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Z. Z. Öztürk E. Musluoğlu V. Ahsen A. Gül Ö. Bekaroğlu 《Journal of Materials Science》1992,27(22):6183-6186
D.c. conductivities of polycrystalline monoazacrown ether-substituted phthalocyanines (M=2H, Ni, Zn, Pb, Cu) and diphthalocyanine (M=Lu) are measured as Au-MPc-Au sandwiches to be of the order 10–10–10–12 S m–1. Chemical doping with oxidants (e.g. NOBF4) and enhancing the stacking of planar phthalocyanine moieties through the formation of alkali metal adducts with sodium and potassium ions leads to increase in conductivity of the order 101–102. The low conductivity and the diamagneticity of the bis(phthalocyaninato)-lutetium can be ascribed to the lack of radical nature in LuH(Pc)2. For the a.c. conductivities, lead and lutetium complexes form a group with higher conductivities and the rest show lower conductivity. The conduction activation energies calculated from Arrhenius plots exhibit the lowest value (0.40 eV) for the lutetium compound.Part of this work was presented at NATO-ASI on Semiconductor Materials and Processing Technologies, Erice, Sicily, 1–13 July 1991. 相似文献
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T. Basova E. Kol'tsov A.G. Gürek D. Atilla V. Ahsen A.K. Hassan 《Materials science & engineering. C, Materials for biological applications》2008,28(2):303-308
The mesogenic properties of copper octakisalkylthiophthalocyanine [(C6S)8PcCu] were studied by differential scanning calorimetry (DSC), X-ray and optical microscopy. This phthalocyanine forms columnar hexagonal (Colh) mesophase. Thin films of (C6S)8PcCu were prepared by spin-coating technique. Thermally induced molecular reorganization within the films was studied by the methods of ellipsometry and UV–Vis absorption spectroscopy. Heat treatment produces molecular ordering which is believed to be due to stacking interaction between neighbouring phthalocyanine moieties. The differences in structural organization of the heated and unheated films were stated. These differences in structural organization in their turn are found to influence the electrical properties of the films. 相似文献
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Ferhat Bülbül Hikmet Altun ?zkan Kü?ük Vefa Ezirmik 《Metals and Materials International》2012,18(4):631-637
This study aims to evaluate the tribological and corrosion properties of the electroless Ni-B coating deposited on AISI 304 stainless steels. The microstructure of the coating was characterized using x-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS). XRD analysis revealed that the prepared coating possessed an amorphous character. SEM-EDS investigation also indicated that a non-stoichiometric Ni-B coating was deposited with a columnar growth mechanism on the stainless steel substrate and the morphology of the growth surface was blackberry-like. The hardness and tribological properties were characterized by microhardness and a pin-on-disc wear test. The electroless Ni-B coated sample had a higher degree of hardness, a lower friction coefficient and a lower wear rate than the uncoated substrate. The electrochemical potentiodynamic polarization method was used to evaluate the corrosion resistance of the coating. The electroless Ni-B coating offered cathodic protection on the substrate by acting as a sacrificial anode although it was electrochemically more reactive than the stainless steel substrate. 相似文献
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Sezen Tekin H. Gul Yaglioglu Ayhan Elmali Ulaş Kürüm Hülya Yanık Duygu Aydın Tekdaş Mahmut Durmuş Vefa Ahsen 《Materials Chemistry and Physics》2013
The nonlinear optical properties (NLO) of Pcs can be modified by substituting different metal atoms into the ring or altering peripheral and axial functionalities. In this study, nonlinear optical absorption properties of tetra-substituted gallium and indium phthalocyanine complexes both in solution and polymeric film have been investigated by open aperture Z-scan measurements with nanosecond pulses at 532 nm. All investigated compounds exhibited reverse saturable absorption for both solution and film experiments. The investigated compounds in the solution showed better nonlinear optical absorption properties than polymeric films. The observed nonlinear optical absorption differences depending on the aggregation are discussed using the ultrafast dynamics and decay processes of excited states found from femtosecond pump-probe spectroscopy with white light continuum experiments. 相似文献
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Giuntini F Dumoulin F Daly R Ahsen V Scanlan EM Lavado AS Aylott JW Rosser GA Beeby A Boyle RW 《Nanoscale》2012,4(6):2034-2045
Polyacrylamide nanoparticles bearing two orthogonal reactive functionalities were prepared by reverse microemulsion polymerisation. Water-soluble photosensitisers and peptide or carbohydrate moieties were sequentially attached to the new nanospecies by orthogonal conjugations based on copper-catalysed azide-alkyne cycloaddition and isothiocyanate chemistry. 相似文献
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U. Cevik N. Damla R. Van Grieken M. Vefa Akpınar 《Construction and Building Materials》2011,25(4):1546-1552
The main goal of this work was to determine the chemical composition of building materials used in Turkey by utilizing energy dispersive X-ray fluorescence (EDXRF) spectrometry. Gas concrete, cement, sand, bricks, roofing tiles, marble, lime and gypsum materials were selected as building materials for this research. The chemical contents and their trace concentrations of the selected samples were determined. The most abundant oxides measured were generally SiO2, Al2O3, CaO, MgO, Fe2O3, K2O and SO3 for all samples. While the main chemical component of gas concrete, cement, sand and marble samples were SiO2 and CaO, brick and roofing tile mainly consisted of SiO2 and Al2O3. CaO and SO3 were major component of lime and gypsum samples, respectively. For U and Th concentrations in the samples, activities of 226Ra and 232Th were measured by utilizing gamma spectrometry. ANOVA and Pearson correlation analyses were performed on the studied data for statistical analysis. 相似文献
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Tugrul Cetinkaya Ahsen Akbulut Mehmet O. Guler Hatem Akbulut 《Journal of Applied Electrochemistry》2014,44(2):209-214
A flexible lithium manganese oxide (LiMn2O4)/multi-wall carbon nanotube (MWCNT) composite electrode was produced by casting a slurry-containing powdered LiMn2O4 on a previously prepared MWCNT paper. The structure of this new LiMn2O4/MWCNT composite electrode was characterized using scanning electron microscopy and X-ray diffraction patterns. Furthermore, the surfaces of these electrodes were coated with gold–palladium alloy using an RF magnetron sputtering technique to prevent Mn dissolution. To investigate the electrochemical performance of this flexible LiMn2O4/MWCNT composite electrode, a bare-LiMn2O4 electrode was prepared. The discharge capacity of the produced LiMn2O4/MWCNT nanocomposite electrode was cyclically tested, and the charge transfer resistance of the electrodes was studied using electrochemical impedance spectroscopy. Consequently, the Au–Pd-coated LiMn2O4/MWCNT had a 120 mAh g?1 discharge capacity and 90 % capacity retention after 100 cycles. 相似文献
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Effect of Cement on Emulsified Asphalt Mixtures 总被引:5,自引:0,他引:5
Seref Oruc Fazil Celik M. Vefa Akpinar 《Journal of Materials Engineering and Performance》2007,16(5):578-583
Emulsified asphalt mixtures have environmental, economical, and logistical advantages over hot mixtures. However, they have
attracted little attention as structural layers due to their inadequate performance and susceptibility to early life damage
by rainfall. The objective of this article is to provide an improved insight into how the mechanical properties of emulsion
mixtures may be improved and to determine the influence of cement on emulsified asphalt mixtures. Laboratory tests on strength,
temperature susceptibility, water damage, creep and permanent deformation were implemented to evaluate the mechanical properties
of emulsified asphalt mixtures. The test results showed that mechanical properties of emulsified asphalt mixtures have significantly
improved with Portland cement addition. This experimental study suggested that cement modified asphalt emulsion mixtures might
be an alternate way of a structural layer material in pavement. 相似文献