Dynamic wettability of wood surface modified by acidic dyestuff and fixing agent

Acidic dyestuffs can bring brilliant colors to the wood and fixing agents can avoid the color loss. They could change the surface wettability of wood, which impact the gluing process of veneers. In condition of the higher moisture content of wood, the rare veneers, the veneers dyed by acidic dyestuffs and the dyed veneers fixed by Chitosan were glued respectively by one-component wet-curing isocyanate adhesive and the contact angles (θ) of the different gluing interfaces were measured. The dynamic wettability of these gluing interfaces was characterized by both the contact angle θ and the spreading-penetration parameter (K) calculated by θ. The results showed that the θ-values decreased significantly with the extension of time and the initial contact angles (θ_i) decreased with the moisture contents of veneers increasing, but the variation of the balance contact angles (θ_e) was reversed with θ_i. When the moisture contents of veneers were same, the variation of θ of the rare veneers was minimal and the variation of θ of the fixed veneers was maximal. The K-values of these gluing interfaces all decreased significantly with the moisture contents of veneers increasing, but the variations of K were different. The wetting model describing the dynamic wetting process was established on the basis of these variations.     

Interaction of a high-order Bessel beam with a submerged spherical ultrasound contrast agent shell - Scattering theory

Background and objective

Acoustic scattering properties of ultrasound contrast agents are useful in extending existing or developing new techniques for biomedical imaging applications. A useful first step in this direction is to investigate the acoustic scattering of a new class of acoustic beams, known as helicoidal high-order Bessel beams, to improve the understanding of their scattering characteristics by an ultrasound contrast agent, which at present is very limited.

Method

The transverse acoustic scattering of a commercially available albuminoidal ultrasound contrast agent shell filled with air or a denser gas such as perfluoropropane and placed in a helicoidal Bessel beam of any order is examined numerically. The shell is assumed to possess an outer radius a = 3.5 microns and a thickness of ∼105 nm. Moduli of the total and resonance transverse acoustic scattering form functions are numerically evaluated in the bandwidth 0 < ka? 3, which corresponds to a frequency bandwidth of 0-205 MHz that covers a wide range of applications for imaging with contrast agents. Particular attention is paid to the shell’s material, the content of its interior hollow region and the fluid surrounding its exterior. The contrast agent shell is assumed to be immersed in an ideal compressible fluid so the viscous corrections are not considered. Analytical equations are derived and numerical calculations of the total and resonance form functions are performed with particular emphasis on the effect of varying the half-cone angle, the order of the helicoidal Bessel beam as well as the fluid that fills the interior hollow space.

Results and conclusion

It is shown that shell wave resonance modes can be excited on an encapsulated micro-bubble. The forward and backscattering vanish for a helicoidal high-order Bessel beam. Additionally, the fluid filling the inner core affects the shell’s response significantly. Moreover, there is no monopole contribution to the axial scattering of a helicoidal Bessel beam of order m ? 1 so that the dynamics of contrast agents would be significantly altered. The main finding of the present theory is the suppression or enhancement for a particular resonance that may be used to advantage in imaging with ultrasound contrast agents for clinical applications.     

Controlled hydrothermal growth of ZnO nanostructures by sequestering the Zn metal ions with the chelating agent EDTA

In the present work, a controlled growth of ZnO nanostructures by manipulating Zn metal ion concentration by the chelating action of ethylene diaminetetra acetic acid in hydrothermal method is studied. EDTA produces metal–chelate complex by the formation of bidentate ligand with Zn²⁺ in the solution and diminishes the reactivity of Zn metal cations. Concentration of EDTA in the mother solution was varied in different ranges like 3, 5 and 10 mM while retaining the zinc metal salt and the NaOH concentration the same. Three different morphologies of wurtzite structured ZnO nanostructures such as nanorods-bunch, separate/discrete uniformly sized hexagonal nanorods and tapered flower petals like shapes are achieved by 3, 5 and 10 mM strengths of EDTA, respectively. The medium concentration 5 mM of EDTA is found to have moderate control over producing ZnO nanostructures of uniform diameter and a high aspect (length to diameter) ratio. An array of vertically aligned free standing ZnO nanorods with uniform spacing is successfully achieved by the addition of 5 mM of EDTA in the mother solution and the same is studied for its fluorescence property at an excitation of 325 nm and it has exhibited a characteristic UV emission of ZnO around 383 nm.     

Interaction of aluminum with the rhenium surface: Adsorption, desorption, and growth of surface compounds

The interaction of aluminum with the ( $10\bar 10$ ) rhenium surface was studied experimentally within a broad temperature range, 300–2000 K. Surface aluminide (SA) ReAl with a concentration of adsorbed Al atoms N _Al=1.6×10¹⁵ cm^?2 was found to form. It was shown that aluminum escapes from the surface by thermal desorption at temperatures from 1300 to 1600 K, with the desorption activation energy changing abruptly from ～3.6 to ～4.2 eV when passing through the concentration corresponding to the SA.     

Interaction of neutrons with nanoparticles

Two hypotheses concerning the interaction of neutrons with nanoparticles and having applications in the physics of ultracold neutrons (UCN) are considered. In 1997, it was found that, upon reflection from the sample surface or spectrometer walls, UCN change their energy by about 10^?7 eV with a probability of 10^?7–10^?5 per collision. The nature of this phenomenon is not clear at present. Probably, it is due to the inelastic coherent scattering of UCN on nanoparticles or nanostructures weakly attached at the surface, in a state of Brownian thermal motion. An analysis of experimental data on the basis of this model allows one to estimate the mass of such nanoparticles and nanostructures at 10⁷ a.u. The proposed hypothesis indicates a method for studying the dynamics of nanoparticles and nanostructures and, accordingly, their interactions with the surface or with one another, this method being selective in their sizes. In all experiments with UCN, the trap-wall temperature was much higher than a temperature of about 1 mK, which corresponds to the UCN energy. Therefore, UCN increased their energy. The surface density of weakly attached nanoparticles was low. If, however, the nanoparticle temperature is lower than the neutron temperature and if the nanoparticle density is high, the problem of interaction of neutrons with nanoparticles is inverted. In this case, the neutrons of initial velocity below 10² m/s can cool down, under certain conditions, owing to their scattering on ultracold heavy-water, deuterium, and oxygen nanoparticles to their temperature of about 1 mK, with the result that the UCN density increases by many orders of magnitude.     

Interaction of mesons with deuterons

The problems of studying the form of the elementary meson-nucleon interaction as well as of the nuclear structure are discussed for the case of absorption of negative muons and pions in deuterium with an emphasis on obtaining information on the nucleon-nucleon forces.Invited talk at the symposium Theory of lightest nuclei, Liblice, Czechoslovakia, May 1974.     

番茄红素与牛血清白蛋白的相互作用

采用荧光光谱法研究了番茄红素(Lycopene)与牛血清白蛋白(BSA)的相互作用关系。研究表明,番茄红素能使BSA在340nm(λem)处产生荧光猝灭,猝灭机理为静态猝灭。pH=7.4,温度为293K时,猝灭时表观结合常数KA为5.33×104L.mol-1,结合位点数n为0.6461,同时荧光猝灭最大速率常数Kq=2.76×1012L.mol-1.s-1。二者呈自发结合且主要作用力为氢键和范德华力,结合距离r与能量转移效率E分别为5.6nm和0.098,偏酸性或碱性的条件使番茄红素与BSA的结合常数增加。     

Interaction of the Light Field with N Atoms Possessing Dipole-dipole Interaction

The interaction of the light field with two-level atoms possessing dipole-dipole interaction is studied. It is shown that a light field at coherent state can produce a squeezed atom laser.     

Interaction of the Light Field with N Atoms Possessing Dipole-dipole Interaction

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A kinetic investigation on low-temperature ignition of propane with ozone addition in an RCM

To extend the temperature for propane ignition to a lower region (< 680 K), ozone (O₃) was used as an ignition promoter to investigate the low-temperature chemistry of propane. Ignition delay times for propane containing varying concentrations of O₃ (0, 100, and 1000 ppm) were measured at 25 bar, 654–882 K, and equivalence ratios of 0.5 and 1.0 in a rapid compression machine (RCM). Species profiles during propane ignition with varying O₃ concentrations were recorded using a fast sampling system combined with a gas chromatograph (GC). A kinetic model for propane ignition with O₃ was developed. O₃ shortened ignition delay times of propane significantly, and the NTC behavior was weakened. O atoms released from O₃ reacted with propane through hydrogen abstraction reactions, which led to the fast production of OH radicals. The following oxidation of fuel radicals generated additional OH radicals. Consequently, the inhibition caused by the slow chemistry of hydrogen peroxide (H₂O₂) in the NTC region was weakened in the presence of O₃. Experimental results with O₃ addition can provide extra constraints on the low-temperature chemistry of propane. Species profiles during propane ignition at 730 K with 1000 ppm O₃ addition showed the production of propanal (C₂H₅CHO), acetone (CH₃COCH₃), and acetaldehyde (CH₃CHO) was promoted significantly. Model analyses indicated that O₃ shifted the oxidation temperature of propane to a lower region, in which reactions of ROO radicals (NC₃H₇O₂ and IC₃H₇O₂) tend to generate RO radicals (NC₃H₇O and IC₃H₇O). The promotion of RO radicals led to the fast production of C₂H₅CHO, CH₃COCH₃, and CH₃CHO. The corresponding species profile highlighted the reaction relevant to ROO and RO radicals (NC₃H₇O + O₂ = C₂H₅CHO + HO₂ and 2 IC₃H₇O₂ = 2 IC₃H₇O + O₂). Rate constants of these reactions were updated, which can potentially improve the performance of the core mechanism under lower temperatures and provide references for model development of larger hydrocarbons.     

Interaction of Wave Trains with Defects

The evolution and transition of planar wave trains propagating through defects(obstacles) in an excitable medium are studied. When the frequency of the planar wave trains is increased, three different dynamical regimes,namely fusion, "V" waves, and spiral waves, are observed in turn and the underlying mechanism is discussed. The dynamics is concerned with the shapes of the defects. Circle, triangle, and rectangle defects with different sizes are considered. The increase of pacing frequency broadens the fan-shaped broken region in the behind of a rectangle defect.The increase of width of a triangle defect leads to breakup of wave trains easier while the change of height shows opposite effect, which is presented in a phase diagram. Dynamical comparison on defects with different shapes indicates that the decrease of the defect width along the propagation of wave trains makes the fan-shaped region and the minimal frequency for breakup of spiral both increased.     

Interaction of phonons with quasistationary states

Decay of the states via this interaction is considered. The line width in ferromagnetic resonance as a function of temperature is calculated in the spin-wave approximation, and the results are compared with experiment.I am indebted to L. N. Ovander for direct!on in this work and for valuable advice.     

Interaction of charged particles with nanotubes

We have studied the interaction of charged particles with single-walled metallic nanotubes by solving Poisson’s equation with appropriate boundary conditions. Numerical results for the energy dispersion relations as a function of the wave vector are presented when the charged particle is inside or outside the nanotube.     

Interaction of transferrin with cefuroxime sodium

ABSTRACT

The interaction between cefuroxime sodium and transferrin in physiological buffer (pH 7.4) was investigated by spectroscopy at 298, 310, and 318?K. The analysis of data indicated that quenching mechanism of the transferrin–cefuroxime sodium system was probably static. The electrostatic force played an important role in the conjugation reaction between transferrin and cefuroxime sodium. The order of magnitude of binding constants (K_a) was 10⁴, and the number of binding site (n) in the binary system was approximately equal to 1. Besides, the values of Hill’s coefficients were lager than 1, which indicated very weakly positive cooperativity in the transferrin–cefuroxime sodium system. The synchronous fluorescence spectra and circular dichroism spectra revealed that the microenvironment and the conformation of transferrin were changed during the binding reaction.     

Interaction of acoustic waves with polycrystals

We analyze theoretically the structure of the field created in a semi-infinite polycrystal by an acoustic wave, coming from an isotropic homogeneous medium and incident normally onto its surface. The elastic anisotropy of the polycrystal is supposed to be small, and the perturbation theory is applied. It is shown that the effective medium approach is not valid. In addition to the transmitted wave propagating in the polycrystal with an effective sound speed, there is one more bulk wave, whose amplitude decreases at a distance of the order of the mean size of the grain from the interface. The structure of the reflected wave is the same as when reflecting from an isotropic solid. However, the relation between the amplitudes of reflected and transmitted waves differs from that in an isotropic solid.     

Interaction of Au nanowires with impurities

We report the results of our first-principles studies of the interaction between an infinite monoatomic gold nanowire and a carbon-monoxide molecule. We show that the gold monoatomic nanowire is capable of absorbing the CO molecule at the distances of about 1.8 ? and forms a bond with the carbon atom. Further, we find that dissociation of the CO molecule as the source of gold nanowire contamination with carbon, which is widely discussed in literature as the possible reason for the striking stability of gold nanowires under stretching, is thermodynamically unfavored.