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201.
Coronene Encapsulation in Single‐Walled Carbon Nanotubes: Stacked Columns,Peapods, and Nanoribbons 下载免费PDF全文
Dr. Ilya V. Anoshkin Dr. Alexandr V. Talyzin Prof. Albert G. Nasibulin Dr. Arkady V. Krasheninnikov Hua Jiang Prof. Risto M. Nieminen Prof. Esko I. Kauppinen 《Chemphyschem》2014,15(8):1660-1665
Encapsulation of coronene inside single‐walled carbon nanotubes (SWNTs) was studied under various conditions. Under high vacuum, two main types of molecular encapsulation were observed by using transmission electron microscopy: coronene dimers and molecular stacking columns perpendicular or tilted (45–60°) with regard to the axis of the SWNTs. A relatively small number of short nanoribbons or polymerized coronene molecular chains were observed. However, experiments performed under an argon atmosphere (0.17 MPa) revealed reactions between the coronene molecules and the formation of hydrogen‐terminated graphene nanoribbons. It was also observed that the morphology of the encapsulated products depend on the diameter of the SWNTs. The experimental results are explained by using density functional theory calculations through the energies of the coronene molecules inside the SWNTs, which depend on the orientation of the molecules and the diameter of the tubes. 相似文献
202.
Liudmila E. Tsygankova Vladimir I. Vigdorovich Alexandr A. Uryadnikov Michael V. Vigdorowitsch Evgeniia Yu. Shel Marina N. Uryadnikova 《Surface and interface analysis : SIA》2020,52(12):855-858
Corrosion and kinetics of partial electrode reactions on carbon steel St3 with superhydrophobic coatings of three types were studied in 0.5 M NaCl and 50 g/L NaCl +400 mg/L H2S solutions. The investigations were carried out on electrodes made of carbon steel St3 with a chemical composition, wt. %: C – 0.20; Mn – 0.50; Si – 0.15; P – 0.04; S – 0.05; Cr – 0.30; Ni – 0.20; Cu – 0.20, and Fe – 98.36. To obtain the type I coating, the metal surface was textured by an IR laser radiation of nanosecond duration followed by chemisorption of fluorobutylsilane out of a solution in n-decane. To obtain a coating of type II, a nanoscale composite layer consisting of aggregates of aerosil nanoparticles was applied additionally to the outcome of type I method. To obtain a coating of type III, the metal surface after being textured by the infrared (IR) laser radiation of nanosecond duration was followed by chemisorption of fluoroxy silane. The influence of duration τ of the medium corrosive impact on protective effect of the superhydrophobic coating is considered. It was shown that upon reaching a steady state (after 72 h), the corrosion rate of steel with a superhydrophobic coating of I and II types in a 0.5 M NaCl solution is reduced by 23 ± 3 times compared with unprotected samples. Approximately the same picture is characteristic of electrodes with a coating of type III in a solution of 50 g/L NaCl +400 mg/L H2S. 相似文献
203.
Alexandr S. Mishchenko 《Central European Journal of Mathematics》2005,3(4):766-793
These notes represent the subject of five lectures which were delivered as a minicourse during the VI conference in Krynica,
Poland, “Geometry and Topology of Manifolds”, May, 2–8, 2004. 相似文献
204.
Evgeny K. Dolgov Vadim A. Bataev Alexandr V. Abramenkov 《Journal of Molecular Spectroscopy》2005,230(1):43-53
Various non-empirical methods for estimating the parameters of one-dimensional internal rotation potentials and energies of torsional transitions were compared for the CX3NO molecules (X = H, D, F) in the ground (S0) and lowest excited singlet (S1) electronic states. The potential energy surfaces were studied by the ab initio MR-AQCC/cc-pVTZ, MR-AQCC/cc-pVTZ(-f), MP2/6-311G(2d), and MP2/6-311G(d,p) methods. The one-dimensional internal rotation problem was solved using the following models: (1) geometry optimization at a given internal rotation coordinate; (2) intrinsic reaction path; (3) gradient extremal; and (4) use of only the data on potential energy surface stationary points. Special attention was paid to the problem of calculation of kinematic coefficient. In all cases, the calculated torsional energies for CX3NO molecules (X = H, D, F) are in agreement with experiment. The results from different methods for constructing torsional cross-sections of the potential energy surface are virtually equivalent and differ insignificantly from the results of calculations within the framework of the simplest model, hence, estimates of the barrier to internal rotation are of most importance. It was found that a change in the zero-point energy could give a correction to the internal rotation potential as large as 15% of the potential barrier. However, in the case under consideration the calculations in the harmonic approximation taking into account this correction do not improve the agreement between the calculated torsional transitions and the experimental data. 相似文献
205.
The molecular structure of the interfaces between pure CnH2n+2 (n=10, 12, 14, 16) and Au(1 1 1) surface has been studied by scanning tunneling microscopy. At 291 K, self-organized monolayers with a lamella structure are formed with these alkanes. The ordered monolayers are melting at temperature higher by 46, 28, 15, 5 K than the melting point of bulk CnH2n+2 crystals with n=10, 12, 14, 16, respectively. Two kinds of melting process were observed: (i) a direct solid/liquid phase transition within the monolayer for C10H22, C12H26 and C14H30 molecules, (ii) an intermediate phase for C16H34 molecules. This mesophase corresponds to a two-dimensional liquid crystal formed by molecules moving along their axis and along Au1 1 0. These results agree well with calculations using a geometric model taking in account the misfit between the CH2–CH2–CH2 period along alkyl chain and the gold lattice along 1 1 0 direction. 相似文献
206.
Alexandr O. Ivanov 《European Journal of Combinatorics》2002,23(8):949
We investigate extremal networks of the Manhattan length functional. We give a criterion of that a local minimal network in the sense of the Manhattan length is a critical network with respect to the Manhattan length functional. It turns out that the critical condition is non-local. 相似文献
207.
K. G. Bychik A. S. Voloshko E. E. Sil’nikov Alexey A. Sysoev Alexandr A. Sysoev 《Journal of Analytical Chemistry》2011,66(14):1455-1463
In laser time-of-flight mass spectrometers, satisfactory resolution by weight is achieved for a fixed initial kinetic energy
acquired by the ions in the plasma. The integration of mass spectra in a wide energy range intended for obtaining satisfactory
results of analysis leads to a 3–5-fold reduction of the resolving capacity. In the case of the LAMAS-10 device, the resolution
for W = 50–300 eV energy dispersion of the ions varies from R ∼ 1000 (for W = 300 eV) to R ∼ 150 (for W = 50 eV), such values being insufficient for quantitative elemental analysis. It has been demonstrated that the main reason
for the differences in the resolution values for LAMAS-10 are time aberrations by energies in the laser plasma drift space.
The modification of the ion optics theory for LAMAS-10 allows the determination of the principles of the influence of the
initial ion energies generated in the laser plasma on the resolution. The dependence of the conditions of the time focusing
of ions by energies has been determined in a wide range of the initial values. This dependence provides software-controlled
readjustment of the time focusing before the registration of the mass spectra for each initial ion energy. When time focusing
of the ions was performed in a wide range of the initial energies, the resolution increased to R = 1300 at W = 50 eV, such parameters providing the quantitative analysis of solid bodies and powders. 相似文献
208.
Antonov AS Avilov SA Kalinovsky AI Dmitrenok PS Kalinin VI Taboada S Ballesteros M Avila C 《Natural product research》2011,25(14):1324-1333
Two new minor triterpene glycosides, liouvillosides A(4) (1) and A(5) (2) have been isolated from the sea cucumber Staurocucumis liouvillei living in Antarctic and Sub-Antarctic waters. The structures of the new glycosides were elucidated using extensive nuclear magnetic resonance (NMR) spectroscopy ((1)H- and (13)C-NMR spectroscopy, (1)H-(1)H COSY, 1D-TOCSY, HMBC, HSQC and NOESY), ESI-MS and MALDI TOF MS. The glycosides 1 and 2 are disulphated tetraosides having very rare 3-O-methylquinovose as terminal monosaccharide. 相似文献
209.
Alexandr Gre?enko 《Journal of Terramechanics》2011,48(5):325-332
Every element of a pulling traction device (e.g. track shoe with grouser or tire section with lug) exhibits increasing rearward displacement during its engagement with soft ground. Compression–Sliding (CS) approach states in agreement with experimental evidence that on common soft ground this displacement starts due to longitudinal soil compression by the grouser or lug, which steadily increases up to the transitional displacement when the soil segment beneath a driving element fails in shear. Further displacement of a driving element is marked by forced slide of a sheared off soil block, which may eventually collapse. There was justified reasoning that the transitional displacement depends not only on the grouser (lug) contact pressure but also on the area and load of the respective traction element. The presented article reports on experiments designed to test this premise. The measurements applying the novel double plate (DP) meter technique were carried out in a laboratory soil bin containing loam charge of uniform bulk density and moisture content. Three sizes (proportions 1:2:4) and two mean vertical contact pressures (ratio1:2) of DP meter main plate were tested. The analysis of performed experiments confirmed the existence of dimensional and loading relationship “main plate – transitional displacement”, which bears upon the evaluation of thrust–slip relationship of any traction device by the CS approach or by any other method observing the existence of displacement. 相似文献
210.
Let S(m|n,r)Z be a Z-form of a Schur superalgebra S(m|n,r) generated by elements ξi,j. We solve a problem of Muir and describe a Z-form of a simple S(m|n,r)-module Dλ,Q over the field Q of rational numbers, under the action of S(m|n,r)Z. This Z-form is the Z-span of modified bideterminants [T?:Ti] defined in this work. We also prove that each [T?:Ti] is a Z-linear combination of modified bideterminants corresponding to (m|n)-semistandard tableaux Ti. 相似文献