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排序方式: 共有155条查询结果,搜索用时 15 毫秒
51.
Prof. Dr.-Ing. E. Andresen Dipl-Ing. U. Baertz 《Electrical Engineering (Archiv fur Elektrotechnik)》1977,59(1):23-37
Übersicht Bei asynchronen Linearmaschinen, wie dem Langstatormotor mit diskontinuierlicher Statoranordnung und steuerbarem Sekundärteil für Schnellbahnantriebe, dem Flüssigmetall-MHD-Wandler oder dem Sektormotor ist eine Herabsetzung der Sekundärleitfähigkeit außerhalb des Statorbereiches möglich. Der Einfluß einer solchen ortsabhängigen Leitfähigkeit des Sekundärteils auf die Feld- und Stromverteilung und auf die Betriebskennlinien wird untersucht.
Die Verfasser danken der Deutschen Forschungsgemeinschaft für die finanzielle Unterstützung des Forschungsvorhabens. 相似文献
Contents Linear induction machines, such as the high speed ground transportation motor with discontinuously arranged stators along the guideway and controllable secondary on the train, further the liquid metal MHD convertor or the sector motor allow to be operated with reduced conductivity of the secondary outside the stator. The influence of a stator position dependent conductivity of the secondary on field and current distribution and on the characteristics is analysed.
Die Verfasser danken der Deutschen Forschungsgemeinschaft für die finanzielle Unterstützung des Forschungsvorhabens. 相似文献
52.
O Andresen 《Canadian Metallurgical Quarterly》1976,48(1):51-59
The levels of 5alpha-androstenone and testosterone in peripheral plasma and 5alpha-androstenone in fat collected from 18 boars selected according to thickness of back fat and rate of gain were evaluated. Sampling was started when the animals were about 100 days of age and samples were collected every 14 days until the boars were about 240 days old. The steroid profiles varied considerably between boars, although an increase in steroid levels was found in most animals with the onset of adolescence. The regression line for the level of 5alpha-androstenone in fat and the age of the animals in days was found to be y = 0.02x-1-31. High coefficients of correlation were found between the concentration of 5alpha-androstenone in peripheral plasma and fat (r = 0-78) and between levels of 5alpha-androstenone and testosterone in peripheral plasma (r = 0-64). Levels of 5alpha-androstenone in peripheral plasma above about 15 ng/ml were usually accompanied by a heavy accumulation of 5alpha-androstenone in adipose tissue. The use of four of the boars for mating resulted in increased steroid levels in peripheral plasma and fat. Significantly higher levels of 5alpha-androstenone and testosterone were found in the peripheral plasma of boars selected for fatness and a low rate of gain than in boars selected for low back-fat thickness and a high rate of gain. 相似文献
53.
Adenovirus type 2 DNA, specifically labeled at the termini for DNA replication, was prepared by isolation of viral DNA molecules which were completed during short pulses with 3H-thymidine. The distribution of radioactivity in the two complementary strands at the termini for DNA replication was determined by liquid phase hybridization and gelelectrophoresis. At the right-hand terminus, nearly all radioactivity was found in the viral h strand, whereas at the left-hand terminus, most radioactivity was confined to the viral l strand. The results suggest that both molecular ends serve as origins and termini for replication of adenovirus type 2 DNA. 相似文献
54.
Dr.-Ing. Egon Christian Andresen 《Electrical Engineering (Archiv fur Elektrotechnik)》1966,50(5):319-331
Übersicht Die Stromwendungsgüte von Gleichstrom- und Wechselstrom-Kommutatormaschinen läßt sich mit Hilfe von Windungen im Wendepolluftspalt verbessern, in die Kondensatoren eingeschaltet sind. Die Verbreiterung der funkenfreien Zonen wird abhängig von der Kapazität und der Bürstenbreite an einer kompensierten Gleichstrommaschine gemessen und anhand eines vereinfachten Ersatzschaltbildes rechnerisch gedeutet. Die dämpfende Wirkung des massiven Ständerjoches und der Feldwicklung werden aus den Meßergebnissen rechnerisch näherungsweise bestimmt. Die prozentualen Zahlenwerte haben für einfache Abschätzungen allgemeinen Wert, da die Streufaktoren größerer Maschinen nur geringfügig voneinander abweichen.
Summary The commutation efficiency of d. c. and a. c. commutator machines can be improved by the presence of windings in the interpole airgap into which capacitors are switched. The increase in width of the spark-free zones, which is dependent on the capacitance value and the brush width, is measured on a compensated d. c. machine and calculated by means of a simplified equivalent circuit diagram. The damping effect of the solid stator yoke and the field winding is approximately calculated from the measured results. The percentage numerical values are of general value for simple estimations, since the leakage coefficients of larger machines vary only by insignificant amounts.相似文献
55.
Akad. Oberrat Dr.-Ing. Klaus Andresen Dr.-Ing. Dieter Ottl Prof. Dr.-Ing. Reinhold Ritter 《Forschung im Ingenieurwesen》1977,43(3):69-74
Zusammenfassung Die Hysterese und die Energiedissipation in einer auf Zug beanspruchten Schraubverbindung werden rechnerisch und experimentell
ermittelt. Das Rechenmodell besteht aus Zugst?ben mit konstanter, parabelf?rmiger oder polynomartig verteilter Querlast in
der Kontaktzone als Folge der Schraubenanpre?kraft. Wenn eine Zuglast wirkt, verschieben sich die St?be relativ zueinander.
Die abgeleiteten Verschiebungs-Last-Funktionen und die Verlustarbeiten h?ngen von der gew?hlten Querkraftverteilung ab. Rechnung
und Experiment werden mit Hilfe der Verlustarbeit in Abh?ngigkeit von der Zugkraft quantitativ verglichen. Die beste übereinstimmung
ergibt sich für parabelf?rmige und polynomartige Querlast. Auch die rechnerisch und experimentell ermittelten Formen der Hystereseschleifen
unterscheiden sich nur wenig voneinander. Mit dem Rechenmodell k?nnen zus?tzliche Zwischenzyklen bei Be- und Entlastungsvorg?ngen
erfa?t werden.
Akad. Oberrat 相似文献
56.
Direct chemical analysis of solids by laser ablation in an ion storage time-of-flight mass spectrometer 总被引:1,自引:0,他引:1
A laser ablation/ionization mass spectrometer system is described for the direct analysis of solids, particles, and fibers. The system uses a quadrupole ion trap operated in an ion storage mode, coupled with a reflectron time-of-flight mass spectrometer). The sample is inserted radially into the ring electrode, and an imaging system allows direct viewing and selected analysis of the sample. Measurements identified trace contaminants of Ag, Sn, and Sb in a Pb target with single laser shot experiments. Resolution (m/Delta m) of 1500 and detection limits of approximately 10 pg have been achieved with a single laser pulse. The system configuration and related operating principles for accurately measuring low concentrations of isotopes are described. 相似文献
57.
Elbphilharmonie Hamburg – Fundamental considerations to co‐operation between engineer and architect At present the authorization (?) planning for the Elbphilharmonie runs in Hamburg. The project becomes up to the commencement of construction, which is planned already for at the beginning of 2007, further concretized and refined. The architectural idea to touch down on old, 1964 built dock silo a Philharmonic Concert Hall with luxury dwellings and a hotel was developed in the context of an investor project. This idea was so convincingly that it found now a very broad basis in the population and is now in the planning process, with the goal, this unique and for Hamburg important project not only to plan but also to build. 相似文献
58.
Bovine kappa-casein represents a major portion of the total protein present in milk and is required for formation of the caseinate micelles responsible for the transportation of both calcium and phosphorous. Two monoclonal antibodies directed against bovine kappa-casein have been isolated. Both monoclonal antibodies are highly specific for bovine kappa-casein. Western analysis of denatured kappa-casein suggests epitope specificity is, in part, conformationally dependent. Additional epitope mapping with chymosin and neuraminidase also suggest antibody binding is in the region of the amino acid sequence Pro-Thr-Thr at positions 92 to 94 and 134 to 136. 相似文献
59.
Pyrolysis of an organic concentrate from municipal solid waste was carried out using a bench-scale fluidized bed reactor at 350-540 °C comparing Al2O3 with activated olivine sand as bed materials. A maximum oil yield of 50 wt.% was obtained using the activated olivine sand at 400 °C while only 45 wt.% was obtained at 500 °C using Al2O3. The bio-oils using activated olivine sand at 400 °C had an H/C ratio of 1.50 and O/C ratio of 0.37 and were less aromatic and less nitrogenous compare to the oils obtained using Al2O3 at 400 °C where the H/C ratio was 1.32 and the O/C ratio was 0.44. The aromatic compounds were found to be reduced while the aliphatic compounds increased in the oils generated using activated olivine sand. The calorific value of the bio-oil at 500 °C was 29 MJ/kg using activated olivine sand while the bio-oil using Al2O3 was 23 MJ/kg. The presence of iron, magnesium and other oxides probably promotes the removal of oxygen, which indicates that the activation energy of C―O bond breakage is reduced compared to the C―C bonds, thus promoting dehydration, decarboxylation and alkalation reactions to produce aliphatic fatty acid at lower temperatures. 相似文献
60.
Carl Andresen 《Electrical Engineering (Archiv fur Elektrotechnik)》1937,31(5):348-350
Ohne Zusammenfassung 相似文献