CONTROLLING OF SCHOTTKY-BARRIER HEIGHTS FOR AU/N-GAAS AND TI/N-GAAS WITH HYDROGEN INTRODUCED AFTER METAL-DEPOSITION BY BIAS ANNEALING

Up to now, in most of the research work done on the effect of hydrogen on a Schottky barrier, the hydrogen was introduced into the semiconductor before metal deposition. This letter reports that hydrogen can be effectively introduced into the Schottky barriers (SBs) of Au/n-GaAs and Ti/n-GaAs by plasma hydrogen treatment (PHT) after metal deposition on [100] oriented n-GaAs substrates. The Schottky barrier height (SBH) of a SB containing hydrogen shows the zero/reverse bias annealing (ZBA/RBA) effect. ZBA makes the SBH decrease and RBA makes it increase. The variations in the SBHs are reversible. In order to obtain obvious ZBA/RBA effects, selection of the temperature for plasma hydrogen treatment is important, and it is indicated that 100-degrees-C for Au/n-GaAs and 150-degrees-C for Ti/n-GaAs are suitable temperatures. It is concluded from the analysis of experimental results that only the hydrogen located at or near the metal-semiconductor interface, rather than the hydrogen in the bulk of either the semiconductor or the metal, is responsible for the ZBA/RBA effect on SBH.

Footwear for Gender Recognition

Conventionally, biometrics resources, such as face, gait silhouette, footprint, and pressure, have been utilized in gender recognition systems. However, the acquisition and processing time of these biometrics data makes the analysis difficult. This letter demonstrates for the first time how effective the footwear appearance is for gender recognition as a biometrics resource. A footwear database is also established with reprehensive shoes (footwears). Preliminary experimental results suggest that footwear appearance is a promising resource for gender recognition. Moreover, it also has the potential to be used jointly with other developed biometrics resources to boost performance.

社会冲突信息加工的事件相关电位研究

Processing of discrepant information is an important part in our everyday life. According to the social attributes of information, it can be categorized into two parts: social discrepancy and nonsocial discrepant information. The researches focused on nonsocial discrepancy are much mature than those of social discrepancy processing. This serial study employed three ERP experiments to explore the attributes of social discrepancy cognition. Experiment one compared the ERP differences between social and nonsocial discrepancy processing, experiment two adopted single stimulus paradigm to explore the negativity attention biases of social emotions, experiment three investigated the affective mechanism of emotions to social discrepancy information with cue-target paradigm, based on the experiment one and two. We invited healthy undergraduates to participate in our researches, in which social gender words and affective images were stimuli to explore the temporal sequences, activated modes and affective mechanisms of social discrepancy. The results were as below: 1. The differences of attention resource distributions between social and nonsocial information processing exhibited as early as 200 ms, since which P2 was evoked in both blocks. The larger P2 in nonsocial block represented the more attention to physical and nonsocial attributes of objects. N300/400 indicated the differences of evaluating systems in each block. The cognitive mechanisms of social and nonsocial tasks were specific, based on the fact: (1) the discrepancy evaluating system was activated earlier in nonsocial block than that of social block; (2) the social cognition performed right hemisphere advantage, but nonsocial task did not so. 2. Social emotions also could raise a negativity bias on attention. The latency of P2 evoked by social sad images was shorter than that of social happiness and neutral images. The latencies of P2 indicated that sad emotions attracted attention earlier, and possessed a processing advantage. The phenomenon that the larger N2 was evoked by social sadness showed that people was easily moved by sad emotions and sympathized the sadness. 3. Emotions affected social discrepancy processing. Positive affective mood magnified the discrepancy effect, based on the smaller latencies of difference N400 and larger amplitudes. Persons with happy mood synthesized social stereotypes to accelerate the social tasks. 4. Three experiments all showed the right hemisphere advantages of social cognition and social emotions, offered more proof in laterality hypothesis of social cognition. Above all, social cognition had essential distinctions with nonsocial cognition; they two had their own specific characteristics. The fact that social cognition was prone to be affected by different emotional mood made it more complex.

中学生的性别—理科刻板印象及其影响因素

Gender stereotype has a great effect on an individual’s cognition and behavior. Notably, stereotyped cognition about gender and science exerts an influence on an individual’s academic or career choice. In order to weaken the negative effect of gender-science stereotype and facilitate girls’ participation in science, this study examined the development of implicit gender-science stereotype and influence factors with implicit association test and questionnaires in a sample of secondary school students. The present work showed that: Firstly, there were no gender differences and gender predominance in performance of math and physics during secondary school years. However, girls tended to attribute success in math and physics to unstable factors, or the failure to stable factors. The reverse was true for boys’ attribution. This gender difference in attribution was especially evident in their study of physics. Secondly, 7th to 11th grade students implicitly regarded science as male domain, with the exception of 7th grade boys, who thought both boys and girls can study science well. On the whole, this gender-science stereotype was more and more evident as the specialization of science subjects’ progresses through secondary school, and this inclination decreased with increasing grade. Thirdly, the negative correlation between explicit and implicit stereotype which appeared in girls from 8th grade grew stronger with increasing grade and became significant in 10th grade. On the contrary, the significantly positive correlation existed in 7th -11th boys. Fourthly, the experience including attitude toward science, science interests and self –efficacy in math and physics had significantly negative effect on girls’ implicit gender-science stereotype, and significantly positive effect on boys’. It was showed that gender moderated the effect of experience in the study of science and implicit gender-science stereotype, and the attitude toward science mediated the relationship between science interests, self-efficacy and implicit gender-science stereotype. Fifthly, the perceived teacher’s class behaviours by students and the perceived parents’ gender stereotype by children had strong predictive power on students’ implicit gender-science stereotype. And the perceived teachers’ and parents’ performance expectancies can influence gender-science stereotype indirectly through self-efficacy in related subjects and attitude toward science. In conclusion, the present study showed that cognitive bias about gender and science existed in Chinese secondary school students. The information conveyed from teachers and parents interacting with students’ experience in the study of science affect the formation of stereotyped cognition.