Vortex Interaction with Large Particles in Bulk RE-123 Compounds

No Heading Excellent electromagnetic properties of ternary RE-123 compounds at low fields rely on vortex trapping at relatively large particles of secondary phases. Mechanism of vortex interaction with large particles, both in the single-vortex and multi-vortex regimes is studied. It is shown why the pinning effeciency is high at low magnetic fields but rapidly drops with increasing field.PACS numbers: 74.25. Qt, 74.25. Sv, 74.72.-h     

热塑性聚氨酯/尼龙612共混体系的相互作用及结晶行为

采用溶液共沉淀法制备了热塑性聚氨酯(TPU)/尼龙(PA)612共混物,通过变温红外光谱仪和差示扫描量热仪(DSC)研究了共混体系中 TPU与PA612分子间的相互作用及其对结晶行为的影响.DSC结果表明,随着共混体系中TPU含量的增加,PA612的结晶峰温度明显降低,结晶峰宽明显变宽;相对于纯TPU,共混体系中TPU...     

The Research of Spin-Orbital Interaction in Intermetallic Compounds of System Gd-In on Paramagnetic Area

Normal,R0,and anomalous,RS,components of the Hall coefficient are determined from the results of experimental investigations of temperature dependences of the H...     

Doping of Bi-Sr-Ca-Cu-O Compounds with Mn

Formation of the superconducting phases Bi-2212 and Bi-2223 has been studied for samples with nominal composition Bi_aPb_bMn_cSr₄Ca₅Cu₇O _x (a + b + c = 4). The influence of the stoichiometric replacement of Bi and/or Pb by Mn on the electric and magnetic properties of the Bi-based superconductors has been studied. The partial substitution of Mn for Bi in the samples without Pb did not promote the growth of the Bi-2223 phase. The samples with double substitution Pb-Mn for Bi revealed a large amount of the Bi-2223 phase.     

Interaction of caffeine with montmorillonite

In this study, caffeine was adsorbed onto montmorillonite and the surface of the montmorillonite was observed before and after the adsorption. Observations were performed by X-ray diffractometry (XRD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and scanning probe microscopy (SPM). Measurement of the interlayer distance by XRD revealed that it narrowed to 1.09?nm after caffeine adsorption. Adsorption of a small amount of caffeine causes a broadening of d₀₀₁ peaks. This suggested that caffeine molecules were adsorbed into the interlayer space in part, resulting in an irregular layer stacking. The results of SPM observations of caffeine-adsorbed montmorillonite showed the existence of protrusions that are different from minerals on the surface of montmorillonite and suggested a possibility that the protrusions were caffeine molecules adsorbed onto the surface of montmorillonite. DRIFTS demonstrated that the intensity of peaks assigned to Si–OH and siloxane decreased with the increase in the amount of caffeine adsorbed. These results suggested that caffeine molecules were adsorbed both into the interlayer space and onto the surface and interacted with Si–OH and siloxane, in particular. These findings will help us to select ions to be held in the interlayer space and organic compounds to improve the amount of adsorption when montmorillonite is used in the manufacture of caffeine-free drinks and foods.     

Interaction of NbVNi with Hydrogen

The interaction of NbVNi with hydrogen is studied over wide pressure and temperature ranges. Hydrogen absorption–desorption isotherms are measured, and the compositions of the resulting hydride phases are determined. X-ray diffraction analysis demonstrates that the incorporation of hydrogen into NbVNi leads to an isotropic expansion of its crystal lattice.     

Magnetic Ordering and Exchange Interaction of Laves Compounds Sm0.9Pr0.1（Fe1—xCox）2

Structure,magnetic properties and magnetostriction of Sm0.9Pr0.1(Fe1-xCox)2 compounds have been investi-gated by means of X-ray diffraction,a.c. initial susceptibility, extracting sample magnetometer,Mossbauer spec-troscopy and standard strain gauge techniques.The lattice parameter a of the MgCu2-type Laves compounds Sm0.9Pr0.1(Fe1-xCox)2 decreases nonlinearly with increasing Co concentration,deviating from the Vegardˊs law.Curie temperature Tc increases initially from 668 K for x=0 to 694 K for x=0.2 and then decreases to 200 K for x=1.0.The saturation magnetization Ms at temperatures 1.5K, 77K and 300K have the same variation tendency as the composition dependence of Curie temperature,in consistence with rigid-band model.The easy magnetization direction(EMD) od Sm0.9Pr0.1(Fe1-xCox)2 lies along [111] direction in the range x≤0.6,and changes to [110] for x=0.8 ,while Sm0.9Pr0.1(Fe1-xCox)2 stays in the paramagnetic state at room temperature.The composition dependence of the average hyperfine field,Hhf,demonstrates a similar variation tendency as that of the saturation magnetiza-tion Ms and Curie temperature Tc .The spontaneous magnetostricton λ111 increases with increasing Co content.The saturation magnetostriction λs decreases monotonically with increasing x,which is caused by the increase of magnetostriction constant λ100 with opposite sign to that of λ111.A two-sublattice model has been proposed to understand the intermediate region between the [111]and [110] spin configurations ,which can also be used to explain the temperature dependence of magnetization.     

Bosonic Clouds with Attractive Interaction Beyond the Local Interaction Approximation

We study the properties of a Bose–Einstein condensed cloud of atoms with negative scattering length confined in a harmonic trap. When a realistic non local (finite range) effective interaction is taken into account, we find that, besides the known low density metastable solution, a new branch of Bose condensate appears at higher density. This state is self–bound but its density can be quite low if the number N of atoms is not too big. The transition between the two classes of solutions as a function of N can be either sharp or smooth according to the ratio between the range of the attractive interaction and the length of the trap. A tight trap leads to a smooth transition. In addition to the energy and the shape of the cloud we study also the dynamics of the system. In particular, we study the frequencies of collective oscillation of the Bose condensate as a function of the number of atoms both in the local and in the non local case. Moreover, we consider the dynamics of the cloud when the external trap is switched off.     

Thermal Diffusivity of Compounds Loaded with Carbon Nanofibers

In this work, the thermal enhancement in silicone grease-based compounds as a function of carbon nanofiber (CNF) volume fraction was investigated. The thermal diffusivity of the samples was determined by a photopyroelectrical technique with a sample thickness scan. The results show that heat transport on these compounds strongly depends on the CNF volume fraction, due to the high thermal conductivity of CNF compared to the matrix; hence, a low loading percentage of the fibers produce a significant growth in the thermal diffusivity of the composite. The results show that the thermal diffusivity values of the CNF-silicone composite are comparable with commercial thermal compounds based on diamond and Ag microparticle fillers. The thermal conductivity of the samples was calculated, and its enhancement was analyzed using a modified Lewis–Nielsen model, taking into account the dependence of the maximum packing fraction and the form factor with the aspect ratio of the CNF. The influence of the Kapitza thermal resistance was discussed. These materials might find practical applications in systems in which the CNF improves the ebbing of heat away from semiconductor devices or in any other application in which heat dissipation is needed.     

Interaction of dispersed water with flame

The electric explosion of a wire in a thin-walled cylindrical glass ampule filled with water results in the formation of a disperse water (DW) cloud having a ring shape, which expands rapidly in the radial direction and slowly in the axial direction. Interaction of the DW with a flame produces fire quenching in the interaction zone. Experimental results are used for estimating the requirements and consumptions for creating DW clouds capable of quenching large-scale fires.     

Interaction of nanoparticles with lipid membrane

A nanoscale range of surface feature curvatures where lipid membranes lose integrity and form pores has been found experimentally. The pores were experimentally observed in the l-alpha-dimyristoyl phosphatidylcholine membrane around 1.2-22 nm polar nanoparticles deposited on mica surface. Lipid bilayer envelops or closely follows surface features with the curvatures outside of that region. This finding provides essential information for the understanding of nanoparticle-lipid membrane interaction, cytotoxicity, preparation of biomolecular templates and supported lipid membranes on rough and patterned surfaces.     

Interaction of liquid gallium with copper

The mechanism of the interaction of liquid gallium with copper powder at 100°C was studied. Data on the characteristics of the growth of the -phase (the compound CuGa₂) were used to develop a method of calculating the effective thickness of intermetallic compound layers formed as a result of the interaction between liquid metals and metal powders and an appropriate formula was derived. It was established that the growth of the -phase formed as a result of the interaction in liquid gallium and copper at 100°C follows a parabolic law.Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 5, No. 6, pp. 699–703, November–December, 1969.     

Interaction of sodium with simple glasses

The interactions of binary and ternary silicates with sodium were found to be similar to that of vitreous silica in that the number of Si-O^– bonds was observed to increase at the expense of the Si-O bonds as the temperature of exposure to sodium is raised. From the model developed for vitreous silica [1], it was argued that Si-O^– bonds are more stable than Si-O bonds in the presence of sodium. Using this concept, the discoloration behaviour of these binary and ternary silicates could be explained. The more general problem of selecting materials compatible with sodium is also dealt with by collecting a set of criteria based on equilibrium thermodynamics, and the shortcomings of these criteria are discussed.     

Interaction of sodium with simple glasses

The discolouration of vitreous silica by sodium was viewed as a surface phenomenon, hence techniques such as electron spectroscopy for chemical analysis (ESCA) and infra-red reflection spectroscopy (IRRS) along with a variety of other analytical tools were used to investigate the interaction. When vitreous silica was exposed to sodium vapour at about 300 C, the formation of Si-O^– bonds were observed. In addition sodium which had diffused into the glass was found to be in an ionic state. At a higher temperature of exposure to sodium, about 450 C, crystalline sodium metasilicate (and possibly silicon) was formed. Using the experimental results presented here and elsewhere, a model has been developed based on the formation of sodium metasilicate and non-stoichiometric silicon oxide when vitreous silica is exposed to sodium vapour. The discolouration phenomenon is attributed solely to the formation of non-stoichiometric silicon oxide.     

Interaction of noise with excitable dynamics

In this paper, the interaction of noise with excitable dynamics of a three-electrode electrochemical cell is examined. Different scenarios involving both external and internal noise sources are considered. In the case of external noise, aperiodic stochastic resonance and regulation of the noise-induced spiking behaviour are investigated. In the case of internal noise, the interaction of intrinsic electrochemical noise with autonomous nonlinear dynamics is studied. The amplitude of this internal noise, determined by the concentration of chloride ions, is monotonically increased and the provoked dynamics are analysed. Our results indicate that internal noise, similar to its external counterpart, is able to induce regularity in the system response.     

Interaction of TiW film with GaAs

The interactions of co-evaporated Ti_0.3W_0.7 films with GaAs have been studied after annealing at temperatures in the range of 650 to 900° C for 15 min employing Rutherford backscattering, transmission and scanning electron microscopy. X-ray diffraction and energy-dispersive X-ray analysis techniques. Reaction has been found to take place at 650° C as evidenced by the presence of an AsTi compound in the region near the interface of TiW film and GaAs. Gallium diffuses out to the surface at temperatures above 750° C and causes surface morphological degradation, which can be related to the instability of the TiW Schottky barrier height at higher temperatures 750° C as reported in the literature.