High-Chern-number and high-temperature quantum Hall effect without Landau levels

The quantum Hall effect (QHE) with quantized Hall resistance of h/νe² started the research on topological quantum states and laid the foundation of topology in physics. Since then, Haldane proposed the QHE without Landau levels, showing nonzero Chern number |C| = 1, which has been experimentally observed at relatively low temperatures. For emerging physics and low-power-consumption electronics, the key issues are how to increase the working temperature and realize high Chern numbers (C > 1). Here, we report the experimental discovery of high-Chern-number QHE (C = 2) without Landau levels and C = 1 Chern insulator state displaying a nearly quantized Hall resistance plateau above the Néel temperature in MnBi₂Te₄ devices. Our observations provide a new perspective on topological matter and open new avenues for exploration of exotic topological quantum states and topological phase transitions at higher temperatures.     

Structuring academic conflicts between majority and minority students: Hindrance or help to integration

The effects of two types of structured academic conflict, controversy and debate, were compared with individual study in a study on desegregation. Seventy-two sixth grade students were assigned to conditions on a stratified random basis controlling for sex, reading ability, and ethnic membership. In all three conditions students studied a controversial issue with materials representing both pro and con views. In the controversy condition each learning group was divided into two pairs representing the pro and con sides. In the debate condition each member of a learning group was assigned a pro or con position to represent in a debate with the other three members. In the individualistic condition subjects were told to learn the material without interacting with other students and each student was given all the pro and con materials. The results indicate that controversy promotes the most cross-ethnic verbal rehearsal and exchange of the assigned material, the most concern that all students master the assigned material, the most active search for more information about the topic being studied, the most reevaluation of one's position and incorporation of opponents' arguments, the most liking for the subject matter and the instructional experience, the highest self-esteem, and the most accepting and supportive relationships among minority and majority students. The debate condition generated higher levels of these dependent variables than did individualistic study.     

The A.M.I.G.O. project: A multicultural intergroup opportunity

This paper describes an empirical investigation of changes incurred as a result of participation in a semester-long intercultural experience. “The A.M.I.G.O. Project” is conducted in small group communication classes and requires students to meet and interact weekly with foreigners living in their community. The project is designed to allow college students to obtain some of the benefits of a foreign experience without going abroad. The program is also intended to provide a meaningful and worthwhile experience to individuals temporarily living in the U.S. A single-factor repeated measures analysis of variance was used to examine differences between participants and non-participants at the beginning and end of the semester. Five dependent variables-acceptance of differences, openness to new ideas, importance of foreign exchange, responsibility toward foreigners living in the community, and attitudes toward peace-were evaluated. The results of the questionnaire strongly indicate a significant change in the attitudes of the participants. Overall, students became more accepting of diversity and differences, felt greater responsibility to and increased importance of foreign visitors to the United States, and developed a sense of importance and desire for travel abroad. Furthermore, the members of the English as a Second Language class [the Amigos] demonstrated significantly greater improvement on their English proficiency exams than non-participants. Implications of the results and a discussion of the limitations of the study conclude with suggestions for future research.     

磁阻效应实验的设计

锑化铟既作霍尔元件测量了磁感应强度，又作磁敏电阻研究了其阻值随磁场的变化规律。不仅揭示了霍尔效应和磁阻效应在半导体内同时存在的事实，使产生2种物理现象的微观本质表现得更为突出，而且还消除了由于使用其他方法测量磁感应强度时，被测点与锑化铟所处位置不同而造成的系统误差。     

霍尔集成传感器的特性及其应用

详细地介绍了霍尔集成传感器内部结构、外形、输出特性、电气以及极限参数,并举例说明它的几方面应用.     

Giant magnetic field from moiré induced Berry phase in homobilayer semiconductors

When quasiparticles move in condensed matters, the texture of their internal quantum structure as a function of position and momentum can give rise to Berry phases that have profound effects on the material’s properties. Seminal examples include the anomalous Hall and spin Hall effects from the momentum-space Berry phases in homogeneous crystals. Here, we explore a conjugate form of the electron Berry phase arising from the moiré pattern: the texture of atomic configurations in real space. In homobilayer transition metal dichalcogenides, we show that the real-space Berry phase from moiré patterns manifests as a periodic magnetic field with magnitudes of up to hundreds of Tesla. This quantity distinguishes moiré patterns from different origins, which can have an identical potential landscape, but opposite quantized magnetic flux per supercell. For low-energy carriers, the homobilayer moirés realize topological flux lattices for the quantum-spin Hall effect. An interlayer bias can continuously tune the spatial profile of the moiré magnetic field, whereas the flux per supercell is a topological quantity that can only have a quantized jump observable at a moderate bias. We also reveal the important role of the non-Abelian Berry phase in shaping the energy landscape in small moiré patterns. Our work points to new possibilities to access ultra-high magnetic fields that can be tailored to the nanoscale by electrical and mechanical controls.     

The effect of cooperative and individualistic learning experiences on positive and negative cross-handicap relationships

The effects of cooperative and individualistic learning contingencies on interpersonal attraction, social acceptability, and self-esteem between handicapped and nonhandicapped fourth-grade students were tracked and compared. Sixty-nine students were assigned to conditions on a stratified random basis controlling for handicap, sex, and age. They participated in the study for 45 min a day for 54 instructional days during science class. Nonhandicapped peer ratings of the social acceptability of each handicapped student and several attitude measures were obtained four separate times at 18-day intervals. The results indicate that continued use of cooperative learning contingencies promote positive growth in interpersonal attraction, social acceptability, and self-esteem between handicapped and nonhandicapped students. The results also indicate that when cooperative learning contingencies are replaced with individualized learning contingencies, decay in the above-mentioned variables occurs.     

霍尔效应法测磁场的误差来源及消除分析

分析了霍耳效应法测磁场的误差来源，提出了为减少误差应采取的措施及注意事项．     

汽车传感器及其发展趋势

现代汽车中传感器已是无处不在,它是汽车电子控制系统的主要信息源,随着人们对汽车的稳定性、舒适性、安全性、节能性和环保性提出的更高需求,未来汽车传感器技术总的发展趋势是微型化、集约化和智能化。     

Reconciling Hall with discourse,written in the shadows of ‘“Confederate” and Rainbow Flags

ABSTRACT

This essay addresses Stuart Hall and discourse theory, focusing on his essay “Signification, representation, ideology.” Reflecting upon recent events involving representation and identity—US legalization of gay marriage, murders at a gay nightclub, removal of the “Rebel Flag” from the South Carolina state capitol, Donald Trump’s presidential campaign—I attempt to destabilize the counterproductive dualism of material/discourse in Hall’s critique of poststructural discourse theory. Finding amenability between Hall and Foucaultian discourse theory, I describe Hall’s utility for discourse scholars, such as his perspectives on ideological practices and generation of new discourses as an interventionist act.