Intermetallic compound identification and Kirkendall void formation in eutectic SnIn/Cu solder joint during solid-state aging

Microstructural investigations were performed on the interfacial reactions between eutectic SnIn solder and Cu substrate during reflowing at 433?K and solid-state aging at 373?K. Cu₂(In,Sn) was identified as the only intermetallic compound (IMC) at the interface, which consists of two sublayers with different morphology, a fine-grained sublayer at the Cu side and a coarse-grained sublayer at the solder side. During solid-state aging, voids were found between these two Cu₂(In,Sn) sublayers but not at the substrate interface, which is also attributed to the Kirkendall effect considering the different diffusion fluxes of Sn or In and Cu atoms in different sublayers.     

Influence of precipitation of intermetallics on Young's modulus in nickel and zirconium base alloys

The influence of precipitation of intermetallic phases on changes in Young's modulus in nickel and zirconium base alloys is discussed. This study shows clearly for the first time that the change in the modulus due to precipitation of intermetallic phases in these alloys is essentially governed by the change in the modulus of the matrix due to removal of precipitation forming elements, and not by the modulus of the precipitated intermetallics or the matrix/intermetallic interface.     

A new counter-example to Kelvin's conjecture on minimal surfaces

A survey of the published literature on undercooled metallic and oxide melts suggests that phase selection during solidification can be categorized as nucleation controlled or growth controlled. Common characteristics governing the phase-selection pathway have been identified for various alloy systems. It is recognized that when competing stable and metastable phases share the same crystalline characteristics and have comparable interface kinetic coefficients, the principle of nucleation control applies for primary phase formation in a deeply undercooled melt. However, there can be a difference of two or three orders of magnitude in the interface kinetic coefficients for competing phases, either between an ordered intermetallic compound and a disordered solid solution, or between a crystalline phase with a high level of complexity and a simple crystal. In such cases, the principle of growth control will apply; more specifically, the phase with the faster growth kinetics should be favoured and the competing counterpart with sluggish interface kinetics should be suppressed at high undercoolings. Some simple predictions are suggested on the basis of this principle when considering stable and metastable phase diagrams. The specific conditions under which the present categorization is applicable are outlined. Future work is required to elucidate phase competition under conditions of very rapid solidification.     

Criteria of kinetic suppression of lateral growth of intermediate phases

In many cases, the formation of intermediate phases in solid-state reaction starts from nucleation, proceeds at first by lateral spreading along interface in the form of narrow layer and after that continues slow growth in normal direction. So far, the lateral growth stage was considered as something almost instant. Yet, if the emerging phase is not the first one and the already growing phase layer has high diffusivity, the lateral growth can be also kinetically suppressed due to ‘sucking out’ of atoms from the moving interface into the growing first phase layer. Criteria of such suppression are formulated and examples of real systems are discussed.     

Revisitation of the luminance conditions for the occurrence of the achromatic neon color spreading illusion

This paper develops the idea (Bressan, 1993) that neon spreading derives from the perceptual scissioning of ordinary assimilation color, a process identical to that occurring with nonillusory colors in phenomenal transparency. It is commonly held that the critical elements in achromatic neon spreading patterns must be of luminance intermediate between that of the embedding lines and of the background. The interpretation of neon spreading on the basis of color scissioning, however, predicts that neon spreading should also be observed for different luminance hierarchies, provided that these are compatible with transparency. This prediction found experimental support in the present work. The results suggest that (1) the widespread notion that chromatic and achromatic neon spreading must be mediated by separate mechanisms is unwarranted; (2) the widespread notion that color spreading in ordinary assimilation patterns and color spreading in neon patterns must be mediated by separate mechanisms is unwarranted; and (3) other than pointing to the way in which the overall organization of a scene affects the mode of color appearance, the neon spreading effect may not convey any extra theoretical relevance.     

Increased spreading activation in depression

The dopaminergic system is implicated in depressive disorders and research has also shown that dopamine constricts lexical/semantic networks by reducing spreading activation. Hence, depression, which is linked to reductions of dopamine, may be associated with increased spreading activation. However, research has generally found no effects of depression on spreading activation, using semantic priming paradigms. We used a different paradigm to investigate the relationship between depression and spreading activation, one based on word frequencies. Our sample included 97 undergraduates who completed the BDI-II and the Controlled Oral Word Association test as well as the Animal Naming test. The results indicated that the group scoring within the depressed ranged evidenced greater spreading activation as compared to those who scored within the normal range on the BDI-II. The implications of these results as they relate to creativity in depression is discussed.     

Faceting of a rough solid–liquid interface of a metal induced by forced convection

The solid–liquid interface of metallic systems of small entropy of fusion is characterized by a rough interface and dendritic morphology. In contrast, systems of high entropy of fusion like semimetals and semiconductors show smooth interfaces and facetted interfaces. The present work demonstrates that, in an undercooled melt of a metal–metalloid alloy Ni₂B of intermediate entropy of fusion, a transition from a rough to a smooth interface is induced by forced convection of the melt. Electrostatic levitation is used to container-less undercool droplets in a quiescent state with no convection while electromagnetic levitation (EML) is used to undercool droplets with forced convection. The growth velocity of the solid phase is monitored as a function of undercooling by a high-speed video camera. The data are analysed within dendrite growth theory. In the case of EML, a transition from a rough to a smooth interface is indicated during dendrite growth in the undercooled melt. This is confirmed by facetted microstructures of samples solidified upon undercooling by EML. Hopper-like crystals are formed like in non-metals as bismuth, halite and ice.     

Object-based attention: sensory enhancement or scanning prioritization

The three experiments reported here test whether object-modulated attentional spreading can be obtained when the target location is 100% certain. Experiment 1 uses the reaction time (RT)-based flanker task similar to Shomstein and Yantis (2002), and replicates the null result of the object-modulated attentional spreading. RT and accuracy (ACC) have been shown to reflect different processes: postperceptual decision vs. perceptual process (Santee & Egeth, 1982). Experiment 2 adopts the data-limited ACC-based measure and reports that attention could spread within the attended object. To avoid ceiling effects, Experiment 3 adjusts the presentation time based on the trials where the target and flankers were compatible and on the same objects, and provides the convergent evidence supporting the object-modulated attentional spreading. These results suggest that because the RT-based measure is less sensitive in reflecting the quality of perceptual representations, it is not sufficiently a strong evidence to distinguish between sensory enhancement and scanning prioritization accounts.     

论故意传播艾滋病行为的法律定性

目前与故意传播艾滋病行为相关的刑事犯罪正在悄然上升,对于故意传播艾滋病行为究竟应以什么罪名定性争议很大.从医学的角度看,传播艾滋病行为的途径不同,故意传播艾滋病行为的法律定性也必然不同.     

Effects of luminance contrast on color spreading and illusory contour in the neon color spreading effect

The present study examined whether color spreading and illusory contours in the neon color spreading effect of Ehrenstein figures are governed by different mechanisms. In the experiment, Ehrenstein figures with colored crosses inserted in the central gaps were used. There were three luminance conditions: the luminance of the Ehrenstein figures was lower than, the same as, or higher than the luminance of the background. In each condition, 16 trials (2 sets of instructions X 8 repetitions) were conducted in a random order. Subjects were required to adjust the luminance of the colored crosses according to one of the two sets of instruction given before each trial. One was to adjust the upper and lower thresholds in the luminance of the colored crosses such that their color was seen to spread out of the crosses. The other was to adjust the thresholds such that circular illusory contours were visible. It was found that illusory contours disappeared and the color spreading remained when the crosses and the Ehrenstein figures were in or nearly in isoluminance or when the Ehrenstein figures and the background were in isoluminance. These results suggest that color spreading and illusory contours are governed by different mechanisms.     

Marker-passing over Microfeatures: Towards a Hybrid Symbolic/Connectionist Model

Spreading activation, in the form of computer models and cognitive theories, has recently been undergoing a resurgence of interest in the cognitive science and AI communities. Two different types of cognitive models have been proposed to explain the activation spreading results. One approach, that of marker-passing, concentrates on the spreading of symbolic information through an associative knowledge representation. The other technique, including the work in local connectionism, has focused on the passage of numeric information through a network. In this article, it is shown that these two techniques can be merged. The implementation of a mechanism in which a local-connectionist-like model is integrated with a symbolic marker-passer is described and shows that the combined system is more powerful than either of the separate models alone. Finally, some early steps toward a hybrid model in which a distributed network is used to learn the microfeatures is described.     

Finger spreading as an indicator of psychomotor activity and laterality

In 23 healthy right- and left-handers and in 8 psychotic patients the angels between fingers were measured after maximal spreading. It can be demonstrated, that there are differences in spreading out between right- and lefthanders. The dominance of the right hand in right-handers is fluctuating. In depressiv psychotics and patients after schizophrenia we found decrease of spreading out. The laterality imbalance in psychoses we interprete as a sign of hemispherial dysfunktion.     

Recall of word lists is enhanced with increased spreading activation

ABSTRACT

Some evidence exists supporting a relationship between spreading activation in semantic/lexical memory networks and episodic memory. However, the results have been mixed and there have been no investigations examining whether a relationship exists between variability in spreading activation and episodic memory. Hence, we sought to investigate these potential relationships. Thirteen individuals were administered the Hopkins Verbal Learning Test–Revised (HVLT-R) and the Controlled Oral Word Association Test (COWAT). The average word frequency of all the “F” words generated on the COWAT was used as a measure of spreading activation. Variability in spreading activation was assessed by calculating the variability of the word frequencies from the COWAT across time. The results confirmed our hypotheses, with significant negative correlations found between free recall on the HVLT-R and both the average word frequency and measures of variability in spreading activation.     

Objects do not aid inhibition of return in crossing the vertical meridian

Location-based cuing experiments have shown that inhibition of return (IOR) spreads beyond a cued location but appears to be confined to the cued hemifield by the vertical meridian. Previous studies have also shown that IOR can spread across objects and here we investigate whether an object can be used to mediate the spreading of IOR into the opposite hemifield. Two experiments used a rectangular object that surrounded four target locations, two to the left and right of a central fixation point. The spreading of IOR in the presence of the object was determined and compared with a condition where the object-frame was absent. Object-present and object-absent trials were either mixed within a block (Experiment 1) or divided into separate blocks (Experiment 2). Both experiments revealed robust inhibition in the cued but not the uncued hemifield, further demonstrating the hemifield-based spreading of IOR.     

广告传播途径与人们对产品确信度的影响

通过三个实验考察了广告传播途径与人们对产品确信度之间的关系。实验一发现,中心传播途径能够增加被试对科技品的确信度,而边缘途径能够增加被试对日用品的确信度;中心途径能够增加场独立被试对产品的确信度,边缘途径能够增加场依存被试对产品的确信度。实验二发现,反自身利益的广告传播更能够增加被试对产品的确信度;实验三发现,间接传播能够增加被试对产品的确信度,产品类型与传播途径及传播途径与被试认知风格之间都存在着交互作用。     

Choice both affects and reflects preferences

The free-choice paradigm is a widely used paradigm in psychology. It has been used to show that after a choice between two similarly pleasant stimuli, the pleasantness of the chosen one tends to increase, whereas the pleasantness of the rejected one tends to decrease—a spreading of alternatives. However, the methodological validity of the free-choice paradigm to study choice-induced preference change has recently been seriously questioned [Chen, K. M., & Risen, J. L. (2010). How choice affects and reflects preferences: Revisiting the free-choice paradigm. Journal of Personality and Social Psychology, 99, 573–594. doi:10.1037/a0020217]. According to this criticism, the classically reported spreading of alternatives between the first and second rating sessions cannot be unambiguously interpreted to reflect a true change in preferences and can be observed even for completely static preferences. Here, we used two measurement sequences, a classical Rating 1–choice–Rating 2 sequence and a control Rating 1–Rating 2–choice sequence, to disentangle the spreading of alternatives driven by the effect of choice from the artefactual effect highlighted by Chen and Risen. In two studies using different stimulus material (faces and odours), we find that choice has a robust modulatory impact on preferences for rejected odours, but not for chosen odours and not for faces.     

Internationalisation of information services for publishers' open access policies: the DINI multilingual integration layer

It is essential for the strategy of open access self-archiving that scientific authors are given comprehensive information on publisher copyright policies. DINI, the German Initiative for Networked Information, has developed a German (and potentially multilingual) interface to the English SHERPA/RoMEO service to provide additional information on German publishers' open access policies. As a next step, this interface was enhanced to an integration layer combining different sources on publisher copyright policies. This integration layer can be used in many different contexts. Together with the SHERPA/RoMEO team, DINI aims to build an international support structure for open access information.     

Guilty by mere association: evaluative conditioning and the spreading attitude effect

Five experiments investigated the phenomenon that attitude formation is not confined to the co-occurrence of an attitudinal object with an evaluated experience. The pairing of a target with a (dis)liked person not only affects the evaluation of the previously neutral person but spreads to other individuals who are (pre)associated with the target (spreading attitude effect). Experiments 1 and 2 provided evidence for the spreading attitude effect in appetitive as well as aversive evaluative conditioning. Experiment 3 showed that the spreading attitude effect is a robust phenomenon resistant to extinction. Experiment 4 demonstrated that attitude spread can be transferred to 2nd-order conditioning. Finally, Experiment 5 supports the notion that the spreading attitude effect is not dependent on cognitive resources. Implications for social as well as applied psychology are discussed.     

Characterization of quasicrystalline primary intermetallic particles in Mg?8wt%Zn?4wt%Al casting alloy

The quasicrystal structure of primary intermetallic particles found in the ascast microstructure of a permanent mould-cast Mg-8wt%Zn-4wt%Al alloy has been characterized using transmission electron microscopy. Most primary intermetallic particles have an average composition of Mg     

A concise derivation of the contact conditions at a migrating sharp interface

A sharp interface model can be used to simulate the kinetics of diffusional phase transformations provided the transformation process is controlled by migration of the interface and by diffusion of components in the bulk phases only. The contact conditions at the migrating sharp interface can be derived by applying the principles of mass balance and maximum dissipation. A concise derivation of the contact conditions on this basis is presented in this work.