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1.
F. Le Normand C.S. Cojocaru O. Ersen L. Gangloff R. Alexandrescu I. Morjan 《Applied Surface Science》2007,254(4):1058-1066
Iron-based nanoparticles are prepared by a laser-induced chemical vapor deposition (CVD) process. They are characterized as body-centered Fe and Fe2O3 (maghemite/magnetite) particles with sizes ≤5 and 10 nm, respectively. The Fe particles are embedded in a protective carbon matrix. Both kind of particles are dispersed by spin-coating on SiO2/Si(1 0 0) flat substrates. They are used as catalyst to grow carbon nanotubes by a plasma- and filaments-assisted catalytic CVD process (PE-HF-CCVD). Vertically oriented and thin carbon nanotubes (CNTs) were grown with few differences between the two samples, except the diameter in relation to the initial size of the iron particles, and the density. The electron field emission of these samples exhibit quite interesting behavior with a low turn-on voltage at around 1 V/μm. 相似文献
2.
Popescu C. Voicu I. Alexandrescu R. Morjan I. Dumitras D. Popescu M. Fatu D. 《Journal of Thermal Analysis and Calorimetry》1999,56(1):183-189
This paper reports on the synthesis of various iron oxides by the IR laser processing of different iron salts. X-ray diffraction
techniques were used to characterize the reaction products. Some differences in terms of crystallite size and isotropy between
these oxides and those obtained from the same salt by thermal means are described and explained.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
R. Alexandrescu J. Morjan C. Grigoriu I. N. Mihailescu Z. Bastl J. Tlaskal R. Mayer J. Pola 《Applied Physics A: Materials Science & Processing》1988,46(4):275-279
Infrared multiphoton decomposition of monosilane in the presence of methyl methacrylate results in the formation of gaseous methane, acetylene, butenes and carbon monoxide along with a solid polymer whose chemical mechanism of formation is discussed in line of the poly(dimethylsiloxane) structure inferred from ESCA and IR spectral analysis. 相似文献
4.
I. Ursu R. Alexandrescu V. Drăgănescu C. Grigoriu I. N. Mihăilescu I. Morjan A. M. Prokhorov N. V. Karlov A. S. Lagutchev A. N. Orlov Yu. N. Petrov 《Applied physics. B, Lasers and optics》1988,47(1):61-65
New experimental results are reported pointing to the possibility of a laser control of the resonant gases transit through capillaries in the Knudsen and intermediate regimes. 相似文献
5.
I. Morjan I. Soare R. Alexandrescu R.-E. Morjan L. Gavrila-Florescu G. Prodan I. Sandu E. Popovici F. Dumitrache I. Voicu M. Scarisoreanu 《Physica E: Low-dimensional Systems and Nanostructures》2007,37(1-2):26
We report about the synthesis of carbon nanotubes by catalytic LCVD (C-LCVD), using a CW CO2 laser and alternatively, C2H2/C2H4/NH3 and C2H2/C2H4-containing gas mixtures. Different core–shell Fe–C nanocomposites (as synthesized and toluene extracted) were used employed as catalysts. The nanotubes grown from Fe–C residue demonstrate the lowest mean diameters. Prevalent curled and coiled morphologies are obtained for the CNTs grown in the presence of ammonia. 相似文献
6.
Moldovan Z Stoica C Hillebrand M Alexandrescu L Macovescu G 《Analytical and bioanalytical chemistry》2005,381(7):1381-1386
Phenyl--naphthylamine (PBN) used as rubber antioxidant was found to have native fluorescence. A spectrofluorimetric method for determination of PBN in multicomponent mixtures of polymer additives is described. The apparent excitation and fluorescence wavelengths used are 348 and 413.5 nm, respectively. Maximum fluorescence intensity is obtained by irradiating PBN dissolved in ethanol, at room temperature. The fluorescence varies linearly with the concentration of PBN in the range of 0.04–4 g mL–1. The accuracy and precision of the method are reported. 相似文献
7.
Z. Moldovan L. Alexandrescu I. Vasilescu L. Radu 《Journal of the Iranian Chemical Society》2006,3(4):305-311
The title compound, 1,2-dihydro-2,2,4-trimethylquinoline (TMQ), is a quinoline family member and is among others used to prevent the oxidative degradation of polymers. TMQ has been characterized by its fluorescence emission. In this work the effects of solvent, acidity, continuous irradiation and the influence of some interferents upon the fluorescence intensity of TMQ were investigated. Under the selected conditions (in propan-1-ol solution at λexcitation/λemission = 334 nm/412 nm), the fluorescence intensity is proportional to the concentration of TMQ over the range 0.05–5 μg ml?1 with a correlation coefficient of 0.9963. The proposed method was applied to the determination of TMQ in synthetic mixtures of polymer additives and specific rubber samples. 相似文献
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9.
We derive the interaction Hamiltonian between a diatomic molecule and a Laguerre-Gaussian beam under the assumption of a small spread of the center of mass wave function of the molecule in comparison with the beam waist. Considering the dynamical variables of the center of mass, vibrational, rotational, and electronic motion, we show that, within the electronic dipole approximation, the orbital angular momentum of the field couples with the rotational and electronic motion. The changes in the transition probabilities and selection rules induced by the field orbital angular momentum and the applicability of the derived interaction mechanisms for polyatomic molecules are discussed. 相似文献
10.
B. David M. Vondrá?ek O. Schneeweiss P. Bezdi?ka R. Alexandrescu 《Journal of nanoparticle research》1999,1(4):522-522