• Resources Recycling
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• v.9 no.4
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• pp.16-27
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• 2000

In order to produce raw material powder of advanced magnetic material by spray roasting process, newly modified spray roasting system was developed in this work. In this spray roasting system, raw material solution was effectively atomized and sprayed into the reaction furnace. Also, uniform temperature distribution inside reaction furnace made thermal decomposition process fully completed, and produced powder was effectively collected in cyclone and bag filter. This system equipped with apparatus which can purify hazard produced gas. In this study complex acid solution was prepared by dissolution of mill scale and ferro-Mn into the acid solution, and the pH of this complex acid solution was controlled about to 4. It was conformed that mill scale and ferro-Mn containing a lot of impurities such as $SiO_2$, P and Al could be used as raw material by reducing the impurities content of complex acid solution below 20 ppm. Complex oxide powder of Fe-Mn system was produced by spraying purified complex acid solution into the spray roaster through nozzle, and the variations of produced powder characters were studied by changing he reaction conditions such as reaction temperature, the injection velocity of solution and air, nozzle tip size and concentration of solution. The morphology of produced powder had spherical shape under the most experimental conditions, and concentration of solution. The morphology of produced powder has spherical shape under the most experimental conditions, and the composition and the particle size distribution were almost uniform, which tells the excellence of this spray roasting system. The grain size of most produced powder was below 100 nm. From the above results, it will be possible to produce ultra fine oxide powder from the chloride of Fe, Mn, Ni, Cu and rare earth by using this spray roasting system, and also to produce ultra fine pure metal powder by changing reaction atmosphere.

• Korean Journal of Remote Sensing
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• v.14 no.1
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• pp.53-68
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• 1998

Observation of hydrometeors' behavior in the atmosphere is important to understand weather and climate. By conventional observations, we can get the distribution of water vapor at limited number of points on the earth. In this study, the precipitable water has been estimated from the split window channel data on GMS-5 based upon the technique developed by Chesters et al.(1983). To retrieve the precipitable water, water vapor absorption parameter depending on filter function of sensor has been derived using the regression analysis between the split window channel data and the radiosonde data observed at Osan, Pohang, Kwangiu and Cheju staions for 4 months. The air temperature of 700 hPa from the Global Spectral Model of Korea Meteorological Administration (GSM/KMA) has been used as mean air temperature for single layer radiation model. The retrieved precipitable water for the period from August 1996 through December 1996 are compared to radiosonde data. It is shown that the root mean square differences between radiosonde observations and the GMS-5 retrievals range from 0.65 g/$cm^2$ to 1.09 g/$cm^2$ with correlation coefficient of 0.46 on hourly basis. The monthly distribution of precipitable water from GMS-5 shows almost good representation in large scale. Precipitable water is produced 4 times a day at Korea Meteorological Administration in the form of grid point data with 0.5 degree lat./lon. resolution. The data can be used in the objective analysis for numerical weather prediction and to increase the accuracy of humidity analysis especially under clear sky condition. And also, the data is a useful complement to existing data set for climatological research. But it is necessary to get higher correlation between radiosonde observations and the GMS-5 retrievals for operational applications.

• Atmosphere
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• v.31 no.2
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• pp.229-240
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• 2021

The Global Ocean Data Assimilation and Prediction System (GODAPS) in operation at the KMA (Korea Meteorological Administration) is introduced. GODAPS consists of ocean model, ice model, and 3-d variational ocean data assimilation system. GODAPS assimilates conventional and satellite observations for sea surface temperature and height, observations of sea-ice concentration, as well as temperature and salinity profiles for the ocean using a 24-hour data assimilation window. It finally produces ocean analysis fields with a resolution of 0.25 ORCA (tripolar) grid and 75-layer in depth. This analysis is used for providing a boundary condition for the atmospheric model of the KMA Global Seasonal Forecasting System version 5 (GloSea5) in addition to monitoring on the global ocean and ice. For the purpose of evaluating the quality of ocean analysis produced by GODAPS, a one-year data assimilation experiment was performed. Assimilation of global observing system in GODAPS results in producing improved analysis and forecast fields with reduced error in terms of RMSE of innovation and analysis increment. In addition, comparison with an unassimilated experiment shows a mostly positive impact, especially over the region with large oceanic variability.

• Atmosphere
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• v.32 no.2
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• pp.87-101
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• 2022

In this paper, the performance improvement for the new KMA's Climate Prediction System (GloSea6), which has been built and tested in 2021, is presented by assessing the bias distribution of basic variables from 24 years of GloSea6 hindcasts. Along with the upgrade from GloSea5 to GloSea6, the performance of GloSea6 can be regarded as notable in many respects: improvements in (i) negative bias of geopotential height over the tropical and mid-latitude troposphere and over polar stratosphere in boreal summer; (ii) cold bias of tropospheric temperature; (iii) underestimation of mid-latitude jets; (iv) dry bias in the lower troposphere; (v) cold tongue bias in the equatorial SST and the warm bias of Southern Ocean, suggesting the potential of improvements to the major climate variability in GloSea6. The warm surface temperature in the northern hemisphere continent in summer is eliminated by using CDF-matched soil-moisture initials. However, the cold bias in high latitude snow-covered area in winter still needs to be improved in the future. The intensification of the westerly winds of the summer Asian monsoon and the weakening of the northwest Pacific high, which are considered to be major errors in the GloSea system, had not been significantly improved. However, both the use of increased number of ensembles and the initial conditions at the closest initial dates reveals possibility to improve these biases. It is also noted that the effect of ensemble expansion mainly contributes to the improvement of annual variability over high latitudes and polar regions.

• Korean Journal of Environment and Ecology
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• v.12 no.1
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• pp.58-77
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• 1998

Four species(25%) of Viperidae(Agkistrodon brevicaudus, Agkistrodon ussuriensis, Agkistrodon saxatilis) and Cloubridae(Rhabdophis tigrenus tigrenus) were Korean poisonous snake. Copulation season of these species was from July to August. Reproduction mode of genus Agkistrodon species was ovoviviparous but Rhabdophis tigrinus tigrinus was the other pattern of oviparous. Optimal movement temperature range was from 20$\circ $C to 29$\circ $C(March~September). Wjen atmosphere temperature was below 10$\circ $C, at that time they hibernate at the ground, rock bottom, stone wall and embankment around the end of a field. The venom of these snakes consist mainly Hematoxin, Cytolysin, Neurotoxin and Cardiotoxin of poisonous liquids. These material injection to animal cause systemic syndrome such as Dizziness(25.7%), Vomitting(23.1%), Fever(22%), Visual trouble(18%), Headace(17.7%), Dyspnoea(17.6%) and bring about other local syndrome such as Discoloration(54.2%), Bleeding(20.2%), Bullae(10.7%) and Skin ulcer(!0.8%). The annual distribution was appeared to decrease 1972 after 1992 and average snakebiting patients was 25.6 per year, but practically total estimated snakebiting was 2,700 per year. The seasonal distribution was most frequent in August(25%), and mortality was 1.8%(26 per 1,430). The sex ratio was 2:1 and according to age distribution, it was most prevalent at one's fifties(19%). The most frequent place where the accident happened was the field(48.2%) and most predilection site of the body for victim were hand(47.8%) and foot(39.5%), Commonly bite snake were Agkistrodon ussuriensis(27.1%), Agkistrodon brevicaudus(22.6%) and Agkistrodon saxatilis(9.6%) but 40.7% of species could not be identified. Treatment of antivenin patient was 75.9% (1,068/1,407).

• Journal of the Korean Geotechnical Society
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• v.39 no.5
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• pp.51-63
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• 2023

Numerical analysis was conducted to determine the effect of soil behavior by thawing and freezing of seasonal frozen soil on pile foundations. The analysis was performed using the finite element method (FEM) to simulate soil-pile interaction based on the atmosphere temperature change. Thermomechanical coupled modeling using FEM was applied with the temperature-dependent nonlinear properties of the frozen soil. The analysis model cases were applied to the MCR and HDP models to simulate the elastoplastic behavior of soil. The numerical analysis results were analyzed and compared with various conditions having different length and width sizes of the pile. The results of the numerical analysis showed t hat t he HDP model was relat ively passive, and t he aspect and magnit ude of t he bearing capacit y and displacement of the pile head were similar depending on the length and width of the pile conditions. The vertical displacement of the pile head by thawing and freezing of the ground showed a large variation in displacement for shorter length conditions. In the MCR model, the vertical displacement appeared in the maximum thaw settlement and frost heaving of 0.0387 and 0.0277 m, respectively. In the HDP model, the vertical displacement appeared in the maximum thaw settlement and frost heaving of 0.0367 and 0.0264 m, respectively. The results of the pile bearing capacity for the two elastoplastic models showed a larger difference in the width condition than the length condition of the pile, with a maximum of about 14.7% for the width L condition, a maximum of about 5.4% for M condition, and a maximum of about 5.3% for S condition. The significance of the effect on the displacement of the pile head and the bearing capacity depended on the pile-soil contact area, and the difference depended on the presence or absence of an active layer in the soil and its thickness.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.3
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• pp.274-282
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• 1984

In order to study the effect of seed-fertilizer vertical distance with soil moisture and fertilizer levels on the emergence and initial growth, barley cv. Olbori was seeded in the pots filled with sandy loam or loamy sand soils which were adjusted to 80-100% (higher soil moisture) or 50-60% (lower soil moisture) of soil moisture retention percent at 1/10 atmosphere tension. Prior to seeding of barley seed-fertilizer distance was appropriately controlled by adding soils after dressing fertilizer at three levels-normal application ($N:P_2O_5:K_2O=6-9-7kg/10a$), 50% increase of normal dose and double application. In addition, germination experiment was conducted in the various concentrations of fertilizer solutions under room temperature. The results are summarized as follows; 1. Seed-fertilizer vertical distance must be more than three centimeters to avoid from the decrease and retardation of emergence and poor initial growth of bareley by fertilizer application. 2. Emergence of barley more decreased and retarded in sandy soils than loamy soils and was decelerated with increase of application rate in fertilizer and decrease of soil moisture content. 3. Germination rate remarkably decrease from 0.4 percent of nitrogen solution and 0.5 percent of potassium solution and reached zero at 2.3 and 2.4 percent of nitrogen and potassium solutions, respectively. 4. Germination of seeds affected by concentrated fertilizer solutions was remarkably recovered with dilution degree of fertilizer solution.

• Journal of Animal Science and Technology
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• v.46 no.3
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• pp.459-468
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• 2004

An experiment was conducted to establish comparison of ventulation efficiency in an enclosed and conventional growing-finishing pig house. The main results of the experiment are as follows : In the established temperature was sustained at the level of summer 24.8${\sim}$29.1$^{\circ}C$, winter 17.9${\sim}$23.1$^{\circ}C$ during the experimental period of enclosed growing-finishing pig house, and conventional growing-finishing pig house was at the lovel of summer 24.7${\sim}$32.3$^{\circ}C$, winter 14.5${\sim}$18.2$^{\circ}C$ during the experimental period respectively. As for the results of dertimental gas(ammonia) concentration ratio analysis, while the conventional pig house sustained of summer 9.3${\sim}$16.9 mg/$\ell$ level, enclosed growing-finishing pig house sustained of summer 7.9${\sim}$16.1 mg/$\ell$, and the latter one is lower than that of the conventional growing-finishing pig house. Air flow rate on the floor level which is the low part of pen and the active area of pigs in the enclosed growing and finishing pig house during winter was measured at 0 to 0.87 m/s at the 0.01 to 2.73 m/s at the maximum ventilation efficiency. As for breeding pigs in summer, the pigs from the conventional pig house weighed 100.2kg, on the other hand, the pigs from enclosed growing-finishing pig house weighed 107.3 kg ; the differnce between the two kinds was about 7 kg. This was because the most adequate environment, which was not influenced by the exterior atmosphere, was offered to the pigs from enclosed growing-finishing pig house, and all of this could reduce pigs stress effectively.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.57-64
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• 1997

The research was investigated to determine the effect of organic acids or packaging methods (PA) either alone or in combination on the quality of Aster scaber during storages. The Aster scaber was treated with organic acids and PA, and stored at different temperature $(1\;and\;5^{\circ}C)$. Total plate counts, weight loss, color change, and sensory evaluation were evaluated. Both organic acid treatments, PA, and combined treatment had little effect on the inhibition of total plate counts compared to the control (non-treatment). Organic acid treatments showed less weight reduction compared to the control and nitrogen treated package had the least weight reduction, but the combined treatments showed less weight reduction than organic acid treatments or packaging method alone. Organic acid treatments were little different from the control on color change, but nitrogen packages had the least color change, whereas combined treatments were a little reduced, but little different compared to the control or nitrogen packages. The nitrogen packages showed better effects on the sensory evaluation compared to other treatments and the results of sensory evaluation were consistent with that of weight reduction and color change, but not in total counts. All these results showed better effects in $5^{\circ}C$ rather than $1^{\circ}C$.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.67-72
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• 2006

Injection of $CO_2$ into underground saline formations, due to their large storage capacity, is probably the most promising approach for the reduction of $CO_2$ emissions into the atmosphere. $CO_2$ storage must be carefully planned and monitored to ensure that the $CO_2$ is safely retained in the formation for periods of at least thousands of years. Seismic methods, particularly for offshore reservoirs, are the primary tool for monitoring the injection process and distribution of $CO_2$ in the reservoir over time provided that reservoir properties are favourable. Seismic methods are equally essential for the characterisation of a potential trap, determining the reservoir properties, and estimating its capacity. Hence, an assessment of the change in seismic response to $CO_2$ storage needs to be carried out at a very early stage. This must be revisited at later stages, to assess potential changes in seismic response arising from changes in fluid properties or mineral composition that may arise from chemical interactions between the host rock and the $CO_2$. Thus, carefully structured modelling of the seismic response changes caused by injection of $CO_2$ into a reservoir over time helps in the design of a long-term monitoring program. For that purpose we have developed a Graphical User Interface (GUI) driven rock physics simulator, designed to model both short and long-term 4D seismic responses to injected $CO_2$. The application incorporates $CO_2$ phase changes, local pressure and temperature changes. chemical reactions and mineral precipitation. By incorporating anisotropic Gassmann equations into the simulator, the seismic response of faults and fractures reactivated by $CO_2$ can also be predicted. We show field examples (potential $CO_2$ sequestration sites offshore and onshore) where we have tested our rock physics simulator. 4D seismic responses are modelled to help design the monitoring program.