In this study, the physicochemical and electrochemical properties of carbon nanomaterials and synthesized nano-carbon/Si composites were studied. The nano-carbon/Si composites were ball-milled to a nano size and coated with pyrolytic carbon using Chemical Vapor Deposition (CVD). They were then finely mixed with respective nano-carbon materials. The physicochemical properties of samples were analyzed using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Raman spectroscopy, X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), and surface area analyzer. The electrochemical characteristics were investigated using the galvanostatic charge-discharge and cyclic voltammetry (CV) measurements. Three-electrode cells were fabricated using the carbon nanomaterials and nano-carbon/Si composites as anode materials and LiPF₆ and LiClO₄ as electrolytes of Li secondary batteries. Reversibility using LiClO₄ as an electrolyte was superior to that of LiPF₆ as the electrolyte. The initial discharge capacities of nano-carbon/Si composites were increased compared to the initial discharge capacities of nano-carbon materials.

Oxidation-reduction cycling (ORC) procedures are widely used for cleaning nanoparticle surfaces when investigating their electrocatalytic activities. In this work, the effect of ORC on the surface structures and electrocatalytic oxygen reduction activity of Au electrodes is analyzed. Different structural changes and variations in electrocatalysis are observed depending on the initial structure of the Au electrodes, such as flat bulk, nanoporous, nanoplate, or dendritic Au. In particular, dendritic Au structures lost their sharp-edge morphology during the ORC process, resulting in a significant decrease in its electrocatalytic oxygen reduction activity. The results shown in this paper provide an insight into the pretreatment of nanoparticle-based electrodes during investigation of their electrocatalytic activities.

Efficient copper removal from water was achieved by using surface modified silica spheres with 3-mercaptopropyltrimethoxysilane (MPTMS) using base catalyst. The surface modification of silica spheres was performed by hydrolysis and condensation reactions of the MPTMS. The characteristic infrared absorption peaks at 2929, 1454, and 1343 cm⁻¹ represent the −CH₂ stretching vibration, asymmetric deformation, and deformation, respectively. The absorption peaks at 2580 and 693 cm⁻¹ corresponding the −SH stretching vibration and the C-S stretching vibration indicate the incorporation of MPTMS to the surface of silica spheres. Field emission scanning electron microscope (FESEM) image of the surface modified silica sphere (SMSS) shows nano-particles of MPTMS on the surface of silica spheres. High concentration of copper solution (1000 ppm) was used to test the copper removal efficiency and uptake capacity. The FESEM image of SMSS treated with the copper solution shows large number of copper lumps on the surface of SMSS. The copper concentration drastically decreased with increasing the amount of SMSS. The residual copper concentrations were analyzed using inductively coupled plasma mass spectrometer. The copper removal efficiency and uptake capacity with 1000 ppm of copper solution were 99.99 % and 125 mg/g, respectively.

Two new polymeric complexes, [Zn(dpa)(pyz)_0.5]_n (1; dpa = diphenate and pyz = pyrazine) and [Mn₃(bpdc)₃(py)₄]_n (2; bpdc = biphenyl-4,4'-dicarboxylate and py = pyridine) were successfully isolated by the hydro- and solvo-thermal technique, respectively. The complexes were characterized by elemental and thermal analysis, vibrational IR spectroscopy, and by single crystal x-ray structure determination. For 2, magnetic property was also investigated. Complex 1 is a two-dimensional layer structure consisting of a paddle-wheel building unit of Zn-dpa chains bridged by pyrazine. While, complex 2 consists of linear trimeric Mn3 cluster as building unit to form 3D network. In the complexes, dpa²⁻ (1) and bpdc²⁻(2) ligands show a typical bis-monodendate bridging and two kinds of bridging modes; a typical bridging and chelating/bridging mode, respectively.

This study explores the effective visual resources in the “regularity in chemical reactions” unit of ninth grade science textbooks (2009 revised version). The frequency and role of visual resources were initially examined, and the students’ perceptions of visual resources were investigated. The results of the analysis represented the learning material presentation (68%), motivational categories (14%), guide to inquiry procedures (9%), and inquiry results and summaries (8%). According to the investigation of the students’ perceptions of visual resources, the most effective visual resource for motivation is a photograph depicting physical and chemical changes, such as in bread baking and the most effective for learning material presentations in mass conservation, definite proportion, and stoichiometric concept units were a cartoon, graph, and formula representing stoichiometric phenomena, respectively. The most effective resource for guide to inquiry (experimental) procedures were photographs of both instruments and sequential experiment processes; and in the inquiry results and summary category, incomplete tables and graphs for students to work on themselves. The aims of this research are to increase the usefulness of visual resources in the teaching-learning activity and provide informative supplements for the development and improvement of visual resources, according to the students’ perceptions.

본 연구에서는 예비 화학 교사가 논의와 글쓰기가 강조된 탐구 중심 과학 수업을 개발하고 적용하는 과정에서 직면하는 어려움과 이를 극복해나가는 과정을 분석하였다. 이를 위해 예비 화학 교사가 각 주제 수업 개발 후, 10개 주제 전체 수업 개발 후, 각 주제 수업 수행 후, 10개 주제 전체 수업 수행 완료 후에 작성한 반성적 저널, 수업 지도안, 수업 녹음, 학생 작성 활동지 등을 분석하였다. 예비 화학 교사는 논의와 글쓰기를 강조한 탐구 수업 과정에서 자신의 과학 지식이 부족함을 인식하고 이후의 수업 준비에서는 철저한 과학 개념 확립을 위한 노력을 하였다. 학생 수준 파악의 어려움은 현장 경력교사의 조언, 학생들과의 상호작용, 교과서의 서술 내용 분석 등을 통하여 극복하려 노력하였다. 또한 다양하고 방대한 과학 수업 자료를 참고하여 탐구 중심 과학 수업 지도안을 개발하는데 어려움을 겪었고, 각 주제의 수업 목표를 명확히 세운 후 구체적인 교수-학습 활동을 선정할 수 있었다. 수업 시간을 효율적으로 운영하고 적극적인 학생 참여를 유도하는데도 어려움을 겪었고 현장 경력 교사의 조언을 토대로 격려와 통솔을 병행함으로써 향상되었다. 또한 수업을 진행하면서 논의와 글쓰기에 대한 구체적인 가이드 제공의 필요성을 느끼고 이를 실시하여 학생들의 논의 참여와 글쓰기 수준 향상을 도모하였다.

The goal of this study was to examine the current status of science teachers’ stage of concern (SOC) and level of use (LoU) on descriptive assessment and determine the relationship between SoC and LoU. To achieve this, concerns-based adoption model (CBAM) was used, and a survey was conducted on 138 science teachers. The data from this study were analyzed by frequency analysis, percentile analysis based on CBAM, χ² test, and Spearman correlation analysis. SoC and LoU of the science teachers observed in this study are as follows. First, the science teachers’ overall SoC for the descriptive assessment was low and showed a typical pattern of the initial stage when the program was introduced. Second, LoU analysis on descriptive assessment showed that the “mechanical Use” (N=49, 35.5%) or “routine” (N=48, 34.8%) accounted for the majority. Third, the Spearman correlation between SoC and LoU on descriptive assessment was .299(p<.01). This suggests that teachers’ SoC needs to be increased in order to promote higher LoU on descriptive assessment, which requires new alternative measures.

이 연구에서는 2009 개정 교육과정에 따른 교과서에서 제시하고 있는 이온 화합물의 설명 개념과 모형을 분석하고, 학생들이 이온 화합물에 대해 어떻게 이해하고 있는지 설문 검사하였다. 교과서 분석은 중학교 과학2 교과서 9종과 고등학교 화학 I과 화학 II 교과서 4종을 대상으로 하였고, 설문 검사는 중학교 2학년, 고등학교 1~3학년 학생 194명을 대상으로 실시하였다. 연구 결과는 다음과 같다. 첫째, 교과서 내용 분석 결과, 이온 화합물을 설명할 때 사용한 과학적 개념과 이를 표현하는 모형은 교과서 마다 차이가 있었다. 이온 화합물의 정의에서는 정전기적 인력, 강한 결합, 규칙적 배열, 결합비의 개념 중 몇 가지를, 이온 화합물의 성질에서는 녹는점, 부서짐, 용해, 전기 전도성 중 몇 가지를 선택적으로 제시하였다. 또한 설명 없이 모형만 제시하거나 설명만 하고 모형은 제시하지 않은 경우도 있었다. 이러한 차이는 중학교 과학2 교과서에서와 같이 이온 화합물에 대한 별도의 성취기준이 없는 경우와 결합비나 용해와 같이 학년별로 동일한 개념을 반복하여 다룰 때 더 크게 나타났다. 둘째, 이온 화합물에 대한 학생 설문 분석 결과, 이온의 형성 과정과 결합비를 설명할 때 과학적 개념을 잘 적용하지 못하였고 모형으로 표현하는 것을 어려워하였다.