• Journal of Korean Elementary Science Education
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• v.26 no.5
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• pp.551-557
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• 2007

The purpose of this study was to examine the questions in the 'Matter' units of elementary science textbooks under the 7th curriculum. For the analysis, a total of 338 questions were extracted from 15 units. Six criteria (recalling, recognizing, predictive, applied, divergent, and evaluative question) were reconstructed for textbook question analysis based on Blosser(1973)'s question category system for science. The results were as follows. First, there were more closed (recalling, recognizing, predictive, or applied) questions (72.2%) than open (divergent or evaluative) questions (27.8%) in elementary science textbooks. Second, cognitive-memory (recalling or recognizing) question type was the most frequently asked in all grade levels. Open (divergent or evaluative) questions increased according to grade level whereas convergent (predictive or applied) questions decreased. Third, question types were applied based on the characteristics of each unit rather than on children's developmental characteristics. Educational implications were discussed based on the results.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.640-645
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• 2001

The present study is to investigate the characteristics of the impulse waves discharged from the exit of the convergent and divergent pipes. An experiment is carried out using a shock tube with an open end and is compared to the computation of the axisymmetric, compressible, unsteady Euler equations, which are solved by the second-order total variation diminishing(TVD) scheme. For the computational work, some initial compression waves are assumed inside the pipe so that those are identical to the experimental ones of the shock tube. The results show that the peak pressures of the impulse waves discharged from the exit of convergent and divergent pipes decrease with an increase in the wavelength of the initial compression wave. All of the impulse waves have a strong directivity toward the pipe axis, regardless of the exit type of the pipe employed. The impulse waves discharged from the divergent pipe are stronger than those from the straight pipe, while the impulse waves of the convergent pipe are weaker than those from the straight pipe. It is believed that the convergent pipe can playa role of a passive control to reduce the peak pressure of the impulse wave. The present computations represent the experimented impulse waves with a good accuracy.

• Korean Institute of Interior Design Journal
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• v.16 no.2 s.61
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• pp.63-70
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• 2007

Analogy in problem solving is similarity-based reasoning facilitated by verbal and visual operation. This similarity-based reasoning generally supports initial phase of idea search. Therefore, this study intends to infer the types of problem solving by tracing the analogy use of verbal and visual representation through a experimental research. According to the result of this research, the types of problem solving by analogy are classified into 'evolving', 'divergent', and 'poor conversion' type. Firstly, 'evolving type' is distinguished between 'combination type' associated different contents to develope a new design and 'transformation type' associated similar words and sketches to be continuously revised and developed. In these types usually structural analogy rather than surface analogy is used. Secondly, in 'divergent type' associated words or sketches are individually represented, and among them one design solution is selected. In this type usually surface analogy is used. Thirdly, in 'poor conversion type' interaction between verbal representation and visual representation does not go on smoothly, and the generation of idea is poor. In here surface analogy is mostly used. These findings could form the basis of skill development of idea generation and conversion in design education.

• Journal of The Korean Association For Science Education
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• v.32 no.1
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• pp.129-145
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• 2012

This study investigated factors of creativity and interaction between factors that are revealed when gifted students designed scientific experiments. For this, we firstly developed items which required the written process of designing experiments to explore creativity factors. Then, we used these items as a part for letters of self-introduction to students who applied for 2011 correspondence education of general physics for the Korea Physics Olympiad. 513th letters of self-introduction which were analyzed to investigate factors of creativity in view of creativity definition after researchers' consultation, which specifically means a combination of divergent and convergent thinking. The results were as follows; (1) in the step of hypothesis building, we could not only find Originality and the Flexibility & Fluency, which were factors of divergent thinking, but also Coherency and Elaborateness, which were factors of convergent thinking. (2) in the step of the hypothesis testing, we could explore Originality, Flexibility & Fluency in divergent thinking and Coherency, Reliability, Clarity, Elaborateness in convergent thinking. (3) we also figured out three creativity types of gifted students from the viewpoint that creativity is a consequence of interaction between divergent thinking and convergent thinking; a) Type A showed divergent and convergent factors of creativity in the step of hypothesis building. However, type A did not include divergent factors of creativity on the process of the hypothesis testing. b) Type B had divergent and convergent factors of creativity on the process of the hypothesis testing, but it had not convergent factors of creativity on the step of hypothesis building. c) Finally, in Type C, only divergent factors of creativity appeared on the process of the hypothesis testing, but convergent factors of creativity could be found on the step of hypothesis building and hypothesis testing.

• Journal of Korea Water Resources Association
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• v.48 no.2
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• pp.137-147
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• 2015

This study performed the systematic classification of the various types of riffles and analyzed their physical and hydraulic characteristics at the Hongcheon River and Seomjin River. The riffles are classified into the long type and the wide type by their ratio of length and width, and also classified into the convergent type and the divergent type by their width change along flow direction. They are also classified into the falling type, the running type, the undular wave and the undular jump by their surface profiles. The falling type and the running type usually occur near the cobbles with multiple diameters, whereas the undular wave and the undular jump occur near the small pebbles. They showed the upward convex type at the middle part, and the slope gets bigger at the downstream part.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.5
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• pp.346-354
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• 2002

The present study is to investigate the propagation characteristics of the impulse waves discharged from the exit of the convergent and divergent pipes. An experiment is carried out using a shock tube with an open end and is compared to the computation of the axisymmetric, compressible, unsteady Euler equations, which are solved by the second-order total variation diminishing (TVD) scheme. For the computational work, several initial compression waves are assumed inside the pipe so that those are the same to the experimental ones of the shock tube. The results show that the peak pressures of the impulse waves discharged from the exit of convergent and divergent pipes decrease with an increase in the wavelength of the initial compression wave. All of the impulse waves have a strong directivity toward the pipe axis, regardless of the exit type of the pipe employed. The impulse waves discharged from the divergent pipe are stronger than those from the straight pipe, while the impulse waves of the convergent pipe are weaker than those from the straight pipe. It is found that the convergent pipe can play a role of a passive control to reduce the peak pressure of the impulse wave. The present computations represent the experimented impulse waves with a good accuracy.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.8
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• pp.543-548
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• 2011

New concept of wind energy conversion system is proposed to increase the energy density at a given working space. The quality of wind for wind power generation is depend on its direction and speed. However, the quality is not good on land because wind direction is changeable all the time and the speed as well. The most popularly operated wind turbine system is an axial-flow free turbine. But its conversion efficiency is less than 30% and even less than 20% considering the operating time. In this research, a cross-flow type wind turbine system is proposed with a convergent-divergent duct system to accelerate the low speed wind at the inlet of the wind turbine. Inlet guide vane is also introduced to the wind turbine system to have continuous power generation under the change of wind direction. In here, the availability of wind energy generation is evaluated with the change of the size of the inlet guide vane and the optimum geometry of the turbine impeller blade was found for the innovative wind power generation system.

• The Korean Journal of Zoology
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• v.30 no.4
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• pp.417-431
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• 1987

Isozyme analysis, morphometric comparison, and artificial hybridization test wereperformed to elucidate the patterns of genic variation, morphological differentiation, genetic incompatibility, and a probable path in speciation between two MDH allelotypes (MM type and MS type) of the Dark Chub Zacco temmincki, a fresh water fish inhabiting in Korean waters. The degree of genic variation of MS type(HD=.023, HG=.021) was twofold higher than that of MM type (HD=.013, HG=.014) but both allelotypes were far less than the average genic variation of fresh water Bish in general. The average genetic similarities among 7 populations of MM type and 6 Populations of MS type were S=.947 and S=.966 respectively, whereas the value between two allelotypes was S=.853. Presumed divergent time of two allelotypes was estimated to be about 700 thousand years ago. Discriminant function analysis based on 18 morphometric characters of 302 specimens representing 12 populations revealed no morphological difference between two allelotypes. Artificial hybridization test indicates that there is an obvious genetic incogpatibility between two allelotypes and therefore it is assumed that isolating mechanism is completed.

• Journal of Environmental Science International
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• v.11 no.10
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• pp.1011-1021
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• 2002

Fruit-discharge type of forty species of Asian Geranium were examined and their evolutionary trends and taxonomic system were discussed. Two main types of seed discharge in Geranium are made the basis of its divison into subgenera: Geranium subgenus Geranium, with a ballistic expulsion of the seed from mericarp, Geranium subgenus Robertium, with forcible discharge of the mericarp with the seed in it, separately from the awn. Variants of the seed ejecting type permit the division of Geranium subgenus Geranium into three sections. Section Ceranium, these has bristles at the base of the mericarp for prevent the seed from dropping from the divergent mericarp. Section Dissect, these has prongs at the base of the mericarp far prevent the seed from dropping from the divergent mericarp. Section Tuberosa, these has no bristles and prongs at the base of the mericarp, instead, retained of seed in pre-explosive interval by twist. Geranium subgenus Robertium was divided into two sections, Section Ruberta, with deeply wrinkled on the surface of mericarp at the time of discharge. Section Batrachioides, and section Trilopha, without wrinkle on the surface of mericarp at the time of discharge. According to the seed discharge, subgenus Geranium is thought to be more advanced than subgenus Robertium.

• Mycobiology
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• v.40 no.3
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• pp.147-150
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• 2012

This paper provides a description of Opegrapha herbarum, Opegrapha viridis and Phaeographis subdividens, all newly identified in the Republic of Korea. The characteristic features of O. herbarum include Varia-type asci, Subelevata-type ascospores, a lack of secondary metabolites and a saxicolous habitat. O. viridis possesses Calcarea-type asci, Vulgata-type ascospores and no chemicals in the thallus. P. subdividens is recognizable by its curved to sinuous lirellae, divergent labia, a brown and uniformly thick proper exciple which is open at its base, 3~4-septate ascospores, and lack of secondary metabolites. All three taxa are now reported to exist on Bogil Island in the Republic of Korea.