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91.
92.
Frank P. Alt Ludwig L. Bhm Hans‐Frieder Enderle Joachim Berthold 《Macromolecular Symposia》2001,163(1):135-144
HDPE specialities having tailored bimodal molecular mass distributions suitable for applications as e.g. pipe or film material are formed in the Hostalen®‐BM low pressure slurry process. A cascade of two STHD (stirred tank heavy diluent) reactors is used to produce at extremely different reaction conditions in each step of the polymerization an in situ polyethylene blend consisting of a low molecular mass homopolymer and a high molecular mass copolymer. This way, a resin having a very broad molecular mass distribution and an inverse comonomer distribution is obtained. High impact strength, stress crack resistance, stiffness, tensile strength, and good processability are combined and materials showing outstanding properties are achieved. 相似文献
93.
The properties of template-directed nucleation are studied in the transition region where full nucleation control is lost and additional nucleation beyond the prepatterned structure is observed. To get deeper insight into the microscopic mechanisms, Monte Carlo simulations were performed. In this context, the previously used continuous algorithm [F. Kalischewski, J. Zhu, and A. Heuer, Phys. Rev. B 77, 155401, (2008)] was replaced by a discrete one to reduce simulation time and to allow more detailed calculations. The applied method is based on the assumption that the molecules on the surface occupy the sites of a simple fcc lattice. It is shown that a careful mapping of the continuous Monte Carlo technique onto the discrete algorithm leads to a good reproduction of the former results by means of the latter method. Furthermore, the new method facilitates the calculation of the spatial distribution of nuclei on the surface. This provides a detailed comparison with experimental data. 相似文献
94.
Noya Loew Ulla Wollenberger Frieder W. Scheller Martin Katterle 《Bioelectrochemistry (Amsterdam, Netherlands)》2009,76(1-2):28
In this contribution the substitution of the central protoporphyrin IX iron complex of horseradish peroxidase by the respective osmium porphyrin complex is described. The direct electrochemical reduction of the Os containing horseradish peroxidase (OsHRP) was achieved at ITO and modified glassy carbon electrodes and in combination with spectroscopy revealed the three redox couples OsIIIHRP/OsIVHRP, OsIVHRP/OsVHRP and OsVHRP/OsVIHRP. The midpoint potentials differ dependent on the electrode material used with E1/2 (OsIII/IV) of − 0.4 V (ITO) and − 0.25 V (GC), E1/2 (OsIV/V) of − 0.16 V (ITO) and + 0.10 V (GC), and E1/2 (OsV/VI)of + 0.18 V (ITO), respectively. Moreover, with immobilised OsHRP the direct electrocatalytic reduction of hydrogen peroxide and tert-butyl hydroperoxide was observed. In comparison to electrodes modified with native HRP the sensitivity of the OsHRP-electrode for tert-butyl hydroperoxide is higher. 相似文献
95.
Vassileva ND van den Ende D Mugele F Mellema J 《Langmuir : the ACS journal of surfaces and colloids》2006,22(11):4959-4967
We consider single two-dimensional aggregates, containing glass particles, placed at a water/air interface. We have investigated the critical shear rate for break-up of aggregates with different sizes in a simple shear flow. All aggregates break-up nearly at the same shear rate (1.8 +/- 0.2 s(-)(1)) independent of their size. The evolution of the aggregate structure before break-up was also investigated. With increasing shear rate, the aggregates adopt a more circular shape, and the particles order in a more dense, hexagonal structure. A simple theoretical model was developed to explain the experimentally observed break-up. In the model, the aggregate is considered as a solid circular disk that will break near its diameter. The capillary and drag force on the two parts of the aggregate were calculated, and from this force balance, the critical shear rate was found. The model shows a weak size dependence of the critical shear rate for the considered aggregates. This is consistent with the experimental observations. 相似文献
96.
[Structure: see text] A series of organoboron quinolates with emission colors ranging from blue to red have been prepared. In comparison to the respective AlQ3 derivatives a distinct blue-shift of the emission is observed. Theoretical calculations serve to provide insight into the nature of the frontier orbitals and the effect of the substituents in the 5-position of the quinolate ligands on the relative HOMO and LUMO energy levels. An efficient new blue emitting material with a pinacolborane substituent has been identified. 相似文献
97.
98.
We have studied the effect of small amounts of added liquid on the dynamic behavior of a granular system consisting of a mixture of glass beads of two different sizes. Segregation of the large beads to the top of the sample is found to depend in a nontrivial way on the liquid content. A transition to viscoplastic behavior occurs at a critical liquid content, which depends upon the bead size. We show that this transition can be interpreted as a condensation due to the hysteretic liquid bridge forces connecting the beads, and we provide the corresponding phase diagram. 相似文献
99.
We give an elementary self-contained proof to Botha’s theorem on the factorization of a singular transformation into idempotent mappings. 相似文献
100.