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입경분포가 있는 정상상태 유동층으로부터의 입자의 선별 유출
김희영,윤풍,전종열,송영목 한국화학공학회 1988 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.26 No.4
입자가 성장하는 연속 정상상태 유동층 반응기에서의 입자 유동을 상온에서 모사할 수 있는 반응부 유동층의 하부에 큰 제품입자를 선별 유출할 수 있는 분리관을 설치하여 입경분포를 갖는 반응부 유동층 입자들의 분리를 연구하였다. 이 분리관을 통해 정상상태 반응부 유동층내에서 큰 입자들을 선택적으로 계속 유출하기 위해 혼합입자의 최대 및 최소 입자에 대한 초기 유동속도의 범위내에서 분리관 내부의 유동상태를 유지시켰다. 이러한 분리관을 이용하여 반응부 유동층에서의 유동조건에 영향을 미치지 않고 높은 입자 분리 효과를 거둘 수 있었는데, 이를 위해서는 반응부 유동층의 평균입경 및 분포의 특성과 분리관에서의 유동 특성에 대해 제한적인 조업범위가 존재함이 나타났다. 이러한 허용 조업범위하에서의 실험결과를 토대로 주어진 구조에 대해 반응부 유동총의 입경분포와 선별 유출된 입자들의 입경분포와의 관계식을 조업특성 변수들과 입경외 함수로 표시하여 실험 값들을 정량적으로 설명할 수 있음을 밝혔다. Continuous segregation of particles with size distribution was studied in a particle withdrawal boot attached to the bottom of a fluidized bed which was installed to simulate the particle dynamics in a particle growing reactor. In order to withdraw continuously and preferentially large particles in steady state from the main fluidized bed the boot was mildly fluidized between the incipient fluidization velocities of the largest and smallest size fractions. It was observed that a high degree of segregation can be achieved in the limited range of the fluidization condition at the boot as well as of the particle size and distribution mode at the main fluidized bed. In the acceptable operation range the segregation efficiency of large particles could fairly well be related to those operational parameters for a given boot geometry, and the empirical relationship proposed in this study were in good agreement with experimental observations.
김희영,김경한 현대영어교육학회 2017 현대영어교육 Vol.18 No.1
The goal of this study is to develop and apply an English instructional model using poetic language with rhythmic patterns. Poetic language as learning materials in the EFL classroom has repetitive rhythms, which make patterns. These rhythmic patterns are known to be helpful for memory, contributing to language acquisition. In this study, the instructional model was applied to the students of two classes in S middle school for 10 periods. The experimental group was given an instructional model that deals with poetic materials in the textbook, whereas the control group was given a traditional method that treats the same materials in the textbook. The poetic materials were found in the sources like nursery rhymes, children’s poems and songs, etc. The students’ cognitive and affective ability was measured by a diagnostic test for English and an affective test developed by the researchers. The test result was analyzed by the independent samples t-test. As a result, it showed that the students that used the poetic model improved in both the cognitive and affective domain. Likewise, the data from class observation sheets and students’ after-class response sheets showed a positive result. The study proves that the instructional model, which focuses on learning with poetic language with rhythmic patterns, is efficient in developing middle-school students’ English ability.
김희영,박예진,이주연,김기영,신수,최민우,홍은진,김민정,여수정,박인화,정의민,안효진,차윤엽 대한본초학회 2022 大韓本草學會誌 Vol.37 No.5
Objectives : This research was performed to analyze the components in the different parts of Lythrum salicaria L. and to compare which parts of L. salicaria L. are appropriate for food development. Methods : L. salicaria L. was extracted in 20% EtOH at 100 ℃ for 4 hours. Cytotoxicity was investigated in 3T3-L1 cells after treatment of 10-500 μg/ml L. salicaria L. for 24 hours. Total polyphenol content (TPC) was estimated using 1 N Folin-ciocateu reagent. 2,2-Diphenyl-1-picryhydrazyl (DPPH) radical scavenging activity was estimated using DPPH reagent and gallic acid. The chemical composition was analyzed by high-performance liquid chromatography (HPLC). 1) Results : The half maximal inhibitory concentration (IC50) in the extracts of the whole plant, aerial parts, and root parts was 350 μg/ml, over 500 μg/ml, and 150 μg/ml, respectively. The TPC in the extracts of the whole plant, aerial parts, and root parts was 527.1 mg/g, 422.6 mg/g, and 781.1 mg/g, respectively. The averages of vitexin contents in the aerial parts, and root parts were 256.7 ± 154.9 μg/g and 266.1 ± 63.2 μg/g, respectively. The averages of TPC in the leaves, roots, flower stalks and stems were 224.0 ± 53.7 tannin acid (TA) mg/g, 221.8 ± 70.2 TA mg/g, 249.8 ± 34.4 TA mg/g, and 67.7±8.9 TA mg/g, respectively. The averages of DPPH radical scavenging activity in the leaves, roots, flower stalks, and stems were 282.01 ± 43.3 gallic acid equivalent (GAE) μmole/g, 260.16 ± 44.1 GAE μmole/g, 288.0 ± 9.3 GAE μmole/g, and 97.6 ± 10.7 GAE μmole/g, respectively. Conclusions : There were no significant differences in the content of components or antioxidant activity in the aerial parts compared to those in the whole plant of L. salicaria L. Furthermore, the root parts had low extract yield, cytotoxicity, and quality control problems, therefore our results suggest that the use of the aerial part of L. salicaria L. would be the most appropriate for food development.