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61.
A new derivate of 4-bromo-1,8-naphthalic anhydride and its quaternized analogue have been prepared and characterized. The interactions of both derivatives with human telomere quadruplex-DNA and ds-DNA have been comparatively studied by UV-visible (UV-Vis), fluorescent intercalator displacement assays, competition dialysis, circular dichroism (CD), agarose gel electrophoresis, and polyacrylamide gel electrophoresis. The results show that both derivatives can stabilize G-quadruplexes DNA, and they show different binding affinities for G-quadruplexes-DNA and ds-DNA. All spectroscopic studies have shown that the derivatives have a modest selectivity for G-quadruplex versus ds-DNA. 相似文献
62.
A new Au(III)-imprinted hydrogel (Au(III)-Imp) was prepared by the photopolymerisation of 4-acryloylmorpholine (AcM), 2-hydroxyethyl acrylate (HEA), and poly(ethylene glycol) diacrylate (cross-linking monomer, PEG-DA) in the presence of gold ions. In addition, non-imprinted hydrogel (N-Imp) was similarly prepared without Au(III) ions The Au(III)-Imp hydrogel was characterised by several techniques. To achieve the optimal conditions, effect of pH, time, and initial metal ion concentrations were investigated using a batch system. The pre-concentration factor for Au(III) ions was found to be at least 100. The analytical parameters of the method were determined and the method was also successfully applied to computer circuit board scrap samples. The reusability of the Au(III)-Imp hydrogel was also determined. 相似文献
63.
The main object of this paper is to present a systematic investigation of new classes of quaternion numbers associated with the familiar Pell and Pell-Lucas numbers. The various results obtained here for these classes of quaternion numbers include recurrence relations, summation formulas and Binet’s formulas. 相似文献
64.
Pinar Sinem Omurtag Ufuk Saim Gunay Aydan Dag Hakan Durmaz Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2013,51(10):2252-2259
The Diels‐Alder reaction as a click reaction strategy is applied to the preparation of well‐defined polycarbonate (PC)‐block copolymers. A well‐defined α‐anthracene‐terminated polycarbonate (PC‐anthracene) is prepared using 9‐anthracene methanol as an initiator in the ring opening polymerization of benzyl 5‐methyl‐2‐oxo‐1,3‐dioxane‐5‐carboxylate in CH2Cl2 at room temperature for 5 h. Next, a well‐defined α‐furan protected maleimide‐terminated‐poly(ethylene glycol) (PEG11‐MI or PEG37‐MI), ‐poly(methyl methacrylate) (PMMA26‐MI), and ‐poly(ε‐caprolactone) (PCL27‐MI) were clicked with the PC‐anthracene at reflux temperature of toluene to yield their corresponding PC‐based block copolymers (PC‐b‐PEG, PC‐b‐PMMA, and PC‐b‐PCL). The homopolymer precursors and their block copolymers were characterized by using the GPC, NMR and UV analysis. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
65.
Bayram Can Cumhur Canbazoğlu Nesli Albayrak Nilgün Çelebi Mahmut Doğru 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(3):1059-1063
The fact that 50% of the natural radiation dose to which humans are exposed is caused by radon gas makes indoor radon measurements important. In this study, levels of indoor radon gas were measured in 204 houses in Kilis, Osmaniye and Antakya using passive nuclear track detectors. Cr-39 radon detectors were left in the living rooms of participants’ houses, then analyzed at the Radon Laboratory of Health Physics Department in Çekmece Nuclear Research and Training Center (ÇANEM) of Atomic Energy Agency of Turkey (TAEK). Average indoor radon activity concentrations for Kilis, Osmaniye and Antakya were 50 Bq/m3 (1.26 mSv/y), 51 Bq/m3 (1.29 mSv/y) and 40 Bq/m3 (1.01 mSv/y), respectively. 相似文献
66.
This paper provides a two-stage decision framework in which two or more parties exercise a jointly held real option. We show that a single party’s timing decision is always socially efficient if it precedes bargaining on the terms of sharing. However, if the sharing rule is agreed before the exercise timing decision is made, then socially optimal timing is attained only if there is a cash payment element in the division of surplus. If the party that chooses the exercise timing can divert value from the project, then the first-best outcome may not be possible at all and the second-best outcome may be implemented using a contract that is generally not optimal in the former cases. Our framework contributes to the understanding of a range of empirical regularities in corporate and entrepreneurial finance. 相似文献
67.
Mehmet Çopuroğlu Lee Huat Kelly Koh Shane O’Brien Gabriel M. Crean 《Journal of Sol-Gel Science and Technology》2009,52(3):432-438
Zinc oxide thin films were prepared using either zinc acetate dihydrate or anhydrous zinc acetate via the sol–gel method.
Comparative characterisation of the crystallographical, morphological, optical/spectroscopical and electrical properties of
the so-obtained films was performed. The idea of one- (in the case of the anhydrous precursor), and two- (in the other case)
stage hydrolysis/condensation was postulated, which was supported by the characterisation results. The film prepared using
the anhydrous precursor had a more pronounced c-axis crystal orientation preference, with a larger average crystallite size and more porous morphology. The transparency
of this film was significantly lower over the UV/visible region due to its more porous morphology, which also resulted in
lower intensity of the ‘near band edge emission’, and higher electrical resistivity. The overall results also suggested that
anhydrous zinc acetate could be employed as a precursor for the sol–gel synthesis of zinc oxide thin films, which might have
potential advantages in microelectronic and optoelectronic applications. 相似文献
68.
Ahmet Bilgin Çiğdem Yağcı Ayşegül Mendi Ufuk Yıldız 《Journal of inclusion phenomena and macrocyclic chemistry》2010,67(3-4):377-383
Synthesis of metal-free and metallophthalocyanines bearing α-methylferrocenylmethoxy units was described. Precursor 3 required for the preparation of phthalocyanines 4–9, was synthsized by the nucleophilic aromatic substitution reaction between α-methylferrocenylmethanol and 4-nitrophthalonitrile in dry DMF. The metal-free phthalocyanine 4 was prepared from 4-(α-methylferrocenylmethoxy)phthalonitrile 3 in 1-pentanol with a catalytic amount of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Metallophthalocyanines (M = Zn, Cu, Co, Ni and Pb) were prepared by cyclotetramerization reaction of phthalonitrile with appropriate materials. The phthalonitrile, metal-free and metallophthalocyanines were characterized by 1H and 13C NMR, FT-IR UV–Vis and mass spectral data, as well as elemental analyses, which were consistent with the proposed structures. 相似文献
69.
Nadir Kiraz Ömer Kesmez Esin Burunkaya Leyla Budama Burçin Acar Meltem Asiltürk H. Erdem Çamurlu Ertuğrul Arpaç 《Journal of Sol-Gel Science and Technology》2010,56(3):227-235
This paper describes the preparation and characterization of glass films consisting of SiO2, Li2O, Na2O, K2O or MgO in varying compositions on stainless steel and aluminum substrates by sol–gel method. Silver phosphate or silver
incorporated zeolite was also introduced into the sols for obtaining antibacterial effect. The SiO2/Li2O/Na2O system having the composition of 85:5:10 wt% was found as the optimum for obtaining a stable sol and film formation. The
films were investigated by scanning electron microscopy (SEM) and electron dispersive analysis by X-ray (EDX), Fourier transformed
infrared (FTIR) spectroscopy, thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA). Homogenous films
having 300 ± 20 nm thicknesses were formed by spin coating and then by curing at 500 °C for 1 h. Obtained films had high adherence
to the metal substrates and they were also durable in acidic, basic or NaCl environments. They also presented a powerful antibacterial
effect against E. coli. 相似文献
70.
Stable polymeric and colloidal boehmite sols were prepared by sol–gel process through controlled hydrolysis/condensation reactions.
The particle sizes of the colloidal sols were in the 12–25 nm range depending on the process parameters and about 2 nm for
polymeric sols. The presence of a significant increase in the microporosity content of the heat treated polymeric membranes
relative to the mesoporous colloidal membranes might make the design of thermally stable microporous alumina membranes with
controlled pore structures possible. The phase structure evolution in the 600–800 °C range had shown that the crystallization
of the gamma alumina in the amorphous matrix starts at about 800 °C. This indicated that the pore structure stability may
be enhanced through processing up to this relatively high temperature in polymeric alumina derived unsupported membranes.
The permeance values of the two and three layered colloidal alumina membranes were observed to be independent of pressure
which implies that the dominant gas transport mechanism is Knudsen diffusion in these structures. This was also supported
by the 2.8 nm BJH pore sizes of the colloidal membranes. The Knudsen diffusion equation derived permeances of the polymeric
alumina membranes with thicknesses of about 300 nm were determined to be very close to the experimentally determined permeance
values. 相似文献