Search results for " coupling"
showing 10 items of 724 documents
[Mnii2(bpym)(H2O)8]4+ and [Miv(CN)8]4– (M = Mo and W) as building blocks in designing bpym- and cyanide-bridged bimetallic three-dimensional networks…
2002
One-pot reaction between the dinuclear [MnII2(bpym)(H2O)8]4+ complex and the mononuclear [MIV(CN)8]4− unit (M = Mo and W; bpym = 2,2′-bipyrimidine) in aqueous solution yields the novel heterobimetallic complexes of formula {(μ-bpym)[Mn(H2O)]2-(μ-NC)6M(CN)2} with M = Mo (1) and W (2). 1 and 2 are isostructural three-dimensional compounds where the manganese atoms are bridged by bisbidentate bpym and hexakismonodentate octacyanometalate units. Variable-temperature magnetic susceptibility data of 1 and 2 show the occurrence of a significant antiferromagnetic coupling between the high spin manganese(II) ions through bridging bpym (Jca. −1.1 cm−1, the exchange Hamiltonian being defined as H = −J…
Oxidative transformation of aryls using molybdenum pentachloride.
2012
Molybdenum pentachloride combines a strong Lewis acid character with an unusually high oxidation potential creating a powerful reagent for oxidative transformations. Since the oxidative coupling reaction of aryls is induced at an extraordinarily high reaction rate, a variety of labile groups, e.g. iodo, tert-alkyl, etc., are tolerated on the aromatic core. Furthermore, the co-formed molybdenum salts can either be exploited for template effects to obtain uncommon geometries in a preferred manner, or redox-play starts after aqueous workup. Therefore MoCl(5) represents a unique and easily available reagent.
Intersystem crossing in Fe(II) coordination compounds
1994
Fe(II) spin-crossover systems can be quantitatively converted from the low-spin (LS) to the high-spin (HS) state well below the thermal transition temperature by irradiating either into the metal-ligand charge transfer or d-d absorption bands, and even in low-spin systems a transient population of the HS state can be achieved. This fact can be made use of to determine HS → LS relaxation rate constants for a wide variety of Fe(II) spin-crossover and low-spin systems. The HS → LS relaxation shows strong deviations from an Arrhenius behaviour, with nearly temperature-independent tunnelling below ∼70 K and a thermally activated process above ∼100 K. The range of more than 12 orders of magnitude…
Phonon coupling of non-bridging oxygen hole center with the silica environment: Temperature dependence of the 1.9 eV emission spectra
2008
Abstract We report an experimental study on the shape of the 1.9 eV emission associated with non-bridging oxygen hole centers in silica and its temperature dependence, from 4 up to 300 K, under visible and ultraviolet excitation. Our analysis points out that these defects are coupled with their environment by phonons whose contribution can be described by the single mode of mean frequency between 300–400 cm −1 and Huang–Rhys factor of ∼3. On increasing the temperature, the luminescence intensity undergoes a thermal quenching caused by non-radiative processes, its deviation from a pure Arrhenius law can be accounted for by an uniform distribution of activation energy, from 0.002 to 0.05 eV. …
Measurement of untruncated nuclear spin interactions via zero- to ultralow-field nuclear magnetic resonance
2015
Zero- to ultra-low-field nuclear magnetic resonance (ZULF NMR) provides a new regime for the measurement of nuclear spin-spin interactions free from effects of large magnetic fields, such as truncation of terms that do not commute with the Zeeman Hamiltonian. One such interaction, the magnetic dipole-dipole coupling, is a valuable source of spatial information in NMR, though many terms are unobservable in high-field NMR, and the coupling averages to zero under isotropic molecular tumbling. Under partial alignment, this information is retained in the form of so-called residual dipolar couplings. We report zero- to ultra-low-field NMR measurements of residual dipolar couplings in acetonitrile…
FT Raman and DFT Study on a Series of All-antiOligothienoacenes End-Capped with Triisopropylsilyl Groups
2009
minal a positions. These substituents aid in purification and solution processability, and can be removed under mild chemical conditions. For the first time, we have the opportunity to analyze a series of oligothienoacenes to gain insight into the fundamental structure–property relationships with respect to the addition of each ring. Furthermore, this series of compounds can be directly compared to other well-studied series of closely related oligomers, such as nonfused oligothiophenes and fully fused all-syn oligothienoacenes. [7] To gain precise insight into relationships between the structure and properties of a wide range of p-conjugated molecular Herein, we study the p-conjugational pr…
Ambiguities in organizations and the routines of behavior and change
2015
Purpose– The aim of this article is threefold: the primary aim is conceptual by outlining two ideal-typical ideas about organizational life. These models offer rival ideas about how organizations balance seemingly conflicting patterns of behaviour and change in everyday life. The second ambition of the article is to outline a theoretical approach of organizational life arguing that even fairly loosely coupled organizations may be profoundly patterned by everyday routines as much as by ambiguity. The third and final ambition is to offer empirical illustrations from organizations that are often considered as archetypes of loose coupling and ambiguities: jazz orchestras and university organiza…
A Small Power Transmission Prototype for Electric Vehicle Wireless Battery Charge Applications
2012
In this paper a low cost prototype of wireless power transfer system based on air coupling is presented. The system here proposed can be useful for electric vehicle (EV) battery charging systems. It consists mainly of two copper wire coils, placed one in front of the other on the same axis. The inductor coil can easily be placed under the road surface (in a parking), while the other (the receiver coil) in the lower side of the vehicle. By exploiting the coils resonance coupling effect, electric energy can be transferred from the inductor coil to the receiver in order to charge the batteries. Low cost experimental tests carried out at DIEETCAM - University of Palermo, demonstrated the effect…
Investigation of inductive coupling solutions for E-bike wireless charging
2015
Wireless charging of electric vehicle batteries is a major topic for academic and industrial research. The wireless charging is based on the inductive coupling between a primary coil, connected to the grid, and a secondary coil, connected to the vehicle battery. Wireless battery charging provides benefits in terms of comfort for the drivers, who should just park to start the charging operation, without needing to plug in the vehicle. Wireless charging is particularly convenient for E-bike users. For the bicycle charging, the inductive coupling should be implemented through a compact and light-weight solution. In this paper, different options of inductively coupled coils for E- bike charging…
Wireless Power Transmission for house appliances: A small-scale resonant coupling prototype
2016
This paper presents a low cost prototype of wireless power transfer system based on resonant coupling. The system here proposed can be useful for house appliances battery charging systems: as a matter of fact, it consists mainly of two copper wire coils or windings, placed one in front of the other on the same axis. By exploiting the coils resonance coupling effect, electric energy can be transferred from the inductor coil to the receiver in order to charge the batteries. Low cost experimental tests demonstrated the effectiveness of the proposed wireless power transfer prototype, being it capable to reach an efficiency of about 80% and more along a distance of 30 cm.