• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.2
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• pp.2949-2967
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• 1973

The purpose of this study is to find out and determine the minimum consumptive use of water for Korean cabbage and turmp, so that the minimum water requirement can be secured always for a stable cultivation of these vegetables regardless of weather conditions. The experiment was conducted in two periods; first one from May to July and second one from August to October, each experiment with two varieties of cabbage and two varieties of radish with 2 replicants and 15 treatments. The results found from the above are briefly as follows: 1. Since the mean soil moisture equivalent 64 days after the treatment was 28.5% and the soil moisture content at the time was 2.67% which is far less than that of the wilting point, the crop seemed to be extremely caused by a drought. 2. The rate of 51 days after the seeding, soil moisture content of plot No.2 where irrigation has been continuous was the highest or 21.3%, whereas the plot No.14 without irrigations was 11.2% and the lowest. Therefore, the soil moisture content for the minimum qrowth seemed to be 20%. 3. The consumptive coefficient of Blaney and Criddle on cabbage in two periods were K=1.14 and 0.97 respectively, and on radish in two periods were K=1.06 and 0.86 respectively, thus, cabbage was higher than radish. The consumptive coefficient in the first experiment (May-July) was 0.17 to 0.20 higher than the 2nd experiment(August-October). 4. Nomally, cabbage and radish germinate within one week, however, the germination ot these crops which were treated with a suspended water supply from the beginning took two full weeks. 5. When it elapsed 30 days after seeding, the conditions in plot 1,2 and 3 were fairly good however, the crops in the plops other than these showed a withering and the leaves were withered and changed into high green due to an extrem drought. Though it was about same at the beginning, the drought damage on cabbage was worse than that on radish period, and the reasos for this appears in the latter that the roots are grown too deep. 6. The cabbage showed a high affinity between treated plots and varieties. Consequently, it can be said that cabbage is very suseptive to drought damage, and the yield showed a difference of 35% to 56% depending on the selection oe varieties. 7. The radish also showed a high affinity between the treated plots, however, almost us affinity existed between varieties. Therfore, the yield of radish largely depends on the extent of drought, and the selection of variety does not affect at all. 8. The normal consumptive use on cabbage is $0.62{\ell}/sec$, while that on radish is $0.64{\ell}/sec$, and the minimum optimum water requirement that was obtained in this study is $4,000cc/day/m^3$ or $0.462{\ell}/sec/ha$.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.460-466
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• 2009

Carbon fixation and density of crops are important to estimate carbon uptake or emission by agricultural production activities and to establish life cycle inventory of crops for assessment of climate change impact. In this study, regional carbon fixation and density in each part of 14 crops, harvest index, and ratio of aboveground to underground were investigated to estimate biomass of 14 crops in Korea by using agricultural statistics data. Biomass yield of potato was $16.5ton\;ha^{-1}$, which was the highest, and those of rice, sweet potato, and garlic were $10.5ton\;ha^{-1}$, $8.7ton\;ha^{-1}$, and $7.5ton\;ha^{-1}$ respectively. Biomass yield of Green onion was the lowest as $2.8ton\;ha^{-1}$. Carbon density of 14 crops were in the order of potato ($6.4ton\;ha^{-1}$), rice ($4.2ton\;ha^{-1}$), sweet potato ($3.4ton\;ha^{-1}$), rape ($2.9ton\;ha^{-1}$) and garlic ($2.8ton\;ha^{-1}$). Regional distribution of carbon contents for each crop mapped revealed that carbon fixation of rice, soybean, sesame, garlic, and green onion were the highest in Jeonnam province, barley, red pepper, and watermelon in Gyeongnam, perilla in Chungnam, peanut in Gyeongbuk, rape and carrot in Jeju, sweet potato in Gyeonggi, potato in Gangwon. The results can be applied for assessing life cycle inventory of crops and crop productivity using remotely sensed data.

• Asian Journal of Turfgrass Science
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• v.22 no.1
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• pp.65-74
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• 2008

Traffic management is becoming an important issue in turfgrass practise on golf course. The objective of this study was to investigate the combined impact of different traffic times and types of fertilization. Traffic treatment was applied in morning (AM), noon, and afternoon (PM). Fertilizers used include faster-release fertilizer (21-17-17) and slow-release fertilizers (12-6-18, 11-3-22, 20-3-20, 10-3-10). Experiment was conducted from Oct. 1 to Nov. 30, 2005 on a nursery putting green of Incheon Grand Golf Club. The growth and quality of creeping bentgrass (Agrostis polustris cv. 'Seaside II') were evaluated on visual leaf color, leaf texture, shoot density, and root length. The measurement at 20 days after treatment, turfgrass color and leaf texture showed the best result on 10-15-10 + Noon-traffic plot. Turf quality and traffic tolerance were not different at Am and Pm traffic treatment. However, traffic stress in early morning and late evening caused the most severe damage to the turfgrass. Shoot density was the highest in 10-15-10 + Noon-traffic treatment but root length was not different among treatments after 30 day measurement. Among the fertilizers, slow release fertilizer resulted in higher turf quality and traffic tolerance than fast release fertilizer, however, shoot density did not showed a significantly different. For the fast recuperation of turfgrass from traffic injury in the early winter, it is recommended to avoid early morning and late evening traffic such as cup replacement and other maintenance practise. It is also recommended to delay the first tee-up time and ending early for last tee time during cold weather season.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.4
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• pp.185-194
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• 2006

A fungal strain of Trichoderma having strong chitinolytic activity was isolated from field soil enriched with crabshell for several years. Based on 5.8S rRNA, partial 18S, 28S rRNA genes, ITS1, ITS2 sequence analysis and morphological characteristics, the fungus was identified as Trichoderma asperellum and named as Trichoderma asperellum T-5 (TaT-5). The fungus released lytic enzymes such as chitinase and ${\beta}$-1, 3-glucanse, and produced six antifungal substances in chitin broth medium. To demonstrate the protective effect of TaT-5 against damping-off in cucumber plant caused by Rhizoctonia solani, TaT-5 culture broth (TA), chitin medium (CM) and distilled water (DW) were applied to each pot at 10 days after sowing, respectively. Then, the homogenized hyphae of R. solani were infected to each pot at 1 week after TaT-5 inoculation. During experimental period, fresh weight of shoot and root in cucumber plant more increased at TA treatment compared to other treatments. PR-proteins (${\beta}$-1, 3-glucanase and chitinase) activities in cucumber leaves markedly increased at CM and DW treatments, but the activity slightly increased and then decreased at TA treatment at 3 days after infection of R. solani. The activity of PR-proteins activities in cucumber roots at all treatments decreased with time where the degree of decrement was more alleviated at TA treatment than CM and DW. These results suggest that the lytic enzymes (chitinase and ${\beta}$-1, 3-glucanse) and antifungal substances produced by TaT-5 can reduce the pathogenic attack by R. solani in cucumber plants.

• Investigative Magnetic Resonance Imaging
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• v.3 no.2
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• pp.173-178
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• 1999

Purpose : To evaluate the usefulness of functional MRI (fMRI) of visual cortex in patients with ischemic infarction in the occipital lobe. Materials and Methods : Four patients with the symptoms and signs of visual cortical ischemia were included. Functional MRI was performed by 2D-FLASH technique with the parameter of 90/56msec TR/TE, $40^{\circ}$ flip angle, $240{\times}240{\;}FOV,{\;}64{\times}128$ matrix number, 8.32 seconds acquisition time, 8mm slice thickness. An axial slice including both visual cortices was selected and alternative activation and resting of the visual cortex was performed using red color photostimulator. all patients undertook visual field test, and vascular abnormality was examined by MRA (n=4) and DSA (n=2). fMRI results were compared with the results of a visual field test, conventional MRI and cerebral angiography. Results : On fMRI, decreased activity of the visual cortex was found in the occipital lobe corresponding to stenosis of the posterior cerebral artery or its branch noted on angiogram. However, 2 of 4 patients showed no abnormal findings on conventional MRI. Visual field defect was noted in 3 patients, one and of whom showed no abnormality on conventional MRI and diffusion-weighted image, but revealed decreased activity in the corresponding visual cortex on fMRI. Conclusion : fMRI may be a sensitive method for detection of the status of decreased blood flow or vascular reserve which other methods can not.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.477-491
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• 2013

Natural radionuclides in groundwater in the Danyang area were investigated to characterize the behaviors of uranium and radon with respect to lithology and physico-chemical components, which can aid our understanding of their occurrence, properties, and origins. To this end, a total of 100 groundwater samples were collected and analyzed, and radionuclide levels were used to construct detailed concentration maps. The water type of the groundwater, assessed using a Piper diagram, is mainly Ca-Na-$HCO_3$. The concentrations of uranium range from 0.02 to $251.0{\mu}g/L$ (average, $3.85{\mu}g/L$) and only 1% exceed USEPA's MCL (Maximum Contaminant Level). Uranium is enriched in groundwaters of Cretaceous granites and Precambrian metamorphic rocks, whereas it is depleted in groundwaters of sedimentary rocks. The concentrations of radon range from 13 to 28,470 pCi/L (average, 2397 pCi/L). Only 15% of the samples exceed AMCL (Alternative Maximum Contaminant Level) of 4000 pCi/L. The radon concentration is highest in groundwater of Cretaceous granites and lowest in groundwater of sedimentary rocks. In conclusion, the distribution and occurrence of radionuclides are intimately related to the basic geological characteristics of the rocks in which the radiogenic minerals are primarily contained. The behavior of uranium is only weakly related to that of radon (correlation coefficient = 0.15). There are also weak correlations between radionuclides and the main chemical components, pH, EC, Eh, and well depth. Of note, the correlation coefficient between radon and $SiO_2$ is 0.68, and that between radon and $HCO_3$ is -0.48. Factor analysis shows that radionuclides behave somewhat independently of each other because there are no significant factors that control the behavior of chemical components as well as radionuclides. The detailed concentration maps during this study will be used to establish useful database of radionuclide distribution and geological properties throughout Korea.

• Economic and Environmental Geology
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• v.44 no.2
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• pp.123-133
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• 2011

The lab scale experiments to investigate the geochemical reaction among supercritical $CO_2$-mineral-brine which occurs at $CO_2$ sequestration sites were performed. High pressurized cell system (l00 bar and $50^{\circ}C$) was designed to create supercritical $CO_2$ in the cell, simulating the sub-surface $CO_2$ storage site. From the high pressurized cell experiment, the surface changes of Ca-feldspar, amphibole (tremolite) and olivine, resulted from the supercritical $CO_2$-mineral-brine reaction, were observed and the dissolution of minerals into the brine was also investigated. The mineral slabs were polished and three locations on the surface were randomly selected for the image analysis of SPM and the surface roughness value (SRV) of those locations were calculated to quantify the change of mineral surface for 30 days. At a certain time interval, SPM images and SRVs of the same mineral surface were acquired. The secondary minerals precipitated on the mineral surfaces were also analyzed on SEM/EDS after the experiment. From the experiments, the average SRV of Ca-feldspar increased from 2.77 nm to 20.87 nm for 30 days, suggesting that the dissolution of Ca-feldspar occurs in active when the feldspars contact with supercritical $CO_2$ and brine. For the amphibole, the average SRV increased from 2.54 nm to 8.31 nm and for the olivine from 0.77 nm to 11.03 run. For the Ca-feldspar, $Ca^{2+}$, $Na^+$, $Fe^{2+}$, $Si^{4+}$, $K^+$ and $Mg^{2+}$ were dissolved in the highest order and $Si^{4+}$, $Ca^{2+}$, $Fe^{2+}$ and $Mg^{2+}$ for the amphibole. Fe (or Mg) - oxides were precipitated as the secondary minerals on the surfaces of amphibole and olivine after 30 days reaction. Results suggested that $Ca^{2+}$, $Fe^{2+}$ and $Mg^{2+}$ rich minerals would be significantly weathered when it contacts with the supercritical $CO_2$ and brine at $CO_2$ sequestration sites.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.3
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• pp.188-194
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• 2007

The relationships between pine mushroom emergence and meteorological factors were analyzed with three years (from 2003 to 2005) of measurement data at Yangyang site, in order to evaluate the effect of micrometeorological environment on pine mushroom production. fine mushroom was daily monitored and collected in the survey area during the its producing period (approximately one month). Pine mushroom production was highest in 2005 with the meteorological conditions of high temperature and frequent rainfalls in October. The production was lowest in 2004 due to dry conditions from mid September to late October, The meterological factors related to humidity (i.e., relative humidity, soil water content, and precipitation) were better correlated than those related to temperature (i.e., air and soil temperature, soil heat flux and solar radiation) with pine mushroom production. However, all of the correlation coefficients were statistically insignificant with values ranging from 0.15 to 0.46. Such poor correlations may be attributed to various other environmental conditions (e.g., topography, soil, vegetation, other fungi, the relationship between pine mushroom and pine forest) affecting pine mushroom production. We found that a mycelium requires a stimulation of low temperature (of three-day moving average) below $19.5^{\circ}C$, in order to farm a mushroom primordium which grows to pine mushroom after 16 days from the stimulation. We also found that the pine mushroom production ended when the soil temperature (of three-day moving average) fell below $14.0^{\circ}C$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.3
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• pp.217-224
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• 2008

In deep geological disposal system, the integrity of a disposal canister having spent fuels is very important factor to assure the safety of the repository system. This disposal canister is one element of the engineered barriers to isolate and to delay the radioactivity release from human beings and the environment for a long time so that the toxicity does not affect the environment. The main requirement in designing the deep geological disposal system is to keep the buffer temperature below 100$^{\circ}C$ by the decay heat from the spent fuels in the canister in order to maintain the integrity of the buffer material. Also, the disposal canister can endure the hydraulic pressure in the depth of 500 m and the swelling pressure of the bentonite as a buffer. In this study, new concept of the disposal canister for the CANDU spent fuels which were considered to be disposed without any treatment was developed and the thermal stability and the structural integrity of the canister were analysed. The result of the thermal analysis showed that the temperature of the buffer was 88.9$^{\circ}C$ when 37 years have passed after emplacement of the canister and the spacings of the disposal tunnel and the deposition holes were 40 m and 3 m, respectively. In the case of structural analysis, the result showed that the safety factors of the normal and the extreme environment were 2.9 and 1.33, respectively. So, these results reveal that the canister meets the thermal and the structural requirements in the deep geological disposal system.

• Journal of Soil and Groundwater Environment
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• v.13 no.4
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• pp.30-39
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• 2008

The uranium removal efficiency of rhizofiltration was investigated in lab scale experiment. Three plants such as sunflower (Helianthus annuus L.), bean (Phaseolus vulgaris var.), and Indian mustard (Brassica juncea (L.) Czern.) were cultivated in artificially contaminated solution by uranium at 30 ${\mu}g$/L and 80 ${\mu}g$/L for 72 hours. The removal efficiencies of three cultivars were calculated from the ICP/MS analysis of uranium mass in solution and the plant. For Helianthus annuus L., more than 80% of initial uranium were removed from the solution and the uranium concentration of residual solution maintained lower than 10 ${\mu}g$/L. For Phaseolus vulgaris var. and Brassica juncea (L.) Czern., their uranium removal efficiencies ranged from 60 to 80%. Even the uranium concentration of solution was higher than 500 ${\mu}g$/L, these cultivars removed more than 70% of initial uranium by rhizofiltration, suggesting that the rhizofiltration has a great capability to remove uranium in the contaminated groundwater. The removal efficiency of rhizofiltration by using Brassica juncea (L.) Czern decreased from 83% to 42% with the increase of pH in solution. From the results of the analysis for the uranium accumulation in plants, 99% of uranium transferred into the plant from solution were accumulated in the root and only 1% of uranium existed in the shoot part (including leaves), suggesting that the cost and the time to treat massive grown plants after the rhizofiltration could be dramatically cut down because only their root parts needs to be treated. Finally, the genuine groundwater having high uranium concentration (81.4 ${\mu}g$/L), sampled from Daejoun area, was used in the experiment. The uranium removal efficiency of Helianthus annuus L. for the real groundwater was higher than 95%, investigating that the rhizofiltration is the very useful method to remediate uranium contaminated groundwater.