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Simulation of band gap structures of 1D photonic crystal
R. L. Wang,J. Zhang,Q. F. Hu 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.-
We present a simple way to fabricate polyethylene methacrylate (PMMA) 1D periodic structures at the nanometer scale by using the calibrating sign of a digital scanning-electron microscope (SEM), and the transmission spectrum of a 1D photonic crystal consisting of PMMA layers and air layers with different incident angles of light was calculated by the transfer matrix method thus giving the photonic band- gap structures. It is found that the 1D photonic crystal appears to have a similar band gap structure both in TE and in TM mode, and the photonic band gap expands and the center wavelength of the forbidden bands blue-shifts with increasing incident angle of the light. This suggests that the larger the thickness of the medium layers forming the photonic crystal, the wider the photonic band gaps will be. We present a simple way to fabricate polyethylene methacrylate (PMMA) 1D periodic structures at the nanometer scale by using the calibrating sign of a digital scanning-electron microscope (SEM), and the transmission spectrum of a 1D photonic crystal consisting of PMMA layers and air layers with different incident angles of light was calculated by the transfer matrix method thus giving the photonic band- gap structures. It is found that the 1D photonic crystal appears to have a similar band gap structure both in TE and in TM mode, and the photonic band gap expands and the center wavelength of the forbidden bands blue-shifts with increasing incident angle of the light. This suggests that the larger the thickness of the medium layers forming the photonic crystal, the wider the photonic band gaps will be.
Kim, Hyojin,Park, Jimin,Kim, Suwon,Shin, Dong Hae Elsevier 2018 Biochimica et biophysica acta. Proteins and proteo Vol.1866 No.3
<P>The Gram-negative bacterium Yersinia pseudotuberculosis is the causative agent of yersiniosis. D-glycero-alpha-D-manno-heptose-1-phosphate guanylyltransferase (HddC) is the fourth enzyme of the GDP-D-glycero-alpha-D-mannoheptose biosynthesis pathway which is important for the virulence of the microorganism. Therefore, HddC is a potential target of antibiotics against yersiniosis. In this study, HddC from the synthesized HddC gene of Y. pseudotuberculosis has been expressed, purified, crystallized. Synchrotron X-ray data from a selenomethionine-substituted HddC crystal were also collected and its structure was determined at 2.0 angstrom resolution. Structure analyses revealed that it belongs to the glycosyltransferase A type superfamily members with the signature motif GXGXR for nucleotide binding. Despite of remarkable structural similarity, HddC uses GTP for catalysis instead of CTP and UTP which are used for other major family members, cytidylyltransferase and uridylyltransferase, respectively. We suggest that EXXPLGTGGA and L(S/A/G)X(S/G) motifs are probably essential to bind with GTP and a FSFE motif with substrate.</P>
Structural and Optical Properties of Cd1-xCoxGa2Se4 (0.0 ≤ x ≤ 1.0) Mixed Crystals
김창대 한국진공학회 2019 Applied Science and Convergence Technology Vol.28 No.2
0.0 ≤ x ≤ 1.0 by measuring the X-ray diffraction and optical absorption. The X-ray diffraction analysis demonstrated that Cd1-xCoxGa2Se4 crystalized into a tetragonal structure for 0.0 ≤ x ≤ 1.0. The tetragonal lattice constants were a = 5.744 Å and c = 10.784 Å for CdGa2Se4 (x = 0.0), and a = 5.611 Å and c = 10.913 Å for CoGa2Se4 (x = 1.0), which are the end members of the Cd1-xCoxGa2Se4 system, exhibiting a composition dependence that varied linearly with composition x. The tetragonal structural properties of Cd1-xCoxGa2Se4 were investigated by taking into account the compositional dependence of the tetragonal distortion, 2-(c/a), and bonding distances RCd(Co)-Se and RGa-Se. The optical absorption spectra exhibited triplet absorption bands in the range 650 - 900 nm corresponding to the 4A2(4F) → 4 T1(4P) transition of the Co2+ ions with Td symmetry sites, and a broad band in the range 1100 - 2200 nm corresponding to the 4A2(4F) → 4T1(4F) transition, for all investigated compositions. The composition dependencies of the crystal-field parameter, Dq, and Racah parameter, B, are discussed on the basis of a tetrahedral crystal-field approximation and composition dependent tetragonal structure.
아연(2)-와 니켈(2)-diphenate 착물의 합성과 일차원 결정 구조
홍진아 ( Jin A Hong ),구본권 ( Bon Kweon Koo ) 대구가톨릭대학교 자연과학연구소 2011 자연과학연구논문집 Vol.9 No.1
Two 1D complexes, [Zn (dpa) (H2O)]n (1) and [Ni (dpa)(H2O)4]n (2) (dpa = dephenate) have been synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single crystal X-ray diffraction. The X-ray analysis reveals that the 1D networks of 1 and 2 are metal (II) complexes bridged by dpadianions, respectively. The zinc ions in 1 exhibit a tetrahedral geometry, while the nickel ions in 2 exhibita six-coordinated octahedral coordination environment. In each complex, thedpa ligand is coordinated to metal ions as a bis-monodentate and monodentate for 1 and bis-monodentatefashionfor 2, respectively.
Broad bandgaps of 1-D photonic crystals realized by defect structures
M. D. Huang,Y. H. Lu,이주열,이영백,Q. Xu,P. Zhang 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.-
One-dimensional photonic crystals, consisting of a stratified periodic structure and another stratified structure with contained defect layers, have been investigated. It is found that the photonic band gaps of this combined structure can be greatly broadened when it is well designed. The defect-mode range within the band gap caused by the defect layers can be compensated by the photonic band gap of a superposed photonic crystal that has a perfectly periodic structure. Thus, a broad band gap is obtained, characterized by a high level of reflectance. Widened omni-directional band gaps can also be realized by this method.