Search results for "Coupling"
showing 10 items of 1862 documents
ChemInform Abstract: Selective Synthesis of Partially Protected Nonsymmetric Biphenols by Reagent- and Metal-Free Anodic Cross-Coupling Reaction.
2016
The oxidative cross-coupling of aromatic substrates without the necessity of leaving groups or catalysts is described. The selective formation of partially protected nonsymmetric 2,2'-biphenols via electroorganic synthesis was accomplished with a high yield of isolated product. Since electric current is employed as the terminal oxidant, the reaction is reagent-free; no reagent waste is generated as only electrons are involved. The reaction is conducted in an undivided cell, and is suitable for scale-up and inherently safe. The implementation of O-silyl-protected phenols in this transformation results in both significantly enhanced yields and higher selectivity for the desired nonsymmetric 2…
Strong-coupling expansions for the -symmetric oscillators
1998
We study the traditional problem of convergence of perturbation expansions when the hermiticity of the Hamiltonian is relaxed to a weaker symmetry. An elementary and quite exceptional cubic anharmonic oscillator is chosen as an illustrative example of such models. We describe its perturbative features paying particular attention to the strong-coupling regime. Efficient numerical perturbation theory proves suitable for such a purpose.
Inner Edge Drag by an Asynchronous Primary and Accretion Disc Structure In Close Binaries
1996
In this work a 3-D ‘Smoothed Particle Hydrodynamics’ ([1]; [4]; [5]) accretion disc is simulated where particles at its inner edge are dragged by a fast spinning compact central star, as in the case of the intermediate polars. The angular velocity of the central star is twice the orbital angular velocity w 0. This drag can be attributed mainly to viscous interaction in the dense compact star atmosphere, although magnetic coupling may also play a role.
Digitalized bioeconomy: Planned obsolescence-driven circular economy enabled by Co-Evolutionary coupling
2019
Driven by digital solutions, the bioeconomy is taking major steps forward in recent years toward achievement of the long-lasting goal of transition from a traditional fossil economy to a bioeconomy-based circular economy. The coupling of digitalization and bioeconomy is leading towards a digitalized bioeconomy that can satisfy the shift in consumers’ preferences for eco-consciousness, which in turn induces coupling of up-down stream operation in the value chain. Thus, the co-evolution of the coupling of digitalization and bioeconomy and of upstream and downstream operations is transforming the forest-based bioeconomy into a digital platform industry. Aiming at addressing this transformation…
Co-evolutionary coupling leads a way to a novel concept of R&D - Lessons from digitalized bioeconomy
2020
Given the increasing role of research and development (R&D) in competitive markets in the digital economy while confronting the dilemma between R&D expansion and a productivity decline, transformation of the R&D model has become a crucial subject for global digital leaders. The authors of this paper postulate that neo open innovation harnessing the vigor of external innovation resources which then developed into a new concept of R&D that self-transforms during an R&D process initiated by Amazon by coupling with users. The authors further develop these postulates by proposing the embedding of a growth characteristic identical to biological coupling. An empirical analysis focusing on the fore…
Case studies and coupling of processes
2007
This chapter with eight authored sections presents a selection of possible application of microdynamic simulation to address geological questions. The various processes that have been introduced in the previous chapter were used, sometimes with minor additions or modifications. Because processes in rocks never operate in isolation, the reader will see that the various authors in this chapter have combined two or more processes to simulate the microstructural development under investigation. As such the authors have fully taken advantage of the possibility of the Elle software to couple processes.
Numerical modeling of the solid-state sintering at the microstructural level: Multiphysics approach and application to metal additive manufacturing
2023
Numerical modeling of the solid-state sintering at the microstructural level: Multiphysics approach and application to metal additive manufacturing
A microscopic monomeric mechanism for interpreting intrinsic optical bistability observed in Yb3+-doped bromide materials
2004
We present a mechanism able to show intrinsic bistable behaviour involving single Yb3+ ions embedded into bromide lattices, in which intrinsic optical bistability (IOB) has been observed. The mechanism is based on the experimentally found coupling between the Yb3+ ion and the totally symmetric local mode of vibration of the [YbBr6]3- coordination unit. The model reproduces the IOB observed in CsCdBr3:1% Yb3+ and allows to understand the experimentally found presence of the phenomenon in the other bromides, but its absence in Cs3Lu2Cl9:Yb3+.
Rôle des espèces sulfures dans la corrosion des aciers non alliés : hétérogénéités de la couche de produits de corrosion et couplages galvaniques
2014
The present study relates to the problem of the long-term interim storage of nuclear wastes. In France, it is envisaged that high-level radioactive wastes will be confined in a glass matrix, stored in a stainless steel canister, itself placed in a carbon steel overpack. The wastes will then be stored at a depth of ~450 m in a deep geological disposal, drilled in a very stiff (indurated) clay (argillite) formation. A temperature as high as 90°C is expected at the steel surface because of the intense radioactivity. Anodic polarization at applied current density was used to synthetize corrosion product layers likely to be formed in storage conditions. The S235 steel electrodes were covered by …
Polystyrene-supported organocatalysts for α-selenenylation and Michael reactions
2011
Abstract Three different resin-supported catalysts have been prepared by using the well established post-modification approach by means of thiol-ene coupling reaction. Two catalysts were tested for the first time in the asymmetric α-selenenylation of propanal, while the third catalyst was used in the Michael addition reaction. While the preliminary results are not encouraging in the case of supported Jorgensen’ catalyst, interesting data have been collected with both for the supported MacMillan and prolyl-prolinol catalysts. In fact, these catalysts displayed good activity and selectivity. A reversed enantioselectivity in the α-selenenylation was observed by changing the polarity of the sol…