• 대한수학교육학회지:학교수학
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• 제12권4호
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• pp.493-506
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• 2010

본 연구에서는 사범대학 수학교육과의 '수학문제해결방법론' 강좌 시간을 이용하여 학교 수학의 효과적인 교수-학습을 위한 교육 활동을 실행하였다. 예비 수학 교사들을 대상으로 수학의 내용 이해와 지도에 도움을 줄 수 있는 시각적 자료를 탐구하도록 하고, 조별로 동료 학생들에게 그 내용을 지도하는 발표 수업을 진행하였다. 본 연구의 실행 과정을 통해 예비 수학 교사들은 자신의 수학 학습에 대한 인지적, 정의적 측면의 긍정적인 변화를 경험하였고, 수학 학습에 대한 인식의 변화, 자신의 수학 학습에 대한 반성, 교사로서 준비해야 할 점 등에 대해 깊이 생각해 보는 학습의 기회를 가지게 되었다. 본 연구에서 실행한 바와 같은 지도 사례는 학교 수학의 문제 해결 지도를 위한 예비 수학 교사들의 실천 지향적인 활동을 통해 그들의 교수 내용 지식의 성장을 도울 수 있다. 또한 직관이나 구체적인 조작 활동에 바탕을 둔 통찰 등의 수학적 경험을 제공해야 한다는 2007 개정 교육과정의 교수-학습 제안을 예비 수학 교사들이 실제 수업의 현장에서 구체화하는 데에도 도움을 줄 수 있다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 추계학술발표대회 논문집
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• pp.167-170
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• 2004

In order to investigate the impact behaviors of 3-D braided glass/epoxy composites, the energy profiles and damage area were compared to the laminates of similar volume fraction and composition. The energy profiles showed different characteristics from each other which indicates they have distict energy absorption mechanisms. The image analysis on the damage projections visualized the crack propagation paths along the fiber direction.

• Applied Microscopy
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• 제48권4호
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• pp.128-129
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• 2018

Soft ferromagnetic materials are utilized for various electromagnetic devices such as magnetic recording heads and magnetic shielding. In situ observation of magnetic microstructures and domain wall motions are prerequisite for understanding and improving their magnetic properties. In this work, by the Fresnel (out-of-focus) method of Lorentz microscopy, we observe the domain wall motions of polycrystalline Ni/Ti thin film layers triggered by single-shot laser pulse. Random motions of domain walls were visualized at every single pulse.

• 동력기계공학회지
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• 제8권3호
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• pp.52-57
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• 2004

A new non-destructive inspection technique has been developed. One characteristic of the technique is that defects are visualized by laser ray. Magnetic domains and domain walls of a magneto-optical sensor(MO sensor) are varied by the magnetic flux leaked by defects, and the variations are observed by the reflected light of the laser ray. The information of defect can remotely be inspected by this technique in a real time. This paper describes the results estimated on the 2-dimensional surface defects and opposite-side defects in a ferromagnetic material and the natural surface defect in a clutch disk wheel. The light region of a visible image and the magnitude of a reflected light increases as the input current of the magnetizer increases. The natural surface defect, that has not the width of crack's open mouth, can be also visualized like as 2-dimensional artificial defects.

• 한국임상수의학회지
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• 제18권3호
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• pp.211-214
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• 2001

The embolic effect of Gelfoam was investigated for transarterial embolization of renal artery (TAE-RA) in four normal rabbits. The catheter was selectively introduced into the unilateral renal artery under fluoroscopy and the Gelfoam-iohexol mixture was infused through a catheter into the renal arteries of 4 rabbits. The immediate and delayed (8 weeks) embolic effects on the renal arteries was investigated with selective angiography. The Gelfoam-iohexol was visualized under fluorosxopy in four rabbits. Renal arteries were ablated immediately after TAE-RA in four rabbits, however, opacification of renal parenchyma was visualized by injected contrast agent in 3 rabbits at 8 weeks. The Gelfoam-iohexol can be used as a short-term embolic materials for TAE-RA, however it is not adequate for permanent embolization of renal artery.

• 한국철도학회논문집
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• 제10권2호
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• pp.103-111
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• 2007

The existing design materials by document type are restricted in searching and acquiring necessary design information because the materials consist of huge information and various document types. This study suggests a methodology to develop an electronic technical manual that can manage construction design materials by XML-base integrated information system. Electronic technical manual for design materials can provide visualized information through various multimedia tools such as multi-link, virtual reality and animation. Using an integrated electronic manual for construction project can prevent to miss necessary design information. The results of this study includes a data flow diagram to develop an interactive electronic technical manual (IETM) for construction design information. Finally the study suggests some scenarios for practical use and quantitative analysis of application effect analysis by AHP method.

• Applied Microscopy
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• 제36권spc1호
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• pp.63-69
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• 2006

By utilizing a field emission gun and a biprism installed on a transmission electron microscope (TEM), electron holography is extensively carried out to visualize the electric and magnetic fields of nanomaterials. In the electric field analysis, the distribution of electric potential in a sharp tip made of W coated with $ZrO_2$ is visualized by applying the voltage to the tip. Denser contour lines due to the electric potential are observed with an increase in the bias voltage. In the magnetic field analysis by producing the strong magnetic field with a sharp magnetic needle made of a permanent magnet, the in situ experiment is carried out to investigate the magnetization of hard magnetic materials. The results of these experiments clearly demonstrate that electron holography is a promising advanced transmission electron microscopy technique to characterize the electric and magnetic properties of nanomaterials.

• 한국재료학회지
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• 제14권6호
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• pp.436-442
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• 2004

Elastic and plastic deformation behaviors of the high purity aluminum and the silica glass were studied using nanoindentation and finite element analysis(FEA) techniques. Berkovich- and cone-type indenters were used for the nanoindentation test. Deformation behaviors and nanoindent profiles of elastic, elastic-plastic or plastic materials were clearly visualized by FEA simulation. Effects of the penetration depth and strain hardening on the deformation behavior were examined. Pile-up and sink-in behaviors were studied by using FEA technique. Degree of pile-up or sink-in was found to be a function of the ratio of elastic modulus to yield strength of materials. FEA was found to be an effective method to study deformation behaviors of materials under nanoindentation, especially in the case when pile-up or sink-in phenomena occurred.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1994년도 춘계학술대회 논문집
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• pp.175-182
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• 1994

Effect of some process variables including area reduction, stroke advance, materials on the extrusion load, plastic flow and height ratio of upper to lower extruded parts in the cup-cup axisymmetric extrusion were experimentally investigated and analyzed. Deformed pattern is visualized by grid-marking technique using half-cut billets splitted. The influence of using split specimen and original specimen on the extrusion load and height ratio is examined by experiment.

• 연구논문집
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• 통권25호
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• pp.129-135
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• 1995

This study discribes characteristics of water spray for extinguishment of gasoline pool fire. Experiments are carried out for the gasoline pool fire in a small tank with a diameter of 150mm and a height of 8mm. Droplet size, spray pressure, amount of water which reaches the flame base and velocity of water spray are measured to find extinguishment conditions and air entrainment due to the water spray is visualized. Critical conditions of water spray for extinguishment of gasoline pool fire is quantitatively shown.