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11.
M.?Gabriel M.?St?hr R.?M?llerRID=""ID=""Corresponding author. 《Applied Physics A: Materials Science & Processing》2002,74(2):303-305
. The structure of thin 3,4,9,10-perylenetetracarb-oxylic-dianhydride (PTCDA) films on Cu(110) was studied by scanning tunnelling microscopy (STM) from submonolayer to monolayer coverage. While no long-range ordering was found after deposition at room temperature, the formation of a well-defined superstructure is observed after thermal annealing. It appears that the formation of the superstructure is driven by the interaction between the oxygen atoms of the PTCDA and the copper atoms of the substrate. While the distance between the molecules fits well to the atomic lattice of the Cu(110) surface along the [1[`([¯])]1[¯]\bar\Box1\Box]]0] direction, the mismatch along the [001] direction leads to a periodic buckling normal to the surface accompanied by a restructuring of the substrate. 相似文献
12.
This work is probably the first attempt to identify the organic colouring materials contained in post-Byzantine textiles,
from the Holy Mountain of Athos. Samples extracted from seven ecclesiastical garments (15th–19th century) are investigated
by high performance liquid chromatography with UV-Vis diode array detection. The detection limits for alizarin, purpurin,
carminic acid, laccaic acid A, luteolin, apigenin, genistein, fisetin, sulfuretin, ellagic acid, indigotin and indirubin are
found to be within 0.002–0.029 μg mL−1. The following organic dyes are identified in the extracts: dyer’s broom (Genista tinctoria L.), young fustic (Cotinus coggygria Scop.), an indigoid dye source either indigo (Indigofera species) or woad (Isatis tinctoria L.), madder, cochineal and lac dye (Kerria lacca Kerr). Furthermore, the identification of a brazilein derivative indicates the presence of a Caesalpinia dye source in the samples.
Correspondence: Ioannis Karapanagiotis, Ormylia Art Diagnosis Center, Sacred Convent of the Annunciation, Ormylia, GR-63071
Chalkidiki, Greece 相似文献
13.
Tomohiro?KurataEmail authorView authors OrcID profile Shigeto?Oda Hiroshi?Kawahira Hideaki?Haneishi 《Optical Review》2016,23(6):955-967
We have previously proposed an estimation method of intravascular oxygen saturation \(({\rm SO}_2)\) from the images obtained by sidestream dark-field (SDF) imaging (we call it SDF oximetry) and we investigated its fundamental characteristics by Monte Carlo simulation. In this paper, we propose a correction method for scattering by the tissue and performed experiments with turbid phantoms as well as Monte Carlo simulation experiments to investigate the influence of the tissue scattering in the SDF imaging. In the estimation method, we used modified extinction coefficients of hemoglobin called average extinction coefficients (AECs) to correct the influence from the bandwidth of the illumination sources, the imaging camera characteristics, and the tissue scattering. We estimate the scattering coefficient of the tissue from the maximum slope of pixel value profile along a line perpendicular to the blood vessel running direction in an SDF image and correct AECs using the scattering coefficient. To evaluate the proposed method, we developed a trial SDF probe to obtain three-band images by switching multicolor light-emitting diodes and obtained the image of turbid phantoms comprised of agar powder, fat emulsion, and bovine blood-filled glass tubes. As a result, we found that the increase of scattering by the phantom body brought about the decrease of the AECs. The experimental results showed that the use of suitable values for AECs led to more accurate \({\rm SO}_2\) estimation. We also confirmed the validity of the proposed correction method to improve the accuracy of the \({\rm SO}_2\) estimation. 相似文献
14.
Tsubasa?OkamotoEmail authorView authors OrcID profile Hideyuki?Takahashi Eiji?Ohmichi Hitoshi?Ohta 《Applied magnetic resonance》2017,48(5):435-444
We report a novel force-detected high-frequency electron spin resonance (HFESR) technique using a microcantilever in the terahertz region. In this technique, we attach a tiny sample on the microcantilever end and the ESR signal is detected as the cantilever bending. The bending is sensitively detected by fiber-optic Fabry–Perot interferometry. We applied this technique to a tiny amount (~16 ng) of metalloporphyrin, a model substance of hemoproteins, and successfully observed ESR signals at multiple frequencies up to 0.5 THz. This result indicates that the sample volume needed in multi-frequency HFESR can be greatly reduced by several orders of magnitude, and our novel technique would be a promising tool for HFESR studies of metalloproteins in the future. 相似文献
15.
Vladimir V. TretyakovRID=""ID="" To whom correspondence should be addressed Sergey A. Rukolaine Alexandr S. Usikov Serge V. Makarov 《Mikrochimica acta》2000,132(2-4):361-364
Procedures for the preparation of bevels and the determination of their geometrical parameters have been developed. Using
these procedures study of compositional and optical spatially resolved inhomogeneities of AlxGa1−xN layers grown on (0001) sapphire have been studied by EPMA and cathodolu-minescence. It has been found that the nonuniform
distribution in depth of Al in epitaxial layers grown under constant conditions is connected with presence of stresses in
the layer. 相似文献
16.
Lemonia Valianou Ioannis Karapanagiotis Yannis Chryssoulakis 《Analytical and bioanalytical chemistry》2009,395(7):2175-2189
Different methods for the extraction of Dactylopius coccus Costa, Rubia tinctorum L., Isatis tinctoria L., Reseda luteola L., Curcuma longa L. and Cotinus coggygria Scop. from wool fibres are investigated using high-performance liquid chromatography with diode array detector (HPLC-DAD).
The efficiencies of five extraction methods which include the use of HCl (widely used extraction method), citric acid, oxalic
acid, TFA and a combination of HCOOH and EDTA are compared on the basis of the (a) number, (b) relative quantities, measured
as HPLC peak areas and (c) signal-to-noise ratios (S/N) of the compounds extracted from the wool substrates. Flavonoid glycosides and curcuminoids contained in R. luteola L. and C. longa L., respectively, according to liquid chromatography with mass spectrometry (LC-MS) identifications, are not detected after
treating the fibres with HCl. All the other milder methods are successful in extracting these compounds. Experiments are performed
using HPLC-DAD to compare the HPLC peak areas and the S/N of the following extracted compounds: indigotin, indirubin, curcumin, demethoxycurcumin, bisdemethoxycurcumin, fisetin, sulfuretin,
luteolin, luteolin-7-O-glucoside, apigenin, carminic acid, alizarin, puruprin and rubiadin. It is shown that the TFA method provides overall the
best results as it gives elevated extraction yields except for fisetin, luteolin, apigenin and luteolin-7-O-glucoside and highest S/N except for fisetin and luteolin-7-O-glucoside. It is noteworthy that treatment of the fibres with the typical HCl extraction method results overall in very low
S/N. The TFA method is selected for further studies, as follows. First, it is applied on silk dyed samples and compared with
the HCl method. The same relative differences of the TFA and HCl methods observed for the wool dyed samples are reported for
the silk dyed samples too, except for rubiadin, luteolin and apigenin. Thus, in most cases, the nature of the substrate (wool
or silk) appears to have negligible effects on the relative difference of the two extraction methods. Second, the selected
TFA method is applied to treat wool and silk historical samples extracted from textiles of the Mamluk period, resulting in
the identification of several colouring compounds. In all extraction methods mentioned above, DMSO is used to dissolve the
dyes, after acid treatment. 相似文献
17.
Christian GroßRID=""ID=""Supported by a DFG grant. 《manuscripta mathematica》2000,103(3):339-350
Let denote the eigenspace decomposition of a twisted affine Kac–Moody algebra with respect to an involution , where is a twisted loop algebra, is the center and d is the scaling element of . We endow with the standard bilinear symmetrical form.Then with and carries a Lorentzian signature. Let denote the group that corresponds to , then the adjoint representation of on can be restricted to and this submanifold is isometrical to the Hilbert space E
ε, where is the decomposition of the twisted loop algebra with respect to the induced involutionρ0.We thus obtain an affine representation on E
ε and we show that this representation is polar, i. e., there exists a submanifold that intersects all orbits, and intersects
them orthogonally.
Received: 16 February 2000
RID="
ID="Supported by a DFG grant. 相似文献
18.
Fran?ois DelaunayRID=""ID="" To whom correspondence should be addressed Claire Berthier Michel Lenglet Jean-Michel Lameille 《Mikrochimica acta》2000,132(2-4):337-343
The oxidation in air under isothermal conditions of Inconel 718 has been investigated at 900 °C. We have studied the firsts
stages of the high temperature oxidation mechanism. The oxidised samples were examined using a number of surface analytical
techniques including XPS and SEM-EDS. The results have shown that minor alloying elements strongly influence the oxidation
behaviour of the alloy:
Previous studies had shown that the rate of the external oxide scale growth and the intergranular oxide penetration during
oxidation of Inconel 718 at 900 °C in air are lower than those of Inconel X or Incoloy 800. We suggest that the formation
of a quasi continuous scale of the intermetallic phase Ni3Nb at the oxide-alloy interface could have an important contribution to the good oxidation resistance of Inconel 718. 相似文献
19.
Vladimir V. TretyakovRID=""ID="" To whom correspondence should be addressed Sergey V. Kazakov Alexander V. Bobyl Samuil G. Konnikov 《Mikrochimica acta》2000,132(2-4):365-375
An analytical model of an effective atomic number, Z
eff, for simultaneous calculation of composition and thickness of films on substrates that allows for backscattering processes
is presented. Comparison of dependencies of ϕ(ρz) parameters for film elements on electron beam energy, on atomic numbers of a film and a substrate and on film thickness
was done. The errors inherent in EPMA have been determined by comparing experimental data obtained on YBa2Cu3O7−x bulk crystals with model calculations. Possibility of EPMA as an effective technique for investigation of spatially inhomogeneous
objects was demonstrated by studying the correlation between composition and local superconducting properties (values of critical
temperature and critical current) of these films. 相似文献
20.
Independent Directed Triangles in a Directed Graph 总被引:2,自引:0,他引:2
Hong WangRID=""ID="" This research was supported by UIRC SEED GRANTS–KDY 《Graphs and Combinatorics》2000,16(4):453-462
If D is a directed graph of order n≥3 with , then D contains independent directed triangles. Moreover, the condition on the minimum degree is sharp in general.
Revised: April 19, 1999 相似文献