'학자적 교원' 모형의 개발과 적용

홍성창 한국교원교육학회 2012 한국교원교육연구 Vol.29 No.1

본 연구는 교원들의 지속적 전문성 신장의 노력을 유도하고, 동시에 교직의 위기를 해결하고 위해 새로운 교원 정책의 일관된 틀을 구안하였다. 학문(scholarship)과 학자(scholar)의 특성, 교직 사회의 구성요소 등을 연계하여 '학자적 교원(teacher as scholar)' 모형을 제시하였다. 이는 학자적 전문성(연구, 통합, 적용, 교육), 교원 발달 단계(준비, 입문, 성장, 안정), 경력경로(교수직, 학교경영직, 장학직), 그리고 평가 및 보상 체계(교원 평가, 성과급제, 근무평정 등) 등 네 가지의 요소로 구성되어 있다. 교원 정책의 일관된 틀은 교원의 전문성 개발과 경력경로 개발을 위한 구조를 수립하는데 도움이 될 것이며, 교원정책의 기획과 개발과정에서도 정책의 목표와 지향점을 보다 체계적으로 마련하는데 활용될 수 있을 것이다.

유동층연소로에서 압력요동특성치를 이용한 균일입자계 유 무연탄 혼합연소특성 해석

홍성창,차왕석,도동섭,장현태 한국화학공학회 1999 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.37 No.4

내경 0.155m, 높이 2.2m의 유동층연소로에서 유연탄과 무연탄의 혼합연소특성실험을 수행하였다. 본 실험에 사용된 무연탄은 발열량 2,020㎉/㎏으로 저품위 고회분 무연탄이며, 유연탄은 호주산으로 발열량이 6,520㎉/㎏인 저회분 고품위이다. 유동층연소로에서 연소특성을 해석하기 위하여 균일입자의 무연탄과 유연탄을 대상으로 무연탄 혼합비, 석탄 입경비 등을 변수로 실험을 수행하여 압력요동특성치 및 물리화학적 특성치를 이용하여 연소특성을 해석하였다. 유동층연소로에서 혼합석탄의 연소특성 해석은 압력요동특성치의 압력요동의 표준편차, 평균압력, power spectrum density function을 이용하였으며, 압력요동특성치로부터 유동층연소로에서 각각 석탄의 연소영역을 측정할 수 있었다. The characteristics of mixed-firing of an anthracite and a bituminous coal were studied in a fluidized bed combustor(0.155 m-I.D., 2.2 m-height). The used domestic anthracite coal has heating value of 2,010 ㎉/㎏ and the imported high-calorific bituminous coal has heating value of 6,520 ㎉/㎏. The physicochemical analysis and the pressure fluctuation properties were measured to interpret the combustion characteristics in a fluidized bed combustor of uniform particles of mixed anthracite and bituminous coal is a function of the particle size ratio and the anthracite mixing fraction. The combustion characteristics of mixed fuels in a fluidized bed combustor could be interpreted by using standard deviation of pressure fluctuations, mean pressure and power spectrum density function. The different burning region of fluidized bed combustor was measured by the pressure fluctuation properties.

신개발 심층시비장치를 이용한 심층시비의 밭작물 재배 효과

홍성창,김민욱,김진호,박성직 한국환경농학회 2023 한국환경농학회지 Vol.42 No.1

Nitrogen fertilizers applied to agricultural lands for crop cultivation can be volatilized as ammonia. The released ammonia can catalyze the formation of ultrafine dust (particulate matter, PM2.5), classified as a short-lived cli-mate change pollutant, in the atmosphere. Currently, one of the prominent methods for fertilizer application in agri-cultural lands is soil surface application, which comprises spraying the fertilizers onto the soil surface, followed by mixing the fertilizers with the soil. Owing to the low nitro-gen absorption rate of crops, when nitrogen fertilizers are applied in this manner, they can be lost from land surfaces through volatilization. Therefore, investigating a new fer-tilization method to reduce ammonia emissions and in-crease the fertilizer utilization efficiency of crops is nece- ssary. In this study, to develop a method for reducing am-monia emissions from nitrogen fertilizers applied to soil surfaces, deep fertilization was conducted using a newly developed deep fertilization device, and ammonia emis-sions from barley, garlic, and onion fields were examined. Conventional fertilization (surface application) and deep fertilization (soil depth of 25 cm) were conducted for analysis. The fertilization rate was 100% of the standard fertilization rate used for barley, and deep fertilization of N, P, and K fertilizers was implemented. Ammonia emis-sions were collected using a wind tunnel chamber, and quantified subsequently susing the indole-phenol blue method. Ammonia emissions released from the basal fer-tilizer application persisted for approximately 58 d, begin-ning from approximately 3 d after fertilization in conven-tional treatments; however, ammonia was not released from deep fertilization. Moreover, barley, garlic, and on-ion yields were higher in the deep fertilization treatment than in the conventional fertilization treatment. In con-clusion, a new fertilization method was identified as an al-ternative to the current approach of spraying fertilizers on the soil surface. This new method, which involves inject-ing nitrogen fertilizers at a soil depth of 25 cm, has the po-tential to reduce ammonia emissions and increase the yields of barley, garlic, and onion. .

신개발 심층시비장치를 이용한 심층시비가 벼와 콩 수량에 미치는 영향

홍성창,김민욱,김진호 한국환경농학회 2023 한국환경농학회지 Vol.42 No.1

Nitrogen fertilizer is an essential macronutrient that re-quires repeated input for crop cultivation. Excessive use of nitrogen fertilizers can adversely affect the environ-ment by discharging NH3, NO, and N2O into the air and leaching into surrounding water systems through rainfall runoff. Therefore, it is necessary to develop a technology that reduces the amount of nitrogen fertilizer used without compromising crop yields. Fertilizer deep placement could be a technology employed to increase the efficiency of ni-trogen fertilizer use. In this study, a deep fertilization de-vice that can be coupled to a tractor and used to inject fer-tilizer into the soil was developed. The deep fertilization device consisted of a tractor attachment part, fertilizer amount control and supply part, and an underground fer-tilizer input part. The fertilization depth was designed to be adjustable from the soil surface down to a depth of 40 cm in the soil. This device injected fertilizer at a speed of 2,000 m2/hr to a depth of 25 to 30 cm through an under-ground fertilizer injection pipe while being attached to and towed by a 62-horsepower agricultural tractor. Furthermore, it had no difficulty in employing various fertil-izers currently utilized in agricultural fields, and it oper-ated well. It could also perform fertilization and plowing work, thereby further simplifying agricultural labor. In this study, a newly developed device was used to inves-tigate the effects of deep fertilizer placement (FDP) com-pared to those with urea surface broadcasting, in terms of rice and soybean grain yields. FDP increased the number of rice grains, resulting in an average improvement of 9% in rice yields across three regions. It also increased the number of soybean pods, resulting in an average increase of 23% in soybean yields across the three regions. The re-sults of this study suggest that the newly developed deep fertilization device can efficiently and rapidly inject fer-tilizer into the soil at depths of 25 to 30 cm. This fertilizer deep placement strategy will be an effective fertilizer ap-plication method used to increase rice and soybean yields, in addition to reducing nitrogen fertilizer use, under con-ventional rice and soybean cultivation conditions. .

압력요동을 이용한 밀도가 다른 이성분 혼합입자계의 최소유동화속도 측정

홍성창,도동섭,장현태 한국화학공학회 1995 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.33 No.3

내경 0.109 m의 유동층에서 밀도차가 있는 모래와 PMMA의 혼합계에 대한 압력요동의 표준편차와 유속간의 선형회귀분석을 이용한 최소유동화속도 측정법의 적용성을 조사하였다. 이성분계 혼합물의 압력요동의 표준편차를 이용한 최소유동화속도를 flotsam의 분율과 입자크기에 따라 측정하고, 측정치를 타 연구자들의 이성분계식과 비교 검토하였다. 압력요동 표준편차 값의 선형회귀분석으로부터 최소유동화속도 결정에서 유속의 범위는 혼합도가 낮은 유속범위와 free bubbling 영역 이상을 제외한 범위 값이어야 하며, 이 유속범위에서 측정위치는 혼합이 양호한 층 중앙이 가장 적절하다. The determination method of minimum fluidization velocity from the linear regression of standard deviation of pressure fluctuation according to air velocity was investigated with binary mixture of sand and PMMA in a 0.109 m I.D. fluidized bed. The experiments were performed with change of operating variables such as the fraction of flotsam and particle size, and the measured values of the minimum fluidization velocity were compared with those obtained by the other researchers. The air velocity for this method has limited from well mixed region to freely bubbling region in a fluidized bed. The optimal measuring height of pressure fluctuations seems to be at middle levels on the axis of a bed, where the solid is well mixed.

크기가 다른 두 입자계의 초소유동화속도 결정 및 유동화 특성

홍성창,차왕석,도동섭,오광중 한국화학공학회 1992 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.30 No.6

내경이 0.109m인 기-고유동층에서 큰 입자(0.175 ㎜)로 이루어진 계에 크기가 작은 입자(0.359 ㎜, 0.194 ㎜)의 분율을 변화시킴에 따라 나타나는 층분리 현상을 차압전달기로 측정하여 압력요동의 평균압력과 표준 편차를 이용하여 분석하였다. 크기가 작은 입자의 분율에 따른 최소유동화속도 변화를 규명하였고, 또한 층내에서 일어나는 기포의 운동과 입자혼합을 표준편차로서 해석하였다. 실험결과 균일입자로 이루어진 계에서만 적용되었던 압력요동의 표준편차와 유속과의 관계로부터 최소유동화속도를 결정하는 방법은 크기가 다른 두 입자계까지 적용될 수 있음을 알 수 있었으며, 입자크기 차이에 의한 층분리 현상을 압력요동으로 예측할 수 있다. Segregation phenomena occurred from variations of fine particle fractions(0.359 ㎜, 0.194 ㎜) in a 0.109 m ID fluidized bed of coarse particle(0.715 ㎜) were measured by a differential pressure transducer and were analyzed by the standard deviation and mean pressure of pressure fluctuations. The variations of minimum fluidization velocity according to fine particle fractions were investigated and the fluidized bed behaviors such as bubble motion and particle mixing were interpreted by the standard deviation. The method for determination of a minimum fluidization velocity from the linear relationship between standard deviation and air velocity which has been applied only for the uniform sized particle system could also be applied in the binary system. Segregation phenomena occurred by the difference of particle size could also be predicted by the pressure fluctuations.

유동층반응기에서 MeO/NMD를 이용한 저농도 연소가능 오염물의 제거

홍성창,도동섭,박태성,정순관,윤재성 한국화학공학회 1998 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.36 No.5

저농도의 연소가능한 유기화합물을 제거하기 위하여 천연망간광석(NMD: Natural Manganese dioxide)을 기본으로 하여 Pt, Pd를 담지시킨 촉매를 사용하여 CH₄, C_6H_6, C₂H_5OH, CO의 산화반응을 유동층반응기에서 여러 변수에 대해 실험을 수행하였다. 동일한 유속에서 입자크기의 영향은 0.359㎜의 경우가 좋은 효율을 보였으며 층내 기포분율과 반응물의 체류시간의 영향으로 유속이 작고 종횡비가 클수록 산화반응이 우수하였다. 또한 귀금속촉매를 NMD에 담지시킨 경우는 담지시키지 않은 경우보다 낮은 온도에서 유기화합물을 산회시켰고 메탄에 대해서는 PdO/NMD의 경우 실험온도가 Pd의 구조적인 변화를 일으키는 온도이상이므로 NMD보다 산화능력이 떨어졌다. For the removal of combustible pollutant gas at low concentration, the experiment about oxidation of CH₄, C_6H_6, C₂H_5OH, CO, was carried out using platinum, paladium-impregnated NMD(Natural Manganese Dioxide) in the fluidized bed reactor for several variables. At the same flow velocity the effect of particle size on conversion appeared most efficient in the size of 0.359 ㎜. The oxidation was excellent at low flow velocity and large aspect ratio because of the effect of residence time of reactant. Also the, noble metal-impregnated catalyst oxidated VOCs at more low temperature than catalyst without impregnation. For methane oxidation ability of PdO/NMD decreased in the reason that experimental temperature was so high that the structural transformation was caused.

잎들깨 수량과 단백질체 발현에 미치는 UV-B의 영향

홍성창,황선웅,장안철,신평균,장병춘,이철원 한국환경농학회 2006 한국환경농학회지 Vol.25 No.1

An analysis of the relationship between self-study, private tutoring, and self-efficacy on self-regulated learning

홍성창,박윤수 한국교육개발원 2012 KEDI Journal of Educational Policy Vol.9 No.1

This study examines the effect of study behavior that includes self-study and private tutoring; motivation characterized by self-esteem, self-efficacy, and test anxiety; and parental support on self-regulated learning using cross-sectional and longitudinal methods. These relationships were investigated using the Korean Education Longitudinal Study 2005 (KELS, 2005) data, restricting major analyses to students attending general high schools. Results showed that the effect of private tutoring on self-regulated learning was negative, while self-study showed a positive effect. Furthermore, self-study hours seemed to moderate the effect of self-efficacy on self-regulated learning; students that had higher levels of self-study hours also had greater levels of self-regulated learning, whereas students with lower self-study hours had lower levels of self-regulated learning. Results from cross-sectional structural equation models showed that the direct effects of self-esteem and self-efficacy had a significant effect on self-regulated learning. Using a longitudinal analysis based on multilevel random effects regression, the effects of self-esteem and self-efficacy on self-regulated learning were .28 and .17 standardized units, respectively. Test stress also had a minimal yet significant effect of .04 points. The findings from this study show that rather than focusing on private tutoring, efforts to improve self-study, self-esteem, and self-efficacy can lead to an increase in students’ behaviors of self-regulated learning.

배가스 중 SO₂가 V/TiO₂ SCR활성에 미치는 영향

홍성창,Hong, Sung-Chang 한국공업화학회 2006 공업화학 Vol.17 No.5

$V_{2}O_{5}$/$TiO_{2}$계 선택적촉매환원법(SCR) 촉매는 $SO_{2}$가 존재하는 조건에서 $SO_{2}$의 산화 및 암모니아의 반응에 의해 형성된 황산암모늄염으로 인해 촉매는 비활성화될 수 있다. 본 연구에 의하면, $SO_{2}$에 의한 촉매의 비활성화는 $SO_{2}$의 흡착이후 $SO_{3}$로의 산화 정도에 의존한다. $SO_{2}$의 산화는 배가스 내의 산소 농도에 약하게 영향을 받으며 바나듐 함량에 영향을 받는다. 또한 미반응 암모니아 역시 황산암모늄염 형성의 원인이므로 SCR 반응에 있어서 암모니아 투입비율에 대한 영향을 도출하였다. 황산암모늄염에 의해 비활성화된 촉매가 낮은 SCR 활성을 갖는 이유를 촉매의 기공부피 변화에서 찾을 수 있다. 이러한 황산암모늄염의 분해 반응도출을 위해 TPD (Temperature Programmed Decomposition) 실험이 수행되었다. $V_{2}O_{5}$/$TiO_{2}$ catalyst can be deactivated by ammonium salts formed by $SO_{2}$ oxidation and unreacted ammonium in presence of $SO_{2}$ in flue gas. The deactivation of catalyst by $SO_{2}$ depends on the $SO_{2}$ oxidation to $SO_{3}$. The oxidation of $SO_{2}$ is weakly affected by oxygen concentration, and strongly by the amount of vanadium loaded onto titania supports. Because unreacted ammonia is one of elements to form the ammonium salts, it is important to control the mole ratio of $NH_{3}/NOx$ in SCR. Thus the experiments about $NH_{3}/NOx$ were carried out. The reason of low activity of catalyst deactivated by ammonium salts is the change of pore volume. And TPD (Temperature Programmed Decomposition) was performed to find the decomposition of ammonium bisulfate on deactivated catalyst.