the variation of benthic environments and benthic polychaetous community and analyze the benthic healthiness in Dangdong Bay, a small semi-enclosed inner bay of Jinhae Bay. The temperature of bottom water showed the typical temporal fluctuation of a temperate zone and was in the range of 5.94 ~ 23.94℃. The salinity did not change significantly during the study period and was in the range of 32.93 ~ 35.72 psu. The concentration of dissolved oxygen of bottom water fluctuated a great deal and was in the range of 0.31 ~ 10.20 mg/L. The lowest DO value was recorded in July 2015, as 0.31±0.04 mg/L corresponding to the hypoxic water mass. The hypoxic water mass was formed continuously at some sites also in July and August 2016. The mean grain size was in the range of 7.57 ~ 9.81Ø and the average was 8.89±0.20Ø. The surface sediments were mainly composed of fine sediment (mud) above 85%. The mean of TOC was 3.09±0.22% and LOI was 13.30±0.47%, showing very high levels in Korean coastal waters. The concentration of AVS was in the range of 0.33 ~ 1.28 mgS/g-dry. The high values of organic contents and AVS indicated that there had been the serious organic enrichment in Dangdong Bay. The number of species and the density of the benthic polychaetous community in Dangdong Bay were in the range of 2 ~ 38 species and 2 ~ 2,185 ind./㎡ during the study period. The number of species and density were highly sustained in winter and spring, and then decreased gradually with the formation of a hypoxic water mass in summer, and the lowest number of species and density were recorded in autumn. In September and November 2015, the dead zone expanded to almost the whole study area. Dominant polychaetous species were Capitella capitata, Lumbrineris longifolia, Paraprionospio patiens and Sigambra tentaculata, each known as opportunistic species and potential organic pollutant indicator species. In particular, Paraprionospio patiens showed a very high population density of 2,019 ind./㎡ in December 2016. Polychaetous communities at each sampling time were classified into 4 temporal groups according to dominant species in each period by cluster analysis and nMDS. 'Period Group AI' was formed in winter and spring of 2015, dominated by Capitella capitata, 'Period AII' in summer dominated by Lumbrineris longifolia, 'Period B' in autumn with no fauna in the dead zone, and particularly 'Period C' in winter of 2016 dominated by Paraprionospio patiens. As a result of analysis of benthic healthiness, the study area was estimated to be in a Fair~Very Poor condition by AMBI and in a Poor~Very Poor condition by BPI during the study period. Both AMBI and BPI showed that the study area was in a Very Poor condition in September and November 2015, and when the dead zone occurred. In Dongdong Bay, the fact that the formation of a hypoxic water mass occurred in summer and a dead zone in autumn were confirmed. In addition, the dominance of opportunistic and organic pollutant indicator species was also observed clearly. The benthic healthiness indexes such as AMBI and BPI showed that organic enrichment was serious in Dangdong Bay.

• Korean Journal of Remote Sensing
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• v.33 no.5_2
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• pp.699-708
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• 2017

The present study was to develop an approach for predicting soybean yield using a crop growth simulation model at the regional level where the detailed and site-specific information on cultivation management practices is not easily accessible for model input. CROPGRO-Soybean model included in Decision Support System for Agrotechnology Transfer (DSSAT) was employed for this study, and Illinois which is a major soybean production region of USA was selected as a study region. As a first step to predict soybean yield of Illinois using CROPGRO-Soybean model, genetic coefficients representative for each soybean maturity group (MG I~VI) were estimated through sowing date experiments using domestic and foreign cultivars with diverse maturity in Seoul National University Farm ($37.27^{\circ}N$, $126.99^{\circ}E$) for two years. The model using the representative genetic coefficients simulated the developmental stages of cultivars within each maturity group fairly well. Soybean yields for the grids of $10km{\times}10km$ in Illinois state were simulated from 2,000 to 2,011 with weather data under 18 simulation conditions including the combinations of three maturity groups, three seeding dates and two irrigation regimes. Planting dates and maturity groups were assigned differently to the three sub-regions divided longitudinally. The yearly state yields that were estimated by averaging all the grid yields simulated under non-irrigated and fully-Irrigated conditions showed a big difference from the statistical yields and did not explain the annual trend of yield increase due to the improved cultivation technologies. Using the grain yield data of 9 agricultural districts in Illinois observed and estimated from the simulated grid yield under 18 simulation conditions, a multiple regression model was constructed to estimate soybean yield at agricultural district level. In this model a year variable was also added to reflect the yearly yield trend. This model explained the yearly and district yield variation fairly well with a determination coefficients of $R^2=0.61$ (n = 108). Yearly state yields which were calculated by weighting the model-estimated yearly average agricultural district yield by the cultivation area of each agricultural district showed very close correspondence ($R^2=0.80$) to the yearly statistical state yields. Furthermore, the model predicted state yield fairly well in 2012 in which data were not used for the model construction and severe yield reduction was recorded due to drought.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.1
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• pp.39-48
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• 1977

The results of the determination of the optimum level of nitrogen fertilizer experiment for rice paddy at 21 locations over the country in 1975 year are as follows. 1. The yields of control and N-fertilized plots of ordinary variety (Japonica type) were normal paddy soil>sandy paddy soil>poorly drained paddy soil. Control plots of Tongil variety, (Indica type) however, were sandy poorly drained soil>sandy normal paddy soil=clay poorly drained soil, and N-fertilized plots were normal paddy soil>sandy poorly drained soil>sandy soil>clay poorly drained soil. In other words Tongil variety has higher adaptability to sandy soil under no nitrogen. 2. The yield response to N-fertilizer was higher in normal paddy soil than sandy soil. The productivity per 1kg of nitrogen was 16.6kg in normal paddy soil, 10.5 in sandy soil, and 8.6-11.4 in poorly drained soil for Tongil variety. For ordinary variety, they were 12.6, 6.3, 6.6-9.3kg respectively. 3. Ripening ratio for ordinary variety and ripening ratio and grain weight for Togil variety were higher in sandy soil than normal paddy soil. The main reason why the N-response in mormal paddy soil is higher was appeared to be higher number of effective tillers in normal paddy soil. 4. The optimum rates of N-fertilizer in average were 19.4 in normal paddy soil, 14.6 in sandy soil, and 11.6-13.4kg/10a in poorly drained soil for Tongil variety. For ordinary variety they were 15.9, 10.2, and 8.7-12.7kg/10a respectively. 5. The optimum rate of nitrogen was increased with the increase of productivity in normal paddy soils. In sandy soils and poorly drained soils it was not proved. 6. The optimum rates of N-fertilizer calculated from field experiment were somewhat different from the optimum rates calculated from $SiO_2/OM$ ratio. However, the values calculated both ways showed high correlation. It would be recommendable, therefore, to use $SiO_2/OM$ ratio to calculate the optimum rates of N-fertilizer after revising this equation considering different rice varieties and soil types or water management and climate.

• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.51-56
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• 2007

The two species of rice bugs causing pecky rice, Cletus punctiger and Cletus schmidti are often observed coexisting in the rice fields of nearby fallow land. Direct feeding damage to rice by C. punctiger and C. schmidti can lead to a reduction in grain quality and quantity. These studies were carried out to investigate the development of C. punctiger and C. schmidti at various constant temperatures ranging from 20 to $30^{\circ}C$, 65% RH, and a photoperiod of 16L:8D. Egg hatchability of C. punctiger/C. schmidti at the temperatures of 20, 25 and $30^{\circ}C$ were 80.6/88.0, 91.7/96.3, 96.4/96.2%, respectively. The development periods of eggs of C. punctiger/C. schmidti at the temperatures of 20, 25, and $30^{\circ}C$ were 16.4/18.4, 9.4/10.2 and 6.4/7.3 days, respectively. Mean developmental periods of 1 st, 2nd, 3rd, 4th and 5th nymphs of C. punctiger/c. schmidti at $30^{\circ}C$ were 2.1/2.0, 3.5/4.0, 3.3/5.6, 3.2/4.8 and 5.8/6.9 days, respectively. Oviposition began 8.1 days after emergence at $25^{\circ}C$, and the longevity of female and male were 120.0 and 117.3 days, respectively. Total number of eggs through the life of female were 245.5 laying 2.2 eggs a day in average at $25^{\circ}C$. The development periods of egg and nymphs of C. punctiger were relatively shorter than those of C. schmidti. Availability of male had affected the egg hatchability greatly that laid at 30th day after 60 days period of oviposition in the presence of adult male of C. punctiger. The fertile eggs laid by the female together with male was 92.1% but those without male was only 9.6%.

• Journal of Nutrition and Health
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• v.6 no.1
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• pp.39-46
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• 1973

This study was projected to get basic data which can provide a basis for future direction in nutritional education, and also to find the way how to improve the nutritional supply by evaluating the current nutritional intake of average high school students through the survey study of their daily packed lunch. Five hundred twenty seven students from two boys high school and two girls high school including one general and one vocational school respectively were chosen as random sampling technique. Four hundred forty nine among the 527 students had brought lunch. The contents of lunch box were weighed and converted into nutritional values according to the food composition table and compared with recommended dietary allowances. The results compared and classified by sex, School and housewives' educational level were as follows: 1. The nutritional supply in the lunch box was 671 Cal of energy and 22.3 gm of protein for male students which were respectively 55.9% and 74.2% of the dietary recommendations. On the other side female student's lunch boxes were found to contain 495 Cal of energy and 21.3gm of protein which are respectively 61.8% and 80% of the dietary prescriptions. Excluding niacin, all vitamins and minerals were found to be short. 2. Calorie intake in the vocational high school was found to be higher than in the general high school but lower in protein intake especially significant difference (P<0.01) in animal protein. 3. From the nutritional point of view the educational backgrouud of the housewives was not found to have any influence in the way of preparing the lunch boxes. 4. Nutrients of lunch box were heavily inclined to grain rather than to side dishes.

• Applied Biological Chemistry
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• v.20 no.2
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• pp.247-254
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• 1977

Acrylamide gel electrophoretic pattern of 13 wild soybean (Glycine ussuriensis) was compared with that of G. gracilis and G. max var. Gwanggyo. Average Protein content (50%) of wild soybean was greater than that of C. gracilis (46%) and Gwanggyo (45%). Grain weight of wild soybean was one third of G. gracilis and one ninth of Gwanggyo. Electrophoresis of wild soybean protein showed total 16 different bands and three of which (Rm 0.09, 0.59 and 0.84) were specific and did not appeared in 86 var. of G. max which showed four specific bands (Rm 0.35, 0.45, 0.50 and 0.77) of total 17 bands. G. glacilis had all bands of Gwanggyo and two bands (Rm 0.53 and 0.59), one of which (Rm 0.59) was specific for wild soybean indicating that G. gracilis is middle type. Of 16 protein bands the third band (32%), the first band (28%) and the 5th band (13%) were main bands. Electrophoretic pattern could be sorted qualitatively into 4 groups, semiquantitatively into 6 groups and 2 or 4 groups depending on reference pattern by correlation or pattern similarity method. All sorting methods separated a wild soybean from Sogri mountain into a group and except that there were no similarity among methods but correlation methods seems more reasonable. Protein content was no relation with electrophoretic pattern but positively correlated with percent contribution of first band at 5% level suggesting that the first band may have a important role for protein synthesis.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.6
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• pp.570-581
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• 2013

To improve productivity of aquaculture animals with management of culturing grounds, survey of mariculture management area in Ongjin-gun about water quality and sedimentary environment had been conducted on June, August and November in 2011. Water temperature in surface and bottom waters ranged from 9.49 to $24.14^{\circ}C$. Salinity and dissolved oxygen concentrations were in the range of 23.19~31.49 and 5.48~9.36 mg/L, respectively, depending on the variation of water temperature. The average concentration of COD was 1.57 mg/L and the concentrations of DIN and DIP showed entirely low level. As the result of grain size analysis, sand(56.66 %) and silt(34.60 %) were predominated. The Mz of sediment showed a variation of 2.59 to $6.62{\O}$ and sorting appeared to be poorly sorted. The concentrations of COD and IL in surface sediment ranged from 1.00 to $11.03mg/g{\cdot}dry$ and 0.72 to 5.29 %, respectively, which showed relatively good positive correlations. On the environmental assessment of trace metals in surface sediment, geoaccumulation index ($I_{geo}$) class indicated that sediments were not contaminated by most of metallic elements except Cr and As. Our result implies that this study area showed good water quality and sediments were not polluted by organic matters and metallic elements.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.687-697
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• 2019

By monitoring sediment grain size and level variation of tidal flat surface for 6 years (2005-2011), and also by mooring TISDOS (tidal-flat sediment dynamics observation system) on the low intertidal flat in 2008, we investigated the sedimentary environment of tidal flat in the dammed Yeongsan River Estuary. The tidal flat of the Yeongsan River Estuary lost 82 % of its area because of coastal development projects, and a narrow tidal flat below mean sea level now remains. Most of the tidal flat sediments are composed of silt up to 70-94 %, and show the characteristics of clay deficiency and silt dominance. This is closely related with the coastal development, which led to the destruction of high tidal flats where most mud settled, and the modification of tidal current patterns. Moreover, the estuarine tidal-flat sediments reveal seasonal variation. They are coarse with abundant silt during windy autumn to spring, fine with abundant clay during the less-windy and high-discharge summer. This phenomenon indicates that the behavior of sediment particles on the low intertidal flats of the Yeongsan River Estuary is influenced by wind waves for silt and fresh water discharge and the tidal process for clay. Monitoring results of the altitude of tidal flat surface showed that the study area had eroded at an average rate of -2.6 cm/y during the period of 2005-2011, and also that an unusual deposition with a rate of 4 cm/y occurred in 2010. The erosion can be explained by an increased tidal amplitude and a strengthened ebb-dominant tidal asymmetry after the construction of an estuary dike and the Yeongam Kumho Seawall. The deposition in 2010 seems to have been closely related to the mass production of suspended materials from dredging of the estuary.