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Abstract Mit Einkristall‐Röntgenbeugungsmethoden wurde an Ba 6 Dy 2 Al 4 O 15 ein neuer Strukturtyp gefunden. Es kristallisiert orthorhombisch, Raumgruppe D –Cmcm, a = 5,898; b = 10,183; c = 14,877 Å, Z = 2. Den Aufbau dieser Verbindung bestimmt ein BaO‐Gerüst mit einer 8+1‐Sauerstoffkoordination um Ba 2+ , ferner eck…
The absorption spectra and fluorescence spectra of La 1-x Nd x P 5 O 14 (LNPP) glass were studied. The fluorescence from the level of interest 4 F 3/2 (1) state shows an exponential decay and linear concentration quenching. Time resolved fluorescence line narrowing was observed for LNPP glass with different x values.…
A combined method based on the finite-difference method (FDM) and the charge-simulation method (CSM) is proposed for electric field calculation. In this method, the entire field is divided into two domains, which are analyzed separately with FDM and CSM. These domains are coupled together using the continuity conditio…
Phase diagrams of chiral nematic liquid crystals are studied within the framework of a generalized Landau-Ginzburg-de Gennes theory. Using the parametrization of Grebel, Hornreich, and Shtrikman for the tensor order parameter Q, all relevant elastic terms are included for the helicoidal phase and the blue phases of ch…
Three chemical precleaning methods suitable for aluminum alloy vacuum chambers for electron storage rings have been compared. The methods ranged from vapor degreasing with no chemical attack to light alkaline etching and strong alkaline etching in NaOH. The techniques used to evaluate and compare the three treatments…
The hydrolysis reaction of a 1:1 mixture of LFeCl3 and LMnCl3(L =N,N′N″-trimethyl-1,4,7-triazacyclononane) in aqueous sodium acetate solution yields green [LFeIII(µ-O)(µ-MeCO2)2MnIIIL]2+(90%) which displays strong intramolecular antiferromagnetic exchange coupling (J=–145 cm–1) yielding a doublet ground state; an e.s.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic states and potential energy surfaces of silver dihydride: comparison with gold dihydrideK. Balasubramanian and M. Z. LiaoCite this: J. Phys. Chem. 1989, 93, 1, 89–94Publication Date (Print):January 1, 1989Publication History Published online1 May 2002Published ini…
The thermal expansion of both the cathode and interconnect of the high temperature solid oxide fuel cell is reviewed. The influence of dopants such as Al, Mg and Sr are discussed. Data are presented which suggest that Sr doped LaCrO 3 matches the thermal expansion of zirconia best, but this composition is more suscept…
Experiments were made of the synthesis of AlN by reduction of Al2O3 with graphite powder in flowing N2 atmosphere at various temperatures between 1773 and 1973 K. At temperature below 1823 K, a temporary rise in the reaction rate was observed near the reaction degree of 50%. This discontinuous change was reflected in…
A procedure is proposed to study and identify the model of a buried permanent-magnet synchronous motor which takes account of the nonlinear magnetic phenomena caused by the armature current. The experiment procedures are described, and the results of the measurement of the parameters of the linear d-q model of the mot…
Measurements of tracer diffusion coefficients D of Fe-59, Ni-63 and Cr-51, in zirconium single crystals and of Fe-59 in some zirconium alloys have been made. The single crystal measurements were made in directions both parallel Dǁ and perpendicular D⊥ to the c axis of the specimens; results for nickel were obtained at…
The dense wustite plates containing CaO together with SiO2 and/or Al2O3 have been reduced isothermally in a stream of hydrogen at temperatures between 670 and 930°C.Reduction rate of the specimens added CaO together with SiO2 or Al2O3, increases monotonously along with the increase of CaO addition at temperatures belo…
Infrared absorption spectra of hydroxyl stretching vibrations in soda germanate glasses were measured over the range from ambient temperature up to about their softening point. The spectrum of 5Na 2 O · 95GeO 2 glass was found to consist of two absorption bands through an analysis of the spectral changes with temperat…
The unusual solid state dimerisation of β-nitrostyrene to yield two isomeric cyclobutanes is accounted for by its disordered, photoreactive crystal structure which permits a trans→cis isomerisation.
Abstract Neu dargestellt wurden die Oxide RbLiZnO 2 (A) und RbLiZn 2 O 3 (B) in Form farbloser Einkristalle durch Tempern entsprechender Gemenge der binären Oxide. Beide Zincate kristallisieren tetragonal, A: Raumgr. I4/mmm, Z = 2, a = 351,84(4), c = 1153,3(2) pm; B: Raumgr. P4 2 /mnm, Z = 4, a = 1 033,8(1), c = 342,8…
ESR spectra are reported for frozen CH2Cl2/ClCH2CH2Cl solutions of 14 low-spin manganese(II) cations: [(η5-C5H5)Mn(CO)L2]+, L = 1/2 Ph2PCH2CH2PPh2(dppe), 1/2 Me2PCH2CH2PMe2(dmpe), 1/2 Ph2PCH2PPh2(dppm), PMe3, PPh3; [(η5-MeC5H4)Mn(CO)dppe]+; [(η5-6-exo-PhC6H6)Mn(CO)L2]+, L = 1/2 dppe, 1/2 dmpe, PMe3; [(η5-6-exo-PhC6HMe…
Analysis of the various models for the local field shows that most of them give similar Lorenz—Lorentz formulae for nematic liquid crystals. They differ only in the way they define parameters such as the structural anisotropy. Because of the arbitrariness of the model parameters, the structural anisotropy values in th…
The crystal structures of the complexes [Co(OH2)5][Cu(cdta)]·H2O (5), [Zn(OH2)4][Zn(cdta)(OH2)]·4H2O (6), and [Zn0.7Co0.3(OH2)4][Zn0.3Co0.7(cdta)(OH2)]·4H2O (7)(cdta =trans-cyclohexane-1,2-diamine-NNN′N′-tetra-acetate) have been determined by X-ray methods. They crystallize in space groups Pbc21, P21/n, and P21/n resp…
The effect of oxides and oxide glasses on the oxidation of AlN powder and substrate was studied by thermogravimetric analysis, supplemented by XRD, optical microscopy, and EPMA. The oxidation behavior of powder mixtures of AlN and oxides or glass frits in air was dependent on the oxide species. Oxides were divided int…
Water vapor transport through rigid polyurethane and polyisocyanurate foams was investigated using three test methods—two under isothermal conditions and one in the presence of a thermal gradient. All three methods yielded water vapor transmission coefficients of the materials. It is observed that the magnitude of the…