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51.
The phase of the composition CaBaLaCu2FeO7.5 is synthesized from the previously obtained CaCuO2, La2Cu2O5, and BaFeO2 double oxides enriched up to 14.7% in 57Fe. The phase has the orthorhombic crystal system with the unit cell parameters as follows: a = 0.3882(3) nm, b = 0.3911(3) nm, c = 1.1823(8) nm. Based on the M?sbauer spectra analysis, the conclusion is drawn that iron atoms occupy only Cu(1) sites in
the lattice, while more than 90% of them are in the Fe4+ valence state (80% of these atoms have the tetragonal pyramidal coordination). 相似文献
52.
Sázelová P Kasicka V Koval D Kilár F Knopp D Peltre G 《Journal of chromatography. A》2003,990(1-2):303-309
Application of capillary isotachophoresis (CITP) for the analysis of water extracts of the dust samples collected in different periods in air-filtration devices in Prague car traffic tunnels and in Parisian metro station is presented. The extracts were analyzed in cationic mode with a leading electrolyte (LE) of 10 mM KOH, 25 mM acetic acid, pH 4.4, and a terminating electrolyte (TE) of 10 mM β-alanine, adjusted to pH 4.4 with acetic acid, and in anionic mode with LE 10 mM HCl, 20 mM histidine, pH 5.8 and TE 10 mM 2-(N-morpholino)ethanesulphonic acid, pH 3.7. Extracted amounts of UV-absorbing substances, including pollen allergens and organic pollutants, the number of the found components and concentrations of some inorganic ions (e.g. Cl−, K+, Na+, Ca2+) in the dust samples were determined. It was found that the extracted amounts of anionic components and their number were much higher than those of cationic components. Significant differences have been found in the analyses of the extracts of different origin. Much more material and more components were present in the extracts of samples from the pollen-rich period than from the pollen-free period, especially in anionic CITP mode. 相似文献
53.
54.
A novel angiogenesis inhibitor, 5-demethoxyfumagillol (1), was obtained by isolation, purification and saponification of cultured broth of Aspergillus fumigatus. The structure was assigned as (3R,4R,6R)-4-[(2R,3R)-2-methyl-3-(3-methyl-but-2-enyl)-oxiranyl]-1-oxa-spiro[2,5]octan-6-ol (1) by spectroscopic analysis and confirmed by independent synthesis from fumagillol (3). In addition, 6-O-(chloroacetylcarbamoyl)-5-demethoxyfumagillol (7) showed a potential anti-angiogenic activity in CAPE cells in vitro. 相似文献
55.
This paper deals with the bilinear symmetrization problem associated with Sobolev inner products. Let 007B;Q
n
}
n=0
be the sequence of monic polynomials orthogonal with respect to a Sobolev inner product of order 1 when one of the measures is discrete and the other one is a nondiscrete positive Borel measure. Furthermore, assume that the supports of such measures are symmetric with respect to the origin so that the corresponding odd moments vanish. We consider the orthogonality properties of the sequences of monic polynomials 007B;P
n
}
n=0
and {R
n
}
n=0
such that Q
2n
(x)=P
n
(x
2), Q
2n+1(x)=xR
n
(x
2). Moreover, recurrence relations for {P
n
}
n=0
and {R
n
}
n=0
are obtained as well as explicit algebraic relations between them. 相似文献
56.
57.
A. E. Chalykh V. K. Gerasimov A. V. Mironov S. A. Kuptsov N. R. Kil’deeva 《Polymer Science Series A》2012,54(4):282-289
Isothermal cross sections of amorphous separation diagrams of the ternary systems poly(ɛ-caprolactone)-co-poly(acryl methacrylate) Eudragite RS-methylene chloride and poly(ɛ-caprolactone)-co-poly(acryl methacrylate) Eudragite E-methylene chloride are obtained via the experimental methods of turbidity points and
analytical transmission electron microscopy and the calculation semi-empirical method of constructing boundary lines of phase
diagrams. It is shown that the composition of copoly(acryl methacrylate) affects the length of the solubility region in the
ternary phase diagram and the character of the anisotropy of films prepared via solvent evaporation. The determination of
coordinates of figurative points corresponding to the completion of phase separation shows that the mechanism of phase separation
for both systems is of the spinodal type. The specific orientation of polycaprolactone crystallites during film preparation
from the poly(ɛ-caprolactone)-Eudragite RS mixture is determined by the morphology of the film formed during solvent evaporation
and the phase composition. 相似文献
58.
Kil Sik Min Yoon Jae Kim Hyun Jin Ko Dae Hyun Kwak Tae Wook Kim Jong Won Shin Bong Gon Kim 《Journal of Physical Organic Chemistry》2014,27(12):960-966
We have isolated two isomeric solids 1 and 2 of N,N′‐bis(3,5‐dichlorosalicylidene)‐2,2′‐ethylenedianiline and characterized by IR, UV/Vis, X‐ray powder diffraction, thermogravimetric analysis/differential thermal analysis, and X‐ray crystallography. Although the solids are same formulas, each shows different colors and crystal structures. Orange solid ( 1 ) shows endo conformation while yellow solid ( 2 ) exhibits exo form depending on packing modes. UV/Vis spectra of 1 and 2 appear very similar patterns in the solid state; however, the bands of 1 are slightly red‐shifted compared with those of 2 . 1 displays a strong fluorescent emission band at ~582 nm while 2 shows an intense fluorescent signal at ~563 nm. The charge density populations of 1 and 2 have been studied by computational simulations using density functional theory at pbe1pbe/6‐311G** level. The calculated highest occupied molecular orbital and lowest unoccupied molecular orbital energies of 1 and 2 confirm that charge transfer occurs within the organic molecules. The energy difference of HOMO‐LUMO in 1 is smaller slightly than that of 2 about 0.05 eV (~17 nm). Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
59.
Determination of air-loop volume and radon partition coefficient for measuring radon in water sample
Kil Yong Lee William C. Burnett 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(2):1359-1365
A simple method for the direct determination of the air-loop volume in a RAD7 system as well as the radon partition coefficient was developed allowing for an accurate measurement of the radon activity in any type of water. The air-loop volume may be measured directly using an external radon source and an empty bottle with a precisely measured volume. The partition coefficient and activity of radon in the water sample may then be determined via the RAD7 using the determined air-loop volume. Activity ratios instead of absolute activities were used to measure the air-loop volume and the radon partition coefficient. In order to verify this approach, we measured the radon partition coefficient in deionized water in the temperature range of 10–30 °C and compared the values to those calculated from the well-known Weigel equation. The results were within 5 % variance throughout the temperature range. We also applied the approach for measurement of the radon partition coefficient in synthetic saline water (0–75 ppt salinity) as well as tap water. The radon activity of the tap water sample was determined by this method as well as the standard RAD-H2O and BigBottle RAD-H2O. The results have shown good agreement between this method and the standard methods. 相似文献
60.
Borbála Boros Silvia Jakabová Tamás Madarász Réka Molnár Bertalan Galambosi Ferenc Kilár Attila Felinger Ágnes Farkas 《Chromatographia》2014,77(17-18):1129-1135
Bergenia species (Saxifragaceae) are important sources of herbal medicines in Asia, mainly in Russia. Various plant parts are valued for their antibacterial, anti-inflammatory, antioxidant sand adaptogenic effect, and used for the dissolution of kidney and bladder stones. In this study a rapid reversed phase liquid chromatography (RP-HPLC) method has been developed for rapid screening and identifying of the main active components in leaf samples of Bergenia accessions. The main goal of this study was to develop an efficient method for the simultaneous identification and detection of arbutin, bergenin and gallic acid from Bergenia leaf samples, which were extracted with a methanolic solvent mixture [methanol:water = 1:1 (v/v)]. Chromatographic separations were performed on a reversed phase Luna C18(2)-HST HPLC column. This chromatographic system provided increased speed and efficiency for separations, without the need for ultra-high pressures. Reversed phase HPLC coupled with diode array detector method was used for the analysis. The method was validated using ICH guidelines. The level of gallic acid was significantly higher in Bergenia crassifolia samples compared to Bergenia cordifolia. However, the samples of the two Bergenia species did not differ substantially regarding the concentrations of arbutin and bergenin. The novel method proved to be fast and allowed sufficient separation and quantification of arbutin, bergenin and gallic acid, the most important bioactive compounds of Bergenia leaves; thus facilitating rapid screening and quality assessment of Bergenia samples of various botanical and geographical origins. 相似文献