• 한국응용과학기술학회지
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• 제27권4호
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• pp.531-538
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• 2010

The electrochemistry characterization of metal is important in many industrial applications. In this study, we investigated the C-V diagrams related to the electrochemistry characterization of nickel. We determined electrochemical measurement by using cyclic voltammetry with a three electrode system. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650mV and measured to the initial point. The scan rate were 100, 150, 200 and 200mV/s. As a result, the C-V characterization of nickel using ethanolamine and ethylethanolamine inhibitor appeared irreversible process caused by the oxidation current from the cyclic voltammogram. After adding ethanolamine compound additive, adsorption film constituted, and the passive phenomena happened. According to the results by cyclic voltammetry method, it was revealed that the effect of the electrochemistry characterization of nickel depends on ethanolamine structure interaction to adsorption complex.

• Corrosion Science and Technology
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• 제4권3호
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• pp.114-119
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• 2005

Since the degradation caused by corrosion is restricted to the surface of materials, conventional ultrasonic nondestructive evaluation methods based on ultrasonic bulk waves are not applicable to characterization of the corrosion degradation. To take care of this difficulty, a new nondestructive evaluation method that uses ultrasonic backward radiation has been proposed recently. This paper explores the potential of this newly developed method for nondestructive characterization and in-situ monitoring of corrosion degradation. Specifically, backward radiated ultrasounds from aged thermo-mechanically controlled process (TMCP) steel specimens by corrosion fatigue were measured and their characteristics were correlated to those of the aged specimens. The excellent correlation observed in the present study demonstrates the high potential of the backward radiated ultrasound as an effective tool for nondestructive characterization of corrosion degradation. In addition, the potential of the backward radiated ultrasound to in-situ monitoring of corrosion degradation is under current investigation.

• 대한수학회보
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• 제59권2호
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• pp.407-417
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• 2022

Archimedes proved that for a point P on a parabola X and a chord AB of X parallel to the tangent of X at P, the area of the region bounded by the parabola X and the chord AB is four thirds of the area of the triangle ∆ABP. This property was proved to be a characteristic of parabolas, so called the Archimedean characterization of parabolas. In this article, we study strictly convex curves in the plane ℝ². As a result, first using a functional equation we establish a characterization theorem for quadrics. With the help of this characterization we give another proof of the Archimedean characterization of parabolas. Finally, we present two related conditions which are necessary and sufficient for a strictly convex curve in the plane to be an open arc of a parabola.

• Applied Microscopy
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• 제50권
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• pp.12.1-12.11
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• 2020

Hot stage microscopy (HSM) is a thermal analysis technique that combines the best properties of thermal analysis and microscopy. HSM is rapidly gaining interest in pharmaceuticals as well as in other fields as a regular characterization technique. In pharmaceuticals HSM is used to support differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA) observations and to detect small changes in the sample that may be missed by DSC and TGA during a thermal experiment. Study of various physical and chemical properties such sample morphology, crystalline nature, polymorphism, desolvation, miscibility, melting, solid state transitions and incompatibility between various pharmaceutical compounds can be carried out using HSM. HSM is also widely used to screen cocrystals, excipients and polymers for solid dispersions. With the advancements in research methodologies, it is now possible to use HSM in conjunction with other characterization techniques such as Fourier transform infrared spectroscopy (FTIR), DSC, Raman spectroscopy, scanning electron microscopy (SEM) which may have additional benefits over traditional characterization techniques for rapid and comprehensive solid state characterization.

• The Journal of Advanced Prosthodontics
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• 제4권3호
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• pp.121-126
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• 2012

PURPOSE. The aim of the study was to evaluate the effect of 3 silicone primers and 3 surface characterization of acrylic resin surface on bond strength between silicone elastomer and acrylic resin. MATERIALS AND METHODS. 96 Cosmesil silicones bonded to heat-curing acrylic resin were fabricated with the dimension of $75{\times}10{\times}3$ mm. The 3 primers used in this study were G611 platinum primer, A-330 Gold platinum primer, and cyanoacrylates resin. Specimens without primer were used as control. The 3 types of surface characterization done were retentive holes with 1.5 mm in diameter and 0.5 mm deep, retentive beads of 0.6 mm diameter and the third type which was plain without any characterization. The specimens were then checked for bond strength by subjecting them to $180^{\circ}$ peel test on a universal testing machine. The obtained results were then subjected to statistical analysis using 2-way ANOVA and Scheff$\acute{e}$ multiple post hoc procedures. The statistical significance was set at 5% level of significance. RESULTS. The maximum bond strength was seen for samples in which A-330G primer was used followed by G611 primer. The control group showed the minimum bond strength. Surface characterization of retentive holes increased the bond strength considerably as compared to retentive beads and samples without any surface characterization. CONCLUSION. Within the limitations of the study, A-330G primer was more compatible with Cosmesil M511 silicone and has better bonding of Cosmesil to acrylic resin. Retentive holes made on acrylic surface increased the bond strength considerably than those without any surface characterization.

• 한국컴퓨터정보학회논문지
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• 제11권2호
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• pp.43-52
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• 2006

최근 유비쿼터스 컴퓨팅의 관심이 증대되면서, 방대하고 다양한 형태의 데이터에 대한 효율성과 효과성을 고려한 지식 탐사연구의 필요성이 요구된다. 공간 특성화 방법은 공간과 비공간 속성들을 고려하여 특성화 지식을 발견하는 방법으로, 기존의 특성화 방법을 확장하여 공간 영역에 대한 다양한 형태의 지식을 발견할 수 있다. 기존 공간 특성화기법에 대한 연구들은 다음과 같은 문제점을 가진다. 첫째, 기존의 연구는 탐사된 지식의 결과가 다각적인 공간 분석을 수행하지 못하는 문제점을 가진다 둘째, 공간 탐색 시 사용자에 의해 미리 정해진 위치 영역만을 고려하여 탐색함으로 유용한 지식탐사를 보장하지 못하는 문제점을 가진다. 따라서 본 연구에서는 밀도 기반의 클러스터링이 적용된 새로운 공간 특성화기법을 제안한다.

• 한국응용과학기술학회지
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• 제28권1호
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• pp.48-56
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• 2011

In this study, we investigated the C-V diagrams and metal surface related to the electrochemistry characterization of metal(nickel, SUS-304). We determined electrochemical measurement by using cyclic voltammetry with a three-electrode system. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate were 50, 100, 150, 200 and 250 mV/s. As a result, the C-V characterization of metal using N,N-dimethylacetamide and N,N-dimethylformamide inhibitors appeared irreversible process caused by the oxidation current from the cyclic voltammogram. After adding organic corrosion inhibitors, adsorption film constituted, and the passive phenomena happened. According to the results by cyclic voltammetry method, it was revealed that the addition of inhibitors containing amide functional group enhances the corrosion resistance properties.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2009년도 특별 심포지엄
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• pp.47-56
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• 2009

Proper reservoir characterization is an integral part of formation evaluation, reserve estimation and planning of field development. Seismic inversion is a widely employed reservoir characterization tool that provides various rock properties of reservoir intervals. This study presents results of the inversion studies including Geostatistical Inversion carried out on the gas fields, offshore Myanmar. Higher resolution and multiple models can be produced by Geostatistical Inversion using input data such as pre-stack seismic data, well logs, petrophysical relationships and geological inferences for example reservoir shape and lateral extent. Detailed reservoir characterization was required for the development plan of gas fields, and the Geostatistical Inversion studies served as a basis for integrated geological modeling and development well planning.

• Advances in aircraft and spacecraft science
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• 제2권3호
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• pp.249-261
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• 2015

The mechanical characterization of composite materials is nowadays a major interest due to their increasing use in the aeronautic industry. The design of most of these materials is based on their stiffness, which is mainly obtained by means of tensile tests with strain gauge measurement. For thin laminated composites, this classical method requires adequate samples with specific orientation and does not provide all the independent elastic constants. Regarding ultrasonic characterization, especially immersion technique, only one specimen is needed and the entire determination of the stiffness tensor is possible. This paper presents a study of different methods to determine the mechanical properties of transversely isotropic carbon fibre composite materials (gauge and correlation strain measurement during tensile tests, ultrasonic immersion technique). Results are compared to ISO standards and manufacturer data to evaluate the accuracy of these techniques.

• 호남수학학술지
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• 제35권3호
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• pp.329-342
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• 2013

We study lightlike hypersurfaces M of a semi-Riemannian space form $\tilde{M}(c)$ with a semi-symmetric non-metric connection whose structure vector field is tangent to M. Our main result is two characterization theorems for such a lightlike hypersurface.