• Rapid Communication in Photoscience
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• 제1권2호
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• pp.41-41
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• 2012

• 한국과학교육학회지
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• 제32권10호
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• pp.1524-1536
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• 2012

과학 태도는 학습의 질 향상에 영향을 미치며 과학 교육에서 중요한 관심사 중의 하나이다. 과학 태도 수준에 따라서 인지적 영역의 구조적 측면, 특히 개념간의 근접성 분석이 필요하다. 따라서 이 연구에서는 과학 태도 수준에 따라서 광합성 관련 개념의 근접성이 수업 후에 어떻게 변하는지를 분석하는데 그 목적이 있다. 이를 위하여 7학년 학생 270명을 대상으로 수업 전과 수업 후의 과학 태도와 광합성 개념에 대한 조사를 실시하였다. 광합성 개념은 '광합성이 일어나는 장소', '광합성에 필요한 물질', '광합성결과생성 되는 물질', '광합성에 영향을 미치는 요인'으로 구성하였다. 광합성 개념의 근접성은 다차원 척도법을 활용하여 분석하였다. 이 연구 결과는 다음과 같다. (1) 수업을 통해 학생들은 구체적인 개념을 습득함으로써 개념의 근접성을 변화시키는 것으로 나타났다. (2) 학습을 통해 과학태도 상집단이 중 하집단에 비해 과학적 개념의 근접성이 가까워지는 경향이 있다. (3) 과학 태도의 모든 수준의 학생에서 비과학적 개념이 수업 후에도 계속 존재하는 것으로 나타났다. 이 비과학적 개념이 광합성과 관련된 과학적 개념 사이의 근접성을 방해하는 것으로 판단된다. (4) 학생들은 광합성과 관련된 4개 영역에서 서로 관련된 개념은 가깝게 인식하고 있는 것으로 나타났다. 학생들은 광합성에서 광합성 장소와 필요 물질을, 광합성 결과 생성되는 물질과 필요 물질을 가깝게 인식하고 있다고 할 수 있다.

• The Plant Pathology Journal
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• 제16권5호
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• pp.257-263
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• 2000

Infection with rice blast fungus (Magnaporthe grisea) significantly reduced foliar net photosynthesis (A) of rice cultivars: Ilpoom, Hwasung, and Choochung in greenhouse experiments. By measuring the amount of diseased leaf area with a computer image analysis system, the relation between disease severity (DS) and net photosynthetic rate was curvilinearly correlated (r=0.679). Diseased leaves with 35% blast symptom can be predicted to have a 50% reduction of photosynthesis. The disease severity was linearly correlated (r=0.478) with total chlorophyll (chlorophyll a and chlorophyll b) per unit leaf area(TC). Light use efficiency was reduced by the fungal infection according to the light response curves. However, dark respiration (Rd) did not change after the fungal infection (p=0.526). Since the percent of reduction in photosynthesis greatly exceeded the percent of leaf area covered by blast lesions, loss of photosynthetic tissue on an area basis could not by itself account for the reduced photosynthesis. Quantitative photosynthetic reduction can be partially explained by decreasing TC, but cannot be explained by decreasing Rd. By photosynthesis (A)-internal CO$_2$ concentration (C$_i$ curve analysis, it was suggested that the fungal infection reduced ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity, ribulose-1,5-bisphosphate (RuBP) regeneration, and inorganic phosphate regeneration. Thus, the reduction of photosynthesis by blast infection was associated with decreased TC and biochemical capacity, which comprises all carbon metabolism after CO$_2$ enters through the stomata.

• 한국과학교육학회지
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• 제29권6호
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• pp.712-729
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• 2009

본 연구에서는 고등학생들의 식물의 광합성과 호흡에 관련된 오개념을 조사하고, 이를 교정할 수 있는 방안으로 Driver 개념변화 학습 모형을 적용한 수업 프로그램을 개발 적용하여 그 효과를 알아보는데 목적이 있다. 연구 대상은 부산광역시 소재의 남자고등학교 재량교과 시간에 생물학습을 선택한 1학년 66명을 연구 대상으로 하였으며, 학생들의 광합성과 식물의 호흡에 관한 개념 정도는 그림그리기와 서술형 검사로 서로 상호적인 방법으로 조사되었다. 광합성과 식물 호흡에 관한 학생의 오개념을 단계별 수준으로 구분 짓는 방법으로 그림그리기 방법을 적용한 결과, 많은 학생들이 과학교과서나 과학자에 의해 이해되지 않은 오개념이 포함된 그림을 그렸으며, Driver 개념 변화 학습 모형 적용 후에는 식물의 광합성과 호흡의 필수 요소인 빛, 이산화탄소, 물, 포도당, 산소, 나뭇잎, 엽록체, 미토콘드리아, 기공, 에너지 등을 포함한 과학적 인 그림을 그렸다. 식물의 광합성과 호흡의 여러 측면에 대한 개념을 조사하기 위해 실시한 서술형 검사 결과에도 사전검사에서는 식물의 광합성과 호흡이 일어나는 시점과 장소, 식물의 영양소, 광합성에서의 잎의 역할, 식물의 광합성과 호흡의 관계에 대해서 많은 학생들이 오개념을 보였으나, Driver 개념변화 학습 모형을 적용한 수업 후에는 식물의 광합성과 호흡에 대한 오개념이 많이 교정된 것으로 나타났다.

• 한국자원식물학회지
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• 제7권1호
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• pp.97-101
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• 1994

The effects of NaCl salinity on the leaf photosynthesis and water relation of two cultivars of rice(Oryza sativa L.) , the salt-tolerant cultivar Seohae and the salt-senstive cultivar Iri-380 were exam-ined. Two cultivars of rice were grown for 14 days in nutrient solution at SOmM NaCl. Comparing theieaf Na content of two cultlvars, Seohae showed high accumulation of Na content in the leaf blade, while Iri-380 showed low. The Na content in leaf blade reduced the rate of leaf photosynthesis. Salt-tolerant cultivar Seohae was less decreased the rate of leaf photosynthesis than salt- sensitive cultivarIri-380. And Seohae showed larger decreased the osmotic potential in the leaves than Iri-380. This in-dicates that in the salt-tolerant cultivar, osmotic adjustment is developed under saliniEation.

• 한국과학교육학회지
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• 제33권3호
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• pp.650-663
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• 2013

Multidimensional scaling can be used to identify relationships among concepts, revealing the structure of the cognitive framework by measuring distances within perceptual maps. The current study sought to examine the relationships among concepts related to photosynthesis in 2,844 $3^{rd}-11^{th}$ grade science students. The questionnaire included items on 'location,' 'products,' 'reactants,' and 'environmental factors', presenting images related to each theme. Students provided responses corresponding to particular topics, and reported the extent to which the concept was related to the topic on a scale from 1 to 30. The survey results were as follows: first, students were not able to clearly distinguish between or understand the four main topics. Second, students organized their cognitive structures by closely associating related concepts after learning. Third, the presented concepts revealed a mixture of scientific and non-scientific concepts, suggesting that students needed to clearly distinguish the preconceptions through which they organized concepts, so that they are suitable for cognitive structures based on learning. Furthermore, non-scientific concepts within perceptions were consistently maintained throughout learning, affecting the proximity of scientific concepts.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제3권2호
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• pp.121-129
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• 1999

Photosynthesis and transpiration rates were simultaneously measured in attached sunflower leaves(Helianthus annuusL. cv. Russian Mammoth) during exposure to $NO_2$ and $O_3$ to determine the effect of mixed gan on photosynthesis and the stomatal aperture. The application of $O_3$ alone reduced both the net photosynthetic and transpiration rates. An analysis of the $CO_2$ diffusive resistances indicated that the main cause affecting photosynthesis reduction during $O_3$ exposure was not the internal gas phase of the leaf $(rCO_2^{liq})$ but rather the liquid phase or mesophyll diffusive resistance $(rCO_2^{liq})$, suggesting that there is a very concomitant relation between photosynthetic reduction and $rCO_2^{liq}$. The application of NO2 alone caused a marked reduction of the net photosynthesis yet no significant reduction of transpiration, indicating that NO2 affects the $CO_2$ fixation processes with no inluence on the stomatal aperture. A greter reduction in the photosynthesis of sunflower plants was caused by the application of $NO_2$ alone as compared to a combination of $NO_2$ and $O_3$. $NO_2$ alone reduced the photosynthetic rate by 90%, whereas a mixture of NO2 and O3 reduced it by 50%.

• 한국과학교육학회지
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• 제32권6호
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• pp.1050-1062
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• 2012

Concepts of science have been developed by occupying 'ecological niche' within conceptual ecology. The ecological niche is determined from the mutual effect between intellectual environmental of the learner and new concept, which few studies have been conducted. This study examined how the ecological niche of the concept of photosynthesis in $7^{th}$ grade is changed by instruction. The ecological niche was analyzed using 2 methods: (1) the change in the diversity of concepts, and (2) the change in the proximity of concepts based on the frequency and the relativeness score of the concepts. The concept of photosynthesis was analyzed in the 4 domains in the place of photosynthesis, products of photosynthesis, reactants of photosynthesis, and environmental factors. The results of this study are as follows: (1) reduced diversity of concepts, (2) increased frequency and relativeness score of the scientific concepts, and (3) increased proximity of the scientific concepts by instruction. With these results, the mutual effects of the concepts within the conceptual ecology have become active by class to differentiate the relationships between the concepts, which accordingly displayed their changes in status.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.251.2-251.2
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• 2013

Natural photosynthesis utilizes two proteins, photosystem I and photosystem II, to efficiently oxidize water and reduce NADP+ to NADPH. Artificial photosynthesis which mimics this process achieve water splitting through a two-step Z-schematic water splitting process using man-made synthetic materials for hydrogen fuel production. In this study, Z-scheme system was achieved from the hybrid materials which composed of hydrogen production part as photosystem I protein and water oxidizing part as semiconductor BiVO4. Utilizing photosystem I as the hydrogen evolving part overcomes the problems of existing hydrogen evolving p-type semiconductors such as water instability, expensive cost, few available choices and poor red light (>600 nm) absorbance. Some problems of photosystem II, oxygen evolving part of natural photosynthesis, such as demanding isolation process and D1 photo-damage can also be solved by utilizing BiVO4 as the oxygen evolving part. Preceding research has not suggested any protein-inorganic-hybrid Z-scheme composed of both materials from natural photosynthesis and artificial photosynthesis. In this study, to realize this Z-schematic electron transfer, diffusion step of electron carrier, which usually degrades natural photosynthesis efficiency, was eliminated. Instead, BiVO4 and Pt-photosystem I were all linked together by the mediator gold. Synthesized all-solid-state hybrid materials show enhanced hydrogen evolution ability directly from water when illuminated with visible light.

• ALGAE
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• 제28권4호
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• pp.355-363
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• 2013

The coralline alga, Corallina officinalis, is a widely distributed intertidal species in temperate coastal regions. It is usually exposed to high fluctuations of light intensity, light quality, temperature, and desiccation, all of which affect the temporal and spatial distribution as well as the morphology and the metabolism of this alga. In laboratory experiments we examined the effects of different light intensities (50, 100, and 200 ${\mu}mol$ photons $m^{-2}s^{-1}$) on photosynthesis, calcification, photosynthetic pigment contents (chlorophyll a and carotenoids), and growth rate of C. officinalis to clarify its photoacclimation strategies. Net photosynthesis, calcification and dissolution rates based on weight were not sensitive to irradiance. Although, photosynthesis and calcification did not clearly respond to light intensity, photosynthetic pigment contents were significantly lower at higher light intensities. In addition, higher irradiances induced significant enhancement of gross photosynthesis based on chlorophyll a. As a result, the specific growth rate was significantly stimulated by high light intensity. Our results suggest that photoacclimation of C. officinalis to different light conditions may be regulated to optimize growth.