ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
    ISSN: 1573-1111
    Keywords: Calix[4]arene ; aluminum alkyl ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The configurations of calix[4]arenes may be modified by the formation of donor-acceptor complexes which make use of the basicity of the oxygen atoms of the macrocycle. The complex [t-butylcalix[4]arene methyl ether][AlMe3]2,2, exhibits the previously unseen ‘1,2-alternate’ geometry, while [t-butylcalix[4]arene methyl ether][MeAlCl2]2,3, and [t-butylcalix[4]arene methyl ether][EtAlCl2]2,4, show the ‘1,3-alternate’ configuration.2 crystallizes in the triclinic space groupPl witha=11.14(1),b=11.60(1),c=12.02(1) Å, α=77.32(8), β=67.91(8), and γ=69.34(8)o withD c =1.06 g cm−3 forZ=1. Refinement based on 1270 observed reflections led toR=0.106.3 as the benzene solvate belongs to the monoclinic space groupC2/c witha=12.116(2),b=21.557(7),c=23.470(6) Å, and β=104.05(2)o withD c =1.13 g cm−3 forZ=4. Refinement based on 2335 observed reflections led toR=0.075.4 crystallizes in the monoclinic space groupC2/c witha=12.062(4),b=21.175(6),c=21.596(5) Å, and β=100.78(4)o withD c =1.18 g cm−3 forZ=4. Refinement based on 2529 observed reflections gaveR=0.082. The Al-O lengths in all three complexes are normal for donor-acceptor interactions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-1111
    Keywords: Calix[4]arene ; crystal structure ; clay mineral ; alkali metal ion ; layered structure ; water soluble ; sulfonate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The title calixarenes all exist in the solid state as bilayers of anionic calixarenes in the cone configuration. These layers alternate with inorganic regions which contain the cations and the water molecules. The overall structures bear a close resemblance to those found for clay minerals. The sodium salt crystallizes in the triclinic space groupPĪ witha = 10.998(6),b = 13.582(5),c = 14.472(5) Å,α = 74.01(3),β = 89.09(4),γ = 86.50(4)°, andZ = 2 forD calc = 1.72 g cm−3. Refinement based on 4727 observed reflections led to a conventionalR = 0.050. The potassium salt crystallizes in the triclinic space groupPĪ witha = 11.815(9),b = 13.636(6),c = 14.040(9) Å,α = 100.24(5),β = 111.86(9),γ = 95,14(9)°, andZ = 2 forD calc = 1.77 g cm−3. Refinement based on 2977 observed reflections led toR = 0.15. The rubidium and cesium salts are isostructural and crystallize in the monoclinic space groupP21/n with parameters for Rb[Cs]a = 11.603(5) [11.704(3)],b = 28.607(8) [29.747(9)],c = 12.512(5) [12.604(4)] Å,β = 91.70(4) [91.63(2)°], andZ = 4 forD calc = 2.01 [2.24] g cm−3. Refinement based on 1750 [4257] observed reflections led toR = 0.108 [0.075]. Disorder of the cations was observed for the rubidium and cesium salts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2019-07-12
    Description: The design of self-tuning controllers for multivariable stochastic systems is considered analytically. A long-division technique for finding the similarity transformation matrix and transforming the estimated left MFD to the right MFD is developed; the derivation is given in detail, and the procedures involved are briefly characterized.
    Keywords: CYBERNETICS
    Type: Stochastic Analysis and Applications (ISSN 0736-2994); 6; 1 19
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2019-07-12
    Description: Based on the Newton-Raphson method, this paper presents recursive algorithms that are rapidly convergent and more stable for modeling the equivalent continuous-time (discrete-time) model from the available discrete-time (continuous-time) model for a fixed sampling period. The newly developed recursive algorithms relax the constraints imposed upon the existing model conversion algorithms, and, thus, enhance the applications of microprocessors and associated microelectronics to digital control systems. A practical example is presented to demonstrate the effectiveness of the proposed procedures.
    Keywords: CYBERNETICS
    Type: AD-A211074 , Computers and Mathematics with Applications (ISSN 0097-4943); 14; 8 19
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...