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221.
We propose a new structure for piezoelectric gyroscope application. It consists of a two-layered plate of AlN with inclined c-axes. Through a theoretical analysis, it is shown that when the plate is electrically driven into thickness-shear (TSh) vibration in one direction and is rotating about the plate normal, the rotation causes a TSh vibration in a perpendicular direction with an electrical output which can be used to measure the angular rate of the rotation. Since AlN can be made into thin film devices much smaller than conventional crystal acoustic wave devices, the proposed gyroscope can be made much smaller than existing piezoelectric gyroscopes. The structure can also work with other crystals of class 6mm such as ZnO and polarized ceramics.  相似文献   
222.
We propose the use of thickness-twist (TT) and face-shear (FS) vibration modes of an AT-cut quartz crystal plate resonator for simultaneous determination of the inertia and stiffness of a thin film deposited on a crystal surface. A theoretical analysis using Mindlin's first-order theory for crystal plates is performed to demonstrate the idea. Expressions for the stiffness ratio and mass ratio between the thin film and the resonator are presented in terms of frequency shifts of FS and TT modes, which are experimentally measurable. A numerical example is given.  相似文献   
223.
目前社会阶层分化进程中的医患关系比较紧张,医患信息行为起了很大作用.由于历史原因多数医师未能认识到医患信息行为对医患沟通及医患关系的影响.患者作为医疗信息掌握的弱势群体,其对从医师处获得信息的依赖将长期存在,医师与患者信息行为必然相互影响.针对信息行为建立相应的培训及评价机制是十分必要的.  相似文献   
224.
With intensively collected longitudinal data, recent advances in the experience-sampling method (ESM) benefit social science empirical research, but also pose important methodological challenges. As traditional statistical models are not generally well equipped to analyze a system of variables that contain feedback loops, this paper proposes the utility of an extended hidden Markov model to model reciprocal the relationship between momentary emotion and eating behavior. This paper revisited an ESM data set (Lu, Huet, &; Dube, 2011 Lu, J., Huet, C., &; Dubé, L. (2011). Emotional reinforcement as a protective factor for healthy eating in home settings. The American Journal of Clinical Nutrition, 94(1), 254261. http://dx.doi.org/10.3945/ajcn.110.006361[Crossref], [PubMed], [Web of Science ®] [Google Scholar]) that observed 160 participants' food consumption and momentary emotions 6 times per day in 10 days. Focusing on the analyses on feedback loop between mood and meal-healthiness decision, the proposed reciprocal Markov model (RMM) can accommodate both hidden (“general” emotional states: positive vs. negative state) and observed states (meal: healthier, same or less healthy than usual) without presuming independence between observations and smooth trajectories of mood or behavior changes. The results of RMM analyses illustrated the reciprocal chains of meal consumption and mood as well as the effect of contextual factors that moderate the interrelationship between eating and emotion. A simulation experiment that generated data consistent with the empirical study further demonstrated that the procedure is promising in terms of recovering the parameters.  相似文献   
225.
Differences in reasoning styles between Chinese and European Americans held even when controlling for the language of testing. Bilingual Chinese organized objects in a more relational and less categorical way than European Americans, whether tested in English or in Chinese. Thus, culture affects categorization independent of the testing language. Nevertheless, language affected some Chinese bilinguals' categorization. The responses of Chinese from the Mainland and Taiwan were more relational when tested in Chinese than when tested in English. Responses of Chinese from Hong Kong and Singapore were equally relational when tested in Chinese and in English. Age and context of learning English are discussed to explain the differential language effects among different Chinese groups. Theoretical and methodological implications are discussed.  相似文献   
226.
Training-induced and electrically induced potentiation in the neocortex   总被引:3,自引:0,他引:3  
Long-term potentiation (LTP) shares many properties with memory and is currently the most popular laboratory model of memory. Although it has not been proven that memory is based on an LTP-like mechanism, there is evidence that learning a motor skill can induce LTP-like effects. This evidence was obtained in a slice-preparation experiment, which precluded within-animal comparisons before and after training. In the present experiments, Long-Evans rats were unilaterally trained to acquire a forelimb reaching and grasping skill. Evoked potentials were found to be larger in motor cortex layer II/III in the trained, compared to the untrained, hemisphere in slice, acute, and chronic preparations. Consistent with previous research, the trained hemisphere was less amenable to subsequent LTP induction. Furthermore, the application of either LTP- or LTD-inducing stimulation during the training phase of the reaching task disrupted the acquisition of the skill, providing further evidence that memory may be based on an LTP mechanism.  相似文献   
227.
Positive risk-taking is a crucial element of individual creativity and social development. However, little is known regarding the relation between individual neural differences and positive risk-taking. In addition, critical thinking (CT) and gender have been proven to be two important individual-specific factors associated with risk-taking behaviour, and different levels of CT and gender may have diverse effects on the relationship between brain structure and positive risk-taking. The present study examined the relationship between positive risk-taking and regional grey matter volume (rGMV) in 292 healthy participants. The results showed that positive risk-taking was significantly positively associated with the rGMV of the posterior cingulate cortex (PCC). In addition, this study investigated individual differences in critical thinking and found that it moderated the relationship between rGMV and positive risk-taking. Individuals with lower CT had a stronger association between rGMV and positive risk-taking. Further analysis showed that for males, a greater rGMV was significantly linked to higher positive risk-taking tendency. These findings suggest that PCC evaluates risk and serves as a behavioural adaptation hub for positive risk-taking. This study thereby contributes to the literature on individual differences in brain structure and risk-taking by elucidating the moderating effects of CT and gender in healthy adults.  相似文献   
228.
本研究采用负启动范式,设置不同的认知负荷任务,探究抑制控制在儿童和成人类比映射中的作用。实验一中,31名7岁儿童、33名10岁儿童和34名成人完成高认知负荷的相对大小类比映射的负启动任务。结果表明,所有群体均出现负启动效应,且负启动效应随年龄增长而减小。实验二中,30名7岁儿童、30名10岁儿童和32名成人完成低认知负荷的相对大小类比映射的负启动任务。结果表明,所有群体均出现负启动效应,但负启动效应无显著年龄差异。本研究的结果揭示了抑制控制和认知负荷在类比映射发展中的重要作用。  相似文献   
229.
为了探究成就目标定向在学业自我概念与学业成绩关系中的调节作用,采用语文学业自我概念量表、数学学业自我概念量表和成就目标定向量表对1515名初中生进行测查。结果显示:(1)初中生语文-数学学业自我概念建构过程符合内/外参照模型(Internal/External Frame of Reference Model, I/EM);(2)掌握回避对I/EM的维度比较路径存在调节作用,掌握回避得分越高越易受维度比较效应的影响,该现象对于语文成绩和数学成绩相对差的学生更明显;(3)成绩回避对I/EM的社会比较路径存在调节作用,成绩回避得分越高越不易受社会比较效应的影响,该现象对于语文成绩和数学成绩相对好的学生更明显。本研究揭示了持有不同成就目标定向的初中生在学业自我概念建构过程中的差异,对引导初中生建构积极学业自我概念具有重要启示。  相似文献   
230.
语义的自动加工和选择性注意对Stroop效应的影响   总被引:3,自引:1,他引:2  
本实验用正常人和聋哑人作被试进行比较,试图探讨语义的自动加工和选择性注意对Stroop效应的影响。将“红”“绿”“黄”“蓝”四个汉字中的每一个都用这四种颜色中的三种写成,然后按着事先排列好的顺序,分组呈现,并且在两种条件下分别要求被试延迟不同的时间进行反应,一种是刺激呈现前就告诉被试对“字”或“色”反应;另一种是刺激呈现后间隔不同的时间再向被试提出对“字”或“色”反应。实验结果发现,聋哑人和正常人在色—字干扰任务作业上没有明显的差异,说明语义的自动加工是一个普遍现象;而选择性注意能在很大的程度上改善被试的作业成绩,但颜色命名仍比字词反应困难;Stroop效应在延迟反应条件下发生变化,这种变化说明Stroop效应与记忆过程有联系。  相似文献   
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