• The Korean Journal of Ceramics
• /
• v.5 no.4
• /
• pp.341-347
• /
• 1999

An ambiguity on the correct room temperature structure of $Bi_5Ti_3FeO_{15}$ was resolved using a combined Rietveld refinement of neutron and X-ray diffraction. The structure of this compound has been reported to have a space group of F2mm (adopting 2-fold rotation symmetry along the c-axis) or A21am. However, our diffraction, study reveals that some reflections would violate F-centering and confirm that the belong to $A2_1$am. Out refinement with the space group of $A2_1$am converged at $R_p=6.85%, R_wp=9.23%$ and $\chi^2$=1.66 for an isotropic temperature model with 85 variables. The lattice constants are a=5.4677(1) $\AA$, b=5.4396(1) $\AA$, and c=41.2475(8)$\AA$. In structure, Ti/Fe atoms at the oxygen octahedral sites of the perovskite unit are completely disordered, resulting in that these atoms are transparent in neutron diffraction. The octahedra of the perovskite unit are relatively displaced along the a-axis against the Bi atoms, which contribute as a major component to the spontaneous polarization of $Bi_5Ti_3FeO_{15}$.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1995.06a
• /
• pp.117-118
• /
• 1995

• Proceedings of the Korean Vacuum Society Conference
• /
• 1993.02a
• /
• pp.108-108
• /
• 1993

• Proceedings of the Korean Vacuum Society Conference
• /
• 2003.08a
• /
• pp.74-74
• /
• 2003

• Proceedings of the Korean Magnestics Society Conference
• /
• 2012.11a
• /
• pp.9-9
• /
• 2012

• Journal of the Korean Chemical Society
• /
• v.29 no.4
• /
• pp.456-458
• /
• 1985

• Proceedings of the Korean Vacuum Society Conference
• /
• 2001.07a
• /
• pp.127-127
• /
• 2001

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1990.04a
• /
• pp.263-271
• /
• 1990

In this paper, we shall construct a ridge estimator in a multiple linear model with the correlated error structure. The existence of the biasing parameter satisfying the Mean Squared Error Criterion is also proved. Furthermore, we shall determine the value of shrinkage factors by the iteration method.

• Proceeding of EDISON Challenge
• /
• 2013.04a
• /
• pp.287-289
• /
• 2013

How the different thickness of thin films of black-P has an effect on its electronic band structure and structure has been studied by using SIESTA code. Although the interaction between the thin films has something to do with band reduction, it does not affect the inter-atomic distance between two nearest neighbour puckered layers.

• Applied Microscopy
• /
• v.47 no.4
• /
• pp.226-232
• /
• 2017

Electron microscopy and X-ray diffraction have together played a key role in our understanding of the molecular structure and mechanism of contraction of muscle. This review highlights the role of electron microscopy, from early insights into thick and thin filament structure by negative staining, to studies of single myosin molecule structure, and finally to recent high-resolution structures by cryo-electron microscopy. Muscle filaments are designed for movement. Their labile structures thus present challenges to obtaining near-atomic detail, which are also discussed.