The formation of C(x)F(2x+1)CH2C(O)OONO2 (x = 1,6) from the photooxidation of C(x)F(2x+1)CH2C(O)H (x = 1,6) in the presence of NO2 was investigated. The infrared spectrum of C6F13CH2C(O)OONO2 is reported for the first time, and thermal stability for both peroxynitrates at 295 K and 9.0 mbar is informed. Kinetic parameters (activation energy and pre-exponential factor) for CF3CH2C(O)OONO2 at 9.0 and 1000 mbar are: 108 ± 2 kJ/mol, 1.5 × 10(15) and 114 ± 2 kJ/mol, 2.4 × 10(16), respectively. A comparison is made between fluoro and hydrogenated peroxy acyl nitrates.
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http://dx.doi.org/10.1021/jp4003593 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
School of Mechanics and Aerospace Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
Ceramic aerogels are promising high-temperature thermal insulation materials due to their outstanding thermal stability and oxidation resistance. However, restricted by nanoparticle-assembled network structures, conventional ceramic aerogels commonly suffer from inherent brittleness, volume shrinkage, and structural collapse at high temperatures. Here, to overcome such obstacles, 3D ultralight and highly porous carbon tube foams (CTFs) were designed and synthesized as the carbonaceous precursors, where melamine foams were used as the sacrificial templates to form the hollow and thin-wall network structures in the CTFs (density: ∼4.
View Article and Find Full Text PDFRev Sci Instrum
January 2025
OzGrav-ANU, ARC Centre for Gravitational Astrophysics, College of Science, The Australian National University, Canberra ACT2601, Australia.
We present the design and commissioning of a cryogenic low-vibration test facility that measures displacement noise from a gram-scale silicon cantilever at the level of 10-16m/Hz at 1 kHz. This sensitivity is necessary for future tests of thermal noise models on cross sections of silicon suspension samples proposed for future gravitational-wave detectors. A volume of ∼36 l is enclosed by radiation shields cooling an optical test cavity that is suspended from a multi-stage pendulum chain providing isolation from acoustic and environmental noise.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011.
From molecular dynamics (MD) simulations of melt-quenching and thermal aging procedures in pure Ag, Cu, Ag-Cu binary alloys, and Cu-Zr binary alloys, we have identified two distinct amorphous phases for a metastable undercooled liquid: the homogeneous L-phase with low shear rigidity and the heterogenous G-phase with much higher shear rigidity and a heterogeneity length scale Λ. Here, we examine two-phase equilibration studies showing that the G-phase melts to form the L-phase above ~1,000 K, which then transforms to form the crystal (X) phase; however, below the melting point of the G-Phase (~990 K), the X- and G-phases do not transform into each other. We suggest the presence of a G-phase is likely responsible for embrittlement often observed in metallic glasses.
View Article and Find Full Text PDFComput Methods Biomech Biomed Engin
January 2025
Department of Clinical Surgery, Cty Clin Emergency Hosp, Sibiu, Romania.
This study examines heat transfer and nanofluid-enhanced blood flow behaviour in stenotic arteries under inflammatory conditions, addressing critical challenges in cardiovascular health. The blood, treated as a Newtonian fluid, is augmented with gold nanoparticles to improve thermal conductivity and support drug delivery applications. A hybrid methodology combining finite element method (FEM) for numerical modelling and artificial neural networks (ANN) for stability prediction provides a robust analytical framework.
View Article and Find Full Text PDFJ Chem Inf Model
January 2025
Molecular Modeling Section (MMS), Department of Pharmaceutical and Pharmacological Sciences, University of Padova, via Marzolo 5, Padova 35131, Italy.
During the last 20 years, the fragment-based drug discovery approach gained popularity in both industrial and academic settings due to its efficient exploration of the chemical space. This bottom-up approach relies on identifying high-efficiency small ligands (fragments) that bind to a target binding site and then rationally evolve them into mature druglike compounds. To achieve such a task, researchers rely on accurate information about the ligand binding mode, usually obtained through experimental techniques, such as X-ray crystallography or computer simulations.
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