Batch Transfer Printing of Small-Size Silicon Nano-Films with Flat Stamp

Silicon nano-film is essential for the rapidly developing fields of nanoscience and flexible electronics, due to its compatibility with the CMOS process. Viscoelastic PDMS material can adhere to Si, SiO2, and other materials via intermolecular force and play a key role in flexible electronic devices. Researchers have studied many methods of transfer printing silicon nano-films based on PDMS stamps with pyramid microstructures. However, only large-scale transfer printing processes of silicon nano-films with line widths above 20 μm have been reported, mainly because the distribution of pyramid microstructures proposes a request on the size of silicon nano-films. In this paper, The PDMS base to the curing agent ratio affects the adhesion to silicon and enables the transfer, without the need for secondary alignment photolithography, and a flat stamp has been used during the transfer printing, with no requirement for the attaching pressure and detaching speed. Transfer printing of 20 μm wide structures has been realized, while the success rate is 99.3%. The progress is promising in the development of miniature flexible sensors, especially flexible hydrophone.

Application of Virtual Reality in Chemical Education Using Intermolecular Force Display System HaptiChem

Virtual reality technology has been recently more intensively applied in chemistry. HaptiChem, which was developed in 2006, is one of the systems appeared in the early stage of this field. It is an intermolecular force display system, which makes it possible to touch and move molecules as feeling intermolecular force in a three-dimensional virtual space by using a haptic device. The functions and graphic display were designed as simple as possible for educational use, so that learner can easily grasp the meaning of the concept of molecular forces. We introduced HaptiChem in chemical education. We held a high school chemistry class with 43 students entitled “Several Forces between Molecules” as being open to the media. The students learned about intermolecular force from a lecture together with experiences of the force using HaptiChem. They asked more questions about intermolecular force during the class than usual. Their answers to the questionnaires after the class indicated that the haptic system promoted curiosity and enhanced learning. The students could learn more effectively by combining with the active feeling with HaptiChem. The high-school teachers evaluated that such a system can more efficiently encourage students to learn and remember things by stimulating their sense of touch. The observations also suggested that a haptic device made it easier to establish three-dimensional perception, which is difficult only with 2D-display. This pilot experiment was performed on 15th March 2007. It was the first attempt at using it in the field of chemical education. The observation was done fourteen years ago. However, since the effectiveness of haptic device in chemical education has not been changed and the interests of the applications have been increased, we decided to report the data we observed, which should be still worth disclosing. We wish to dedicate the results to new developments now and in the future.

Application of Virtual Reality in Chemical Education Using Intermolecular Force Display System HaptiChem

Virtual reality technology has been recently more intensively applied in chemistry. HaptiChem, which was developed in 2006, is one of the systems appeared in the early stage of this field. It is an intermolecular force display system, which makes it possible to touch and move molecules as feeling intermolecular force in a three-dimensional virtual space by using a haptic device. We introduced HaptiChem in chemical education. We held a high school chemistry class with 43 students entitled “Several Forces between Molecules” as being open to the media. The students learned about intermolecular force from a lecture together with experiences of the force using HaptiChem. They asked more questions about intermolecular force during the class than usual. Their answers to the questionnaires after the class indicated that the haptic system promoted curiosity and enhanced learning. The students could learn more effectively by combining with the active feeling with HaptiChem. The high-school teachers evaluated that such a system can more efficiently encourage students to learn and remember things by stimulating their sense of touch. The observations also suggested that a haptic device made it easier to establish three-dimensional perception, which is difficult only with 2D-display. This pilot experiment was performed on 15th March 2007. It was the first attempt at using it in the field of chemical education. The observation was done fourteen years ago. However, since the effectiveness of haptic device in chemical education has not been changed and the interests of the applications have been increased, we decided to report the data we observed, which should be still worth disclosing. We wish to dedicate the results to new developments now and in the future.

Particle entrapment in elliptical, elastohydrodynamic, rough contacts and the influence of intermolecular (van der Waals) forces

The entrapment/rejection process of spherical, rigid microparticles in elliptical, rough elastohydrodynamic contacts is modelled. An earlier model of the author is extended to include van der Waals intermolecular forces, in addition to mechanical (reaction and friction) and fluid–particle forces. Surface roughness effects are also introduced in terms of the intermolecular force formulation and in the microscale friction (particle–asperity) sub-model. Possibilities related to particle entry into a contact are quantified by weight factors and performance indices. A total entrapment index is defined and linked to the probability of particle entrapment. A parametric analysis investigates the effect of the intermolecular particle force on the entrapment probability by varying the contact load, lubricant viscosity, elastic modulus of the contacting solids, contact velocity and the macroscopic (Coulomb) coefficient of friction.