Search results for "figuration"
showing 10 items of 615 documents
Crystallography of encapsulated molecules.
2017
The crystallography of supramolecular host–guest complexes is reviewed and discussed as a part of small molecule crystallography. In these complexes, the host binds the guests through weak supramolecular interactions, such as hydrogen and halogen bonding, cation–π, anion–π, C–H–π, π–π, C–H–anion interactions and the hydrophobic effect. As the guest often shows severe disorder, large thermal motion and low occupancies, the reliable crystallographic determination of the guest can be very demanding. The analysis of host–guest interactions using tools such as Hirshfeld and cavity volume surface analysis will help to look closely at the most important host–guest interactions. The jewel in the cr…
Elementary presentation of self‐consistent intermediate Hamiltonians and proposal of two totally dressed singles and doubles configuration interactio…
1994
Intermediate Hamiltonians are effective Hamiltonians which are defined on an N‐dimensional model space but which only provide n<N exact eigenvalues and the projections of the corresponding eigenvectors onto the model space. For a single root research, the intermediate Hamiltonian may be obtained from the restriction of the Hamiltonian to the model space by an appropriate, uniquely defined dressing of the diagonal energies or of the first column. Approximate self‐consistent dressings may be proposed. The simplest perturbative form gives the same result as the original 2nd order intermediate Hamiltonian or the ‘‘shifted Bk’’ technique but it is of easier implementation. Self‐consistent inclus…
Resting the mind – A novel topic with scarce insights. Considering potential mental recovery strategies for short rest periods in sports
2019
Abstract Both meticulously structured trainig routine as well as specific characteristics of various sports (e.g., swimming, shooting, modern pentathlon) with multiple competition bouts in a single day appear to be mentally demanding and may result in a state of mental fatigue. Due to these multidimensional demands, adequate training and competition recovery is essential. Consequently, the idea of mental recovery embraces the spotlight of research. On training and competition days, short rest periods implemented as a vital part, can be used for mental recovery and can help in assisting athletes to return to baseline levels of mental abilites (e.g., concentration, attention). Sport-specific …
Root Canal Morphology and Configuration of the Mandibular Canine: A Systematic Review
2021
The aim of this study was to systematically review the root canal morphology and configuration (RCC) of mandibular canines (MaCa). The review was registered in the PROSPERO database (ID-272297) and it was carried out following the PRISMA guidelines. Three electronic databases (MEDLINE via PubMed, Embase, Scopus) were searched. Randomized controlled trials, cross-sectional, cohort, comparative, evaluation and validation studies have been included. The anatomical quality assessment (AQUA) tool was used for a quality assessment of the anatomical studies. Of 910 studies retrieved from the systematic search, 28 studies investigating RCCs were included. Most MaCa were single-rooted (87.9–100%), w…
Coordinate space calculation of two- and three-loop sunrise-type diagrams, elliptic functions and truncated Bessel integral identities
2019
We integrate three-loop sunrise-type vacuum diagrams in $D_0=4$ dimensions with four different masses using configuration space techniques. The finite parts of our results are in numerical agreement with corresponding three-loop calculations in momentum space. Using some of the closed form results of the momentum space calculation we arrive at new integral identities involving truncated integrals of products of Bessel functions. For the non-degenerate finite two-loop sunrise-type vacuum diagram in $D_0=2$ dimensions we make use of the known closed form $p$-space result to express the moment of a product of three Bessel functions in terms of a sum of Claussen polylogarithms. Using results fo…
Multiplet coupling and band structure in L2,3-edge XAS through multi-channel multiple scattering theory.
2009
International audience; Using the recently developed multi-channel multiple scattering (MCMS) method we have calculated the x-ray absorption spectra (XAS) at the L2,3-edge of transition metal compounds. The MCMS method is an ab initio scheme which combines an accurate description of the band structure of the material with a correlated many-electron wave function on the absorber atom. Thereby configuration interaction in the XAS final state, in particular multiplet effects, can be taken into account. In the present implementation, we use an electron-hole wave function and treat the interaction with all other electrons on a mean-field level. The calculated spectra agree well with experiment f…
Resolution of β-aminophosphines with chiral cyclopalladated complexes
2005
Abstract Resolution of the racemic chiral β-aminophosphines Ph 2 PCH 2 CH(Ph)NH(Ar) ( L 1 for Ar = C 6 H 5 and L 2 for Ar = 2,6-C 6 H 3 i Pr 2 ) has been investigated by use of different cyclopalladated complexes as chiral agents. The resulting complexes afford diastereomeric adducts in a 1:1 ratio. After successive crystallizations from ethanol, a d.e. of 98% was achieved for one aminophosphine palladium complex, while no significant d.e. was obtained after crystallizations from chlorinated solvents. The X-ray structure analysis has pointed out intermolecular hydrogen interactions N–H⋯Cl between the P,N ligand and the chloride ion, which are responsible for the formation and stabilization …
Preparation and structure of the 17-electron (η5-C5R5)Mo(OH)2(dppe) (R=Me, Et) organometallic compounds containing two gem-terminal hydroxide ligands
2000
International audience; Oxidation of (η5-C5R5)MoH3(dppe) (R=Me, Et) by Cp2Fe+ in wet THF leads to the formation of the corresponding (η5-C5R5)Mo(OH)2(dppe). These compounds show a low-potential reversible oxidation wave. The structure of the C5Et5 complex has been confirmed by X-ray diffraction methods: triclinic; space group ; a=11.030(1); b=12.533(1); c=16.241 (1) Å; α=68.585(7); β=75.197(5); γ=83.991(7)°; V=2020.6(3) Å3; Z=2; Dcalc=1.324 g cm−3, μ(Mo–Kα)=0.441 mm−1; R1=0.0325; wR2=0.0875 for 415 parameters and 6823 independent reflections [Rint=0.0177] with I=2σ(I). The molecule shows a four-legged piano-stool geometry with two terminal OH ligands in a relative trans configuration. The c…
An MDE Approach for Rapid Prototyping and Implementation of Dynamic Reconfigurable Systems
2015
This article presents a co-design methodology based on RecoMARTE, an extension to the well-known UML MARTE profile, which is used for the specification and automatic generation of Dynamic and Partially Reconfigurable Systems-on-Chip (DRSoC). This endeavor is part of a larger framework in which Model-Driven Engineering (MDE) techniques are extensively used for modeling and via model transformations, generating executable models, which are exploited by implementation tools to create reconfigurable systems. More specifically, the methodological aspects presented in this article are concerned with expediting the conception and implementation of the hardware platform and the integration of corre…
ITIL rīki IT pārvaldībā
2020
Maģistra darbā tiek apskatīti nosacījumi labas IT pārvaldības nodrošināšanai, vadoties pēc ITIL pamatprincipiem. Darbā tiek praktiski analizēti IT pārvaldības nodrošināšanas paņēmieni trīs reālos uzņēmumos. Analīzes rezultātā tiek veidoti un ieviesti pielāgojumi uzņēmumos esošajiem rīkiem, lai nodrošinātu IT pārvaldības atbilstību ITIL labajai praksei, un praktiski izstrādāti pielāgojumi, kuru ieviešanu var plānot nākotnē. Pielāgojumu plānošanas un ieviešanas rezultāti darba noslēgumā pamato ITIL rīku nepieciešamību un to pielāgošanu veiksmīgas IT pārvaldības nodrošināšanai uzņēmumos. Gan darba teorētiskās, gan praktiskās daļas pamatā ir izmantotas ITIL labās prakses vadlīnijas.