• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.1-10
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• 2000

An experimental study regarding the effect of emulsions on RO is presented. Heavy oil was added to the sea water and the distilled water separately and treated for 30 minutes by a homogenizer to make emulsions. For the case of the sea water without heavy oil the permeate decreased from the beginning of the experiment. Chloride and conductivity increased with time, due to the fouling occurring as the suspended solids in the sea water accumulated on the membrane surface. Rejection rate of salt was 99.6~99.7%. As for the sea water containing heavy oil, the permeate decreased slowly from the beginning of the experiment. This result was the same for the case of the sea water only. However. chloride and conductivity increased significantly when heavy oil was added. In the second experiment with sea water containing heavy oil, the operation time of RO was reduced considerably. With addition of oil, the chloride increased greatly, while the permeate reduced comparatively. In the experiment where emulsion of $0.3{\sim}0.8mg/{\ell}$ was supplied to RO. oil concentration was about 10ppb in the permeate at the end of the experiment. In case of the distilled water containing heavy oil. the conductivity increased. However. the permeate reduced to 30% compared to the case of the sea water containing heavy oil. The case of sea water containing heavy oil showed an opposite result, but the effect of the addition of oil on RO was significant. Oil caused fouling of the RO and the contamination of the whole system, and as the result the system could not be operated properly. As a result the membrane capacity, the amount and water quality of permeate deteriorated significantly.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.10-14
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• 2001

The cooling effect of a fog cooling system has a close relationship to air flow and relative humidity in the greenhouse. From the VETH chart for cooling design, a cooling efficiency can be improved by means of increasing the air exchange rate and the amount of sprayed water. In the no shading experimental greenhouse by time control, when average air exchange rate was 0.77 times.min$^{-1}$ and spray water amount was 2,009g, inside temperature of the greenhouse was 31$^{\circ}C$ that was almost close to outside temperature and cooling efficiency was 82%. When average air exchange rate was close to temperature of the greenhouse that was no cooling and 70% shading greenhouse environment. When average air exchange rate was 2.59times.min$^{-1}$ , spray water amount was 2,009g and shading rate was 70%, inside relative humidity of the greenhouse was increased was 2,009 g and shading rate was 70%, inside relative humidity of the greenhouse was increased, but temperature was not decreased. When average air exchange rate was 2.33 times.min$^{-1}$ and spray water amount was 2,009g, inside temperature was 31.4 and at that time maximum wind speed at the air inlet of greenhouse was 1.9m.s$^{-1}$ . Since time controller sprayed amount of constant water at a given interval, some of sprayed water remained not to be evaporated, which increased relative humidity and decreased cooling efficiency. Because the shading screen prevented air flow in the greenhouse, it also caused the evaporation efficiency to be decreased. In order to increase cooling efficiency, it was necessary to study on controling by relative humidity and air circulation in the greenhouse.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.4
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• pp.428-436
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• 1995

The studies were conducted to escape for laber concentration during rice harvest and barley sowing through the scattering sowing before rice harvest(SS) compared to the drilling on high ridge(DS) of barley from 1990 to 1994. There were longer in plant height and more in tiller number under the SS than those under the DS of barley while cold-injured leaves of barley were inversely affected by two different sowing methods. The barley growth was more vigorous in the DS. There was similar at heading and maturing date. The grain yield of barley was lower in the SS by 20.6% which was resulted from the reduction of spike number per m$^2$ and number of grain per spike. There was not significant at growth and yield for sowing date before rice harvest. The variation of successive years on growth, yield and its components were higher in the SS than those in the DS.

• Journal of Ginseng Research
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• v.28 no.4
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• pp.196-200
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• 2004

This study was conducted to compare the root weight, yield, quality of fresh and red ginseng roots and crude saponin content in roots between fixing light transmittance(Control) and changing light transmittance(C.L.T.) during the ginseng growing seasons. The root weight in C.L.T. was higher than control by $35{\%}$ in early growth stage, $28{\%}$ in middle growth stage and $26{\%}$ in late growth stage in 6 years old ginseng plant. Root yield per 10a in C.L.T. was increased about $40{\%}$ as compared with that of control, also 1st and 2nd grade of fresh ginseng roots in C.L.T. was higher $(50.3{\%})$ compared with that $(12.9{\%})$ of control. The specific gravity of ginseng roots grown under the C.L.T. was exhibited the sig­nificant difference than control during the growing season in 4 and 6 years old ginseng plants. Red ginseng quality in C.L.T. was not only improved remarkably due to the increasement of heaven and earth grade red ginseng but also increased in crude saponin content than control. Therefore it needs to change the light transmittance(increasing light dur­ing low temperature periods and decreasing light during high temperature period) during the growing season for high yield and good qualities of ginseng roots.

• Korean Journal of Medicinal Crop Science
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• v.5 no.2
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• pp.162-166
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• 1997

Variations in growth and yield of adlay(Coix lachyma-jobi var. ma-yuen Stapf) was monitored in farmer's fields in Yunchon, the main producing area in Korea, where the field condition showed difference in topograyphy, crop rotation, and ridge shape. Rotation cropping increased remankably stem length, and number of effective tillers, reduced the occurrence of leaf blight and crop damage by the disease, and in addition showed positive effect to repress the occurrence of stem-borerin upland field. Stem length was greater in upland field than in paddy field and this result seemed to be related to lodging degree. The even field with crop rotation system showed the highest seed yield and followed by hillside field and paddy field resulted the lowest yield.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.338-338
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• 2018

최근들어 지속적인 연강수량의 부족으로 인해 댐 유역의 저류량이 감소하여 해마다 용수부족에 대한 위험성이 높아지고 있다. 댐으로 유입하는 유량은 댐 상류유역의 강우에 의해 발생되는 직접유출과 간접유출에 의해 저류되지만 실제 댐 유량에 크게 기여하는 부분은 유효강우량이상으로 많은 비가 오는 집중호우나 태풍등에 의한 강우로 인해 댐으로 유입되는 유량이다. 그러나 비가오는 기간은 점차 줄어들고 강우의 돌발성은 더욱 증가되고 있어 실제 무강우기간이 길어짐에 따라 토양으로 침투되는 양은 많아지고 댐으로 유입되는 유량의 변화는 과거에 비해 커질 수 있는 현실이다. 본 연구에서는 안동댐 유역의 강우관측소에서 발생한 홍수사상에 대한 유역평균강우를 산정하고 안동댐으로 유입되는 유량을 검토하여 강우와-유출고를 비교검토하여 무강우일수와 유출고와의 관계를 검토하고자 한다.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.3
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• pp.156-164
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• 2004

This study was conducted to evaluate the effect of the application of green manure in the form of either green barley and Chinese milkvetch in reducing the amounts of N fertilizers and conventional fertilizers needed for paddy rice. Prior to rice transplanting, the green barley and Chinese milkvetch as a green manure produced respectively $668kg\;10a^{-1}$ and 3,492kg\;$10a^{-1}$ in fresh shoot weight basis. Calculated nitrogen content from harvested green manures was 3.9 and $17.8kg\;10a^{-1}$, respectively. Plant height and tiller number of rice increased when two kinds of green manure incorporated into soil. Above mentioned parameters also increased with increasing amounts of N fertilizers at both ear formation and heading stage of rice. Rice grain number was not affected by green manures treatment but increased when N fertilizers were applied. Although rice panicle and grain number increased with green manure treatments and fertilizer applications, whereas the percentage of ripened grain decreased. Chinese milkvetch with additional N fertilizer applications increased brown rice yield from 1 to 5% compared to rice yields in plots where non-green manure with the conventional amount of fertilizer application was applied. Rice treated with Chinese milkvetch and 30% of the conventional N fertilizer rate yielded the same as rice fertilized conventionally. During the rice growing season, $NH_4-N$ content of paddy soil was higher in green manures treatment than non-green manure one. Average $NH_4-N$ content in paddy soil drastically decreased after heading stage below $5.7mg\;kg^{-1}$ in non-green manure treated plots. While on the other, $NH_4-N$ content in soil slowly decreased in plots those were treated with green manures at harvesting stage, average $NH_4-N$ content was still greater than $5.5mg\;kg^{-1}$. Nitrogen content of rice shoot and brown rice seed was higher in green manure treatment.

• Korean Journal of Medicinal Crop Science
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• v.7 no.2
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• pp.121-128
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• 1999

This experiment was carried out to establish effective weed control system in the cultivation of Coix lachryma-jobi L. The effect of annual weeds artificially transplanted on the growth of Coix lachryma-jobi L. were that the higher the density of weeds, the lower the yield considerably by reducing number of grains and tillers per plant. Among four weeds of Echinochloa crusgalli galli P. BEAUV., Digitaria sanguinalis $S_{COPOL}$., Chenopodium album L., and Portulaca oleracea L., weed of Portulaca oleracea L. reduced adlay yield most by 182.6kg/10a and it was judged to be the most injurious weed to adlay production. Among four weed control systems, which are one herbicide treatment, one herbicide treatment + one cultivating work with cultivator, two times cultivating work with cultivator and two times hand-weeding, the control system of 'one herbicide treatment + one cultivating work with cultivator' showed the lowest amount of weed growth by 7.34 weeds per $m^2$ in comparison with control plot of 35.00 weeds per $m^2$. Among four weed control systems, the system of 'two times hand-weeding' had much more amount of light penetration in adlay canopy with 791.9 mol than any other systems.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.30-39
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• 1989

Forage productivity of cropping systems of rye - silage corn, silage corn - oats, silage corn - rape was studied in the south-eastern part of Korea where rice black-streaked dwarf virus(RBSDV) infection of corn are severe. Rye(cv. Paldanghomil) was planted on Oct. 20 of 1986 and harvested 10 times from April 5 to May 5 at the 5-day intervals in 1987, corn (cv. Suweon 19 and Jinjuok) was planted 5 times from April 5 to May 15 at the 10-day intervals in 1987, and oats(cv. Megwiri) and rape (cv. Velox) were planted 4 times from Sept: 4 to 25 at the 7-day intervals and harvested 4 times from Nov. 10 to Dec. 10 at the 10-day intervals in 1987. Considering yield, nutrition value, and in vitro dry matter digestibility (IVDMD), forage productivity of the cropping systems was compared. As harvesting time of rye delayed, plant height, dry matter(DM) yield, percent DM, crude fiber, and digestible DM yield increased, but crude protein, crude fat, and IVDMD decreased. However, nitrogen free extract was not different among the harvesting dates. As planting date of corn delayed, RBSDV infection rate increased. but DM yield of silage decreased. However, silage yield of Jinjuok was higher, but RBSDV infection rate was lower compared with Suweon 19 at all planting dates. DM yield of oats and rape decreased as planting date delayed. However, at Sept. 4 and 11 plantings yield of oats on Nov. 10 was much lower than that of rape, but the differences in yield between two crops decreased with delayed harvesting, and yield was similar on Dec. 10. A cropping system harvesting rye around April 20 and followed by planting corn in late April was best among the rye-corn systems considering yield and nutrition value of both crops. However, among the corn-oats or corn-rape cropping systems early April planting of corn and followed by early Sept. planting of oats or rape showed best results with similar yield potential of the best rye-corn cropping system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.178-184
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• 1992

The changes in contents of chlorophyll and free proline in the seedling leaves of ten rice cultivars as affected by salt stress were checked in order to obtain the basic information on the judgement of the degrees of salt injury. The difference in salt injury among the cultivars was clearly observed about 25 days after 6% salt treatment. Chlorophyll content was decreased in both Gayabyeo and Taebaegbyeo for 14 days after different salt treatment as salt concentration was increased and the decreased tendency was much higher in Taebaegbyeo than in Gayabyeo over 0.4% salt concentration. Chlorophyll content in Gayabyeo after 0.6% salt treatment was decreased slowly, while in Taebaegbyeo, deminished very rapidly as time progressed, therefore it decreased by about 16% in Gayabyeo and 67% in Taebaebyeo compared to the control at 20 days, respectively. The relationship between chlorophyll content and the degrees of salt injury in ten rice cultivars showed significant negative correlation at 10 day after 0.6% salt treatment. Free proline content in Gayabyeo was increased gradually for 14 days after different salt treatment as salt became higher, while in Taebaebyeo, it was increased rapidly under 0.6% but rather decreased under 0.8% salt concentration. Particularly, it was much higher Taebaegbyeo than in Gayabyeo under salt concentration from 0.4 to 0.6%. Free proline content in Gayabyeo after 0.6% salt treatment was increased from 15 days, on the other hand in Taebaegbyeo, it was increased from 5 days, but rather decreased from 20 days, and it was 6 times higher in Taebaegbyeo than in Gayabyeo at 10 days. There was significant positive correlation between free proline content and the degrees of salt injury in ten rice cultivars at 10 days after 0.6% salt treatment. From the above results, chlorophyll and free proline content may be used as an indicative character of intensity of salt stress as well as varietal difference in resistance to salt stress in the seedling stage.