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41.
Oriňák Andrej Vering Guido Arlinghaus Heinrich F. Andersson Jan T. Halas Ladislav Oriňáková Renáta Turčániová Ľudmila 《平面色谱法杂志一现代薄层色谱法》2005,18(1):44-50
JPC – Journal of Planar Chromatography – Modern TLC - A new hyphenated technique that enables coupling of thin-layer chromatography (TLC) with time-of-flight secondary-ion mass... 相似文献
42.
Renáta Oriňáková Hans-Dieter Wiemhöfer Jürgen Paulsdorf Veronika Barinková Anna Bednáriková Roger M. Smith 《Journal of Solid State Electrochemistry》2006,10(7):458-464
The electrochemical impedance method was applied during the electrochemical deposition of a binary Ni–Co coating on iron powder in a fluidised bed electrode system. The influence of the suspension density on the charge transfer in the course of the electro-deposition process was studied. At a potential of −900 mV (vs. Ag/AgCl/3 M KCl), when the binary Ni–Co layer was formed, the impedance data were characterised by two semicircles with the semicircle at high frequencies being larger in magnitude. A contribution of the diffusion process to the overall current was observed. The optimal suspension density for the charge transfer in the bed was 10×10−3–15×10−3 (i.e., 4–6 g of iron powder in 50 ml of electrolyte). The most probable mechanism of the charge transfer for the studied concentrations of powder particles is the convective mechanism. The iron particles dispersed in the electrolyte were considered to act as either a depolariser or an additional working electrode depending on the applied electrode potential and on the suspension density. 相似文献
43.
J. Orbán Sz. Halasi G. Papp Szilvia Barkó Beáta Bugyi 《Journal of Thermal Analysis and Calorimetry》2005,82(1):287-290
Summary The thermodynamic properties of the cardiac and skeletal a-actin isoforms were studied to characterize the molecular bases
of the functional differences between them with the method of differential scanning calorimetry (DSC). The thermal properties
of the actin filaments were described in the presence of calcium and magnesium ions as well. Based on the calculated free
energy changes the α-cardiac actin filaments appeared to be more stable in its physiologically more relevant, magnesium saturated
form. The magnesium saturated form of the α-cardiac actin filaments seemed to be more stable compared to the calcium saturated
form of it. The enthalpy and entropy changes could differentiate between the α-cardiac and α-skeletal actin isoforms and between
the calcium and magnesium saturated cardiac actin isoforms as well. Our results can demonstrate that the few differences between
the amino acid sequences of the α-actin isoforms have an influence on the thermal properties and maybe on the function of
these proteins as well. 相似文献
44.
4-(4′-Dioctylaminocarbonylbiphenyloxy) phthalonitrile was synthesized from 4-(4′-carboxybiphenyloxy)phthalonitrile and dioctylamine
in the presence of Et3N. Metallophthalocyanines (Zn, Co and Cu) substituted with four dioctylaminocarbonyl biphenyloxy groups on the peripheral
positions were prepared from 4-(4′-dioctylaminocarbonylbiphenyloxy)phthalonitrile and the corresponding divalent metal salts
(Zn(CH3COO)2, CoCl2 and CuCl2). The new phthalocyanines are soluble in common organic solvents. These compounds were characterised by 1H-NMR, 13C-NMR, FT-IR, UV-Vis and mass spectroscopies. 相似文献
45.
Vlastimil Matějec Ivan Kašík Daniela Berková Miloš Hayer Jiří Kaňka 《Journal of Sol-Gel Science and Technology》1998,13(1-3):617-621
Optical cores of preforms for drawing optical fibers doped with Er3+ and Yb3+ were fabricated by the sol-gel method with the aim of increasing the thickness of glass layers coated in a single coating cycle and to determine the relation between the preparation conditions and optical properties of the fibers. Al2O3-P2O5-SiO2 and TiO2-P2O5-SiO2 glasses have been studied as matrices for entrapping the rare-earth elements. Input sols have been prepared from silicon and titanium alkoxides, AlCl3, ErCl3, YbCl3, POCl3, water and a modifier under acidic catalysis of HCl. The sols were coated on the inner wall of a silica substrate tube and the gel layers were sintered at high temperatures up to 2000°C after which the tube was collapsed into the preform. Continuous and homogenous glass films with the maximum thickness of about 8 m were fabricated. The influence of high-temperature heat treatment of the layers on their composition and optical attenuation was observed. The amplified stimulated emission of Er3+ around 1.55 m was measured under the excitation of the fibers by an Nd : YAG laser at 1.064 m. 相似文献
46.
A new liquid chromatographic (LC)-chemometric approach was developed for the determination of sunset yellow (SUN) and tartrazine (TAR) in commercial preparations. This approach uses LC and chemometric calibration methods, i.e., classical least-squares (CLS), principal component regression (PCR), and partial-least squares (PLS), simultaneously. The combined LC-chemometric approaches, denoted as LC-CLS, LC-PCR, and LC-PLS, are based on photodiode array (PDA) detection at multiple wavelengths. Optimum chromatographic separation of SUN and TAR with allura red as the internal standard (IS) was obtained by using a Waters Symmetry C18 column, 5 microm, 4.6 x 250 mm, and 0.2 M acetate buffer (pH 5)-acetonitrile-methano-bidistilled water (55 + 20 + 15 + 10, v/v) as the mobile phase at a flow rate of 1.9 mL/min. The LC data sets consisting of the ratios of analyte peak areas to the IS peak area were obtained by using PDA detection at 5 wavelengths (465, 470, 475, 480, and 485 nm). LC-chemometric calibrations for SUN and TAR were separately constructed by using the relationship between the peak-area ratio and the training sets for each colorant. LC-chemometric approaches were tested for different synthetic mixtures containing SUN and TAR in the presence of the IS. These LC-chemometric calibrations were applied to a commercial preparation of the 2 colorants. The experimental results of the LC-chemometric approaches were compared with those obtained by a developed classical LC method using single-wavelength detection. 相似文献
47.
48.
Ka Young Lee 《Tetrahedron letters》2004,45(26):5043-5046
The reaction of arylacetylenes 1 and N,N-dimethylformamide dimethylacetal (2a, DMF-DMA) afforded the corresponding arylpropargyl aldehydes 3 in moderate yields. Similarly, the reaction of 1 and N,N-dimethylacetamide dimethylacetal (2b, DMA-DMA) gave 4-aryl-3-butyn-2-ones 4. 相似文献
49.
The 1,10-phenanthroline (phen) complexes of Co(II), Ni(II), Cu(II) and
Cd(II) orotates were synthesized and characterized by elemental analysis,
magnetic susceptibility, spectral methods (UV-vis and FTIR) and thermal analysis
techniques (TG, DTG and DTA). The Co(II), Ni(II), Cu(II) and Cd(II) ions in
diaquabis(1,10-phenanthroline)metal(II) diorotate octahedral complexes [M(H2O)2(phen)2](H2Or)2·nH2O
(M=Co(II), n=2.25; Ni(II), n=3;
Cu(II) and Cd(II), n=2) are coordinated
by two aqua ligands and two moles of phen molecules as chelating ligands through
their two nitrogen atoms. The monoanionic orotate behaves as a counter ion
in the complexes. On the basis of the first DTGmax,
the thermal stability of the hydrated complexes follows the order: Cd(II),
68°C 68°C 相似文献
50.
N. K. Tunali H. N. Erten S. Kinikoğlu Ş. Gümüş 《Journal of Radioanalytical and Nuclear Chemistry》1979,49(2):225-237
The extraction of iodine and bromine under various conditions from their saturated aqueous solutions by CCl4, C6H6 and o-xylene has been studied. The data obtained from the experiments carried out at various temperatures, for H2O(I2)−CCl4 and H2O(I2)−C6H6 systems, exhibit an Arrhenius behaviour. The overall activation energy calculated for the extraction in the H2O(I2)−CCl4 system, 650±50 cal·mol−1 is lower than that of H2O(I2)−C6H6, 3600±300 cal·mol−1. The use of the solubility parameter for the interpretation of the data in the extraction of iodine is investigated. The
data obtained in multiple extractions are treated by using the analogy between extraction and radioactive decay. The half
number of extraction for each system is determined. The complex curves obtained in the H2O(I2)−CCl4 and H2O(I2) −Br2)−CCl4 systems are resolved into two components. 相似文献