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1.
Nešetřil and Sopena introduced the concept of oriented game chromatic number. They asked whether the oriented game chromatic
number of partial k-trees was bounded. Here we answer their question positively.
Received: January 12, 2001 Final version received: February 25, 2002 相似文献
2.
3.
We compare the efficiency of two Faddeev-type approaches for the nuclear three-body Coulomb problem. The first one is a modification
of Noble’s approach, the second one is due to Sasakawa and Sawada. In an integral-equation formulation both of these methods
rely on the same Green’s operators and driving terms. The differences lie in the treatment of the long-range Coulomb potentials.
Numerical examples show that the modified Faddeev-Noble approach provides for faster convergence. 相似文献
4.
5.
M. Bokor T. Marek K. Süvegh K. Tompa A. Vértes Zs. Nemes-vetéssy K. Burger 《Journal of Radioanalytical and Nuclear Chemistry》1996,211(1):247-253
The complexes [Zn(1-propyltetraole)6](BF4)2 (Zn-ptz) and [Fe(methyltetrazole)6](BF4)2 (Fe-mtz) were investigated by positron annihilation and solid-state NMR spectroscopy. For Zn-ptz signs of structural rearrangements were found between 70 and 145 K. For the spin-crossover complex Fe-mtz a transition affecting the high-spin stat Fe2+ ions at lattice site B occurs below 15 K. 相似文献
6.
Summary Two new analytical techniques are described. The so-called injection technique operates on evaluating a dynamic concentration signal as a result of following the concentration change in a certain part of a flow-through channel after injecting a sample or reagent at a small volume into the current of an appropriate solution flowing at a constant rate.The second technique, the programmed coulometric titration technique, also uses the flow-through channel principle; that means this novel technique allows the more precise titrimetric way of analysis in flowing solutions. In the case of both techniques potentiometric and voltammetric detectors were involved. Several examples proved the multifold advantages of these techniques for environmental analysis.
Neue elektroanalytische Verfahren für die Umweltanalyse
Zusammenfassung Zwei neue Methoden werden beschrieben. Die sog. Injektionstechnik wertet ein dynamisches Konzentrationssignal aus, das sich aus der Änderung in einem Durchflußkanal ergibt, wenn Probe oder Reagens in kleinen Volumina in einen konstant fließenden Flüssigstrom injiziert werden. Das zweite Verfahren, die programmierte coulometrische Titration, erlaubt die Anwendung der genaueren titrimetrischen Technik auf fließende Lösungen. Bei beiden Methoden werden potentiometrische und voltammetrische Detektoren verwendet. Mehrere Beispiele zeigen die vielfachen Vorteile dieser Verfahren bei der Anwendung auf die Analyse von Umweltmaterial.
Presented at the 6th Annual Symposium on Recent Advances in the Analytical Chemistry of Pollutants, April 21–23, 1976; Vienna, Austria 相似文献
7.
Assignment of Saharan dust sources to episodes in Hungarian atmosphere by PIXE and TOMS observations
E. Koltay I. Borbély-Kiss Zs. Kertész Á. Z. Kiss Gy. Szabó 《Journal of Radioanalytical and Nuclear Chemistry》2006,267(2):449-459
Summary Thirty-seven episodes of dust intrusion were observed between February 12, 1991 and August 31, 2000 in the Hungarian atmosphere
and found to be of Saharan origin. They have been assigned to typical source areas in Northern Africa selected by systematic
investigations related to the Mediterranean Basin. Elemental concentrations and regional signatures deduced from PIXE analysis,
total suspended particle mass, and black carbon mass have been measured on dust samples collected in Debrecen, Hungary. These
data combined with Aerosol Index data, and dust plume axes obtained from TOMS data from NASA satellites were used for assigning
the most probable source areas of the dust transported to the sampling site. Our data and conclusions are in accordance with
other published investigations on the predominant role of Saharan dust emission in building up the aerosol load of the global
atmosphere. 相似文献
8.
Bogár F Szekeres Z Bartha F Penke B Ladik J 《Physical chemistry chemical physics : PCCP》2005,7(15):2965-2969
Two different helical conformations (alpha and 3-10 helices) of polyserine are studied using density functional theory. The infinite system characterized by exact translational-rotational symmetry is examined in vacuum using the BLYP exchange-correlation functional. Geometry analysis in terms of hydrogen bond strength and total energies of the different conformers are presented. The structural changes due to the presence of the serine side chain are identified comparing the polyserine and polyglycine chains. The rotational energy curves of the side chain are presented for both investigated helices. Band structures of polyserine and polyglycine conformers are also compared. 相似文献
9.
Fernandes L. P. Éhen Zs. Moura T. F. Novák Cs. Sztatisz J. 《Journal of Thermal Analysis and Calorimetry》2004,78(2):557-573
Thermoanalytical techniques, being rapid and un-expensive have been used for the investigation of the cyclodextrin inclusion
complexes for three decades. The conventional thermoanalytical techniques (TG and DTA/DSC) follow the thermal properties of
the uncomplexed compounds. Consequently, the inclusion complex formation as well as the liberation of the entrapped guest
cannot be followed. Monitoring the products of the thermal fragmentation of parent cyclodextrin and the included molecule(s),
applying TG-MS combined technique provides evidence concerning the inclusion complex formation, and besides, gives selective
signal to follow the decomposition of the cyclodextrin inclusion complexes. b-cyclodextrin inclusion complexes of Thymol and
Lippia sidoides Cham essential oil extract have been prepared and investigated using conventional and combined (TG-MS) thermoanalytical techniques.
The evolved gas analysis proved the inclusion complex formation between the host and guests. By the evaluation of the experimental
results the elaboration of the entrapped guests from the cyclodextrin cavity could be followed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
A chelate-forming ion exchanger, iminodiacetic acid/ethylcellulose, is used for the separation of trace metals from waters and different organic solvents. Added uranium was collected from sea waters with recoveries of about 97%. Graphite-furnace atomic absorption spectrometry and solution spectrophotometry were used to quantify the metals. For the direct determination of trace metals in waters by the graphite-furnace method, a simple matrix-matching method is described. The detection limit for cadmium was 0.1 μg l?1 and for lead 1 μg?1 in drinking water. 相似文献