• Journal of Pharmaceutical Investigation
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• 제20권1호
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• pp.35-42
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• 1990

A new form of sulfabenzamide was characterized using X-ray diffraction patterns and differential scanning calorimetry. Solubility studies demonstrated that, of the sulfabenzamide polymorphs, the new form was more soluble than form I. Compression of the new form at compression force of 1000 $kg/cm{^2}$ didn't induce polymorphic change in the crystal. Similar patterns were also produced through grinding. The effects of some diluents on the polymorphic transformation from the new form into form I by grinding and compression were also studied. Three diluents, $Avicel^{\circledR}$, lactose and starch showed no influence on the polymorphic transformation. The new form seemed to be more suitable for the pharmaceutical preparation.

• 한국안광학회지
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• 제4권1호
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• pp.37-43
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• 1999

굴절률이 같은 안경렌즈에 탄성파를 이용한 단색광의 회절무늬로부터 렌즈에 전달되는 탄성파의 속도를 측정하여 렌즈의 불량 유무(有無)를 확인 할 수 있다. 광학적 heterodyne 방법으로 광의 회절무늬를 얻어 종 탄성파의 속도를 측정한 결과 안경렌즈의 경우 중굴절 렌즈는 평균 6588.5575 m/s이고, 고굴절 렌즈는 평균 3973.53 m/s로 측정되었다.

• 한국표면공학회지
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• 제20권2호
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• pp.43-48
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• 1987

Chromium and Aluminum films were deposited by evaporation technique in $3{\times}10^{-6}$ mbar vacuum level at the incident angles ranging from $0^{\circ}\;to\;60^{\circ}$ with various evaporation rates. We measured the sheet resistances and light transmittances, and observed diffraction patterns by TEM of these films. Relations among diffraction patterns, sheet resistances and light transmittances were discussed. The sheet resistances and light transmittances were shown the lowest values at 25$^{\circ}C$ of incident angle for all kinds of evaporation rates.

• Bulletin of the Korean Chemical Society
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• 제14권1호
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• pp.38-42
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• 1993

Factor analysis was applied to study the thermal decomposition of barium titanyl oxalate (BTO) which is used as the precursor of barium titanate. BTO was synthesized in $H_2O$ solvent and calcined at various temperatures. The X-ray diffraction patterns were obtained to make the data matrix of peak intensity vs. 2${\theta}$. Abstract factor analysis and target transformation factor analysis were applied to this data matrix. It has been found that the synthesized BTO consists of the crystals of $BaC_2O_4{\cdot}0.5H_2O\;and\;BaC_2O_4{\cdot}2H_2O$ as well as the amorphous solid of TiO-oxalate. The results also indicate that the BTO was transformed via $BaCO_3\;to\;BaTiO_3\;and\;Ba_2TiO_4$ during the thermal decomposition.

• 전자공학회논문지A
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• 제32A권2호
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• pp.19-30
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• 1995

Diffraction patterns of the copolarized and the crosspolarized total electric fields by a spherical air cavity in a dielectric medium are analyzed in the forward near-field region when the wavelength of the incident plane wave is comparable to one half of the cavity radius. It is shown that double nulls and dips of the copolarized and the crosspolarized total electric fields exist in the measurement plane tansverse to the propagating direction of the incident field, and their dependences on the frequency, the distance of the measurement plane, and the measurement angle are analyzed.

• 치위생과학회지
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• 제22권3호
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• pp.191-198
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• 2022

Background: The purpose of this study was to evaluate the composition of the crystal phases of various calcium silicate-based materials (CSMs): ProRoot white MTA^Ⓡ (mineral trioxide aggregate) (WMTA), Ortho MTA^Ⓡ (OM), Endocem MTA^Ⓡ (EM), Retro MTA^Ⓡ (RM), Endocem Zr^Ⓡ (EN-Z), Biodentine^TM (BD), EZ-seal^TM (EZ), and OrthoMTA III (OM3). Methods: In a sample holder, 5 g of the powder sample was placed and the top surface of the material was packed flat using a sterilized glass slide. The prepared slides were mounted on an X-ray diffraction (XRD) instrument (D8 Advance; Bruker AXS GmbH, Germany). The X-ray beam 2θ angle range was set at 10~90° and scanned at 1.2° per minute. The Cu X-ray source set to operate at 40 kV and 40 mA in the continuous mode. The peaks in the diffraction pattern of each sample were analyzed using the software Diffrac (version 2.1). Then, the peaks were compared and matched with those of standard materials in the corresponding Powder Diffraction File (PDF-2, JCPDS International Center for Diffraction Data). A powder samples of the materials were analyzed using XRD and the peaks in diffraction pattern were compared to the Powder Diffraction File data. Results: Eight CSMs showed a similar diffraction pattern because their main component was calcium silicate. Eight CSMs showed similar diffraction peaks because calcium silicate was their main component. Two components were observed to have been added as radiopacifiers: bismuth oxide was detected in WMTA, OM, and EM while zirconium oxide was detected in RM, EN-Z, BD, EZ, and OM3. Unusual patterns were detected for the new material, OM3, which had strong peaks at low angles. Conclusion: It was caused by the presence of Brushite, which is believed to have resulted in crystal growth in a particular direction for a specific purpose.

• 한국광학회:학술대회논문집
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• 한국광학회 1997년도 Advance Program of 14th optics andquantum Electronics conference, 1997제14 회 광학 및 양자전자 학술 발표회 논문 요약집
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• pp.80-80
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• 1997

• 한국광학회지
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• 제11권1호
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• pp.47-57
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• 2000

프란운호퍼 회절에 의하여 임의의 주어진 세기무늬를 발생시키는 연속적인 또는 양자화된 위상형 회절무늬소자를 설계하는데 hybrid input-output 알고리즘과 새로운 Pnoise 알고리즘을 결합.변형한 2단계 iterative Fourier transform 알고리즘을 이용하였다. 두 가지의 $128\times128$ 이진 세기 무늬와 두 가지의 grayscale 세기 무늬에 때하여 기존 알고리즘들과 비교하였는데, 2단계 iterative Fourier transform 알고리즘은 회절효율이 약간 낮지만 신호 대 잡음비와 특히 균일도에 있어서 우수한 결과를 보였다. 알고리즘에서 사용하는 매개변수들과 잡음영역의 크기에 따른 성능의 변화를 살펴보았고, 양자화된 위상소자의 경우 위상층수에 따른 변화도 살펴보았다. 양자화된 위상소자의 경우 세기 무늬보다는 잡음영역의 크기가 성능을 좌우하는 것으로 나타났다.

• Applied Microscopy
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• 제33권3호
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• pp.187-193
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• 2003

투과식 전자현미경에서 상과 그 회절패턴은 현미경의 자기렌즈 작용에 의하여 상오 회전되어 나타난다. 이 회전각의 측정 결정은 결정 시료의 결함 관찰 분석에서 중요하다. 이 회전각 측정에 대해 잘 알려진 방법은 $MoO_3$의 분말 결정을 이용하는 것이다. 그러나 이 방법에는 측정된 각에 항상 $180^{\circ}$의 불확실성이 따른다. 따라서 이 불확실성을 제거하기 위한 또 다른 방안이 강구되어야 한다. 본 논문에서는 결정시료의 LACBED 패턴을 얻는 과정을 통해 간단하게 이 회전각을 측정하는 새로운 방법을 제시한다. 이 방법은 특정 결정을 필요로 하지 않는다. 이 방법을 통해 JEM 2010 TEM에서 상(image)과 그 회절패턴의 회전각은 $180^{\circ}$로 측정되었고, 이 각은 확대 배율이나 카메라 길이의 변화에도 변하지 않음이 관찰되었다.

• 분석과학
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• 제5권4호
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• pp.409-415
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• 1992

$BaTiO_3$의 선구물질을 하소시키는 과정에서 얻은 X-선 회절 패턴에 인자분석법을 적용하였다. 선구물질은 수용액계에서 바륨과 티타늄의 질산염용액을 시발물질로 하여 합성하였으며 이를 여러 온도에서 하소시킨 후 X-선 회절 패턴을 얻었다. X-선 회절각에 대한 피이크세기로 구성된 데이타 매트릭스에 인자분석법을 적용시켜 3개의 인자가 존재함을 확인하였다. 3개의 인자는 $BaCO_3$, $BaTiO_3$ 및 $Ba_2TiO_4$였으며 하소온도에 따른 3가지 성분의 상대적인 농도 변화를 규명하였다.