Search results for "coordination"
showing 10 items of 1282 documents
Pitch tilt rendering for an 8-DOF driving simulator
2015
International audience; Tilt coordination technique is used for reproducing a sustained linear acceleration in driving simulation by tilting the simulator cabin. Thus a part of gravity is interpreted as a horizontal acceleration. Between the slow rotational motion limited by the rotational perception threshold of semi-circular canals of vestibular system and the fast change of acceleration to render, the design of coupling motions of rotation and translation plays a critical role in the realism of driving simulator. We present here an experiment focusing on longitudinal accelerations rendering with pitch tilt coordination technique. Eight drivers experienced the same accelerations and decel…
Effect of tempo and vision on interpersonal coordination of timing in dyadic performance
2015
Interpersonal coordination within a dyadic musical performance requires that the two musicians share a similar mental model of the music’s timing structure. In addition to non-fluctuating inter-onset-interval, matched mental models can be observed through corporeal articulations and apparent embodiment of musical features (i.e. synchronous body sway, mimicked or complementary gestures). Our aim was to examine the effect of tempo on interpersonal coordination within a musical dyad. Violin dyads performed three unfamiliar collaborative musical sequences in facing vs. non-facing conditions. Our hypotheses were that interpersonal coordination would be weakened in the non-facing conditions, and …
Katalizatory i proces koordynacyjnej polimeryzacji etylenu - eksperyment i teoria
2004
Badania eksperymentalne i teoretyczne koordynacyjnej polimeryzacji etylenu przeprowadzono wobec katalizatorów otrzymanych z prekursorów - kompleksów halogenków Ti, Zr, Hf, V z organicznymi zasadami Lewisa, nośnika magnezowego [MgCl2(THF)2] i związków glinoorganicznych. Określono zależnosć pomiędzy rodzajem halogenków w prekursorze a aktywnością katalizatora wanadowego. Ustalono profile energetyczne reakcji insercji i terminacji (beta-eliminacji) oraz przeniesienia atomu wodoru beta. Obliczone wartości barier insercji, a także energii wiązania etylenu do centrum aktywnego dobrze korelują z wynikami polimeryzacji. Stwierdzono występowanie w centrach aktywnych oddziaływań agostycznych, które o…
Deliberate Play and Preparation Jointly Benefit Motor and Cognitive Development: Mediated and Moderated Effects
2016
In light of the interrelation between motor and cognitive development and the predictive value of the former for the latter, the secular decline observed in motor coordination ability as early as preschool urges identification of interventions that may jointly impact motor and cognitive efficiency. The aim of this study was twofold. It (1) explored the outcomes of enriched physical education, centered on deliberate play and cognitively challenging variability of practice, on motor coordination and cognitive processing; (2) examined whether motor coordination outcomes mediate intervention effects on children’s cognition, while controlling for moderation by lifestyle factors as outdoor play h…
Oxidovanadium(v) complexes with l-proline-based amino acid phenolates
2019
Abstract l -proline was used to prepare chiral, tridentate amino acid phenol proligands H2L1–4. These proligands react with vanadium precursors VO(acac)2, VOSO4∙5H2O and VO(OPr)3 in methanol to form the corresponding oxidoalkoxidovanadium( v ) complexes 1–4. The complexes crystallize from methanol, and are octahedrally coordinated with a general formula [VO(L1–4)(OMe)(MeOH)]. In solution, however, they adopt several different conformations or isomeric structures depending on the solvent.
Structure of calcium and zinc pectinate films investigated by FTIR spectroscopy
2010
International audience; Calcium and zinc pectinate gels were prepared using a method which allowed calcium or zinc to diffuse from the cross-linking solution through a dialysis membrane to form a gel with amidated low-methoxyl pectin. The gel thus obtained was then dried, and the film structure was studied using FTIR spectroscopy as a function of the cation content (0%, 5%, 10%, and 15% w/v). Important consideration was given to the three functional groups (amide, carboxyl ester, and carboxylate groups) present in the pectin. When the zinc content was increased, the three wavenumber values corresponding to these three functional groups did not change significantly, while for calcium pectina…
Multivalent N-donor ligands for the construction of coordination polymers and coordination polymer gels
2018
This work describes the synthesis and characterisation of several multivalent N-donor ligands and their coordination compounds and the use of these ligands in the construction of coordination polymers and coordination polymer gels. The project can be divided into two parts. The first part of the research is focused on the coordination chemistry of ring-substituted biimidazoles in acidic media. The dependence of the formation of ion pairs and zwitterionic, especially zinc and copper containing coordination compounds on the pH of the reaction medium and ring-substituents of the ligand were examined. The second part of the study deals with the preparation of Ag, Zn and Cu coordination polymers…
Simultaneous Endo- and Exo-Complex Formation of Pyridine[4]arene Dimer with Neutral and Anionic Guests
2017
The formation of complexes between hexafluorophosphate (PF6−) and tetraisobutyloctahydroxypyridine[4]arene has been thoroughly studied in the gas phase (ESI‐QTOF‐MS, IM‐MS, DFT calculations), in the solid state (X‐ray crystallography), and in chloroform solution (1H, 19F, and DOSY NMR spectroscopy). In all states of matter, simultaneous endo complexation of solvent molecules and exo complexation of a PF6− anion within a pyridine[4]arene dimer was observed. While similar ternary complexes are often observed in the solid state, this is a unique example of such behavior in the gas phase. peerReviewed
Comment on “Crystallographic Snapshot of an Arrested Intermediate in the Biomimetic Activation of CO2”
2015
Out of focus: A recent Communication published in this journal describes the synthesis of [nBu4 N]HCO3 . The authors performed a single-crystal X-ray study that revealed a putative species described as an incipient hydroxide ion engaging in a long, and presumably weak, interaction with CO2 . Our recent exploration of the coordination chemistry of CO2 with small ions leads us to believe that such an exceptional bonding situation is unlikely. Instead, we argue that the crystal structure is that of [nBu4 N]O2 CCH3 and therefore not representative of the bulk powder from the synthesis.
Firsts lysidinyl- and lysidinium-triphosphines Pd(II) complexes
2010
International audience; The preparation of first lysidinyl-triphosphine ligand (named Triphosline) is described in three steps which are first a Michael type addition of imidazolidine (or lysidine) to diethylvinylphosphonate, second a phosphonate reduction with LiAlH4 and third an anti-Markovnikov radical addition of the primary phosphine to diphenylvinylphosphine. The Triphosline behaves as a tridentate P-coordinating ligand in palladium(II) complexes. The dangling lysidine function is then cleanly and totally alkylated by methyl iodide to lead to a new kind of lysidinium-triphosphine complexes. Subsequent anion exchange with TlPF6 affords the first example of a chloride free lysidinium-tr…