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961.
The low temperature spectra of TcO
4
–
and ReO
4
–
both show two band systems with pronounced vibrational structures. The bands are identified as1
A
11
T
2 transitions. No other bands are observed with certainty. It seems likely that the KClO4 crystals contain KReO4 crystallites. They are therefore not pure mixed crystals. It is concluded that the virtual orbital (2e) used in the construction of the low lying states resembles an atomic nd orbital more and more when going from n=3, Mn to n=5, Re.
Nachwuchsstipendiat, Schweizerischer Nationalfonds. 相似文献
Zusammenfassung Die Tieftemperaturspektren von TcO 4 – und ReO 4 – zeigen beide zwei Bandensysteme mit ausgeprägten Schwingungsstrukturen. Die Banden werden als 1 A 11 T 2-Übergänge identifiziert. Keine anderen Banden werden mit Sicherheit beobachtet. Es scheint wahrscheinlich, daß die KClO4-Kristalle KReO4-Kristallite enthalten und deswegen keine reinen Mischkristalle sind. Es wird geschlossen, daß das virtuelle Orbital (2e), welches zur Konstruktion der tiefliegenden Zustände gebraucht wird, in der Reihe n=3, Mn bis n=5, Re immer weitgehender einem nd-Atomorbital ähnelt.
Nachwuchsstipendiat, Schweizerischer Nationalfonds. 相似文献
962.
Zusammenfassung FeCl3 liegt in PhPOCl2 als roter solvatisierter Komplex, in Gegenwart von polaren Chloriden als gelbes [FeCl4]–-Ion vor. BCl3, SnCl4, TiCl4, PCl5 und wahrscheinlich auch HgCl2 und SbCl3 geben an FeCl3 je 1 Chloridion ab, ZnCl2 gibt beide Chloridionen und AlCl3 zwei Chloridionen fast vollständig und ein drittes in geringem Umfang ab. Die Donorstärke nimmt in der Reihe KClEt4NCl>1/2 AlCl3>-TiCl4>PCl5>1/2 ZnCl2>BCl3 SnCl4[AlCl]++>HgCl2>SbCl3 ab. Als Chloridionenakzeptor ist nur SbCl5 dem FeCl3 ebenbürtig, die oben genannten Chloride sind wesentlich schwächere Akzeptoren.Mit 4 AbbildungenHerrn Professor Dr.L. F. Audrieth zum 60. Geburtstag gewidmet. 相似文献
963.
Carolina A. Pinto P. M. Büchler J. Dweck 《Journal of Thermal Analysis and Calorimetry》2007,87(3):715-720
The catalyst
used in fluidized catalytic cracking (FCC) units of refineries after several
recovery cycles in regeneration units, reduces its activity and it is partially
substituted by new catalyst in the process. As it has a high silicon and aluminum
oxides content, the pozzolanic properties of a Brazilian FCC spent residual
catalyst, used in different substitution degrees to cement, were evaluated
by three thermal analysis techniques during the early stages of hydration
of a type II Portland cement. NCDTA curves show in real time that the residual
catalyst, accelerates the stages of cement hydration. TG and DSC curves of
respective pastes after 24 h of hydration evidence the pozzolanic activity
of the waste, respectively, by the lower water mass loss during the dehydroxylation
of the residual calcium hydroxide and by the lower dehydroxylation endothermal
effect. Within the analyzed period, the higher is the cement substitution
degree, the higher is the pozzolanic activity of the residual catalyst. 相似文献
964.
The first example of the formation of hydrogen-deficient radical cations of the type [M + H](.2+) is demonstrated to occur through a one-electron-transfer mechanism upon low-energy collision-induced dissociation (CID) of gas-phase triply charged [Cu(II)(terpy)(M + H)](.3+) complex ions (where M is an angiotensin III or enkephalin derivative; terpy = 2,2':6',2'-terpyridine). The collision-induced dissociation of doubly charged [M + H](.2+) radical cations generates similar product ions to those prepared through hot electron capture dissociation (HECD). Isomeric isoleucine and leucine residues were distinguished by observing the mass differences between [z(n) + H](.+) and w(n)(+) ions (having the same residue number, n) of the Xle residues. The product ion spectrum of [z(n) + H](.+) reveals that the w(n)(+) ions are formed possibly from consecutive fragmentations of [z(n) + H](.+) ions. Although only the first few [M + H](.2+) species have been observed using this approach, these hydrogen-deficient radical cations produce fragment ions that have more structure-informative patterns and are very different from those formed during the low-energy tandem mass spectrometry of protonated peptides. 相似文献
965.
Klaus van Benthem Stephan Krämer Wilfried Sigle Manfred Rühle 《Mikrochimica acta》2002,138(3-4):181-193
An understanding of the correlation between microstructures and properties of materials require the characterization of the
material on many different length scales. Often the properties depend primarily on the atomistics of defects, such as dislocations
and interfaces. The different techniques of transmission electron microscopy allow the characterization of the structure and
of the chemical composition of materials with high spatial resolution to the atomic level: high resolution transmission electron
microscopy allows the determination of the position of the columns of atoms (ions) with high accuracy. The accuracy which
can be achieved in these measurements depends not only on the instrumentation but also on the quality of the transmitted specimen
and on the scattering power of the atoms (ions) present in the analyzed column.
The chemical composition can be revealed from investigations by analytical microscopy which includes energy dispersive X-ray
spectroscopy, mainly quantitatively applied for heavy elements, and electron energy-loss spectroscopy. Furthermore, the energy-loss
near-edge structure of EELS data results in information on the local band structure of unoccupied states of the excited atoms
and, therefore, on bonding. A quantitative evaluation of convergent beam electron diffraction results in information on the
electron charge density distribution of the bulk (defect-free) material.
The different techniques are described and applied to different problems in materials science. It will be shown that nearly
atomic resolution can be achieved in high resolution electron microscopy and in analytical electron microscopy. Recent developments
in electron microscopy instrumentation will result in atomic resolution in the foreseeable future. 相似文献
966.
Cebulak S. Langier-Kuüniarowa A. Grotek I. 《Journal of Thermal Analysis and Calorimetry》2002,69(1):227-235
Oxyreactive thermal analysis (OTA) carried out in the conditions of full access of oxygen to each reacting particle of the sample investigated is a suitable method for the determination of important properties of the organic matter dispersed in the rocks. Its results may be easily evaluated to the form of values to be used in a clear diversification and classification system of organic matter/kerogen, as well as to the evaluation of its transformation process in a rockmass. The OTA also enables the distinguishing of the transformation stages and the investigation of the results of the gaseous products liberation from organic matter and kerogen. The OTA method may be applied as a complementary one for the Rock Eval analysis and be used for the organic geochemical and bituminological studies for geological bitumen prospecting.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
967.
B. Karakelle N. Öztürk A. Köse A. Varinlioğbrevelu A. Y. Erkol F. Yilmaz 《Journal of Radioanalytical and Nuclear Chemistry》2002,254(3):649-651
The city of Kocaeli is in the western part of Anatolia in Turkey and has a population of approximately 1.000.000. There is no information about radioactivity in the Kocaeli soils samples so far. For this reason, the concentrations of the natural radionuclides in soil samples from 27 different sampling stations in Kocaeli Basin and its surroundings have been determined. The results have been compared with other radioactivity measurements in different country"s soils. The typical concentrations of 137Cs, 238U, 40K, 226Ra, 232Th found in surface soil samples ranged from 2±0.6 to 25±6 Bq/kg, from 11±4 to 49±10 Bq/kg, from 161±30 to 964±127 Bq/kg, from 10±4 to 58±11 Bq/kg, and from 11±3 to 65±13 Bq/kg, respectively. 相似文献
968.
Deo SK 《Analytical and bioanalytical chemistry》2004,379(3):383-390
Reassembly of protein from its peptide fragments is a technique that can have many applications in the bioanalytical field. Typically, a reporter protein fragmented into its two peptides is employed as a label in this study. This fragments of peptide can reassemble yielding an active functional reporter. This reassembly of the protein can be assisted by non-covalently interacting peptides or proteins, which are attached to the fragmented reporter. This technique has been employed in several applications including study of protein–protein interactions, antibody screening, immunoassays, and high-throughput screening. This review focuses on different reporters employed in the study of reassembly of proteins and applications of this strategy in bioanalysis. 相似文献
969.
Duncan?P.?FaggEmail author Vladislav?V.?Kharton Jorge?R.?Frade 《Journal of Solid State Electrochemistry》2004,8(9):618-625
Small (2 mol%) cobalt oxide additions to ceria-gadolinia (CGO) materials considerably improve sinterability, making it possible to obtain ceramics with 95–99% density and sub-micrometre grain sizes at 1,170–1,370 K. The addition of Co causes a significant shift of the electrolytic domain to lower pO2. This modification to the minor electronic conductivity of the electrolyte material has influence on the cathodic oxygen reduction reaction. The impedance technique is shown to provide information not only about polarisation resistance, but also about the active electrode area from analysis of the current constriction resistance. It is demonstrated that this current constriction resistance can be related to the minor electronic contributions to total conductivity in these materials. A simple imbedded grid approach gives control of the contact area allowing the properties of the electrolyte materials to be studied. A much lower polarisation resistance for the Co-containing CGO electrolyte is observed, which can be clearly attributed to an increased three-phase reaction area in the Co-containing material, as a consequence of elevated p-type conductivity. 相似文献
970.
During recent years high-performance liquid chromatography has become an excellent tool for the determination of antibiotics in biological fluids. Compared with biological assays, the major benefits of this method are specificity and rapidity. In particular, the determination of biologically inactive metabolites emphasizes that this technique plays an outstanding role for the analysis of antibiotics. This paper describes how the method can be used in the analysis of several antibiotics and demonstrates the efficacy of this method for clinical microbiology. Methods for the determination in biological fluids of acylaminopenicillins (azlocillin, mezlocillin, piperacillin and aspoxicillin), quinolones (ciprofloxacine, norfloxacine and ofloxacine), a penem (imipenem) and a cephalosporin (cefixime) are summarized. Furthermore, their application to in vitro studies and their trial in clinical studies are described. 相似文献