Results 81 to 90 of about 45,346 (288)

Demonstration of Focusing Wolter Mirrors for Neutron Phase and Magnetic Imaging

Journal of Imaging, 2018
Image-forming focusing mirrors were employed to demonstrate their applicability to two different modalities of neutron imaging, phase imaging with a far-field interferometer, and magnetic-field imaging through the manipulation of the neutron beam ...
Daniel S. Hussey, Han Wen, Huarui Wu, Thomas R. Gentile, Wangchun Chen, David L. Jacobson, Jacob M. LaManna, Boris Khaykovich   +7 more
doaj   +1 more source

Cosmological deformation of Lorentzian spin foam models [PDF]

Classical and Quantum Gravity, 2003
We study the quantum deformation of the Barrett-Crane Lorentzian spin foam model which is conjectured to be the discretization of Lorentzian Plebanski model with positive cosmological constant and includes therefore as a particular sector quantum gravity in de-Sitter space.
Roche, Philippe, Noui, K.
openaire   +4 more sources

Atomic Size Misfit for Electrocatalytic Small Molecule Activation

Advanced Functional Materials, EarlyView.
This review explores the application and mechanisms of atomic size misfit in catalysis for small molecule activation, focusing on how structural defects and electronic properties can effectively lower the energy barriers of chemical bonds in molecules like H2O, CO2, and N2.
Ping Hong, Changfan Xu, Huaping Zhao, Yong Lei   +3 more
wiley   +1 more source

Discrete Gravity Models and Loop Quantum Gravity: a Short Review

Symmetry, Integrability and Geometry: Methods and Applications, 2012
We review the relation between Loop Quantum Gravity on a fixed graph and discrete models of gravity. We compare Regge and twisted geometries, and discuss discrete actions based on twisted geometries and on the discretization of the Plebanski action.
Simone Speziale, James P. Ryan, Maïté Dupuis   +2 more
doaj   +1 more source

A New Spin Foam Model for 4d Gravity

, 2008
Starting from Plebanski formulation of gravity as a constrained BF theory we propose a new spin foam model for 4d Riemannian quantum gravity that generalises the well-known Barrett-Crane model and resolves the inherent to it ultra-locality problem.
Alexandrov S, Ashtekar A, Baez J C, Baez J C, Baratin A, Barrett J W, Barrett J W, Buffenoir E, Capovilla R, De Pietri R, Engle J Livine E Pereira R Rovelli C, Engle J Pereira R Rovelli C, Freidel L, Freidel L, Freidel L, Gelfand I M, Kirill Krasnov, Laurent Freidel, Livine E R Speziale S, Perelomov A, Ponzano G, Reisenberger M P, Reisenberger M P   +22 more
core   +1 more source

Copper‐based Materials for Photo and Electrocatalytic Process: Advancing Renewable Energy and Environmental Applications

Advanced Functional Materials, EarlyView.
Cu‐based catalysts as a cornerstone in advancing sustainable energy technologies are fully reviewed in this manuscript, highlighting their potential in photo‐ and electrocatalysis. It includes metallic copper, copper oxides, copper sulfides, copper halide perovskites, copper‐based metal–organic frameworks (MOFs), and covalent organic frameworks (COFs),
Jéssica C. de Almeida, Yanjie Wang, Thais A. Rodrigues, Paulo H. H. Nunes, Vagner R. de Mendonça, Paulo H. E. Falsetti, Leticia V. Savazi, Tao He, Alexandra V. Bardakova, Aida V. Rudakova, Jie Tian, Alexei V. Emeline, Osmando F. Lopes, Antonio Otavio T. Patrocínio, Jia Hong Pan, Caue Ribeiro, Detlef W. Bahnemann   +16 more
wiley   +1 more source

Quantum group spin nets: refinement limit and relation to spin foams

, 2014
So far spin foam models are hardly understood beyond a few of their basic building blocks. To make progress on this question, we define analogue spin foam models, so called spin nets, for quantum groups $\text{SU}(2)_k$ and examine their effective ...
Dittrich, Bianca, Martin-Benito, Mercedes, Steinhaus, Sebastian   +2 more
core   +1 more source

Hydrogen‐Bubble Repellent Conjugated Polymeric Coating for Improving Electrochemical Hydrogen Evolution.

Advanced Functional Materials, EarlyView.
A hydrogen‐bubble repellent conjugated polymeric coating improves an electrochemical hydrogen evolution reaction maintaining a lower overpotential, a highly electrochemically active surface area and smaller Tafel slope. While the hydrogen‐bubble repellence because of polyglycerol moiety ensures an early detachment of produced hydrogen gas bubbles, the ...
Jaysri Das, Esra Özdemir, Hrisikesh Sarma, Andreas Terfort, Uttam Manna   +4 more
wiley   +1 more source

Effective action and semiclassical limit of spin foam models

, 2011
We define an effective action for spin foam models of quantum gravity by adapting the background field method from quantum field theory. We show that the Regge action is the leading term in the semi-classical expansion of the spin foam effective action ...
A Miković, Abbot L, Baez J C, Barrett J W, Barrett J W, Barrett J W Dowdall R J Fairbairn W J Hellmann F Pereira R, Bianchi E, Fairbairn W Meusburger C, Freidel L, M Vojinović, Magliaro E, Makela J, Miković A, Miković A, Miković A, Miković A Vojinović M, Miković A Vojinović M   +16 more
core   +1 more source

State‐of‐the‐Art, Insights, and Perspectives for MOFs‐Nanocomposites and MOF‐Derived (Nano)Materials

Advanced Materials, EarlyView.
Different approaches to MOF‐NP composite formation, such as ship‐in‐a‐bottle, bottle‐around‐the‐ship and in situ one‐step synthesis, are used. Owing to synergistic effects, the advantageous features of the components of the composites are beneficially combined, and their individual drawbacks are mitigated.
Stefanos Mourdikoudis, Subhajit Dutta, Saqib Kamal, Sergio Gómez‐Graña, Isabel Pastoriza‐Santos, Stefan Wuttke, Lakshminarayana Polavarapu   +6 more
wiley   +1 more source