Sensitive, Robust, Wide-Range, and High-Consistency Capacitive Tactile Sensors with Ordered Porous Dielectric Microstructures.

Flexible capacitive tactile sensors show great promise in personalized healthcare monitoring and human-machine interfaces, but their practical application is normally hindered because they rarely possess the required comprehensive performance, that is, high pressure sensitivity and fast response within a broad pressure range, high structure robustness, performance consistency, etc. This paper aims to engineer flexible capacitive pressure sensors with highly ordered porous dielectric microstructures and a 3D-printing-based fully solution-processable fabrication process. The proposed dielectric layer with uniformly distributed interior microporous can not only increase its compressibility and dynamic response within an extended pressure range but also enlarge its contact area with electrodes, contributing to a simultaneous improvement in the sensitivity, response speed, detection range, and structure robustness. Meanwhile, owing to its superior abilities in complex structure manufacturing and dimension controlling, the proposed 3D-printing-based fabrication process enables the consistent fabrication of the porous microstructure and thus guarantees device consistency. As a result, the prepared pressure sensors exhibit a high sensitivity of 0.21 kPa-1, fast response and relaxation times of 112 and 152 ms, an interface bonding strength of more than 455.2 kPa, and excellent performance consistency (≤5.47% deviation among different batches of sensors) and tunability. Encouraged by this, the pressure sensor is further integrated with a wireless readout circuit and realizes wireless wearable monitoring of various biosignals (pulse waves and heart rate) and body movements (from slight finger touch to large knee bending). Finally, the influence law of the feature parameters of the porous microstructure on device performance is established by the finite element method, paving the way for sensor optimization. This study motivates the development of flexible capacitive pressure sensors toward practical application.

Self-Healing Hydrogel Bioelectronics.

Hydrogels have emerged as powerful building blocks to develop various soft bioelectronics because of their tissue-like mechanical properties, superior bio-compatibility, the ability to conduct both electrons and ions, and multiple stimuli-responsiveness. However, hydrogels are vulnerable to mechanical damage, which limits their usage in developing durable hydrogel-based bioelectronics. Self-healing hydrogels aim to endow bioelectronics with the property of repairing specific functions after mechanical failure, thus improving their durability, reliability, and longevity. This review discusses recent advances in self-healing hydrogels, from the self-healing mechanisms, material chemistry, and strategies for multiple properties improvement of hydrogel materials, to the design, fabrication, and applications of various hydrogel-based bioelectronics, including wearable physical and biochemical sensors, supercapacitors, flexible display devices, triboelectric nanogenerators (TENGs), implantable bioelectronics, etc. Furthermore, the persisting challenges hampering the development of self-healing hydrogel bioelectronics and their prospects are proposed. This review is expected to expedite the research and applications of self-healing hydrogels for various self-healing bioelectronics.

The relationship between social media and professional learning from the perspective of pre-service teachers: A survey.

Social media usage is indispensable for college students, but the connection between social media and learning has received little scientific investigation. By examining pre-service teachers' attention to science, technology, engineering, and mathematics (STEM) teaching content and presentation in social media apps through WeChat, DingTalk, and TikTok, this study aimed to provide suggestions on using social media apps to promote pre-service teachers' skill learning and teaching development and to understand the relationship between social media and learning. 383 valid surveys were distributed and gathered. The findings indicate that: 1) Social media apps have both beneficial and detrimental effects on education. 2) The degree of agreement differs on "Social media app is an excellent teaching tool" and "social media app has significant promise in boosting educational development". The highest and lowest levels of agreement degrees were obtained for DingTalk and TikTok. The level of identification also affects how much pre-service teachers may pay attention to educational research and how frequently they study new materials in the future. 3) The degree to which pre-service teachers' academic performance in professional learning is affected by their use of social media varies. These findings have implications for pre-service teachers. This study suggests that it is necessary to further investigate the teaching aid function of social media apps and how pre-service teachers can better utilize them to develop professional skills.

Visual analysis of commognitive conflict in collaborative problem solving in classrooms.

In today's knowledge-intensive and digital society, collaborative problem-solving (CPS) is considered a critical skill for students to develop. Moreover, international education research has embraced a new paradigm of communication-focused inquiry, and the commognitive theory helps enhance the understanding of CPS work. This paper aims to enhance the CPS skills by identifying, diagnosing, and visualizing commognitive conflicts during the CPS process, thereby fostering a learning-oriented innovative approach and even giving the script of technology-assisted feedback practices. Specifically, we utilized open-ended mathematical tasks and multi-camera video recordings to analyze the commognitive conflicts in CPS among 32 pairs, comprising 64 Year 7 students. After selecting the high-quality, medium-quality, and low-quality student pairs based on the SOLO theory, further investigations were made in the discourse diagnosis and visual analysis for the knowledge dimensions of commognitive conflict. Finally, it was discovered that there is a need to encourage students to focus on and resolve commognitive conflicts while providing timely feedback. Visual studies of commognitive conflict can empower AI-assisted teaching, and the intelligent diagnosis and visual analysis of CPS provide innovative solutions for teaching feedback.

Visualizing Commognitive Responsibility Shift in Collaborative Problem-Solving During Computer-Supported One-to-One Math Tutoring.

The aim of this study is to use a commognitive responsibility framework to visualize responsibility shift in collaborative problem solving (CPS) during computer-supported one-to-one tutoring. Commognitive responsibility shift means that individuals' cognitive responsibility shift can be reflected by the discourse in communication. For our sample, we chose a 15-year-old Chinese boy and his mathematics teacher with 6 years of teaching experience, both of whom have experienced computer-supported learning and teaching mathematics, respectively. We collected four tutoring videos (each 60-90 min; in total, more than 330 min) online, and a 45-min interview video from the teacher. We found that the third type of commognitive responsibility shift in both the teacher's and student's CPS behavior online is not only teacher-student comparison but also alternating-led, which includes teacher-student-led (TS) and student-teacher-led (ST).

MagicChem: a MR system based on needs theory for chemical experiments.

Real chemical experiments may be dangerous or pollute the environment; meanwhile, the preparation of drugs and reagents is time-consuming. Due to the above-mentioned reasons, few experiments can be actually operated by students, which is not conducive to the chemistry learning and the phenomena principle understanding. Recently, due to the impact of Covid-19, many schools adopt online teaching, which is even more detrimental to students' learning of chemistry. Fortunately, MR(mixed reality) technology provides us with the possibility of solving the safety issues and breaking the space-time constraints, while the theory of human needs (Maslow's hierarchical needs) provides us with a way to design a comfortable and stimulant MR system with realistic visual presentation and interaction. The paper combines with the theory of human needs to propose a new needs model for virtual experiment. Based on this needs model, we design and develop a comprehensive MR system called MagicChem, which offers a robust 6-DoF interactive and illumination consistent experimental space with virtual-real occlusion, supporting realistic visual interaction, tangible interaction, gesture interaction with touching, voice interaction, temperature interaction, olfactory interaction and virtual human interaction. User study shows that MagicChem satisfies the needs model better than other MR experimental environments that partially meet the needs model. In addition, we explore the application of the needs model in VR environment. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10055-021-00560-z.