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101.
Henrik Schulz 《Discrete Applied Mathematics》2009,157(16):3485-3493
In this paper we introduce an algorithm for the creation of polyhedral approximations for certain kinds of digital objects in a three-dimensional space. The objects are sets of voxels represented as strongly connected subsets of an abstract cell complex. The proposed algorithm generates the convex hull of a given object and modifies the hull afterwards by recursive repetitions of generating convex hulls of subsets of the given voxel set or subsets of the background voxels. The result of this method is a polyhedron which separates object voxels from background voxels. The objects processed by this algorithm and also the background voxel components inside the convex hull of the objects are restricted to have genus 0. The second aim of this paper is to present some practical improvements to the discussed convex hull algorithm to reduce computation time. 相似文献
102.
Per Helvig Christensen Steen Mørup Henrik Topsøe Bjerne Steffen Clausen 《Hyperfine Interactions》1986,28(1-4):945-948
Bimetallic Fe-Co alloy catalysts supported on silica have been studied by use of combined Mössbauer absorption and emisson spectroscopy. Effects of carburization on samples with different particle size are discussed. 相似文献
103.
Harini Kilambi Sirish K. Reddy Lauren Schneidewind Jeffrey W. Stansbury Christopher N. Bowman 《Journal of polymer science. Part A, Polymer chemistry》2009,47(19):4859-4870
The impact of secondary functionalities on the radical‐vinyl chemistry of monoacrylates characterized by secondary functionalities that dramatically enhance their polymerization rate was elucidated utilizing experimental and computational techniques. Firstly, bulk interactions affecting the acrylate reactivity towards photopolymerization were removed by polymerizing at 5 wt % monomer in 1,4‐dioxane. Following deconvolution of bulk interactions impacting reactivity towards photopolymerization, a linear correlation between average polymerization rates and Michael addition reaction rate constants was observed on a logarithmic scale. This result indicates that the presence of the secondary functionality intramolecularly alters the monomer chemistry in a manner which impacts both of these distinct reaction types in a similar manner. These monomers exhibited reduced activation energies in both Michael addition and photopolymerization reactions as compared to hexyl acrylate. Reduction up to 20 ± 8 kJ mole?1was observed for Michael addition reactions and 12 ± 1 kJ mole?1 for photopolymerization reactions, thereby explaining the higher reactivity of the acrylates characterized by the secondary functionalities. Cyclic voltammetry experiments conducted to investigate the nature of the acrylic double bonds indicated that the rapidly polymerizing acrylates are more readily reduced as compared to traditional acrylates. Further, a distinct monotonic correlation of the irreversible cathodic peak potentials of the (meth)acrylates to photopolymerization and Michael addition reactivity was observed. The computationally estimated acrylic LUMO energies characterized by the secondary functionalities (?2.3 eV to ?2.7 eV) were also found to be lower relative to hexyl acrylate (?2.2 eV). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4859–4870, 2009 相似文献
104.
In order to improve the sensitivity of immunometric assays, a chromatographic technique was developed that virtually eliminates components causing non-specific background. Labelled antibodies were applied to a phenyl-Sepharose column in physiological buffer. When labelled anitbodies were purified by this technique, the non-specific background of various time-resolved immunofluorometric assays was reduced 3- to 10-fold and was very close to the instrument background. The assay sensitivity was simultaneously increased by a factor of 2 to 16. This purification method might be used to improve the results of immunometric assays in general. 相似文献
105.
106.
Henrik L. Selberg 《Commentarii Mathematici Helvetici》1934,7(1):171-177
Ohne Zusammenfassung 相似文献
107.
The electronic structure and the electron dynamics of the clean InAs(1 1 1)A 2 × 2 and the InAs(1 1 1)B 1 × 1 surfaces have been studied by laser pump-and-probe photoemission spectroscopy. Normally unpopulated electron states above the valence band maximum (VBM) are filled on the InAs(1 1 1)A surface due to the conduction band pinning above the Fermi level (EF). Accompanied by the downward band banding alignment, a charge accumulation layer is confined to the surface region creating a two dimensional electron gas (2DEG). The decay of the photoexcited carriers above the conduction band minimum (CBM) is originated by bulk states affected by the presence of the surface. No occupied states were found on the InAs(1 1 1)B 1 × 1 surface. This fact is suggested to be due to the surface stabilisation by the charge removal from the surface into the bulk. The weak photoemission intensity above the VBM on the (1 1 1)B surface is attributed to electron states trapped by surface defects. The fast decay of the photoexcited electron states on the (1 1 1)A and the (1 1 1)B surfaces was found to be τ1 1 1 A ? 5 ps and τ1 1 1 B ? 4 ps, respectively. We suggest the diffusion of the hot electrons into the bulk is the decay mechanism. 相似文献
108.
Ohne Zusammenfassung 相似文献
109.
Henrik Ramsay 《欧洲无机化学杂志》1909,42(1):1137-1140
110.
Management review of the quality-management system is an item in many quality standards and a requirement of the ISO 9001:2000
standard and of laboratory standards ISO 15189 and ISO 17125, and others. These reviews are conducted to ensure that the top
management is informed and involved in the quality-management system with respect to continuing adequacy and effectiveness,
and opportunities for improvement of the system. The management review is a process that should be conducted and audited utilizing
the process approach. A process approach is defined as “An activity using resources and managed in order to enable the transformation
of inputs into outputs” (ISO 9001:2000). All identified main processes in the quality system should be monitored through data
collection by appropriate methods, assuring that data are valid, representative, and adequate. For management review data
must be collected and presented in an accessible form so that processes can be evaluated according to objectives, goals, resources,
etc. On the basis of this information the laboratory management makes the necessary decisions and ensure that actions are
taken that improve the effectiveness of the quality-management system. As output from the management review process, there
should be evidence of decisions regarding: change of quality policy and objectives; plans and possible actions for improvements;
corrective actions as appropriate; increased customer satisfaction; and planning of resources needs. Identification of the
processes involved and using the process approach in the management review ensures the continual improvement of the quality
system.
Presented at the conference Quality in the Spotlight, March 2006, Antwerp, Belgium. 相似文献