205 research outputs found
Poly-1,2-azepine and method of producing a film thereof on a substrate
Gas-phase photopolymerisation of phenylazides results in a new type of polymer, a poly-1,2-azepine. This polymer can be provided on a substrate according to a predetermined pattern by exposing it via a mask. After oxidation an electrically conductive polymer is obtained
Poly-1,2-azepine, method of producing a film of such a polymer on a substrate and a substrate provided with such a polymer
Gas-phase photopolymerisation of phenylazides results in a new type of polymer, a poly-1,2-azepine. This polymer can be provided on a substrate according to a predetermined pattern by exposing it via a mask. After oxidation an electrically conductive polymer is obtained
Erratum: (2x1)-(1x1) Phase Transition on Ge(001): Dimer Breakup and Surface Roughening [Phys. Rev. Lett. 91, 116102 (2003)]
Using low energy electron microscopy, we have investigated the (2×1)-(1×1) phase transition occurring above 925 K on Ge(001). Dimer breakup has been identified as the physical origin of this transition. A quantitative description of the dimer concentration during the transition involves configuration entropy of random monomers within the dimer matrix. The dimer formation energy amounts to 1.2±0.3 eV. Dimer breakup promotes reversible surface disorder by step proliferation and irreversible surface roughening above 1130 K
Dynamic crack propagation in brittle materials : analyses based on fracture and damage mechanics
Abdominal packing for surgically uncontrollable hemorrhage in ruptured abdominal aortic aneurysm repair
AbstractEmergency surgery for ruptured abdominal aortic aneurysms is accompanied with massive blood loss and is correlated with high incidences of coagulopathy. Following established results with abdominal packing to control hepatic hemorrhage, we present this technique for uncontrollable hemorrhage in patients with ruptured abdominal aortic aneurysm. The experience with this technique in 46 patients is described. (J Vasc Surg 2001;33:195-6.
Flow patterns behind the free flow front for a Newtonian fluid injected between two infinite parallel plates
A complete analytical treatment of the 2-dimensional problem of the injection of a Newtonian fluid between two parallel plates is presented. Explicit formulas are derived for the shape of the free flow front, the streamlines behind the flow front, the velocity, deformation and rotation (orientation) of material elements in the flow front region, and the associated stresses there. The analysis is based on complex function theory, and in this, the flow region, inclusive the unknown free flow front, is mapped onto the interior of the unit circle. The mapping function that determines the shape of the flow front is found by solving a Hilbert problem. It is analytically found in how far the actual flow front differs from a semi-circular shape, and it is concluded that the semi-circular approximation seems acceptable. Deformations of material line or area elements due to the fountain flow in the flow front region are followed in time; large deformation and reorientations of the material elements are observed. Our results are compared with results in literature obtained by numerical simulations and by experimental work, and on the whole good correspondence is found
Alloying, de-alloying and reentrant alloying in (sub-)monolayer growth of Ag on Pt(111)
An in-situ nanoscopic investigation of the prototypical surface alloying
system Ag/Pt(111) is reported. The morphology and the structure of the
ultrathin Ag-Pt film is studied using Low Energy Electron Microscopy during
growth at about 800 K. An amazingly rich dynamic behaviour is uncovered in
which stress relieve plays a governing role. Initial growth leads to surface
alloying with prolonged and retarded nucleation of ad-islands. Beyond 50%
coverage de-alloying proceeds, joined by partial segregation of Pt towards the
centre of large islands in violent processes. Upon coalescence the irregularly
shaped vacancy clusters are filled by segregating Pt, which then take a compact
shape (black spots). As a result at around 85% coverage the strain of the
initially pseudo-morphological film is almost completely relieved and
Pt-segregation is at its maximum. Further deposition of Ag leads to transient
re-entrant alloying and recovery of the pseudo-morphological layer. The black
spots persist even in/on several layers thick films. Ex-situ atomic force
microscopy data confirm that these are constituted by probably amorphous
Pt(-rich) structures. The (sub-)monolayer films are very much heterogeneous
De semantiek van Aristoteles: waarheid en betekenis in het tijdperk van het darwinisme
The leading argument of this doctoral thesis is that Aristotle’s text [De Interpretatione] is of methodical relevance for present-day philosophical thinking. In the era of science and technology, the status of philosophy has become problematic. The philosophical questions of old have been either debunked as grammatical misconceptions or reformulated and incorporated into modern scientific enquiry.Given this situation, the aim of this doctoral thesis is twofold. It purports to show that the problematic status of philosophy can be traced back to Aristotle’s [De Interpretatione]. In addition, it shows that this text also contains clues to truth of a more fundamental nature that is not restricted to propositional correctness, thereby opening up the possibility of a transformed way of philosophical thinking.Philosophy of Knowledge and Cognitio
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