• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.235-236
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• 2002

A Klystron powered dual photon energy electron linear accelerator 2300 C/D from Varian Associates has been installed in our center. From the radiological safety view as well as treatment planning, the output (contamination) of Bremsstrahlung Radiation with electron beam energy determined accurately. It has been found 0.5% to 4.7% with increasing the electron beam energy which is the clinically not much significant in the treatment of the malignant diseases with the treatment of electron beam.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.3
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• pp.198-205
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• 2006

The necessity of nondestructively inspecting austenitic steels, fiber-reinforced composites, and other inherently anisotropic materials has stimulated considerable interest in developing beam models for anisotropic media. The properties of slowness surface playa key role in the beam models based on the paraxial approximation. In this paper, we apply a modular multi-Gaussian beam (MMGB) model to study the effects of material anisotropy on ultrasonic beam profile. It is shown that the anisotropic effects of beam skew and excess beam divergence enter into the MMGB model through parameters defining the slope and curvature of the slowness surface. The overall beam profile is found when the quasilongitudinal(qL) beam propagates in the symmetry plane of transversely isotropic austenitic steels. Simulation results are presented to illustrate the effects of these parameters on ultrasonic beam diffraction and beam skew. The MMGB calculations are also checked by comparing the anisotropy factor and beam skew angle with other analytical solutions.

• Journal of architectural history
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• v.16 no.3
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• pp.21-38
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• 2007

If we take account of the 'Architectural Tradition' which aims a construction of better environment, we can see that this tradition has ended historically toward Utopia. It is a continual trend from ancient Greece to contemporary epoch in each transitional periods and especially in the Renaissance Era. Utopia is an ideal commonwealth in which inhabitants exist under perfect conditions, ideally perfect places or state of things. The plans of utopia are complete projects of image, its goal is an social, political and economical improvement according to the eras. Its plans are characterized by rigid geometrical pattern as circle and square, which contain generally center axis symmetry enclosure. Recent urban and architectural circumstances no longer reflect utopian visions. Since the latter of the 20th century, it appears dystopia on the contrary. Therefore, the utopian ideal city and architecture describes characteristics of the era unlike the continuity of its concept.

• Transactions on Electrical and Electronic Materials
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• v.18 no.6
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• pp.320-322
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• 2017

In this paper, a high-performance, low-area gradient-magnitude calculator architecture is proposed, based on approximate image processing. To reduce the computational complexity of the gradient-magnitude calculation, vector properties, the symmetry axis, and common terms were applied in a hardware-resource-shared architec-ture. The proposed gradient-magnitude calculator was implemented using an Altera Cyclone IV FPGA (EP4CE115F29) and the Quartus II v.16 device software. It satisfied the output-data quality while reducing the logic elements by 23% and the embedded multipliers by 76%, compared with previous work.

• Korean Institute of Interior Design Journal
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• no.41
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• pp.29-35
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• 2003

The purpose of this study is to analyze the architectural manifesto and design works characteristics of Walter Gropius. He was the director of Weimar Bauhaus that one of the advanced artificial movements in the early modern period. The almost of the early modern movements was related to the radical ideology and the manifesto. Especially Bauhaus originated from manifesto of artists teaching group with architect Walter Gropius. Therefore, the category of the study pitch upon Bauhaus architectural manifesto - Bauhaus Manifesto and Programme(1919) - and the representative works of Walter Gropius - Fagus Factory(1911-14), Dessau Bauhaus Building(1925-26), Siedlung Berlin-Siemensstadt(1929-30) and Harvard Graduate Center(1949). The conclusions of the study as per the above mentioned pill pose are the dynamic integration by non-symmetry in cubic form (formal characteristics) and organic continuity by reciprocality in transparent space (spatial characteristics).

• Progress in Superconductivity
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• v.3 no.2
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• pp.146-150
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• 2002

We performed the point contact spectroscopy on newly discovered superconductor $MgB_2$ thin films with Au tip. In the point contact spectroscopy of the metallic Sharvin limit, the differential conductance below the gap is twice as that above the gap by virtue of Andreev Reflection. After some surface cleaning processes of sample preparation such as ion-milling and wet etching, the obtained dI/dV versus voltage curves are relatively well fitted to the Blonder-Tinkham-Klapwijk (BTK) formalism. Gaps determined by this technique were distributed in the range of 3meV~ 8meV with the BCS value of 5.9meV in the weak coupling limit. We attribute these discrepancies to the symmetry of the gap parameter and the degradation of the surface of the sample. We also present the temperature dependence of the conductance vs voltage curve and thereby the temperature dependence of the gap.

• Transactions of Materials Processing
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• v.22 no.6
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• pp.328-333
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• 2013

The current study aims to determine the limit strains more accurately and reasonably when producing a forming limit curve (FLC) from experiments. The international standard ISO 12004-2 in its recent version (2008) states that the limit major strain should be determined by using the best-fit inverse second-order parabola through the experimental strain distribution. However, in cases where fracture does not occur at the center of the specimen, due to insufficient lubrication, the inverse parabola does not give a realistic fit because of its intrinsic symmetry in shape. In this study it is demonstrated that an inverse quartic function can give a much better fit than an inverse parabola in almost all FLC test samples showing asymmetric strain distributions. Using a quartic fit creates more reliable FLCs.

• Korean Journal of Crystallography
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• v.11 no.2
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• pp.84-88
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• 2000

The crystal of cholesteryl crotylcarbonate was investigated by X-ray diffraction method. Crystallographic data for the title compound: P21, a=13.510(2)Å, b=11.843(2)Å, c=19.882(2)Å, β=106.88(1)°, Z=4. Reflections were collected with an Enraf-Nonius CAD-4 diffractometer equipped with a graphite monochromator. The structure was solved by direct methods and refined by least-squares analyses. The final R value was 0.125 for 2607 reflections. The cholesterol fragment of the title compound were in good agreement with those for related cholesterol derivatives. The molecules were stacked in clearly separated layers. At the center of the layers, there were cholesteryl-cholesteryl interactions between the symmetry-related B molecules and the cholesteryl-C(17) side chain of A molecules. There were also interactions between the C(17) side chain of B molecules and the crotylcarbonate chain in the interface region between layers. The crystal structure of the title compound turned out to be isostructural with those of cholesteryl ethylcarbonate and cholesteryl propylcarbonate.

• Journal of the Chungcheong Mathematical Society
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• v.31 no.1
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• pp.137-149
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• 2018

In this paper, under the assumption of the symmetry point spread function, antireflective boundary conditions(AR-BCs) are considered in connection with the fast truncated Lagrange(FTL) method. The FTL method is proposed as an image restoration method for large-scale ill-conditioned BTTB(block Toeplitz with Toeplitz block) and BTHHTB(block Toeplitz-plus-Hankel matrix with Toeplitz-plus-Hankel blocks) linear systems([13, 17]). The implementation and efficiency of the FTL method in the AR-BCs are further illustrated. Especially, by employing the AR-BCs, both the continuity of the image and the continuity of its normal derivative are preserved at the boundary. A reconstructed image with less artifacts at the boundary is obtained as a result.

• Journal of the Korean Chemical Society
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• v.14 no.1
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• pp.123-126
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• 1970

The approximate crystal structure of benzidine monoperchlorate has been determined by single crystal X-Ray diffraction technique and patterson method. As the molecule has a center of symmetry in it and location of perchlorate ion is symmetrically on the mirror plane in the unit cell, perchlorate ion is forming hydrogen bond with two -$NH_2$ groups in the different molecule. Thus, one molecule of benzidine and perchloric acid combines 1:1 by mole ratio.