Are 1/2 and 0.5 represented in the same way?

Adults' processing of unit and decimal fractions was investigated using the numerical comparison task. When unit fractions were compared to integers, the pattern of distance effect found suggests that they were perceived to be on the same mental number line as integers; however, their representation was undifferentiated, as they were perceived to have the same magnitude. This was found both with simultaneous and with sequential presentation. When decimal fractions were compared to integers, the pattern of results suggests that they were also represented on the same mental number line with integers, but their representation was differentiated. Possible explanations for the different patterns found for unit and decimal fractions are discussed. Moreover, compatibility between the magnitude of the whole fraction and that of its components relative to the compared integer affected performance in the case of decimal fractions and unit fractions presented simultaneously, but not in the case of unit fractions presented sequentially. This suggests that sequential processing reduces the components representation of fractions and the whole number bias.     

Determination of glass-forming ability of Ge1− x Sn x Se2.5 (0 ≤ x ≤ 0.5) alloys using differential scanning calorimetry

The glass-forming ability of Ge_{1? x} Sn _x Se_2.5 (0 ≤ x ≤ 0.5) alloys was studied using differential scanning calorimetry. Samples were scanned at different heating rates under non-isothermal conditions. Various simple quantitative methods were employed to assess the stability of the glassy materials in the above-mentioned system. All of these methods are based on characteristic temperatures, such as the glass-transition temperature, T _g, the onset-of-crystallization temperature, T _c, and the peak crystallization temperature, T _p. A crystallization rate factor, K, has also been used as a measure of the thermal stability of the glasses. It was found that Ge_0.7Sn_0.3Se_2.5 was the least stable among all the samples.     

Photoinduced and thermally induced bleaching of amorphous Ge─S films

Abstract

The photoinduced changes of the optical properties of Ge₂₇S₇₃ thin films have been examined using visible and infrared spectroscopy. It was found that illumination of the virgin thin film in vacuum is accompanied by a blue shift of the optical gap and by an increase of the Ge─S bond density. If the film is illuminated in air, the blue shift of the gap is observed too, but the density of Ge─S bonds decreases and new extrinsic absorption bands around 820 and 695 cm^?1 appear in the spectrum, indicating most probably the presence of Ge─O bonds. It is supposed that in the former case the photoinduced changes are most probably intrinsic (decreases of the randomness of the film structure), while in the second case the photoinduced bleaching is accompanied by photoinduced oxidation of the film.     

Structural modification of Ge–Se amorphous films with the addition of Sb

Extended X-ray absorption fine-structure (EXAFS) measurements were undertaken to understand the structural modification of amorphous Ge–Se films that occurs with the addition of Sb. We found that Ge–Ge bonds exist along with Ge–Se bonds in Ge-rich Ge–Se films. These bonds disappear with increasing Se content, to the extent that Ge–Se bonds predominate in stoichiometric GeSe₂ films. When Ge is replaced by Sb, stable Sb–Se bonds are formed; concurrently, the proportion of Ge–Ge bonds is decreased at the expense of Ge–Se bonds. As a result, GeSbSe glasses have a more stable and stronger network structure.     

Crystal growth velocity in deeply undercooled Ni–Si alloys

The crystal growth velocity of Ni₉₅Si₅ and Ni₉₀Si₁₀ alloys as a function of undercooling is investigated using molecular dynamics simulations. The modified imbedded atom method potential yields the equilibrium liquidus temperatures T _L?≈?1505 and 1387?K for Ni₉₅Si₅ and Ni₉₀Si₁₀ alloys, respectively. From the liquidus temperatures down to the deeply undercooled region, the crystal growth velocities of both the alloys rise to the maximum with increasing undercooling and then drop slowly, whereas the athermal growth process presented in elemental Ni is not observed in Ni–Si alloys. Instead, the undercooling dependence of the growth velocity can be well-described by the diffusion-limited model, furthermore, the activation energy associated with the diffusion from melt to interface increases as the concentration increases from 5 to 10?at.% Si, resulting in the remarkable decrease of growth velocity.     

Structural heterogeneity in a binary Pd–Si metallic glass

A Pd₈₁Si₁₉ bulk metallic glassy rod with a diameter of 4.5 mm was produced by water quenching the fluxed alloy. Despite a negative heat of mixing between Pd and Si elements and very simple components constituting the binary Pd–Si glass-forming system, structural heterogeneity was induced either by slow cooling of a liquid or sub-T_g annealing of glassy ribbons. The sub-T_g annealing experiments evidenced that a more ordered amorphous phase emerged from the original glassy matrix. Our work provides an alternative way to tune the microstructure of metallic glasses by subsequent thermal treatment on an as-prepared single glassy phase.     

Rapid dendritic growth within an undercooled Ni–Cu–Fe–Sn–Ge quinary alloy

A liquid quinary alloy with composition Ni–5%Cu–5%Fe–5%Sn–5%Ge has been prepared from a containerless state by undercooling. Dendritic growth of α-Ni phase took place with a velocity of 28 m s^?1 at the maximum degree of undercooling, which was as high as 405 K (0.24T _L). All of the four solute elements Cu, Fe, Sn and Ge exhibited a significant solute trapping effect during the rapid dendrite growth. Segregation-less solidification is consequently realized when the degree of undercooling is sufficiently large. The lattice constant of α-Ni solid solution phase is found to increase with the amount of multicomponent solute trapping.     

Influence of Cd and Ge on the kinetics of Guinier–Preston zone formation in Cu–Be alloys

The influence of Cd and Ge on the kinetics of Guinier–Preston zone formation has been studied for Cu–2?wt%?Be–0.3?wt%?Cd and Cu–2?wt% Be–0.3wt%?Ge solid solutions. The relative volume fractions of these Guinier–Preston (GP) zones are determined for different times of ageing at 473?K by a method based on microhardness measurements. Cd atoms in Cu–Be–Cd accelerate GP zone formation. This is due to the supersaturation of Cd atoms in Cu and their strong binding energy with vacancies. In contrast, the Ge atoms do not influence GP zone formation in Cu–Be–Ge. The binding energies between the two solute atoms and a vacancy, and the concentration of the quenched-in vacancies bound to the solute atoms, are calculated using the Hasiguti formula and the Kimura equation.     

Microstructural features of phase transformation in a binary Pd–Si metallic glass

Glassy ribbons of Pd–Si alloys were prepared by a combination of melt spinning and flux treatment. The crystallization behaviour of a Pd₈₁Si₁₉ glassy alloy was studied through isothermal annealing at temperatures ranging lower than the glass-transition temperature T _g to around the onset of crystallization. The evolution of microstructures arising from isothermal annealing was investigated by X-ray diffraction (XRD) and (high-resolution) transmission electron microscopy ((HR)TEM). XRD spectra showed that, after the sample was annealed at a sub-T _g temperature, its first diffraction peak was split into two overlapping broad peaks. TEM analysis revealed the formation of a spherical, particle-like glassy phase embedded in the glassy matrix together with a finely connected network morphology within both. Combining these observations with compositional analysis suggested that phase separation had taken place during sub-T _g annealing. When the glassy alloy was annealed at temperatures higher than T _g, nanocrystalline structures, composed of Pd₃Si and Pd phases plus a Pd₉Si₂ phase with a lamellar structure, was formed.     

Increasing toughness by promoting discontinuous precipitation in Cu–Ni–Si alloys

The influence of precipitation morphology, including continuous precipitation (CP) and discontinuous precipitation (DP), on the mechanical behaviour of Cu–Ni–Si alloys was studied. The Cu–6Ni–1.5Si (in wt%) alloy was solution heat treated at 980 °C for 2 h and aged at 500 °C for 0.5 and 3 h to produce CP and DP structures. The DP specimen showed an abnormal increase in tensile ductility with increasing strain rate, unlike the CP counterpart. The impact toughness of the DP specimen was 1.6 times greater than that of CP specimen. The fracture mode in DP specimen was mostly dimpled rupture, while the mixed mode of cleavage fracture and dimpled rupture was noted on the CP specimen.     

Dynamics of upconversion photoluminescence in Ge–Ga–S: Er3+: application of quadrature frequency resolved spectroscopy

Quadrature frequency resolved spectroscopy (QFRS) on green (~550 nm) upconversion photoluminescence (UCPL) of Ge–Ga–S: Er³⁺ glasses pumped at 975 nm revealed double-peaked spectra with long lifetime τ₁ ranging from 0.2 to 2 ms and short lifetime τ₂ ≈ several tens of μs. The results are analysed in terms of the transfer function derived by linearizing rate equations for a three-level model. The τ₁ component is attributed to the relaxation at the intermediate level ⁴I_11/2 of Er³⁺ ions and the τ₂ component, to that at the upper ⁴S_3/2 manifold. The dominance of energy transfer upconversion over excited state absorption in the UCPL manifest itself as a greater dependence of τ₁ on the pump power and a lower ratio of the components of τ₂ to τ₁ in the QFRS spectra of a heavily Er-doped sample.     

Energetic effects of dopants on the eutectoid decomposition of Nb–Si in situ composites

The influences of doping elements (Ti, Zr, Hf, V, Ta, Cr, Mo, W and Al) on the heats of formation of Nb, Nb₅Si₃ and Nb₃Si have been studied using first-principles pseudopotential plane-wave method based on density functional theory. Site preferences of dopants in Nb₅Si₃ and Nb₃Si intermetallics are first determined by comparing the heats of formation of the systems with different site occupations of the doping atoms. The partitionings of dopants between the equilibrium phases Nb and Nb₅Si₃ of Nb–Si in situ composites are then discussed and compared with experimental results. Phase partitioning behaviours of the alloying elements are found to depend strongly on the number of their valence electrons. By calculating the enthalpy of reaction regarding the eutectoid decomposition of Nb₃Si phase, we conclude that Ta is a Nb₃Si stabiliser while other dopants destabilise Nb₃Si at the investigated concentration.     

Kolb学习风格与中国大学生英语/i/-/I/发音的关系

以中国大学生为对象, 在对其英语/i/-/&;#618;/发音进行声学分析的基础上, 从Kolb经验学习模式入手, 结合其他相关学习者因素, 探讨学习风格与英语/i/-/&;#618;/发音的关系。结果显示, 中国学生发音表现个体差异较大, 其发音水平与学习风格紧密相关：吸收型和发散型学习者表现较好, 集中型学习者较差, 适应型学习者最差。另外, 中国学生发音表现与其英语使用和练习量也有显著正相关, 但与英语学习起始年龄和英语教育年限等其他因素都无直接联系。     

/n/-/l/音位合并现象的神经机制：来自MMN的证据

采用ERP技术,比较音位合并者与非音位合并者辨别合并音位/n/-/l/的脑电和行为反应。结果发现,非音位合并者在注意前阶段展现了显著的MMN;而音位合并者没有展现MMN,但在晚期展现了一个显著的负波。行为实验发现,相比于音位合并者,非音位合并者在分辨/n/-/l/时正确率更高,反应时更短。这些结果表明：两组被试区分/n/-/l/的能力在早期自动加工阶段就已经有了显著的差异。方言经验可能降低了音位合并者在听觉感觉加工阶段检测合并音位差异的敏感度。     

“Si fallor,ergo Sum”──奥古斯丁对希腊哲学的批判和改造

奥古斯丁在西方哲学史上是一位颇具个性的思想家。然而,长期以来学术界对他并没有给予足够重视和深入探讨。本文从他的一个重要命题“我错误,所以我存在”入手,着重分析奥古斯丁对希腊哲学的批判和改造,进而指出这种批判所独具的深刻意义。一、希腊理智主义的局限性应当指出,奥古斯丁这一命题的提出有其认识背景。首先与希腊理智主义独断论有关。在希腊哲学,尤其是亚里土多德以前的哲学传统中,理智主义独断论居主流地位。自巴门尼德和赫拉克利特以来,先哲们对人的理智能力寄予厚望。无论是理智主义还是感觉主义,都以认识的确定性为…     

Specific heat,enthalpy, and density of undercooled liquid Fe–Si–Sn alloy

The specific heat of liquid Fe₉₀Si_6.95Sn_3.05 alloy has been investigated by electromagnetic levitation drop calorimetery in the temperature range of 1390–2140 K. The enthalpy of this liquid alloy increases linearly with the rise of temperature. Furthermore, the enthalpy obtained from molecular dynamics calculation shows a similar trend to the experimental results in a broader temperature range of 1000–2200 K. The calculated specific heat is 39.7 J mol^?1 K^?1, which agrees well with the experimental result of 39.9 J mol^?1 K^?1. The density of this liquid alloy decreases as a quadratic function of temperature.