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71.
Sergey A. Krasnikov Sergey I. Bozhko Kevin Radican Olaf Lübben Barry E. Murphy Sundar-Raja Vadapoo Han-Chun Wu Mohamed Abid Valery N. Semenov lgor V. Shvets 《Nano Research》2011,4(2):194-203
The growth and ordering of C60 molecules on the WO2/W(110) surface have been studied by low-temperature scanning tunnelling microscopy and spectroscopy (STM and STS), low-energy
electron diffraction (LEED), and density functional theory (DFT) calculations. The results indicate the growth of a well-ordered
C60 layer on the WO2/W(110) surface in which the molecules form a close-packed hexagonal structure with a unit cell parameter equal to 0.95 nm.
The nucleation of the C60 layer starts at the substrate’s inner step edges. Low-temperature STM of C60 molecules performed at 78 K demonstrates well-resolved molecular orbitals within individual molecules. In the C60 monolayer on the WO2/W(110) surface, the molecules are aligned in one direction due to intermolecular interaction, as shown by the ordered molecular
orbitals of individual C60. STS data obtained from the C60 monolayer on the WO2/W(110) surface are in good agreement with DFT calculations. 相似文献
72.
Vladimir V Suchkov Ljubov A Vasserman Irina A Popello Valery Ya Grinberg Vladimir B Tolstoguzov 《Journal of the science of food and agriculture》1991,54(3):459-469
General regularity of preparation of fibrous textured protein from field bean globulin fraction by wet non-spinneret spinning and the water absorption capacity of the textured protein were investigated. The optimal conditions for this process for minimum protein loss in the coagulation bath were determined. Use of a highly concentrated neutral protein solution (>500 g litre?1) as a dope avoids the need for neutralisation and washing of the textured product. The textured protein obtained had a microfibrous structure. 相似文献
73.
Ekaterina S. Lokteva Aleksey E. LazhkoElena V. Golubina Vadim V. TimofeevAlexander V. Naumkin Tatiana V. YagodovskayaSergey N. Gaidamaka Valery V. Lunin 《The Journal of Supercritical Fluids》2011,58(2):263-271
Carbonaceous deposits formation was established as the primary reason of Pd/TiO2 catalyst deactivation during reductive processing of CCl4 to form hydrodechlorination and oligomerization products. Three methods of carbonaceous deposits elimination were tested: (1) extraction by supercritical CO2, (2) oxidation by ozone in supercritical CO2, and (3) low-temperature glow-discharge oxygen plasma treatment. Synchronic thermal analysis confirms effective carbonaceous deposits removal during regeneration by ozone or low temperature glow-discharge oxygen plasma; by XPS deep oxidation of surface Pd after oxidative treatment (by ozone or oxygen plasma) was found. Thus H2 reduction was proposed as the second step making possible full regeneration of initial catalytic activity of Pd/TiO2. 相似文献
74.
75.
Kirill V Chizh Valery A Chapnin Victor P Kalinushkin Vladimir Y Resnik Mikhail S Storozhevykh Vladimir A Yuryev 《Nanoscale research letters》2013,8(1):177
Nickel silicide Schottky diodes formed on polycrystalline Si 〈P〉 films are proposed as temperature sensors of monolithic uncooled microbolometer infrared focal plane arrays. The structure and composition of nickel silicide/polycrystalline silicon films synthesized in a low-temperature process are examined by means of transmission electron microscopy. The Ni silicide is identified as a multi-phase compound composed of 20% to 40% of Ni3Si, 30% to 60% of Ni2Si, and 10% to 30% of NiSi with probable minor content of NiSi2 at the silicide/poly-Si interface. Rectification ratios of the Schottky diodes vary from about 100 to about 20 for the temperature increasing from 22℃ to 70℃; they exceed 1,000 at 80 K. A barrier of around 0.95 eV is found to control the photovoltage spectra at room temperature. A set of barriers is observed in photo-electromotive force spectra at 80 K and attributed to the Ni silicide/poly-Si interface. Absolute values of temperature coefficients of voltage and current are found to vary from 0.3%℃ to 0.6%/℃ for forward bias and around 2.5%/℃ for reverse bias of the diodes. 相似文献
76.
Natalia Vinerot Yuheng Chen Vladimir V. Gridin Valery Bulatov Liviu Feller 《仪器科学与技术》2013,41(2):143-150
A new nondestructive analytical method for diagnosis of tooth caries is presented. The method is based on the Multiphoton Ionization (MPI) fast conductivity signals measured from tooth surfaces. The signals are acquired for a series of laser wavelengths, thus obtaining full MPI spectra. The results indicate a good correlation between the MPI results and the degree of severity of the caries, as diagnosed using traditional inspection. Moreover, the spectral information can be reduced (using least squares fitting) to a single parameter that provides an objective quantitative estimation of the caries severity. The MPI data can be obtained for tiny points on the dental surface and it is suggested that mapping is possible by scanning method. 相似文献
77.
Abstract A method for estimating the extent of tooth caries and providing imaging information based on Raman Spectral Imaging is suggested. This non‐destructive optical method is able to characterize and differentiate between normal enamel tooth surface, and initial and advanced tooth caries. Images and corresponding spectra were acquired from various tooth sites, and it was demonstrated that normal, white opaque, brown discoloured, and pitted tooth surfaces all have different distinct spectral features which characterize the different degrees of dental caries. Spectral analysis allows for detection of early changes in the surfaces of carious teeth, and the associated mapping capability allows for morphological characterization. It was found that the emission at 960 cm?1, which corresponds to PO stretching in the hydroxyapatite bond, is the most significant and can be used for diagnosis of caries. The emissions at 1070 cm?1 and at 590 cm?1 can also be applied, but are less accurate. The results suggest that this technique may be further developed and applied for clinical diagnosis of initial and more advanced demineralization processes of the enamel tooth surfaces. 相似文献
78.
The hybrid analytical–finite element model described in Part I is applied to predict the shear angle for a range of cutting velocity, uncut chip thickness, and two tool orthogonal rake angles. Experimental results and an empirical equation are also presented for the influence of the cutting conditions and cutting tool geometry on the chip–tool contact length. It is shown that there is a linear dependence between the chip–tool contact length/uncut chip thickness ratio and chip thickness/uncut chip thickness ratio over the range of cutting conditions assumed. The increase of the shear angle with the tool orthogonal rake is mostly due to the reduction of the specific shear energy in the primary shear zone and the specific friction energy in the secondary shear zone accompanied by a reduction of the chip–tool contact zone. The uncut chip thickness and cutting velocity influence the shear angle through their effect on the interface temperature and hence on the material flow stress in the secondary shear zone. The change in both parameters does not change significantly the specific shear energy in the primary shear zone. The model results are compared with the experimental results for a work material 0.18% C steel. The agreement between the predicted and experimental results is seen to be exceptionally good. 相似文献
79.
In metal cutting, the shear angle is considered as a fundamental parameter that defines the plastic deformation and the geometry of the process. The present paper presents a further development of the energy method for prediction of the shear angle in case of orthogonal metal cutting. Parallel-sided shear zone model is utilized to describe the geometry of chip formation. The material velocity in the primary shear zone is allowed to change gradually from the bulk material velocity to the chip velocity. The interaction between chip and tool in the secondary shear zone is modeled as sticking to sliding transition. The work material is characterized by an empirical equation, which allows for the influence of temperature, strain, and strain rate as well as their histories. To take into consideration the influence of the temperature on the work material properties, a finite element model (FEM) of heat transfer is employed. The FEM is developed as an adaptive model to reflect the change in the domain geometry. As the work material properties strongly depend on the temperature, an overall iterative calculation procedure including FEM is essential. In Part I, the theoretical basis of the model is described. In Part II the predicted values of the shear angle are compared with data from machining 0.18% C carbon steel over a range of cutting conditions and tool geometry. 相似文献
80.
Permyakov Sergei E.; Cherskaya Alexandra M.; Senin Ivan I.; Zargarov Aminullah A.; Shulga-Morskoy Sergey V.; Alekseev Andrey M.; Zinchenko Dmitry V.; Lipkin Valery M.; Philippov Pavel P.; Uversky Vladimir N.; Permyakov Eugene A. 《Protein engineering, design & selection : PEDS》2000,13(11):783-790
A molecule of the photoreceptor Ca2+-binding protein recoverincontains four potential EF-hand Ca2+-binding sites, of whichonly two, the second and the third, are capable of binding calciumions. We have studied the effects of substitutions in the second,third and fourth EF-hand sites of recoverin on its Ca2+-bindingproperties and some other characteristics, using intrinsic fluorescence,circular dichroism spectroscopy and differential scanning microcalorimetry.The interaction of the two operating binding sites of wild-typerecoverin with calcium increases the protein's thermal stability,but makes the environment around the tryptophan residues moreflexible. The amino acid substitution in the EF-hand 3 (E121Q)totally abolishes the high calcium affinity of recoverin, whilethe mutation in the EF-hand 2 (E85Q) causes only a moderatedecrease in calcium binding. Based on this evidence, we suggestthat the binding of calcium ions to recoverin is a sequentialprocess with the EF-hand 3 being filled first. Estimation ofCa2+-binding constants according to the sequential binding schemegave the values 3.7 x 106 and 3.1 x 105 M1 for thirdand second EF-hands, respectively. The substitutions in theEF-hand 2 or 3 (or in both the sites simultaneously) do notdisturb significantly either tertiary or secondary structureof the apo-protein. Amino acid substitutions, which have beendesigned to restore the calcium affinity of the EF-hand 4 (G160D,K161E, K162N, D165G and K166Q), increase the calcium capacityand affinity of recoverin but also perturb the protein structureand decrease the thermostability of its apo-form. 相似文献