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排序方式: 共有5913条查询结果,搜索用时 31 毫秒
1.
Sørbye Sigrunn H. Nicolau Pedro G. Rue Håvard 《Statistical Inference for Stochastic Processes》2022,25(3):577-598
Statistical Inference for Stochastic Processes - The class of autoregressive (AR) processes is extensively used to model temporal dependence in observed time series. Such models are easily... 相似文献
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Simen Gjelseth Antonsen Arne Joakim C. Bunkan Tomas Mikoviny Yngve Stenstrøm Armin Wisthaler 《Molecular physics》2020,118(15)
The kinetics of the O3, OH and NO3 radical reactions with diazomethane were studied in smog chamber experiments employing long-path FTIR and PTR-ToF-MS detection. The rate coefficients were determined to be k CH2NN+O3?=?(3.2?±?0.4)?×?10?17 and k CH2NN+OH?=?(1.68?±?0.12)?×?10?10 cm3 molecule?1 s?1 at 295?±?3?K and 1013?±?30 hPa, whereas the CH2NN?+?NO3 reaction was too fast to be determined in the static smog chamber experiments. Formaldehyde was the sole product observed in all the reactions. The experimental results are supported by CCSD(T*)-F12a/aug-cc-pVTZ//M062X/aug-cc-pVTZ calculations showing the reactions to proceed exclusively via addition to the carbon atom. The atmospheric fate of diazomethane is discussed. 相似文献
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Natalie Hell Peter Beiersdorfer Gregory V. Brown Megan E. Eckart Richard L. Kelley Caroline A. Kilbourne Maurice A. Leutenegger Thomas E. Lockard F. Scott Porter Jörn Wilms 《X射线光谱测定》2020,49(1):218-233
X-ray astronomy and ground-based atomic physics have a long history of fruitful collaboration: Sound understanding of the underlying atomic physics is the key to reliable interpretation of the spectra from celestial sources; conversely, astronomical spectra have been used to benchmark and advance atomic physics. This interplay is about to become even more important as we enter a new era of high-resolution X-ray astrophysics with large effective collection area. Although high-resolution observations with the gratings on the Chandra and XMM-Newton observatories continue to drive new science, upcoming planned and proposed missions will open up new discovery space in the near future that is currently challenging to access: high-resolution spectroscopy on extended sources, in the Fe K band, and on short time scales. This review summarizes open questions in these areas and the design parameters for the Hitomi, XRISM, Athena, and Arcus observatories. The expected high quality of spectra taken with these observatories puts new constraints on the accuracy of atomic reference data required to take full advantage of the diagnostic potential of these spectra. 相似文献
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Letters in Mathematical Physics - We prove an optimal semiclassical bound on the trace norm of the following commutators $$[{\varvec{1}}_{(-\infty ,0]}(H_\hbar ),x]$$ , $$[{\varvec{1}}_{(-\infty... 相似文献
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Solvent‐Dependent Structure of the I3− Ion Derived from Photoelectron Spectroscopy and Ab Initio Molecular Dynamics Simulations 下载免费PDF全文
Dr. Naresh K. Jena Ida Josefsson Dr. Susanna K. Eriksson Prof. Anders Hagfeldt Prof. Hans Siegbahn Prof. Olle Björneholm Prof. Håkan Rensmo Dr. Michael Odelius 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(10):4049-4055
Ab initio molecular dynamics (MD) simulations of the solvation of LiI3 in four different solvents (water, methanol, ethanol, and acetonitrile) are employed to investigate the molecular and electronic structure of the I3? ion in relation to X‐ray photoelectron spectroscopy (XPS). Simulations show that hydrogen‐bond rearrangement in the solvation shell is coupled to intramolecular bond‐length asymmetry in the I3? ion. By a combination of charge analysis and I 4 d core‐level XPS measurements, the mechanism of the solvent‐induced distortions has been studied, and it has been concluded that charge localization mediates intermolecular interactions and intramolecular distortion. The approach involving a synergistic combination of theory and experiment probes the solvent‐dependent structure of the I3? ion, and the geometric structure has been correlated with the electronic structure. 相似文献
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Fourier transform infrared (FTIR) smog chamber techniques were used to investigate the atmospheric chemistry of the isotopologues of methane. Relative rate measurements were performed to determine the kinetics of the reaction of the isotopologues of methane with OH radicals in cm3 molecule−1 s−1 units: k(CH3D + OH) = (5.19 ± 0.90) × 10−15, k(CH2D2 + OH) = (4.11 ± 0.74) × 10−15, k(CHD3 + OH) = (2.14 ± 0.43) × 10−15, and k(CD4 + OH) = (1.17 ± 0.19) × 10−15 in 700 Torr of air diluent at 296 ± 2 K. Using the determined OH rate coefficients, the atmospheric lifetimes for CH4–xDx (x = 1–4) were estimated to be 6.1, 7.7, 14.8, and 27.0 years, respectively. The results are discussed in relation to previous measurements of these rate coefficients. 相似文献
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