3,355 research outputs found
Silica‐immobilized cumyl dithiobenzoate as mediating agent in reversible addition fragmentation chain transfer (RAFT) polymerization
No full textReversible addition fragmentation chain transfer (RAFT) polymerizations of styrene and methyl methacrylate were performed in bulk at 60 degrees C, using cumyl dithiobenzoate as the mediating RAFT agent that has been immobilized via the stabilizing Z-group to nanometer-sized fumed silica particles. Increasing molecular weights with monomer conversion and absence of conventional polymerization activity in the interstitial solution phase were observed when the overall concentration of silica particles was carefully balanced with their respective cumyl dithiobenzoate loading. After completion of the polymerization, potentially sulfur-free polymers with controlled molecular weights were obtained, initially via collecting the terminated polymeric material from the interstitial solution phase and, secondly, via cleavage of the surface-confined polymer by a single addition fragmentation chain transfer step, which provides a pathway for recovery of the solid-supported RAFT agent. Copyright (c) 2006 John Wiley & Sons, Ltd
On the mechanism of radical polymerization of methyl methacrylate with dithiobenzoic acid as mediator
No full textDithiobenzoic acid (DTBA) induces controlled polymerization behaviour in methyl methacrylate polymerization at 60 degrees C, accompanied by a pronounced induction period of several hours. DTBA is partially transformed during this induction period into a dithioester with a tertiary ester group moiety, which constitutes an efficient reversible addition-fragmentation chain transfer (RAFT) agent. The transformation reaction is proposed to proceed via a hydrogen abstraction from DTBA by radicals and subsequent termination of the formed phenylcarbonothioylsulfanyl radical with propagating radicals. The proposed reaction scheme was implemented into a computer model, by which the rate coefficient of the hydrogen abstraction from DTBA and of the reinitiation of the intermediate phenylcarbonothioylsulfanyl radical was estimated. The model is in agreement with all of the species observable by electrospray ionization mass spectrometry, with the extent of the experimental induction periods, and with the absolute concentrations of dithioesters that act as efficient RAFT agents during the polymerization. A protocol that uses a cocktail of initiators is introduced, by which the induction period in DTBA-mediated polymerization is effectively eliminated
Philipp Melanchthon
No full textPhilipp Melanchthon (1497–1560) was, with Martin Luther, the most influential reformer of the church during the 16th century. He was also a reformer of university education, especially theological studies, as well as the school system in Germany. He was responsible for a theological curriculum that included Greek, Hebrew, and philosophy. He, as a professor of Greek at the University of Wittenberg since 1518, was the author of the first generally accepted Protestant confession, known as the Confessio Augustana (1530). He also wrote the first Protestant commentaries on Paul’s letter to the Romans (1519), as well as the first Protestant handbook in systematic theology (1521). He was the main negotiator of the Protestant movement during the diets and religious discussions with the Roman Catholic Church. He is known as the ‘teacher of Germany and Europe’ and is respected as the father of the ecumenical movement. Yet, Melanchthon is not known to South Africans and especially Afrikaans-speaking people who, traditionally, have close links with the reformational tradition. There is not yet one single publication on Melanchthon in Afrikaans or by a South African scholar, making this book, therefore, the first by an Afrikaans-speaking scholar on Melanchthon
#Bitcoin : an analysis of the field of a decentralized virtual currency using twitter data
No full textAuthor Philipp AllerstorferAbstract in englischer SpracheMasterarbeit Universität Linz 201
On Philipp Lersch’s Psychology, Reflection No. 2
No full textАвтор статті зазначає, що у 1930–1970 рр. Ф. Лерш був головним представником гуманітарної течії в німецькомовній психології. Наукову класифікацію людських прагнень і стремлінь було
викладено у головній праці Ф. Лерша «Структура особи» (11-те видання 1970 року). Ф. Лерш зумів
об’єднати у своїм творі інформацію із низки наук (біології, психопатології, із різних психологічних
теорій та концепцій).The author of the article notes that in 1930-1970, Philipp Lersch was the main representative of the
humanitarian direction in German psychology. A scientific classification of human aspirations and ambitions
was described in the main work by Philipp Lersch “Building the Person” (11th ed. of 1970). In his work,
Philipp Lersch managed to combine information from a number of sciences (biology, psychopathology, various
psychological theories and concepts)
Deformation Behavior and Damage Modeling of Polypropylene and Polycarbonate
No full textAuthor Philipp Siegfried StelzerKurzfassungen in deutscher und englischer SpracheMasterarbeit Universität Linz 201
Philipp Timischl x Numeró Art
No full textThis article discusses the intersections of gender and class drag in the work of Austrian artist Philipp Timischl. The essay takes the form of a letter of refusal, discussing why the author is simply too busy, then goes on to discuss other performances of industriousness, from Kevin Floyd's proposal that modern masculinity is a labour based performance through to the artist's own gender enhancing or swapping works
Structural identification of doped silicon clusters
No full textIn this chapter we review recent research on the structural identification of isolated doped silicon clusters by combining state-of-the-art experiments and computational modelling using the density functional theory formalism. The
experimental techniques include chemical probe mass spectrometric methods, infrared action spectroscopy, photoelectron spectroscopy, and x-ray absorption
spectroscopy. Coinage metal elements, transition metals with an incomplete d sub-shell, lanthanides, and non-metallic main-group elements are considered as dopant atoms. The growth mechanisms of the doped silicon clusters are described with particular emphasis on the formation of endohedral cages. Specific species that may be considered as building blocks in future nano-structured materials and
devices are highlighted, thereby exploiting their unique structural, electronic, or magnetic properties.edition: 1stsponsorship: We gratefully acknowledge all who contributed to our original papers on the structural identification of doped silicon clusters: Pieterjan Claes, Philipp Gruene, Marko Haertelt, Dan J. Harding, Jonathan T. Lyon, Gerard Meijer, Vu Thi Ngan, Minh Tho Nguyen, Nguyen Minh Tam, Alex Woodham, and Ludger Wöste. The authors are thankful to the Stichting voor Fundamenteel Onderzoek der Materie (FOM) in providing beam time on FELIX and highly appreciate the skillful assistance of the FELIX staff. This work is supported by the Research Foundation-Flanders (FWO), the KU Leuven Research Council (GOA 14/007), and the Deutsche
Forschungsgemeinschaft within FOR 1282 (FI 893/4).status: Publishe
Author Correction: Auto-aggressive CXCR6+ CD8 T cells cause liver immune pathology in NASH
No full textIn this Article, the surname of Tobias Boettler was incorrectly shown as ‘Böttler’, and the surname of author Jan-Philipp Mallm was incorrectly shown as ‘Malm’. The original Article has been corrected online
Philipp Melanchthon: A short introduction
No full textPhilipp Melanchthon was one of the most influential theologians of the Reformation of the 16th century. He was responsible for transforming the secondary and tertiary educational systems in Germany. He was responsible for a new theological curriculum. He wrote the first Protestant ‘systematic theology’ and was the author of the Confessio Augustana. He is called the ‘teacher of Germany and Europe’. In spite of all the praises, most South Africans know very little about this important theologian. In this year of jubilee, it is imperative that a short introduction to his life and work be published – in the hope that he would receive more attention in future from South African scholars
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