Andreev reflections in a Bi<Subscript>1.8</Subscript>Pb<Subscript>0.3</Subscript>Sr<Subscript>1.9</Subscript>Ca<Subscript>2</Subscript>Cu<Subscript>3</Subscript>O<Subscript>x</Subscript> break junction

The current-voltage characteristic (CVC) of a break junction made from polycrystalline Bi_1.8Pb_0.3Sr_1.9Ca₂Cu₃O_x is investigated. The experimental CVC has a hysteretic feature that reflects part of the curve with a negative differential resistance. The CVC is discussed within the framework of the Kümmel-Gunsenheimer-Nicolsky theory that takes into account multiple Andreev reflections in superconductor/normalmetal/superconductor junctions.     

Magnetoelectrical effect in layered composites PbZr<Subscript>0.53</Subscript>Ti<Subscript>0.47</Subscript>O<Subscript>3</Subscript>-Mn<Subscript>0.4</Subscript>Zn<Subscript>0.6</Subscript>Fe<Subscript>2</Subscript>O<Subscript>4</Subscript>

The magnetoelectric (ME) effect in two- and three-layered composites made up of polarized ceramic plates of lead zirconate-titanate PbZr_0.53Ti_0.47O₃ (PZT) and manganese-zinc ferrite Mn_0.4Zn_0.6Fe₂O₄ (MZF) has been studied. Dependences of the transverse ME voltage coefficient (α₃₁) on the magnetostrictive layer thickness and the magnetic field intensity and frequency have been established. The mechanical coupling coefficient of the composite plates has been estimated. Results obtained for two-layered PZT-MZF structures have been analyzed using the method of efficient medium parameters.     

Electronic structures of Heusler alloy Co2FeAl1-xSix surface

We have calculated the electronic structures of Co2FeAl1-xSix(101) surface using first-principles method based on the density functional theory. Because of the surface effect, the minority spin band gap at the Fermi level disappears at the surface of bulk Co2FeAl1-xSix. However, beneath the surface, the minority spin gap opens at the Fermi level, which indicates that the electronic structures of Co2FeAl1-xSix(101) be-come close to that of bulk phase. Accordingly, the Co2FeAl1-xSix(101) surface is a composite tri-layer structure that corresponds to the weakening of half-metallic property in Co2FeAl1-xSix films. Even though, the spin polarization of Co2FeAl1-xSix(101) surface is still larger than that of Co2FeAl or Co2FeSi materials, making Co2FeAl1-xSix a promising spintronics material.     

Connectionism;Backpropagation;Structure;Interpretation;Symbolic Logic

A particular backpropagation network, called a network of value units, was trained to detect problem type and validity of a set of logic problems. This network differs from standard networks in using a Gaussian activation function. After training was successfully completed, jittered density plots were computed for each hidden unit, and used to represent the distribution of activations produced in each hidden unit by the entire training set. The density plots revealed a marked banding. Further analysis revealed that almost all of these bands could be assigned featural interpretations, and played an important role in explaining how the network classified input patterns. These results are discussed in the context of other techniques for analyzing network structure, and in the context of other parallel distributed processing architectures.     

Thermodynamic Assessment of PrCl<Subscript>3</Subscript>-CaCl<Subscript>2</Subscript> and NdCl<Subscript>3</Subscript>-CaCl<Subscript>2</Subscript> Systems

By using the CALPHAD technique, an assessment of the binary PrCl₃-CaCl₂ and NdCl₃-CaCl₂ systems have been carried out. From measured phase equilibrium data and experimental integral properties, the PrCl₃-CaCl₂ and NdCl₃-CaCl₂ phase diagrams were optimized and calculated. A set of thermodynamic functions has been optimized based on an interactive computer-assisted analysis. The calculated results by present method agree well with the experimental data.     

Connectionism;Neural Networks;Learning;Ambiguities;Reading

After a brief review of the different types and causes of ambiguous training data and the problems of learning from such data, a class of multi-target models are presented which suggest that neural networks are even better at solving these problems than previously realized. They are able to learn which non-ambiguous subset of a larger ambiguous set of training data best captures any underlying regularities in that data and hence optimize generalization while minimizing the problems of overtraining. It is also shown how the deliberate generation of ambiguous training data can begin to solve some of the longstanding representational problems of mapping time sequences, such as the alignment problem for reading and spelling. The general ideas are illustrated throughout with the well-known problem of tex-to-phoneme conversion, and detailed results of a range of neural network simulations are presented.     

Up-Date of a Thermodynamic Database of the ZrO<Subscript>2</Subscript>-Gd<Subscript>2</Subscript>O<Subscript>3</Subscript>-Y<Subscript>2</Subscript>O<Subscript>3</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> System for TBC Applications

The thermodynamic database of the ZrO₂-Gd₂O₃-Y₂O₃-Al₂O₃ system is up-dated taking into account new data on lattice stabilities of ZrO₂, Gd₂O₃ and Y₂O₃ and heat capacity measurements for the monoclinic phase Gd₄Al₂O₉ and phase with garnet structure Gd₃Al₅O₁₂. New data for the heat capacities of Gd₂Zr₂O₇ (pyrochlore) and GdAlO₃ (perovskite) as well as on the enthalpy of formation of fluorite solid solutions (Zr_1−x Gd _x )O_2−x/2 were found to be in good agreement with calculated results. In comparison with the previous assessment, taking into account new experimental data resulted in a change of the melting character of the Gd₄Al₂O₉ phase from a peritectic one to a congruent one in the Gd₂O₃-Al₂O₃ system. Correspondently, in the ternary system ZrO₂-Gd₂O₃-Al₂O₃, the melting character of the three-phase assemblage Gd₂O₃ (B), Gd₄Al₂O₉ and GdAlO₃ changed from eutectic to transition type U. The T ₀-lines for T/M and F/T diffusionless transformations and driving force of partitioning to equilibrium assemblage T + F were calculated in the ZrO₂-Gd₂O₃-Y₂O₃ system.     

Electrochemical corrosion behaviors of amorphous Co<Subscript>69</Subscript>Fe<Subscript>4.5</Subscript>Ni<Subscript>1.5</Subscript>Si<Subscript>10</Subscript>B<Subscript>15</Subscript> alloy

The corrosion behavior of an amorphous Co₆₉Fe_4.5Ni_1.5Si₁₀B₁₅ alloy ribbon was examined as a function of solution temperature (15 °C to 55 °C) and pH (3 to 11). The results of potentiodynamic polarization tests in H2SO4 solution, NaCl solution, and HCl + NaOH solution at various levels of pH showed that the corrosion resistance for the alloy ribbon significantly deteriorated with increasing temperature and decreasing pH for given conditions. The Co₆₉Fe_4.5Ni_1.5Si₁₀B₁₅ alloy was actively dissolved in solutions at pH 3 to 9 but passivated in a solution at pH 11. By comparison of the corrosion behaviors of Co₆₉Fe_4.5(Nb,Cr,Ni)_1.5Si₁₀B₁₅ alloys in the solution at pH 11, Ni was considered to contribute less in improving the corrosion resistance of the alloy than did Cr and Nb.     

Structure and properties of hydrogen-intercalated YBa<Subscript>2</Subscript>Cu<Subscript>3</Subscript>O<Subscript><Emphasis Type="Italic">y</Emphasis></Subscript>

The effect of hydrogenation at 150 and 200°С on the structure and magnetic susceptibility of YBa₂Cu₃O_y (123) with different hydrogen contents has been studied. Upon the incorporation of hydrogen, the phase transition of the 123 phase into a defect tetragonal 124 phase occurs. In contrast to the transition upon hydration, the phase transition upon hydrogenation takes place only for compounds characterized by high oxygen contents (y > 6.5). Depending on the compound structure and oxygen content, hydrogen atoms can both occupy interstitials in Cu–O planes to form HYBa₂Cu₃O₆ and join with oxygen to form an oxide–hydroxide. In contrast to hydration, upon hydrogenation of YBa₂Cu₃O_y, the substitution of europium for yttrium and alloying with cerium and zirconium oxides do not block the intercalation of hydrogen into the structure of the 123 compound.     

Structure and Inter-Diffusion Coefficients of Liquid Na<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>K<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript> Alloys

Structure and atomic transport properties of liquid Na-K alloys are reported. Inter-diffusion coefficients of liquid Na _x K_1−x , alloys are calculated using scaling law proposed by Samanta et al. following Dzugutov which express the possible relationship between the excess entropy and diffusion coefficient. The interatomic interactions are described from the individual version of the electron-ion potential proposed by Fiolhais et al. The partial pair distribution functions and structure factors are calculated from the solution of Ornstein-Zernike integral equation with Rogers-Young closure. The evaluation with the composition of static structure and inter-diffusion properties are discussed.     

Magnetic properties of Ni<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Co<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript> nanoparticles in carbon nanotubes

The interlayer coupling in an Fe/Cr/Fe layer system with wedge-type chromium spacers was investigated as a function of the chromium-layer thickness and temperature using Kerr magnetometry. The system with a moderate roughness demonstrates an interlayer coupling that can be well described in the framework of the biquadratic coupling model. The smoother sample shows interlayer coupling that can be described using both the biquadratic coupling and the proximity magnetism model proposed by Slonczewski.     

Enhancement of room-temperature magnetoresistance in La<Subscript>0.6</Subscript>Dy<Subscript>0.1</Subscript>Sr<Subscript>0.3</Subscript>MnO<Subscript>3</Subscript>/Ag<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>

The samples of La0.6Dy0.1Sr0.3MnO3/(Ag2O)x/2(x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, 0.20, 0.25, and 0.30) were prepared by using the solid-state reaction method.Their magnetic property, transport behavior, transport mechanism and magnetoresistance effect were studied through the measurements of magnetization-temperature(M-T) curves, ρ-T curves and the fitting of ρ-T curves.The results indicated that Ag could take part in the reaction when the doping amount is small.However, when the doping amount is compar...     

AgNO<Subscript>3</Subscript>-LiNO<Subscript>3</Subscript>-RbNO<Subscript>3</Subscript> phase diagram

The ternary system of silver, lithium, and rubidium nitrates has been studied. Five vertical sections were established: AgNO₃-Li_0.5Rb_0.5NO₃; Li_0.5Rb_0.5NO₃-Ag_0.5Rb_0.5NO₃; 20 mol% AgNO₃; 80 mol% AgNO₃; and the section 5 mol% LiNO₃. Ten invariant points were found. A schematic representation of ternary equilibria is given. The three binary systems are also reported.     

Preparation and characterization of nanostructured Bi<Subscript>2</Subscript>Se<Subscript>3</Subscript> and Sn<Subscript>0.5</Subscript>-Bi<Subscript>2</Subscript>Se<Subscript>3</Subscript>

Nanostructured Bi₂Se₃ and Sn_0.5-Bi₂Se₃ were successfully synthesized by hydrothermal coreduction from SnCl₂·H₂O and the oxides of Bi and Se. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and field emission scanning electron microscope (FESEM). Bi₂Se₃ powders obtained at 180°C and 150°C consist of hexagonal flakes of 50–150 nm in side length and nanorods of 30–100 nm in diameter and more than 1 μm in length. The product obtained at 120°C is composed of thin irregular nanosheets with a size of 100–200 nm and several nanometers in thickness. The major phase of Sn_0.5-Bi₂Se₃ synthesized at 180°C is similar to that of Bi₂Se₃. Sn_0.5-Bi₂Se₃ powders are primarily nanorod structures, but small amount of powders demonstrate irregular morphologies.     

TiAl合金表面阴极微弧沉积Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;陶瓷涂层的生长过程与相组成

目的：利用阴极微弧沉积技术在预处理后的TiAl合金表面制备了Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;陶瓷涂层,研究了涂层的生长过程和相组成。方法：采用电子扫描电镜(SEM、EDS)、电子透射电镜(TEM)、X射线衍射(XRD)等方法,对Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;涂层的生长过程中的微观形貌、组织成分以及晶体结构的演变进行了研究与分析。结果：TiAl合金表面阴极微弧沉积过程中,在阴极表面发生非晶态Al(OH)&lt;sub&gt;3&lt;/sub&gt;的吸附、脱水烧结形成Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;陶瓷涂层的沉积。结论：Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;涂层生长分前期Ⅰ、中期Ⅱ和后期Ⅲ三个阶段,前期起弧阻挡层被击穿,涂层生长较慢、组织致密且与基体结合良好;反应中期涂层生长较快,Al(OH)&lt;sub&gt;3&lt;/sub&gt;不断吸附和脱水烧结,涂层结晶度提高;反应后期涂层生长速度变缓,表层组织疏松、多孔,相组成为87.5 %的α–Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;和12.5 %的γ–Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;。     

Fe₇₃Si₁₅Nb₃B₈Cu₁铁芯薄带的热处理工艺研究

本文对用Finemet型Fe73Si15Nb3B8Cu1快淬薄带制备的铁芯增加预退火处理,再在540 oC晶化退火处理得到退火铁芯。结果表明,随着预退火温度提高,预退火的薄带及再经晶化退火的薄带的韧性均逐渐降低,预退火后非晶薄带的第一晶化温度变化不大,而第二晶化峰值温度向高温方向偏移,预退火扩大了非晶薄带晶化退火的温度范围,有利于获得性能更加稳定的非晶纳米晶薄带;增加预退火处理的薄带的晶粒尺寸比直接晶化退火薄带的晶粒分布更均匀,其中在450 oC预退火的薄带经晶化退火后,晶粒尺寸在8~15 nm之间。增加预退火的铁芯样品,其振幅磁导率和铁损较直接退火的均有明显改善,其中经450 oC预退火的铁芯具有最大的振幅磁导率（μa=8.6×104, f=10 kHz）和最小的交流铁损（P0.5/10k=8.7 W/kg）,分别较直接退火的铁芯升高了16.0%,下降了17.1%。     

Phase Equilibria in the Tl<Subscript>2</Subscript>Te-Tl<Subscript>5</Subscript>Te<Subscript>3</Subscript>-Tl<Subscript>9</Subscript>TmTe<Subscript>6</Subscript> Section of the Tl-Tm-Te System

Phase equilibria in the Tl₂Te-Tl₅Te₃-Tl₉TmTe₆ section of the Tl-Tm-Te ternary system were experimentally studied by using the powder x-ray diffraction technique, differential thermal analysis, as well as microhardness measurements applied to equilibrated alloys. Several isopleth sections and isothermal section at 680 K, as well as projections of the liquidus and solidus surfaces, were constructed. The Tl₅Te₃-Tl₉TmTe₆ section is characterized by the formation of continuous series of solid solutions (δ-phase) with Tl₅Te₃ tetragonal structure, which penetrate deep into the concentration triangle and occupy more than 90% of its area. A narrow area of solid solutions (α-phase) based on Tl₂Te was detected.     

Dilatometric analysis of the process of the nanocrystallization of Fe<Subscript>72.5</Subscript>Cu<Subscript>1</Subscript>Nb<Subscript>2</Subscript>Mo<Subscript>1.5</Subscript>Si<Subscript>14</Subscript>B<Subscript>9</Subscript> soft magnetic alloy

The process of the nanocrystallization of magnetically soft Fe_72.5Cu₁Nb₂Mo_1.5Si₁₄B₉ alloy has been studied using dilatometry and thermomagnetic analysis, together with structural investigations. It has been shown that the amount of nanocrystalline phase precipitated upon heating of the amorphous precursor is in good agreement with a shortening of the ribbon length in the course of crystallization. Thermal expansion at the different stages of heating and cooling depends on the structural and phase states, as well as on the magnetic state of the alloy. The numerical value of the coefficient of linear thermal expansion decreases with an increase in the fraction of the ferromagnetic crystalline phase.     

Structure and principal electrophysical properties of Ge<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>-Si<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> thin films

In the process of thermal treatment of deposited Ge_0.85Si_0.15 films, a number of peculiarities were found related to the character of their conductivity. The films of Ge_0.85Si_0.15 solid solutions are rather resistant to thermal quenching. It was shown experimentally that irradiation with electrons under an accelerating voltage enhances the crystallization in the films and lowers their electric conductivity.     

New ternary compound La<Subscript>8</Subscript>Al<Subscript>13</Subscript>Sn<Subscript>3</Subscript>

A new ternary compound La₈Al₁₃Sn₃ was synthesized and studied by means of X-ray powder diffraction technique. The compound La₈Al₁₃Sn₃ crystallizes in a hexagonal AlB₂-type structure with space group P6/mmm (No. 191) and the lattice parameters a = 0.44919(1) nm and c = 0.43835(1) nm. The Smith and Snyder figure of merit for index, F _N , is F ₃₀ = 197.3(30). The Rietveld refinement for the crystal structure of the compound was carried out successfully. The liability R-factors of Rietveld refinement are R _p = 0.114 and R _wp = 0.148. The compound La₈Al₁₃Sn₃ decomposes into LaAl₂ with cubic structure and space group Fd $ \bar 3 $ \bar 3 m (227), LaAl₃ with hexagonal structure and space group P6₃/mmc (194), and Sn at 720°C.