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21.
Emission and absorption polarization spectra as well as emission lifetimes between room temperature and 5 °K have been measured of [Cr urea6]X3 single crystals, where X stands for ClO
4
–
, J–, NO
3
–
, Br–, Cl–, F–, and X3 for JSO
4
3–
. The strong temperature dependence of the fluorescence/phosphorescence-ratios, and of the emission lifetimes is discussed. The differences between the spectra as well as the emission lifetimes of the various salts can be attributed to an anion dependent trigonal perturbation.
Die Autoren danken dem Verband der Chemischen Industrie für finanzielle Unterstützung dieser Arbeit. 相似文献
22.
Veronicoside, a new iridoid glucoside from Veronica officinalis L. (Scrophulariaceae) A new iridoid glucoside, Veronicoside ( 1 ) has been isolated from Veronica officinalis L. The structure of 1 has been determined by chromatographic and spectroscopic analysis as 6-benzoylcatalpol. 相似文献
23.
Axial blocking in various binary (GaAs, GaP, InSb, GaN) and ternary ((Ga, Al)P; (Ga, Al)As; (Ga, Al)Sb; (Ga, In)As) single crystals and epitaxial layers of the AIIIBV-type has been investigated by means of Rutherford backscattering with 0.5 MeV- and 1 MeV-protons. The angular distributions of the latter has been measured with solid-state detectors and with photographic plates. The observed “zero-depth” values of the blocking dips are in fair agreement with theoretical predictions by Barrett. Some applications of proton blocking and channeling to AIIIBV-compounds by backscattering are briefly described and some measuring examples are given. 相似文献
24.
Roberta Cavalli Emilio Marengo Otto Caputo Elena Ugazio Maria Rosa Gasco 《Journal of Dispersion Science and Technology》2013,34(7):717-734
The influence of twenty five different alcohols on the formation of warm oil-in-water (O/W) microemulsions was investigated. Selected concentrations of each alcohol were added to fixed amounts of stearic acid, Tween 20 and water at 65 ° C. Fifteen alcohols formed microemulsions, at least at one of the concentrations. A pattern recognition study was performed to elucidate the activities of the alcohols by Principal Component Analysis (PCA). Linear Discriminant Analysis (LDA) was used to classify them. Two classification functions, obtained for alcohols forming / not forming microemulsions, suggest that the formation of warm O/W microemulsion is linked to the nature and the dimension/lipophilicity of the alcohol. 相似文献
25.
26.
A water-soluble fluorescent probe, rhodamine B hydrazide (RBH), was prepared and its properties for recognition of diacetyl
were studied. The method employs the reaction of diacetyl with RBH, a colorless and non-fluorescent rhodamine B spiro form
derivative to give a pink-colored fluorescent substance. In weakly acidic media, RBH reacts more selectively with diacetyl
than with other carbonyls, causing a large increase in fluorescence intensity and thereby providing an easy assay for the
determination of diacetyl. 相似文献
27.
Residence time spectra and material distributions in an operating caprolactam production plant were measured by means of sodium 24, bromine 82 and technetium 99m. The results of the tracerexperiments contributed to an optimization of the plant. 相似文献
28.
This is the second of two papers in which we study real and virtual photon-proton scattering in a nonperturbative framework. In the first paper we have identified the leading contributions to this process at high energies and have derived expressions for them which take into account the renormalisation of the photon-quark-antiquark vertex. In the present paper we investigate the approximations and assumptions that are necessary to obtain the dipole model of high energy scattering from the results derived in the first paper. We discuss the gauge invariance of different contributions to the scattering amplitude and point out some subtleties related to gauge invariance in the correct definition of a perturbative photon wave function. As a phenomenological consequence of the dipole picture we derive a bound on the ratio of the cross sections for longitudinally and transversely polarised photons. This bound is independent of any particular model for the dipole-proton cross section and allows one to test the validity of the assumptions leading to the dipole picture in particular at low photon virtualities. We conclude that the naive dipole model formula should be supplemented by two additional terms which can potentially become large at small photon virtualities. 相似文献
29.
Otto Schwelb 《Applied Physics A: Materials Science & Processing》1976,9(2):165-170
Relationships between complex power flow pseudo energy, propagation constant and complex frequency are presented for acoustic
waves in piezoelectric media. These relationships are essentially energy-power equations which apply to anisotropic, nonconservative,
dispersive, linear systems, analogous to those obtained by Chorney and Penfield for guided electromagnetic waves. At vanishing
piezoelectric coupling the powermode theorems split into a proper electromagnetic set and a proper mechanical set. By differentiating
the power-mode equations with respect to the complex frequency further results are obtained linking the group velocity with
power flow and energy storage. Conclusions may be drawn from these expressions regarding the signature of the dispersion (forward
or backward waves). The equipartition of pseudo energy is established at cut-off, and the vanishing of the complex power flow
at resonance. Examples including wave propagation in lossless and lossy media are included. 相似文献
30.
Otto Röschel 《Journal of Geometry》1992,44(1-2):160-170
We study a map of osculating elements of an affine Cayley- Klein (CK-) plane into the Lie algebraA
4(2) of the aequiform transformationsA
4(2) of the given plane. If we use the real projective spaceP
3() overA
4(2) each osculating element defines a straight line inP
3(). In the first part of this paper this map is studied in detail. In the second part we study second order properties of one- parameter motions and their corresponding properties in the Lie algebraA
4(2). This is done by considering the analogen to the formula of EULERSAVARY in the image spaceP
3() overA
4(2). 相似文献