Adsorption effect in non-reaction wetting: In–Ti on CaF2

The experiments show that the alloying liquid In with only (0.1–0.5) at% Ti dramatically reduces the equilibrium contact angle Θ _∞ formed by In on the surface of CaF₂. The aim of this paper is to clarify whether this practically important and conceptually challenging effect can be explained solely by Ti adsorption at the F-terminated solid–liquid interface without resorting to any other Ti-induced effect. The combination of ab initio calculations and regular solution approximation was proposed for finding the binding energy, ΔE _Ti of Ti adatom with the interface “CaF₂/liquid solutions In–Ti.” With thus obtained ΔE _Ti=1.16 eV, we calculated from the Shishkovsky isotherm the reduction in the solid–liquid interface energy, Δγ _SL induced by Ti adsorption from liquid In with various Ti concentration, C. It was found that Δγ _SL(C) dependence demonstrated close inverse correspondence with Θ _∞(C) and that the theory fitted very well all available experimental data on the concentration and temperature dependence of Δγ _SL. It was concluded that the Ti adsorption effect is large enough to account for the observed wetting improvement. The proposed multiscale modeling approach to the role of adsorption in wetting can be applied also to other nonreactive systems “liquid metal–ceramics” where the substrate determines the surface density of the adsorption sites for the active element.     

Use of surface acoustic waves for analysis of gases and surface processes induced by them

An analytical expression for the magnitude of the “response” of surface acoustic waves (SAWs) to gases is obtained. It is tested experimentally. The main features of the detection of gases by means of SAWs are predicted theoretically and confirmed experimentally. The SAWs in coated and uncoated gas sensors are compared. A technique for using SAWs to determine the relative changes in the density (Δρ/ρ) and the elastic moduli (ΔC ₁₁/C ₁₁ and ΔC ₄₄/C ₄₄) of films upon the adsorption (desorption) of gases is proposed. The possibility of using this technique to analyze adsorption and desorption processes is demonstrated. The adsorption properties of polycrystalline, thermally deposited palladium films before and after low-temperature vacuum annealing, as well as unannealed Pd and Pd:Ni films, are compared. The prospects of using SAWs to detect gases and to study surface processes induced by them are discussed. Zh. Tekh. Fiz. 68, 73–81 (February 1998)     

Preparation of P(AN-MMA) gel electrolyte for Li-ion batteries

Phase inversion technique was used to prepare poly(acrylonitrile-methyl methacrylate) [P(AN-MMA)]-based microporous gel electrolyte with addition of SiO₂ via in-situ composition for Li-ion batteries. The P(AN-MMA) was synthesized by emulsion polymerization and was dissolved into N,N-dimethylformamide (DMF) to form a uniform solution, while tetraethyl orthosilicate (TEOS) was added into the solution and was hydrolyzed by catalysis of alkali ammonia solution to form SiO₂. Then the solution was cast onto a glass plate using a doctor blade and exposed to humidified atmosphere produced by ultrasonic humidifier, followed by washing, rinsing, and drying, successively. The gel electrolyte was obtained by putting the P(AN-MMA) microporous membrane in a liquid electrolyte. The gelled microporous membrane sucked with 755 wt% of liquid electrolyte vs the dried membrane. It had a porosity of 70%, about 1∼5 μm of pores, and presented an ionic conductivity of 0.94 × 10⁻³ S/cm at room temperature. Electrochemical stability window of the porous gel polymer electrolyte was determined by running a linear sweep voltammetry. The decomposition voltage of the polymer electrolyte exceeds 4.5 V vs Li. The coin test cell with the microporous gel electrolyte showed a good cycling performance. The discharge capacity retention was above 87% at 0.1 C for 45 cycles.     

Values of adsorption and surface concentrations of the components in Na-K-Cs alloys

The values of adsorption Γ _i ^(N) and surface concentration X _i ^ω of all the components in alloys of the Na-K-Cs system were determined. The adsorption of cesium Γ_Cs^(N) was found to be > 0, while that for sodium Γ_Na^(N) was < 0 in all ternary alloys. The adsorption of potassium was found to undergo inversion when passing from Γ_K^(N) > 0 in ternary alloys (the ratios being X _Na: X _Cs > 14.4 and X _Cs < 6.5 at %) to the negative value of adsorption Γ_K^(N) in the alloys with X _Na: X _Cs < 14.4 and any cesium concentrations. Using the Na-K-Cs system, it was demonstrated for the first time that conditions ΣΓ _i ^(N) = 0 and ΣX _i ^ω = 1 and are fulfilled in ternary alloys.     

Adsorption and thermodynamics studies of U(VI) by composite adsorbent in a batch system

The adsorption of U(VI) from aqueous solutions onto composite adsorbent (algistar) has been studied using a batch adsorber. The parameters that affect the U(VI) sorption, such as contact time, solution pH, initial U(VI) concentration, and temperature, have been investigated and optimized conditions determined. Equilibrium isotherm studies were used to evaluate the maximum sorption capacity of composite adsorbent, and experimental results showed this to be 43.10 mg/g. The adsorption patterns of metal ions on composite adsorbent followed the Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherms. The Freundlich, Langmuir, and D–R models have been applied, and the data correlate well with Langmuir model, and that the sorption is physical in nature (the sorption energy E _ads = 12.90 kJ/mol). Thermodynamic parameters (∆H _ads^o = −41.08 kJ/mol, ∆S _ads^o = −68.00 J/mol K, ∆G _ads (298.15 K) = −20.81 kJ/mol) showed the exothermic heat of adsorption and the feasibility of the process. The results suggested that the composite adsorbent is suitable as a sorbent material for recovery and biosorption/adsorption of uranium ions from aqueous solutions.     

Intercepts of the momentum correlation functions in the $ \mu$ -Bose gas model and their asymptotics

The so-called μ-deformed oscillator (or μ-oscillator) introduced by A. Jannussis, though it possesses rather exotic properties with respect to other better known deformed oscillator models, also has a good potential for diverse physical applications. In this paper, the corresponding μ-Bose gas model based on μ-oscillators is developed. Within this model, the intercepts l⁽²⁾ \lambda^{{(2)}}_{}(K) and l⁽³⁾ \lambda^{{(3)}}_{}(K) of two- and three-particle momentum correlation functions are calculated with the goal of possible application for modeling the non-Bose-type behavior of the intercepts of two- and three-pion correlations, observed in the experiments on relativistic heavy-ion collisions. In the derivation of intercepts, a fixed order of approximation in the deformation parameter μ is assumed. For the asymptotics of the intercepts l⁽²⁾ \lambda^{{(2)}}_{}(K) and l⁽³⁾ \lambda^{{(3)}}_{}(K) , we derive exact analytical formulas. The results for l⁽²⁾ \lambda^{{(2)}}_{}(K) are compared with experimental data, and with earlier known results drawn using other deformed Bose gas models.     

Classes on Compactifications of the Moduli Space of Curves Through Solutions to the Quantum Master Equation

In this paper we describe a construction which produces classes in compactifications of the moduli space of curves. This construction extends a construction of Kontsevich which produces classes in the open moduli space from the initial data of a cyclic A _∞-algebra. The initial data for our construction are what we call a ‘quantum A _∞-algebra’, which arises as a type of deformation of a cyclic A _∞-algebra. The deformation theory for these structures is described explicitly. We construct a family of examples of quantum A _∞-algebras which extend a family of cyclic A _∞-algebras, introduced by Kontsevich, which are known to produce all the kappa classes using his construction.      

Elastic shape memory effect in In-Pb alloys in the temperature range 0.48–180 K

Pseudoelasticity caused by pseudotwinning in short-range ordered In-Pb alloys (6, 8 and 11.6 at. % Pb) is studied in the temperature range 0.48–180 K. The mechanical hysteresis parameters, namely, the thermodynamic stress τ _T which provides the reversibility of plastic deformation and the frictional stress τ _f which characterizes the resistance offered by crystal lattice and its defects to twin boundaries motion are estimated. It is found that athermal processes determine the reversible deformation: the mechanical parameters τ _T and τ _f do not depend on temperature and strain rate. The stress τ _T increases and the stress τ _f decreases with increasing Pb content. One of the main conditions of the exhibition of superelasticity is the fulfillment of the inequality τ _T >τ _f .     

On twist quantizations of <Emphasis Type="Italic">D</Emphasis> = 4 Lorentz and Poincare algebras

We use the decomposition of o(3, 1) = sl(2; ℂ)₁ ⊕sl(2; ℂ)₂ in order to describe nonstandard quantum deformation of o(3, 1) linked with Jordanian deformation of sl(2; ℂ). Using the twist quantization technique, we obtain the deformed coproducts and antipodes, which can be expressed in terms of real physical Lorentz generators. We describe the extension of the considered deformation of D = 4 Lorentz algebra to the twist deformation of D = 4 Poincare algebra with dimensionless deformation parameter. Presented at the International Colloquium “Integrable Systems and Quantum Symmetries”, Prague, 16–18 June 2005.     

Influence of impurities on the low-temperature deformation of nanocrystalline copper

The influence of ZrO₂ particles on the low-temperature deformation of nanocrystalline copper produced by strong plastic deformation is investigated using equichannel angular pressing. A comparison is made between the deformation characteristics in tension and compression in the temperature range 4.2–400 K, measured for copper and the composite Cu:0.3 vol. % ZrO₂. It is shown that within 4.2–200 K the yield point σ _sm of the composite is higher than that for copper, attaining 680 MPa at 4.2 K, then the yield points are close in value up to room temperature, and diverge again as the temperature is raised. Possible causes of the dissimilar influence of an impurity on the strength and plasticity characteristics of nanocrystalline copper in various temperature intervals are discussed. Fiz. Tverd. Tela (St. Petersburg) 40, 1639–1641 (September 1998)     

Gels at interfaces

We discuss the adsorption of polymer gels on flat surfaces. Even in cases of complete wetting where the spreading power S is positive and where an equivalent liquid would spread, the elastic stresses due to the gel deformation upon adsorption oppose the spreading. The competition between elasticity characterized by the bulk shear modulus G and capillarity characterized by the spreading power S defines a typical length scale ℓ = S/G for the deformation in the gel. For loose gels ℓ can be of the order of 1 μm. Macroscopic gels larger than ℓ deform only at their edges over a region of size ℓ. Microscopic gels smaller than ℓ show a finite deformation despite the elastic stresses. The elastic stresses limit the spreading of the polymer, but solvent can be sucked out of a swollen gel by wetting the surface. The thin solvent film can extend rather far from the gel edge and carry solvent. We calculate the kinetics of the solvent film formation and of the solvent transfer from a more swollen gel to a less swollen gel. Received 16 July 2001     

Quadrupole moment measurement of the highly deformed πg 9/2⊗νh 11/2 band in 130Pr

The quadrupole moment for the πg _9/2⊗νh _11/2 band in the ^130>Pr nucleus has been measured using the Doppler-shift attenuation method. A centroid shift analysis was carried out and a value of Q₀=6.1±0.4 eb, corresponding to an axial prolate deformation of β₂=0.35(3), has been determined. This is the first direct experimental confirmation of the deformation-driving character of the πg _9/2 orbital in an odd-odd nucleus in the A≃135 superdeformed region. Received: 23 April 1998     

Determination of Bioactive Matter by Affinity Adsorption Solid Substrate–Room Temperature Phosphorimetry Based on Lectin Labeled with Self-ordered Ring of Eosin Y

A new phosphorescent labeling reagent named self-ordered ring (ESOR) of eosin Y (E) was developed. And the application of the determination of bioactive matter by affinity adsorption solid substrate–room temperature phosphorimetry (AA-SS-RTP) based on ESOR labeling lectin was studied. Results showed that pink and homogeneous ESOR could be formed by E on polyamide membrane (PAM) in the presence of cetyltrimethylammonium bromide (CTAB) and ammonia water. ESOR could emit strong and stable room temperature phosphorescence (RTP) signal of E in the presence of heavy atom perturber. Specific affinity adsorption (AA) reactions could be carried out between the products of concanavalin agglutinin (Con A), triticum vulgaris lectin (WGA) labeled with ESOR and alpha-fetoprotein variant (AFP-V), alkaline phosphatase (ALP), glucose (G), respectively. Not only did the products of the affinity adsorption reactions preserve good RTP characteristic of E, but also the ΔI _p (ΔI _p = I _p2 − I _p1, I _p1 is the RTP intensity of blank reagent, I _p2 is the RTP intensity of sample) of these products was proportional to the content of AFP-V, ALP and G, respectively. According to the facts above, a new method of AA-SS-RTP for the determination of AFP-V, ALP and G was established, based on ESOR labeling lectin. Detection limits (LD) of this method were 0.040 fg spot⁻¹ for AFP-V, 0.045 fg spot⁻¹ for ALP and 0.090 fg spot⁻¹ for G. And it has been successfully applied to the determination of AFP-V in human serum as well as the survey and forecast of human diseases. This method had high sensitivity, good repeatability, long RTP lifetime and little background interference with at the long wavelength area. Meanwhile, the mechanism for the determination of trace AFP-V by AA-SS-RTP based on Con A labeled with ESOR was also discussed.     

Estimation of the deformation-potential constant for <Emphasis Type="Italic">p</Emphasis>-type isotropic polycrystalline silicon through the deformation potential of a <Emphasis Type="Italic">p</Emphasis>-type silicon single crystal

A method of calculating the effective deformation-potential constant E ₁ for holes and longitudinal acoustic phonons in isotropic polycrystalline silicon is suggested. The deformation-potential constant E ₁ is estimated through the deformation potentials a, b, and d of the silicon single crystal. The procedure of averaging of the squared modulus of the hole and acoustic phonon interaction Hamiltonian written in the plane wave basis over the polycrystal ensemble provides the basis for calculation of the constant E ₁ . It is demonstrated that for T = 200–600 K, hole concentration p = (5.0–10.0)∙10¹⁹ cm^–3, and crystallite size d = 300–3000 ?, the deformationpotential constant E ₁ is independent of the hole concentration p, temperature T, and crystallite size d.     

A study of deformation-produced deep levels inn-GaAs using deep level transient capacitance spectroscopy

Deformation-produced deep levels, both of electron and hole traps, have been studied using deep level transient capacitance spectroscopy (DLTS) for an undopedn-type GaAs (HB grown) compressed at 440°C. Concentrations of two grown-in electron trap levels (E _c −0.65eV andE _c −0.74eV) and one grown-in hole trap level (E _v +∼0.4eV) increase with plastic deformation, while that of a grown-in electron trap level (E _c −∼0.3eV) decreases in an early stage of deformation. While no new peak appeared in the electron trap DLTS spectrum after plastic deformation, in the hole trap DLTS spectrum a broad spectrum, seemingly composed of many peaks, newly appeared in a middle temperature range, which may be attributed to electronic energy levels of dislocations with various characters.     

Intervalley electron scattering by phonons in (AlAs)1(GaAs)3(001) superlattices

Intervalley electron scattering by phonons in (AlAs)₁(GaAs)₃(001) superlattices is studied using the pseudopotential method and a phenomenological model of the bonding forces. The deformation potentials between the conduction band extrema of the superlattice involving short-and long-wavelength phonons are calculated. It is shown that the mixing of states from the zinc-blende L valleys plays a greater role in intervalley scattering in a superlattice than the Γ-X mixing. In particular, due to L-L mixing, the Γ-X ₃ transitions, analogous to Γ-L transitions in zinc blende, have higher intensities than the analogues of Γ-X transitions (Γ₁-M ₅ and (Γ₁-Γ₃ transitions). The deformation potentials averaged over the scattering channels in the superlattice agree with the corresponding potentials in a solid solution, but all transitions in the superlattice have higher intensities for the lower states.     

Shape-driving effect of the proton 1/2[541] band in 171Ta

High-spin states in ¹⁷¹Ta were populated through the heavy-ion fusion-evaporation reaction ¹⁵⁷Gd (¹⁹F, 5n)¹⁷¹Ta at 105MeV beam energy. Lifetimes of the levels of the πh_9/21/2[541] band have been measured by using the Doppler shift attenuation method. The transition quadrupole moments ( Q_t) and the quadrupole deformation (β₂) have been extracted. Both β₂ and Q_t values decrease slightly with increasing rotational frequency. The average β₂ value of 0.26 is 18% larger than that of the πh_11/2 9/2[514] band. Total Routhian Surface calculations have been performed with the non-axial deformed Woods-Saxon potential and the predicted values of the quadrupole deformation β₂ are in good agreement with that deduced from our lifetime measurement. The shape-driving effect is discussed.     

A convergent star product for linear Poisson structures

An explicit star product ⋆ _α ^Γ on the dual of a general Lie algebra equipped with the linear Poisson bracket is constructed. An equivalence operator between this star product and the Kontsevich star product in [K₁] is given and diverse properties of the star product ⋆ _α ^Γ are studied. It is also proved that the star product ⋆ _α ^Γ provides a convergent deformation quantization in the sense of Rieffel [R₁].     

Variations in the electrical resistivity of La0.67Ca0.33MnO3 films and induced interconversions of ferromagnetic and nonferromagnetic inclusions in their bulk

A significant (∼1.8%) positive unit between the parameters of the crystal lattice is the reason of tetragonal distortion (a _⊥/a _‖ ≈ 1.04) and reduction in the volume of the unit cell of La_0.67Ca_0.33MnO₃ films (15 nm) quasicoherently grown on the (001) surface of a LaAlO₃ substrate. The films consist of single-crystal blocks with the lateral size of 30–50 nm. The atomically smooth LaAlO₃-La_0.67Ca_0.33MnO₃ interphase boundary has no misfit dislocations. At T = 4.2 K, the transformation of nonferromagnetic phase inclusions into ferromagnetic ones in a constant magnetic field H is accompanied by a stable reduction in the electrical resistivity ρ of manganite films with time, so that the curve ρ(t) is well approximated by the relationship ρ(t) ∼ ρ₁(t − t ₀)^1/2, (where t ₀ is the time for establishment of the specified value (μ₀ H = 5 T) of the magnetic field and ρ₁ is a coefficient independent of H). The magnetocrystalline anisotropy due to the elastic deformation of films by the substrate and stratification of electronic phases are the reasons of the distinct hysteresis in the dependences ρ(μ₀ H, T < 100 K) obtained on μ₀ H scanning in the sequence 5 T → 0 → −5 T → 0 → 5 T. At T = 50 K and μ₀ H = 0.4 T, the magnetoresistance MR = 100% [ρ(μ₀ H) − ρ(μ₀ H = 0)]/ρ(μ₀ H = 0) of LCMO films attains 150%.     

Effect of infrared radiation on the plasticity of solid hydrogen

This paper reports on the first results obtained from the investigation of the effect of IR radiation on the low-temperature (1.8 ≤ T ≤ 4.2 K) plasticity of solid hydrogen. It has been found that, when the samples are exposed to IR radiation, a drastic increment Δɛ_IR of the elongation per unit length ɛ (which was preliminarily achieved under a continuously applied mechanical stress σ = const) occurs without an increase in the temperature of the samples. It has been revealed that the effect observed both in the case of normal hydrogen (n-H₂, 75% o-H₂) and in the case of parahydrogen (p-H₂, ∼0.2% o-H₂) only for a sufficiently high power of the IR radiation source has a threshold character. The reverse deformation of solid hydrogen is observed after the irradiation with a flux of IR photons is completed: the quantity ɛ rapidly decreases to values provided only by the applied load. The appearance of jumps in the increment of deformation Δɛ_IR ⁱ is interpreted as a consequence of the existence of the fundamental IR absorption band for solid hydrogens. It has been established that, depending on the time t of exposure of the samples to IR radiation, the change in the quantity Δɛ_IR ⁱ (t) obeys the logarithmic law, which is characteristic of the dislocation creep and observed in the case of unirradiated hydrogen. It has also been found that, under multiple relatively long-term exposure to IR radiation, the constant α of the logarithmic creep of n-H₂ abruptly decreases, whereas the strength of both the n-H₂ and p-H₂ samples increases significantly, which indicates their explicit hardening (instead of the expected “superplastic” behavior due to the exposure to IR irradiation).