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Ozay Gurtug Mustafa Halilsoy Izzet Sakalli 《General Relativity and Gravitation》2003,35(12):2159-2170
A technique is given to generate coupled scalar field solutions in colliding Einstein-Maxwell (EM) waves. By employing the Bell-Szekeres solution as seed and depending on the chosen scalar field, it is possible to construct nonsingular solutions. If the original EM solution is already singular, addition of scalar fields does not make the physics any better. In particular, scalar field solution that is transformable to spherical symmetry is plagued with singularities. 相似文献
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JPC – Journal of Planar Chromatography – Modern TLC - High-performance thin-layer chromatography plays an important role in the determination of lipid fractions. However, it requires... 相似文献
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In this study, Fe3+ ion selective N-(Rhodamine-6G)lactam-N'-acryloyl-ethylenediamine (RH6GAC) monomer was synthesized. Then, p(Acrylamide-co-N-(Rhodamine-6G)lactam-N'-acryloyl-ethylenediamine) (p(AAm-co-RH6GAC)) and p(2-hydroxyethyl- methacrylate-co- N-(Rhodamine-6G)lactam-N'-acryloyl-ethylenediamine) (p(HEMA-co-RH6GAC)) colorimetric hydrogels were synthesized by using acrylamide (AAm) and 2-hydroxyethylmethacrylate (HEMA) as primary monomers. FT-IR, SEM, polymerization yield and swelling characterizations were conducted for the resulting hydrogels. Then, these hydrogels were used in selective absorption of Fe3+ ions from aqueous media. The hydrogels, which could absorb Fe3+ ions selectively from a mixture of metal ions, were used as column packing material. The solutions containing Fe2+ and Fe3+ ions at different concentrations were separated at a rate of 97.7 ± 0.7%. 相似文献
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Sefik Suzer Ozgur Birer Adnan U. Sevil Olgun Guven 《Monatshefte für Chemie / Chemical Monthly》2001,132(1):185-192
Summary. 2-Chloro-polyaniline (2-Cl-PANI) in its non-conducting (emeraldine base, EB) form, prepared by a chemical route, was dissolved together with poly-(vinylchloride)
(PVC) in THF for casting into thin (10–50 μm) films. Upon exposure to UV radiation, the electrical conductivity of these films increased
by more than 4 orders of magnitude (from 10−6 to 10−2S/cm). This is attributed to the dehydrochlorination of PVC by exposure to energetic photons and subsequent doping of 2-Cl-PANI (i.e. conversion to emeraldine salt, ES) by in situ created HCl. The doped films could be returned to their undoped form by exposure to NH3 vapours. The UV-induced doping/NH3 undoping cycles could be repeated several times. Various spectroscopic techniques were employed to follow the changes in
the films upon exposure to UV radiation. The same photo-dehydrochlorination process has also been utilized for optical and/or
lithographic purposes by preparing PVC blends containing methyl violet, and acid-base indicator dye. The photo-dehydrochlorination can be effectively sensitized
by incorporating hydroquinone into the PVC blends containing methyl violet.
Received June 23, 2000. Accepted (revised) July 31, 2000 相似文献
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Sefik Suzer Ozgur Birer Adnan U. Sevil Olgun Guven 《Monatshefte für Chemie / Chemical Monthly》2001,100(3):185-192
2-Chloro-polyaniline (2-Cl-PANI) in its non-conducting (emeraldine base, EB) form, prepared by a chemical route, was dissolved together with poly-(vinylchloride) (PVC) in THF for casting into thin (10–50 μm) films. Upon exposure to UV radiation, the electrical conductivity of these films increased by more than 4 orders of magnitude (from 10−6 to 10−2S/cm). This is attributed to the dehydrochlorination of PVC by exposure to energetic photons and subsequent doping of 2-Cl-PANI (i.e. conversion to emeraldine salt, ES) by in situ created HCl. The doped films could be returned to their undoped form by exposure to NH3 vapours. The UV-induced doping/NH3 undoping cycles could be repeated several times. Various spectroscopic techniques were employed to follow the changes in the films upon exposure to UV radiation. The same photo-dehydrochlorination process has also been utilized for optical and/or lithographic purposes by preparing PVC blends containing methyl violet, and acid-base indicator dye. The photo-dehydrochlorination can be effectively sensitized by incorporating hydroquinone into the PVC blends containing methyl violet. 相似文献
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Kaan Atak Ozgur O. Aybar Gokhan ?ahin Avadis Hac?nl?yan Yani Skarlatos 《Central European Journal of Physics》2009,7(3):568-574
Polyethylene Glycol has an irregular current characteristic under constant voltage and slowly varying relative humidity. The
current through a thin film of Gamma-isocyanatopropyltriethoxysilane added Polyethylene glycol (PEG-Si), its hydrogenated
and hydrophobically modified forms, as a function of increasing relative humidity at equal time steps is analyzed for chaoticity.
We suggest that the irregular behavior of current through PEG-Si thin films as a function of increasing relative humidity
could best be analyzed for chaoticity using both time series analysis and detrended uctuation analysis; the relative humidity
is kept as a slowly varying parameter. The presence of more then one regime is suggested by the calculation of the maximal
Lyapunov exponents. Furthermore, the maximal Lyapunov exponent in each of the regimes was positive, thus confirming the presence
of low dimensional chaos. DFA also confirms the presence of at least two different regimes, in agreement with the behavior
of the maximal Lyapunov exponent in the time series analysis. We also suggest that the irregular behavior of the current through
PEG-Si can be reduced by hydrogenating and hydrophobically modifying PEG-Si and the improvement in stability can be confirmed
by our study.
相似文献
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Adsorption behavior of linear and cyclic genetically engineered platinum binding peptides 总被引:4,自引:0,他引:4
Seker UO Wilson B Dincer S Kim IW Oren EE Evans JS Tamerler C Sarikaya M 《Langmuir : the ACS journal of surfaces and colloids》2007,23(15):7895-7900
Recently, phage and cell-surface display libraries have been adapted for genetically selecting short peptides for a variety of inorganic materials. Despite the enormous number of inorganic-binding peptides reported and their bionanotechnological utility as synthesizers and molecular linkers, there is still a limited understanding of molecular mechanisms of peptide recognition of and binding to solid materials. As part of our goal of genetically designing these peptides, understanding the binding kinetics and thermodynamics, and using the peptides as molecular erectors, in this report we discuss molecular structural constraints imposed upon the quantitative binding characteristics of peptides with an affinity for inorganics. Specifically, we use a high-affinity seven amino acid Pt-binding sequence, PTSTGQA, as we reported in earlier studies and build two constructs: one is a Cys-Cys constrained "loop" sequence (CPTSTGQAC) that mimics the domain used in the pIII tail sequence of the phage library construction, and the second is the linear form, a septapeptide, without the loop. Both sequences were analyzed for their adsorption behavior on Pt thin films by surface plasmon resonance (SPR) spectroscopy and for their conformational properties by circular dichroism (CD). We find that the cyclic peptide of the integral Pt-binding sequence possesses single or 1:1 Langmuir adsorption behavior and displays equilibrium and adsorption rate constants that are significantly larger than those obtained for the linear form. Conversely, the linear form exhibits biexponential Langmuir isotherm behavior with slower and weaker binding. Furthermore, the structure of the cyclic version was found to adopt a random coil molecular conformation, whereas the linear version adopts a polyproline type II conformation in equilibrium with the random coil. The 2,2,2-trifluoroethanol titration experiments indicate that TFE has a different effect on the secondary structures of the linear and cyclic versions of the Pt binding sequence. We conclude that the presence of the Cys-Cys restraint affects both the conformation and binding behavior of the integral Pt-binding septapeptide sequence and that the presence or absence of constraints could be used to tune the adsorption and structural features of inorganic binding peptide sequences. 相似文献