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  • 1
    Electronic Resource
    Electronic Resource
    A method for checking X-ray diffractometer stability and its application (1987)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 20 (1987), S. 289-294 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: A statistical model of step-scanning of Bragg reflections on an X-ray diffractometer has been suggested [Dietrich (1976). J. Appl. Cryst. 9, 205–208]. A method and software for stability checking of X-ray automatic diffractometers at the user's laboratory have been developed on the basis of this model. The method is an extension of the technique proposed by Dietrich (1976) and reveals the operational instability of the instrument by processing the data of repeated measurements of a reflection intensity profile of a test crystal. The developed software package gives information about the error in initial positioning, the speed instability of the goniometer and the instability of the X-ray source and detector. The method was applied to a number of automatic four-circle X-ray CAD-4 (Enraf–Nonius, Holland) and Syntex (USA) diffractometers. The results obtained indicate that the method has high sensitivity and can be useful for practical crystallographers to reveal defects of their instruments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889887086655
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  • 2
    Electronic Resource
    Electronic Resource
    Crystal-chemical model of atomic interactions. 3. Convex polyhedra with regular faces (1989)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 45 (1989), S. 661-671 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Convex polyhedra with regular faces were used for developing the crystal-chemical model of atomic interactions. Some examples of inorganic crystal structures with coordination polyhedra belonging to convex polyhedra with regular faces are considered. Only four polyhedra - tetrahedron, octahedron, trigonal bipyramid and cube (without due regard for displacement of some atomic groups as a whole) - are shown to be stable at any value of the atomic interaction potential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108767389005027
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  • 3
    Electronic Resource
    Electronic Resource
    Molecular cloning of mycobacterial promoters in Escherichia coli (1989)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 59 (1989), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Mycobacterium bovis BCG chromosomal DNA, digested with EcoR1 and HindIII, was used to construct a promoter library in Escherichia coli using the promoter probe plasmid pKO-1. DNA inserts of various sizes showed promoter activity judged by the level of galactokinase (galK) whose synthesis they activate (between 50 and 850 galactokinase units). No correlation between the lenght of the DNA insert and the level of the galactokinase was found suggesting that the multicopy pool of the promoters does not influence the level of the transcription of the galK gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1989.tb03100.x
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  • 4
    Electronic Resource
    Electronic Resource
    A self-validating numerical method for the matrix exponential (1989)
    Springer
    Computing 43 (1989), S. 59-72 
    Details
    ISSN: 1436-5057
    Keywords: 65G10 ; 65L05 ; 65F30 ; 41A21 ; matrix exponential ; Padé approximations ; iterative defect correction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Es wird ein Algorithmus vorgestellt, der hochgenaue und automatisch verifizierte Grenzen fuer die Exponentialfunktion einer Matrix liefert. Unser Verfahren benuetzt iterative Defektkorrektur, Intervall-Analysis und eine erweiterte Rechnerarithmetik. Der dargestellte Algorithmus basiert auf dem “scaling and squaring” Schema und benutzt Padé-Approximationen und safe-error-monitoring. Es werden ein PASCAL-SC Programm vorgestellt und numerische Resultate diskutiert.
    Notes: Abstract An algorithm is presented, which produces highly accurate and automatically verified bounds for the matrix exponential function. Our computational approach involves iterative defect correction, interval analysis and advanced computer arithmetic. The algorithm presented is based on the “scaling and squaring” scheme, utilizing Padé approximations and safe error monitoring. A PASCAL-SC program is reported and numerical results are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02243806
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  • 5
    Electronic Resource
    Electronic Resource
    On the photochemical behaviour of 1-methyl-4-ethoxycarbonylpyridinium iodide (1988)
    Springer
    Monatshefte für Chemie 119 (1988), S. 1185-1188 
    Details
    ISSN: 1434-4475
    Keywords: 1-Methyl-4-ethoxycarbonylpyridinium iodide ; Reversible photochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Wirkung des Ultraviolettlichtes auf eine methanolisch-wäßrige Lösung von 1-Methyl-4-ethoxycarbonylpyridiniumjodid wurde studiert. Es wurde festgestellt, daß die Belichtung der luftgesättigten Lösung bei 225 nm eine Bildung von Spezies, die bei 358 nm absorbieren, hervorruft. Die Belichtung einer Lösung, die die neugebildeten Partikel enthält, verursacht bei 280 nm einen Rückgang bzw. eine allmähliche Abnahme der Konzentration des gebildeten Komplexes.
    Notes: Abstract The effect of ultraviolet light on a methanol-water solution of 1-methyl-4-ethoxycarbonylpyridinium iodide has been studied. It has been established that the 225 nm irradiation of air-saturated solution initiates the formation of species which absorb at 358 nm. The 280 nm irradiation of a solution containing newly formed particles causes a reverse process of a gradual diminuation of the concentration of the complex formed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00809271
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  • 6
    Electronic Resource
    Electronic Resource
    Tectonics of the Venus and the early Precambrian (1989)
    Springer
    Earth, moon and planets 45 (1989), S. 101-113 
    Details
    ISSN: 1573-0794
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Analyzing the tectonics of planets and their satellites we use all the information available from the studies of the Earth and other celestial bodies such as the Moon, Mars and Mercury. An important condition in such analysis is naturally the scale of the phenomena compared. Most surface structures of Venus are known to have no direct analogues on the surface of the present Earth, with its global systems of mid-oceanic ridges, deep trenches and vast lithospheric plates. This might be due to the sharp differences in the present thermal regimes of the Earth and Venus. It has already been suggested in numerous papers that the key to the genesis of the Cytherean surficial structures must be looked for in the geodynamics of the Early Precambrian Earth. Such an approach appears very logical indeed since the rheology of the present Cytherean crust must be closer to that of the Precambrian rigid lithosphere of the Earth which is as if ‘floating’ in the low-viscous asthenosphere. An attempt has therefore been made to evaluate certain elements in the tectonics of Venus through the theological properties of its crust comparing structural formation in the low-viscous layers of the Earth crust in the Early Precambrian with data on the morphology of structures on the surface of Venus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00055778
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  • 7
    Electronic Resource
    Electronic Resource
    Peculiarities of the formation of the cold intermediate layer in Black Sea regions with various dynamic conditions (1989)
    Springer
    Physical oceanography 1 (1989), S. 121-128 
    Details
    ISSN: 0928-5105
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Hydrological surveys made in 1984–1985 are analysed. In most of the water area the core of the cold intermediate layer (CIL) lies below the critical depth of convection. This reveals the advective nature of the CIL in these regions. Non-linear one-dimensional models provided values of the depth and temperature of the CIL which are close to the real values only in regions of maximum cooling. The hydrodynamic model of the temperature anomaly evolution which can arise in the cyclonic circulation zone confirms the local nature of the anomaly effect. During the last decades, the CIL depth was shallower, but this effect exists only in the outlying areas of the sea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02198022
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  • 8
    Electronic Resource
    Electronic Resource
    Preparation of copper-cobalt oxide spinels by thermal decomposition of copper-cobalt basic nitrate mixed crystals (1985)
    Springer
    Journal of materials science 20 (1985), S. 1211-1214 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Copper-cobalt oxide spinels with a common formula Cu x Co3−x O4 (0≤x≤1.0) have been prepared by thermal decomposition at 350° C in air of single-phase mixed basic nitrate precursors (Cu, Co)2(OH)3NO3. The formation of the oxide phase during the thermal treatment has been associated with a diffusionless mode of transformation, established for some hydroxides and hydroxysalts with a layer-type structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01026316
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  • 9
    Electronic Resource
    Electronic Resource
    Crystallization kinetics of the amorphous alloy Fe80B20 studied using a thermomagnetic balance (1986)
    Springer
    Journal of materials science 21 (1986), S. 2553-2556 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The kinetics of isothermal crystallization of the amorphous metal alloy Fe80B20 have been studied using a Perkin-Elmer thermomagnetic balance. Well-defined and reproducible incubation periods were observed on the degree of crystallization against time curves, in agreement with the theory of non-steady state nuclear ions in glasses. Values from 1.4 to 2.4 were obtained for the exponentn in the Johnson-Mehl-Kolmogorov-Avrami equation. The activation energy of viscous flow in the glass was found from the incubation period against temperature dependences at temperature near the crystallization point. The activation energy of crystallization was determined from the temperature dependence of the 50% crystallization times. Metallographic observations show unambiguously that two crystallization reactions proceed simultaneously: the growth of ready athermal centres located on the more slowly quenched surface of the amorphous metal ribbon along two directions, and growth in the bulk of the ribbon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01114306
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  • 10
    Electronic Resource
    Electronic Resource
    Zinc-cobalt oxide spinels with precursor-controlled degree of inversion (1988)
    Springer
    Journal of materials science 23 (1988), S. 181-184 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Zinc-cobalt oxide spinels, ZnCo2O4, have been prepared by thermal decomposition of three different precursors: (I) coprecipitated zinc-cobalt hydroxide nitrate; (II) coprecipitated zinc-cobalt hydroxide, and (III) zinc-cobalt hydroxide nitrate prepared by isomorphous replacement of the tetrahedrally coordinated Co2+ ions in the double-layered parent cobalt hydroxide nitrate by Zn2+ ions. It has been shown that the cationic distribution in the oxide product is predetermined by the cationic distribution of the precursor. The coprecipitated precursors (I) and (II) decompose to statistical spinels, whereas precursor (III) decomposes to a normal Zn [Co2]O4 spinet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01174050
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