نتایج جستجو برای: acetylene
تعداد نتایج: 3543 فیلتر نتایج به سال:
An acetylene black electrode modified by an adsorbed cationic surfactant, cetyltrimethylammonium bromide (CTAB), was developed. The influences of various types of surfactants on the electroreduction of O2 were investigated. It was demonstrated that a cationic surfactant, CTAB, on the surface of the electrode could significantly decrease the overpotential of dioxygen reduction, and the reduction...
Formation of C–H H–B dihydrogen bonded complexes of acetylene, fluoroacetylene, chloroacetylene, and cyanoacetylene with borane-trimethylamine were investigated with MP2 and B3LYP methods using 6-311++G(d,p) and aug-cc-pVDZ basis sets. The stabilization energies ranged from 6–20 kJ mol . NBO analysis predicts transfer of charge from r B–H bonding orbital to r* C–H anti-bonding orbital. It was a...
The Composite Infrared Spectrometer observed Jupiter in the thermal infrared during the swing-by of the Cassini spacecraft. Results include the detection of two new stratospheric species, the methyl radical and diacetylene, gaseous species present in the north and south auroral infrared hot spots; determination of the variations with latitude of acetylene and ethane, the latter a tracer of atmo...
The relative contents of Cu+ and Cu2+ in solutions of anhydrous Nieuwland catalyst and CuCl2-added anhydrous Nieuwland catalyst were detected by X-ray photoelectron spectroscopy (XPS). Results indicated that Cu+ could be transformed into Cu2+ during the process of acetylene dimerization into monovinylacetylene, leading to deactivation of the catalyst. Moreover, the addition of Cu2+ inhibited th...
For EPR measurements of RNA, DNA, or proteins, the occurrence of the paramagnetic species is necessary. The aim of this work is to improve the synthesis of two different EPR spinlabels 2,2,6,6-tetra methyl-3,4-dehydro-piperidin-N-oxyl-4-acetylene (TEMPA) 6 and 15N-labeled TEMPA 6* and their coupling to uridine. The yield of the synthesis of TEMPA could be increased to 40% and the second nitroxi...
An instrument for the measurement of absolute dissociative electron attachment cross sections was constructed and applied to two prototype molecules, acetylene (C2H2) and deuterated acetylene (C2D2). The isotope effect at the first dissociative electron attachment band at 3 eV was determined--the cross section for C2D-/C2D2 is 14.4 times smaller than that for C2H-/C2H2. The results play a centr...
We study the energetics of acetylene (C2H2) molecules inside a carbon nanotube (CNT) using the ab initio pseudopotential method. The encapsulation energy of a single C2H2 molecule into the nanotube and the formation energy of (C2H2) n @CNT are calculated. We investigate whether a polyacetylene chain can be produced by fusion of the close-packed acetylene molecules inside the CNT and find that t...
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