scholarly journals The EI‐MS fragmentation mechanisms of the bacterial diterpenes polytrichastrene A and wanju‐2,5‐diene

2021 ◽  
Author(s):  
Anwei Hou ◽  
Jeroen S. Dickschat
Keyword(s):  
Fragmentation Mechanisms

scholarly journals Difference in polypropylene fragmentation mechanism between marine and terrestrial regions

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Hisayuki Nakatani ◽  
Takuya Muraoka ◽  
Yuina Ohshima ◽  
Suguru Motokucho
Keyword(s):  
Environmental Stress ◽  
Advanced Oxidation Process ◽  
List Type ◽  
Patch Structure ◽  
Stress Cracking ◽  
Fragmentation Mechanisms ◽  
Environmental Stress Cracking ◽  
Speed Up ◽  
Degradation Time ◽  
Delamination Behavior

AbstractTwo kinds of marine polypropylene (M1-PP and M2-PP) and one land PP (L-PP) samples were collected from two beaches and land in Japan, respectively, to study the fragmentation mechanisms. Delamination was observed on both M1-PP and M2-PP surfaces. Moreover, there was no delamination but an abrasion patch structure on the surface of L-PP. The delamination was studied using an advanced oxidation process-degraded PP as the marine PP model. The number and shape of cracks varied with an increase in degradation time. The fluctuations in the values and ratios of the carbonyl index as well as the weight change ratio were due to repeated oxidation and delamination. We found that the delamination behavior depends on the oxidation state. Poly(oxyethylene)8 octylphenyl ether (POE8) surfactant treatment caused the delamination to speed up, which is a typical characteristic of polyolefin environmental stress cracking (ESC). These results reveal that delamination is based on ESC.Article Highlights Two kinds of marine and one land polypropylene (PP) samples were collected from two beaches and land, respectively, to study the fragmentation mechanisms. Delamination was observed on both of marine PP surfaces. Moreover, there was no delamination but an abrasion patch structure on the land PP surface. We found that the delamination was based on environmental stress cracking mechanism by employing a marine PP model.

scholarly journals Mass spectral and theoretical investigations of the transient proton-bound dimers on the cleavage processes of the peptide GHK and its analogues

RSC Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 4077-4086
Author(s):  
Jinhu Wang ◽  
Cheng Wang ◽  
Han Zhang ◽  
Yang Liu ◽  
Tiesheng Shi
Keyword(s):  
Mass Spectrometry ◽  
Theoretical Calculations ◽  
Mass Spectral ◽  
Protonated Peptides ◽  
Fragmentation Mechanisms ◽  
Theoretical Investigations

Fragmentation mechanisms of the singly protonated peptides GHK, GHKH and HGHK have been investigated by mass spectrometry and theoretical calculations.

Graph theory-based reaction pathway searches and DFT calculations for the mechanism studies of free radical-initiated peptide sequencing mass spectrometry (FRIPS MS): a model gas-phase reaction of GGR tri-peptide

2020 ◽  
Vol 22 (9) ◽  
pp. 5057-5069 ◽  
Author(s):  
Jae-ung Lee ◽  
Yeonjoon Kim ◽  
Woo Youn Kim ◽  
Han Bin Oh
Keyword(s):  
Graph Theory ◽  
Dft Calculations ◽  
Gas Phase ◽  
Density Functional ◽  
Reaction Pathway ◽  
Peptide Sequencing ◽  
Phase Reaction ◽  
Functional Theory ◽  
Fragmentation Mechanisms ◽  
Gas Phase Fragmentation

A new approach for elucidating gas-phase fragmentation mechanisms is proposed: graph theory-based reaction pathway searches (ACE-Reaction program) and density functional theory (DFT) calculations.

Monte Carlo studies on electromagnetic cascades in extensive air showers

1968 ◽  
Vol 46 (10) ◽  
pp. S189-S196 ◽  
Author(s):  
K. O. Thielheim ◽  
E. K. Schlegel ◽  
R. Beiersdorf
Keyword(s):  
Monte Carlo ◽  
Electron Density ◽  
Three Dimensional ◽  
High Energy ◽  
Extensive Air Showers ◽  
Air Showers ◽  
Energy Distributions ◽  
The Core ◽  
Fragmentation Mechanisms ◽  
Monte Carlo Studies

Three-dimensional Monte Carlo calculations have been performed on the trajectories of high-energy hadrons in extensive air showers. The central electron density and gradient of distribution are obtained for individual electromagnetic cascades together with coordinates at the level of observation. Various assumptions concerning primary mass number and energy, distributions of strong interaction parameters, and fragmentation mechanisms are discussed with respect to the production of steep maxima of electron density by single electromagnetic cascades in the core region of extensive air showers.

Texture discrimination of volcanic ashes from different fragmentation mechanisms: A case study, Mount Nemrut stratovolcano, eastern Turkey

2006 ◽  
Vol 32 (7) ◽  
pp. 936-946 ◽  
Author(s):  
Orkun Ersoy ◽  
Gary Chinga ◽  
Erkan Aydar ◽  
Alain Gourgaud ◽  
H. Evren Cubukcu ◽  
...  
Keyword(s):  
Texture Discrimination ◽  
Eastern Turkey ◽  
Fragmentation Mechanisms ◽  
Volcanic Ashes
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