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31.
Standard graphite TIMREX® SLX 50 was oxidised at 500–800 °C under air atmosphere in a muffle and a rotary furnace. Scanning Electron Microscopy (SEM), Raman spectroscopy, and X-Ray Powder Diffraction (XRD) were used to study the changes in surface morphology and crystallinity. The results show a slight increase of the La value and a decrease of the rhombohedral fraction with increased heat-treatment temperature (HTT). XRD measurements show no significant change in La values within the bulk of graphite samples. Above 700 °C SEM images of graphite reveals holes and cavities, whereas heat-treatment temperatures below 700 °C do not significantly affect graphite materials parameters. 相似文献
32.
K
β-to-K
α X-ray intensity ratios of Fe and Ni in pure metals and in Fe
x
Ni1−x
alloys (x=0.20, 0.50, 0.58) exhibiting similar crystalline structure have been measured following excitation by 59.54 keV γ-rays from a 241Am point source, to understand as to why the properties of permalloy Fe0.2Ni0.8 is distinct from other alloy compositions. It is observed that the valence electronic structure of Fe0.2Ni0.8 alloy is totally different from other alloys which may be attributed to its special magnetic properties. 相似文献
33.
34.
Forward particle production in π−
p andK
−
p collisions at 58 GeV/c and comparison with quark models
F. Pauß A. Gonzalez-Arroyo W. Ochs B. Alper G. Blanar M. Cerrada V. Chabaud C. Damerell C. Daum H. Dietl A. Gillman C. Hardwick W. Hoogland R. Klanner J. Loken E. Lorenz G. Lütjens G. Lutz W. Männer G. Polok M. Rozanska W. Spalding U. Stierlin G. Thompson H. Tiecke J. Turnau P. Weilhammer F. Wickens ACCMOR Collaboration 《Zeitschrift fur Physik C Particles and Fields》1985,27(2):211-232
We present single inclusive π±, π0 andK ± spectra in the forward fragmentation region (x>0.2,p T <1.5 GeV/c) as well as correlations between two charged particles. The data were recorded in an unseparated negative hadron beam at the CERN SPS using a large acceptance forward spectrometer. Our maasurements are compared in detail with several models which emphasise the role of the beam valence quarks in this production process. The connection to measurements at largep T is also investigated. 相似文献
35.
The vibrational structure of the 2B1 ← 2A1 system of NO2 has been assigned to a progression in ν′2. Vibrational analyses for three isotopic species have been made using a hamiltonian which allows explicitly for a large-amplitude bending vibration. The system origin for the normal isotopic species has been assigned an extrapolated value of 14743.5 cm?1. The bending potential function is expressed as a rapidly converging Taylor series expansion about the linear configuration. There is no evidence that the equilibrium configuration is nonlinear. 相似文献
36.
37.
Solvent‐Mediated Control of the Electrochemical Discharge Products of Non‐Aqueous Sodium–Oxygen Electrochemistry
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Iain M. Aldous Dr. Laurence J. Hardwick 《Angewandte Chemie (International ed. in English)》2016,55(29):8254-8257
The reduction of dioxygen in the presence of sodium cations can be tuned to give either sodium superoxide or sodium peroxide discharge products at the electrode surface. Control of the mechanistic direction of these processes may enhance the ability to tailor the energy density of sodium–oxygen batteries (NaO2: 1071 Wh kg?1 and Na2O2: 1505 Wh kg?1). Through spectroelectrochemical analysis of a range of non‐aqueous solvents, we describe the dependence of these processes on the electrolyte solvent and subsequent interactions formed between Na+ and O2?. The solvents ability to form and remove [Na+‐O2?]ads based on Gutmann donor number influences the final discharge product and mechanism of the cell. Utilizing surface‐enhanced Raman spectroscopy and electrochemical techniques, we demonstrate an analysis of the response of Na‐O2 cell chemistry with sulfoxide, amide, ether, and nitrile electrolyte solvents. 相似文献
38.
39.
Micol Santi Jakob Seitz Rossana Cicala Tomas Hardwick Dr. Nisar Ahmed Prof. Dr. Thomas Wirth 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(71):16230-16235
Amino acid derivatives undergo non-Kolbe electrolysis to afford enantiomerically enriched α-alkoxyamino derivatives through intermediate chiral carbenium ions. The products contain N,O-acetals which are important structural motifs found in bioactive natural products. The reaction is performed in a continuous flow electrochemical reactor coupled to a 2D-HPLC for immediate online analysis. This allowed a fast screening of temperature, electrode material, current, flow-rate and concentration in a DoE approach. The combination with online HPLC demonstrates that also stereoselective reactions can benefit from a hugely accelerated optimisation by combining flow electrochemistry with multidimensional analysis. 相似文献
40.
Hardwick JA Pavelka LC Baines KM 《Dalton transactions (Cambridge, England : 2003)》2012,41(2):609-621
The addition of a series of primary and secondary amides to the group 14 (di)metallenes Mes(2)Si=SiMes(2), Mes(2)Ge=GeMes(2) and (Me(3)Si)(2)Si=C(OSiMe(3))R, where R = t-Bu or R = 1-Ad, was examined. In general, the addition of primary and N-methyl amides gave amide adducts whereas the addition of N-phenyl amides gave imidate adducts. The regiochemistry of the additions was highly dependent upon the substituent bonded to the amide nitrogen. We propose that the formation of the adducts proceeds by way of a zwitterionic intermediate. The reactivity of tetramesityldigermene towards amides is used to predict the structure of the amide adducts formed on the Ge(100)-2 × 1 surface. 相似文献