Surface tension of substantially undercooled liquid Ti–Al alloy

It is usually difficult to undercool Ti–Al alloys on account of their high reactivity in the liquid state. This results in a serious scarcity of information on their thermophysical properties in the metastable state. Here, we report on the surface tension of a liquid Ti–Al alloy under high undercooling condition. By using the electromagnetic levitation technique, a maximum undercooling of 324 K (0.19 T _L) was achieved for liquid Ti-51 at.% Al alloy. The surface tension of this alloy, which was determined over a broad temperature range 1429–2040 K, increases linearly with the enhancement of undercooling. The experimental value of the surface tension at the liquidus temperature of 1753 K is 1.094 N m^?1 and its temperature coefficient is ?1.422 × 10^?4 N m^?1 K^?1. The viscosity, solute diffusion coefficient and Marangoni number of this liquid Ti–Al alloy are also derived from the measured surface tension.     

Surface tension measurement of undercooled liquid Ni-based multicomponent alloys

The surface tensions of liquid ternary Ni–5%Cu–5%Fe, quaternary Ni–5%Cu–5%Fe–5%Sn and quinary Ni–5%Cu–5%Fe–5%Sn–5%Ge alloys were determined as a function of temperature by the electromagnetic levitation oscillating drop method. The maximum undercoolings obtained in the experiments are 272 (0.15T _L), 349 (0.21T _L) and 363?K (0.22T _L), respectively. For all the three alloys, the surface tension decreases linearly with the rise of temperature. The surface tension values are 1.799, 1.546 and 1.357?N/m at their liquidus temperatures of 1719, 1644 and 1641?K. Their temperature coefficients are ?4.972?×?10^–4, ?5.057?×?10^?4 and ?5.385?×?10^?4?N/m/K. It is revealed that Sn and Ge are much more efficient than Cu and Fe in reducing the surface tension of Ni-based alloys. The addition of Sn can significantly enlarge the maximum undercooling at the same experimental condition. The viscosity of the three undercooled liquid alloys was also derived from the surface tension data.     

Effects of surface pre-presentation on symmetry detection on a 3-D bumpy surface

Abstract:  The aim of this study was to investigate the visual detection mechanism of mirror symmetrical dot patterns drawn on a 3-D bumpy surface (i.e., 3-D noisy curved surface). The focus of this investigation was whether symmetry detection on the bumpy surface is associated with structure recovery of the surface. In Experiment 1, we confirmed that the human visual system can distinguish the bumpy surface from a distorted dot pattern on a transparent bumpy surface. In Experiment 2, we required participants to discriminate between a symmetrical pattern on a transparent (non-visible) bumpy surface and an opaque (visible) bumpy surface for the same stimuli as in Experiment 1. Finally, in Experiment 3, we examined the effect of pre-presentation of the opaque bumpy surface on pattern discrimination. The results showed that pre-presentation of the opaque surface facilitated the detection of a diagonal symmetry, but not in the case of the detection of a cardinal symmetry. These results suggested that diagonal symmetry involves the process of surface recovery, whereas cardinal symmetry does not.     

Tonic postural lean after-effects influenced by support surface stability and dynamics

Tonic neuromuscular processes are evident during lean after-effects, which occur after prolonged standing on a fixed ramp. Postural processes underlying lean after-effects were examined here using dynamic surface conditions. Three tilt adaptation conditions were tested with eyes-closed (n = 11). Tilt adaptation conditions involved standing for 120 s on a fixed toes-up ramp (7°) or on a toes-up sinusoidally tilted surface (7° ± 3°), which was followed by 120 s of standing on either a fixed horizontal surface or sway-referenced surface. All participants showed postural after-effects (p < .003). Specifically, standing on a fixed horizontal surface after sine-tilt adaptation, resulted in forward leaning which decayed over 120 s back to baseline. Standing on a sway-referenced surface after tilt-adaptation, initially showed no lean after-effect, however over the course of the trial the center-of-pressure shifted backward (p < .02). This after-effect during sway-reference conditions was also evident in the sway-induced surface tilt, which increased in dorsiflexion (p < .002), rather than decaying back to baseline. Thus, adaptation occurs on a dynamically tilted surface, while reliability of the surface as a stable reference affects the return of the center-of-pressure and surface tilt to baseline. These findings relate to changes in flexor/extensor muscle tonic set-point which also occur following a prolonged voluntary isometric contraction.     

Revisiting the simple view of reading

Background Reading component models such as the Simple View of Reading (SVR; Gough & Tunmer, 1986 ; Hoover & Gough, 1990 ) provide a concise framework for describing the processes and skills involved when readers comprehend texts. According to the Independent Review of the Teaching of Early Reading ( Rose, 2006 ) strong evidence for the SVR comes from Factor Analysis of datasets on different measures of reading showing dissociation between decoding skills and comprehension. To the best of our knowledge, only two such published studies exist to date. Of these, only one of is in English and this explores children between the age of 7 and 10 years. Aims To explore the SVR in English‐speaking children aged 4 and 6 using Factor Analysis. Samples 116 4 ‐year‐olds and 116 6 ‐year‐olds in the US; 103 6 ‐year‐olds in Canada. Methods All children were administered a battery of decoding and comprehension related measures. Results Factor Analysis of the diverse measures undertaken independently by two research teams in different countries demonstrated that listening comprehension and decoding measures loaded as distinct factors in both samples of young English‐speaking children. Conclusions The present findings provide important support for the generality and validity of the SVR framework as a model of reading.     

Shear horizontal surface waves in piezoelectric materials with surface stress

ABSTRACT

The propagation of shear horizontal (SH) surface waves in piezoelectric semi-infinite bodies is investigated theoretically. The surface stress exerting on the boundary is taken into account through surface piezoelectricity theory, and the velocity ranges and existence conditions of such surface waves for both electrically open and shorted cases are derived in detail. Analysis results show that the SH surface waves occurring with surface stress are dispersive in contrast to the classical situation, and the propagation characteristics strongly depend on the relative value of surface elasticity, surface piezoelectricity and surface density.     

两种时空线索条件下表面颜色特征线索对客体保持的作用*

采用客体回溯范式,以客体预览利化效应(object specific previewing benefit, OSPB)作为指标,考察表面特征线索对客体保持的作用。实验1使用双向隧道创建时空线索不明确的条件,研究表面颜色特征线索的作用。实验2使用单向隧道使时空线索明确,研究表面颜色特征线索与时空线索一致、冲突情境下的客体保持。实验1和实验2均出现了OSPB效应,且实验2冲突情境的OSPB效应低于一致情境。研究结果表明在时空线索不明确的条件下,仅凭表面颜色特征线索就能实现客体保持;在时空线索明确的条件下,时空线索是客体保持的主要线索,同时表面颜色特征线索也起一定的作用。     

Role of surface roughness in hysteresis during adhesive elastic contact

In experiments that involve contact with adhesion between two surfaces, as found in atomic force microscopy or nanoindentation, two distinct contact force (P) versus indentation-depth (h) curves are often measured depending on whether the indenter moves towards or away from the sample. The origin of this hysteresis is not well understood and is often attributed to moisture, plasticity or viscoelasticity. Here we report experiments which show that hysteresis can exist in the absence of these effects, and that its magnitude depends on surface roughness. We develop a theoretical model in which the hysteresis appears as the result of a series of surface instabilities, in which the contact area grows or recedes by a finite amount. The model can be used to estimate material properties from contact experiments even when the measured P–h curves are not unique.     

颜色恒常知觉的影响因素探索及其非线性建模

采用计算机仿真技术,研究了照明、表面和背景对颜色恒常的影响,结果表明：照明性质、表面属性以及背景属性均对颜色恒常程度产生显著影响,三者的影响是相互独立的;不同照明性质对颜色恒常程度具有不同影响,中性色照明光下颜色恒常程度较高;人的颜色恒常也依赖于物体的表面属性,对不同的表面进行匹配时,表现出了颜色恒常程度的较大波动;相同背景属性较不同背景属性具有较高的颜色恒常程度。在实验研究基础上建立了非线性颜色恒常模型,该模型对实验数据进行了很好拟合,具有了一定的符合人认知特点的颜色恒常能力。     

High-resolution in situ electron microscopy of a silicon surface modification by molten aluminium at high temperatures

High-resolution in situ heating experiments in a transmission electron microscope have been applied to a study of the surface modification of Si by molten Al in a vacuum of 1 10^-5 Pa. Transformation from an atomically rough to an atomically flat surface was induced by wetting of molten Al atoms. Si {110}, {112}, {115} and {773} surfaces show sawtooth-like structures composed of nanofacets. It is concluded that molten Al atoms remove a native amorphous oxide layer which existed on the original Si surface, making the surface 'clean' even in a non-ultra-high vacuum such as 10^-5Pa.     

Emotional labour strategies and job burnout: A meta-analysis of Chinese employees

Emotional labour strategies have a significant impact on job burnout. However, current research results are controversial and unclear. A meta-analysis was conducted to explore the relationship between emotional labour strategies (surface acting and deep acting) and job burnout. A total of 84 empirical studies that included 28,242 participants were selected. The meta-analysis of the relationships between job burnout and surface acting and deep acting included 84 and 75 independent samples respectively. The results show that surface acting had a positive association (r = 0.25) with job burnout, whereas deep acting (r = −0.27) had a negative association with job burnout. Occupational types and measures of emotional labour strategies moderated the relationship between emotional labour strategies and job burnout, but this relationship was not moderated by measures of job burnout.     

Amorphization under fracture surface in hydrogen-charged and low- temperature tensile-tested austenitic stainless steel

ABSTRACT

The microstructure just below the fracture surface in hydrogen-charged stable austenitic SUS 316L stainless steel, which was subjected to a low strain rate tensile test at ?70°C, was studied by a combination of the focused-ion-beam method and transmission electron microscopy. An amorphous region with a chemical composition almost identical to that of the polycrystalline region was found under the lath-like structure on the fracture surface, although no deterioration of tensile properties by hydrogen appeared. In the amorphous region, band-like regions with wavy contrasts were observed, which were often accompanied by cracks at the boundaries. The presence of the amorphous region with band-like regions implies that amorphization occurred due to high-density vacancies accompanied by agglomerations of excess vacancies in the hydrogen-charged SUS 316L stainless steel that was tensile-tested at low temperatures.     

表层表演和深层表演的关系:来自元分析的证据

采用元分析的方法探讨两种主要情绪劳动策略(表层表演、深层表演)之间的相关.经筛选,共有150篇文献的162个独立样本(N = 63629)符合标准.元分析结果发现,表层表演与深层表演呈显著正相关(r = 0.17).量表的作答方式、测量工具、职业类型对表层表演与深层表演的相关具有显著影响.具体表现为,量表的作答方式为频...     

知识对成人归纳推理标签效应的影响

通过对标签所承载的表层类属知识和深层概念知识进行区分,考察了知识对成人归纳推理中标签效应的影响。实验材料为自然标签和人工标签,任务为亲缘关系判断,结果发现在两种材料中都能观察到标签效应。在自然类别中,当标签承载深层知识时,标签承载的表层类属知识的作用会受其影响而减小;在人工类别中,标签作用的发挥会受到标签自身特征的影响,当标签中含有类别信息的汉字时,标签对归纳推理的促进作用更大。     

The interactive effects of role overload and resilience on family-work enrichment and associated outcomes

ABSTRACT

Using an interactionist perspective and conservation of resources (COR) theory, this study examined the interactive effects of resilience and role overload on family-work enrichment and the outcomes of surface acting, emotional exhaustion, and job satisfaction. The model was tested using a sample of 156 full time employees who completed surveys at two time periods. As expected, resilience was positively related to family-work enrichment and family-work enrichment was negatively related to surface acting and emotional exhaustion and positively related to job satisfaction demonstrating mediating effects for family-work enrichment. Role overload moderated the positive relationship between resilience and family-work enrichment such that the relationship was weaker when role overload was high indicating a boundary condition for the favorable effects of resilience. Finally, support was found for the conditional indirect effects of resilience on surface acting, emotional exhaustion, and job satisfaction through family-work enrichment such that the relationships were weaker when role overload was high.     

Postural coordination patterns as a function of dynamics of the support surface

The present study investigated the compensatory postural coordination patterns that emerge in the face of dynamic changes in the surface of support. Adult subjects stood on a moving platform that was sinusoidally translated in the anterior-posterior direction. The frequency and amplitude of the support surface translation were manipulated over a wide range of parameter values. The results revealed that as the frequency of platform motion increased, the postural system systematically exploited the available joint-space degrees of freedom and generated four distinct postural coordination modes (a rigid mode --> ankle mode --> ankle-hip mode --> ankle-hip-knee mode). It appears that upright standing posture has a small set of coordination patterns that are particular to the dynamics of the surface of support.     

Personality Predictors of Protégé Mentoring History

The present study identifies personality characteristics that are predicted to be associated with protégé status in a series of mentoring relationships, an area of research that has not been explored previously. Predictors of mentoring history identified are need for achievement, need for dominance, self-esteem, and tension dissipation. A MANOVA, using number of previous mentors as the independent variable and 4 personality characteristics (need for achievement, need for dominance, self-esteem, and tension dissipation) as outcome variables, showed a significant relationship. Univariate follow-up tests indicated that the number of previous mentoring relationships was significantly associated with need for achievement, need for dominance, and self-esteem, but not tension dissipation. Results are discussed in terms of protégé development, and directions for future research are suggested.     

A combination of Al diffusion and surface nanocrystallization of carbon steel for enhanced corrosion resistance

Surface nanocrystallization is beneficial to the corrosion resistance of passive alloys, but generally has a negative effect on the corrosion behavior of non-passive alloys due to the enhanced surface reactivity. In this study, a combination of Al diffusion treatment and surface nanocrystallization was applied to carbon steel with the aim of exploring an alternative approach to improve the corrosion resistance of non-passive carbon steel. The surface nanocrystallization was achieved by sandblasting and subsequent recovery treatment. The former resulted in severe plastic deformation, while the latter turned high-density dislocation cells into nano-sized grains. The present study demonstrates that the combined Al diffusion and nanocrystallization generated a nanocrystalline Al-containing surface layer on the carbon steel with its surface grain diameter in the range of 10–300 nm. The corrosion resistance of the treated steel was evaluated. It is demonstrated that treated specimens possess increased resistance to corrosion with higher surface electron stability. Surface microstructure of the treated specimens was examined using SEM, AFM, and EDS in order to elucidate the mechanism responsible for the improved corrosion resistance.     

Thermophysical properties of undercooled liquid cobalt

The surface tension of undercooled liquid cobalt has been measured by the oscillating-drop technique combined with electromagnetic levitation. The accuracy of the method was verified by measurements of the surface tension of liquid nickel. The liquid cobalt was undercooled by up to 231K (0.13T _m), and its surface tension determined to be σ_Co =1875 0.348(T-T _m)mNm^-1. From this result, the viscosity, self-diffusion coefficient, density and thermal diffusivity of undercooled liquid cobalt were derived. Using these thermophysical parameters, the growth velocity of cobalt dendrite is calculated and shown to agree well with experimental results. Furthermore, the Marangoni number and the Rayleigh number are calculated; these increase slowly with increasing degree of undercooling.     

儿童数概念发展的影响因素:表面相似性效应与标签效应

本研究主要考查表面相似性效应和标签效应对60名3～5岁儿童数概念发展的影响。实验通过等量匹配任务和数量比较任务测查儿童数概念的发展情况,其中等量匹配任务和数量比较任务都包括了一致和不一致两种条件以考查表面相似性效应对儿童数概念的影响,并通过给物取数任务、给数取物任务和等量匹配任务与数量比较任务的关系测查儿童使用数字标签的能力对儿童数概念形成与发展的影响。结果表明:(1)4岁和5岁组儿童完成等量匹配任务和数量比较任务的正确率显著高于3岁组儿童;(2)儿童在一致条件下完成等量匹配和数量比较任务的正确率显著高于不一致条件的正确率,表明物体的高表面相似性有利于儿童数概念的形成;(3)擅长使用数字标签的儿童完成等量匹配任务和数量比较任务的次数超过几率水平,使用数字标签有利于儿童数概念的发展。