• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.146-152
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• 2005

The activated carbon was produced from Sancheong bamboo by carbon dioxide gas activation methods. The carbonization of raw material was conducted at $900^{\circ}C$, and $CO_2$ activation reactions were conducted under various conditions: activation temperatures of $750-900^{\circ}C$, flow rates of carbon dioxide $5-30cm^3/g-char{\cdot}min$, and activation time of 2-5 h. The yield, adsorption capacity of iodine and methylene blue, specific surface area and pore size distribution of the prepared activated carbons were measured. The adsorption capacity of iodine (680.8-1450.1 mg/g) and methylene blue (23.5-220 mg/g) increased with increasing activation temperature and activation time. The adsorption capacity of iodine and methylene blue increased with the $CO_2$ gas quantity in the range of $5-18.9cm^3/g-char{\cdot}min$. But those decreased over those range due to the pore shrinkage. The specific volume of the mesopore and macropore of bamboo activated carbon were $0.65-0.91cm^3/g$. Because of this large specific volume, it can be used to the biological activated carbon process. Bamboo activated carbon phisically adsorbed the $CO_2$ of maximum 106 mg/g-A.C in the condition of 90% $CO_2$ and adsorption temperature of $20^{\circ}C$. The $CO_2$ adsorption ability of bamboo activated carbon was not changed in the 5 cyclic test of desorption and adsorption.

• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.4
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• pp.82-95
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• 1980

This paper complies the results of the studies so far made on the subsoil improvement of subsurface drainage systems for wet paddy fields (those were located in the Gum-Ho area in Kyung Buk province) which had poor permeability and a high water table. In general, a drainage problem is an excess of water on the ground surface which can effect the productivity and bearing capacity of the soil. With drain pipe systems, (According to their depths and spacing) it may be possible to correct that problem. The experimentation consisted of three test plots, two of which included drain pipe systems with varing depths and width spacing of the pipes. The third plot (C) was an ordinary plot being exempt of a drain pipe system. In detail, the depth of plot A was 80 cm, and the width spacings began at 2. Om and increased by 2. Om up to 10. 0m. The depth of plot B was 60cm and the width spacing was the same as plot A. These tests were performed to research specific details; such as crop yeild, bearing capacity of the soil, the amount of underdrainage, surface cracks, root distribution, the water table level, the consumptive water depth and the soil moisture content. The test period lasted three years, from 1977 thru 1979. The results obtained were as follows: 1. During the test period, the weather conditions for the area tested were in accordance with the annual average for that area. Furthermore the precipitation factor during the spring cultivation season, the intermediate drainage period and the harvest drainage period was of optimum conditions for controling surface cracks, because of less precipitation than evaporation. 2. The difference in the level of the ground water table in plots A and B was hardly noticable, but the difference in the test plots and the ord. plot was greatly noticable. The test plots (A, B) were 30 to 40cm lower than the ordinary plot. On the whole, the ground water table of the ord. plot always stayed at a level of 15-20cm beneath the surface of the soil, the ground water table of the test plot A showed The difference in the depth of the pipe lower than the test plot B, while the test plots showed a remarkable descending effect. 3. The soil temperature in plot A was slightly core than in plot B with a difference of 0. 47$^{\circ}$C, but plot A was 1. 6$^{\circ}$C higher than the ord. plot during the flooding period, but after drainage the temperature difference climed to 2. 0$^{\circ}$C. 4. During the 3rd test year, the values of the cracks were recorded with the values of 59cm in plot A, 42cm in plot B and 15cm in the ordinary plot. Plots A and B had increased 2.5 times the value of the first year while the ordinary plot had remained the same. 5. The root weight of the rice was measured at a value of 77.2 gr. for plot A, 73.5 gr. for plot B and 65.3 gr. for the ord. plot. Therefore, the root growths in plots A and B were much more energetic than in the ord. plot. 6. The consumptive water depth measured during the 3rd year resulted in the values of 26. 0mm per day for plot A, and 24.9 mm per day for plot B, respectively. Therefore, both plot A and plot B maintained the optimum consumptive water depths, but the ordinary plot only obtained the value of 12.3 mm per day, which clearly showed less than the optimum consumptive water depth which is 20 to 30 mm/day. 7. The soil moisture content is in direct relationship to the ground water level. During drainage, test plot A decreased in its ground water level much more rapidly than the other two plots. Therefore, plot A had a much less soil moisture content. But this decreased water level could be directly effected by the weather conditions. 8. The relationship between the bearing capacity and the soil moisture content were directly inversely proportional. It can be assumed that the occurence of soil creaks is limited by the soil moisture content. Therefore, the greater the progress of the surface creaks resulted in a greater bearing capacity. So, tast plot A with a greater amount of surface cracks than the other test plots resulted in a greater bearing capacity. But, the bearing capacity at the harvest season could be effected by the drainage during the intermediate drainage period and by the weather conditions. 9. Comparing the production of the test plots to the ord. plot; there was an increased value of 840kg for plot A, 755kg for plot B and 695kg for the ord. plot in the rough rice. Therefore, plot A had an increase of 20% over the ordinary plot. The possibility of producing double crops was investigated. The effects on barley production in the test plots showed a value of 367kg per 10 acres, which substantiated the possibility of double crops because that value showed an increased value over the average yearly yield for those uplands. 10. So as a result, it can be recommended that by including a drain pipe system with the optimum conditions of an (80cm centimeter) depth and a (l0m) spacing will have a definite positive effect on the over all production capacity and quality of wetpaddy fields.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.59-67
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• 1983

An experiment on the rearing of tilapia stocked in closed recirculating tanks eliminating biological filter beds was carried out at the Fish Culture Experiment Station of the National Fisheries University of Pusan, from May 18 through October 21, 1982, and the growth rates, feed conversion, water quality, spawning prevention and space utilization efficiency were discussed. Finally discussed is the feasibility on the establishment of commercial production units. On the water quality, the water temperature ranged from $22.8^{\circ}C\;to\;29.1^{\circ}C$, and total ammonia arround 10 ppm or slightly up. Maintaining phytoplankton bloom was not successful probably because of the active consumption by the heavily stocked tilapia. Several attempts were made by changing the culture water with green water from a nearby earthen pond with results of fading-away in a couple of days. Feed conversions were relatively high ranging from 0.9 to 1.2 except for experiment 1 when the fish were not fully recovered from weakened wintering state. The feed used was partly laboratory prepared $25\%$ protein diet and mostly commercially available $39\%$ protein carp feed. Spawning was completely controlled during the experiment, resulting from density effect, which ranged from 10kg to 40.7kg per square meter with water depth of 0.5 to 0.6m. Space utilization efficiency was very high. Daily net production from the experiment division 3, which showed the highest result, was 6.206 kg per tank, which is calculated 3,235 metric tons per hectare per year, This time, water temperature ranged from 27.8 to $29.1^{circ}C$, average being $28.4^{circ}C$, and total ammonia arround 10 ppm. An estimation for the commercial set-up of the production system based on the results of experiment divisions which had initial stocking rate $15\;kg/m^2$ or up, is made. If the total facility, 8 tanks comprising $56\;m^2$ in surface area, is used for the present study, the yield would become 5,639 kg from 200 day rearing, which would be possible under double sheets vinyl house without additional heating, and it is thought feasible in the economic view point, when 10 or more units are operated.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.361-367
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• 1984

In previous paper(Lee et al., 1984), preparation formula and processing conditions of the fish meat (mackerel) paste using dielectric heating were described, that included the proper shape and size of product and the conditions of dielectric heating, hot air dehydration, and heating with electric heater to yield the minimum expansion and case hardening during heating and to controll the final rater activity of 0.86 to 0.83 accompanying with a complete reduction of viable cells and good texture. In present study, changes in VBN, pH, total plate count, water activity, texture, the loss of available lysine, color indexes, TBA value, and the content of TI were determined to assess the quality stability and shelf-life of the product during the storage for 35 days at $5^{\circ}C\;and\;25^{\circ}C$, respectively. And the effect of vacuum sealing and hot water treatment before storage on the storage stability of product was also mentioned. As the product was vacuum packed in K-flex film bag, heat treated in boiling water for 6 minutes, and stored, water activity was maintained 0.86 to 0.84 for 35 days regardless of storage temperature, and the increase of total plate count was negligible in case of $5^{\circ}C$ storage while tended to gain slightly after 25 days at $25^{\circ}C$ storage. Changes in VBN was also minimum with an increase of 1.5 mg/100g at $5^{\circ}C$ and 7.0mg/100g at $25^{\circ}C$, but in case of unpacked sample, it was 24.5mg/100g at $5^{\circ}C$ and 42.4 mg/100g at $25^{\circ}C$ even after 7 days. In textural property hardness tended to increase after 28 days and folding test score was down to A or B from AA grade. The loss of available lysine was $7.5\%\;at\;5^{\circ}C$ and $17.0\%\;at\;25^{\circ}C$ but brown color was not deeply developed as the color index score indicated. TBA value was not increased at $5^{\circ}C$ while it tended to increase rapidly after 30 days at $25^{\circ}C$. Changes in TI content was not obvious except that it showed a tendency of increase at the end of storage as well as in the change of lysine and TBA value. It is concluded from the results that the quality of the product, pasteurized and water activity controlled by dielectric heating, and vacuum packed in K-flex film would be stable for more than 35 days at $5^{\circ}C$ and at least 25 days even at room temperature.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.251-256
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• 2012

Etherification of n-butanol to di-n-Butyl Ether was carried out over Keggin $H_{3+x}PW_{12-x}Nb_xO_{40}$ (x=0, 1, 2, 3) and $H_{6+x}P_2W_{18-x}Nb_xO_{62}$ (x=0, 1, 2, 3) Wells-Dawson heteropolyacid catalysts. Niobium-substituted Keggin and Wells-Dawson heteropolyacid catalysts with different niobium content were prepared. Successful preparation of the catalysts was confirmed by FT-IR, ICP-AES, and $^{31}P$ NMR analyses. Their acid properties were determined by $NH_3$-TPD (Temperature-Programmed Desorption) measurements. Heteropolyacid catalysts showed different acid properties depending on niobium content in both series. The correlation between acid properties of heteropolyacid catalysts and catalytic activity was then established. Acidity of Keggin and Wells-Dawson heteropolyacid catalysts decreased with increasing niobium content, and conversion of n-butanol and yield for di-n-butyl ether increased with increasing acidity of the catalysts, regardless of the identity of heteropolyacid catalysts (without heteropolyacid structural sensitivity). Thus, acidity of heteropolyacid catalysts served as an important factor determining the catalytic performance in the etherification of n-butanol to di-n-Butyl Ether.

• Journal of the Korean Wood Science and Technology
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• v.9 no.3
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• pp.7-15
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• 1981

A Japanese larch has been reforested very much in Korea, but it is not used as a wood resources for paper pulp by now. So this study is carried out to utilize the larchwood for paper pulp manufacture through the Asplund pulping process. The experiment on increasing in the brightness of the pulp is made through the addition of $MgSO_4$, $ZnSO_4$, $Al_2(SO_4)_3$, and KI as a cellulose stabilizer in chip treatment with caustic soda which is followed by high-temperature defibration and conventional peroxide bleaching (5% NaOH plus 2% additive salt per wood in cold pretreatment), or in high-consistency (30%) pulp bleaching of hydrogen peroxide and peracetic acid (100% acitve oxygen per lignin) for conventional one. The results obtained are as follows: 1. The solution of 0.5% additive salts had different pH by the sort of bases that was pH 5.7 in $MgSO_4$, liquor, pH 4.9 for $ZnSO_4$, and pH 2.9 for $Al_2(SO_4)_3$, and in the precepitation of bases which ranged to pH 6-13 for $MgSO_4$, pH 5-12 for $ZnSO_4$, and pH 3-10 for $Al_2(SO_4)_3$. 2. The cellulose stabilizer affective in high-consistency peroxide bleaching was KI, $MgSO_4$, and $ZnSO_4$, but has made a little improvement in de lignification and brightness of pulp in comparison with no addition. 3. The higher alkalinity in the chip treatment has made the higher strength and brightness of larchwood Aspiund pulp instead of downing the pulp yield. And the effective compound for cellulose stabilizer in caustic soda pretreatment of chip was $ZnSO_4$, $Al_2(SO_4)_3$ and KI in order for the conventional peroxide bleaching after Asplund pulping. 4. Therefore, the more effective additives for cellulose stabilization in high-temperature defibration of larchwood suppose to be $ZnSO_4$, $Al_2(SO_4)_3$, and KI, while KI and $MgSO_4$ for peroxide bleaching.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.1018-1023
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• 2010

Climatic change was observed and analyzed in view of impacts on agricultural ecosystem, inter alia on rice cropping. The changed climate gave rise to earlier transplanting of rice seedling and later harvest after 40 years. Also phenological change and prolonged growth duration was observed. The meteorological data was selected from the standardized climatological data of 30 year normals of 1960s and 2000s, which were published by Korea Meteorological Administration. Development stages and growing periods of rice crop were compared by analyzing critical and optimum temperatures of each growth stage during these two periods. The first appearance date of $15^{\circ}C$ was ranged from Apr. 29 to May 23 in the year-normals of 1960s and it varied from Apr. 24 to May 16 in the normals of 2000s. The difference of the first appearance date of $15^{\circ}C$ was 0~10 days earlier in the year-normals of 2000s than the 1960s. The last harvesting date was determined to be the last appearance date of mean air temperature $15^{\circ}C$. The difference in the last appearance date of $15^{\circ}C$ was 1 to 13 days later in the year-normals of 2000s than in 1960s. The plant height of a rice variety, Hwayoung-byeo was 101~109 cm in 4 local areas, Seoul, Kangneung, Kwangju and Daegu. The plant height became 1~4 cm taller under warm condition. Rice grain yields estimated with daily weather data for the year-normals of 1960s and 2000s were 453~580 kg $10a^{-1}$ and 409~484 kg $10a^{-1}$ respectively. Rice grain yield of the former period was 50~100 kg $10a^{-1}$ higher than that hat in the later period.

• Journal of Food Hygiene and Safety
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• v.36 no.5
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• pp.447-453
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• 2021

In this study, the effectiveness of physical control technology, a combined light sterilization (LED, UV) and hot water treatment in reducing Aspergillus ochraceus for food production environment was investigated. In brief, 1 mL aliquot of A. ochraceus spore suspension (10^7-8 spore/mL) was inoculated onto stainless steel chips, which was then dried at 37℃, and each was subjected to different physical treatment. Treatments were performed for 0.5, 1, 2, 5, 8, and 11 hours to reduce the strains using a light-emitting diode, but no significant difference was confirmed among the treatments. However, a significant reduction was observed on the chips treated with UV-C exposure and hot water immersion. After being treated solely with 360 kJ/m² of UV-C on stainless steel chip, the fungi were significantly reduced to 1.27 log CFU/cm². Concerning the hot water treatment, the initial inoculum amount of 6.49 log CFU/cm² was entirely killed by immersion in 83℃ water for 5 minutes. Maintaining a high temperature for 5 minutes at the site is difficult. Thus, considering economic feasibility and usability, we attempted to confirm the appropriate A. ochraceus reduction conditions by combining a relatively low temperature of 60℃ and UV rays. With the combined treatments, even in lukewarm water, A. ochraceus decreased significantly through the increases in the immersion time and the amount of UV-C irradiation, and the yield was below the detection limit. Based on these results, if work tools are immersed in 60℃ lukewarm water for 3 minutes and then placed in a UV sterilization device for more than 10 minutes, the possibility of A. ochraceus cross-contamination during work is expected to be reduced.

• Journal of the Korean Society of International Agriculture
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• v.30 no.4
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• pp.300-304
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• 2018

'Bokha' is a new strawberry (Fragaria x ananassa Duch.) cultivar, which was released by the Highland Agriculture Research Institute in 2016. The 'Bokha' cultivar originated from a cross between 'Goha' and 'Saebong No. 3' that showed excellent ever-bearing characteristics, including continuous flowering habit and high soluble-solids contents under long-day and high temperature conditions in 2011. This cultivar was initially named 'Saebong No. 8' after examining its characteristics and productivity in summer culture from 2013 to 2015. After regional adaptability tests in 2016, 'Bokha' was selected from Saebong No. 8 as an elite cultivar. The general characteristics of 'Bokha' include semispreading type, elliptical leaves, and moderately vigorous growth. The fruits are conical in shape, and red in color. 'Bokha' plants have 32.7 leaves, 9.9 more than 'Goha' plants. The soluble-solids content of 'Bokha' was 9.2%, which was 0.2% higher than that of 'Goha'. The average fruit weight of 'Bokha' was about 9.5g and the marketable yield was $27,701kg{\cdot}ha^{-1}$, 72% higher than 'Goha'. 'Bokha' is suitable for tropical and subtropical zone cultivation as a high soluble solids contents cultivar, because it shows continuous flowering habit under long-day and high temperature conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.2
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• pp.120-129
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• 2021

Securing a range of wheat resources is of particular importance with respect to wheat breeding, as it provides a broad genetic foundation. Although wheat breeders have used different wheat germplasms as material resources in current breeding systems, the traits of most germplasms collected from foreign countries differ from the unique traits that have evolved in the Korean environment. In this study, conducted over a 2-year period (2018 and 2019), we therefore evaluated the agricultural traits 1,967 wheat germplasms collected not only in Korea but also worldwide. During the period from sowing to February, the average temperature in 2019 was greater than 1℃, whereas from March to June, the average temperature was approximately 0.9℃ higher in 2018. Compared with the growth recorded in 2018, the stem length in 2019 increased by approximately 20 cm in 2019, and there were notable differences heading date and maturation between 2018 and 2019. In 2019, the heading dates of 973 and 713 wheat resources were earlier and later than those in 2018, respectively. Moreover, stem length was found to be highly correlated with the heading date and maturation. In Korea, where the rainy season and tine of rice transplantation overlap with the time of wheat harvest, early flowering time with high grain yield has been the most important selection target with respect to wheat breeding. We anticipate that the findings of this study will provide would use a foundation for the selection of elite materials and the development of resource core-sets for Korean wheat breeding programs.