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1.
The deformation microstructures of nickel single crystals (99.945 wt.%) during dynamic plastic deformation and quasi-static compression to a true strain of 0.20 were comparatively investigated. The deformation microstructures are orientation dependent, forming cell structure, slip plane aligned or not slip plane aligned extended boundaries. It is found that the orientation spread decreases, remains unchanged and becomes enhanced when loading along 〈0?0?1〉, 〈0?1?1〉 and 〈1?1?1〉, respectively, as strain rate increases.  相似文献   

2.
The acquisition of lever pressing by naive rats, in the absence of shaping, was studied as a function of different rates and unsignaled delays of reinforcement. Groups of 3 rats were each exposed to tandem schedules that differed in either the first or the second component. First-component schedules were either continuous reinforcement or random-interval 15, 30, 60 or 120 s; second-component schedules were fixed-time 0, 1, 3, 6, 12, or 24 s. Rate of responding was low under continuous immediate reinforcement and higher under random-interval 15 s. Random interval 30-s and 60-s schedules produced lower rates that were similar to each other. Random-interval 120 s controlled the lowest rate in the immediate-reinforcement condition. Adding a constant 12-s delay to each of the first-component schedule parameters controlled lower response rates that did not vary systematically with reinforcement rate. The continuous and random-interval 60-s schedules of immediate reinforcement controlled higher global and first-component response rates than did the same schedules combined with longer delays, and first-component rates showed some graded effects of delay duration. In addition, the same schedules controlled higher second-component response rates in combination with a 1-s delay than in combination with longer delays. These results were related to those from previous studies on acquisition with delayed reinforcement as well as to those from similar reinforcement procedures used during steady-state responding.  相似文献   

3.
Social skills priming was used to increase the spontaneous social initiations of 2 socially withdrawn preschoolers, 1 of whom had been diagnosed with autism. During priming sessions, the teacher prompted and reinforced social behaviors (e.g., smiling, verbal initiations). We varied the rate of reinforcement during priming sessions and measured the effects of this manipulation on the rate of spontaneous social initiations during the subsequent classroom activity. Spontaneous initiations were more frequent after high rates of reinforcement than after low rates of reinforcement.  相似文献   

4.
This study describes the response profiles of a sample of isiXhosa learners regarding to the Adjusted Rorschach Comprehensive System (ARCS) and related influences to explain the response latencies. This was a multiple case study in which six test naive high school learners (females = 3; males = 3; aged 14 years) attempted to respond to the ARCS. Both test protocol and process data were gathered. Data were thematically analysed. Responses were adequate in 83% of the instances. Process factors that appeared to impact response rate and quality included language of administration, seating arrangement, and option to use drawing for the responses.  相似文献   

5.
The effects of automated cueing on teacher praise rate was investigated in one special, one fourth-, and one seventh-grade classroom. After establishing baseline praise rates in each of the three classrooms, two methods for increasing teacher praise rate were introduced according to a multiple-baseline design. During the first phase, two teachers were instructed to count and graph their praise rate during each session. All teachers received auditory cues to prompt praising during another phase. In all cases, introduction of cues markedly increased teacher praise rates, but self-recording was relatively ineffective. An analysis of teacher-praise distributions showed that cues closely controlled teacher praise for two of the three teachers.  相似文献   

6.
研究采用情绪图片观看任务,考察双耳乳突参考、全脑平均参考和参考电极标准化技术(Reference electrode standardization technique, REST)对情绪相关ERP成分在波幅、统计功效、内部一致性方面的影响,以及参考选择对ERP伪迹剔除率的影响。结果显示,双耳乳突参考下颞区EPN的波幅显著小于REST和全脑平均参考下的结果,而在顶区LPP上表现出完全相反的结果。此外,双耳乳突和全脑平均参考下更可能检测到P2上负性和中性图片波幅间的差异,而REST和全脑平均参考下更可能检测到EPN的“正性偏向”效应。未来研究应结合以往文献和特定成分谨慎选择参考类型。  相似文献   

7.
心理资本近年已成为研究大学生就业状况相关问题的热点之一.研究采用问卷调查法探讨了性别、生源地、专业、实习经验等因素对大学生心理资本的影响,以及两者对大学生就业成功率的影响.具体采用列联表分析、£检验、方差分析以及二元logistic回归分析分析了心理资本各维度与各因素对大学生就业成功率的影响,发现专业和实习经历对心理资本有显著影响,心理资本中的乐观维度对大学生就业成功率有显著影响;建议为了提高大学生就业成功率,学校应努力为大学生提供更多的实践机会,重视大学生的人文教育,营造乐观的文化氛围.  相似文献   

8.
The effects of eating on heart rate variability (HRV) differ between adults and newborns. This may reflect the impact of suckling on the overall psychophysiological and autonomic nervous system maturation. The purpose of the present study was to explore whether the reactions of HRV during feeding change towards the adult pattern during the first 6 months of life. In addition, the effects of non-nutritive and nutritive sucking on heart rate (HR) and HRV were compared. The participants were 23 infants on whom recordings were performed as newborns and at 6, 12 and 24 weeks old. Nutritive sucking caused an increase in HR and a decline in HRV. The results were consistent with previous reports of a decrease in high frequency components of HRV during feeding in newborns, reflecting a decrease in parasympathetic activity. This response was apparent in all four ages studied, and remained similar throughout the 6-month period. However, age as an independent factor seemed to influence both HR and HRV. Pacifier sucking had no significant effects on HRV at any age. The results demonstrate the physical strain that sucking imposes on the baby, with a specific autonomic nervous system response involved. We consider this response an essential part of the overall psychophysiological maturation of infants.  相似文献   

9.
The behavioral‐momentum model of resurgence predicts reinforcer rates within a resurgence preparation should have three effects on target behavior. First, higher reinforcer rates in baseline (Phase 1) produce more persistent target behavior during extinction plus alternative reinforcement. Second, higher rate alternative reinforcement during Phase 2 generates greater disruption of target responding during extinction. Finally, higher rates of either reinforcement source should produce greater responding when alternative reinforcement is suspended in Phase 3. Recent empirical reports have produced mixed results in terms of these predictions. Thus, the present experiment further examined reinforcer‐rate effects on persistence and resurgence. Rats pressed target levers for high‐rate or low‐rate variable‐interval food during Phase 1. In Phase 2, target‐lever pressing was extinguished, an alternative nose‐poke became available, and nose‐poking produced either high‐rate variable‐interval, low‐rate variable‐interval, or no (an extinction control) alternative reinforcement. Alternative reinforcement was suspended in Phase 3. For groups that received no alternative reinforcement, target‐lever pressing was less persistent following high‐rate than low‐rate Phase‐1 reinforcement. Target behavior was more persistent with low‐rate alternative reinforcement than with high‐rate alternative reinforcement or extinction alone. Finally, no differences in Phase‐3 responding were observed for groups that received either high‐rate or low‐rate alternative reinforcement, and resurgence occurred only following high‐rate alternative reinforcement. These findings are inconsistent with the momentum‐based model of resurgence. We conclude this model mischaracterizes the effects of reinforcer rates on persistence and resurgence of operant behavior.  相似文献   

10.
We report the study of the effect of strain rate on the compressive behaviour of a Zr56Al10.9Ni4.6Cu27.8Nb0.7 bulk metallic glass. The results indicated that both the strength and plasticity of the glass increase with increasing the strain rate up to 10?5 s?1, above which the strength and plasticity start to decrease. The enhanced mechanical properties under a strain rate of 10?5 s?1 are due to the emission/propagation rate of the shear bands being consistent with the strain rate.  相似文献   

11.
We review the conceptual and empirical literature on the relation between oral reading rate and reading comprehension. Three lines of conceptual analysis converge on this relation: (a) application of basic behavior analytic principles suggests that fluent decoding should produce better reading comprehension through direct and indirect relations, (b) behavior analytic understanding of the importance of the rate of behavior as developed by Skinner, Lindsley and Haughton implies that higher reading rate contributes to improved comprehension, and (c) cognitive theory of automaticity explicitly states that high rate reading sets the stage for effective comprehension. A wealth of correlational evidence indicates that reading rate and reading comprehension covary. These results have been replicated across elementary grades and across a variety of measures of reading comprehension. However, experimental analyses have not convincingly demonstrated a functional relation between the two. Experimental work has yielded results that are mixed at best. Examination of experimental design issues shows that although this is not a simple relation to investigate, behavior analysts can make major contributions to understanding the possible functional relation between reading rate and reading comprehension.  相似文献   

12.
This study aimed to examine the influence of the presence of a partner in terms of affiliation level and role on anxiety in a physically threatening situation.

In the first experiment, nine male subjects waited alone for the electric shock, and the other nine subjects waited with their partner.

In the second experiment, 36 female subjects were assigned to four experimental groups by the difference of the role of a partner (coactor or audience) and the affiliation level of a partner (friend or stranger), and subjects waited for the electric shock with their partner.

It was found that anxiety of subjects decreased when the partner was a coactor and/or a friend. It was suggested that these two functioned differently in anxiety reduction in a physically threatening situation.  相似文献   

13.
剖宫产率的过快增加已经成为了一个全球性的问题,不仅是一个医疗问题,而且是一个社会问题、伦理问题。与剖宫产率增高相关的因素是多方面的,本文重点探讨医源性因素对剖宫产率增高的影响,分析从医院及医生方面控制剖宫产率增高的措施。  相似文献   

14.
Leading theories of false memory predict that veridical and false recall of lists of semantically associated words can be dissociated by varying the presentation speed during study. Specifically, as presentation rate increases from milliseconds to seconds, veridical recall is predicted to increase monotonically while false recall is predicted to show a rapid rise and then a slow decrease—a pattern shown by McDermott and Watson (2001) in a study using immediate recall tests. In three experiments we tested the generality of the effects of rapid presentation rates on veridical and false memory. In Experiments 1 and 2 participants exhibited high levels of false recall on a delayed recall test, even for very fast stimulus onset asynchronies (SOA)—contrary to predictions from leading theories of false memory. When we switched to an immediate recall test in Experiment 3 we replicated the pattern predicted by the theories and observed by McDermott and Watson. Follow-up analyses further showed that the relative output position of false recalls is not affected by presentation rate, contrary to predictions from fuzzy trace theory. Implications for theories of false memory, including activation monitoring theory and fuzzy trace theory, are discussed.  相似文献   

15.
This research shows that the motivation to posses a desired characteristic (or to avoid an undesired one) results in self-perceptions that guide people’s use of base rate in the Lawyer–Engineer problem (Kahneman & Tversky, 1973). In four studies, participants induced to believe (or recall, Exp. 2) that a rational cognitive style is success-conducive (or an intuitive cognitive style failure-conducive) subsequently viewed themselves as more rational and relied more on base rate in their probability estimates than those induced to believe that a rational cognitive style is failure-conducive (or an intuitive cognitive style success-conducive). These findings show that the desired self had an influence on reasoning in the self-unrelated lawyer–engineer task, since the use of base rates was mediated by changes in participants’ perceptions of their own rationality. These findings therefore show that the desired self, through the working self-concept that it entails, constitutes another factor influencing people’s use of distinct modes of reasoning.  相似文献   

16.
This study examined cardiovascular effects of incentive value in men and women confronted with cognitive challenges that were more and less difficult to meet. Participants performed computer memory tasks varying in difficulty from low to high, with instructions that they could earn chances toward a $100 prize or $10 prize by attaining a 90% success rate. Analysis of cardiovascular responses assessed during work revealed an interaction between difficulty and incentive value for heart rate. Participants' heart rate responses were proportional to task difficulty and unaffected by incentive value in all conditions except for the most difficult one. Where difficulty was greatest, $100 participants showed relatively high heart rate responsiveness, whereas $10 participants showed low heart rate responsiveness. This heart rate finding corroborates and extends cardiovascular results from previous experiments, and lends further support to the view that cardiovascular responses will be proportional to incentive value only under some task conditions.  相似文献   

17.
通过三个实验考察材料特有的内在因素差异对学习判断及其孤立效应的影响,选取814名的高一学生作为被试,男女各半。实验一是探讨性质不同的孤立项目对学习判断及其孤立效应的影响;实验二是探讨层次差异不同的同质项目对学习判断及其孤立效应的影响;实验三是探讨孤立项目的序列位置对学习判断及其孤立效应的影响。结果表明:在不同材料中,材料的性质的差异越大,孤立效应越显著,证明了孤立材料的距离效应;在同质材料中,材料内部层次差异越大,孤立效应越显著,证明了孤立材料的幅度效应;在学习判断中,不管孤立项目的序列位置处于前位还是后位,都存在孤立效应,且材料中孤立项目的位置越靠后面,其孤立效应就越明显,证明了孤立材料的后位效应。  相似文献   

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20.
Zinc oxide (ZnO) nanoparticles have been synthesized by a microwave heating method. The resulting powders were annealed at temperatures from 400°C to 800°C for 4?h. The annealed powders were characterized in terms of their structural, morphological, and optical properties by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and room-temperature photoluminescence (PL) spectroscopy, respectively. The XRD patterns of the samples revealed the formation of phase-pure ZnO, apparently without any impurities. However, FT-IR spectra revealed the presence of carboxylate impurities, the signals of which disappear as the annealing temperatures are increased from 400°C to 800°C. SEM pictures showed increasing size ZnO nanoparticles with increase in annealing temperature. The powder annealed at 800°C is identified as hexagonal wurzite ZnO. The improved PL spectral performance of the ZnO powder correlates well with the improved crystalline quality of the nanoparticles, as revealed by the XRD and PL. Sharp ultraviolet (UV) band edge luminescence has been observed at 375?nm, which is suitable for application in UV light emitting devices. The results also showed that the excitation wavelength dependence of the luminescence arises from quantum confinement effects.  相似文献   

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