A three dimensional solution of the steady state diffusion equation, with boundary conditions applicable to closed can 222Rn exhalation measurements is described. A modified one-dimensional formalism is introduced which allows the interpretation of the results from exhalation measurements in terms of one-dimensional 222Rn exhalation from walls.
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http://dx.doi.org/10.1097/00004032-198811000-00009 | DOI Listing |
Acc Chem Res
January 2025
Laboratory for Chemistry and Life Science (CLS), Institute of Integrated Research, Institute of Science Tokyo, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
ConspectusThe design of properties and functions of molecular assemblies requires not only a proper choice of building blocks but also control over their packing arrangements. A highly versatile unit in this context is a particular type of triptycene with substituents at the 1,8,13-positions, called tripodal triptycene, which offers predictable molecular packing and multiple functionalization sites, both at the opposite 4,5,16- or 10 (bridgehead)-positions. These triptycene building blocks are capable of two-dimensional (2D) nested hexagonal packing, leading to the formation of 2D sheets, which undergo one-dimensional (1D) stacking into well-defined "2D+1D" structures.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
Department of Agricultural Technology, Center for Precision Agriculture, Norwegian Institute of Bioeconomy Research (NIBIO), Nylinna 226 2849, Kapp, Norway.
Raman spectroscopy is a powerful and non-invasive analytical method for determining the chemical composition and molecular structure of a wide range of materials, including complex biological tissues. However, the captured signals typically suffer from interferences manifested as noise and baseline, which need to be removed for successful data analysis. Effective baseline correction is critical in quantitative analysis, as it may impact peak signature derivation.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Deep Space Exploration Laboratory/Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, People's Republic of China.
This paper performed a comprehensive study of the thermal nonequilibrium effects of CO/Ar mixtures with various degrees of N2 additions and probed the N2 relaxation behaviors via the CO rovibrational thermometry. The rovibrational temperature time histories of shock-heated CO/N2/Ar mixtures were measured via a laser-absorption technique, and the corresponding vibrational relaxation data were summarized at 1890-3490 K. The measured results were compared with predictions from the Schwartz-Slawsky-Herzfeld (SSH) formula and the state-to-state (StS) approach (treating CO and N2 as pseudo-species).
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Key Laboratory of Bio-Based Polymeric Materials of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China.
Solid acid catalysts have attracted much attention in cellulose hydrolysis due to their high product selectivity, easy preparation and reusability. However, most current researches only focus on modifying their surface functional groups but overlook the impact of carrier shape on hydrolytic performance. Herein, we synthesize a series of rod-shaped silica with varying sizes for cellulose hydrolysis to analyze the shape mode to enhance the breaking of cellulose structure during solid-solid reaction.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
School of Chemistry, Beihang University, Beijing, 100191, China.
Controlled synthesis of one-dimensional materials at atomic-scale dimensions represents a milestone in nanotechnology, offering the potential to maximize atom utilization while enhancing catalytic performance. However, achieving structural stability and durability at such fine scales requires precise control over material structure and local chemical environment. Here, we introduce dimethylamine (DMA) as a small-molecule modifier, in contrast to conventional long-chain surfactants, to interact with surface Pt atoms.
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