• Applied Microscopy
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• 제21권1호
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• pp.108-120
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• 1991

Principles of electron diffraction patterns in transmission electron microscope are described for beginners in terms of reciprocal lattices and Ewald sphere. Analysis of both ring patterns and spot patterns are illustrated with practical examples as well as basic calibrations of TEM. Especially convergent beam electron diffraction method is emphasized for the determination of lattice parameters, microstrains, and thickness of thin foil followed by a review of microcomputer programs for the electron diffraction analyses explained in this paper.

• Journal of the Optical Society of Korea
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• 제4권1호
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• pp.7-10
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• 2000

The soft x-ray(10nm-100nm) interferometer is a modified Mach-Zehnder type interferometer and it consists of two beam-splitters and four totally reflecting mirrors. The beam-splitters used here are 50% transmission and 50% reflection grating type. The diffraction patterns of beam splitters(1st B.S.) were investigated with a He-Ne laser. The diffraction patterns produced by the soft x-ray interferometer (2nd B.S.) were also investigated in intensities positions. The diffraction patterns of 20 degree grazing incidence on the beam splitters(1st B.S.) show a circular array of spots. Both the reflected and the transmitted beams show the same patterns but symmetric circles on the screen. The maximum intensity appears roughly when n is in the zeroth and odd orders and the suppressed peak(missing order) appears when n is in even orders. Intensities of 3 center fringes(n = 0, $\pm$1) are stronger than others. These results confirm the reduced grating equation and make agree with the intensity distribution function. It was found that the final patterns produced by the soft x-ray interferometer (2nd B.S.) consisted of fine fringes which were caused by two of three diffraction beams that were arrived at the second beam-splitter.

• Applied Microscopy
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• 제32권3호
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• pp.185-193
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• 2002

Texture electron diffraction pattern을 이용한 결정구조 해석 이론은 러시아어로 씌여졌거나, 영문판 저서의 일부에 간단히 소개 되어있어 이해에 어려움이 있다. 이들의 이론은 벡터의 이론과 관련된 여러 관계식을 이용해서 설명될 수 있으며, 이로서 몇 개의 식에 포함된 오류를 수정하였다.

• Journal of Magnetics
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• 제5권2호
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• pp.27-34
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• 2000

The structure of a series of Cu/Ni is characterized by using a program, SUPREX, to model the x-ray diffraction patterns, multilayers. The samples had nominal layer thickness of 3/3, 7/7, 13.5/13.5, 20/20, 30/30, 50/50, 80/80, 100/100, and 200/200 Angstroms. The diffraction patterns were taken around the (111) peak for the two constituent materials. A kinematical model is used to characterize the diffraction patterns and the parameters for the model are described. An initial model is calculated using initial guesses for the parameters. The model is then fit to the data by reducing $x^2$using the Levenberg-Marquardt algorithm. The samples are shown to be high quality supperlattices.

• 한국세라믹학회지
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• 제35권10호
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• pp.1113-1119
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• 1998

Crystal structure of needle-shaped maghemite(${\gamma}$-{{{{ { {Fe }_{2 }O }_{3 } }}) has been studied by the Rieveld analysis of powder X-ray diffraction patterns. The tetragonal space group P41,.3212 and cubic space group P41,.32 have been have been used for the refinement of X-ray diffraction patterns. The crystal system of maghemite is closed to tetragonal more than cubic. The tetragonal lattice parameters are a=8.3460$\AA$ and c=25.034$\AA$ The standard X-ray diffraction pattern of the tetragonal maghemite analyzed with space group P41,.3212 is proposed.

• 약학회지
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• 제8권2호
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• pp.37-44
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• 1964

The relationships involving acid-consuming capacity and X-ray powder diffraction patterns of aluminum hydroxide gel were studied. The aging of antacid efficacy of aluminum hydroxide gel has also been characterized by using X-ray powder diffraction. The acid-consuming capacity decreased with progress of crystallization from amorphous alumino gel, and it was found that aged product at 80.deg. C had crystal structure of bohmite (.alpha.-Al.sub 2/O$_{2}$(OH)$_{2}$). It was also noted that the rate of aging decreased with decreasing pH of aluminum hydroxide gel.

• Journal of electromagnetic engineering and science
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• 제18권3호
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• pp.175-181
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• 2018

The array patterns of a patch array antenna were calculated using an active element pattern (AEP) method that considers ground edge effects. The classical equivalent radiation model of the patch antenna, which is characterized by two radiating slots, was adopted, and the AEPs that include mutual coupling were precisely calculated using full-wave simulated S-parameters. To improve the accuracy of the calculation, the edge diffraction of a ground plane was incorporated into AEP using the uniform geometrical theory of diffraction. The array patterns were then calculated on the basis of the computed AEPs. The array patterns obtained through the conventional AEP approach and the AEP method that takes ground edge effects into account were compared with the findings derived through full-wave simulations conducted using a High Frequency Structure Simulator (HFSS) and FEKO software. Results showed that the array patterns calculated using the proposed AEP method are more accurate than those derived using the conventional AEP technique, especially under a small number of array elements or under increased steering angles.

• 한국전기전자재료학회논문지
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• 제21권9호
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• pp.829-834
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• 2008

Two-dimensional photonic quasicrystal (PQCs) template patterns have been fabricated on a 1.1 ${\mu}m$-thick DMI-150 photoresist using a multiple-exposure holographic method. A 442-nm HeCd laser was utilized as a light source and the holographic exposure was carried out at a fixed angle of ${\theta}$ = 6$^{\circ}$. After the first holographic exposure, the sample was rotated to a proper angle and the second exposure was performed to the same manner. This exposure process was repeated n/2 times to obtain n-fold symmetric PQC patterns and then the sample was developed. The diffraction patterns of the fabricated PQC template were observed using a 632.8-nm HeNe laser. The fabricated PQCs exhibited 8, 10 and 12-fold rotational symmetry, which was in a good agreement with the interference simulation results. In addition, the diffraction patterns with n-rotation symmetry were observed for the corresponding n-fold PQCs. We believe that the multiple-exposure holography is a good method to fabricate the mesoscale PQCs with a high rotational symmetry.

• 한국광물학회지
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• 제17권2호
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• pp.177-187
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• 2004

Au 내부 표준시편을 이용하여 일반 전자회절도형에서도 알바이트와 올리고클레이스의 격자 상수 값을 1% 이내의 오차범위로 얻었다. 자연산 올리고클레이스 시료의 전자회절도형 지도를 작성하였고, 11개 지점의 정대축 전자회절도형을 얻었다 이러한 작업은 삼사정계민 장석으로부터 신뢰성 있는 전자현미경 연구 결과를 얻기 위해서는 필수적인 과정이다. 장식의 {001} 벽개면과 TEM의 양측경사 시료지지대를 이용하면 장석의 구조/화학 분석에 필요한 다음과 같은 정보를 획득할 수 있다: 알칼리 장석은 [001] 방향에서 ＊ 값을, [100] 방향에서 $\alpha$＊ 값을 측정하여 $\alpha$＊ - ＊ plot을 함으로써 미세 영역에서 Si-Al ordering 상태 및 화학 조성을 예측할 수 있다. Na-rich한 사장석은 [001] 방향에서 ＊ 값을 측정하여 Si-Al ordering 상태를 예측할 수 있다. Na-poor한 사장석은 [100] 방향에서 e-reflection의 유무, 회절강도 및 위치 변화를 측정하여 구조 및 화학을 예측할 수 있다.

• 한국환경보건학회지
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• 제29권4호
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• pp.48-54
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• 2003

This study investigated retrogradation properties of Jeungpyun substituted for cereals with dietary fibers of 60% of brown rice, and barley. Quality changes during storage periods of the functional Jeungpyun, were studied using $\alpha$-amylase iodine enzyme digestion methods, X-ray diffraction patterns, and differential scanning calorimetry (DSC). The barley substituted samples showed significantly lower retrogrdation rates than those of control when examined by $\alpha$-amylase method. The Relative crystallity by X-ray diffraction patterns had typical A type in all samples with appealing big crystallity around its diffraction angle 23$^{\circ}$degrees as storage periods were increased. The brown rice and barley Jeunpyun made smaller crystallity than that of control, representing slower retrogradation rates. The batter controls had significantly lower ΔH than the other compared samples when measured by DSC, but had significantly higher ΔH after 30 days of storage, implying that the control required more energy for regelatinization after the 30 days of storage.