Results 61 to 70 of about 71,844 (227)
Transport Resistance Dominates the Fill Factor Losses in Record Organic Solar Cells
Advanced Energy Materials, EarlyView.Organic photovoltaics are a promising solar cell technology, but even the record devices with 20% efficiency have significant fill factor losses due to low active layer conductivities. In this Perspective, the authors describe the origin of these losses, discuss experimental methods for their quantification, and explain how to minimize them to optimize
Chen Wang +6 more
wiley +1 more source
ON-RECURRENT LORENTZIAN -KENMOTSU MANIFOLDS
Süleyman Demirel Üniversitesi Fen-Edebiyat Fakültesi Fen Dergisi, 2009 : In this paper, we study Lorentzian -Kenmotsu manifold and we shown that -recurrent Lorentzian -Kenmotsu manifold is an Einstein manifold and a pseudo-projective -recurrent Lorentzian -Kenmotsu manifold is an - Einstein manifold.
G.T. SREENIVASA +3 more
doaj
Einstein Manifolds As Yang-Mills Instantons
, 2013 It is well-known that Einstein gravity can be formulated as a gauge theory of Lorentz group where spin connections play a role of gauge fields and Riemann curvature tensors correspond to their field strengths.
Donaldson S. K. +6 more
core +1 more source
Isotropic quasi-Einstein manifolds [PDF]
Classical and Quantum Gravity, 2019 We investigate the local structure of four-dimensional Lorentzian quasi-Einstein manifolds under conditions on the Weyl tensor. We show that if the Weyl tensor is harmonic and the potential function preserves this harmonicity then, in the isotropic case, the manifold is necessarily a $pp$-wave. Using the quasi-Einstein equation, further conclusions are
M Brozos-Vázquez +2 more
openaire +3 more sources
Advanced Intelligent Discovery, EarlyView.Combining machine learning and probabilistic statistical learning is a powerful way to discover and design new materials. A variety of machine learning approaches can be used to identify promising candidates for target applications, and causal inference can help identify potential ways to make them a reality.
Jonathan Y. C. Ting, Amanda S. Barnard
wiley +1 more source
Remarks on the Myers-Perry and Einstein Gauss-Bonnet Rotating Solutions
, 2010 The Kerr-type solutions of the five-dimensional Einstein and Einstein-Gauss-Bonnet equations look pretty similar when written in Kerr-Schild form. However the Myers-Perry spacetime is circular whereas the rotating solution of the Einstein-Gauss-Bonnet ...
ANDRES ANABALÓN +5 more
core +3 more sources
On Four Dimensional Einstein Manifolds [PDF]
Communications, Faculty Of Science, University of Ankara Series A1Mathematics and Statistics, 1987 The paper contains an argument leading to a classification of Einstein four-manifolds with a 3-dimensional Abelian group of isometries, first established by Kasner in 1923.
openaire +4 more sources
Advanced Intelligent Discovery, EarlyView.Exosomes are emerging as powerful biomarkers for disease diagnosis and monitoring. This review highlights the integration of surface‐enhanced Raman spectroscopy with artificial intelligence to enhance molecular fingerprinting of exosomes. Machine learning and deep learning techniques improve spectral interpretation, enabling accurate classification of ...
Munevver Akdeniz +2 more
wiley +1 more source
On Compact Trans-Sasakian Manifolds
Advances in Mathematical Physics, 2022 We study 3-dimensional compact and simply connected trans-Sasakian manifolds and find necessary and sufficient conditions under which these manifolds are homothetic to Sasakian manifolds.
Ibrahim Al-Dayel, Sharief Deshmukh
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On normal homogeneous Einstein manifolds [PDF]
Annales scientifiques de l'École normale supérieure, 1985 The main result of the paper is the classification of compact connected simple Lie groups G with closed connected subgroups H such that the Riemannian metric on G/H induced by the Killing form of G is Einstein, while G acts almost effectively on G/H, G/H is simply connected and not strongly isotropy irreducible. For many classes of homogeneous Einstein
Wolfgang Ziller, McKenzie Y. Wang
openaire +3 more sources