The Application of X-rays for an Electrodeposition of Composite Coatings with Modified Structures and Properties

Experimental studies of the effect of X-rays on the process of electrolytic deposition of composite coatings are reviewed in this paper. Particular emphasis will be on the applications of X-rays for both the modification of a structure and the mechanical characteristics of galvanic coatings. In particular, this research investigates the Co/SiO2 coatings deposited from aqueous solutions under the effect of X-rays. The results of extensive investigations into the dispersing ability of electrolytes with SiO2 nanoparticles and a mass rate of composite coatings Co/SiO2 indicates that the method of electroplating under the effect of X-rays during the process results in the intensification of diffusion in the electrolyte volume and creates dense, uniform coatings. This research demonstrates that exposure of an electrolytic cell to X-rays during the electroplating process of Co/SiO2 results in an orienting effect on the formation of crystal grains and allows for the creation of dense, morphology uniform coatings with increased hardness and improved adhesion.

Extension of grouting-induced splitting fractures in materials similar to coal rocks containing prefabricated fractures

To reveal the influence of prefabricated fractures (PFs) with different parameters on the extension of grouting-induced splitting fractures, a combination of numerical simulation and physical experiments were used to carry out grouting trials on similar materials to coal rock. The RFPA software was used to simulate the whole process of fracture initiation and expansion of coal rock with PFs during grouting. In the experiment, acoustic emission (AE) technology was used to monitor the extension process of grouting-induced splitting fractures. The results demonstrated that when the PFs do not intersect with the grouting holes, the extension of grouting-induced splitting fractures in rocks containing PFs experienced four stages: splitting and penetrating, slurry filling, fracture splitting and splitting extension. PFs have an orienting effect on the direction of grouting fracture extension and the size of the PFs influenced the extension of the grouting-induced splitting fractures: the larger the size, the easier the surrounding rocks were ruptured, the easier the connection was formed of channels between the grouting-induced splitting fractures and the PFs were formed, and the more complex the secondary splitting pattern in the PFs. This indicated that the angle of PFs played a decisive role in determining the extension direction of grouting-induced splitting fractures. The extension of grouting-induced splitting fractures during grouting of rock mass with different parameters is revealed by numerical simulation and experimental results.

Некоторые особенности конденсации атомов кремния на поверхности монокристалла вольфрама

Using the methods of the field emission microscopy, the condensation of Si on the W surface at various temperatures T of the substrate and numbers n of monoatomic layers of the deposited condensate is studied. At low temperatures T ~ 600 K, a low-temperature Si-monolayer with the structure of pure W is formed on the surface, whereas another structure of a high-temperature monolayer, namely surface siliside is formed at T > 1000 K. The low-temperature monolayer and surface siliside are differ in their orienting effect when constructing the Si layers. In the case of condensation on a low-temperature monolayer, crystallites of Si are formed starting already from the third monolayer at n > 3, whereas the Si crystallites grow during the condensation on surface siliside starting from n > 300 monolayers. The energy activation of the volume diffusion Qdif of the Si-atoms into W and desorption Qdes from W surface are determined.

Bilingualism and Attention in Typically Developing Children and Children With Developmental Language Disorder

Purpose The aim of the current study was to investigate whether dual language experience modulates the efficiency of the 3 attentional networks (alerting, orienting, and executive control) in typically developing (TD) children and in children with developmental language disorder (DLD). Method We examined the attentional networks in monolingual and bilingual school-aged children (ages 8–12 years) with and without DLD. TD children (35 monolinguals, 23 bilinguals) and children with DLD (17 monolinguals, 9 bilinguals) completed the Attention Network Test ( Fan et al., 2002 ; Fan, McCandliss, Fossella, Flombaum, & Posner, 2005 ). Results Children with DLD exhibited poorer executive control than TD children, but executive control was not modified by bilingual experience. The bilingual group with DLD and both TD groups exhibited an orienting effect, but the monolingual group with DLD did not. No group differences were found for alerting. Conclusions Children with DLD have weak executive control skills. These skills are minimally influenced by dual language experience, at least in this age range. A potential bilingual advantage in orienting may be present in the DLD group.

Structural Brain Correlates of Attention Dysfunction in Lewy Body Dementias and Alzheimer’s Disease

Lewy body dementia (LBD) and Alzheimer’s disease (AD) are common forms of dementia that have different clinical profiles but are both commonly associated with attentional deficits. The aim of this study was to investigate efficiency of different attentional systems in LBD and AD and its association with brain structural abnormalities.We studied reaction time (RT) data from 45 LBD, 31 AD patients, and 22 healthy controls using the Attention Network Test to assess the efficiency of three different attentional system: alerting, orienting, and executive conflict. Voxel-based morphometry was used to investigate relations between different attention components and cortical volume.Both dementia groups showed slower overall RTs than controls, with additional slowing in LBD relative to AD. There was a significant alerting effect in controls which was absent in the dementia groups, the executive conflict effect was greater in both dementia groups compared to controls, but the orienting effect did not differ between groups. Mean RT in AD was negatively correlated with occipital grey matter volume and in LBD orienting efficiency was negatively related to occipital white matter volume. Given that previous studies in less impaired patients suggest a maintenance of the alerting effect, the absent alerting effect in our study suggests a loss of alerting efficiency with dementia progression. While orienting was largely preserved, it might be related to occipital structural abnormalities in LBD. Executive function was markedly impaired in both dementia groups, however, the absence of relations to brain volume suggests that it might be more related to functional rather than macrostructural pathophysiological changes.

Saccades and smooth pursuit eye movements trigger equivalent gaze-cued orienting effects

Research has established that a perceived eye gaze produces a concomitant shift in a viewer’s spatial attention in the direction of that gaze. The two experiments reported here investigate the extent to which the nature of the eye movement made by the gazer contributes to this orienting effect. On each trial in these experiments, participants were asked to make a speeded response to a target that could appear in a location toward which a centrally presented face had just gazed (a cued target) or in a location that was not the recipient of a gaze (an uncued target). The gaze cues consisted of either fast saccadic eye movements or slower smooth pursuit movements. Cued targets were responded to faster than uncued targets, and this gaze-cued orienting effect was found to be equivalent for each type of gaze shift both when the gazes were un-predictive of target location (Experiment 1) and counterpredictive of target location (Experiment 2). The results offer no support for the hypothesis that motion speed modulates gaze-cued orienting. However, they do suggest that motion of the eyes per se, regardless of the type of movement, may be sufficient to trigger an orienting effect.

Stress-level-dependent microstructure evolution and deformation behaviors during creep age forming of AA2219 alloy

Creep age forming (CAF) can shape and strengthen the sheet metals loaded externally at elevated temperature by corresponding creep/stress-relaxation and age hardening. Understanding the deformation and strengthening behavior at different stress levels plays a pivotal role in accurate prediction of CAF. This work experimentally investigates the effect of stress level on the evolution of both properties and microstructures, including precipitates and dislocations, during CAF. The microstructural evolution is characterized in detail by scanning/transmission electron microscopy (S/TEM) and X-ray diffraction (XRD). Stress orienting effect of θ» occurs at low-stress loaded samples and results in a decline in the hardening potential of creep-aging. A bimodal distribution of precipitates consisted of θ» homogeneously formed in the matrix and θ' heterogeneously formed on dislocations is found in the high-stress loaded samples, giving rise to a significant enhancement of hardening response. In addition, the creep strain increases drastically when the loading stress is higher than the initial yield strength. The relevant mechanisms for the transition of the obtained strength and creep behaviors with the applied stress are discussed based on microstructure observations.