Abstract: Laser post-heating computer controlled detonation spraying (CCDS) and cold spray (CS) hybrid processes were proposed for fabrication of near sub micron structure coatings of hydroxyapatite (HA) + Ti system. Optical and SEM with energy dispersive X-ray analysis and comparative XRD phase analysis were used to evaluate microstructure. After those hybrid processes, no substantial variation in HA composition was noted by structural and phase examination. Nano-sized HA powders can be recommended for laser annealing CS (LaCS) process. Regimes of laser treatment optimal for increasing the adhesion between the HA and titanium coatings, providing more strength, ductility and decreasing of HA destruction in the coatings were determined.
Crystals2015, 5(4), 433-446; doi:10.3390/cryst5040433 - published 24 September 2015 Show/Hide Abstract
Abstract: The new ternary arsenides AE3TrAs3 (AE = Sr, Ba; Tr = Al, Ga) and their phosphide analogs Sr3GaP3 and Ba3AlP3 have been prepared by reactions of the respective elements at high temperatures. Single-crystal X-ray diffraction studies reveal that Sr3AlAs3 and Ba3AlAs3 adopt the Ba3AlSb3-type structure (Pearson symbol oC56, space group Cmce, Z = 8). This structure is also realized for Sr3GaP3 and Ba3AlP3. The compounds Sr3GaAs3 and Ba3GaAs3 crystallize with the Ba3GaSb3-type structure (Pearson symbol oP56, space group Pnma, Z = 8). Both structures are made up of isolated pairs of edge-shared AlPn4 and GaPn4 tetrahedra (Pn = pnictogen, i.e., P or As), separated by the alkaline-earth Sr2+ and Ba2+ cations. In both cases, there are no homoatomic bonds, hence, regardless of the slightly different atomic arrangements, both structures can be rationalized as valence-precise [AE2+]3[Tr3+][Pn3−]3, or rather [AE2+]6[Tr2Pn6]12−, i.e., as Zintl phases.
Crystals2015, 5(4), 418-432; doi:10.3390/cryst5040418 - published 24 September 2015 Show/Hide Abstract
Abstract: Several nitrogen-rich salts of 3-nitramino-4-nitrofurazane and dinitraminoazoxyfurazane were synthesized and characterized by various spectroscopic methods. The crystal structures were determined by low temperature single crystal X-ray diffraction. Moreover the sensitivities toward thermal and mechanical stimuli were determined by differential thermal analysis (DTA) and BAM (Bundesanstalt für Materialforschung und -prüfung) methods. The standard enthalpies of formation were calculated for all compounds at the CBS-4M level of theory, and the energetic performance was predicted with the EXPLO5 V6.02 computer code.
Crystals2015, 5(3), 405-417; doi:10.3390/cryst5030405 - published 18 September 2015 Show/Hide Abstract
Abstract: Two new potentially energetic salts comprising the 5,5'-azotetrazolate dianion have been prepared and structurally characterized. The new azotetrazolates are tetraphenylphosphonium-5,5'-azotetrazolate (1) and 1H-1,2,4-triazole-1-carboxamidine-5,5'-azotetrazolate (2). The crystal structures of both compounds have been determined by single-crystal X-ray diffraction and their energetic properties have been tested. Due to its high nitrogen-content of 73.14%, compound 2 was found to be significantly impact-sensitive.
Crystals2015, 5(3), 394-404; doi:10.3390/cryst5030394 - published 14 September 2015 Show/Hide Abstract
Abstract: Polarization characteristics of defect mode peaks in a one-dimensional (1D) photonic crystal (PC) with a nematic liquid crystal (NLC) defect layer have been investigated. Two different polarized defect modes are observed in a stop band. One group of defect modes is polarized along the long molecular axis of the NLC, whereas another group is polarized along its short axis. Polarizations of the defect modes can be tuned by field-induced in-plane reorientation of the NLC in the defect layer. The polarization properties of the 1D PC with the NLC defect layer is also investigated by the finite difference time domain (FDTD) simulation.
Crystals2015, 5(3), 376-393; doi:10.3390/cryst5030376 - published 10 September 2015 Show/Hide Abstract
Abstract: Three cyano-1-(phenylsulfonyl)indole derivatives, 3-cyano-1-(phenylsulfonyl) indole, (I), 2-cyano-1-(phenylsulfonyl)indole, (II), and 2,3-dicyano-1-(phenylsulfonyl) indole, (III), and a key synthetic precursor 1-(phenylsulfonyl)-1-(1,1-dimethylethyl) indole-3-carboxamide, (IV), have been synthesized and their structures determined by single crystal X-ray crystallography. (I), C15H10N2O2S, is orthorhombic with space group P 212121 and cell constants: a = 4.9459(3) Å, b = 10.5401(7) Å, c = 25.0813(14) Å, V = 1307.50(14) Å3 and Z = 4. (II), C15H10N2O2S, is monoclinic with space group C 2/c and cell constants: a = 18.062(2) Å, b = 11.293(2) Å, c = 15.922(3) Å, α = 90°, β = 124.49(2)°, g = 90°, V = 2676.7 Å3 and Z = 8. (III), C16H9N3O2S, is triclinic with space group P-1 and cell constants: a = 8.1986(8) Å, b = 9.6381(11) Å, c = 9.8113(5) Å, α = 95.053(6)°, β = 101.441(6)°, g = 108.071(9)°, V = 713.02(11) Å3 and Z = 2. (IV), C19H20N2O3S, is orthorhombic with space group P ccn and cell constants: a = 13.7605(8) Å, b = 27.3177(14) Å, c = 9.7584(6) Å, α = 90°, β = 90°, g =90°, V = 3668.2(4) Å3 and Z = 8. All four compounds have the same indole nitrogen phenylsulfonyl substituent and (I), (II), and (III) are nitrile derivatives. (IV) is a tert-butylamide. In the crystals, the dihedral angle between the mean planes of the indole and phenylsulfonyl groups are 85.4(2)° (I), 87.2(7)° (II), 75.1(7)° (III), and 88.6(2)° (IV), respectively. Additionally, DFT geometry-optimized molecular orbital calculations were performed and frontier molecular orbitals of each compound are displayed. Correlation between the calculated molecular orbital energies (eV) for the surfaces of the frontier molecular orbitals to the electronic excitation transitions from the absorption spectra of each compound has been proposed.