scholarly journals Breaking the disulfide chemical bond using high energy photons: the dimethyl disulfide and methyl propyl disulfide molecules

RSC Advances ◽  
2017 ◽  
Vol 7 (58) ◽  
pp. 36525-36532 ◽  
Author(s):  
L. R. Varas ◽  
L. H. Coutinho ◽  
R. B. Bernini ◽  
A. M. Betancourt ◽  
C. E. V. de Moura ◽  
...  
Keyword(s):  
Chemical Bond ◽  
Dimethyl Disulfide ◽  
High Energy ◽  
Ionic Fragmentation ◽  
The Stability ◽  
Methyl Propyl Disulfide

In order to study the stability of the disulfide chemical bond in molecules subjected to a flux of high energy photons, the ionic fragmentation of DMDS and MPDS has been studied following excitation around the S 1s edge (∼2470 eV).

scholarly journals Carbon Substitution on N24Cages: Crossover between Triangular and Hexagonal Structures

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Carrie Sanders ◽  
Douglas L. Strout
Keyword(s):  
Theoretical Calculations ◽  
High Energy ◽  
Energy Materials ◽  
Cylindrical Structures ◽  
High Energy Materials ◽  
Energy Applications ◽  
Carbon Substitution ◽  
Complex Forms ◽  
The Stability ◽  
Carbon Inclusion

Complex forms of nitrogen are of interest for their potential as high-energy materials, but many all-nitrogen systems lack the stability for practical high-energy applications. Inclusion of carbon atoms in an otherwise all-nitrogen structure can increase stability. Nitrogen cages are known for energetically preferring cylindrical structures with triangular endcaps, but carbon cages prefer the pentagon-hexagon structure of the fullerenes. Previous calculations on N22C2have shown that carbon inclusion narrows the gap between triangular and fullerene-like structures. In the current study, three isomers of N24are used as frameworks for carbon substitution. Theoretical calculations are carried out on isomers of N20C4, N18C6, and N16C8, with the goal of determining what level of carbon substitution causes the carbon fullerene-like structures to become energetically preferred.

Electrochemical lithium recovery with lithium iron phosphate: What causes performance degradation and how can we improve the stability?

2021 ◽  
Author(s):  
Lei Wang ◽  
Kathleen C Frisella ◽  
Pattarachai Srimuk ◽  
Oliver Janka ◽  
Guido Kickelbick ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Manganese Oxide ◽  
Lithium Iron Phosphate ◽  
Iron Phosphate ◽  
High Energy ◽  
Performance Degradation ◽  
Electrochemical Processes ◽  
High Energy Efficiency ◽  
The Stability

Electrochemical processes enable fast lithium extraction, for example, from brines, with high energy efficiency and stability. Lithium iron phosphate (LiFePO4) and manganese oxide (λ-MnO2) have usually been employed as the...

Scanning system for high-energy electron diffractometry

1999 ◽  
Vol 32 (6) ◽  
pp. 1033-1038 ◽  
Author(s):  
A. S. Avilov ◽  
A. K. Kuligin ◽  
U. Pietsch ◽  
J. C. H. Spence ◽  
V. G. Tsirelson ◽  
...  
Keyword(s):  
High Energy ◽  
Scanning System ◽  
Registration System ◽  
Hartree Fock ◽  
Intensity Measurements ◽  
Structure Factors ◽  
Additional Control ◽  
Thin Polycrystalline ◽  
The Stability ◽  
Electron Diffractometry

A new electron diffractometer with a diffraction-pattern scanning system in front of a fixed counter has been developed. Significant improvement was achieved in the measured diffraction intensities by using fast electronics and additional control of the stability of the electron beam. The measurement of and accounting for the gear-frequency characteristic of the registration system was performed, and the signal accumulation mode for intensity measurements together with advanced statistical data processing were employed. Good agreement between the experimental and Hartree–Fock structure factors for LiF, NaF and MgO was achieved (to avoid strong extinction effects, rather thin polycrystalline films were used as samples).

STUDIES ON NUCLEOPHILIC SUBSTITUTION REACTIONS AT CARBON (SN2(C)) AND SILICON (SN2(Si)) IN TERMS OF AB INITIO, POTENTIAL, ACTING ON AN ELECTRON IN A MOLECULE AND MOLECULAR FACE THEORY

2009 ◽  
Vol 08 (supp01) ◽  
pp. 983-1001 ◽  
Author(s):  
YAN-LI DING ◽  
LI-DONG GONG ◽  
DONG-XIA ZHAO ◽  
MING-BO ZHANG ◽  
ZHONG-ZHI YANG
Keyword(s):  
Ab Initio ◽  
Nucleophilic Substitution ◽  
Gas Phase ◽  
Chemical Bond ◽  
Energy Transition ◽  
High Energy ◽  
Ab Initio Method ◽  
Substitution Reactions ◽  
Nucleophilic Substitution Reactions ◽  
High Energy Transition

The gas-phase identity bimolecular nucleophilic substitution reactions, Cl- + CH3 Cl → ClCH3 + Cl- and Cl- + SiH3Cl → ClSiH3 + Cl- , are investigated in terms of the ab initio method, potential acting on an electron in a molecule (PAEM) and molecular face (MF) theory. The computations have been performed at the CCSD(T)/aug-cc-pVTZ//MP2/6-311+G(3df,3pd) and CISD/aug-cc-pVDZ level. Based on the ab initio calculation, according to the PAEM theory, the strength of a chemical bond during forming or rupturing may be characterized by the D pb , which is a new physical quantity relating to the barrier height of the PAEM along a chemical bond. According to the MF theory, the interesting pictures of electron transfer and interpolarization effect between the reactants are clearly demonstrated to provide visualized spatial changing features of the MF for the title reactions along the IRC routes. The reason why [ Cl⋯CH3⋯Cl]- is a high-energy transition state is also analyzed in comparison with the stable low-energy intermediate [ Cl⋯SiH3⋯Cl]- .

scholarly journals Study on the Fracture Law of Inclined Hard Roof and Surrounding Rock Control of Mining Roadway in Longwall Mining Face

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5344
Author(s):  
Feng Cui ◽  
Shuai Dong ◽  
Xingping Lai ◽  
Jianqiang Chen ◽  
Chong Jia ◽  
...  
Keyword(s):  
Energy Release ◽  
Longwall Mining ◽  
Coal Pillar ◽  
High Energy ◽  
Mechanical Analysis ◽  
Engineering Practice ◽  
Analysis Model ◽  
Hard Roof ◽  
Working Face ◽  
The Stability

In the inclination direction, the fracture law of a longwall face roof is very important for roadway control. Based on the W1123 working face mining of Kuangou coal mine, the roof structure, stress and energy characteristics of W1123 were studied by using mechanical analysis, model testing and engineering practice. The results show that when the width of W1123 is less than 162 m, the roof forms a rock beam structure in the inclined direction, the floor pressure is lower, the energy and frequency of microseismic (MS) events are at a low level, and the stability of the section coal pillar is better. When the width of W1123 increases to 172 m, the roof breaks along the inclined direction, forming a double-hinged structure, the floor pressure is increased, and the frequency and energy of MS events also increases. The roof gathers elastic energy release, and combined with the MS energy release speed it can be considered that the stability of the section coal pillar is better. As the width of W1123 increases to 184 m, the roof in the inclined direction breaks again, forming a multi-hinged stress arch structure, and the floor pressure increases again. MS high-energy events occur frequently, and are not conducive to the stability of the section coal pillar. Finally, through engineering practice we verified the stability of the section coal pillar when the width of W1123 was 172 m, which provides a basis for determining the width of the working face and section coal pillar under similar conditions.

scholarly journals Photo-evaporation of close-in gas giants orbiting around G and M stars

2019 ◽  
Vol 624 ◽  
pp. A101 ◽  
Author(s):  
Daniele Locci ◽  
Cesare Cecchi-Pestellini ◽  
Giuseppina Micela
Keyword(s):  
Extreme Ultraviolet ◽  
Dynamical Evolution ◽  
High Energy ◽  
Electron Content ◽  
Mass Star ◽  
X Rays ◽  
Atmospheric Escape ◽  
Low Mass ◽  
M Stars ◽  
The Stability

Context. X-rays and extreme ultraviolet radiation impacting a gas produce a variety of effects that, depending on the electron content, may provide significant heating of the illuminated region. In a planetary atmosphere of solar composition, stellar high energy radiation can heat the gas to very high temperatures and this could affect the stability of planetary atmospheres, in particular for close-in planets. Aims. We investigate the variations with stellar age in the occurring frequency of gas giant planets orbiting G and M stars, taking into account that the high energy luminosity of a low mass star evolves in time, both in intensity and hardness. Methods. Using the energy-limited escape approach we investigated the effects induced by the atmospheric mass loss on giant exoplanet distribution that is initially flat, at several distances from the parent star. We followed the dynamical evolution of the planet atmosphere, tracking the departures from the initial profile due to the atmospheric escape, until it reaches the final mass-radius configuration. Results. We find that a significant fraction of low mass Jupiter-like planets orbiting with periods lower than ~3.5 days either vaporize during the first billion years or lose a relevant part of their atmospheres. The planetary initial mass profile is significantly distorted; in particular, the frequency of occurrence of gas giants, less massive than 2 MJ, around young stars can be considerably greater than their occurrence around older stellar counterparts.

Interactions gauches et chemins réactionnels. Etudes conformationnelles d'hydroxyalkyl-4 cyclohexènes contraints

1981 ◽  
Vol 59 (5) ◽  
pp. 859-864
Author(s):  
Jeanine Bouteiller-Prati ◽  
Jean-Claude Bouteiller ◽  
Jean-Pierre Aycard
Keyword(s):  
Free Energy ◽  
Reaction Path ◽  
High Energy ◽  
Nmr Study ◽  
Conformational Equilibria ◽  
The Stability ◽  
Cis And Trans ◽  
Conformational Free Energy

From J and δ values determined by the nmr study of alcohols obtained by addition of CH3Li and LiAlH4 to the exocyclic carbonyl of cis and trans 3-alkyl 4-carbomethoxy (or acetyl) cyclohexenes (alkyl = H, CH3, C(CH3)3), we have deduced the conformational free energy values (ΔG0X) of the CH(CH3)OH and C(CH3)2OH substituents (0.62 and 2.08 kcal mol−1 respectively) as well as the values for some related conformational equilibria. For transtert-butyl derivatives the stability of the diaxial conformer agrees with a reaction path involving high energy conformers.

A 3D passive dynamic biped with yaw and roll compensation

Robotica ◽  
2001 ◽  
Vol 19 (3) ◽  
pp. 275-284 ◽  
Author(s):  
M. Wisse ◽  
A. L. Schwab ◽  
R. Q. vd. Linde
Keyword(s):  
Degrees Of Freedom ◽  
High Energy ◽  
Roll Motion ◽  
Multibody Model ◽  
The Third ◽  
High Energy Efficiency ◽  
Dynamic Compensator ◽  
Third Dimension ◽  
The Stability ◽  
Natural Dynamics

Autonomous walking bipedal machines, possibly useful for rehabilitation and entertainment purposes, need a high energy efficiency, offered by the concept of ‘Passive Dynamic Walking' (exploitation of the natural dynamics of the robot). 2D passive dynamic bipeds have been shown to be inherently stable, but in the third dimension two problematic degrees of freedom are introduced: yaw and roll.We propose a design for a 3D biped with a pelvic body as a passive dynamic compensator, which will compensate for the undesired yaw and roll motion, and allow the rest of the robot to move as if it were a 2D machine. To test our design, we perform numerical simulations on a multibody model of the robot. With limit cycle analysis we calculate the stability of the robot when walking at its natural speed.The simulation shows that the compensator, indeed, effectively compensates for both the yaw and the roll motion, and that the walker is stable.

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