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81.
In many fields of engineering thin porous components are used, e.g. as damping elements for noise insulation in cars or walls in buildings. Today these elements are often calculated using a numerical 3-D model. Because of numerical problems which occur using a 3-D model for thin transversly loaded structures a plate theory is advantageous. To take into account the porous structure as well as the damping effect of the porosity of these components a poroelastic plate theory is necessary. Several posibilities exist to establish plate theories. Generally, methods to derive a plate theory require a priory assumptions motivated by engineering intuition (like the classical Kirchhoff normal hypothesis). In this contribution a priori assumptions are not used. Plate theories of different orders are derived from the 3-D poroelastic theory using series expansion. For elastic plates this idea was introduced in [3]. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
82.
Christian Schwinger Albrecht Klemenz Karsten Busse Jörg Kressler 《Macromolecular Symposia》2004,210(1):493-499
Microencapsulation of cells producing recombinant proteins or hormones leads to immunoprotection and immobilization in culture or in vivo. We are investigating three different strategies for the production of calcium cross-linked alginate beads of a small size with immobilized and immunoprotected mammalian cells: a) the AirJet technology (coaxial gas flow extrusion), b) the vibrating nozzle technology, and c) the JetCutter technology. A alginate/poly-L-lysine/alginate complexation was used as the polymeric system. All three methods may be used for production of homogeneous beads with a diameter of approximately 350 μm. While the vibrating nozzle technique was limited to an alginate viscosity of 0.2 Pa·s or less, the AirJet and JetCutter technology were less sensitive to higher viscosities. High frequency Scanning Acoustic Microscopy is used for mechanical characterization of the microspheres as well as for investigation of surface properties. 相似文献
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Both 6-year-old children and adults showed as good performance on a syllable identification task for a test condition having more trials per test run and a lower overall level of positive reinforcement as they did for a condition with fewer trials per test run and a higher, overall level of positive reinforcement. Differences between identification thresholds of children and adults are interpreted as reflecting age-related differences in speech processing rather than differences in responding to the test situation. 相似文献
87.
Aitala EM Amato S Anjos JC Appel JA Ashery D Banerjee S Bediaga I Blaylock G Bracker SB Burchat PR Burnstein RA Carter T Carvalho HS Copty NK Costa I Cremaldi LM Darling C Denisenko K Fernandez A Gagnon P Gerzon S Gobel C Gounder K Halling AM Herrera G Hurvits G James C Kasper PA Kwan S Langs DC Leslie J Lundberg B MayTal-Beck S Meadows B de Mello Neto JR Milburn RH de Miranda JM Napier A Nguyen A d'Oliveira AB O'Shaughnessy K Peng KC Perera LP Purohit MV Quinn B Radeztsky S Rafatian A 《Physical review letters》1996,77(12):2384-2387
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E.B. Bradley R.H. Herber P.J. Busse K. Niedenzu 《Journal of organometallic chemistry》1973,52(2):297-306
The vibrational spectra of 1,3-dimethyl-2-(trimethylstannyl)-1,3-diaza-2-boracyclopentane and the corresponding diazacyclohexane derivatives as well as those of some other 1,3-diaza-2-boracycloalkanes have been recorded. Boron-nitrogen valence vibrations are observed in the 1500±10 cm?1 frequency region and boron-tin stretching is assigned near 760 cm?1. These data are discussed in conjunction with the 11B and 1H NMR spectra of the various heterocycles and the tin Mössbauer spectra of the two boron-tin species. 相似文献
90.
Sida Wang Phil Liebing Felix Engelhardt Liane Hilfert Sabine Busse Rüdiger Goldhahn Frank T. Edelmann 《无机化学与普通化学杂志》2023,649(1):e202200289
The current library of amidinate ligands has been extended by the synthesis of two novel dimethylamino-substituted alkynylamidinate anions of the composition [Me2N−CH2−C≡C−C(NR)2]− (R = iPr, cyclohexyl (Cy)). The unsolvated lithium derivatives Li[Me2N−CH2−C≡C−C(NR)2] ( 1 : R = iPr, 2 : R = Cy) were obtained in good yields by treatment of in situ-prepared Me2N−CH2−C≡C−Li with the respective carbodiimides, R−N=C=N−R. Recrystallization of 1 and 2 from THF afforded the crystalline THF adducts Li[Me2N−CH2−C≡C−C(NR)2] ⋅ nTHF ( 1 a : R = iPr, n=1; 2 a : R = Cy, n=1.5). Precursor 2 was subsequently used to study initial complexation reactions with selected di- and trivalent transition metals. The dark red homoleptic vanadium(III) tris(alkynylamidinate) complex V[Me2N−CH2−C≡C−C(NCy)2]3 ( 3 ) was prepared by reaction of VCl3(THF)3 with 3 equiv. of 2 (75 % yield). A salt-metathesis reaction of 2 with anhydrous FeCl2 in a molar ratio of 2 : 1 afforded the dinuclear homoleptic iron(II) alkynylamidinate complex Fe2[Me2N−CH2−C≡C−C(NCy)2]4 ( 4 ) in 69 % isolated yield. Similarly, treatment of Mo2(OAc)4 with 3 or 4 equiv. of 2 provided the dinuclear, heteroleptic molybdenum(II) amidinate complex Mo2(OAc)[Me2N−CH2−C≡C−C(NCy)2]3 ( 5 ; yellow crystals, 50 % isolated yield). The cyclohexyl-substituted title compounds 2 a , 4 , and 5 were structurally characterized through single-crystal X-ray diffraction studies. 相似文献