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  • 1
    Electronic Resource
    Electronic Resource
    Determination of ordinary refractive index profile for a planar waveguide by transmission spectrum analysis (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 5650-5657 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We introduce a new method to determine the ordinary refractive index profile of a planar waveguide on a crystal plate. The index profile of the planar waveguide can be numerically divided into multilayers; the transmission spectrum of the multilayer waveguide can be calculated and numerically analyzed to fit the measured transmission spectrum. We demonstrated this method on a proton exchanged planar waveguide in z-cut LiTaO3. We found that the ordinary refractive index profile of this waveguide can very well be described by a Fermi–Dirac function. The index profile evolution with proton exchange time and anneal time were obtained together with the diffusion coefficients for the proton exchange and anneal processes. We discovered that, for the proton exchange process in LiTaO3, there exists a surface diffusion phenomenon which has a much smaller diffusion coefficient than that of the bulk diffusion. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.367418
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  • 2
    Electronic Resource
    Electronic Resource
    Cordierite gels from TEOS and aluminum and magnesium nitrates under basic conditions (1995)
    Springer
    Journal of sol gel science and technology 5 (1995), S. 41-47 
    Details
    ISSN: 1573-4846
    Keywords: cordierite ; basic hydrolysis ; crystallisation ; sinterability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Synthesis of cordierite gels was performed using Si(OC2H5)4 and aluminum and magnesium nitrates as starting materials under basic conditions. Further heat treatment yields the successive crystallisation of μ and α-cordierites and of some amounts of spinel as a secondary phase as revealed by X-ray diffraction. The poor final densification (84% of the theoretical value) of samples obtained from the as-prepared powders has been improved by ball-milling to values up to 95–98% of the theoretical value, the spinel proportion being simultaneously decreased.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00486709
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  • 3
    Electronic Resource
    Electronic Resource
    Carnitine Contents in Remnant Liver, Kidney, and Skeletal Muscle after Partial Hepatectomy in Rats: Randomized Trial (1998)
    Springer
    World journal of surgery 22 (1998), S. 42-47 
    Details
    ISSN: 1432-2323
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Carnitine, an important carrier of free fatty acid that is transported into mitochondria for beta-oxidation, was thought to be one of the key factors in the regulation of liver regeneration. If the carnitine content is insufficient in the hepatocyte, it might impair the energy substrate’s transport and the energy charge required for cell regeneration. The purpose of this study is to evaluate the changes of carnitine content in remnant liver, kidney, and skeletal muscle simultaneously after partial hepatectomy in rats. Partial hepatectomy with resection of the median and left lateral lobes was performed on male Wistar rats. Rats with a sham operation comprised a control group. This study was an experimental randomized trial. Ten rats from each group were sacrificed before the operation and at 6, 24, 48, and 72 hours after the operation. The carnitine content, as total and free forms, in remnant liver, kidney, and skeletal muscle were quantified by high-performance liquid chromatography. The carnitine contents in the remnant liver increased significantly at 6, 24, and 48 hours after partial hepatectomy ( p 〈 0.01). The increase of total carnitine content was more obvious than that of the free form. In contrast, the decreasing concentrations of total carnitine and free carnitine in the kidney were significant ( p 〈 0.01). In skeletal muscle the total carnitine content decreased to a small extent, and it was observed only at 6 hours after partial hepatectomy ( p 〈 0.05). It is suggested that remnant liver promoted the generation of carnitine, whereas kidney and skeletal muscle released their stored carnitine at an early stage after partial hepatectomy. As a result, the influx of the carnitine into hepatocytes increased at the regenerative stage. The carnitine content of remnant liver is sufficient during the early posthepatectomy stage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002689900347
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  • 4
    Electronic Resource
    Electronic Resource
    Crystal Structure and Properties of a New Copper(II) Complex of Dioxocyclam Appended with 8-Methylquinoline (Dioxocyclam = 1,4,8,11-tetraazacyclotetradecane-5,7-dione) (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 27 (1997), S. 245-258 
    Details
    ISSN: 1573-1111
    Keywords: Crystal structure ; properties ; new copper(II) complex ; dioxocyclam ; 8-methylquinoline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new macrocyclic dioxotetraamine ligand 1-(quinolin-8-ylmethyl)-1,4,8,11-tetraazacyclotetradecane-5,7-dione (H2L) has been synthesized. The resulting dioxocyclam readily forms a 1 : 1 Cu(II) complex (CuL) with concomitant double deprotonation of the ligand. CuL has been isolated as single crystals and the structure was determined by X-ray diffraction analysis. CuL·5H2O (1·5H2O) crystallizes in monoclinic crystal system, P21/n space group with a = 12.979(2), b = 13.638(6), c = 13.634(4) Å, β = 103.02(2)°, V = 2351(2) Å3, Mr = 521.07, Z = 4, Dcalc = 1.472 g/cm3, μ = 9.78 cm-1, F(000) = 1100, room temperature, and R = 0.039, Rw = 0.042 for 2137 observed reflections with I 〉 3σ(I). In complex 1, the Cu atom is five coordinate to form a distorted square pyramid in which N(5) of the quinoline pendant is at the apical site. The Cu—N(5) bond distance (2.262(4) Å) is longer than the basal average Cu—N bond lengths (1.994(4) ring;). The behavior of CuL in solution has been studied further with ESR, UV-Vis and cyclic voltammetry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007944920831
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  • 5
    Electronic Resource
    Electronic Resource
    Preparation and properties of C60-containing poly(vinyl alcohol) (1997)
    Springer
    Journal of polymer research 4 (1997), S. 17-24 
    Details
    ISSN: 1572-8935
    Keywords: Buckminsterfullerene C60 ; Poly(vinyl alcohol) ; Cyclic voltammetry ; Redox feasibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Poly(vinyl alcohol) (PVA) was reacted with strong base NaH to yield pendant oxy anions, followed with nucleophilic addition to C60. The resulted PVA(C60-Na+)n products were then converted to PVA(C60H)n by stirring with a strong acid cation exchanger of H+-form. Extraction of the C60-containing PVAs by toluene, which is a good solvent for C60, exhibits no color transfer to the toluene phase. The C60-containing PVAs were identified by the characteristic IR and UV-Vis absorptions of C60. The electrochemical behaviors in solution or in film state were investigated by cyclic voltammetric methods. The cyclic voltammogram of 4a shows a reduction peak at −2.30 V which should be due to the bonded C60 chromophores. In the film state, obtained by coating C60-containing PVA solution on graphite electrode, PVA(C60-Na+)n is much easily reduced and oxidized than PVA(C60H)n. Furthermore, the difference in this reduction and oxidation feasibility is enhanced with increasing C60 content. However, coating with PVA(C60H)n or PVA(C60-Na+)n reduces the redox ability of the graphite electrode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0003-5
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  • 6
    Electronic Resource
    Electronic Resource
    Delineation of potential seismic sources for seismic zoning of Iran (1999)
    Springer
    Journal of seismology 3 (1999), S. 17-30 
    Details
    ISSN: 1573-157X
    Keywords: potential seismic source ; seismic hazard assessment ; seismogenic zone ; seismotectonic province ; tectonic analogy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A total of 235 potential seismic sources in Iran and neighboring regions are delineated based on available geological, geophysical, tectonic and earthquake data for seismic hazard assessment of the country. In practice, two key assumptions are considered; first, the assumption of earthquake repeatedness, implying that major earthquakes occur preferentially near the sites of previous earthquakes; second, the assumption of tectonic analogy, which implies that structures of analogous tectonic setting are capable of generating same size earthquakes. A two-step procedure is applied for delineation of seismic sources: first, demarcation of seismotectonic provinces; second, determination of potential seismic sources. Preferentially, potential seismic sources are modeled as area sources, in which the configuration of each source zone is controlled, mainly, by the extent of active faults, the mechanism of earthquake faultings and the seismogenic part of the crust.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009737719013
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis, crystal structure and properties of the nickel(II) complex of a new dioxocyclam bearing 2-methylfuran pendants (1997)
    Springer
    Transition metal chemistry 22 (1997), S. 1-3 
    Details
    ISSN: 1572-901X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new dioxocyclam ligand, bearing two 2-methylfuran pendants, has been synthesized and its nickel(II) complex isolated as a single crystal. The crystal structure of the complex has been determined by X-ray diffraction analysis. The complex adopts an unusual cis-configuration. The square-planar N4 coordination of the four basal nitrogen atoms with Ni II is evident, with the dioxocyclam moiety composed of two tertiary amine Ns and two deprotonated amide N; s; the latter nitrogens have stronger coordination bonds than those in the tertiary amines. There is a hydrogen bond between O(1) and a water molecule [O(1) H2O = 2.698]. The solution behaviour of NiL (1) has been further studied by u.v.-vis. and cyclic voltammetric techniques. A remarkable red-shift was observed for the maxima absorption band of the electronic spectra of NiL (1) in comparison to that of NiL 0 (H2L0, dioxocyclam = 1,4,8,11-tetraazacyclo-tetradecane-5,7-dione).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018581214840
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  • 8
    Electronic Resource
    Electronic Resource
    Synthesis, magnetism and crystal structure of a chloride-bridged binuclear nickel(II) complex of tris(2-pyridylmethyl)amine (1996)
    Springer
    Transition metal chemistry 21 (1996), S. 235-237 
    Details
    ISSN: 1572-901X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new binuclear NiII complex, [{(TPA)Ni(μ-Cl)}2]-(ClO4)2·H2O (1), where TPA = tris(2-pyridyl-methyl) amine, has been prepared and characterized. The X-ray crystal structure and variable temperature magnetic susceptibility (4–300 K) of the complex have been determined. The two NiII atoms of (1) are in a distorted octahedral environment and are bridged by Cl atoms. Ni-Cl distances are 2.363(6) and 2.503(7) Å, and the Ni-Cl-Ni angle is 92.7(2)°. The metal atoms are separated by a non-bonding distance of 3.523 Å. The effective magnetic moment of (1) increases slightly with decreasing temperature and appears to reach a maximum before decreasing. The observed data were fitted to the Heisenberg model and the results indicate that there is a ferromagnetic interaction (positive J) and weak antiferromagnetic intermolecular interaction (negative θ).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00165974
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  • 9
    Electronic Resource
    Electronic Resource
    New 1,4,8,11-tetraazacyclotetradecane-5,7-dione ligands appended with additional 2-methylthiophene(s) pendant: crystal structure and properties of their copper(II) complexes (1997)
    Springer
    Transition metal chemistry 22 (1997), S. 479-482 
    Details
    ISSN: 1572-901X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two new macrocyclic dioxotetraamine ligands, 1-(2-methylthiophene)-1,4,8,11-tetraazacyclotetradecane-5,7-dione (H2L1) and 1,11-bis(2-methylthiophene)-1,4,8,11-tetraazacyclotetradecane-5,7-dione (H2L2), have been synthesized and characterized. The resulting dioxocyclams readily coordinate to CuII. The CuII complex of H2L2 has been isolated as a single crystal and the structure determined by X-ray diffraction analysis. The copper atom is in a square-planar environment with four basal nitrogen atoms. The solution behaviour of the CuII complexes, CuL1 and CuL2, has been further studied by e.s.r., u.v.–vis. and cyclic voltammetric techniques. A remarkable redshift has been observed for the maximum absorption band in the electronic spectra of CuL1 or CuL2 compared with that of the unsubstituted copper species (CuL). Electrochemical studies suggest that the introduction of thiophene pendant(s) to the macrocycle destabilizes the CuIII ion compared with the unsubstituted dioxocyclam, and the reason for this is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018511313081
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  • 10
    Electronic Resource
    Electronic Resource
    High Power Characterization of Piezoelectric Materials (1998)
    Springer
    Journal of electroceramics 2 (1998), S. 33-40 
    Details
    ISSN: 1573-8663
    Keywords: high power ; piezoelectric ; resonance/antiresonance ; pulse drive method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Three techniques for measuring high voltage/power piezoelectric properties, which have been developed recently, are compared: a voltage-constant piezoelectric resonance method, a current-constant piezoelectric resonance method, and a pulse drive method. The conventional resonance method with a constant voltage circuit exhibits significant distortion (or a hysteresis) in the resonance frequency spectrum under a high vibration level due to large elastic non-linearity, which limits precise determination of the electromechanical coupling parameters. To the contrary, the resonance method with a constant current circuit (i.e., constant velocity) can determine the coupling parameters more precisely from a perfectly-symmetrical resonance spectrum. The general problem in both resonance methods is heat generation in the sample during the measurement. In order to separate the temperature characteristic from the non-linearity, it is recommended that the pulse method be used in parallel, even though the accuracy is not very high.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009962925948
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