scholarly journals Theoretical study on the thermal dissociation of FOX-7 promoted by NO2

2021 ◽  
Author(s):  
Shuhui Yin ◽  
Qiong Zhu ◽  
Jianyong Liu ◽  
Panwang Zhou
Keyword(s):  
Reaction Mechanism ◽  
Hot Spots ◽  
Quantum Chemical ◽  
High Performance ◽  
Catalytic Effect ◽  
Theoretical Study ◽  
Energetic Material ◽  
Thermal Dissociation ◽  
Bimolecular Reaction ◽  
Low Sensitivity

1,1-diamino-2,2-dinitroethene (FOX-7) is a novel energetic material with high performance and low sensitivity. In order to deeply understand the reaction mechanism in the initiation “hot spots” of FOX-7 and reveal the growth mechanism of these initiation “hot spots” in the explosion process, the detailed mechanisms of bimolecular reaction of NO2 and FOX-7, as well as the subsequent reactions have been investigated by the quantum chemical calculations. The mechanism of NO2 and FOX-7 bimolecular reaction and the catalytic effect of NO2 were revealed by three key dissociation paths. It is demonstrated that the NO2 molecule plays an important role in promoting the decomposition of the FOX-7 molecule, and the main exothermic pathways were the reactions between oxidizing intermediates (NO, NO2), and reducing intermediates (CO, NH3).

scholarly journals Theoretical study on the reaction mechanism of the thermal cis–trans isomerization of fluorine-substituted azobenzene derivatives

RSC Advances ◽  
2018 ◽  
Vol 8 (21) ◽  
pp. 11580-11588 ◽  
Author(s):  
Xiao-Mei Liu ◽  
Xing-Yi Jin ◽  
Zhi-Xiang Zhang ◽  
Jian Wang ◽  
Fu-Quan Bai
Keyword(s):  
Reaction Mechanism ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Theoretical Study ◽  
Thermal Isomerization ◽  
Trans Isomerization ◽  
Azobenzene Derivatives

Quantum chemical calculations of a set of valid photoswitches of azobenzene compounds, with the aim of describing their thermal isomerization.

Theoretical study on the reaction mechanism of OH radical with Z(E)-CF3CHCHF

2019 ◽  
Vol 21 (3) ◽  
pp. 1367-1374 ◽  
Author(s):  
Chao Xu ◽  
Chaoyang Wang ◽  
Bo Li ◽  
Linping Hu ◽  
Feng Long Gu
Keyword(s):  
Reaction Mechanism ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Theoretical Study ◽  
Oh Radicals ◽  
Oh Radical ◽  
Transformation Mechanism ◽  
Mechanism And Kinetics ◽  
Kinetics Of

The comprehensive transformation mechanism and kinetics of Z(E)-CF3CHCHF initiated by OH radicals were investigated by performing quantum chemical calculations.

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Theoretical study of the ketonization reaction mechanism of acetic acid over SiO2

2009 ◽  
Author(s):  
Mendel Fleisher ◽  
E. Lukevics ◽  
L. Leite ◽  
D. Jansone ◽  
K. Edolfa ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Theoretical Study

EFFECT OF ZINC DITHIOCARBAMATES AND THIAZOLE-BASED ACCELERATORS ON THE VULCANIZATION OF NATURAL RUBBER

2012 ◽  
Vol 85 (1) ◽  
pp. 120-131 ◽  
Author(s):  
Md. Najib Alam ◽  
Swapan Kumar Mandal ◽  
Subhas Chandra Debnath
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
High Performance ◽  
Binary Systems ◽  
Synergistic Activity ◽  
Tetramethylthiuram Disulfide

Abstract Several zinc dithiocarbamates (ZDCs) as accelerator derived from safe amine has been exclusively studied in the presence of thiazole-based accelerators to introduce safe dithiocarbamate in the vulcanization of natural rubber. Comparison has been made between conventional unsafe zinc dimethyldithiocarbamate (ZDMC) with safe novel ZDC combined with thizole-based accelerators in the light of mechanical properties. The study reveals that thiuram disulfide and 2-mercaptobenzothiazole (MBT) are always formed from the reaction either between ZDC and dibenzothiazyledisulfide (MBTS) or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that MBT generated from MBTS or CBS reacts with ZDC and produces tetramethylthiuram disulfide. The observed synergistic activity has been discussed based on the cure and physical data and explained through the results based on high-performance liquid chromatography and a reaction mechanism. Synergistic activity is observed in all binary systems studied. The highest tensile strength is observed in the zinc (N-benzyl piperazino) dithiocarbamate-accelerated system at 3:6 mM ratios. In respect of tensile strength and modulus value, unsafe ZDMC can be successfully replaced by safe ZDCs in combination with thiazole group containing accelerator.

scholarly journals Prebiotic Route to Thymine from Formamide—A Combined Experimental–Theoretical Study

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2248
Author(s):  
Lukáš Petera ◽  
Klaudia Mrazikova ◽  
Lukas Nejdl ◽  
Kristyna Zemankova ◽  
Marketa Vaculovicova ◽  
...  
Keyword(s):  
Formic Acid ◽  
Quantum Chemical ◽  
Prebiotic Chemistry ◽  
Theoretical Study ◽  
Reaction Pathway ◽  
Hydrolysis Product ◽  
Current Paper ◽  
Reaction Conditions ◽  
Chemical Modeling ◽  
Chemistry Research

Synthesis of RNA nucleobases from formamide is one of the recurring topics of prebiotic chemistry research. Earlier reports suggest that thymine, the substitute for uracil in DNA, may also be synthesized from formamide in the presence of catalysts enabling conversion of formamide to formaldehyde. In the current paper, we show that to a lesser extent conversion of uracil to thymine may occur even in the absence of catalysts. This is enabled by the presence of formic acid in the reaction mixture that forms as the hydrolysis product of formamide. Under the reaction conditions of our study, the disproportionation of formic acid may produce formaldehyde that hydroxymethylates uracil in the first step of the conversion process. The experiments are supplemented by quantum chemical modeling of the reaction pathway, supporting the plausibility of the mechanism suggested by Saladino and coworkers.

scholarly journals Plasmonic semiconductor nanogroove array enhanced broad spectral band millimetre and terahertz wave detection

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jinchao Tong ◽  
Fei Suo ◽  
Tianning Zhang ◽  
Zhiming Huang ◽  
Junhao Chu ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
High Performance ◽  
Room Temperature ◽  
Spectral Band ◽  
High Capacity ◽  
Terahertz Wave ◽  
Semiconductor Surface ◽  
Wide Range ◽  
Low Sensitivity ◽  
Air Interfaces

AbstractHigh-performance uncooled millimetre and terahertz wave detectors are required as a building block for a wide range of applications. The state-of-the-art technologies, however, are plagued by low sensitivity, narrow spectral bandwidth, and complicated architecture. Here, we report semiconductor surface plasmon enhanced high-performance broadband millimetre and terahertz wave detectors which are based on nanogroove InSb array epitaxially grown on GaAs substrate for room temperature operation. By making a nanogroove array in the grown InSb layer, strong millimetre and terahertz wave surface plasmon polaritons can be generated at the InSb–air interfaces, which results in significant improvement in detecting performance. A noise equivalent power (NEP) of 2.2 × 10−14 W Hz−1/2 or a detectivity (D*) of 2.7 × 1012 cm Hz1/2 W−1 at 1.75 mm (0.171 THz) is achieved at room temperature. By lowering the temperature to the thermoelectric cooling available 200 K, the corresponding NEP and D* of the nanogroove device can be improved to 3.8 × 10−15 W Hz−1/2 and 1.6 × 1013 cm Hz1/2 W−1, respectively. In addition, such a single device can perform broad spectral band detection from 0.9 mm (0.330 THz) to 9.4 mm (0.032 THz). Fast responses of 3.5 µs and 780 ns are achieved at room temperature and 200 K, respectively. Such high-performance millimetre and terahertz wave photodetectors are useful for wide applications such as high capacity communications, walk-through security, biological diagnosis, spectroscopy, and remote sensing. In addition, the integration of plasmonic semiconductor nanostructures paves a way for realizing high performance and multifunctional long-wavelength optoelectrical devices.

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