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81.
S. Halder T. Schneller R. Waser 《Applied Physics A: Materials Science & Processing》2007,87(4):705-708
Almost all platinized substrates manufactured presently use an TiO2 adhesion layer to improve the adhesion between the SiO2 and the Pt. These substrates however are stable till only 800 °C. We show that simply by replacing the TiO2 with Al2O3, the stability of the electrodes can be increased to 1000 °C and more. These substrates can be used for high temperature
depositions which standard platinized substrates cannot withstand. Further we show that dielectric thin films of BaTiO3 and (Ba,Sr)TiO3 crystallized at higher temperatures show almost a threefold increase in permittivity on these high temperature stable platinized
silicon substrates.The large increase in permittivity is attributed to an increase in grain size at high temperatures.
PACS 61.82.Fk; 68.35.Np; 68.60.Dv; 77.55.+f; 81.20.Fw 相似文献
82.
83.
The reaction of GaMe3 and InMe3 (Me = CH3) with equimolar amounts of α-tropolone forms dimethylgallium tropolonate and dimethylindium tropolonate, respectively, in high yields. Both compounds are monomeric in solution, almost planar 7-/5-ring bicyclic structures of C2v symmetry can be discussed. According to the X-ray structure determination of Me2GaTrop (Trop = C7H5O2) this compound is dimeric in the solid state and crystallizes in the monoclinic space group P21/c with 4 formula units (2 dimers) per unit cell. Me2SnTrop2 is formed by the interaction of Me2SnCl2 with LiTrop in a molar ratio. This ditropolonate is monomeric not only in solution but also in the solid state. The compound crystallizes in the triclinic space group P (Z = 4), and the molecules have a cis-structure of approximate C2-symmetry. The vibrational and NMR spectra of all compounds were measured and are partly assigned. 相似文献
84.
Photoconductivity has been measured in well-dried poly(vinyl alcohol) (PVAl) films containing Cu2+ complexes prepared by treatment with Cu(NO3)2, CuSO4, CuCl2, and CuBr2. When the ratio [Cu2+]/[MU] ([MU] denoting the concentration of PVAl monomer residues) is greater than 0.015, illumination at the charge-transfer (UV) band produces a strong photocurrent in PVAl-CuCl2 and PVAl-CuBr2, but not in PVAl-Cu(NO3)2 or PVAl-CuSO4. Optical absorption spectra suggest that two halide ions enter the first coordination sphere in the cis configuration. The temperature dependence of ESR indicates the existence of antiferromagnetic superexchange interaction via intervening halide ions. Hence, there exists a network structure of the PVAl-CuCl2 or PVAl-CuBr2 complex. The dependence of the photocurrent on the polarity of the illuminated electrode shows that the majority of carriers are holes. Holes in the network structure produced by charge transfer from halogen to Cu2+ ions are concluded to be responsible for the photoconduction. 相似文献
85.
Masao Sumita Keizo Miyasaka Kinzo Ishikawa 《Journal of Polymer Science.Polymer Physics》1977,15(5):837-846
The melting point and the heat of fusion were measured by differential scanning calorimetry (DSC) as a function of draw ratio for linear polyethylene. Both the melting point and the heat of fusion increased with an increase in draw ratio. The plot of the heat of fusion against the melting point was approximately linear. The linear relation is explained theoretically using the assumption that the increases in the melting point and the heat of fusion are due to the orientation of the amorphous phase caused by drawing. The excess free energy of the amorphous phase derived from the orientation increases the melting point, and the amorphous phase absorbs heat for its randomization at the melting point. Hence for drawn samples having an oriented amorphous phase not only the crystal phase but also the amorphous phase contribute to the heat of fusion. 相似文献
86.
87.
88.
Generation of fluorescent adducts of malondialdehyde and amino acids: toward an understanding of lipofuscin 总被引:2,自引:0,他引:2
Chowdhury PK Halder M Choudhury PK Kraus GA Desai MJ Armstrong DW Casey TA Rasmussen MA Petrich JW 《Photochemistry and photobiology》2004,79(1):21-25
Lipofuscin is a yellow-brown, highly fluorescent pigment that undergoes an age-related progressive accumulation in animal cells, mainly in postmitotic cells. It is a heterogeneous, high-molecular weight material associated with proteins, lipids and nucleic acids. Lipofuscin is implicated in many aspects of human health, including aging, oxidative stress, macular degeneration, lipid peroxidation, atherosclerosis, dementia (Alzheimer's Disease) and diseases associated with prions. Although the fluorescent properties of lipofuscin have long been recognized, neither histologists nor chemists have yet isolated the pigments themselves or characterized their optical properties. We have prepared lipofuscinlike species by reacting malondialdehyde (MDA) with cysteine (Cys). MDA:Cys adducts 3:2 and 2:2 are two of those that have been identified among the many that were present in the reaction. Whereas previous attempts to synthesize lipofuscinlike species resulted in compounds that were either nonfluorescent or emitted principally in the blue, the MDA:Cys adducts reported in this study are not only fluorescent but also emit over a broader range. 相似文献
89.
We consider a credit risk model with two industrial sectors, where defaults of corporations would be influenced by two factors. The first factor represents the macro economic condition which would affect the default intensities of the two industrial sectors differently. The second factor reflects the influences of the past defaults of corporations against other active corporations, where such influences would affect the two industrial sectors differently. A two-layer Markov chain model is developed, where the macro economic condition is described as a birth-death process, while another Markov chain represents the stochastic characteristics of defaults with default intensities dependent on the state of the birth-death process and the number of defaults in two sectors. Although the state space of the two-layer Markov chain is huge, the fundamental absorbing process with a reasonable state space size could capture the first passage time structure of the two-layer Markov chain, thereby enabling one to evaluate the joint probability of the number of defaults in two sectors via the uniformization procedure of Keilson. This in turn enables one to value a variety of derivatives defined on the underlying credit portfolios. In this paper, we focus on a financial product called CDO, and a related option. 相似文献
90.
This article analytically describes broadband second-harmonic generation in a double-tapered gallium arsenide (GaAs) slab using total internal reflection quasi-phase matching technique. This double-tapered configuration ensures a combination of increasing and then decreasing bounce lengths which provides an extremely wide 3 dB bandwidth of 573.6 nm with a conversion efficiency of 1.929%, after considering reflection and absorption losses. Effect of varying the slab dimensions, viz., length and tapering angles, as well as the operating temperature on the performance parameters has also been incorporated in the analysis. 相似文献