코발트계 페라이트 분말을 이용한 이산화탄소 전환특성

박성열 ( Sung Youl Park ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.6

The amount of domestic carbon dioxide emissions is more than 600 million tons/year. The emitted CO2 should be captured and stored, however, suitable storage sites have not been found yet. A lot of researches on the conversion of captured carbon dioxide to useful carbon source have been conducted. The purpose of this study is to convert stable carbon dioxide to useful resources using less energy. For this purpose reducing gas and metallic oxide (activator) are required. Hydrogen was used as reducing gas and cobalt ferrite was used as activator. Considering that activator has different physical properties depending on synthesis methods, activator was prepared by hydrothermal synthesis and solid method. Decomposition characteristics of carbon dioxide were investigated using synthesized powders. Temperature programmed reduction/oxidation (TPR/TPO) and thermogravimetric analyzer (TGA) device were used to observe the decomposition characteristics of carbon dioxide. Activator prepared by solid method with 5 and 10 wt% CoO content showed an excellent performance. In TGA experiments with samples prepared by the solid method, reduction by hydrogen was 29.0 wt% and oxidation by CO2 was highest in 27.5 wt%. 95% of adsorbed CO2 was decomposed with excellent oxidation-reduction behaviors.

중요부하를 갖는 하이브리드 ESS의 무효전력 변동에 의한 단독운전방지 기법

박성열(Sung-Youl Park),권민호(Min-Ho Kwon),최세완(Se-Wan Choi) 전력전자학회 2015 전력전자학술대회 논문집 Vol.2015 No.11

기술수용모델(TAM)을 이용한 농업교육프로그램 참여의향도 분석과 향상 방안

박성열 ( Sung-youl Park ),최승철 ( Seung-churl Choi ),차승봉 ( Seung-bong Cha ),김재선 ( Jae-seon Kim ),송민영 ( Min-young Song ) 한국농업정책학회 2011 농업경영정책연구 Vol.38 No.3

The purposes of the study were to determine the relationships among the factors that affect farmers participation intention in agricultural education programs and to propose implications for improvement based on the technology acceptance model. Also, determined were some descriptive characteristics of the selected factors. The study sample was 219. For descriptive statistics such as frequencies, means and correlation coefficient, SAS version 9.1 was used. In addition, LISREL version 8.30 was employed for statistical analyses of the structural equation models. The general structural equation model based on TAM included perceived usefulness, perceived ease of use, attitude, and participation intention as endogenous variables and accessibility, self-efficacy and social norm as exogenous variables. The study results confirmed the acceptability of the model to understand farmers` participation intention in agricultural education programs. Attitude, perceived ease of use, and self-efficacy were identified having direct effect on participation intention in agricultural programs. In terms of the magnitude of the parameter estimates, attitude was the most significant factor related to participation intention. It was revealed that accessibility had not direct and indirect effect on any endogenous variables.

이산화탄소 흡수 공정에서 흡수액 최적 재생 조건에 대한 이론적 고찰

박성열 ( Sung Youl Park ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.6

The considerable portion of energy demand has been satisfied by the combustion of fossil fuel and the consequent CO2 emission was considered as a main cause of global warming. As a technology option for CO2 emission mitigation, absorption process has been used in CO2 capture from large scale emission sources. To set up optimal operating parameters in CO2 absorption and solvent regeneration units are important for the better performance of the whole CO2 absorption plant. Optimal operating parameters are usually selected through a lot of actual operation data. However theoretical approach are also useful because the arbitrary change of process parameters often limited for the stability of process operation, In this paper, a theoretical approach based on vapor-liquid equilibrium was proposed to estimate optimal operating conditions of CO2 absorption process. Two CO2 absorption processes using 12 wt% aqueous NH3 solution and 20 wt% aqueous MEA solution were investigated in this theoretical estimation of optimal operating conditions. The results showed that CO2 loading of rich absorbent should be kept below 0.4 in case of 12 wt% aqueous NH3 solution for CO2 absorption but there was no limitation of CO2 loading in case of 20 wt% aqueous MEA solution for CO2 absorption. The optimal regeneration temperature was determined by theoretical approach based on CO2 loadings of rich and lean absorbent, which determined to satisfy the amount of absorbed CO2. The amount of heating medium at optimal regeneration temperature is also determined to meet the difference of CO2 loading between rich and lean absorbent. It could be confirmed that the theoretical approach, which accurately estimate the optimal regeneration conditions of lab scale CO2 absorption using 12 wt% aqueous NH3 solution could estimate those of 20 wt% aqueous MEA solution and could be used for the design and operation of CO2 absorption process using chemical absorbent.

농업인 ICT리터러시 향상을 위한 정보화 교육 개선 방안

박성열 ( Sung Youl Park ),최승철 ( Seung Churl Choi ),차승봉 ( Seung Bong Cha ),김학섭 ( Hak Seob Kim ),임종훈 ( Jong Hun Lim ) 한국농업정책학회, 한국축산경영학회 2009 농업경영정책연구 Vol.36 No.4

마이크로그리드에서 에너지 저장시스템을 위한 무순단 절체 기능을 갖는 계통연계형 인버터의 병렬운전 제어기법

박성열(Sung-Youl Park),김주하(Joo-Ha Kim),정아진(Ah-Jin Jung),최세완(Se-Wan Choi) 전력전자학회 2016 전력전자학회 논문지 Vol.21 No.3

정보기술수용모델을 적용한 대학생 모바일러닝 사용의도와 영향요인 간 구조적 관계 분석

박성열 ( Sung Youl Park ),남민우 ( Min Woo Nam ) 한국교육정보미디어학회(구 한국교육정보방송학회) 2012 교육정보미디어연구 Vol.18 No.1

이 연구는 정보기술수용모델(TAM) 관점에서 대학생들의 모바일러닝 사용의도에 영향을 미치는 요인들과 요인들간의 구조적 관계성 규명을 목적으로 하였다. 이 연구를 위하여 모바일러닝 사용의도에 영향을 미치는 내생변인으로 모바일러닝 태도, 모바일러닝 유용성, 모바일러닝 사용용이성 등을 설정하였고, 자아효능감, 학업관련성, 시스템 접근성, 주관적 규범 등을 외생변인으로 하는 연구 모델을 설정하였다. 서울소재 K대학의 대학생 648명을 대상으로 설문자료를 수집하였으며, 연구 모델에 포함된 요인들의 상관관계 매트릭스를 LISREL에 삽입하여 구조방정식 모델 분석을 수행하였다. 이 연구의 주요연구결과를 요약하면 다음과 같다. 첫째, 이 연구에서 제시된 구조방정식 모델의 전반적 적합도 검증결과는 RMR=.041, RMSEA=.064, GFI=.894, AGFI=.865, NFI=.926, CFI=.945 CN=223.40 등으로 분석되어 모델의 적합도는 양호하였다. 둘째, 구조방정식 모델에서 관계성을 분석한 결과 대학생들의 모바일러닝 사용의도에 대하여 모바일러닝 태도, 학업관련성, 주관적 규범이 유의한 영향을 미치는 것으로 나타났다. 모바일러닝 태도에는 지각된 유용성과 자아효능감, 학업관련성, 주관적 규범이, 모바일러닝의 지각된 유용성에는 지각된 사용용이성, 학업관련성, 주관적 규범이, 지각된 사용용이성에는 자아효능감과 시스템 접근성에서 유의미한 직접효과가 있는 것으로 분석되었다. 셋째, 모델의 변인 간 직접·간접효과와 경로 관계를 분석한 결과 모바일러닝의 학업관련성 및 주관적 규범이 모바일러닝 사용의도의 영향요인 간 관계에서 핵심변인으로 분석되었다. The study purpose was to identify what factors affect university students` adoption and use of mobile learning. A sample of 648 K university students participated in the research. In order to explain adoption process, the structural equation modeling technique was employed with the LISREL program. The general structural model based on the technology acceptance model (TAM) included behavioral intention to use mobile learning, mobile learning attitude, perceived usefulness, and perceived ease of use as endogenous variables and mobile learning self-efficacy, relevance for students` major, system accessibility, and subjective norm as exogenous variables. According to the goodness-of-fit test results(RMR=.041, RMSEA=.064, GFI= .894, AGFI=.865, NFI=.926, CFI=.945, IFI=.946, CN=223.40), the model turned out to be good enough to conduct the research. It was identified that mobile learning attitude, relevance for major, and subjective norm were significantly related to students` behavioral intention to use mobile learning. In terms of direct effect result, perceived usefulness, self-efficacy, relevance for major and subjective norm had significant relationships with mobile learning attitude. The study result also confirmed that perceived usefulness was influenced by perceived ease of use, relevance for major and subjective norm. Meanwhile, perceive ease of use was influenced by self-efficacy and system accessibility. Finally, relevance for major and subjective norm were identified as key variable through their direct and indirect effect on behavioral intention to use mobile learning.

구조방정식 모델을 이용한 농업 마이스터 대학 교육프로그램 교육효과성 연구

박성열 ( Sung-youl Park ),최승철 ( Seung-churl Choi ),차승봉 ( Seung-bong Cha ),정승화 ( Seung-hwa Jung ),김기주 ( Ki-ju Kim ) 한국농업정책학회 2012 농업경영정책연구 Vol.39 No.1

This study was designed to identify factors affecting the educational effect of Agriculture Meister College education programs with the sample of Agriculture Meister College students. The study set up a general structural model which included accessibility, self-efficacy, and social norm as exogenous variables and perceived easiness, perceived usefulness, attitude, and educational effect as endogenous variables. The result proved the model to be a good enough to understand the educational effect of Agricultural Meister Program based on the goodness fit statistical results. According to the results of parameter estimates and significance, easiness and usefulness among the endogenous variables were identified having direct effects on the educational effect, key endogenous variable. Meanwhile, only accessibility was found having direct effect on the educational effect. In addition, accessibility and self-efficacy were determined having indirect effects on the educational effect through easiness as an intervening variable. Further, self-efficacy and social norm were identified having indirect effects on the educational effect via usefulness. To sum up these results, it is suggested that easiness and usefulness are important variables compared to attitude as endogenous variables in the model.

중요부하를 갖는 ESS의 무효전력 P&O 단독운전 검출 기법

박성열(Sung-Youl Park),권민호(Min-Ho Kwon),강수한(Su-Han Kang),최세완(Se-Wan Choi) 전력전자학회 2016 전력전자학술대회 논문집 Vol.2016 No.7

메타분석을 통한 가정특성 관련변인이 학업성취에 미치는 영향

박성열 ( Sung Youl Park ),구병두 ( Byung Doo Ku ),임현걸 ( Hyun Geol Lim ) 건국대학교 교육연구소 2000 교사와 교육(구 교육논집) Vol.24 No.-

This paper was designed to synthesize quantitatively the master`s theses and doctoral dissertations focusing on effects of family background traits related variables on academic achievements in Korea. This task was accomplished by utilizing the meta-analysis technique of research integration as defined by Glass (982). Basically, meta-analysis is a statistical analysis of the summary findings of many empirical studies. Its purpose is to draw reliable and general conclusions from a large and complex body of literature on a common topic. Thus, the primary purpose of this paper was to conduct a quantitative synthesis of 96 master`s theses and doctoral dissertations focusing on the effects of academic achievements using family background traits as independent variable and academic achievement as dependent variable. Nine independent variables were chosen by means of in depth review of those previously mentioned 96 studies. The independent variables employed in this study include psychologcal environment, physical environment, family structure, public and private educational expenditures, educational process, breeding and educational method of parents, socio-economic status, parents` charateristics, and role expectation. These variables are cartegorized by two different groups according to the traits of factors in terms of family environment variable group and parent`s characteristics variable group. This study set the following questions to be answered: (1) How large are the grand average effect size of variables of family background traits proposed in this study on student`s academic achievement?; (2) How different the effect size of the two family background traits related variable groups, naimly family environment and parents charateristics variable group on student`s academic achievement?; and, (3) How different the effect size of the nine family background traits related independent variables on student`s academic achievement? In order to answer the research questions, the researcher followed the standard procedures as such locating published studies to collect primary data, analysing and cording the characteristics and outcomes of the studies, and carring out statistical procedures of mata-analysis to describe the overall and sub-variable effects. Primary source of data was decided to limit within the master`s theses and doctoral dissertations in order to achieve the reliability and validity of the study results. By using the CD-ROM titled ‘master · doctoral dissertation index’ published by National Central Library in 1995 and 1997, a total of 112 studies were located and collected. Out of 112 studies, 96 studies were selected by excluding those studies that are not possible to employ mata-analysis such as studies used qualitative research method. While classifying family background traits related variables some of studies were also excluded in this study due to failing a consensus among the five specialists participated in this process. The effect size were calculated by using two different approaches depending upon the applicability of effect size formula. One was by using mean and standard deviation of experimental group and their countpart. The other was using transformational formula suggested by Wolf(986) for the studies that have not presented descriptive statistics. The result of this study may be summarized as follows: (1) The grand average degree of effects of the academic achievement factors proposed in this study turned out to be .33. This means that if the average size of effects of the academic achievement factors of the controlled group is 50 percentile in the normal distribution, that of the experimental group becomes 62.93 percentile. As it were, the latter surpass the former by 12.94 percentile. (2) Between the two groups of academic achievement factors proposed in this study, in terms of family environment variable group and parent`s characteristics variable group, the former factors showed the higher average effect size, its average effect size being .35. Considering the grand average degree of effects size of .33, it can be suggested that those family environment related variables effects more on the student`s academic achievement compare to the variables of parents` characteristics. (3) Among the nine family background traits related independent variables on academic achievements proposed in this study, the variable of educational process showed the highest average effect size of 1.40, as followed by socio-economic status(effect size of 0.55), role expectation (effect size of 0.48), and physical environment(effect size of 0.40). The effect size of these variables turned out to be bigger that the grand average effect size of .33. This result means that these variable effects on student`s academic achievement a lot more compare to other variable proposed in this study. In fact, the effect size of those variables such as psychologcal environment(effect size of 0.27), breeding and educational method of parents(effect size of 0.27), family structure(effect size of 0.26), public and private educational expenditures(effect size of 0.26), and parents` charateristics(effect size of 0.14) turned out to be much smaller than that of previously mentioned variables. It means that the variable of psychologcal environment, breeding and educational method of parents, family structure, public and private educational expenditures, and parents` charateristics effect less on student`s academic achievement compare to the variables of educational process, socio-economic status, role expectation, and physical environment.