Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Determination of Positions of Zeolitic Calcium Atoms and Water Molecules in Hydrothermally Formed Aluminum-Substiqtuted Tobermorite-1.1nm Using Synchrotron Radiation Powder Diffraction Data (2001)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 84 (2001), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The crystal structure of hydrothermally formed Al-substituted tobermorite-1.1nm (Ca4.9Si5.5Al0.5O16.3(OH)0.7·5H2O) has been analyzed using synchrotron radiation powder diffraction data. Crystallographic positions of a zeolitic Ca atom and three water molecules in the channel of the framework were determined by the Monte Carlo method and subsequent Rietveld refinement. The Ca atom splits into two sites at a distance of 0.161 nm apart, and it is coordinated with the three water molecules and the three oxygen atoms belonging to the framework. Al atoms preferably substitute a part of the Si atoms at the “bridging SiO4” tetrahedra rather than at those of the “chain middle group SiO4” tetrahedra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2001.tb01071.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Crystallographic Data of a New Phase of Dicalcium Silicate (1998)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 81 (1998), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Unit-cell parameters and the space group of a new phase of dicalcium silicate (Ca2SiO4) were determined by using powder X-ray diffractometry and selected-area electron diffraction techniques. This phase could be synthesized via the dissociation of hydrothermally synthesized alpha-Ca2(SiO4H)OH at temperatures of ∼500°-920°C. Crystallographic data for the sample synthesized at 600°C were as follows: Ca2SiO4, monoclinic; P21/c space group; lattice parameters of a= 0.82147(9) nm, b= 0.9808(1) nm, c= 0.9741(1) nm, and β= 94.642(7)°; cell volume (V) of 0.7857(1) nm3; Z= 8 (where Z is the number of chemical formula units in a unit cell); and a density of 2.91 g/cm3. The crystallographic data for samples synthesized at 800°C had slightly different unit-cell parameters of a= 0.82124(6) nm, b= 0.97348(7) nm, c= 0.97935(7) nm, β= 94.831(5)°, and V= 0.7849(1) nm3. Structural relationships of the new phase with the other dicalcium silicates are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1998.tb02487.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Ab initio structure determination of monoclinic 2,2-dihydroxymethylbutanoic acid from synchrotron radiation powder diffraction data: combined use of direct methods and the Monte Carlo method (2001)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 57 (2001), S. 184-189 
    Details
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The crystal structure of 2,2-dihydroxymethylbutanoic acid (C6H12O4) in monoclinic form has been determined ab initio from synchrotron radiation powder diffraction data. Two O and five C atoms were first derived by direct methods. Two missing O atoms and one C atom were found by the Monte Carlo method without applying constraint to their relative positions. Positional and isotropic displacement parameters of these non-H atoms were refined by the Rietveld method. Molecules are linked by hydrogen bonds and they make sheet-like networks running parallel to the (010) plane. The Monte Carlo method is demonstrated to be a powerful tool for finding missing atoms in partially solved structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108768100018905
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Thermal behavior of amide substituted diacetylenes (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 1853-1862 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diacetylenes substituted with various amide groups were prepared and their solid-state polymerization behavior was studied. A calorimetric study of the isothermal polymerization of 1,6-diacetylamino-2,4-hexadiyne was performed in detail. This compound has an extremely high reactivity. The reaction proceeded very quickly and the ultimate conversion reached over 40% slightly above room temperature. The feature of the reaction resembles those observed in the solid-state polymerization of other diacetylene compounds, i.e., the reaction proceeds slowly in the initial stage, but the rate of reaction increases drastically at about 5% conversion to polymer. Quantitative conversion, however, was not attained at any temperature, and the reaction leveled off within 1.5 h. It is assumed that the reaction cannot continue owing to the distortions generated in the crystals during the polymerization process. The crystalline state of the polymer obtained was highly disordered.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080270606
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...