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
Filter
  • Springer  (166)
  • American Association for the Advancement of Science (AAAS)  (4)
  • 1995-1999  (93)
  • 1990-1994  (77)
Collection
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of insect behavior 8 (1994), S. 181-188 
    ISSN: 1572-8889
    Keywords: Belostomatidae ; giant water bugs ; paternal care ; infanticide counterstrategy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The male giant water bug'sLethocerus deyrollei counterstrategy against egg mass destruction by the female was investigated in the laboratory. When mature females encounter a brooding male, they destroy his egg mass and thereby take over the mate and gain a nurse for their own egg mass. However, when the male stays on egg masses laid above the water surface, females cannot detect the male nor the egg mass. Eggs of this species fail to hatch without being supplied with water by males. In the observation, brooding males frequently ascend the stick to the egg mass and stay there for long periods, although most of the water attached to their body surface flowed down in 90 s. These long stays on egg masses are regarded as countestrategies against females.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1572-879X
    Keywords: Surface-bound Rh4−xCox(CO)12 ; THP-grafted silica ; olefin hydroformylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Rh4-xCox(CO)12 (x = 0, 2, 3) are attached by carbonyl substitution to THP (tris-hydroxymethylphospine)-grafted silica keeping their cluster frameworks. They have been characterized by Rh K-edge EXAFS (extended X-ray absorption fine structure) and Fourier transform IR spectroscopy. They exhibited high catalytic activity with 〉 98% selectivity in gas phase hydroformylation of ethene and propene to give aldehydes under mild conditions (40 kPa and 300–373 K).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1572-879X
    Keywords: methane ; dehydrocondensation ; benzene ; ethylene ; Re catalyst ; HZSM‐5
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new family of rhenium‐based catalysts bearing HZSM‐5 zeolite exhibits remarkable performances for the catalytic dehydrocondensation of methane with CO/CO2 towards ethylene, benzene, and naphthalene in high selectivity of above 90% at 1–3 atm and 973–1023 K. In contrast to Mo/HZSM‐5 catalysts, the EXAFS and TG/DTA/Mass studies reveal that the metallic Re on HZSM‐5 zeolite is a catalytically active and stable phase for the reaction.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1572-9028
    Keywords: CO hydrogenation ; EXAFS characterization ; FTIR characterization ; Ru, RuCo and Co carbonyl clusters in NaY and NaX zeolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Some Ru and Co carbonyl clusters in zeolite pores such as Ru3(CO)12/NaY, [HRu6(CO)18]−/NaY, [Ru6(CO)18]2−/NaX, Co4(CO)12/NaY and Co6(CO)16/NaY were prepared by the ship-in-bottle technique, and characterized by FTIR and EXAFS. The RuCo bimetallic carbonyl cluster was prepared by reductive carbonylation of the oxidized RuCo/NaY, which provides the proposed assignment to [HRUCo3(CO)12]/NaY. The tailored Ru, RuCo and Co catalysts were prepared by H2 reduction from the precursors, e.g. Ru, RuCo bimetallic and Co carbonyl clusters impregnated on SiO2 and entrapped in NaY and NaX zeolites. The RuCo bimetallic carbonyl cluster-derived catalysts showed substantially higher activities and selectivities for oxygenates such as C1–C5 alcohols in CO hydrogenation (CO/H2 = 0.33-1.0, 5 bar, 519–543 K). By contrast, hydrocarbons such as methane were preferentially obtained on the catalysts prepared from Ru6, Ru3 and Co4 carbonyl clusters and provided lower CO conversion and poor selectivities for oxygenates. The RuCo bimetals are proposed to be associated with the selective formation of higher alcohols in CO hydrogenation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1572-879X
    Keywords: Supported Mo-promoted Rh-catalysts ; heteronuclear clusters ; olefin hydroformylation ; acetaldehyde hydrogenation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Molybdenum promoted Rh/SiO2 catalysts have been prepared by using the heteronuclear cluster (C5H5)3RhMo2(CO)5 as well as metal salt precursors. The promoting effect of molybdenum has been studied for the hydroformylation of ethene and propene and the hydrogenation of acetaldehyde. It has been found that molybdenum, especially on the cluster-derived catalyst, increases both the hydrogenation and the hydroformylation rate of the olefins. No specific influence on the CO insertion reaction could be obtained. As an explanation, the promotion of the initial step to form intermediate surface alkyl groups has been proposed as the rate determining step for ethene hydroformylation. The promotion of the alcohol formation by bimetallic centers having Rh and Mo in close vicinity has been supported by the results of the hydrogenation of acetaldehyde.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1434-601X
    Keywords: PACS:25.85.-w Fission reactions – 25.85.Ge Charged-particle-induced fission
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: Angular distributions of fission fragments with mass number A=97-159 have been measured by the radiochemical recoil-catcher method in the proton-induced fission of 244Pu with the incident energy of 15 MeV. Angular anisotropies of extreme asymmetric mass division products even up to the fragment mass ratio of A H /A L ∼ 1.85 are found not any different from those of the typical asymmetric mass division products with A∼ 138, which indicates that no clear evidence is observed for the existence of an additional saddle point configuration in the extreme asymmetric mass division. The correlation between the saddle point state evaluated from the angular anisotropy and the mass division mode is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 349 (1994), S. 143-146 
    ISSN: 1434-601X
    Keywords: 23.40.−s ; 23.20.LV ; 27.60.+j
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new isotope,127Pr, has been identified and its decay has been studied using on-line isotope separation of94Mo (36Ar,p2n) reaction products. The half-life of the isotope was determined to be 7.7(6) s, and a γ/X-ray spectrum has been obtained. A partial level scheme is proposed for127Ce on the basis ofγ-singles,β-gatedγ andγγ-coincidence data.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1420-9071
    Keywords: 4,4′-Methylene-bis(2-chloroaniline) ; MBOCA-DNA adduct ; P450 2B5 ; P450 1A1 ; yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract N-Oxidation of 4,4′-methylene-bis(2-chloroaniline) (MBOCA) may lead to formation of DNA adducts. To determine if cytochrome P450s are involved in the formation of MBOCA derived-DNA adducts, yeast strains expressing rodent P450s were exposed to MBOCA, and32P-postlabelling of nucleotides from yeast genomic DNA was done. Chromatographic analysis on PEI cellulose showed that, upon exposure to MBOCA for 1 h, nine DNA adducts were formed in yeast expressing phenobarbital-inducible rabbit P450 2B5. With a 4-h-exposure, all adducts increased in parallel. In cell-free experiments, the incubation of MBOCA with phenobarbital-induced rat microsomal fraction followed by incubation with thymus DNA, led to the formation of more than ten DNA adducts. When yeast expressing 3-methylcholanthrene-inducible rat P450 1A1 was exposed to MBOCA, one major and two minor adducts were formed. No adducts were detected in control yeast. These results show that recombinant rabbit P450 2B5 exhibits a potential activation of MBOCA and that rat P450 1A1 has some effect. The use of yeast expressing recombinant P450s and the technique of32P-postlabelling facilitates a simple search for chemicals with carcinogenic potential.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Integral equations and operator theory 26 (1996), S. 29-45 
    ISSN: 1420-8989
    Keywords: 47B35 ; 93C25 ; 93B36
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract A complete solution is obtained to the suboptimal Nehari extension problem for transfer functions of parabolic systems with Dirichlet boundary control and smooth observations. The solutions are given in terms of the realization (−A, B, C), whereA is a uniformly strongly elliptic operator of order two with smooth coefficients defined on a bounded open domain Ω ofR d ,B=AB D andB D is the Dirichlet map associated with Dirichlet boundary conditions andC is a bounded observation map fromL 2(Ω) to the output spaceY. The approach is to solve an equivalentJ-spectral factorization problem for this particular realization.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1572-879X
    Keywords: Ship-in-Bottle synthesis ; Pt carbonyl clusters ; NaY zeolites ; EXAFS ; 13CO exchange ; NO + CO reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract [Pt9(CO)18]2−/NaY (orange-brown, 2056 and 1798 cm−1), [Pt12(CO)24]2−/NaY (dark-green, 2080 and 1824 cm−1 and [Pt15(CO)30]2−/NaX (yellow-green, 2100 and 1865 cm−1) were stoichiometrically synthesized by the reductive carbonylation of [Pt(NH3)4]2+/NaY, Pt2+/NaY and Pt2+/NaX, respectively. The IR bands characteristic of their linear carbonyls shift to higher frequencies whereas the bridging CO bands to lower frequencies, compared with those on the external zeolites and in solution. In-situ FTIR studies suggested that the subcarbonyl species such as PtO(CO) and “Pt3(CO)3(μ2 −CO)3” are formed as the proposed intermediates towards [Pt12(CO)24]2−/NaY in the reductive carbonylation of Pt2+/NaY.13CO exchange reaction preceded with the different intrazeolite Pt carbonyl species in the following order of activity at 298–343 K: “Pt3(CO)3(μ2 –CO)3”/NaY ≫ PtO(CO)/NaY〉[Pt9(CO)18]2−/NaY 〉[Pt12(CO)24]2−/NaY. Pt-L3-edge EXAFS measurment for these synthesized samples demonstrated that they are consistent with the Pt carbonyl clusters having trigonal prismatic Pt9 and Pt12 frameworks infered to a series of the Chini complexes such as [NEt4]2[Pt3(CO)6] n ( n = 3–5). The intrazeolite Pt9 and Pt12 carbonyl clusters exhibited higher cataytic activity in NO reduction by CO towards N2 and N2O at 473 K, compared with those on the conventional Pt/Al2O3 catalysts. The mechanism of intrazeolite Pt9-Pt15 carbonyl cluster formation are discussed in terms of the intrazeolite basicity and acidity.
    Type of Medium: Electronic Resource
    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...