• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.2
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• pp.113-123
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• 2020

Global climatic change and increasing climatic instability threaten crop productivity. Due to climatic change, drought stress is occurring more frequently in crop fields. In this study, we investigated the effect of treatment with hydrogen peroxide (H₂O₂) before leaf development on the growth and yield of sorghum for minimizing the damage of crops to drought. To assess the effect of H₂O₂ on the growth of sorghum plant, 10 mM H₂O₂ was used to treat sorghum leaves at the 3-leaf stage during growth in field conditions. Plant height, stem diameter, leaf length, and leaf width were increased by 7.6%, 9.6%, 8.3% and 11.5%, respectively. SPAD value, chlorophyll fluorescence (Fv/Fm), photosynthetic rate, stomatal conductance, and transpiration rate were increased by 3.0%, 4.9%, 26.0%, 23.4% and 12.7%, respectively. The amount of H₂O₂ in the leaf tissue of sorghum plant treated with 10 mM H₂O₂ was 0.7% of the applied amount after 1 hour. The level increased to approximately 1.0% after 6 hours. The highest antioxidant activity measured by the Oxygen Radical Absorbance Capacity assay was 847.3 µmol·g^-1 at 6 hour after treatment. However, in the well-watered condition, the concentration of H₂O₂ in the plant treated by the foliar application of H₂O₂ was 227.8 µmol·g^-1 higher than that of the untreated control. H₂O₂ treatment improved all the yield components and yield-related factors. Panicle length, plant dry weight, panicle weight, seed weight per plant, seed weight per unit area, and thousand seed weight were increased by 8.8%, 18.0%, 24.4%, 24.7%, 29.9% and 7.1%, respectively. Proteomic analysis showed that H₂O₂ treatment in sorghum increased the tolerance to drought stress and maintained growth and yield by ameliorating oxidative stress.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.1
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• pp.2177-2190
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• 1971

This experiment was made to determienthe effect of various soil moisture contents in simulated drought conditions on different stages of rice growth. The drought conditions were developed at such three rice-growing stages as transplanting, immediately after transplanting and young ear forming. Three different lengths of drought periods, which are ten days, twenty days and thirty days, were applied for each growing stage of rice. The rice variety used this experiment is Nong-rim 29. This experiment was conducted at the university farm of the Kon-Kuk University during the period of $1968{\sim}1970$. Three reprications for each of 12 treatments and split plot design were employed in this study. Bottomless wood square boxes, $1^m{\times}1^m{\times}1^m$, were burried in the test plot and box top was covered with poloyethylene sheets to avoid natural rainfall drops. Standard plots were irrigated continuously with a water depth of 40mm/day and those of drought treatments were irrigated continuously up to the beginning of the planned drought period, and they were irrigated again with a depth of 40mm/day up to the maturing stage of rice. Other methods for rice raising followed those methods developed by the Field Crops Experiment Station of the Office of Rural Development. During this experiments, climatic conditions in regard to rainfalls, sunshine hours, and temperatures were observed. According to this observation, those values measured deviate slightly from the annual means. However the growing condition of rice plants were normal. The pH value of irritation water is nearly neutral, and soils in the test plots are relatively fertile, being similar to ordinary paddy soils. Analysis of variances for number of stalks, plan-height, ear sprouting date, length of stalks, ear length, number of ears per plant, fertility, grain weitght, weight of plant, and yield were carried out. The variances for plant height, ear sprouting date, length of stalk ear length, and yield has statistical significance under drought treatments applied at three different growing stages. The variance showing the effect of lengths of drought period is highly significant for all the treatments studied except that of grain weight. The interaction between drought periods and drought treatments at different growing stages is significant for plant height, stalk length, ear length, number of ears, fertility and yield, these results indicated that droughts at different growing stages have influence on plant height, ear length, yield, and length of drought period also has strong influence on all factors studied except grain weight. The combination of drought treatments at different rice growing stages and lengths of drought periods has different effects on various agronomic characteristics, including yield. Plant height under drought treatment practiced at transplanting stage is the lowest, and drought treatment applied immediately after transplanting resulted in the least number of stalks. The effect of different lengths of drought periods on plant height and number of stalks depends signis ficantly on increasing days of drought. Ear sprouting date tends to be delayed for one or two days undedrought treatments at transplanting period and with increasing days of drought. Better yield is secured in drought treatment applied immediately after transplanting. Adverse effect war observed when drought treatment was applied at ear forming period. These effects may be attributed to the alternation of irrigation and drought causing vigorous root activity. In general, yield linearly decreases as the length of the drought period increases. The results obtained in this study demonstrate that, in order to mimimize damage due to drought, and, to save irrigation water, paddy fields, immediately after transplanting, may be not irrigated, since there is sufficient moisture in the soil, and that sufficient irrigation water should be applied again in the ear forming stage of rice plant.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.4
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• pp.423-430
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• 2014

In this study, the antioxidative effects for the extracts of purple sweet potato (Ipomoea batatas L. Lam.) were investigated. The purple sweet potato was extracted with 70% ethanol and the ethyl acetate fraction was obtained from the extracts. The yields of extract and ethyl acetate fraction were 39.2% and 3.49% per dried powder, respectively. To confirm the antioxidative effects of the extracts, free radical scavenging activities (1,1-diphenyl-2-picrylhydrazyl), total antioxidant capacity by luminol-dependent chemiluminescence assay and the protective effects against reactive oxygen species (ROS) in erythrocytes were measured. Free radical scavenging activities ($FSC_{50}$) of the 70% ethanol extract and ethyl acetate fraction were $90.16{\mu}g/mL$ and $7.69{\mu}g/mL$, respectively. The free radical scavenging activity of ethyl acetate fraction was higher than that of (+)-${\alpha}$-tocopherol ($8.98{\mu}g/mL$). Total antioxidant capacities ($OSC_{50}$) of the 70% ethanol extract and ethyl acetate fraction were $5.75{\mu}g/mL$ and $1.92{\mu}g/mL$, respectively. The capacity of ethyl acetate fraction was similar to L-ascorbic acid, known as a prominent water soluble antioxidant ($1.50{\mu}g/mL$). The cellular protective effects of the ethyl acetate fractions on the $^1O_2$-induced cellular damage of human erythrocytes were increased in a concentration dependent manner ($5{\sim}50{\mu}g/mL$). The ${\tau}_{50}$ value in $5{\mu}g/mL$ was 45.6 min which was higher than that of (+)-${\alpha}$-tocopherol in all concentrations. These results indicate that the ethyl acetate fraction of purple sweet potato (I. batatas) has the excellent antioxidative capacity and could be applicable to anti-aging cosmeceutical ingredients for skin aging inhibition.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.73-84
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• 2018

Recently, the importance of flame retardation treatment technology has been emphasized due to the increase in urban fire accidents and fire damage incidents caused by building exterior materials. Particularly, in the utilization of wood-based building materials, the flame retarding treatment technology is more importantly evaluated. An Intumescent system is one of the non-halogen flame retardant treatment technologies and is a system that realizes flame retardancy through foaming and carbonization layer formation. To apply the Intumescent system, composite material was prepared by using Ethylene vinyl acetate (EVA) as a matrix. To enhance the flame retardant properties of the Intumescent system, a nano-clay was applied together. Composite materials with Intumescent system and nano - clay technology were processed into sheet - like test specimens, and then a new structure of cross laminated timber with improved flame retardant properties was fabricated. In the evaluation of combustion characteristics of composite materials using Intumescent system, it was confirmed that the maximum heat emission was reduced efficiently. Depending on the structure attached to the surface, the CLT had two stages of combustion. Also, it was confirmed that the maximum calorific value decreased significantly during the deep burning process. These characteristics are expected to have a delayed combustion diffusion effect in the combustion process of CLT. In order to improve the performance, the flame retardation treatment technique for the surface veneer and the optimization technique of the application of the composite material are required. It is expected that it will be possible to develop a CLT structure with improved fire characteristics.

• Korean Journal of Agricultural Science
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• v.8 no.1
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• pp.90-96
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• 1981

To design more efficient agricultural machinery, the accurately measuring system among many other factors is essential. A light-beam oscillographic recorder is generally used in measuring dynamic strain but it is not compatible with the extremely high speed measuring system such as 1,000 m/s, also is susceptable to damage due to vibration while using the system in field. The recorder used light sensitive paper for strip chart recording. The reading and analysis of data from the strip charts is very cumbersome, errorneous and time consuming. A microcomputer was interfaced with A/D converter, microcomputer program was developed for measuring, system calibration was done and the strain generated from a cantilever beam vibrator was measured. The results are summarized as follows. 1. Microcomputer program was developed to perform strain measuring of agricultural machine elements and could be controled freely the measuring intervals, no. of channels and no. of data. The maximum measuring speed was $62{\mu}s$. 2. Calibration the system was performed with triangle wave generated from a function generator and checked by an oscilloscope. The sampled data were processed using HP 3000 minicomputer of Chungnam National University computer center the graphical results were triangle same as input wave and so the system have been out of phase distorsion and amplitude distorsion. 3. The strain generated from a cantilever beam vibrator which has free vibration period of 0.019 second were measured by the system controlled to have l.0 ms of time interval and its computer output showing vibration curve which is well filted to theoretical value. 4. Using microcomputer on measuring the strain of agricultural machine elements could not only save analyzing time and recording papers but also get excellent adaptation to field experiment, especially in measurement requiring high speed and good precision.

• Journal of the Korean earth science society
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• v.39 no.3
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• pp.241-249
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• 2018

As the international trade increases, vessel traffics around the Korean Peninsula are also increasing. Maritime accidents hence take place more frequently in the southern coast of Korea where many big and small ports are located. Accidents involving ship collision and sinking result in a substantial human and material damage as well as the marine environmental pollution. Therefore, it is necessary to locate the ships quickly when such accidents occur. In this study, we suggest a new ship detection index by comparing and analyzing the reflectivity of each channel of the Korea MultiPurpose SATellite-2 (KOMPSAT-2) images of the area around the Gwangyang Bay. A threshold value of 0.1 is set based on a histogram analysis, and all vessels are detected when compared with RGB composite images. After selecting a relatively large ship as a representative sample, the distribution of spatial reflectivity around the ship is studied. Uniform shadows are detected on the northwest side of the vessel. This indicates that the sun is in the southeast, the azimuth of the actual satellite image is $144.80^{\circ}$, and the azimuth angle of the sun can be estimated using the shadow position. The reflectivity of the shadows is 0.005 lower than the surrounding sea and ship. The shadow height varies with the position of the bow and the stern, perhaps due to the relative heights of the ship deck and the structure. The results of this study can help search technology for missing vessels using optical satellite images in the event of a marine accident around the Korean Peninsula.

• Tuberculosis and Respiratory Diseases
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• v.65 no.3
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• pp.183-190
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• 2008

Background: The control of active pulmonary tuberculosis is still an issue in community medicine. But there are also considerable needs for supportive management of symptomatic patients with post-tuberculous destroyed lung. Few studies have evaluated clinical characteristics and health-related quality of life in patients with post-tuberculous destroyed lung. Methods: We evaluated lung function, exercise tolerance, HRCT and health-related quality of life measurements using the Korean version of St. George's Respiratory Questionnaire (SGRQ) in 22 patients with parenchymal damage to more than a half of one lung due to pulmonary tuberculosis. Results: In the pulmonary function test, mixed defects and obstructive defects were observed in 10 (45.0%) and 9 (40.9%) of patients, respectively. In the cardiopulmonary exercise test, the mean $VO_2max%$ predicted ($39.0%{\pm}10.9%$) and $O_2$ pulse% predicted ($61.3%{\pm}13.6%$) were markedly decreased. In the SGRQ, the impact score (mean $27.8{\pm}18.5$) was significantly lower than the symptom score (mean $53.9{\pm}20.9$) or activity score (mean $50.8{\pm}27.3$) (p<0.05, p<0.01). Cronbach's alpha coefficient value for reliability was more than 0.7 for each subscale and total score. The total score showed a significant negative correlation with $FEV_1%$ predicted (r=-0.46, p<0.05) and $SaO_2$ (r=-0.60, p<0.05). On HRCT, a median of 9 (range 5~15) bronchopulmonary segments were destroyed by less than half, which significantly correlated with SGRQ total score (r=-0.52, p=0.02). Conclusion: The reliability and validity of the Korean version of the SGRQ was acceptable for the measurement of health-related quality of life in patients with post-tuberculous destroyed lung.

• Journal of Korean Society of Forest Science
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• v.61 no.1
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• pp.60-68
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• 1983

Ever since the day of pre-modernized society where the farming skill had been in the stagnant condition, the common farmwoodlands have been utilized in common (collectivelly) by villagers in order to harvest farmwoodlands and fuelwoods. Later, during the process of modernization, most of the common farmwoodlands were transferred into national or public forests by the administrative enforcement, but there were still various types of village (common) forests such as the common forests owned by joint owners, village block associations, village forest productive societies, Village Forestry Association(V.F.A.), and the national or public forests leased to V.F.A. As Village Forestry Association is organized with a few villages, each of common forests ow nod to the villages is obliged to be diversely controlled by other managers than the chief of V.F.A. Therefore, it is to be desired that the control of common forests should be under Gun Forestry Association Union. While the rate of the use of common forests for fuelwoods and cemetery has been considerably high, villagers wish to promote the timber forest establishment through the collective management by their improved farming skills and economical situations. In these present circumstances the village forest productive societies should be guided to work in closer cooperation with Gun Forestry Association Union. Since the management of common forests is still extensive, it still remains in the semi-management condition under which we can not find any management plan or measure to control forest damage. Especially the small area common forests should have appropriate size for the joint management. This will promote the forest productivity through the lease for reforestation of disposable national forests or public county forests and the contracts for profit sharing. Today owing to increasing forest value, frequent dispute has occurred on the common right telated to the village forests and rationalization of forest management has been disregarded. If a necessary measure were taken to control the dispute such as transferring the registeration right of ownership to the village forest productive society, the confidence of local inhabitants can be regained and the productivity of forests can be naturally increased.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.293-302
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• 2014

This study was carried out to develop rain shelter which can make an appropriate size and environment for Chinese cabbage rainproof cultivation. Fifty three farms with chinese cabbage rainproof cultivation system have been investigated to set up width and height of rain shelter. Mostly the width of 6m was desired for rain shelter and the height of 1.6m for their eaves, so these values were chosen as the dimensions for rain shelter. After an analysis of their structural safety and installation costs by the specifications of the rafter pipe, Ø$25.4{\times}1.5t$ and 90cm have been set as the size of rafter that such size costs the least. This size is stable with $27m{\cdot}s^{-1}$ of wind velocity and 17cm of snow depth. Therefore it is difficult to apply this dimension to area with higher climate load. In order to sort out such problem, the rain shelter has been designed to avoid damage on frame by opening plastic film to the ridge. Once greenhouse band is loosen by turning the manual switch at the both sides of rain shelter and open button of controller is pushed then switch motor rises up along the guide pipe and plastic film is opened to the ridge. Chinese cabbage can be damaged by insects if rain shelter is opened completely as revealed a field. To prevent this, farmers can install an insect-proof net. Further, the greenhouse can be damaged by typhoon while growing Chinese cabbage therefore the effect of an insect-proof net on structural safety has been analyzed. And then structural safety has been analyzed through using flow-structure interaction method at the wind condition of $40m{\cdot}s^{-1}$. And it assumed that wind applied perpendicular to side of the rain shelter which was covered by insect-proof net. The results indicated that plastic film was directly affected by wind therefore high pressure occurred on the surface. But wind load on insect-proof net was smaller than on plastic film and pressure distribution was also uniform. The results of structural analysis by applying pressure data extracted from flow analysis indicated that the maximum stress occurred at the end of pipe which is the ground part and the value has been 54.6MPa. The allowable stress of pipe in the standard of structural safety must be 215 MPa or more therefore structural safety of this rain shelter is satisfied.

• Clinical and Experimental Pediatrics
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• v.49 no.8
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• pp.889-894
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• 2006

Purpose : Asthma is characterized by the presence of airway hyperresponsiveness(AHR) and inflammation. The extensive eosinophil infiltration into the lung is the hallmark of asthma and contributes to the damage of respiratory epithelium during late phase airway responses. Eotaxin is the major eosinophil chemoattractant found in bronchoalveolar lavage(BAL) fluid of allergic inflammation. IL-13 has been known to induce the expression of exotaxin and eosinophilia. IL-13 also induces airway inflammation, mucus production and leads to marked fibrosis, airway remodeling and AHR. We investigated whether serum IL-13 levels can reflect the presence of airway hyperresponsiveness in children with asthma, and the relationship between serum IL-13 and eotaxin levels. Methods : Using sandwich enzyme-linked immunosorbent assay, the serum IL-13 and eotaxin levels were measured in 13 atopic asthmatics, 5 atopic non-asthmatics and 12 control subjects. Metacholine challenge tests were performed in all subjects. Airway hyperresponsiveness to metacholine was expressed as provocative concentration of metacholine causing a 20% fall in FEV1[$PC_{20}mg/mL$]. $PC_{20}$ value of 25 mg/mL was used as a cut-off for defining a AHR. Results : Serum IL-13 levels showed positive correlation with eotaxin levels. Serum IL-13 and eotaxin levels showed no differences among atopic asthmatics, atopic non-asthmatics and control subjects. And there were no differences serum IL-13 and eotaxin levels in children with and without AHR and atopy. Serum IL-13 and eotaxin levels did not correlate with $logPC_{20}$ levels. Conclusion : IL-13 is closely related to the eotaxin release. But serum IL-13 and eotaxin per se can't predict the severity of airway hyperresponsiveness. IL-13 and eotaxin may have local effect on respiratory epithelium or there can be some factors to induce airway hyperresponsiveness other than serum IL-13 in asthmatic airways.