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1.
Gerhard Buchbauer Johanna Gabmeier Ernst Haslinger Wolfgang Robien Harald Steindl 《Helvetica chimica acta》1985,68(1):231-235
Synthesis and Reactions of the Bicyclo[6.4.0]dodecane-3-carboxylic Acid Derivatives The synthesis and some consecutive reactions of the compounds 5-8 , derivatives of bicyclo[6.4.0]dodecane-3-carboxylic acid ( 1 ), are described. The esters 7 and 8 can be obtained by Baeyer-Villiger oxidation of 2-hydroxy-8-methyltricyclo[7.3.1.02,7]tridecan-13-one ( 4 ) and subsequent hydrolysis of the lactone 5 . The structure and configuration of these compounds has been evaluated by spectroscopic techniques (mainly 2D-NMR methods). The formation of 7 via 1,2-H shift and subsequent isomerization to 8 has been studied. The esters 11 and 13 are formed stereospecifically from 7 and 8 . 相似文献
2.
Tarek A. Salama Abdel-Aziz S. El-Ahl Abdel-Galil M. Khalil Margret M. Girges Bernd Lackner Christian Steindl Saad S. Elmorsy 《Monatshefte für Chemie / Chemical Monthly》2003,20(5):1241-1252
Several new 1-aryl-, aralkyl-, and heteroaryl-5-(4-phenylbuta-1,3-dienyl)tetrazole derivatives and annulated tetrazole derivatives were efficiently and regiospecifically prepared in nearly quantitative yield via a facile one step reaction of dienones with a combination of tetrachlorosilane and sodium azide in acetonitrile under mild conditions. A complete structure assignment of three representative examples of the tetrazoles was achieved by advanced 2D NMR measurements including COSY, TOCSY, HSQC, HMBC, NOESY, and ROESY experiments. 相似文献
3.
Salama Tarek A. El-Ahl Abdel-Aziz S. Khalil Abdel-Galil M. Girges Margret M. Lackner Bernd Steindl Christian Elmorsy Saad S. 《Monatshefte für Chemie / Chemical Monthly》2003,134(9):1241-1252
Summary. Several new 1-aryl-, aralkyl-, and heteroaryl-5-(4-phenylbuta-1,3-dienyl)tetrazole derivatives and annulated tetrazole derivatives were efficiently and regiospecifically prepared in nearly quantitative yield via a facile one step reaction of dienones with a combination of tetrachlorosilane and sodium azide in acetonitrile under mild conditions. A complete structure assignment of three representative examples of the tetrazoles was achieved by advanced 2D NMR measurements including COSY, TOCSY, HSQC, HMBC, NOESY, and ROESY experiments.Received March 17, 2003; accepted March 18, 2003
Published online July 28, 2003 相似文献
4.
In the second part a practically important problem, namely the stability of relative equilibria of a dumbell satellite on an orbit around the Earth is treated by means of the reduced energy-momentum method. The dumbell satellite is used to emphasize the advantages of the reduced energy-momentum method which did not become obvious in the simple example of the rotating pendulum treated in Part I, as well as, to discuss some of the finer technical details. 相似文献
5.
Optimal Control of Deployment of a Tethered Subsatellite 总被引:6,自引:0,他引:6
One of the most important operations during a tethered satellite system mission is the deployment of a subsatellite from a space ship. We restrict tothe simple but practically important case that the system ismoving on a circular orbit around the Earth. The main problem duringdeployment due to gravity gradient is that the two satellites do not move along the straight radial relative equilibrium position which is stable for a tether of constant length. Instead, deploymentleads to an unstable motion with respect to the radial relativeequilibrium configuration. Therefore we introduce an optimal control strategy using theMaximum Principle to achieve a force controlled deployment of the tethered subsatellite from the radial relative equilibrium position close to the space ship to the radial relative equilibrium position far away from the space ship. 相似文献
6.
Alois Steindl 《PAMM》2014,14(1):295-296
We investigate the stabilization of the radial equilibrium of a tethered satellite by tension control, if both in-plane and out-of-plane deviations from the vertical position are taken into account. While in-plane perturbations can be eliminated in finite time, the length rate change of the tether acts as parametric control on the out-of-plane deviations. Therefore the control becomes less effective, if the perturbation decreases. In order to improve the convergence we investigate the optimal control problem assuming no costs for the applied tension force but restricting the control force to a finite interval. For tether cconfigurations close to the vertical target position this approach yields a solution with singular control, which leads to a faster decay of the deviations. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
7.
In this first part of the paper, we review methods for the investigation of stability of relative equilibria of symmetric Hamiltonian systems and explain them by means of the model problem of a rotating pendulum. For this example the modern approaches, known as energy momentum methods are compared with stability assessment by linearization and by the classical method of Routh. 相似文献
8.
The sky-hook, that is a string forming a connection from the surface of the Earth to a satellite in geostationary orbit, which may be used as track for an Earth to space elevator, is an old dream of mankind, originating about 100 years ago in Russia. Besides the question of feasibility from a technological point of view also the question concerning the stability of such a configuration has not yet been completely solved. Under the assumption that a proper material (carbon nanotubes) is available making the connection possible technologically, we address the question of stability of the radial relative equilibrium of a tapered string reaching from the surface of the Earth to a satellite on a circular geosynchronous orbit around the Earth. 相似文献
9.
We investigate the dynamics of a hauling rope modelled as an inextensible completely flexible string and calculate the first natural frequencies. Furthermore we discuss the sensitivity of the model on the operating speed of the ropeway. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
10.
Protein A affinity chromatography is a popular purification method for immunoglobulins applied at various scales, ranging from micro-tube up to 1000l column format. Three novel high capacity protein A affinity chromatography media have been subjected to a lifetime study using 50 consecutive purification cycles of a cell culture supernatant (CCS) containing a monoclonal antibody. Chromatographic conditions followed protocols used in industrial antibody processing, including stripping and cleaning-in-place of the resins. For all three media, no significant loss of purification performance (measured by sodium dodecylsulfate polyacrylamide gel electrophoresis and analytical size-exclusion chromatography (SEC)) could be observed over 50 cycles. Eluate samples were analyzed for leaked protein A and host cell protein (HCP) content. MabSelect SuRe, the first protein A affinity medium compatible with alkaline regeneration conditions, exhibited the lowest leakage levels, in the range of 1-3 ppm. For the media MabSelect Xtra and ProSep-vA Ultra, leakage levels were in the range of 30-40 ppm. Host cell protein content of eluates from MabSelect Xtra and SuRe were between 300 and 700 ppm, whereas for ProSep-vA Ultra 3000-4000 ppm was achieved. 相似文献