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
Filter
  • Chemistry  (122)
  • 51  (2)
  • 71.55.Fr  (2)
  • Detergents  (2)
  • 1
    Electronic Resource
    Electronic Resource
    SANS-measurements on micellar solutions of perfluoro-detergents (1982)
    Springer
    Colloid & polymer science 260 (1982), S. 435-443 
    Details
    ISSN: 1435-1536
    Keywords: Detergents ; Micelles ; Short Range Order ; Neutron Scattering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Small-angle-neutron-scattering-(SANS)-measurements were carried out with soulutions of Tetramethylam-moniumperfluoroctanesulfonate (TMAFOS) and Diethylammoniumperfluorononanoate (DEAFN) in pure D2O and in mixtures of D2O and H2O. For the TMAFOS-solutions the experimentally observed scattering functions, i.e. the coherent scattering intensity as a function of the scattering angles, could be fitted very well for large scattering angles with the theoretically calculated scattering function for rodlike particles and the dimensions of the rods could be evaluated from these fits. The radius of the rods was independent of the detergent concentration and equal to the double length of a detergent molecule. For small scattering angles the scattering function showed a maximum which was due to nearest neighbour order between the aggregates resulting from the intermicellar interaction. From this maximum a mean distance between the aggregates and hence the lengths L of the rods could be calculated. For the DEAFN-solutions the observed scattering function showed no maximum what clearly indicates the absence of nearest neighbour order between the aggregates. The experimentally observed scattering functions could not be fitted on the basis of rodlike aggregates, but agreed rather well with the theoretically calculated scattering functions for disclike aggregates and also for vesicle-like double layers. The dimensions for the discs could be evaluated from the fits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01448149
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Trajectories of para- and freeomagnetic particles in HGMS filters with axial configurations (1981)
    Springer
    Applied physics 24 (1981), S. 229-232 
    Details
    ISSN: 1432-0630
    Keywords: 51 ; 84
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The trajectories of para-and ferromagnetic particles with velocities between 0.04 and 2.5 cm s−1 have been investigated in an HGMS model system with axial configuration. A single-wire system has been observed by a TV system. The trajectories were compared with the ideal (inviscid flow) and laminar (viscous flow) model. The results agree with laminar flow model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00899762
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Differential evaluation of the Hall effect in silicon with oxygen-related donors (1984)
    Springer
    Applied physics 33 (1984), S. 47-50 
    Details
    ISSN: 1432-0630
    Keywords: 71.55.Fr ; 72.80.Cw
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The free-electron concentration as a function of the temperature is analyzed differentially for silicon with oxygen-related donors formed by annealing at 430 °C. The analysis yields defect levels atE c−0.25 eV,E c−0.14eV, andE c−0.055 eV assuming the degeneracy factors to be unity. The corresponding defect level concentrations are approximately proportional to the annealing time. Their formation rates are between 1 and 3×1010cm−3s−1 at 430 °C annealing temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01197085
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Critical capture radius in single wire HGMS (1981)
    Springer
    Applied physics 24 (1981), S. 225-228 
    Details
    ISSN: 1432-0630
    Keywords: 51 ; 84
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The observation of a large number of particle trajectories in a transversi single wire HGMS has made possible the experimental determination of the critical capture radius. Both the trajectories and the capture radius were found to be in good agreement with calculated values obtained by numerical means using a laminar flow model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00899761
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Charge carrier statistics of semiconductors containing defects with negative electronic correlation energy (1982)
    Springer
    Applied physics 27 (1982), S. 39-47 
    Details
    ISSN: 1432-0630
    Keywords: 71.55.Fr ; 72.80.Cw ; 71.45.Gm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The free charge carrier concentration as a function of the reciprocal temperature and the doping level [p(1/T)- andp(C)-characteristics] is calculated from the neutrality equation of a semiconductor containing positive or negativeU centers. The typical exponential laws and power laws of thep(1/T)- andp(C)-characteristics are given both for positive and negative correlation energy of the bound charge carrier pairs. Furthermore, the characteristics are evaluated differentially, in order to obtain criteria for the presence of negativeU centers in semiconductors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01197545
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Small angle neutron scattering measurements on micellar solutions of perfluor detergents (1983)
    Springer
    Colloid & polymer science 261 (1983), S. 1043-1049 
    Details
    ISSN: 1435-1536
    Keywords: Detergents ; micelles ; vesicles ; neutron scattering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Small angle neutron scattering experiments (SANS) were carried out with solutions of the Lithium salt of Perfluoroctanoic acid (LIPFO) in pure D2O and mixtures of D2O and H2O and Diethylammoniumperfluorononanoate (DEAFN). For LIPFO the scattering intensity as a function of the scattering angles could be fitted with calculated scattering functions for spheres. The contrast variation method allowed us to extract accurate values for the radius, the concentrations of the micelles and the aggregation number. For DEAFN the observed scattering function could be fitted on the basis of spherical vesicles with an appreciable variance in diameter. For several solutions these parameters and the concentration of the vesicles could be evaluated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01421713
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Synthesis of 2-Norzizaene and 9,10-Dehydro-2-norzizaene (7,7-Dimethyl-6-methylidenetricyclo[6.2.1.01,5]undec-9-ene) via Intramolecular Allyl Cation Induced CycloadditionPreliminary account: [1]. (1983)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 66 (1983), S. 828-841 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 7,7-Dimethyl-6-methylidenetricyclo[6.2.1.01,5]undec-9-ene (10) has been prepared from allylic alcohol 8 in one step in 16% yield. Selective hydrogenation of 10 with diazene gives the 2-norzizaenes 1a and 11.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19830660316
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Strained Ketenes from α-Bromoacyl Phosphates. (Tricyclo[4.4.1.01,6]undeca-3,8-dien-11-ylidene)methanone and its Heptacyclic Dimer: a Dispirobridged Dipropellane (1,1″,4,4″,5,5″,8,8″-Octahydrodispiro[[4a, 8a]methanonaphthalene-9,1′-cyClobutane-3′,9″-[4a, 8a]methanonaphthalene]-2′, 4′-dione) (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1930-1936 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dehalogenation of the mixed anhydride 6 of 11-bromotricyclo[4.4.1.01,6] undeca-3,8-diene-11-carboxylic acid (4) and of diethyl hydrogen phosphate with Zn-Ag couple in THF gave the dispiro-fused dipropellane 8(1,1″,4,4″,5,5″,8,8″-octahydrodispiro[[4a, 8a]methanonaphthalene-9,1′-cyclobutane-3′,9″-[4a, 8a]methanonaphthalene]-2′,4′-dione) in 58% yield. Unlike other dispiro[2.1.2.1]octane-4, 8-diones (see 2a-e), the new cyclodimer 8 is an O2-sensitive compound. The 11-bromobicyclo[4.4.1] undeca-1,3,5,7,9-pentaene-11-carboxylic acid (13) was prepared and converted into the acyl phosphate 14, which in turn was reduced with Zn-Ag couple in THF/MeOD to give the deuterated ester 16. Other cyclopropylidenemethanones could be generated and dimerized advantageously by the Zn-induced reduction of the mixed anhydride of the 1-bromocyclopropanecarboxylic acid and diethyl hydrogen phosphonate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710812
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    1,4-Diazobicyclo[2.2.2]octane-catalyzed coupling of aldehydes and activated double bondsPart 2: see [1].. Part 3. A short ans practical synthesis of mikanecic acid (4-vinyl-1-cyclohexene-1,4-dicarboxylic acid) (1984)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 413-415 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title dicarboxylic acid 1d has been prepared in 24% overall yield via, 1,4-diazabicyclo[2.2.2]octane (DABCO)-catalyzed coupling of ethanal and tert-butyl propenoate (3) to 4, SN2′-reaction to tert-butyl (Z)-2-romomethyl-2-butenoate (5a), dehydrobrominatin to tert-butyl 2-methylidene-3-butenoate (2c), dimerizatoin to di-tert-butyl 4-vinyl-1-cyclohexene-1,4-dicarboxylate (1c) and acidic ester cleavage. Acidic cleavage of easily obtainable 5a affords (Z)-2-bromomethyl-2-butenoic acid (5a) in 68% yield with respect to ethanal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19840670209
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    α-Methylidene- and α-Alkylidene-β-lactams from Nonproteinogenic Amino Acids (1991)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 74 (1991), S. 1213-1220 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of methyl 2-(1-hydroxyalkyl)prop-2-enoates 1 with conc. HBr solution afforded methyl (Z)-2-(bromomethyl)alk-2-enoates 2, which were transformed regioselectively into N-substituted methyl (E)-2- (aminomethyl)alk-2-enoates 3 (SN2 reaction) and into N-substituted methyl 2-(1-aminoalkyl)prop-2-enoates 4(SN2′ reaction). Regiocontrol of nucleophilic attack by amine was accomplished simply by choice of solvent, the SN2 reaction occurring in MeCN and the SN2′ reaction in petroleum ether. Hydrolysis and lactamization afforded β-lactams 7 and 8, containing an exocyciic alkylidene and methylidene group at C(3), respectively.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19910740608
    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...