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391.
392.
Dariusz Cichoń 《Integral Equations and Operator Theory》1999,34(4):414-438
We give a generalization of the Newman-Shapiro Isometry Theorem to the case of Hilbert space-valued entire functions, which are square-summable with respect to the Gaussian measure on
n
, together with some applications in the theory of Toeplitz operators with operator-valued symbols. The study of various properties (such as density of domains, cores, closedness and boundedness from below) of these operators in illustrated with many relevant examples.Research supported by KBN under grant no. 2 P03A 041 10. 相似文献
393.
The uncertainty of carboxyhaemoglobin (COHb) determination in post-mortem blood samples by headspace gas chromatography with the use of methanizer and flame ionization detector was estimated. Four main components of uncertainty were identified, i.e. calibration, measurement repeatability, standard solutions preparation and sample preparation, and their contributions to the combined uncertainty were determined. The calibration step was the dominating source of uncertainty, counting for more than 39 % of overall variance. The contribution of remaining sources to the combined uncertainty was lower than 31 % (measurement repeatability), 21 % (standards preparation) and 12 % (sample preparation). The calculated absolute expanded uncertainty in samples containing 3.8–82 % mass fraction of COHb ranged between 2.2 % and 2.6 % (coverage factor 2), depending only slightly on the analyte level in the analysed sample. 相似文献
394.
Zbigniew Machnik Dariusz Bochenek Beata Wodecka-Dus Małgorzata Adamczyk Katarzyna Osińska 《The European Physical Journal B - Condensed Matter and Complex Systems》2016,89(2):34
The aim of the present work is to report investigations concerning the influence of homovalent modificators on relaxor properties of PBZT 25/70/30 ceramics. The selection of the proper homovalent additive was very important. Literature reports as well as data taken from the periodic table indicated, that calcium ions substitute themselves for lead ions with high likelihood of occurrence. The investigations showed that the substitution significantly changed the microstructure of ceramics – with grains of calcium modified ceramics decreasing and density increasing. The XRD measurements indicate that the pure PBZT ceramics as well as calcium dopant were characterised by tetragonal structure with space group I4 /mmm. Addition of calcium leads to a slight decrease in the lattice constant and crystal structure. The calcium modification also changes the dielectric properties. The temperature characteristic of the dielectric constant achieved a broadened maximum at temperature Tm, which decreases with increasing Ca content. The properties typical for ferroelectric relaxors weaken with increasing calcium dopant. 相似文献
395.
Vasyl' I. Zaremba Ute Ch. Rodewald Yaroslav M. Kalychak Yaroslav V. Galadzhun Dariusz Kaczorowski Rolf‐Dieter Hoffmann Rainer Pttgen 《无机化学与普通化学杂志》2003,629(3):434-442
The ternary indium compounds RE4Pd10In21 (RE = La, Ce, Pr, Nd, Sm) were synthesized from the elements in glassy carbon crucibles in a high‐frequency furnace. Single crystals of Sm4Pd10In21 were obtained from an indium flux. An arc‐melted precursor alloy of the starting composition ~SmPd3In6 was annealed with a slight excess of indium at 1200 K followed by slow cooling (5 K/h) to 870 K. All compounds were investigated by X‐ray powder diffraction and the structures were refined from single crystal diffractometer data. The RE4Pd10In21 indides are isotypic with Ho4Ni10Ga21, space group C2/m: a = 2314.3(2), b = 454.70(7), c = 1940.7(2) pm, β = 133.43(2)°, wR2 = 0.0681, 1678 F2 values for La4Pd10In21, a = 2308.2(1), b = 452.52(4), c = 1944.80(9) pm, β = 133.40(1)°, wR2 = 0.0659, 1684 F2 values for Ce4Pd10In21, a = 2303.8(2), b = 450.78(4), c = 1940.6(1) pm, β = 133.39(1)°, wR2 = 0.0513, 1648 F2 values for Pr4Pd10In21, a = 2300.2(2), b = 449.75(6), c = 1937.8(2) pm, β = 133.32(1)°, wR2 = 0.1086, 1506 F2 values for Nd4Pd10In21, and a = 2295.6(2), b = 447.07(4), c = 1935.7(1) pm, β = 133.16(1)°, wR2 = 0.2291, 2350 F2 values for Sm4Pd10In21, with 108 variables per refinement. All palladium atoms have a trigonal prismatic coordination. The strongest bonding interactions occur for the Pd—In and In—In contacts. The structures are composed of covalently bonded three‐dimensional [Pd10In21] networks in which the rare earth metal atoms fill distorted pentagonal channels. The crystal chemistry and chemical bonding in these indides is briefly discussed. Magnetic susceptibility measurements show diamagnetism for La4Pd10In21 and Curie‐Weiss paramagnetism for Ce4Pd10In21, Pr4Pd10In21, and Nd4Pd10In21. The neodymium compound orders antiferromagnetically at TN = 4.5(2) K and undergoes a metamagnetic transition at a critical field of 1.5(2) T. All the RE4Pd10In21 indides studied are metallic conductors. 相似文献
396.
Rafał Sitko Beata Zawisza Jerzy Jurczyk Dariusz Bochenek Małgorzata Płoñska 《Mikrochimica acta》2004,144(1-3):9-15
A method of wavelength-dispersive XRF analysis of Pb(Zr,Ti)O3 type ferroelectric ceramics doped with Pb(Nb,Mn)O3 and Bi2O3 is presented. The major elements Pb, Zr, Ti and minor elements Nb, Mn, Bi were determined. Matrix effects were minimized by using the thin layer method. Standards of the same chemical composition but varied masses were prepared to simplify calibration. To minimize errors resulting from inhomogeneity of a mass per unit area, the internal standard was used. Preparation of the sample consisted in digesting 25mg of the materials (with nickel as the internal standard) in sulfuric acid, evaporating to dryness and digesting in nitric acid and hydrogen peroxide, filling up to 25mL, and dropping 0.5mL of the solution onto a substrate. Standard samples were prepared by dropping different amounts of the multielement solution onto the substrate. The residual standard deviation for the reference sample of mass from 0.25mg to 0.7mg was within the range of 0.001–0.009mg (correlation coefficient 0.998–0.999) for major elements and within the range of 0.00003–0.0009mg (correlation coefficient 0.989–0.993) for minor elements. The detection limits for 0.5mg samples were within the range of 0.015%–0.35% for manganese and zirconium, respectively. 相似文献
397.
Marek?L.?G?ówkaEmail author Dariusz?Martynowski Andrzej?Olczak Czes?awa?Orlewska Henryk?Foks Joanna?Bojarska Ma?gorzata?Szczesio Jolanta?Go?ka 《Journal of chemical crystallography》2005,35(6):477-480
The title compound exists in a dipolar form both in the solvent-free and in the dihydrate crystal. Unit cell dimensions: 23.303(5), 7.3100(10), 15.030(3) Å, β = 101.78(3)∘; space group C2/c (monoclinic) with Z = 8. The molecule is flat due to extended conjugation in the central N=C(pyr)–N(3)H–N=C–S– fragment and three assisted intramolecular hydrogen bonds, one of them between the pyridine N atom (acceptor) and the N(3)H amine group as a hydrogen bond donor. As a result the molecule adopts an antiperiplanar conformation along the N–N bond and synperiplanar conformation along the neighbouring N–C bonds. Presence of two water molecules results in a very extensive network of intermolecular hydrogen bonds (eight) as compared with the crystal structure of the anhydrous compound. 相似文献
398.
Summary. Several enantiomerically pure 3,5-disubstituted isothiazol-5-ylideneamine hydrobromides were prepared by oxidation of chiral
3-amino-2,3-unsaturated thioamides. The starting thioamides derived from natural L-α-amino acids represent a novel group of synthetically useful chiral reactants. 相似文献
399.
Enthalpies of solution of NaCl and KCl in water- N, N-dimethylacetamide (DMA) mixtures (containing 0–20 mol.% of DMA) were measured at 25 ° C. The standard dissolution enthalpies for both investigated salts increase with increase in DMA content in the mixed solvent, in contrast with the dissolution enthalpies for other inorganic salts in the same mixtures examined so far. The calculated single-ion transfer enthalpies from water to water-DMA mixtures exhibit the opposite course with a distinct minimum for anions and a maximum for cations. The extrema of the ionic transfer enthalpies observed in all water-organic mixtures investigated thus far seem to be a consequence of the shape of the solvation enthalpy curves for Ph4P+ and BPh4− ions which are the basis for the calculation of individual ionic contributions and which are hydrophobically hydrated in water-organic solvents. 相似文献
400.
Dariusz Leszczynski Susanna Fagerholm Kirsti Leszczynski 《Photochemistry and photobiology》1996,64(6):936-942
Abstract— We examined the effects of broadband UVA radiation (320–400 nm) on a rat myeloid leukemia cell line–chlo-roma (ChL). A Phillips face tanner model HB 171/A was used as a light source. Chloroma were irradiated through a 5 mm thick glass Alter that cut off all of the UVB contamination. The irradiances were measured, from 250 to 400 nm, with a well-characterized and calibrated double-grating spectroradiometer Optronic 742. The overall uncertainty of dose evaluation was estimated to be <15% (2s?). The cells were irradiated with UVA doses of 4 and 8 J/cm2 and cultured thereafter for 24 h. After this period of time, a marked decline up to 50% was observed in cell proliferation in UVA-irradiated ChL cultures. The cell proliferation decline was found to be caused by simultaneously occurring G2/M phase cell cycle arrest and apoptosis in part of the UVA-irradiated ChL population. Concomitantly, with the decline in cell proliferation, an increase was observed in the expression of the major histocompatibility (MHC) class I and II antigens. Because protein kinase C (PKC) is known to regulate cell proliferation, apoptosis and expression of MHC antigens, and because UVA was shown to regulate PKC activity/expression, we therefore examined whether UVA irradiation has any effect on the expression of isozymes of PKC. Western blots revealed that ChL express α, βI, δ, α, γ, and π isozymes of PKC and that expression of all isozymes declined 24 h after UVA irradiation (8 J/cm2). Finally, PKC activation in ChL by exposure to phorbol ester caused cell cycle arrest in G1 phase but did not induce apoptosis. This suggests that the previously shown UVA-induced PKC activation in ChL might be responsible for the induction of MHC antigens but the simultaneously observed ChL apoptosis is likely to be mediated by PKC down-regulation. All together, our results suggest that UVA, at irradiance levels that resemble the outdoor exposure, may have profound effects on the immune-related properties of leukocytes. Thus, we speculate that in vivo the immune functions of leukocytes passing through dermal capillaries might be altered by exposure to solar UVA radiation. 相似文献