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181.
The reaction of the metallocene dichlorides Cp2MCl2 (Cp = η5-C5H5; M = Ti, Zr, Hf, Mo, W) and Cp2′TiCl2 (Cp′ = η5-C5H4CH3) with equimolar amounts of dilithium-benzene-o-diselenolate, 1,2-(LiSe)2C6H4, gives the chelate complexes Cp2M(Se2C6H4) (M = Ti (I), Zr (II), Hf (III), Mo (IV), W (V)) and Cp2′Ti(Se2C6H4) (VI). CpTiCl3 reacts with 1,2-(LiSe)2C6H4 to give CpTiCl(Se2C6H4) (VII). The ring inversion activation parameters for I–VI can be determined by means of temperature-dependent 1H NMR spectroscopy in solution. The fragmentation behaviour of I–VII in the mass spectrometer has been investigated by pursuing metastable transitions, using linked-scan techniques. 相似文献
182.
For lattices with two kinds of points (black and white), distributed according to a translation-invariant joint probability distribution, we study statistical properties of the sequence of consecutive colors encountered by a random walker moving through the lattice. The probability distribution for the single steps of the walk is considered to be independent of the colors of the points. Several exact results are presented which are valid in any number of dimensions and for arbitrary probability distributions for the coloring of the points and the steps of the walk. They are used to derive a few general properties of random walks on lattices containing traps.Presented at the Symposium on Random Walks, Gaithersburg, MD, June 1982. 相似文献
183.
Lattice defects in Al, Cu, Ag and Au were studied by the perturbed angular correlation technique (PAC) using the probe atom100Pd/100Rh. The comparison of data obtained on interstitial trapping in Cu and Au at different probe atoms (100pd,111In) allows defect characterisation less affected by the respective probe. The trapping efficiency of100Pd for vacancy like defects is quite different to that of111In atoms. 相似文献
184.
Th. I. Pirtea 《Fresenius' Journal of Analytical Chemistry》1961,184(4):252-255
Zusammenfassung Es werden neue gravimetrische Bestimmungsmethoden für Mangan und Cadmium beschrieben, die auf der Fällung mit o-Phenanthrolinhydrochlorid in Gegenwart von Ammonium-oder Kaliumrhodanid beruhen. Die Niederschläge werden nach dem Waschen und Trocknen als [Mn(C12H8N2)2](SCN)2 bzw. [Cd(C12H8N2)2](SCN)2 gewogen. Die Methoden sind einfach, erfordern nur eine Arbeitsdauer von 1–1 1/2 Std und können ohne irgendwelche Veränderungen auch in Gegenwart kleiner Mengen anderer Elemente (Na, K, Ca, Sr, Ba, Mg, Be, Sc, Al, Cr und NH4
+-Ionen) verwendet werden. Zusatz von ÄDTA als Maskierungsmittel ermöglicht auch die Mangan-oder Cadmiumbestimmung in Gegenwart von Eisen. 相似文献
185.
Th Kraus 《Monatshefte für Chemie / Chemical Monthly》1964,95(3):733-738
Zusammenfassung Die Dampfdruckerniedrigung, die kondesierendes Argon bei 4,2° K auf Wasserstoff ausübt, wurde unter der Annahme, da die Stammfunktion desRaoultschen Gesetzes unter den herrschenden Bedingungen gültig ist, berechnet und mit Mewerten vonHengevoss undTrendelenburg verglichen. Aus der guten Übereinstimmung der Ergebnisse kann mit gro Wahrscheinlichkeit auf die Richtigkeit dieser Voraussetzungen geschlossen werden. 相似文献
186.
Jrgen Mller Carl Th. Pedersen Helge Egsgaard Elfinn Larsen 《Journal of mass spectrometry : JMS》1980,15(9):456-458
Electron impact spectra of thermolysis products of organic salts heated in the ion source of a mass spectrometer may give rise to organic ions corresponding to the cation of the salt. Field ionization mass spectrometry has been used as a facile method for detemining whether such an ion is due to ionization of the corresponding radical present in the gas phase, or to an electron impact induced fragmentation of a reaction product of higher mass. By comparison of the electron impact and field ionization spectra of a series of N-methyl pyridinium, tropylium and 1,2-dithiolylium salts it has been found possible to identify the radicals formed thermolytically, when present. 相似文献
187.
M. I. Krivopustov J. Adam V. Bradnova R. Brandt V. S. Butsev P. I. Golubev V. G. Kalinnikov J. Karachuk B. A. Kulakov E.-J. Langrock G. Modolo M. Ochs R. Odoj A. N. Premyshev V. S. Pronskich Th. Schmidt V. I. Stegailov J. S. Wan V. M. Zupko-Sitnikov 《Journal of Radioanalytical and Nuclear Chemistry》1997,222(1-2):267-270
First experiments on the transmutation of long-lived129I and237Np using relativistic protons of 3.7 GeV are described. Relativistic protons generate in extended Pb-targets substancial neutron fluences. These neutrons get moderated in paraffin and are used for transmutation as follows:129I(n,)130I and237Np(n,)238Np. The isotopes130I (T
1/2-12.36 h) and238Np (T
1/2=2.117 d) were identified radiochemically. One can estimate the transmutation cross-section (n,) in the given neutron field as (129I(n,))=(10±2)b and (237Np(n,))=(140±30)b The experiments were carried out in November 1996 at the Synchrophasotron, LHE, Dubna, Russia. The investigation has been performed at the Laboratory of High Energies, JINR, Dubna. 相似文献
188.
Sodium β-alumina crystals were elaborated by melting of a mixture of Na2CO3 and Al2O3 or by PbO flux evaporation and were studied by transmission electron microscopy. They exhibit regular planar defects lying in the {11.0} prismatic planes. These defects are described as antiphase boundaries for the cationic sublattice with fault vectors (such faults do not affect the anionic sublattice). As a consequence it would be interesting to study precisely the structure of the sodium β cationic lattice in the vicinity of the melting point. 相似文献
189.
Magnetic beads as interfacial nanoprobes 总被引:1,自引:0,他引:1
Helseth LE Wen HZ Heinig P Fischer TM 《Langmuir : the ACS journal of surfaces and colloids》2004,20(16):6556-6559
We use paramagnetic beads to probe strongly localized magnetic fields from one-dimensional nanomagnets. Using a polarization microscope in reflection mode, we find that light reflected from beads exhibits intensity fluctuations which may help us understand Brownian motion near interfaces. We estimate the height fluctuations and femtonewton forces acting on the beads. 相似文献