• Journal of the Korean Chemical Society
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• v.45 no.4
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• pp.370-376
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• 2001

In this study, high school students' problem-solving strategy-performing ability was measured by an essay-type test. The relationship between students' logical thinking ability and strategy-performing ability was also investigated. Four classes (N=187) were selected from two high schools in Seoul, and the strategy performance ability test and the Group Assessment of Logical Thinking (GALT) were administered. Evaluation scheme for strategy-performing ability consists of 7 subcategories - understanding given of problems, recalling related law, setting up subgoals, deriving physical quantities, logical progress, mathematical execution, and reviewing. The intercoder agreement for scaling was .92, which indicated substantial strength of agreement. The results revealed that students' ability of understanding given of problems and mathematical execution was relatively high. However, their ability of setting up subgoals and reviewing was very low. The total scores of the strategy performance ability test and all of the scores of each subcategory were significantly correlated with the GALT scores.

• Journal of the Korean Chemical Society
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• v.56 no.1
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• pp.137-143
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• 2012

This study analyzed the questions posted on the chemistry Q&A board by students and teachers in a chemistry education homepage, in order to understand the difficulties in learning and teaching chemistry. The different tendencies were found in the contents and the motivations of questions by students and teachers. In Chemistry I, students raised many questions in the 'Water' unit, while teachers raised many ones in the 'Chemical compound in our life' unit. In Chemistry II, students asked many questions in the 'Gas, liquid, solid' unit, while teachers did in 'Chemical reaction and energy' unit. Students' motivations of questioning were 'Explanation of unclear concept', and 'Problem solving', while teachers' motivations were 'Searching information', and 'Question in experiment'. The Q&A board provided a field in exchanging informations needed in learning and teaching chemistry. Educational implications were discussed on the use of Q&A board in chemistry education.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1735-1737
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• 2005

We obtain probabilities at a crossing of two linearly time-dependent potentials that are constantly coupled to the other by solving a time-dependent Schrödinger equation. We find that the system which was initially localized at one state evolves to split into both states at the crossing. The probability splitting depends on the coupling strength $V_0$ such that the system stays at the initial state in its entirety when $V_0$ = 0 while it is divided equally in both states when $V_0 \rightarrow {\infty}$ . For a finite coupling the probability branching at the crossing is not even and thus a complete probability transfer at $t \rightarrow {\infty}$ is not achieved in the linear potential crossing problem. The Landau-Zener formula for transition probability at $t \rightarrow {\infty}$ is expressed in terms of the probabilities at the crossing.

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.285-288
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• 2004

A canonical transformation changes variables such as coordinates and momenta to new variables preserving either the Poisson bracket or the commutation relations depending on whether the problem is classical or quantal respectively. Classically canonical transformations are well established as a powerful tool for solving differential equations. Quantum canonical transformations have been defined and used relatively recently because of the non-commutativeness of the quantum variables. Three elementary canonical transformations and their composite transformations have quantum implementations. Quantum canonical transformations have been mostly used in time-independent Schrodinger equations and a harmonic oscillator with time-dependent angular frequency is probably the only time-dependent problem solved by these transformations. In this work, we apply quantum canonical transformations to a harmonic oscillator in which both angular frequency and equilibrium position are time-dependent.

• Journal of the Korean Magnetic Resonance Society
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• v.6 no.2
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• pp.142-154
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• 2002

One of the oldest, still unsolved, and often ignored problems in magnetic resonance remains the issue of how to observe undistorted, normal one-dimensional spectra where the frequencies and their relative intensities represent faithfully the distribution of spins and sites in the sample within the magnet. Often distortions in these parameters are accepted, as the price of sensitivity enhancement, or because it is unclear just how these distortions might be avoided. Surprisingly enough, the problem is exacerbated by the use of modern techniques of pulsed Fourier transform NMR. Noise spectroscopy is an approach to solving the problem of distorted NMR spectra, which is largely under appreciated; it promises virtually "unlimited" distortionless bandwidths without costly hardware investments. Nonetheless, its exploitation remains limited. We will discuss why noise spectroscopy belongs in the arsenal of tricks spectroscopists should be aware of, show examples where its use is essential if accurate, quantitative NMR is to be expected, and discuss some recent approaches which extend its applicability yet further, particularly in solid state NMR and in applications to quadrupolar nuclear spins.

• Journal of the Korean Chemical Society
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• v.68 no.1
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• pp.40-53
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• 2024

The study investigates the number and proportion of questions in each area by examining Chemistry I questions from the College Scholastic Ability Test from 2019 to 2022. The analysis was conducted using a three-dimensional framework that included key concepts in chemistry, behavioral domains in chemistry, and behavioral domains in mathematics. The results indicated that Chemistry I questions on the College Scholastic Ability Test had a relatively even distribution of questions across core individual topics, but highly difficult questions were predominantly biased toward stoichiometry. In terms of the behavioral domains in chemistry, there was a remarkably low proportion of questions related to problem recognition and hypothesis establishment, as well as designing research and implementing research. Conversely, highly difficult questions were more inclined towards drawing conclusions and evaluations. Regarding behavioral domains in mathematics, there was a limited number of questions addressing heuristic reasoning and deductive reasoning. On the other hand, high-difficulty questions favored internal problem-solving ability. Additionally, certain key concepts in chemistry and behavioral domains in chemistry exhibited a strong correlation with specific behavioral domains in mathematics. This characteristic was particularly evident in questions that encompassed higher-dimensional behavioral domains in mathematics, which students tend to find challenging.

• Journal of The Korean Association For Science Education
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• v.38 no.5
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• pp.611-623
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• 2018

This study investigated verbal behaviors and interactions in the processes of making written test items using paired think aloud problem solving for pre-service secondary chemistry teachers. The processes of making written test items using paired think-aloud problem solving in four small groups consisting of two pre-service chemistry teachers were recorded and transcribed. The analysis of the results revealed that 'item making' for ten subcategories for solver's verbal behaviors were most frequently exhibited regardless of 'integration' among the components of pedagogical content knowledge (PCK). The solver's 'provide', 'modify', 'require agreement', 'ask', 'agree', and 'justify' were also frequently exhibited although fewer than 'item making'. Especially, the solver's 'ask' was more frequently used in 'non-integration', whereas 'justify' was more frequently used in 'integration'. In listener's verbal behaviors consisted of eight subcategories, 'point out', 'ask', and 'agree' were frequently exhibited regardless of 'integration'. Listener's 'ask' and 'agree' were exhibited more in 'non-integration', whereas 'point out' was exhibited more in 'integration'. Many verbal interactions were analyzed to be in 'symmetrical type' more than 'solver-dominant type' or 'listener-dominant type'. 'Symmetrical type' was also more frequently exhibited in 'integration', whereas 'solver-dominant type' was more frequently exhibited in 'non-integration'. There were little differences between 'integration' and 'non-integration' in 'listener-dominant type'. In 23 subcategories of 'symmetrical type', 'ask-provide' and 'point out-justify' were most frequently found. Especially, 'ask-provide' was more frequently found in 'non-integration', whereas 'point out-justify' was more frequently found in 'integration'. 'Point out-modify' was the most frequent in 4 subcategories of 'listener-dominant type', while 'item making-agree' in three subcategories of 'solver-dominant type' regardless of 'integration'. However, only a little of other subcategories of the three types were found.

• Journal of the Korean Chemical Society
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• v.47 no.2
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• pp.165-174
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• 2003

The purposes of this study were to investigate the correlation between the cognitive level and the probabilistic thinking level and to analyze the effects of the probability activities in Thinking Science (TS) program on the development of probabilistic thinking. The 219 7th grade students were sampled in the middle school and were divided into an experimental group and a control group. The probability activities in TS program were implemented to the experimental group, while only normal curriculum was conducted in the control group. The results of this study showed that most of 7th grade students were in the concrete operational stage and used both subjective and quantitative strategy simultaneously in probability problem solving. It was also found that the higher the cognitive level of the students, the higher the probabilistic thinking level of them. The sample space and the probability of an event in the constructs of probability were first developed as compared to the probability comparisons and the conditional probability. The probability activities encouraged the students to use quantitative strategy in probability problem solving and to recognize probability of an event. Especially, the effectiveness was relatively higher for the students in the mid concrete operational stage than those in any other stage.

• Journal of The Korean Association For Science Education
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• v.30 no.8
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• pp.988-1001
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• 2010

The purpose of this research was to investigate how the peer review activity of lab report in the problem-solving experiment effected on the description ability and the quality improvement. The students who were taking the general chemistry experiment course were the subjects for this study. They finished lab reports and received peer review from their peers more than two times. The students who got feedback answered on peer review, revised their reports, and subsequently, completed final reports. The result showed that peer review affected the qualitative improvement of the lab report, specially in the process of 'designing experiment' and 'drawing conclusion and evaluation'. Students could organize their thoughts through writing lab reports. During this process, peer review activities provided the opportunity of self-examination and the way for viewing as objective standpoint. Moreover, the activities established communication fields for exchanging mutual opinions and learning.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.527-535
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• 2021

The STEAM education was applied to science high school students, and changes in perceptions of students and teachers were investigated after class treatment. By the results of the student's perception survey, very positive results were found in increasing problem-solving capabilities, educational satisfaction, etc. More than 98% of students said they would continue to participate in STEAM education classes. Meanwhile, the lack of time for class activities put a burden on students to complete the problems during class. Especially nanoscience content and activities were properly organized in consideration of the level of cognitive development of the students. In addition, as a result of a survey of teachers' perceptions for students, more than 80.0% of teachers responded very positively in 'self-directed learning ability' and 'problem-solving capability', etc.