scholarly journals Computational study on the mechanism and kinetics for the reaction between HO2 and n-propyl peroxy radical

RSC Advances ◽  
2019 ◽  
Vol 9 (69) ◽  
pp. 40437-40444
Author(s):  
Zhenli Yang ◽  
Xiaoxiao Lin ◽  
Jiacheng Zhou ◽  
Mingfeng Hu ◽  
Yanbo Gai ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Temperature Regime ◽  
Computational Study ◽  
Peroxy Radical ◽  
Negative Temperature ◽  
Mechanism And Kinetics ◽  
Lower Temperature

The negative temperature dependence for the HO2 + n-C3H7O2 reaction in lower temperature regime.

Ammonothermal growth of GaN utilizing negative temperature dependence of solubility in basic ammonia

2004 ◽  
Vol 831 ◽  
Author(s):  
Tadao Hashimoto ◽  
Kenji Fujito ◽  
Feng Wu ◽  
Benjamin A. Haskell ◽  
Paul T. Fini ◽  
...  
Keyword(s):  
Weight Loss ◽  
Temperature Dependence ◽  
Fluid Transport ◽  
Defect Density ◽  
Negative Temperature ◽  
Solubility Limit ◽  
Temperature Zone ◽  
Free Standing ◽  
Lower Temperature ◽  
Ammonothermal Growth

ABSTRACTAmmonothermal growth of GaN was studied to determine its eventual utility for mass production of GaN bulk crystals. Dissolution of GaN in supercritical ammonia with 1 M NaNH2 was investigated through a weight loss method. The time dependence of the weight loss was examined at 500°C and 525°C. Since the weight loss did not reach saturation as a function of time, the solubility limit was not realized. However, experiments demonstrate that GaN has a negative temperature dependence of solubility in supercritical ammonobasic solutions. Based on this result, GaN was grown via fluid transport from metallic Ga to a free-standing GaN single crystal seed by placing the seed crystal in a higher temperature zone and the nutrient in a lower temperature zone. GaN films with thickness of 5 μm (Ga face) and 4 μm (N face) were simultaneously grown on the seed in three days. The surface morphology, optical property, and defect density were found to be different for films on Ga face and N face.

scholarly journals Experimental and Computational Study of a Liquid Crystalline Dimesogen Exhibiting Nematic, Twist-Bend Nematic, Intercalated Smectic, and Soft Crystalline Mesophases

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 532
Author(s):  
Emily E. Pocock ◽  
Richard J. Mandle ◽  
John W. Goodby
Keyword(s):  
Liquid Crystalline ◽  
Computational Study ◽  
Structure Property ◽  
Correlation Lengths ◽  
Aspect Ratios ◽  
Smectic Phases ◽  
Out Of Plane ◽  
Lower Temperature ◽  
Soft Crystal ◽  
Optical Textures

Liquid crystalline dimers and dimesogens have attracted significant attention due to their tendency to exhibit twist-bend modulated nematic (NTB) phases. While the features that give rise to NTB phase formation are now somewhat understood, a comparable structure–property relationship governing the formation of layered (smectic) phases from the NTB phase is absent. In this present work, we find that by selecting mesogenic units with differing polarities and aspect ratios and selecting an appropriately bent central spacer we obtain a material that exhibits both NTB and intercalated smectic phases. The higher temperature smectic phase is assigned as SmCA based on its optical textures and X-ray scattering patterns. A detailed study of the lower temperature smectic ‘’X’’ phase by optical microscopy and SAXS/WAXS demonstrates this phase to be smectic, with an in-plane orthorhombic or monoclinic packing and long (>100 nm) out of plane correlation lengths. This phase, which has been observed in a handful of materials to date, is a soft-crystal phase with an anticlinic layer organisation. We suggest that mismatching the polarities, conjugation and aspect ratios of mesogenic units is a useful method for generating smectic forming dimesogens.

Negative Temperature-Dependence of Stress-Induced R→B19′ Transformation in Nanocrystalline NiTi Alloy

2021 ◽  
Author(s):  
Taotao Wang ◽  
Xiangxiang Rao ◽  
Daqiang Jiang ◽  
Yang Ren ◽  
Lishan Cui ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Niti Alloy ◽  
Negative Temperature

Computational Study on the Existence of Organic Peroxy Radical-Water Complexes (RO2·H2O)

2008 ◽  
Vol 112 (7) ◽  
pp. 1587-1595 ◽  
Author(s):  
Jared Clark ◽  
Alecia M. English ◽  
Jaron C. Hansen ◽  
Joseph S. Francisco
Keyword(s):  
Computational Study ◽  
Peroxy Radical

Mineral partitioning in milk and milk permeates at high temperature

2011 ◽  
Vol 79 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Divina D Kaombe ◽  
Yanhong Du ◽  
Michael J Lewis
Keyword(s):  
High Temperature ◽  
Calcium Phosphate ◽  
Temperature Dependence ◽  
Casein Micelle ◽  
Soluble Phase ◽  
Ionic Calcium ◽  
Separation Temperature ◽  
Two Temperatures ◽  
Lower Temperature ◽  
Mineral Partitioning

The soluble phase of milk was separated at 20 and 80°C using ultrafiltration. The resulting permeates were then subjected to further ultrafiltration and dialysis at close to these two temperatures. It was found that pH, Ca2+ and soluble Ca decreased as the separation temperature increased both in original UF permeates and in dialysates obtained from these permeates, but P decreased only slightly. The major reason for these changes was due to the precipitation of calcium phosphate/citrate complexes onto the casein micelle with concomitant release of H+. The pH of both permeates and dialysates from milk at 20°C were slightly higher than for milk. When UF permeates collected at 20 and 80°C, were each dialysed at both these temperatures, the dialysate collected at 80°C showed much less temperature dependence for pH and ionic calcium compared with that collected at 20°C. This is in contrast to milk, which shows considerable temperature dependence for pH and ionic calcium. Further experiments revealed that the pH and Ca2+ concentration of permeates showed high temperature dependence above the temperature at which they were separated, but a much lower temperature dependence below that temperature. These findings suggest that dialysis and UF of milk at high temperature provide the best means yet for estimating the pH and ionic calcium of milk at that temperature.

MECHANISM AND KINETICS OF THE CH3CH2C(O)OCH2CH3 + OH REACTION: A THEORETICAL STUDY

2011 ◽  
Vol 10 (05) ◽  
pp. 691-709 ◽  
Author(s):  
CONG HOU ◽  
CHENG-GANG CI ◽  
TONG-YIN JIN ◽  
YONG-XIA WANG ◽  
JING-YAO LIUM
Keyword(s):  
Rate Constants ◽  
Hydrogen Abstraction ◽  
Negative Temperature ◽  
State Theory ◽  
Measured Temperature ◽  
Temperature Range ◽  
Global Rate ◽  
Abstraction Reaction ◽  
Lower Temperature ◽  
Kinetic Calculations

The hydrogen abstraction reaction of CH 3 CH 2 C(O)OCH 2 CH 3 + OH has been studied theoretically by dual-level direct dynamics method. Six H-abstraction channels were found for this reaction. The required potential energy surface information for the kinetic calculations was obtained at the MCG3-MPWB//M06-2X/aug-cc-pVDZ level. The rate constants were calculated by the improved canonical variational transition-state theory with small-curvature tunneling correction (ICVT/SCT) approach in the temperature range of 200–2000 K. It is shown that the "methylene H-abstraction" from the alkoxy end of the ester CH 3 CH 2 C(O)OCH 2 CH 3 is the dominant channel at lower temperature (< 400 K), while the other channels from the acetyl end should be taken into account as the temperature increases and become the competitive ones at higher temperature. The calculated global rate constants are in good agreement with the experimental ones in the measured temperature range and exhibit a negative temperature dependence below 500 K. A four-parameter rate constant expression was fitted from the calculated kinetic data between 200–2000 K.

scholarly journals Reversible and repeatable phase transition at a negative temperature regime for doped and co-doped spin coated mixed valence vanadium oxide thin films

RSC Advances ◽  
2018 ◽  
Vol 8 (54) ◽  
pp. 30966-30977 ◽  
Author(s):  
Dipta Mukherjee ◽  
Arjun Dey ◽  
A. Carmel Mary Esther ◽  
N. Sridhara ◽  
D. Raghavendra Kumar ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Vanadium Oxide ◽  
Temperature Regime ◽  
Spin Coating ◽  
Mixed Valence ◽  
Negative Temperature ◽  
Coating Technique ◽  
Vanadium Oxide Thin Films ◽  
Co Doped

Smooth, uniform mixed valance vanadium oxide (VO) thin films are grown on flexible, transparent Kapton and opaque Al6061 substrates by the spin coating technique at a constant rpm of 3000.

Sign in / Sign up

Export Citation Format

Share Document