Ueber Arbeiten betreffend die Depressionserscheinungen der Thermometer

Ohne Zusammenfassung     

Hydrophobic Silica Sol Coatings on Textiles—the Influence of Solvent and Sol Concentration

Hydrophobic silica sol coatings on textiles were investigated with respect to the influence of the solvents and the concentration of the sol. For this purpose, two silica sols, prepared with the hydrophobic additives octyltriethoxysilane and perfluoroctyltriethoxysilane were diluted by different solvents: water, ethanol and aceton.In case of using pure water for dilution, the hydrophobicity of coated textiles decreases drastically with increasing dilution of the applied sol. For coatings on polyester fabrics or mixed fabrics made from polyester and cotton, the use of the organic solvents ethanol or aceton leads to significant hydrophobicity even in case of strong dilution down to a sol concentration < 1%. The hydrophobic effect of coated polyamide textile is less. The reason for different hydrophobicity of coated textiles resulting from the use of water instead of organic solvents is explained by different surface morphologies of the coatings deposited on the textile fibres, as observed by REM. In case of using organic solvents the coatings contain a more flat morphology which covers the fibres completely. In contrast, sols with higher water content lead to less adhesive coatings with crack formation.The use of a combination of water with less inflammable organic solvents such as di(propylene glycol) n-propyl ether (Dowanol^TM DPnP) in hydrophobic silica sols yields textile coatings with good hydrophobicity, even in case of low sol concentration. For practical application of textile coatings, especially silica sols with high water content are of interest, due to less risk of inflammation and lower ecological impact. Therefore, the use of water diluted hydrophobic silica sols with small amounts of DPnP offers a chance for textile refinement by the sol–gel technique.     

Darstellung und Kristallstruktur von Ca5Hg3 und Sr5Cd3

Preparation and Crystal Structure of Ca₅Hg₃ and Sr₅Cd₃ Both the incongruently melting compounds, Ca₅Hg₃ and Sr₅Cd₃, have been synthesized from stoichiometric amounts of the pure elements. They crystallize with the Cr₅B₃ type of structure: space group I4/mcm, Z = 4; Ca₅Hg₃ (Sr₅Cd₃): a = 818.9(1) (871.7(1)) pm, c = 1 470.1(3) (1 660.1(3)) pm, c/a = 1.80 (1.90), R = 2.33% (2.97%). The most remarkable fragments are dumbbells X₂, which have interatomic distances only slightly longer than the sum of Pauling's covalent radii: Hg? Hg (Cd? Cd) = 306 (298) pm. The structure can be constructed by rhombic dodecahedra as the only constituent moieties. These rhombic dodecahedra are built up by eight Ca (Sr) atoms and six Hg (Cd) atoms and are furthermore centered by an additional Ca (Sr) atom. Along [001] the rhombic dodecahedra share common vertices, but along [110] they are interconnected via common triangular faces. This kind of face sharing is responsible for the short distances obtained between the polyhedra, which leads to the occurrence of the dumbbells mentioned above.     

13C and 14N ENDOR study on Copper(II)/Nickel(II) bis-(diethyl-dithiocarbamate) Cu/Ni(et2dtc)2

The ¹³C and ¹⁴N ENDOR spectra of Cu(et₂dtc)₂ substituted into single crystals of Ni(et₂dtc)₂ are reported. The centrosymmetric, planar structure of the host molecule has been retained by the guest. Comparison between the ¹³C ENDOR data obtained for Cu/Ni(et₂dtc)₂ and Cu/Zn(et₂dtc)₂ has been made considering the different structures of the et₂dtc complexes of Cu, Ni and Zn.     

Hexafluoroacetone as Protecting and Activating Reagent. Glycosylated Malic, Citramalic, and Thiomalic Acid Derivatives, New Glycosylated Building Blocks for Drug Design [1]

Summary. Glycosylated -hydroxy and -mercapto acids have been synthesized starting from malic/citramalic/thiomalic acid and Ac₄--D-Glc-NH₂/Bzl₄--D-Glc-NH₂ using hexafluoroacetone as protecting and activating reagent.Dedicated to Prof. Dr. Horst Wilde on the occasion of his 65^th birthday     

Darstellung und Kristallstruktur von SnTl4Se3 mit einer Anmerkung zu TlSe

Preparation and Crystal Structure of SnTl₄Se₃ with a Note on TlSe We describe the preparation and crystal structure of SnTl₄Se₃. It crystallizes as a low symmetric distorted derivative with the In₅Bi₃ type of structure, which itself should be considered as a subfamily of the Cr₅B₃ type of structure: a = 852.2(2) pm, c = 1 272.2(6) pm, c/a = 1.49, Z = 4. Short Sn? Se distances of 311 pm, and 326 pm, respectively, are obtained in [SnSe_2/2] chains running along [001]. Furthermore, short Tl? Se distances are found in quasimolecular bent moieties Tl₂Se: 300 pm, 313 pm, and 347 pm, respectively. SnTl₄Se₃ is a semiconductor. The conductivity of some closely related phases are also reported. Finally, the structure of the well known compound TlSe has been refined for the first time, in order to get some more information about Tl¹⁺? Se distances for square-antiprismatic coordinated Tl¹⁺ ions.     

Influence of multiplicity and kinematical cuts on Bose-Einstein correlation inπ + p at 250 GeV/c

The correlation of negative particles at small momentum difference and its dependence on multiplicity and on kinematical cuts is studied in ⁺ p-interactions at 250 GeV/c. In terms of the Kopylov-Podgoretski parametrization, an average radius of the pion emitting region ofr _K =1.59±0.14 fm and a life-time (or emission depth) =0.83±0.25 fm are found. The Lorentz invariant parametrization of Goldhaber givesr _G =0.85±0.04 fm. Assuming two different sources of pions, their radii are estimated asr ₁=1.75±0.25 fm andr ₂=0.60±0.08 fm. An angular and multiplicity dependence of the space-time size of the source is observed. The source is elongated along the collision axis and has larger sizer _K at higher multiplicities. The radiusr _K decreases with increasing pion pair momentum. The size of the emitting region appears to be larger for low rapidity pions than for pions from the fragmentation region. No evidence is found for a unique reference frame, where the pion source is motionless for each ⁺ p collision, i. e. where the space-time size of the source is definitely smaller than in any other frame.Partially supported by grants from CPBP 01.06 and 01.09.