• 한국세라믹학회지
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• 제35권11호
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• pp.1162-1170
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• 1998

PbO-TiO2-B2O3-BaO 계 유리상에서 PbTiO3의 결정화 메커니즘에 대한 이론적 고찰 및 전자현미경 관찰 그리고 결정화 기구의 열시차 분석에 대한 응용성을 조사하였다. 열시차 분석에 대한 Kissinger 식의 응용은 DTA 분석시 시료내 핵밀도가 변하지 않을 때 적용할 수 있으며, 표면결정화를 유도하기 위해 분말시료를 사용하는 경우도 활성화 에너지를 시료의 결정화 메커니즘에 크게 영향을 받는다. Ozawa 식에 의한 Avrami parameter n은 전자현미경 관찰에 의해 파악된 결정화메커니즘과 잘 일치하고 있었으며, 수정 Kissinger 식은 시료의 결정화 메커니즘을 반영하고 있어 시료의 전처리와 관계없이 참값의 활성화에너지를 구할 수 있다.

• 한국산업융합학회 논문집
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• 제25권3호
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• pp.461-466
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• 2022

Epoxy resins are widely used in various industrial fields. However, they suffer from brittleness, an issue that must be addressed for further applications. To solve this problem, additional fillers are needed to improve the mechanical and thermal properties of the resins; zirconia is one such filler. However, it has been reported that aggregation may occur in the epoxy composites as the amount of zirconia increases, preventing enhancement of the mechanical strength of the epoxy composites. Herein, to reduce the aggregation, zirconia was well dispersed on halloysite nanotubes (HNTs), which have high thermal and mechanical strength, by a conventional wet impregnation method using zirconyl chloride octahydrate as a precursor. The mechanical and thermal strengths of the epoxy composites with The zirconia impregnated HNTs (Zr/HNT) were investigated. Zr/HNT were characterized by Scanning electron microscope (SEM), transmittance electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy. The thermal strength of the epoxy composites was studied by thermomechanical analysis (TMA) and the mechanical strength of the epoxy composites (flexural strength) was studied by using a universal testing machine (UTM). The mechanical and thermal strengths of the epoxy complex with Zr/HNT were improved compared to those of the epoxy complex with HNT, and also increased as the content of Zr/HNT increased.

• 센서학회지
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• 제10권2호
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• pp.125-133
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• 2001

전도성 고분자 센서 (Conducting polymer sensors)는 상온에서 휘발성 유기 화합물 가스 (Volitile organic compounds gases)에 대해 감도를 가지고 있다. 화학 중합으로 제조된 전도성고분자인 polypyrrole과 polyaniline로 이루어진 8개의 센서 어레이를 이용하여 VOCs 가스에 대한 감응 특성을 살펴보았다. 화학 중합으로 합성된 각 센서들은 증류된 pyrrole, aniline과 dopant로 dodecylbenzene sulfonic acid (DBSA)와 산화제로 ammonium persulfate (APS) 그리고 증류수를 이용하여 제조되었으며, 각 센서들의 특성 부여를 위해 redoping과 dedoping은 전기화합법을 이용하여 제조하였다. Dedoping 법은 전압을 반대로 걸어주어 처음 첨가된 dopant를 전해질 속으로 빼냈으며, redoping법은 1-octanesulfonic acid sodium salt를 화합중합으로 형성된 막에 다시 첨가 시켰다. 감도와 가역성은 doping, dedoping, redoping 그리고 두께에 따라 영향을 받는다는 것을 알 수 있었다. 이들 전도성 고분자의 구조와 감도와의 관계를 scanning electron microscope (SEM), scanning probe microscope (SPM) 그리고 $\alpha$-step을 사용하여 조사하였다.

• 한국세라믹학회지
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• 제39권9호
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• pp.884-889
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• 2002

나노 결정질 $ZrO_2$ 박막을 제조하여 박막의 표면에서 인산칼슘을 유도하는 능력을 편가하기 위하여, 지르코늄 나프테네이트를 출발물질로 사용하고 화학적 용액법을 이용하여, $ZrO_2/Si$ 구조를 제작하였다. 코팅용액을 (100)Si 기판 위에 스핀코팅한 후, 500$^{\circ}C$에서 10분간 전열처리와 800$^{\circ}C$에서 30분간 최종열처리를 행하였고, 모든 열처리는 공기분위기에서 실시하였다. X-ray diffraction analysis를 이용하여 열처리된 박막의 결정화도를 조사하였고, 표면의 미세구조와 표면 거칠기를 field emission-scanning electron microscope와 atomic force microscope를 이용하여 관찰하였다. 열처리 후의 박막은 표면에 미세한 $ZrO_2$ 나노 결정이 생성되어 있었으며, 박막의 계면은 매우 균질 하였다. 유사생채용액에 1일 및 5일간 침적된 샘플의 표면위에 형성된 인산칼슘을 energy dispersive X-ray spectrometer를 이용하여 관찰하였고, fourier transform infrared spectroscopy를 이용하여 인산칼슘에 카본이 치환되어 있음을 확인하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.13-18
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• 2001

In this paper, FFT(Fast Fourier Transform) analysis of friction was suggested as a method to interpret the contact conditions. Micro-grooves with various dimensions were fabricated on the silicon surface to investigate the frictional behavior with respect to the change in geometrical contact condition. Frictional forces between micro-grooved surfaces and spheres modeled as surface asperities were measured using a micro-tribotester which was built inside a SEM(Scanning Electron Microscope). The experimental results show that the relative dimensions and distributions of contact asperities between two surfaces can be predicted by the power spectrum and the main frequency in FFT-based analysis of friction coefficient. Also, it was shown that the friction coefficient for multi-asperities was the result of the superposition of that for each asperity.

• 한국환경보건학회지
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• 제30권2호
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• pp.108-114
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• 2004

Observation of microorganisms collected from contaminated soils has been mainly conducted by using microscopy. Microscopic measurement is occupied an important part of the microorganism experiment, and is used as an important tool to count microorganisms as well as to observe cellular form and mode of life in the field of soil microbe observation. In general, observation equipments for soil microbes consist of electron microscope, camera, frame grabber (image acquisition baud), and image analysis software. Because image analysis software should be linked with frame grabber most equipments have to be imported as the package form. Therefore, the observation system is very expensive and difficult to be operated. In this study, soil microbes＇ observation equipment with the vision system which is easy operated and cheaper than imported one was developed and tested. The efficiency of image capturing and data aquisition with developed frame grabber and software in this experiment was good enough to analyze the image of soil microorganism.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.180-181
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• 2019

In this study, in order to find new uses for CBS dust, the chemical components of CBS dust were analyzed and effectively proposed a method. Chemical analysis shows that CBS dust contains a large amount of alkali in addition to chloride therefore, if CBS dust is used for secondary concrete products that use high amounts of mixed materials without rebars, it will be found that it can be used effectively for enhancing strength by active alkali.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.144-147
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• 2000

The effect of accelerated aging test on ethylene-propylene-diene monomer(EPDM) rubber used for outdoor insulation was studied by X-ray photoelectron spectroscopy(XPS), scanning electron microscope(SEM), FFT spectrum alalysis, and electrical pulse counts using PC by oscilloscope(300 MHz). In electrical alalysis, FFT spectrum analysis indicated arcing caused a significant increase in the third harmonic content of the leakage current of polluted insulator. Also, pulse counts increased as aging time. The surface oxygen and aluminum content were found to increase and that of carbon and nitrogen were found to decrease with time. The detailed XPS analysis indicated that the concentration of carbon in C-C decreased and concentration of highly oxidized carbons increased with time, which was due to the oxidation of EPDM rubber polymer SEM analysis indicated that crack and erosion of EPDM rubber occurred with time.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.441-442
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• 2012

SnNb2O6 nanoplates were prepared by a solvothermal synthesis with water and ethanol mixed solvent. For improvement of their properties, as-prepared SnNb2O6 nanoplates also were calcined. The prepared powder was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Transmission electron microscope (TEM), UV-vis spectroscopy, Raman spectrometer, Brunauer-Emmett-Teller (BET). The calcined nanoplates have a smaller surface area than the as-prepared nanoplates have. Nevertheless, in the case of the optical absorption properties, the calcined nanoplates could absorb more photon energy, due to their smaller band gaps. The Raman analysis revealed that the Nb-O bond length in the calcined nanoplates was longer than that in the as-prepared nanoplate. The higher optical absorption capability of the calcined nanoplates was attributed to the local structure variation within them. Furthermore the high crystallinity of the calcined nanoplates is effective in improving the generation of charge carriers. So, It was found that the calcined nanoplates exhibited superior photocatalytic activity for the evolution of H2 from an aqueous methanol solution than the as-prepared nanoplates under UV and visible irradiation. Therefore, the enhanced photocatalytic activity of the calcined nanoplate powder for H2 evolution was mainly attributed to its high crystallinity and improved optical absorption property resulting from the variation of the crystal structure.

• 한국결정성장학회지
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• 제30권5호
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• pp.163-167
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• 2020

본 연구에서는 PVT(Physical Vapor Transport) 방법을 이용하여 반도체 식각 공정용 소재로 사용되는 링 모양의 SiC(Silicon carbide) 다결정을 제조하였다. 흑연 도가니 내부에 원기둥 모양의 흑연 구조물을 배치하여 PVT법에 의한 링 모양의 SiC 다결정을 성장시켰다. 성장된 결정은 Raman 및 UVF(Ultra Violet Fluorescence) 분석을 이용하여 결정의 상분석을 하였고, SEM(Scanning Electron Microscope), EDS(Energy Dispersive Spectroscopy) 분석을 통해 미세조직 및 성분을 확인하였다. PVT 성장 초기의 온도변화를 통하여 SiC 다결정의 결정립 크기와 성장 속도를 조절할 수 있었다.