Enhancing User Experience of Eye-Controlled Systems: Design Recommendations on the Optimal Size, Distance and Shape of Interactive Components from the Perspective of Peripheral Vision.

For special populations with motor impairments, eye-controlled interaction may be the only way for them to communicate with the outside world. Because of the dominance of vision in the motor mechanism, eye-controlled interaction has high usability and important research value. During eye-controlled interaction, the visual channel needs to receive information from the graphical user interface (GUI) and transmit the user's eye-controlled instructions, which overburdens the visual channel and reduces the efficiency of eye-controlled interaction. This study presents an ergonomic experiment to study how to design interactive GUI components in an eye-controlled user interface. The experiments were conducted based on the shape, size, and distance (from the object to the center of the screen) of the visual interactive components. The experiment comprised three parts: (1) the pre-experiment determined the evaluation index and selected the icon material; (2) the formal experiment was a three-factor within-subjects experiment, which included a search task using participants' peripheral vision; and (3) after the experiment, subjective evaluations were conducted using a questionnaire. The results showed that the shape, size, and distance of the interactive object significantly affected the reaction time, and the size factor significantly affected the movement time of the eye-controlled interaction. Finally, combined with the results of the subjective evaluation, we concluded that the recommended sizes of the interactive components were 2.889°, 3.389°, and 3.889°, and the recommended distances were 5.966° and 8.609°. Additionally, designers should utilize components with simple concrete shapes as much as possible to improve user recognition efficiency. Our study provides enlightening recommendations on how to design components in eye-controlled interactive interfaces, and has great guiding significance for building design standards of the eye-controlled systems.

Current instability of carbon nanotube field effect transistors.

The current instability of carbon nanotube field effect transistors (CNTFETs) is systematically studied under the influence of applied voltages, surfactants and temperatures. The devices were fabricated from carbon nanotubes and sodium dodecyl benzene sulfonate (SDBS) suspension using an ac dielectrophoresis (DEP) technique. The source and drain current for as-prepared p-type CNTFETs show an increase with time for the on-state, but a decrease for the off-state. Comparisons between constant and intermittent biasing conditions reveal that mobile ions could be the origin of the current instability. After removal of adsorbed SDBS, opposite transient behaviors of the current were observed, which can be attributed to the charge trapping induced screening effect.