Showing papers by "Braunschweig University of Technology published in 1982"
TL;DR: Very high and broad Curie maxima are observed in ceramic Ba(Ti1-yZry)O3 mixed crystals, which are often used for the preparation of ceramic dielectrics as discussed by the authors.
Abstract: Very high and broad Curie maxima are observed in ceramic Ba(Ti1-yZry)O3 mixed crystals, which are often used for the preparation of ceramic dielectrics The ferroelectric-to-paraelectric phase transition of ceramic Ba(Ti1-yZry)O3 was studied using dielectric measurements, quantitative DTA, X-ray diffraction, and determination of the remanent polarization At higher Zr concentrations, it was found that ferroelectric and paraelectric phases coexist in a wide temperature region Up toy =016, the phase transition remains first order The diffuse character is promoted by the small energy difference between the ferroelectric and paraelectric phases appearing at higher Zr content It can be best described by a normal distribution of Curie temperatures using the phenome-nological theory of Devonshire and the Newton-Raphson mathematical approximation
566 citations
TL;DR: In this article, a helios solar probe survey of solar wind helium ion velocity distributions and derived parameters between 0.3 and 1 AU is presented, where the role of Coulomb collisions in limiting differential ion speeds and the ion temperature ratio is investigated.
Abstract: A Helios solar probe survey of solar wind helium ion velocity distributions and derived parameters between 0.3 and 1 AU is presented. Distributions in high-speed wind are found to generally have small total anisotropies, with some indication that, in the core part, the temperatures are greater parallel rather than perpendicular to the magnetic field. The anisotropy tends to increase with heliocentric radial distance, and the average dependence of helium ion temperatures on radial distance from the sun is described by a power law. Differential ion speeds with values of more than 150 km/sec are observed near perihelion, or 0.3 AU. The role of Coulomb collisions in limiting differential ion speeds and the ion temperature ratio is investigated, and it is found that collisions play a distinct role in low-speed wind, by limiting both differential ion velocity and temperature.
396 citations
TL;DR: Lipophilic compounds of the culture suspension containing Rhodococcus erythropolis DSM43215 had surfactant properties when the bacteria were cultivated with n-alkanes as the sole carbon source and the interfacial properties were stabile in solutions with a wide range of pH and ionic strength.
Abstract: Lipophilic compounds of the culture suspension containing Rhodococcus erythropolis DSM43215 had surfactant properties when the bacteria were cultivated with n-alkanes as the sole carbon source. Thirteen main components from a dichloromethane-methanol extract of the R. erythropolis cultures were isolated and characterized to specify quantitatively their surfactant properties, e.g., minimum surface and interfacial tensions and critical micelle concentrations. The interfacial activity of the organic extract was dominated by alpha,alpha-trehalose-6,6'-dicorynomycolates which reduced interfacial tension from 44 to 18 mN/m. Phosphatidylethanolamines which were also present in the organic extract reduced the interfacial tension below 1 mN/m. The trehalose corynomycolates had extremely low critical micelle concentrations in high-salinity solutions, and the interfacial properties were stabile in solutions with a wide range of pH and ionic strength.
203 citations
TL;DR: In this paper, a new interpretation of the habits of ice growing from vapour is proposed, based on a view that the surface of ice just below 0°C is covered with a quasi-liquid layer, whose thickness ϑ or coverage δ decreases with falling temperature, and therefore the growth mechanism of a crystal face changes also as follows.
200 citations
157 citations
143 citations
TL;DR: It is shown that the strong law of large numbers holds also for fuzzy random variables and this result is used to give a consistent estimator for the expectation of a fuzzy random variable.
139 citations
TL;DR: V Voyager 2 crossed the magnetopause of a relatively compressed Saturnian magnetosphere at 18.5 RS while inbound near the noon meridian and throughout the outbound magnetosphere passage, the field was relatively steady and smooth showing no evidence for any azimuthal asymmetry or magnetic anomaly in the planetary field.
Abstract: Results of Voyager 2 studies of the magnetosphere and planetary magnetic field of Saturn are presented. Magnetometer studies have confirmed the results obtained by Voyager 1, indicating the magnetic field to be that of a centered dipole of moment 0.21 gauss Saturn radii-cubed, tilted approximately 0.8 deg from the rotation axis and a maximum measured field intensity of 1187 nT at latitude 17.3 deg N just before periapsis. Voyager 2 observed multiple bow shock and magnetopause crossings during its inbound and outbound trajectories, which were complementary to those of Voyager 1, including magnetopause crossing at 18.5 Saturn radii on the inbound trajectory, and at 48.4-50.9 Saturn radii outbound indicative of magnetospheric expansion due to changing solar wind conditions. Throughout the outbound passage, the magnetospheric field was observed to be relatively steady and smooth, with no evidence for any azimuthal asymmetry or magnetic anomaly. Results thus are incapable of accounting for the observed periodic modulation of the Saturnian kilometric radio emissions.
125 citations
TL;DR: The lower tectonic unit of Ios provides evidence of an at least four stage metamorphic and intrusive history which well might be generalized for large parts of the internal Pelagonian as mentioned in this paper.
Abstract: The lower tectonic unit of Ios provides evidence of an at least four stage metamorphic and intrusive history which well might be generalized for large parts of the internal Pelagonian.
103 citations
TL;DR: A time-optimal solution to the firing-squad-synchronization-problem of n-dimensional rectangles with the general at an arbitrary position is presented and the straightforward generalization to larger n is outlined.
83 citations
TL;DR: In this paper, the effect of temperature on the physical and mechanical properties of typical steels and concretes which are used in PCRV design are presented, and special consideration has been given to the properties and phenomena concerning thermal behaviour, e.g. thermal diffusivity and conductivity, specific heat, density, thermal expansion and decomposition effects.
TL;DR: The main feature of an advanced pressurized water reactor (APWR) with improved fuel utilization is a plutonium-enriched tight lattice core integrated in an unchanged primary system of a common pres...
Abstract: The main feature of an advanced pressurized water reactor (APWR) with improved fuel utilization is a plutonium-enriched tight lattice core integrated in an unchanged primary system of a common pres...
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TL;DR: This survey was initiated by Forrest's article “The twisted cubic curve” and the subsequent correspondence with A. Ball on some minor misunderstandings; some new algorithms can be obtained in a straightforward way.
01 Mar 1982
TL;DR: In this article, the He(II) photoelectron spectra of acrolein, propynal and propynol are interpreted with the aid of ab initio many-body Green's function calculations in the outer and inner valence region.
Abstract: The He(II) photoelectron spectra of acrolein, propynal, propynol and propiolic acid are interpreted with the aid of ab initio many-body Green's function calculations in the outer and inner valence region. Koopmans' approximation fails to supply the correct ordering of electronic states in the radical cation if the lone pair orbital on the oxygen atom is of a′ symmetry. In the case of propynal the ordering of two ionic states o f equal symmetry is interchanged with respect to the Koopmans' orderin. A strong mixing of hole configurations occurs for outer valence states of propynol and propiolic acid. The implications of this mixing are briefly discussed.
TL;DR: Sixteen sterile mutants of Schizosaccharomyces pombe, isolated from homothallic h90strains, were examined and it was found that they are blocked either in copulation and meiosis or inCopulation alone.
Abstract: Sixteen sterile mutants of Schizosaccharomyces pombe, isolated from homothallic h
90strains, were examined. It was found that they are blocked either in copulation and meiosis or in copulation alone. Protoplasts of the sterile strains were fused with protoplasts of h+N, h−S or h
90strains. In these somatic crosses, eight of the sterile strains yielded hybrids which were able to form azygotic asci. Tetrad analyses revealed that seven of these sterile strains contain a single mutation; the mutations represent at least five sterility genes (ste2, ste3, ste4, ste5, ste6). One sterile strain contains two unlinked mutations which do not represent sterility genes, but genes the interaction of which results in a sterile phenotype.
TL;DR: A proposal is made to measure the “efficiency” of cellular algorithms, implemented in cellular automata, roughly speaking by the ratio of the number of proper state changes and the product of time, and number of single automata.
Abstract: A proposal is made to measure the “efficiency” of cellular algorithms, implemented in cellular automata, roughly speaking by the ratio of the number of proper state changes and the product of time, and number of single automata. Such a definition is discussed in some detail. For some cellular algorithms lower bounds for their efficiency are given.
TL;DR: This relation is used to prove some properties of λ-additive fuzzy measures and it is shown that some measures have properties similar to those of positive fuzzy measures.
TL;DR: In this paper, the authors proposed two families of isodynes related to two characteristic directions of a plane stress field and additional redundant information, which can be applied to determine all three stress components in photoelastic models and in original machine or structural parts using isodyne coatings.
Abstract: The term "isodynes" has been proposed by Pindera and Mazurkiewicz to denote a new family of characteristic lines of plane stress fields. These lines carry information on total normal forces acting on related cross sections and yield the distribution and values of related normal and shear stress components. Two families of isodynes related to two characteristic directions yield the values of all three components of a plane stress field and additional redundant information. Isodyne photoelasticity methods can be applied to determine all three stress components in photoelastic models and in original machine or structural parts using isodyne coatings. The term "gradient photoelasticity" has been proposed by Pindera and Hecker to denote a new method of photoelasticity which utilizes relationships between the curvature of light paths in a photoelastic object and the gradients of symmetrical and distortional parts of stress/strain tensors. Utilizing a basic mathematical model of photoelastic effect presented by Ramachandran and Ramaseshan, gradient photoelasticity yields the momentary values of absolute and relative photoelastic coefficients. Both methods can be applied to determine the values of stress intensity factors for arbitrary cracks and all stress components in composite structures.
TL;DR: In this article, it was assumed that both cymrite and celsian were formed at conditions near the reaction curve celsianss+water= cymritess during the Barrovian type event.
Abstract: Manganese-rich rocks from the island of Andros (Cyclades/Greece) contain cymrite (BaAl2Si2O8·H2O) and celsian. The textural relationships indicate replacement of celsian by cymrite. Several microprobe analyses of cymrites show a solid solution of 0.7–6.1 mole% KAlSi3O8·H2O. The relic celsians have similar K contents. Thus the described rocks from Andros represent the first natural example for the reaction celsian+water= cymrite. The rocks from Andros underwent an Eocene high pressure metamorphism. Lateron, the high pressure parageneses were nearly effaced by a Late Oligocene Barrovian type metamorphism. It is assumed that both cymrite and celsian were formed at conditions near the reaction curve celsianss+water= cymritess during the Barrovian type event.
TL;DR: In this paper, the best results were obtained with the system glycerine: HCl ∶ HClO4 for preferential attack of InP and with the System H2O ∵ H2SO4 ∵H2O2 for preferential etching of InGaAsP.
Abstract: Wet chemical etchants are inexpensive and can be employed easily in device fabrication. Material-selective etchants extend the design flexibility for devices with heterostructures. Several etchants on (100) InP and LPE-grown (100) InGaAsP are studied with emphasis on smooth crystal surfaces and well-defined mesa-structures by use of photoresist. The best results are obtained with the system glycerine: HCl ∶ HClO4 for preferential attack of InP and with the system H2O ∶ H2SO4 ∶ H2O2 for preferential etching of InGaAsP. Detailed information is given on the etching solutions investigated, on the etching conditions and the etching rates of the most useful etchants.
TL;DR: In this paper, the vibrational rule structuic of the 2A'1 band in the photoelectron spectrum of BF3 was analyzed using ab initio calculated coupling constants, it was shown that some lines of this spectrum represent excitation of single quanta of the degenerate stretching vibration They borrow their intensity from the adjacent 2E' state via a pseudo-Jahn-Teller interaction
01 Dec 1982
TL;DR: In this paper, the β-endpoint energies of very neutron-rich Rb and Cs isotopes with mass numbers 94≦A≦98 and 142≦ A≦146, respectively, have been measured with a plastic scintillatorβ-telescope at the on-line mass separator OSTIS.
Abstract: Theβ-endpoint energies of very neutron-rich Rb and Cs isotopes with mass numbers 94≦A≦98 and 142≦A≦146, respectively, have been measured with a plastic scintillatorβ-telescope at the on-line mass separator OSTIS. From these,Qβ-values and mass excesses are calculated and compared with the results obtained in direct mass determinations.
TL;DR: In the Precambrian near Morogoro (East Tanzania) there are anatectic gneisses which are composed of two different domains: (1) Medium grained gneses with the assemblage (+ rutile + baddeleyite): albite (ab 95 an 03 or 02 ) + muscovite + phlogopite ss + corundum, and albite(ab 88 an 09 or 03 ) + kyanite or sillimanite+ phlogopeite ss as discussed by the authors.
TL;DR: 6-Aminopenicillanic acid from penicillin V is produced by Pleurotus ostreatus immobilized by entrapment in a chitosan matrix in carriers in which the cell concentration increases after network formation by irreversible shrinking of the biocatalyst.
Abstract: 6-Aminopenicillanic acid from penicillin V is produced by Pleurotus ostreatus immobilized by entrapment in a chitosan matrix. In these carriers the cell concentration increases after network formation by irreversible shrinking of the biocatalyst. Specific activity of the biocatalyst for the hydrolysis reaction is 1,31 μmol.min-1. (g wet weight of catalyst)-1 corresponding to a relative activity of 38%. Catalytic half-life of immobilized Pl. ostreatus is 25 days compared to 2.5 days for free suspended cells.
01 Jan 1982
TL;DR: The intention is to discuss briefly the concepts and some results with reference to more detailed data published elsewhere, as well as to describe some of the experimental results.
Abstract: Within the last two years (1,2) various new methods have been developed related to the preparation and characterization of biocatalysts obtained by polymer entrapment of whole cells. It is the intention to discuss briefly the concepts and some results with reference to more detailed data published elsewhere.
TL;DR: It is shown how to construct fuzzy measures which are compatible with a relative likelihood, and a relation defined on a @s-algebra, called 'relative likelihood', is introduced.
TL;DR: From a semiquantitative examination by TLC of urine extracts from man and rat, it becomes apparent, that in the rat, sulfate formation is the predominant conjugation pathway.
Abstract: A series of six major urinary conjugates in the metabolism of antipyrine in man and rat has been investigated. A preparative isolation procedure has been developed using chromatography of methanolic extracts from urine on silica gel. In a two-step chromatographic procedure, methanolic extracts are first separated in 1) a "free fraction", containing unconjugated phase-I-metabolites and unchanged antipyrine, 2) a sulfate fraction and 3) a glucuronide fraction. Sulfate and glucuronide fraction, respectively, are each subjected to a second run for separation into their three components. Thus, the following conjugates have been prepared: 4-hydroxy-antipyrine sulfate, norantipyrine sulfate, 4,4'-dihydroxy-antipyrine sulfate, and 4-hydroxy-antipyrine glucuronide, norantipyrine glucuronide, 3-hydroxymethyl-antipyrine glucuronide. Methodology is also applicable to bile fluid and liver perfusate. Stability of isolated conjugates against acid hydrolysis has been studied to show that strongly marked differences exist in this series of conjugates. Field desorption mass spectrometry has been used for the direct identification of intact conjugates in an underivatized form. Using 13C-NMR, the structure of norantipyrine glucuronide has been established as an 5-enol glucuronide. By analogy, a structure of 5-enol sulfate is proposed for norantipyrine sulfate. From a semiquantitative examination by TLC of urine extracts from man and rat, it becomes apparent, that in the rat, at the dose level studied, sulfate formation is the predominant conjugation pathway. In man, glucuronides are the most prominent type of conjugates. Formation of sulfates is minimal up to a dose of 15 mg/kg antipyrine.
TL;DR: In this paper, Cope-type rearrangements proceed via diradical intermediates and are formally Cope type rearrangement proceed via Diradical Intermediates.