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排序方式: 共有155条查询结果,搜索用时 515 毫秒
1.
Ozonolysis of a Series of Methylated Alkenes: Reaction Rate Coefficients and Gas‐Phase Products 下载免费PDF全文
Tristan Braure Véronique Riffault Alexandre Tomas Romeo Iulian Olariu Cecilia Arsene Yuri Bedjanian Patrice Coddeville 《国际化学动力学杂志》2015,47(9):596-605
The gas‐phase ozonolysis of three methylated alkenes, i.e., trans‐2,2‐dimethyl‐3‐hexene (22dM3H), trans‐2,5‐dimethyl‐3‐hexene (25dM3H), and 4‐methyl‐1‐pentene (4M1P), has been investigated in the presence of sufficient hydroxyl radical scavenger in a laminar flow reactor at ambient temperature (296 ± 2 K) and P = 1 atm of dry air (RH ≤ 5%). Ozone levels in the reactor were monitored by an automatic analyzer. Alkene and gas‐phase product concentrations were determined via online sampling either on three‐bed adsorbent cartridges followed by thermodesorption and GC/FID‐MS analysis or on 2,4‐dinitrophenylhydrazine (DNPH) cartridges for subsequent HPLC/UV analysis. Reaction rate coefficients of (3.38 ± 0.12) × 10?17 for 22dM3H and (2.71 ± 0.26) × 10?17 for 25dM3H, both in cm3 molecule?1 s?1 units, have been obtained under pseudo–first‐order conditions. Primary carbonyl products have been identified for the three investigated alkenes, and branching ratios are reported. In the case of 4M1P ozonolysis, the yield of a Criegee intermediate was indirectly determined. Kinetics and product study results are compared to those of literature when available. This work represents the first investigation of reaction products in the ozonolysis of 22dM3H, 25dM3H, and 4M1P in a flow reactor. 相似文献
2.
We report on various integration schemes of infrared microbolometers with microstrip antennas. The first integration design consists of two gold (Au) rectangular microstrip patches coupled along the radiating edges by a narrow niobium (Nb) strip. Devices using silicon oxide are compared to devices using amorphous silicon as antenna substrate. An extension of the twin-patch detector design is the microstrip dipole antenna-coupled microbolometer. Two ways of connecting the device to the contact pads via narrow dc leads are presented and compared. The contribution of the dc leads to the detector response is eliminated by directly connecting the dipole to the contact pads. The thermal isolation of the microbolometer from the silicon wafer is improved by incorporating air into the antenna dielectric substrate. This leads to higher detector responsivity and shifts the resonance towards longer antennas. The implementation of a bridge microstrip dipole antenna structure is also discussed. 相似文献
3.
4.
Calin Iulian Martin 《Journal of Nonlinear Mathematical Physics》2015,22(4):516-522
This paper is devoted to the subsurface current dynamics in equatorial regions, where the hallmark of a strong stratification is a sharp interface (thermocline), separating two layers of different density, and whose depth is dependent upon the strength of the winds above the ocean's surface. We give here a few monotonicity results concerning the dynamics of the thermocline in the equatorial region. The most important one asserts that the level of the thermocline decreases as the strength of the wind at ten meters above the ocean surface, denoted |Uw|, increases. Moreover, the strength of the current at the thermocline decreases as |Uw| increases. 相似文献
5.
A method for estimating the distribution of scan statistics with high precisìon was introduced in Haiman (2000). Using that method sharp bounds for the errors were also established. This paper is concerned with the application of the method in Haiman (2000) to a two-dimensional Poisson process. The method involves the estimation by simulation of the conditional (fixed number of points) distribution of scan statistics for the particular rectangle sets of size 2 × 2, 2 × 3, 3 × 3, where the unit is the (1 × 1) dimension of the squared scanning window. In order to perform these particular estimations, we develop and test a perfect simulation algorithm. We then perform several numerical applications and compare our results with results obtained by other authors. 相似文献
6.
G. Benzoni F. Azaiez S. Leoni S. Battacharyya R. Borcea A. Bracco L. Corradi D. Curien G. De France Zs. Dombrádi E. Fioretto S. Franchoo S. Grevy F. Ibrahim S. Iulian G. Mukherjee A. Navin G. Pollarolo N. Redon P. H. Regan M. Rejmund C. Schmitt G. Sletten D. Sohler M. Stanoiu S. Szilner D. Verney 《The European physical journal. Special topics》2007,150(1):83-86
A study of deep-inelastic and multi-nucleon transfer reactions to populate neutron-rich
O, Ne and F nuclei is here presented. The reaction under analysis employed a beam of radioactive
24Ne at 7.9 AMeV, provided by the
SPIRAL facility at Ganil, impingin on a 208Pb target. The reaction products have been
detected in the VAMOS spectrometer in coincidence with gamma rays
measured by the EXOGAM array. Preliminary results here presented show a selectivity
in the population of states of different nature. 相似文献
7.
Core-level electronic properties of nanostructured NiO coatings 总被引:1,自引:0,他引:1
Nanostructured NiO films with different thicknesses were grown on nanoporous alumina membrane substrates by reactive evaporation of Ni in an oxygen atmosphere. The reactive deposition process was assisted by a low energy oxygen ion-beam in order to increase the NiO input into the pores. Surface morphology and structure of the films were analyzed by SEM and XPS. SEM observations reveal a well adhered film of NiO on the substrate. This film appears to be uniform and presents a rather irregular nanostructured morphology, built of NiO clusters with sizes ranging between 5 and 30 nm. The core-level electronic properties of this nanostructured NiO film result to be similar to those of an ultrathin film about one monolayer thick. This behaviour can be explained by the large surface to volume ratio of both systems. 相似文献
8.
Hans J. Breunig Tim Koehne Ana Maria Preda Cristian Silvestru Luis F. Piedra-Garza 《Journal of organometallic chemistry》2010,695(9):1307-1313
The syntheses and spectroscopic (NMR, MS) investigations of the antimonates [Ph4P]+[Me2SbCl4]− (1), [Me4Sb]+[Me2SbCl4]− (2), [Et4N]+[Ph2SbCl4]− (3), [Bu4N]+[Ph2SbCl4]− (4), [Me4Sb]+[Ph2SbCl4]− (5), [Et3MeSb]+[Ph2SbCl4]− (6), [Et4N]+[Ph2SbF4]− (7) and [Et4N]+[Ph2SbBr4]− (8) are reported. Halogen scrambling reactions of Et4NBr or Ph4EBr (E = P, Sb) with R2SbCl3 (R = Me, Ph) produce mixtures of compounds from which crystals of [Et4N]+[Ph2SbBr1.24Cl2.76]− (9), [Et4N]+[Ph2SbBr2.92Cl1.08]− (10) or [Ph4Sb]+[Me2SbCl4]− (11) were isolated. The crystal and molecular structures of 1 and 3-11 are reported. 相似文献
9.
Francesco Napoli Dr. Mario Chiesa Dr. Elio Giamello Prof. Gloria Preda Dr. Cristiana Di Valentin Dr. Gianfranco Pacchioni Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(23):6776-6785
The formation of O2? radical anions by contact of O2 molecules with a Na pre‐covered MgO surface is studied by a combined EPR and quantum chemical approach. Na atoms deposited on polycrystalline MgO samples are brought into contact with O2. The typical EPR signal of isolated Na atoms disappears when the reaction with O2 takes place and new paramagnetic species are observed, which are attributed to different surface‐stabilised O2? radicals. Hyperfine sublevel correlation (HYSCORE) spectroscopy allows the superhyperfine interaction tensor of O2?Na+ species to be determined, demonstrating the direct coordination of the O2? adsorbate to surface Na+ cations. DFT calculations enable the structural details of the formed species to be determined. Matrix‐isolated alkali superoxides are used as a standard to enable comparison of the formed species, revealing important and unexpected contributions of the MgO matrix in determining the electronic structure of the surface‐stabilised Na+? O2? complexes. 相似文献
10.
The paper analyses the effect of normal contact with friction on the generation of full band-gaps in sonic composites. The behavior of contact interfaces are computed by using LISA (local interaction simulation approach). LISA is an efficient tool for numerical simulation of the acoustic wave propagation in heterogeneous material specimens, in particular those with contact interfaces between different materials, like in sonic composites. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献