Neutron and X-ray diffraction studies and cohesive interface model of the fatigue crack deformation behavior

The crack-tip deformation behavior during a single overload, fatigue test of ferritic stainless steel, and Ni-based HAYNES 230 superalloy is studied at different structural levels using (1) neutron-diffraction, from which both the elastic-lattice strain and volume-averaged total dislocation densities are obtained, (2) polychromatic X-ray microdiffraction to probe the geometrically necessary dislocations and boundaries distribution, and (3) an irreversible and hysteretic cohesive interface model which has been implemented into a finite element framework to simulate the stress/strain evolution near the fatigue crack tip. Neutron strain measurements and finite element simulations are in qualitative agreement on the macroscopic length scale. Large plastic deformation induced by the overload and the resulting compressive residual strains are observed in front of the crack tip after the overload, and are the principal reason for the fatigue-crack-growth retardation. Strong strain gradients surrounding the crack propagation result in the formation of a high density of geometrically necessary dislocations near the fractured surface and cause local lattice rotations on the submicron level.     

Sol-gel-hydrothermal growth of oxide thin films at low temperatures

Lead zirconate titanate (PZT) (Pb(Zr_0.52Ti_0.48)O₃) and barium titanate (BaTiO₃) thin films have been successfully prepared using a novel sol-gel- hydrothermal (SG-HT) technique at low temperatures, which involves a combination of the conventional sol-gel process and a hydrothermal method. Highly (111)-oriented PZT thin films with a single perovskite phase and polycrystalline BaTiO thin films with well developed crystallites were obtained at a processing temperature as low as 160⁰C. The microstructural characteristics demonstrate that the SG-HT-derived PZT and BaTiO₃ thin films with good crystallinity and surface morphology are converted from the amorphous phase to the desired perovskite phase on platinum-coated and bare silicon substrates at a low processing temperature of 100-200 C. These results suggest that the SGHT technique, which is of great significance because of its low processing temperature, will become a potential and promising process for fabricating PZT, BaTiO₃ and other oxide thin films.     

“Too Asian?” or the Invisible Citizen on the Other Side of the Nation?

In November 2010, Maclean’s magazine published a provocative article “Too Asian?” which aroused hot debate and critique from various social groups. However, its racist nature and the role of media in reinforcing racial stereotypes, manufacturing consent, and naturalizing unequal power relations has not been examined in a systematic way. Using critical discourse analysis, this paper aims to reveal its ideological and hegemonic function in constructing unequal social identities and social relations which consequently prevents racialized minorities from accessing post-secondary educational opportunities. Four themes are identified and discussed here. First, the “Too Asian?” article reinforces an Us/Them division and a “forever foreigner” identity of racialized minorities. Second, it essentializes ethnic culture and identifies culture rather than structural constraints as an explanation for individual social behaviors. Third, it represents “Asian” students as self-segregationists who should be blamed for their own exclusion. Last, but most important, it aims to justify white privilege in the field of post-secondary education by questioning the idea of meritocracy as university admission criteria and suggests maintaining “WASP Credentials.”     

Need Satisfaction Supportive Game Features as Motivational Determinants: An Experimental Study of a Self-Determination Theory Guided Exergame

Empirical studies have validated that basic needs satisfaction supported by video game play predicts motivation and engagement outcomes. However, few studies specifically manipulated game features for each of the three basic needs specified in the self-determination theory (SDT) to examine how the game features impact players' need satisfaction and game experience. The current study employed an in-house developed exergame and manipulated the game features in a 2 (autonomy-supportive game features: on vs. off) × 2 (competence-supportive game features: on vs. off) experiment to predict need satisfaction, game enjoyment, motivation for future play, effort for gameplay, self-efficacy for exercise using the game, likelihood of game recommendation, and game rating. The manipulated game features led to the corresponding need satisfaction. Manipulated autonomy-supportive and competence-supportive game features had main effects on most motivation and engagement outcomes. Need satisfaction of autonomy and need satisfaction of competence were both found to be mediators for the relationships between the game features and the motivation and engagement outcomes. The findings add evidence to support the underlying mechanism postulated by SDT for media enjoyment and motivation as well as the emerging entertainment research conceptualizing enjoyment as need satisfaction. The findings also have practical implications for intervention effort that intends to capitalize the motivational pull of video games.     

Can Toddlers Learn Vocabulary from Television? An Experimental Approach

This study was inspired by the rise in television targeting toddlers and preverbal infants (e.g., Teletubbies, Baby Mozart). Overall, we investigated if very young children who are in the early stages of language acquisition can learn vocabulary quickly (fast map) from television programs. Using a fast mapping paradigm, this study examined a group (n = 48) of toddlers (15–24 months) and their ability to learn novel words. Utilizing a repeated measures design, we compared children's ability to learn various novel words in 5 different conditions. These included the presentation and identification of a novel word by an adult speaker via live presentation when the toddler was attending (i.e., joint reference), an adult via live presentation when the toddler was not attending, an adult speaker on television, and an edited clip from a children's television program (Teletubbies). Overall, the toddlers were most successful in learning novel words in the joint reference condition. They were significantly less successful in the children's program condition. Furthermore, there was a significant interaction between age and condition on children's performance. Both younger (15–21 months) and older (22–24 months) participants identified the target objects when they were taught the novel word by an adult speaker; however, it appeared that children under the age of 22 months did not identify the target item when they were taught the novel word via the television program.     

Electroencephalography when meditation advances: a case-based time-series analysis

Increased alpha and theta activities in electroencephalography (EEG) have been found during various forms of meditation. However, advanced stage of meditation drew less attention to date. We aimed at exploring EEG characteristics during advanced meditation. Bilateral absolute alpha and theta EEG powers were recorded when a single meditator at rest, exercising breath meditation, and reaching the advanced meditative stage in 10 sessions of meditation. Averaged time-series data were analyzed using simulation modeling analysis to compare the powers during different meditative phases. During breath meditation, significantly higher activities compared with baseline were found only in bilateral theta (P = 0.0406, 0.0158 for left and right sides, respectively), but not in alpha (P = 0.1412, 0.0978 for left and right sides, respectively) bands. When meditation advanced, significantly increased activities were found both in bilateral alpha (P = 0.0218, 0.0258 for left and right sides, respectively) and theta (P = 0.0308, 0.0260 for left and right sides, respectively) bands compared against breath meditation. When advanced meditation compared against baseline, bilateral alpha (P = 0.0001, 0.0001 for left and right sides, respectively) and theta (P = 0.0001, 0.0001 for left and right sides, respectively) bands revealed significantly increased activities. Our findings support that internalized attention manifested as theta activity continuingly enhances significantly in sequential phases of meditation, while relaxation manifested as alpha activity is significant only after the advanced meditative phase is reached.     

The cognitive advantage for one’s own name is not simply familiarity: An eye-tracking study

Eye-tracking technique and visual search task were employed to examine the cognitive advantage for one’s own name and the possible effect of familiarity on this advantage. The results showed that fewer saccades and an earlier start time of first fixations on the target were associated with trials in which participants were asked to search for their own name, as compared to search for personally familiar or famous names. In addition, the results also demonstrated faster response times and higher accuracy in the former kind of trials. Taken together, these findings provide important evidence that one’s own name has the potential to capture attention and that familiarity cannot account for this advantage.     

Play it again: neural responses to reunion with excluders predicted by attachment patterns

Reunion behavior following stressful separations from caregivers is often considered the single most sensitive clue to infant attachment patterns. Extending these ideas to middle childhood/early adolescence, we examined participants' neural responses to reunion with peers who had previously excluded them. We recorded event‐related potentials among nineteen 11‐ to 15‐year‐old youth previously classified on attachment interviews (11 secure and 8 insecure‐dismissing) while they played a virtual ball‐toss game (Cyberball) with peers that involved fair play, exclusion and reunion phases. Compared to secure participants, dismissing participants displayed a greater increment in the N2 during reunion relative to fair play, a neural marker commonly linked to expectancy violation. These data suggest a greater tendency toward continued expectations of rejection among dismissing children, even after cessation of social exclusion. In turn, the link between self‐reported ostracism distress and neural signs of negative expectancy at reunion was moderated by attachment, such that self‐reports were discordant with the neural index of expectancy violation for dismissing, but not for secure children. A video abstract of this article can be viewed at http://www.youtube.com/watch?v=qzoRel5c-4s .     

The Psychological Displacement Paradigm in Diary-Writing (PDPD) and its Psychological Benefits

The present study aimed to investigate the psychological displacement paradigm in diary-writing (PDPD) had both immediate and short-term psychological benefits. Participants were randomly assigned to write about their recent negative life experiences two times a week for 2 weeks in PDPD group or comparison group. Results revealed that the PDPD group displayed a decrease in negative emotion and an increase in positive emotion immediately after each writing session; they also showed an increase in psychological well-being relative to the comparison group for at least 2 weeks. Implications for PDPD are discussed.     

大鱼小池效应研究回顾及展望

大鱼小池效应(Big Fish Little Pond Effect)是解释不同教育情境中学生自我概念水平的一个特定概念,Marsh将其定义为：能力同等的学生,在平均成绩较高的学校或班级里的学业自我概念较低,而在平均成绩较低的学校或班级则学业自我概念会较高。大鱼小池效应包括学生采用概括他人和特定他人的比较标准所分别产生的同化效应和对比效应,社会比较对学业自我概念形成具有特定影响。大鱼小池效应的未来研究可以从研究方法的改进、调节变量的控制和跨文化比较等方面拓展。