scholarly journals Single-stage direct Langevin dynamic simulations of transitions over arbitrarily high energy barriers: Concept of energy-dependent temperature

2021 ◽  
Vol 104 (22) ◽  
Author(s):  
Dmitry Berkov ◽  
Elena K. Semenova ◽  
Natalia L. Gorn
Keyword(s):  
High Energy ◽  
Single Stage ◽  
Energy Barriers ◽  
Dynamic Simulations ◽  
Langevin Dynamic ◽  
Energy Dependent

Planar Dy3 + Dy3 clusters: design, structure and axial ligand perturbed magnetic dynamics

2015 ◽  
Vol 44 (47) ◽  
pp. 20316-20320 ◽  
Author(s):  
Xiao-Lei Li ◽  
Han Li ◽  
Di-Ming Chen ◽  
Chao Wang ◽  
Jianfeng Wu ◽  
...  
Keyword(s):  
Single Molecule ◽  
High Energy ◽  
Axial Ligand ◽  
Magnetic Behaviour ◽  
Energy Barriers ◽  
Magnetic Dynamics ◽  
Design Structure

Coupling Dy3 triangles results in two unique Dy6 complexes showing single-molecule magnetic behaviour with high energy barriers of 116 and 181 K for Dy6–NO3 and Dy6–SCN, respectively.

scholarly journals The Structural Evolution of Al86Ni9La5 Glassy Ribbons during Milling at Room and Cryogenic Temperatures

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1956
Author(s):  
Zhicheng Yan ◽  
Yan Liu ◽  
Shaopeng Pan ◽  
Yihua Hu ◽  
Jing Pang ◽  
...  
Keyword(s):  
Milling Time ◽  
Shear Bands ◽  
Structural Evolution ◽  
High Energy ◽  
Milling Process ◽  
Cryogenic Temperatures ◽  
Dynamic Simulations ◽  
Tricapped Trigonal Prism ◽  
Medium Range ◽  
Energy Ball

Melt-spun metallic Al86Ni9La5 glassy ribbons solidified at different circumferential speeds (Sc) were subjected to high-energy ball milling at room and cryogenic temperatures. Crystallization induced by milling was found in the Al86Ni9La5 solidified at lower circumferential speed (Sc = 14.7 m/s), while the Al86Ni9La5 with Sc = 36.6 m/s kept amorphous. Besides, a trend of structural rejuvenation during milling process was observed, as the onset temperatures (Tx1, Tx2) and the crystallization enthalpies (ΔH1, ΔH2) first decreased and then increased along with the milling time. We explored the structural origin of crystallization by ab initio molecular dynamic simulations and found that the tricapped trigonal prism (TTP) Ni-centered clusters with a higher frequency in samples solidified at a lower cooling rate, which tend to link into medium-range orders (MROs), may promote crystallization by initiating the shear bands during milling. Based on the deformation mechanism and crush of metallic glasses, we presented a qualitative model to explain the structural rejuvenation during milling.

scholarly journals Ultrafast charge transfer dynamics in 2D Covalent Organic Frameworks/Re-complex hybrid photocatalyst for CO2 reduction: hot electrons vs. cold electrons

2021 ◽  
Author(s):  
Qinying Pan ◽  
Mohamed Abdellah ◽  
Yuehan Cao ◽  
Yang Liu ◽  
Weihua Lin ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Excitation Energy ◽  
Co2 Reduction ◽  
Underlying Mechanism ◽  
High Energy ◽  
Hot Electrons ◽  
Covalent Organic Frameworks ◽  
Energy Excitation ◽  
Energy Dependent

Abstract Rhenium(I)-carbonyl-diimine complexes are promising photocatalysts for CO2 reduction. Covalent organic frameworks (COFs) can be perfect sensitizers to enhance the reduction activities. Here we investigated the excited state dynamics of COF (TpBpy) with 2,2'-bipyridine incorporating Re(CO)5Cl (Re-TpBpy) to rationalize the underlying mechanism. The time-dependent DFT calculation first clarified excited state structure of the hybrid catalyst. The studies from transient visible and infrared spectroscopies revealed the excitation energy-dependent photo-induced charge transfer pathways in Re-TpBpy. Under low energy excitation, the electrons at the LUMO level are quickly injected from Bpy into ReI center (1–2 ps) followed by backward recombination (13 ps). Under high energy excitation, the hot-electrons are first injected into the higher unoccupied level of ReI center (1–2 ps) and then slowly relax back to the HOMO in COF (24 ps). There also remains long-lived free electrons in the COF moiety. This explained the excitation energy-dependent CO2 reduction performance in our system.

European Energy Security and Sustainability

2011 ◽  
pp. 38-67
Author(s):  
Anatoly Zhuplev ◽  
Dmitry A. Shtykhno
Keyword(s):  
Energy Security ◽  
Oil And Gas ◽  
Sustainable Energy ◽  
High Energy ◽  
Energy Sector ◽  
Technology Investment ◽  
Regional Energy ◽  
Political Economic ◽  
Energy Dependent ◽  
The Eu

Europe’s economic wellbeing and growth are highly energy dependent and heavily reliant on Russian imports of oil and gas. European energy security, its alternatives, and implications are examined in this chapter with the view of sustainability and the EU-Russian energy dialog. With an asymmetric mutual political-economic interdependency with Russia, Europe’s exposure in oil and gas calls for sustainable energy solutions. Meantime, Russia, the key energy supplier in the European region, is also a major energy consumer whose economy is characterized by high energy intensity. Russian energy sector needs serious improvements in technology, investment, and management: failure to address these priorities erodes Russia’s reliability as major regional energy supplier. The chapter explores the dynamics of Russian energy sector and implications for European energy security and sustainability.

scholarly journals X-ray Spectral Evolution of High Energy Peaked Blazars

Galaxies ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 62
Author(s):  
Haritma Gaur
Keyword(s):  
High Energy ◽  
Energy Interval ◽  
Spectral Studies ◽  
Parabolic Model ◽  
Spectral Evolution ◽  
Spectral Variability ◽  
Spectral Parameters ◽  
X Ray ◽  
Wide Energy ◽  
Energy Dependent

The synchrotron hump of the high energy peaked blazars generally lies in the 0.1–10 keV range and such sources show extreme flux and spectral variability in X-ray bands. Various spectral studies showed that the X-ray spectra of high energy peaked blazars are curved and better described by the log-parabolic model. The curvature is attributed to the energy dependent statistical acceleration mechanism. In this work, we review the X-ray spectral studies of high energy peaked blazars. It is found that the log-parabolic model well describes the spectra in a wide energy interval around the peak. The log-parabolic model provides the possibility of investigating the correlation between the spectral parameters derived from it. Therefore, we compiled the studies of correlations between the various parameters derived from the log-parabolic model and their implications to describe the variability mechanism of blazars.

Energy-dependent nebula extent and spatially resolved spectra of the pulsar wind nebula 3C 58

2020 ◽  
Vol 498 (2) ◽  
pp. 1911-1919
Author(s):  
Fang-Wu Lu ◽  
Quan-Gui Gao ◽  
Li Zhang
Keyword(s):  
Surface Brightness ◽  
Spectral Energy Distribution ◽  
High Energy ◽  
Spatial Variations ◽  
Spectral Energy ◽  
X Ray ◽  
Spatially Resolved ◽  
Photon Index ◽  
Pulsar Wind ◽  
Energy Dependent

ABSTRACT 3C 58 is a pulsar wind nebula (PWN) that shows an interesting energy-dependent nebula extent and spatial variations of the photon index and surface brightness in the X-ray band. These observations provide useful information with which to study the spatially dependent radiative cooling of electrons and the energy-dependent transport mechanisms within the nebula. In this paper, the energy-dependent nebula extent and spatially resolved spectra of this PWN are investigated in the framework of a spatially dependent particle transport model. The observations of the nebula, including the photon spectral energy distribution, spatial variations of the X-ray spectrum, and measurements of the nebula extent, can be naturally explained in this model. Our results show that the energy-dependent nebula extent favours an advection–diffusion scenario with advection-dominated transport, and the variations of the nebula extent with energy in the X-ray band can be attributed to the cooling losses of high-energy electrons affected by synchrotron burn-off. Particle diffusion plays an important role in modifying the spatial variations of the photon index and surface brightness in the X-ray band. The radial extents of the nebula at radio, GeV and TeV energies are predicted by the model, indicating that the nebula extent of 3C 58 varies with energy in these bands. The analyses show that the dependence of the adiabatic cooling rate and synchrotron radiation on the spectral index of injected particles is important for changing the nebula extent at different energies.

Sign in / Sign up

Export Citation Format

Share Document