Showing papers by "Braunschweig University of Technology published in 1981"
TL;DR: Data from the very close flyby at Titan showed an absence of any substantial intrinsic satellite magnetic field, but results did indicate a very well developed, induced magnetosphere with a bipolar magnetic tail.
Abstract: Confirmation and refinement of Saturnian magnetosphere features established by the Pioneer 11 emission are claimed for Voyager 1 magnetic field studies of the planet. The radius of the magnetopause at the subsolar point is 23 Saturn radii, and a magnetic tail of 80 Saturn radii diameter was discovered. The tail extends away from the sun and is similar to both type II comet tails and the terrestrial and Jovian magnetic tails. Data from Voyager's very close flyby of Titan, which is located within the Saturn magnetosphere, shows an absence of any substantial, intrinsic satellite magnetic field.
217 citations
TL;DR: The knowledge level revealed for young children contrasts sharply with results from previous studies using Piagetian choice tasks, which apparently investigate selective attention to one dimension rather than conceptual understanding of relations.
138 citations
01 Jun 1981
TL;DR: Theoretical studies in the intensity-borrowing sudden approximation of inner-valence-shell photoionization cross sections in N2 and CO are reported in this article, where the required ionic-state energies and spectroscopic amplitudes are obtained from appropriate Green's-function and configuration-interaction calculations, and previously devised Stieltjes-Tchebycheff moment-theory techniques are employed in determinations of corresponding continuum dipole transition moments in the static-exchange approximation.
Abstract: Theoretical studies in the intensity-borrowing sudden approximation are reported of inner-valence-shell photoionization cross sections in N2 and CO. The required ionic-state energies and spectroscopic amplitudes are obtained from appropriate Green's-function and configuration-interaction calculations, and previously devised Stieltjes-Tchebycheff moment-theory techniques are employed in determinations of corresponding continuum dipole transition moments in the static-exchange approximation. Comparisons are made of the Green's-function calculations in the two-particle-hole Tamm-Dancoff approximation with wavefunction results obtained from single-excitation and polarization configuration-interaction calculations. Detailed descriptions are given of the calculated spectroscopic intensity distributions and of the hole-particle configurational compositions of the corresponding inner-valence-shell ionic states. and comparisons are made with previously reported wavefunction studies in N2+ and CO+. Spectroscopic assignments are suggested on basis of the present calculations for the strong features observed recently in higher-resolution inner-valence-shell photoelectron spectra. The corresponding calculated partial-channel photoionization cross sections for the designated C2Σg+, F2Σg+, G2Σg+, and (2σg−1)2Σg+ bands in N2 and C2Σ+, D2Π, F2Σ+, G2Σ+, and (3σ−1)2Σ+ bands in CO are found to be in good quantitative accord with dipole (e, 2e), (e, e + ion), and synchrotron-radiation studies.
119 citations
TL;DR: In this article, the authors examined the structure of the interplanetary sector boundaries observed by Helios 1 within sector transition regions during the time interval from December 1974 to April 1975 and found that the transition regions are complex in character, consisting of intermediate average field orientations in some cases as well as a number of largeangle directional discontinuities (DDs).
Abstract: The study examines the structure of the interplanetary sector boundaries observed by Helios 1 within sector transition regions during the time interval from December 1974 to April 1975. The transition regions are found to be complex in character, consisting of intermediate average field orientations in some cases as well as a number of large-angle directional discontinuities (DDs). It is suggested that the observed DDs represent multiple traversals of the global heliospheric current sheet caused by local fluctuations in the position of the sheet. There is evidence that such fluctuations are sometimes produced by wavelike motions or surface corrugations of scale length 0.05-0.1 AU, superimposed on the large-scale structure.
105 citations
TL;DR: This work has shown that the well-known algorithm by de Boor for calculating a point of a B-spline curve can also be used to produce the Bezier points of aB-splines curve or surface.
Abstract: The well-known algorithm by de Boor for calculating a point of a B-spline curve can also be used to produce the Bezier points of a B-spline curve or surface.
89 citations
TL;DR: In this article, the uppermost unit of the Cretan nappe system consists of ophiolites on the top, and an Ophiolitic melange at the base.
Abstract: The uppermost unit of the Cretan nappe system consists of ophiolites on the top, and an ophiolitic melange at the base. Among the various constituents of the melange, there are slices of low-P/high-T metamorphics. They form a variegated series consisting of tholeiitic ortho-amphibolites, para-amphibolites, andalusite and sillimanite-cordierite-garnet bearing mica schists, calcsilicate rocks, and marbles. The metamorphic sequence is locally intruded by early tectonic magmatites of gabbroic, dioritic and granitic composition. Critical mineral assemblages lead to a maximum temperature of about 700° C reached during metamorphism, at a total pressure of 4–5 kilobars. K — Ar dating on 6 hornblendes, 7 biotites and 1 muscovite yielded cooling ages of 75–66 m.y. and confirmed earlier results according to which the metamorphism and related magmatism took place in Late Cretaceous times. In order to evaluate the age relationships between the hightemperature metamorphics within the ophiolitic melange and the ophiolites, hornblendes from ultramafic and mafic rocks of the ophiolite complex were dated by the K — Ar method. Hornblende from one schistose hornblendite forming a constituent of the ophiolites proper yielded 156 m.y. and thus provides a middle Jurassic minimum age for the formation of this piece of oceanic lithosphere. Four hornblendes of calc-alkaline gabbrodiorite dikes within the ophiolite complex gave distinctly lower K — Ar dates of about 140 m.y.. The dikes probably intruded after the detachment of the ophiolites in an island-arc or continental-margin environment. As a consequence, the high-temperature metamorphics and related intrusives in the ophiolitic melange of Crete are genetically unrelated to the overlying ophiolites. The paleogeographic position of the crystalline terrane, slices of which are now incorporated into the ophiolitic melange is still open to discussion.
80 citations
TL;DR: In this paper, the ionization spectra of the entire valence region are calculated for HF, HCl, HBr and HI, for the two ionization processes of lowest energy, whereas this picture breaks down for ionization from the inner valence α-orbital.
62 citations
59 citations
TL;DR: Microbial cells were immobilized in polyurethane foam as well as polyUREthane gel using liquid hydrophilic polyisocyanates which react with only the addition of water to achieve biocatalytic activity.
Abstract: Microbial cells were immobilized in polyurethane foam as well as polyurethane gel using liquid hydrophilic polyisocyanates which react with only the addition of water. Cell concentration is about 10% (w/v) and relative activity is about 50% depending on the type of biocatalytic reaction.
55 citations
TL;DR: In this article, the effects of isotope fractionation and exchange processes in the snow cover on the isotopic outflow concentrations were investigated in cold room experiments with isotopically homogeneous and stratified snow columns.
Abstract: Stable environmental isotope techniques contribute to reasonable separations of the direct runoff component in snowmelt hydrographs. For the separation procedure, the actual isotope input from snow cover outflows is required. In order to study the effects of isotope fractionation and exchange processes in the snow cover on the isotopic outflow concentrations several cold room experiments have been carried out with isotopically homogeneous and stratified snow columns. To simulate natural conditions the columns were treated with different heat supply and rainwater at the surface, and the outflows analysed for 2 H and 18 O contents. Some fundamental results are discussed with respect to the more complex natural situation. Finally, the hydrological application of such experience is demonstrated for a natural environment.
52 citations
TL;DR: The high rates of methanol degradation measured indicated that the immobilization technique preserved the cellular functions of this methanogenic bacterium.
Abstract: Whole cells of the methanogen Methanosarcina barkeri were immobilized in an alginate network which was crosslinked with Ca2+ ions. The rates of methanol conversion to methane of entrapped cells were found to be in the same range as the corresponding rates of free cells. Furthermore, immobilized cells were active for a longer period than free cells. The particle size of the spherical alginate beads (1.2 mm-3.7 mm ϕ) and thus diffusion had no obvious influence on the turnover of methanol. The half-value period for methanol conversion activity determined in a buffer medium was approximately 4 days at 37°C for entrapped cells. The apparent Km value K for such cells was nearly 140mM and the Vmax value was about 1.2 μmol methanol/min/mg entrapped protein. Therefore the high rates of methanol degradation measured, e.g., 0.5 μmol methanol/min/mg entrapped protein, indicated that the immobilization technique preserved the cellular functions of this methanogenic bacterium.
TL;DR: These experiments demonstrate that the microbial cells are entrapped in the polymer matrix in the living state as well as demonstrating the kinetics of oxidative phenol degradation with microbial cells.
Abstract: The kinetics of oxidative phenol degradation with microbial cellsCandida tropicalis, immobilized in a polyacrylamide and polymethacrylamide matrix, were mathematically simulated assuming zero-order and Michaelis-Menten rate equations. For zero-order kinetics an expanded equation for catalytic effectiveness as a function of the Thiele modulus, Biot number, and partition coefficients was derived and compared with numerical solutions for Michaelis-Menten kinetics. Errors with regard to the zero-order approximation become negligible ifc
o/K
M
>2. Experimentally determined catalyst activities as a function of particle size and cell concentration were compared to calculated ones. Additional experiments to determine the diffusion and oxygen consumption ratios have been carried out in an effort to resolve the physical parameters to be used in the above mentioned calculations. Furthermore, experiments on cell growth during reincubation with nutrients and oxygen are reported; an increase in activity up to a factor of ten was observed. These experiments demonstrate that the microbial cells are entrapped in the polymer matrix in the living state.
TL;DR: The 30.4 nm He(II) photoelectron spectra of the fluorosubstituted ethylenes have been recorded and an unambiguous interpretation of the spectra can be established from empirical considerations alone as discussed by the authors.
TL;DR: In this paper, the remainder of interpolatory quadrature formulae is compared with the Gauss type and the Clenshaw-Curtis quadratures, and it is shown that the latter are the worst.
Abstract: In this paper we study the remainder of interpolatory quadrature formulae. For this purpose we develop a simple but quite general comparison technique for linear functionals. Applied to quadrature formulae it allows to eliminate one of the nodes and to estimate the remainder of the old formula in terms of the new one. By repeated application we may compare with quadrature formulae having only a few nodes left or even no nodes at all. With the help of this method we obtain asymptotically best possible error bounds for the Clenshaw-Curtis quadrature and other Polya type formulae.
Our comparison technique can also be applied to the problem of definiteness, i.e. the question whether the remainderR[f] of a formula of orderm can be represented asc·f (m)(?). By successive elimination of nodes we obtain a sequence of sufficient criteria for definiteness including all the criteria known to us as special cases.
Finally we ask for good and worst quadrature formulae within certain classes. We shall see that amongst all quadrature formulae with positive coefficients and fixed orderm the Gauss type formulae are worst. Interpreted in terms of Peano kernels our theorem yields results on monosplines which may be of interest in themselves.
TL;DR: In this article, the 13C-NMR spectra of 20 cyanogenic glycosides have been measured in deuterium oxide and the potential of this method for characterizing and identifying this type of compound is demonstrated.
Abstract: 13C-NMR spectra of 20 cyanogenic glycosides have been measured in deuterium oxide. These compounds constitute representative examples of four groups of glycosides, namely the butyronitrile, propionitrile, mandelonitrile and cyclopentenoncyanohydrin glycosides. The well resolved signals in the proton-decoupled 13C-spectra are assigned and the potential of this method for characterizing and identifying this type of compound is demonstrated. The subtle effects upon the shifts caused by configuration change in the aglycon moiety are demonstrated to be of use in determining absolute configurations.
13C-NMR-spektroskopische Untersuchungen der Struktur von Cyanglykosiden
Die 13C-NMR-Spektren von 20 cyanogenen Glykosiden, die alle vier Glykosidgruppen, die Butyronitril-, Propionitril-, Mandelsaurenitril- und Cyclopentenoncyanhydringlykoside reprasentieren, wurden in Deuteriumoxid aufgenommen. Die gut aufgelosten Signale der protonenentkoppelten 13C-Spektren wurden zugeordnet und die Moglichkeiten der Methode zur Charakterisierung und Identifizierung von Verbindungen dieser Naturstoffklasse verdeutlicht. Zudem konnte gezeigt werden, das die geringen Unterschiede in den chemischen Verschiebungen, die auf einer Konfigurationsanderung im Aglykon beruhen, sich zur Bestimmung der absoluten Konfiguration heranziehen lassen.
01 Jan 1981
TL;DR: The relation of the simplest class — i.e. the one with a constant number of changes per single automaton — to the Chomsky hierarchy is investigated and a comparison with sequential tape complexity is made.
Abstract: On Cellular Automata with a Finite Number of State Changes. The number of state changes is introduced as a complexity measure for the recognition of languages in cellular automata. The relation of the simplest class — i.e. the one with a constant number of changes per single automaton — to the Chomsky hierarchy is investigated and a comparison with sequential tape complexity is made.
TL;DR: Tracer experiments give evidence that one multiple form, which is responsible for the bulk activity in senescent leaves, is synthesized before, but not after the onset of senescence, indicating that pre-existing latent phenolase is converted to easily activating forms.
TL;DR: In this article, a special configuration interaction approach for the ionic states of open-shell molecules with a spatially nondegenerate ground state is presented, which takes into account all genuine one-hole and two-hole-one-particle excitations with respect to the ground state and allows for the determination of ionic energies and relative intensities for the whole energy range.
TL;DR: In this paper, a comparison of the frequencies and halfwidths of v1 in a variety of solvents showed that dispersion forces make a significant contribution to the effective intermolecular potential.
TL;DR: In this paper, the ionization spectra of ZnCl2, CdCl2 and NiCl2 were calculated by two Green's function methods and the ionisation potentials obtained for the outer valence orbitals were in very good agreement with the experimental values.
Abstract: The ionization spectra of ZnCl2, CdCl2 and NiCl2 are calculated by two Green's function methods. The ionization potentials obtained for the outer valence orbitals are in very good agreement with the experimental values. The spectra of ZnCl2 and CdCl2 consist of three well separated groups of lines. The first group is due to the outer valence orbitals which have mainly metal s and chlorine p character. The metal d electrons constitute the second group and the inner valence chlorine s orbitals dominate the last group. In NiCl2 the metal d electrons participate strongly in the chemical bonding and give rise to strong correlation effects. We find surprisingly low lying satellite lines as well as other satellite lines all over the spectrum. Furthermore, an interesting correlation-induced splitting into two main components approximately 8 eV apart is found for both of the 1π g and 1δ g orbitals. For all three molecules a breakdown of the molecular orbital picture of ionization is predicted for the inner valence...
TL;DR: In this paper, the development of methodical design techniques is discussed, in particular the use of design catalogues of standard parts and subfunctions, and various techniques are discussed.
TL;DR: The RDBM consists of a quasi-associate mass store together with a system of special function processors with common access to a large main memory, and a general purpose mini-computer exercising overall control over all hardware components.
01 Jun 1981
TL;DR: In this paper, the valence shell binding energy spectrum of carbonyl sulphide (10 − 45 eV) was measured using both binary (e,2e) and dipole electron impact spectroscopy and calculated by the 2ph-TDA many body Green's function technique.
TL;DR: In this article, a full scale aerated lagoon system was used to treat leachate of the sanitary landfill in Lingen/West Germany, and the obtained data was evaluated with regard to final BOD5 effluent values dependent on the organic load.
TL;DR: In this paper, the flow stress was measured on recrystallized zinc with pronounced texture for grain sizes from 0,6 to 502 μm, both parallel and perpendicular to the rolling direction.
TL;DR: In this paper, the rotational diffusion model is used to predict the correlation functions for the degenerate (E) bands of liquid acetonitrile (CH3CN) and gas phase Raman band profiles.
TL;DR: In this paper, theoretical and experimental results obtained with germanium exposed to Lorentz field strengths of up to 20000 TV/m (or B ≦ 10 T) at 400 K were presented.
Abstract: A local variation in carrier concentration occurs in intrinsic semiconductors in the presence of crossed electric and magnetic fields which leads partly to an enhancement (“compression”) and partly to a depletion. In connection with these displacements from thermal equilibrium luminescent radiation can be observed which, when related to the thermal radiation under equilibrium conditions, is positive in enhanced and negative in depleted regions. The luminescent radiation spectrum in the region of the fundamental absorption edge is directly related to the free carrier concentration profile in the sample. The report deals with theoretical and experimental results obtained with germanium exposed to Lorentz field strengths of up to 20000 TV/m (or B ≦ 10 T) at 400 K. Non-linear surface recombination must thereby be allowed for. The corresponding semiconductor parameters are given. The modulated galvanomagnetic luminescence exhibits the expected antiphase component at longer wavelengths, corresponding to an increase in the separation of the quasi fermi level from the band edges for constant lattice and electron temperatures.
Bei eigenleitenden Halbleitern tritt in gekreuzten elektrischen und magnetischen Feldern („orentz-Feld”) eine ortsabhangige Tragerdichteanderung ein, die teils zu einer Anreicherung („Kompression”) teils zu einer Verarmung fuhrt. Im Zusammenhang mit diesen Abweichungen vom thermischen Gleichgewichtszustand tritt eine Lumineszenzstrahlung auf, die, bezogen auf die Temperaturstrahlung als Gleichgewichtsstrahlung in den Anreicherungsgebieten positiv, in den Verarmungsgebieten negativ ist. Das Spektrum der Lumineszenzstrahlung im Bereich der Absorptionskante steht mit dem Dichteprofil der freien Trager in der Probe in einem eindeutigen Zusammenhang. Es wird uber theoretische und experimentelle Ergebnisse am Germanium berichtet, das bei 400 K Lorentzfeldstarken bis zu 20000 TV/m (bzw. B ≦ 10 T) ausgesetzt ist, Dabei mus mit einer nichtlinearen Oberflachenrekombination gerechnet werden. Die Halbleiter-parameter werden entsprechend angegeben. Das modulierte Spektrum der galvanomagnetischen Lumineszenz zeigt im langwelligeren Teil den erwarteten gegenphasigen Anteil, der bei konstanter Gitter- und Elektronentemperatur einer Distanzvergroβerung der Quasiferminiveaus zu den Bandrandern entspricht.
TL;DR: The main tools of the method are calculation of edge intersections, test on appearance or disappearance of edges, and record sort, which is short enough to handle scenes of high complexity.
Abstract: A new approach to the hidden-line problem is presented. The main tools of the method are calculation of edge intersections, test on appearance or disappearance of edges, and record sort. Special treatment of coherence and singularities is required. The programs are written in FORTRAN and are very short and simple. The computation time of the algorithm is short enough to handle scenes of high complexity.