Thermal Rate Constants for the O(3P) + CH4 → OH + CH3 Reaction: The Effects of Quantum Tunneling and Potential Energy Barrier Shape

2016 ◽  
Vol 120 (39) ◽  
pp. 7589-7597 ◽  
Author(s):  
Huali Zhao ◽  
Wenji Wang ◽  
Yi Zhao
Keyword(s):  
Potential Energy ◽  
Rate Constants ◽  
Quantum Tunneling ◽  
Energy Barrier ◽  
Potential Energy Barrier ◽  
Thermal Rate Constants

Hybrid-Bistable Vibration Energy Harvester With Adaptive Potential Well

2018 ◽  
Author(s):  
Jinki Kim ◽  
Patrick Dorin ◽  
K. W. Wang
Keyword(s):  
Energy Harvesting ◽  
Potential Energy ◽  
Cantilever Beam ◽  
Potential Barrier ◽  
Energy Barrier ◽  
Electrical Power ◽  
Vibration Energy ◽  
Frequency Spectra ◽  
Potential Energy Barrier ◽  
Piezoelectric Energy

Many common environmental vibration sources exhibit low and broad frequency spectra. In order to exploit such excitations, energy harvesting architectures utilizing nonlinearity, especially bistability, have been widely studied since the energetic interwell oscillations between their stable equilibria can provide enhanced power harvesting capability over a wider bandwidth compared to the linear counterpart. However, one of the limitations of these nonlinear architectures is that the interwell oscillation regime may not be activated for a low excitation level that is not strong enough to overcome the potential energy barrier, thus resulting in low amplitude intrawell response which provides poor energy harvesting performance. While the strategic integration of bistability and additional dynamic elements has shown potential to improve broadband energy harvesting performance by lowering the potential barrier, there is a clear opportunity to further improve the energy harvesting performance by extracting electrical power from the kinetic energy in the additional element that is induced when the potential barrier is lowered. To explore this opportunity and advance the state of the art, this research develops a novel hybrid bistable vibration energy harvesting system with a passive mechanism that not only adaptively lowers the potential energy barrier level to improve broadband performance but also exploits additional means to capture more usable electrical power. The proposed harvester is comprised of a cantilever beam with repulsive magnets, one attached at the free end and the other attached to a linear spring that is axially aligned with the cantilever (a spring-loaded magnet oscillator). This new approach capitalizes on the adaptive bistable potential that is passively realized by the spring-loaded magnet oscillator, which lowers the double-well potential energy barrier thereby facilitating the interwell oscillations of the cantilever across a broad range of excitation conditions, especially for low excitation amplitudes and frequencies. The interwell oscillation of the cantilever beam enhances not only the piezoelectric energy harvesting from the beam but also the electromagnetic energy harvesting from the spring-loaded magnet oscillator by inducing large amplitude vibrations of the magnet oscillator. Numerical investigations found that the proposed architecture yields significantly enhanced energy harvesting performance compared to the conventional bistable harvester with fixed magnet.

Potential Energy Barrier to Rotation in Methyl Nitrite Measured by PMR

1960 ◽  
Vol 32 (6) ◽  
pp. 1878-1880 ◽  
Author(s):  
Peter Gray ◽  
Leonard W. Reeves
Keyword(s):  
Potential Energy ◽  
Energy Barrier ◽  
Methyl Nitrite ◽  
Potential Energy Barrier

scholarly journals The enzyme aromatic amine dehydrogenase induces a substrate conformation crucial for promoting vibration that significantly reduces the effective potential energy barrier to proton transfer

2008 ◽  
Vol 5 (suppl_3) ◽  
pp. 225-232 ◽  
Author(s):  
Linus O Johannissen ◽  
Nigel S Scrutton ◽  
Michael J Sutcliffe
Keyword(s):  
Potential Energy ◽  
Proton Transfer ◽  
Aromatic Amine ◽  
Effective Potential ◽  
Energy Barrier ◽  
Transfer Event ◽  
Effective Potential Energy ◽  
Potential Energy Barrier ◽  
Mechanical Methods ◽  
Amine Dehydrogenase

The role of promoting vibrations in enzymic reactions involving hydrogen tunnelling is contentious. While models incorporating such promoting vibrations have successfully reproduced and explained experimental observations, it has also been argued that such vibrations are not part of the catalytic effect. In this study, we have employed combined quantum mechanical/molecular mechanical methods with molecular dynamics and potential energy surface calculations to investigate how enzyme and substrate motion affects the energy barrier to proton transfer for the rate-limiting H-transfer step in aromatic amine dehydrogenase (AADH) with tryptamine as substrate. In particular, the conformation of the iminoquinone adduct induced by AADH was found to be essential for a promoting vibration identified previously—this lowers significantly the ‘effective’ potential energy barrier, that is the barrier which remains to be surmounted following collective, thermally equilibrated motion attaining a quantum degenerate state of reactants and products. When the substrate adopts a conformation similar to that in the free iminoquinone, this barrier was found to increase markedly. This is consistent with AADH facilitating the H-transfer event by holding the substrate in a conformation that induces a promoting vibration.

Reduction of the potential energy barrier and resistance at wafer-bondedn-GaAs/n-GaAs interfaces by sulfur passivation

2011 ◽  
Vol 110 (10) ◽  
pp. 104903 ◽  
Author(s):  
Michael J. Jackson ◽  
Biyun L. Jackson ◽  
Mark S. Goorsky
Keyword(s):  
Potential Energy ◽  
Energy Barrier ◽  
Potential Energy Barrier ◽  
Sulfur Passivation

Potential Energy Barrier Determinations for Some Alkyl Nitrites by Nuclear Magnetic Resonance

1959 ◽  
Vol 30 (4) ◽  
pp. 899-908 ◽  
Author(s):  
Lawrence H. Piette ◽  
Weston A. Anderson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Potential Energy ◽  
Energy Barrier ◽  
Alkyl Nitrites ◽  
Potential Energy Barrier ◽  
Nuclear Magnetic

The potential energy barrier of the state in KLi

2009 ◽  
Vol 73 (1) ◽  
pp. 117-120 ◽  
Author(s):  
W. Jastrzebski ◽  
P. Kowalczyk ◽  
A. Pashov ◽  
J. Szczepkowski
Keyword(s):  
Potential Energy ◽  
Energy Barrier ◽  
The State ◽  
Potential Energy Barrier

Viscous Liquids and the Glass Transition: A Potential Energy Barrier Picture

1969 ◽  
Vol 51 (9) ◽  
pp. 3728-3739 ◽  
Author(s):  
Martin Goldstein
Keyword(s):  
Glass Transition ◽  
Potential Energy ◽  
Energy Barrier ◽  
Viscous Liquids ◽  
Potential Energy Barrier
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