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81.
H. Seliger E. Rössner G. Aumann V. Genrich M. Holupirek T. Knäble und M. Philipp 《Colloid and polymer science》1977,255(11):1143
Ohne Zusammenfassung 相似文献
82.
Summary Using column switching techniques a rapid and precise HPLC method for the determination of pentoxifylline was developed. Shorter
precolumns with RP 2 filling material and longer purging times at neutral pH reduce the amount of interfering peaks while
retaining a 100% extraction yield. Of all stationary phases of the analytical column tested only Nucleosil Phenyl yielded
base line separation and acceptable life time of the column.
Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984 相似文献
83.
84.
85.
T. Aumann K. Sümmerer H. Geissel B. Blank T. Brohm H. -G. Clerc S. Czajkowski C. Donzaud A. Grewe E. Hanelt A. Heinz H. Irnich M. de Jong A. Junghans J. V. Kratz A. Magel G. Münzenberg F. Nickel M. Pfützner A. Piechaczek C. Röhl C. Scheidenberger K. -H. Schmidt W. Schwab S. Steinhäuser W. Trinder B. Voss 《Zeitschrift für Physik A Hadrons and Nuclei》1995,352(2):163-169
As part of a comprehensive study of uranium fragmentation at relativistic energies at the GSI projectile fragment separator, FRS, inclusive neutron-removal cross sections have been measured for severalxn channels at projectile energies of 600 and 950A MeV using targets of Al, Cu and Pb. The variation of the experimental cross sections with target nuclear charge is used to disentangle nuclear and electromagnetic contributions. The electromagnetic cross sections agree surprisingly well with a simple harmonic oscillator calculation of giant dipole resonances based on measured photonuclear cross sections and do not require an extra enhancement of the two-phonon giant dipole excitation as concluded from similar measurements with197Au. 相似文献
86.
87.
D. C. Aumann F. Buheitel J. Hauschild E. Robens H. Wershofen 《Journal of Radioanalytical and Nuclear Chemistry》1987,109(2):261-273
A combination of neutron activation and gamma-ray coincidence counting technique is used to determine the concentration of both long-lived fission produced129I and natural127I in environmental samples. The neutron reactions used for the activation of the iodine isotopes are129I(n, )130I and127I(n, 2n)126I. Nuclear interferences in the activation analysis of129I and127I can be caused by production of130I or126I from other constituents of the materials to be irradiated, i.e. Te, Cs and U impurities and from the125I tracer used for chemical yield determination. Chemical interferences can be caused by129I and127I impurities in the reagents used in the pre-irradiation separation of iodine. The activated charcoals used as iodine absorbers were carefully cleaned. Different chemical forms of added125I tracer and129I and127I constituents of the samples can cause different behaviour of125I tracer and sample iodine isotopes during pre-irradiation separation of iodine. The magnitude of the nuclear and chemical interferences has been determined. Procedures have been developed to prevent or control possible interferences in low-level129I and127I activation analysis. For quality control a number of biological and environmental standard samples were analyzed for127I and129I concentrations. 相似文献
88.
Dieter C. Aumann 《Angewandte Chemie (International ed. in English)》1975,14(3):117-136
Nuclear fission, although a physical phenomenon, is also of interest to the chemist. It was discovered by chemists, and chemists have made a material contribution to our present knowledge in this field. A comprehensive theory of nuclear fission has not, as yet, been developed, despite the volume of experimental data that has amassed in the 35 years since its discovery. In the past few years discoveries have been made which cannot be explained with conventional theoretical models of nuclear fission. The most important discovery was that of shape isomerism, a novel type of nuclear isomerism. It would appear that an accurate calculation of fission barriers is a prerequsite for precise explanation of many experimental findings. Recent results in this connection and an outline of the present state of our knowledge of nuclear fission constitute the main theme of this paper. 相似文献
89.
B. Suryanarayana K. Ramanjaneyulu Vemuri Raghavendra N. Murali D. Parajuli S. Yonatan Mulushoa Praveen Choppara P. Anantha Rao Y. Ramakrishna K. Chandramouli 《印度化学会志》2022,99(8):100623
Sm3+ substituted Ni–Co ferrite materials have been developed with the chemical compositions Ni0.5Co0.5Fe2-xSmxO4 for x = 0.0, 0.02, 0.04, and 0.06 by solid-state method. A spinel with a single-phase cubic structure was found through XRD analysis. Crystallite size and lattice parameter fluctuation with Samarium content, decreasing with Sm3+ doping. When Sm3+ is doped, SEM shows a uniform distribution of grains with increasing agglomeration, and the grain size decreases with samarium concentration. Two peaks of absorption mode FTIR spectra show their spinel nature. The samples' negative temperature coefficient measured by the two probe method indicates their semiconducting nature. The DC electrical resistivity of the Ni–Co ferrite system was found to increase from 5.99 × 103 (-cm) to 9.89 × 109 (-cm) as an increase in Sm concentration. VSM measurement gives the saturation magnetization for the concentration up to x = 0.04 decreased and then increased for x = 0.06. All these properties show our samples' higher applicability in various electronic devices. 相似文献
90.
Rudolf Aumann 《Angewandte Chemie (International ed. in English)》1988,27(11):1456-1467
Ketenimine complexes are readily available in great variety by reaction of isocyanides with carbene complexes. They have proven to be useful building blocks in new synthetic approaches to carbocyclic and N-heterocyclic four-, five-, and six-membered rings. The reactions involve new metal-induced bond formation patterns of the ketenimine ligands, which can be influenced across a wide range by varying the following five parameters: the metal, the ligands, and the three substituents on the N?C?C unit. 相似文献