Ca - alginate 겔 입자가 첨가된 Airlift 반응기에서 산소의 물질전달에 관한 연구

이근후,도동섭 ( Keun Hoo Lee,Dong Sup Doh ) 한국화학공학회 1993 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.31 No.4

To investigate the performance of external-loop airlift reactors, the gas holdup and the volumatric mass transfer coefficient were determined experimentally in an airlift reactor with Ca-alginate gel beads. The results show that the overall gas holdup and liquid-phase mass transfer coefficient increased with increasing gas velocity but slightly decreased with increasing particle concentration. The particle size had no clear effect on the variation of gas holdup or oxygen transfer. A mass transfer model was proposed based on Higbie`s penetration theory and Kolmogoroffs isotropic turbulence theory, and it compared fairly with experimental data.

暴雨의 時間的 分布에 關한 硏究

이근후,Lee, Keun-Hoo 한국농공학회 1984 한국농공학회논문집 Vol.26 No.2

This study was carried out to investigate the time distribution of single storms and to establish the model of storm patterns in korea. Rainfall recording charts collected from 42 metheorological stations covering the Korean peninsula were analyzed. A single storm was defined as a rain period seperated from preceding and succeeding rainfall by 6 hours and more. Among the defined single storms, 1199 storms exceeding total rainfall of 80 mm were qualified for the study. Storm patterns were cklassified by quartile classification method and the relationship between cummulative percent of rainfalls and cummulative storm time was established for each quartile storm group. Time distribution models for each stations were prepared through the various analytical and inferential procedures. Obtained results are summarized as follows: 1. The percentile frequency of quartile storms for the first to the fourth quartile were 22.0%, 26.5%, 28.9% and 22.6%, respectively. The large variation of percentile frequency was show between the same quartile storms. The advanced type storm pattern was predominant in the west coastal type storm patterns predominantly when compared to the single storms with small total rainfalls. 3. The single storms with long storm durations tended to show delayed type storm patterns predominantly when compared to the single storms with short storm durations. 4. The percentile time distribution of quartile storms for 42 rin gaging stations was estimated. Large variations were observed between the percentiles of time distributions of different stations. 5. No significant differences were generally found between the time distribution of rainfalls with greater total rainfall and with less total rainfall. This fact suggests that the size of the total rainfall of single storms was not the main factor affecting the time distribution of heavy storms. 6. Also, no significant difference were found between the time distribution of rainfalls with long duration and with short duration. The fact indicates that the storm duration was no the main factor affecting the time distribution of heavy storms. 7. In Korea, among all single storms, 39.0% show 80 to 100mm of total rainfall which stands for the mode of the frequency distribution of total rainfalls. The median value of rainfalls for all single storms from the 42 stations was 108mm. The shape of the frequency distribution of total rainfalls showed right skewed features. No significant differences were shown in the shape of distribution histograms for total rainfall of quartile storms. The mode of rainfalls for the advanced type quartile storms was 80~100mm and their frequencies were 39~43% for respective quartiles. For the delayed type quartile storms, the mode was 80~100mm and their frequencies were 36!38%. 8. In Korea, 29% of all single storms show 720 to 1080 minutes of storm durations which was the highest frequency in the frequency distribution of storm durations. The median of the storm duration for all single storms form 42 stations was 1026 minutes. The shape of the frequency distribution was right skewed feature. For the advanced type storms, the higher frequency of occurrence was shown by the single storms with short durations, whereas for the delayed type quartile storms, the higher frequency was shown gy the long duration single storms. 9. The total rainfall of single storms was positively correlated to storm durations in all the stations throughout the nation. This fact was also true for most of the quartile storms. 10. The third order polynomial regression models were established for estimating the time distribution of quartile storms at different stations. The model test by relative error method resulted good agreements between estimated and observed values with the relative error of less than 0.10 in average.

양수장 용수공급 논 지대의 물수지

이근후,정운태,이인영,Lee Keun-hoo,Cheong Un-tae,Lee In-young 한국관개배수위원회 1999 한국관개배수논문집 Vol.6 No.2

To investigate the water balance in a paddy field with the pumping station, flow measurements and analysis on various components of water balance were carried out. The investigated area was 103.69ha, and irrigation water was supplied for 102 days of the e

온실 재배 풋고추의 필요수량

이근후,윤용철,서원명,Lee Keun Hoo,Yoon Yong Cheol,Suh Won Myung 한국관개배수위원회 2000 한국관개배수논문집 Vol.7 No.2

This study was carried out to investigate the water requirement of green peppers which are cultivated in a greenhouse under the different soil water conditions. The meteorological conditions during the experiment period was not predominantly different fro

월강우량(月降雨量)의 모의발생(模擬發生)에 관(關)한 연구(硏究)

이근후 ( Keun Hoo Lee ),류한열 ( Han Yeol Ryu ) 한국농공학회 1976 韓國農工學會誌 : 전원과 자원 Vol.18 No.4

This study was carried out to clarify the stochastic characteristics of monthly rainfalls and to select a proper model for generating the sequential monthly rainfall amounts. The results abtained are as follows: 1. Log-Normal distribution function is the best fit theoretical distribution function to the empirical distribution of monthly rainfall amounts. 2. Seasonal and random components are found to exist in the time series of monthly rainfall amounts and non-stationarity is shown from the correlograms. 3. The Monte Carlo model shows a tendency to underestimate the mean values and standard deviations of monthly rainfall amounts. 4. The 1st order Markov model reproduces means, standard deviations, and coefficient of skewness with an error of ten percent or less. 5. A correlogram derived from the data generated by 1st order Markov model shows the charaterstics of historical data exactly. 6. It is concluded that the 1st order Markov model is superior to the Monte Carlo model in their reproducing ability of stochastic properties of monthly rainfall amounts.

강우기록년한(降雨記錄年限)이 확률수문량(確率水文量) 추정(推定)에 미치는 영향에 관한 연구

이근후 ( Keun Hoo Lee ),한욱동 ( Wook Dong Han ) 한국농공학회 1981 韓國農工學會誌 : 전원과 자원 Vol.23 No.2

Long term precipitation gaging station record (58 years) was analyzed by progressive mean method to compare the estimated effective period of records for computing mean and probable values. Obtained results are as follows: 1. Fifty-eight years precipitation records at Jinju, Gyeong Sang Nam Do was analyzed by double mass analysis method. Result was appeared that the record was consistent with time. 2. The effective period of records for estimating mean values with the departure of 5% or less from the true mean are up to 33 years for annual precipitation, 20 years for annual maximum daily precipitation and 45 years for maximum successive dry days in summer season. 3. To estimate the probable values by Gumbel-Chow method within the departure of 5% level from true value, periods of 51 years, 38 years and 45 years were required for annual precipitation, annual maximum daily precipitation and maximum successive dry days in summer season, respectively.

온실재배 풋고추의 소비수량

이근후 ( Lee Keun Hoo ),이종창 ( Lee Jong Chang ),윤용철 ( Yoon Yong Cheol ),서원명 ( Suh Won Myung ) 한국농공학회 2000 한국농공학회 학술대회초록집 Vol.2000 No.-

This study was carried out to investigate the water requirement of green peppers which are cultivated in a greenhouse under the different soil water conditions. The meteorological conditions during the experiment period was not predominantly different from the conditions in a normal year. The highest leaf area per plant, plant height, and yield were 6,143㎠/plant, 107cm, and 751g/plant, respectively. And daily variation of water requirements of green peppers ranged from 30 to 1,250g/d/plant which was fluctuated with significant difference. Total water requirements per plant which cultivated under the soil water conditions with different saturation ratios were 23,619g for P100, 43,044 for P80, and 2915g for P60, respectively. There were close correlation between plant height and water requirements. Low correlations were found between greenhouse ambient temperature and water requirement, while significant linear regression was shown between both of humidity and solar radiation and water requirement.

논 지역 시설재배지에서의 유기물 및 영양염류 유출 특성

이근후 ( Lee Keun-hoo ),옥정훈 ( Ok Jeong-hoon ),유시창 ( Ryu Si-chang ),유찬 ( Yu Chan ) 한국농공학회 2005 한국농공학회 학술대회초록집 Vol.2005 No.-

Runoff characteristics of organic matters and nutrients from greenhouse site in paddy field area were investigated during the irrigation period in 2004. The greenhouse selected which situated near the Nam river, Jinju, Korea used the ground water as the irrigation purpose. And, the rotating system of paddy field to upland was adapted as a cropping system which is a typical practice in this area. Various items such as total phosphorus(T-P), total nitrogen(T-N), dissolved oxygen(DO), BOD, etc. were observed to figure out the seasonal and spatial variation in the study sites. it was found that the risk of water pollution due to the contamination of nutrients in canals in green house sites, and their neighbouring small sized streams are much higher than those in ordinary paddy field areas. Further surveys and investigations are required to find out the counter measures to reduce water pollution occurred in greenhouse sites.

차세대 화학기술 포럼 새로운 에너지 수소제조 - 연료개질 시스템

이근후 ( Keun Hoo Lee ) 한국공업화학회 2004 공업화학전망 Vol.7 No.5

한국(韓國) 일강우(日降雨)의 추계학적(推計學的) 구조(構造)

이근후 ( Lee Keun Hoo ) 한국농공학회 1989 韓國農工學會誌 : 전원과 자원 Vol.31 No.4

Various analyses were made to investigate the stochastic structure of the daily rainfall in Korea. Records of daily rainfall amounts from 1951 to 1984 at Chinju Metesrological Station were used for this study. Obtained results are as follows : 1. Time series of the daily rainfall at Chinju were positively, serially correlated for the lag as large as one day. 2. Rainfall events, defined as a sequence of consecutive wet days separated by one or more dry days, showed a seasonal variation in the occurrence frequency. 3. The marginal distribution of event characteristics of each month showed significant differences each other. Events occurred in summer had longer duration and higher magnitude with higher intensity than those of events occurred in winter. 4. There were significant positive correlations among four event characteristics ; duration, magnitude, average intensity, and maximum intensity. 5. Correlations among the daily rainfall amounts within an event were not significant in general. 6. There were no consistant significancy in identity or difference between the distributions of daily rainfall amounts for different days within events. 7. Above mentioned characteristics of daily rainfall time series must be considered in building a stochastic model of daily rainfall.