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841.
对285名小学三年级和四年级儿童进行了连续三年的追踪调查,分析了儿童同伴尊重发展趋势及其在群体间的差异,探讨了社交领导性在儿童同伴尊重发展中的预测作用。结果表明:(1)童年中后期儿童与同伴之间的获得尊重与表现尊重具有显著增长趋势;(2)三年间女孩的表现尊重均高于男孩但增长速度无差异;女孩的获得尊重增长速度高于男孩;(3)儿童的社交领导性能够显著正向预测儿童同伴尊重的发展趋势。  相似文献   
842.
本研究采用纵向设计,对170名儿童(实验组:101人;对照组:69人)进行为期两学年的追踪,旨在探讨书法练习对儿童情绪状态及认知性情绪调节策略发展的影响。研究发现,1)以前测成绩为协变量,后测时实验组的积极情绪显著高于对照组;2)实验组在“积极重新关注”、“计划”两维度上的情绪调节策略得分增量(后测-前测)显著高于对照组。结果表明,书法练习对儿童情绪及其调节策略发展具有促进作用。  相似文献   
843.
The authors explored the phenomenon of unintentional changes in the equilibrium state of a multijoint effector produced by transient changes in the external force. The subjects performed a position-holding task against a constant force produced by a robot and were instructed not to intervene voluntarily with movements produced by changes in the robot force. The robot produced a smooth force increase leading to a hand movement, followed by a dwell time. Then, the force dropped to its initial value leading to hand movement toward the initial position, but the hand stopped short of the initial position. The undershoot magnitude increased linearly with the peak hand displacement and exponentially with dwell time (time constant of about 1 s). For long dwell times, the hand stopped at about half the total distance to the initial position. The authors interpret the results as consequences of a drift of the referent hand coordinate. Our results provide support for back-coupling between the referent and actual body configurations during multijoint actions and produce the first quantitative analysis of this phenomenon. This mechanism can also explain the phenomena of slacking and force drop after turning visual feedback off during accurate force production task.  相似文献   
844.
845.
The wetting behaviour and associated pressure effect of water in single-walled carbon nanotubes (SWCNTs) are investigated through molecular dynamics (MD) simulations. It is found that water molecules can enter SWCNTs via surface diffusion, and the effective infiltration rate increases with pressure. The effect of pressure on infiltration rate is highly non-linear, exhibiting characteristics of both hydrophilic and hydrophobic surfaces. There exists a nominal infiltration pressure that is dependent on the SWCNT size, above which the water flux is significantly increased.  相似文献   
846.
847.
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.  相似文献   
848.
Abstract

The local translational order of the icosahedral quasicrystalline phase in rapidly solidified V41Ni36Si23 has been investigated by means of selected-area electron diffraction and high-resolution electron microscopy. Experimental results show that translational order always occurs in the twofold direction and can be observed when the quasicrystal is examined along its fivefold and threefold as well as twofold axes. Sometimes it occurs in two or three coplanar twofold directions simultaneously. In these cases some crystalline islands exist in the icosahedral quasicrystal and this corresponds to the initial stage of transformation from a quasicrystal to the stable crystalline phase.  相似文献   
849.
In daily life, people frequently need to observe dynamic objects and temporarily maintain their representations in visual working memory (VWM). The present study explored the mechanism underlying the binding between perceptual features and locations of dynamic objects in VWM. In three experiments, we measured and compared the memory performance for feature-location binding of multiple dynamic and static objects. The results showed that the feature-location binding was impaired for the dynamic objects compared with the static objects. The impairment persisted when the global spatial configuration of the objects remained intact during the motion, as well as when the binding task was relatively easy, such as binding between single-feature objects and coarse locations. The results indicate that object features and locations are not maintained in VWM as well-integrated object files; rather, the formation of feature-location binding may require additional processes, which are disrupted by the constant change of locations in dynamic circumstances. We propose a consolidation process as possible underlying mechanism, and discuss factors that may influence the strength of feature-location binding in dynamic circumstances.  相似文献   
850.
尤佳  周斌 《中国道教》2011,(2):16-24
唐朝是我国道教发展的繁盛时期,尤其是唐玄宗在位期间,李唐王朝的崇道活动更是被推向了顶峰。但是唐朝中期以后,道教在前进的发展进程中却遭遇到强劲的阻力,先是安史之乱,后  相似文献   
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