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901.
This study examined the effects of positive affect on working memory (WM) and short-term memory (STM). Given that WM involves both storage and controlled processing and that STM primarily involves storage processing, we hypothesised that if positive affect facilitates controlled processing, it should improve WM more than STM. The results demonstrated that positive affect, compared with neutral affect, significantly enhanced WM, as measured by the operation span task. The influence of positive affect on STM, however, was weaker. These results suggest that positive affect enhances WM, a task that involves controlled processing, not just storage processing. Additional analyses of recall and processing times and accuracy further suggest that improved WM under positive affect is not attributable to motivational differences, but results instead from improved controlled cognitive processing. 相似文献
902.
Shaowen Qian Gang SunQingjun Jiang Kai LiuBo Li Min LiXiao Yang Zhen YangLun Zhao 《Brain and cognition》2013
In this study, we simulated environmental heat exposure to 18 participants, and obtained functional magnetic resonance image (fMRI) data during resting state. Brain functional networks were constructed over a wide range of sparsity threshold according to a prior atlas dividing the whole cerebrum into 90 regions. Results of graph theoretical approaches showed that although brain networks in both normal and hyperthermia conditions exhibited economical small-world property, significant alterations in both global and nodal network metrics were demonstrated during hyperthermia. Specifically, a lower clustering coefficient, maintained shortest path length, a lower small-worldness, a lower mean local efficiency were found, indicating a tendency shift to a randomized network. Additionally, significant alterations in nodal efficiency were found in bilateral gyrus rectus, bilateral parahippocampal gyrus, bilateral insula, right caudate nucleus, bilateral putamen, left temporal pole of middle temporal gyrus, right inferior temporal gyrus. In consideration of physiological system changes, we found that the alterations of normalized clustering coefficient, small-worldness, mean normalized local efficiency were significantly correlated with the rectal temperature alteration, but failed to obtain significant correlations with the weight loss. More importantly, behavioral attention network test (ANT) after MRI scanning showed that the ANT effects were altered and correlated with the alterations of some global metrics (normalized shortest path length and normalized global efficiency) and prefrontal nodal efficiency (right dorsolateral superior frontal gyrus, right middle frontal gyrus and left orbital inferior frontal gyrus), implying behavioral deficits in executive control effects and maintained alerting and orienting effects during passive hyperthermia. The present study provided the first evidence for human brain functional disorder during passive hyperthermia according to graph theoretical analysis using resting-state fMRI. 相似文献
903.
The congruency sequence effect refers to a reduced congruency effect after incongruent trials relative to congruent trials. This modulation is thought to be, at least in part, due to the control mechanisms resolving conflict. The present study examined the nature of the control mechanisms by having participants perform two different tasks in an alternating way. When participants performed horizontal and vertical Simon tasks in Experiment 1A, and horizontal and vertical spatial Stroop task in Experiment 1B, no congruency sequence effect was obtained between the task congruencies. When the Simon task and spatial Stroop task were performed with different response sets in Experiment 2, no congruency sequence effect was obtained. However, in Experiment 3, in which the participants performed the horizontal Simon and spatial Stroop tasks with an identical response set, a significant congruency sequence effect was obtained between the task congruencies. In Experiment 4, no congruency sequence effect was obtained when participants performed two tasks having different task-irrelevant dimensions with the identical response set. The findings suggest inhibitory processing between the task-irrelevant dimension and response mode after conflict. 相似文献
904.
Using low-energy electron microscopy we explore the fluctuations of step edges on Pt(111) in the temperature range 1190?K<T<1520?K. Below 1400?K the relaxation times vary with wave vector q as q 3, and above 1400?K as q 2, while the observed activation energy changes from 1.25 to 2.75?eV. A discussion shows that surface diffusion is responsible for the rates at low temperatures, and that bulk vacancy diffusion becomes dominant above 1400?K. We infer that a similar crossover must occur for steps on most metal surfaces. The step stiffness is determined as 175 ± 20?meV?nm?1 at 1500?K. 相似文献
905.
Work function (WF) can be measured using the Kelvin probe (KP) technique to characterize surface behavior of micro/nanostructures grown on substrates such as metals or semiconductors. However, for such micro/nanostructures, substrates with different WF can strongly affect the measurements if they are exposed directly to face the Kevin probe tip. In this article, a model is proposed to investigate the WF of sparse ZnO nanorods grown on an Si substrate. It is demonstrated that theoretical results from the model are consistent with experimental observations performed using a KP system. 相似文献
906.
Transformation and misfit dislocations are used to describe the motion of glissile interfaces with one set of misfit dislocations in the framework of the Frank?Bilby equation. The sweep of these glissile interfaces brings about an invariant-plane-strain type shape deformation. Our approach explains the glissile motion of martensitic interfaces and small-angle symmetrical tilt grain boundaries. It is consistent with the phenomenological theory of martensite crystallography but more flexible. 相似文献
907.
H.W. Yang R.C. Wang X.G. Yuan R.D. Li J.Q. Wang M.J. Tan 《Philosophical Magazine Letters》2013,93(10):656-663
The effect of chamber gas pressure on the amorphicity of Al85Ni5Y10 alloy was studied for the melt-spinning process. The amorphicity of as-quenched ribbons was characterized by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The chamber atmosphere pressure is crucial to the cooling rate of melt spinning. At high vacuum, at pressure less than 0.001?atm, fully crystalline fragments are obtained. Monolithic amorphous ribbons were only obtained at a gas pressure of 0.1?atm, 0.2?atm or higher. The extended contact length between ribbons and the copper wheel contributes to the high cooling rate of melt spinning in Al-based glass forming alloys; that is supported by images recorded by a high-speed camera. Higher chamber pressure increases contact length between ribbons and the wheel, which is qualitatively elucidated by Bernoulli's equation. 相似文献
908.
The alpha -> beta polytypic transformation in SiC was observed during ball milling at room temperature. Microstructural evolution was characterized on an atomic scale by high-resolution electron microscopy (HREM). HREM observations showed that partial dislocations play an important role in the transformation under the complicated conditions during ball milling. 相似文献
909.
在建构道德存有论的过程中,牟宗三非常重视"觉他"的思维方式问题,认为这种思维方式即是康德所说的智的直觉。康德不承认人类可以有智的直觉,儒家则承认人完全可以有这种能力,所以儒家超越了康德。牟宗三这一观点在学界影响很大,人们一般都是从正面理解,目前尚无人系统而明 相似文献
910.
Despite the increased use of sensor technologies, including unmanned vehicles, the vast majority of improvised explosive device (IED) detections are made by human vision. Thus, TRAC-Monterey developed a simulation-based training prototype called the perceptual learning trainer (PLT). Fourteen novice and 5 expert IED detectors participated in human-in-the-loop experiments in which all participants were trained using the PLT tool while their eye-movement and IED detection performance were tracked in real-time. A series of 100 IED images with various degrees of difficulty was used for the training session. Pre- and posttraining assessments were conducted. Both speed and accuracy improved after just 1 session of the PLT training: RT decreased by 3.7 s for novices (p < .001) and 3.4 s for experts (p = .031), and detection probability increased by 5.9% for novices (p = .001). The PLT tool improved IED detection performance more in novice IED detectors than in experts. Novices and experts showed different visual scan patterns. 相似文献