Search results for "PROPERTY"
showing 10 items of 955 documents
Specific Mechanical Properties of Glass/Carbon Epoxy Composites for Marine Applications
2009
Structure and dielectric breakdown strength of nano calcium carbonate/polypropylene composites
2013
Nanodielectrics, a 21st-century phenomena, is envisioned to be the answer for material challenges in progressive high-voltage technology. It is well known that the proper dispersion of nanoparticles plays a key role in improving the dielectric properties of a material, but to understand where changes in the properties of a material originate, it is also essential to reveal the multiscale structure of the material. In this study, the dielectric permittivity, breakdown strength, and structure of nano calcium carbonate (nano-CaCO3)/polypropylene composites with 1.8-8.1 wt % doping were characterized systematically. The combined results from transmission electron microscopy, Raman microscopy, a…
On the mechanism of radiation synthesis of nanogels
2016
Radiation-engineered poly(N-vinyl pyrrolidone) nanogels are very interesting biocompatible nanocarriers for i.v. administration of therapeutics and contrast agents for bioimaging among other applications. Nanogels are usually produced upon irradiation of dilute aqueous polymer solutions. Under these conditions, the polymer radicals formed primarily react via intramolecular radical-radical combination forming intramolecular crosslinks. The manufacturing process is fast and effective and grants excellent control of particle size and simultaneous sterilization of the formed nanogels. Interestingly, primary amino groups and carboxyl groups, useful for (bio)conjugation, are also formed in a dose…
Representing compact sets of compact operators and of compact range vector measures
1987
Liftings and extensions of operators in Brownian setting
2020
We investigate the operators T on a Hilbert space H which have 2-isometric liftings S with the property S ∗ S H ⊂ H . We show that such liftings are closely related to some extensions of T, which h...
Polaroid-Type Operators
2018
In this chapter we introduce the classes of polaroid-type operators, i.e., those operators T ∈ L(X) for which the isolated points of the spectrum σ(T) are poles of the resolvent, or the isolated points of the approximate point spectrum σap(T) are left poles of the resolvent. We also consider the class of all hereditarily polaroid operators, i.e., those operators T ∈ L(X) for which all the restrictions to closed invariant subspaces are polaroid. The class of polaroid operators, as well as the class of hereditarily polaroid operators, is very large. We shall see that every generalized scalar operator is hereditarily polaroid, and this implies that many classes of operators acting on Hilbert s…
Commutative Partial O*-Algebras
2002
This chapter is devoted to the integrability of commutative partial O*-algebras. Three notions of weak commutativity, commutativity and strong commutativity of an O*-vector space are defined and investigated. In Section 3.1, we analyze the relation between the integrability of weakly commutative O*-vector space M and the commutativity of the von Neumann algebra (M w ′ )′. In Section 3.2, we study the integrable extensions of partial O*-algebras. In Section 3.3, we describe another explicit example, namely, the partial O*-algebra M[S, T] generated by two weakly commuting symmetric operators S and T defined on a common dense domain in a Hilbert space. In particular, we investigate in detail t…
Design principles for collaboration platforms for open education
2015
Increasing the current low uptake of Open Education Resources (OER) is a key challenge for researchers and practitioners in the field. User studies have shown that collaboration is a main success factor for successful open educational activities. However, effective collaboration in open educational contexts requires well planned processes and platforms supporting collaboration, in particular in physically distributed settings. We have been investigating the value of such platforms, their main features and user requirements to enable collaboration from immature ideas to completed resources. We used quantitative and qualitative research methods to collect insights from potential users of such…
Biased graph walks for RDF graph embeddings
2017
Knowledge Graphs have been recognized as a valuable source for background information in many data mining, information retrieval, natural language processing, and knowledge extraction tasks. However, obtaining a suitable feature vector representation from RDF graphs is a challenging task. In this paper, we extend the RDF2Vec approach, which leverages language modeling techniques for unsupervised feature extraction from sequences of entities. We generate sequences by exploiting local information from graph substructures, harvested by graph walks, and learn latent numerical representations of entities in RDF graphs. We extend the way we compute feature vector representations by comparing twel…