280 research outputs found
Thermal analysis aids sintering of hardmetals
No full textS.32-37Thermal analysis is a valuable route not only for improving our understanding of the basic mechanisms operating in the sintering of hardmetals, but also for optimizing the production of these materials. Gert Leitner, Klaus Jaenicke-Roessler, Tim Gestrich and Torsten Breuning of the Fraunhofer-Institut fuer Keramische und Sinterwerkstoffer in Dresden, Germany, have used these tools to investigate the dewaxing, outgassing and sintering of both normal-grained and fine-grained hardmetals.52Nr.1
Time resolution of TileCal and searches for heavy metastable particles
No full textTitle: Time resolution of TileCal and searches for heavy metastable parti- cles Author: Martina Pagáčová Department: Institute of Particle and Nuclear Physics Supervisor: Doc. RNDr. Rupert Leitner, DrSc. Supervisor's e-mail address: [email protected] Abstract: In the present work, the timing of the ATLAS TileCal is stud- ied using the single hadron collision data. The time resolution and also the mean time response depend on the energy deposited in a given cell. The results are compared to the previous analysis with jets and muons. Precise time-of-flight measurement using TileCal can be used to identify the heavy long-lived particles predicted by the models of physics beyond the standard model. Their mass can be reconstructed by combining with the momentum measurement in the ATLAS inner detector. Finally, the mass resolution of an exotic particle with mass M = 600 GeV is estimated. Keywords: ATLAS experiment, TileCal, time resolution, stable massive particle
Časové rozlišení TileCalu a hledání těžkých dlouhožijících částic
No full textNázev práce: Časové rozlíšenie TileCalu a hl'adanie t'ažkých metastabilných častíc Autor: Martina Pagáčová Ústav: Ústav částicové a jaderné fyziky Vedoucí diplomové práce: doc. RNDr. Rupert Leitner, DrSc. E-mail vedoucího: [email protected] Abstrakt: Predložená práca sa zaoberá štúdiom časovania kalorimetru Tile- Cal experimentu ATLAS prostredníctvom dát single hadrónov. Časové rozlíšenie rovnako ako odozva stredného času závisia na deponovanej energii v danej cele. Výsledky sú porovnané s predchádzajúcimi analýzami s jetmi a miónami. Presné meranie doby letu pomocou TileCalu môže identifikovat' t'ažké dlhožijúce častice, ktoré sú predpovedané modelmi za štandardným modelom. Ich hmotu je možné zrekonštruovat' skombinovaním tohto merania s meraním hybnosti vo vnútornom detektore experimentu ATLAS. Nakoniec je vypočítaná chyba určenia hmoty exotickej častice o hmotnosti M = 600 GeV. Klíčová slova: ATLAS experiment, TileCal kalorimeter, časové rozlíšenie, stabilné t'ažké časticeTitle: Time resolution of TileCal and searches for heavy metastable parti- cles Author: Martina Pagáčová Department: Institute of Particle and Nuclear Physics Supervisor: Doc. RNDr. Rupert Leitner, DrSc. Supervisor's e-mail address: [email protected] Abstract: In the present work, the timing of the ATLAS TileCal is stud- ied using the single hadron collision data. The time resolution and also the mean time response depend on the energy deposited in a given cell. The results are compared to the previous analysis with jets and muons. Precise time-of-flight measurement using TileCal can be used to identify the heavy long-lived particles predicted by the models of physics beyond the standard model. Their mass can be reconstructed by combining with the momentum measurement in the ATLAS inner detector. Finally, the mass resolution of an exotic particle with mass M = 600 GeV is estimated. Keywords: ATLAS experiment, TileCal, time resolution, stable massive particlesÚstav částicové a jaderné fyzikyInstitute of Particle and Nuclear PhysicsMatematicko-fyzikální fakultaFaculty of Mathematics and Physic
Coordination properties of a 2-(diphenylphosphino)guanidine ligand
No full textTitle: Coordination properties of phosphinoguanidine ligand Author: Bc. Zdeněk Leitner Institution: Faculty of Science, Charles University in Prague, Department of Inorfanic Chemistry Supervisor: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Polar phosphine ligands have found use in variety of homogenous and biphasic catalytic processes. In the past, extensive research has been performed also on cationic phosphines, namely phosphinoguanidinium salts. However, neutral phosphinoguanidines have been mostly neglected and their coordination chemistry has not been described to a satisfactory extent, even though the combination of soft phosphorous and harder nitrogen Lewis base could exhibit interesting properties, mainly hemilabile coordination, as well as protonation-controlled nitrogen coordination. These properties could have a positive impact on catalytical performance of this ligand in systems, which benefit from hydrogen bonding or the presence of basic guanidine group. The aim of this work was to study coordination properties of an earlier prepared ligand L and the corresponding phosphinoguanidine salt L·HCl in reactions with Group 11 metal precursors. New compounds were characterized, and their crystal structures were determined. In addition to conventional compounds, an uncommon dimeric complex...Shrnutí Název práce: Koordinační vlastnosti fosfinoguanidinového ligandu Autor: Bc. Zdeněk Leitner Instituce: Přírodovědecká fakulta Univerzity Karlovy v Praze, Katedra anorganické chemie Vedoucí práce: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Polární aniontové fosfinové ligandy nalezly uplatnění v široké škále homogenních i bifázových katalytických procesů. V minulosti tak byl proveden rozsáhlý výzkum i na poli kationtových fosfinových ligandů, konkrétně fosfinoguanidiniových solí. Od nich odvozené neutrální fosfinoguanidiny byly však dosud převážně opomíjeny a zejména jejich koordinační chování nebylo dosud uspokojivě prozkoumáno. Přitom kombinace měkkého fosfinového a tvrdšího dusíkatého donoru může přinášet zajímavé vlastnosti z hlediska hemilabilní koordinace, či protonací řiditelné koordinace guanidinové funkční skupiny. Tyto vlastnosti mohou mít pozitivní vliv na průběh katalytických dějů, v nichž se uplatňuje tvorba vodíkových můstků, nebo přítomnost bazické funkční skupiny. Obsahem této práce je studie koordinačních vlastností dříve připraveného fosfinoguanidinového ligandu L a od něj odvozené fosfinoguanidiniové soli L·HCl v reakcích s prekurzory kovů 11. přechodné skupiny. Připravené koordinační sloučeniny byly charakterizovány a byla určena jejich krystalová struktura metodou difrakce...Department of Inorganic ChemistryKatedra anorganické chemiePřírodovědecká fakultaFaculty of Scienc
Coordination properties of a 2-(diphenylphosphino)guanidine ligand
No full textShrnutí Název práce: Koordinační vlastnosti fosfinoguanidinového ligandu Autor: Bc. Zdeněk Leitner Instituce: Přírodovědecká fakulta Univerzity Karlovy v Praze, Katedra anorganické chemie Vedoucí práce: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Polární aniontové fosfinové ligandy nalezly uplatnění v široké škále homogenních i bifázových katalytických procesů. V minulosti tak byl proveden rozsáhlý výzkum i na poli kationtových fosfinových ligandů, konkrétně fosfinoguanidiniových solí. Od nich odvozené neutrální fosfinoguanidiny byly však dosud převážně opomíjeny a zejména jejich koordinační chování nebylo dosud uspokojivě prozkoumáno. Přitom kombinace měkkého fosfinového a tvrdšího dusíkatého donoru může přinášet zajímavé vlastnosti z hlediska hemilabilní koordinace, či protonací řiditelné koordinace guanidinové funkční skupiny. Tyto vlastnosti mohou mít pozitivní vliv na průběh katalytických dějů, v nichž se uplatňuje tvorba vodíkových můstků, nebo přítomnost bazické funkční skupiny. Obsahem této práce je studie koordinačních vlastností dříve připraveného fosfinoguanidinového ligandu L a od něj odvozené fosfinoguanidiniové soli L·HCl v reakcích s prekurzory kovů 11. přechodné skupiny. Připravené koordinační sloučeniny byly charakterizovány a byla určena jejich krystalová struktura metodou difrakce...Title: Coordination properties of phosphinoguanidine ligand Author: Bc. Zdeněk Leitner Institution: Faculty of Science, Charles University in Prague, Department of Inorfanic Chemistry Supervisor: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Polar phosphine ligands have found use in variety of homogenous and biphasic catalytic processes. In the past, extensive research has been performed also on cationic phosphines, namely phosphinoguanidinium salts. However, neutral phosphinoguanidines have been mostly neglected and their coordination chemistry has not been described to a satisfactory extent, even though the combination of soft phosphorous and harder nitrogen Lewis base could exhibit interesting properties, mainly hemilabile coordination, as well as protonation-controlled nitrogen coordination. These properties could have a positive impact on catalytical performance of this ligand in systems, which benefit from hydrogen bonding or the presence of basic guanidine group. The aim of this work was to study coordination properties of an earlier prepared ligand L and the corresponding phosphinoguanidine salt L·HCl in reactions with Group 11 metal precursors. New compounds were characterized, and their crystal structures were determined. In addition to conventional compounds, an uncommon dimeric complex...Department of Inorganic ChemistryKatedra anorganické chemiePřírodovědecká fakultaFaculty of Scienc
Exploring Emptiness: An Investigation of MA and MU in My Sonic Composition Practice
No full textThe commentary investigates Japanese aesthetics of space, silence and emptiness - ma and mu - that informed my compositional practice during the research period 2012 - 2015. The portfolio comprises text compositions and sound installations in which forms of micro events and sustained events are employed. Throughout, the emphasis is on my personal engagement with, and manifestation of emptiness that concerns a particular model of listening and perception.
Chapter 1 discusses six primary research areas: ma and mu, material, text, form, listening and perception. Firstly, I introduce ma and mu by examining noh culture and Zeami's teaching of senu hima (where there is no-action) in the context of my personal approaches to music. The following subjects are then used to contextualise my PhD practice by means of examples from various composers and visual artists. Here, these particular and enigmatic concepts are explored through Japanese art as well as Western contemporary works by Alvin Lucier, Eliane Radigue and those of the Wandelweiser collective.
Part 2 provides contextual commentaries on selected compositions from the portfolio that mostly articulate my aesthetics in relation to the topics covered in Chapter 1. koso koso addresses my methodologies to investigate the essence of senu hima, followed by treow that discusses my approach to materials and the importance of space. I move on to grade two and grade two extended in order to examine text scores, and then, look into Espèces d'espaces 03 and 04 as examples of musical forms that I employ.
Finally, listening and perception are investigated through the compositions gnome and con.de.structuring. Throughout, I describe how my works explore emptiness as a result of my particular emphasis on listening over composing
Coordination properties of a 2-(diphenylphosphino)guanidine ligand
No full textTitle: Coordination properties of phosphinoguanidine ligand Author: Bc. Zdeněk Leitner Institution: Faculty of Science, Charles University in Prague, Department of Inorfanic Chemistry Supervisor: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Polar phosphine ligands have found use in variety of homogenous and biphasic catalytic processes. In the past, extensive research has been performed also on cationic phosphines, namely phosphinoguanidinium salts. However, neutral phosphinoguanidines have been mostly neglected and their coordination chemistry has not been described to a satisfactory extent, even though the combination of soft phosphorous and harder nitrogen Lewis base could exhibit interesting properties, mainly hemilabile coordination, as well as protonation-controlled nitrogen coordination. These properties could have a positive impact on catalytical performance of this ligand in systems, which benefit from hydrogen bonding or the presence of basic guanidine group. The aim of this work was to study coordination properties of an earlier prepared ligand L and the corresponding phosphinoguanidine salt L·HCl in reactions with Group 11 metal precursors. New compounds were characterized, and their crystal structures were determined. In addition to conventional compounds, an uncommon dimeric complex..
Synthesis and coordination properties of phosphinoguanidine ligands
No full textTitle: Synthesis and coordination properties of phosphinoguanidine ligands Author: Zdeněk Leitner Department: Department of Inorganic chemistry Supervisor: prof. RNDr. Petr Štěpnička, Ph.D. DSc. Abstract: The aim of this work was the preparation and characterisation of a hybrid P,N-donor ligand, 2-(2-(diphenylphosphanyl)phenyl)-1,3-diisopropylguanidine (compound 2), containing a polar guanidine moiety. Potential use of this ligand lies in the preparation of catalytically active complexes with a possible change of distribution between organic and water phase upon altering pH. Firstly, synthesis of the starting materiál, (2-aminophenyl)diphenylphosphine, by copper(I)- catalysed P-C coupling reaction was optimized, up to 88% yield. Preparation of compound 2 was optimized as well. Salt 4 was prepared by protonation of 2. In order to evaluate basicity of phosphine groups in the structure of 2 and 4 and an impact of guanidine moiety protonation, corresponding selenides 3 and 5 were prepared and the 1 JPSe were measured. Ligand 2 was prepared by addition of (2-aminophenyl)diphenylphosphine across 1,3-diisopropylcarbodiimide. Selenide 3 was obtained from eaction of 2 with KSeCN. Salts 4 and 5 were prepared by neutralizing compounds 2 and 3 with hydrochloric acid. All novel compounds were characterized by 1..
Turning urban studies inside/out
No full textProcess and practice have been watchwords for this book, as they were for the collaborative seminar that proceeded it. Along with our collaborators, we have been concerned to excavate and explicate generative modes and models of practice, in both creative research and constructive critique. The monographs that were the focus for Part II of the collection were each encountered, as we indicated in Chapter 3, not simply s ‘finished’ contributions but more as windows onto different forms of research practice. Specifically, they were each rea for methodology and reverse-engineered as a means to uncover the underlying conditions and constitutive practices involved in their production; to find and position both the author and her research practices in the text; and to derive lessons and insights from this process in a manner attuned to the interests and concerns of researchers entering the field. Furthermore, in tracing the path from a collaborative seminar for graduate students to a published collection of essays, reflections, and keyword entries, we have sought in a parallel fashion to be transparent and reflexive about our own (shared) processes and practices
Ultrafast processes in molecules visualized with femtosecond pump probe photoelectron spectroscopy
No full text- …
