Optimization of Thin-Film Winding Conditions Considering Viscoelastic Property and Thickness Variation and its Experimental Verification

Plastic films are produced using roll-to-roll systems, which allow the film to be wound into a roll and stored in a small space. Roll defects, however, can cause significant economic loss, and gage bands remain an open area of research. More recently, plastic films have become thinner, so we must now reconsider wrinkling and slippage, problems which depend on the in-roll stress condition. Therefore, predicting the stress condition is essential to preventing defects occurring in wound rolls. In addition, the in-roll stress will change over time as a result of viscoelastic properties. This study theoretically investigates and experimentally verifies winding condition optimization and in-roll stress in consideration of the viscoelastic property and web thickness profile at a constant rewinding tension. Results show that the predicted values are in agreement with the measured values.

Groove Shape Optimization of Thrust Air Bearing for Small Size Spindle Considering the Processing Errors

In this research, we aim to examine the usefulness of the newly developed spindle motor proposed by Ochiai. Since machining error due to tool wear etc. used for microfabrication can be ignored, laser processing was used as a processing method. Thrust bearing grooves were generated by laser processing, and variation in groove depth was observed. Finally, the optimum shape of the thrust bearing groove was obtained by robust optimization using the probability distribution that can be approximated from the obtained machining error.

Design of Mechaless LiDAR Optical System With Large FOV Using Liquid Lens and Fisheye Lens

Mechaless LiDAR technology, which does not have a mechanical drive part, has been actively studied in order to increase the reliability of the LiDAR device at low cost and drive environment in order to more actively apply LiDAR technology to autonomous driving. Mechaless LiDAR technology, which has been mainly studied recently, includes 3D Flash LiDAR technology, MEMS mirror utilization method, and OPA (Optical Phased Array). However, these methods have not been developed rapidly as a key technology for achieving autonomous driving due to low stability of driving environment or remarkably low measurable distance and FOV (field of view) compared with mechanical LiDAR. In this study, we investigated the improvement of FOV by using a flux-deflecting liquid lens and a fisheye lens that can achieve fine spatial resolution through continuous voltage regulation. Based on the initial design results, it was examined that the FOV can be secured to 80 ° or more by utilizing a relatively simple fisheye lens composed of only spherical lenses.

Simulating Surface Forces Between Iron Oxide Surfaces Immersed in Methyl Oleate Using Molecular Dynamics

Using Molecular Dynamics (MD) simulation, the current study determined the surface forces between iron oxide surfaces when immersed in methyl oleate. Condensed-phase Optimized Molecular Potentials for Atomistic Simulation Studies (COMPASS) force field was used to model the methyl oleate molecules. For the nano-confinement simulation, the iron oxide wall was modelled from its crystal structure. The nano-confinement simulation model was setup in a manner where the confined methyl oleate molecules were in contact with the bulk molecules surrounding each side of the iron oxide walls. Through the simulation, the load-separation gap profile was obtained by reducing the separation gap between the ferric oxide walls. When the separation gap was reduced from 2.75 nm to 1.88 nm, the load is shown to increase monotonically. Such increase in load bearing ability of the contact is observed to correspond to a more densely packed methyl oleate molecules, reflected by four well-formed layers across the separation gap. As the gap is dropped from 1.88 nm to 1.63 nm, the load instead reduces, indicating deteriorating load bearing ability of the contact. However, the load bearing ability of the contact is then shown to recover when the gap was further reduced till 1.38 nm. This oscillatory load trend is shown to be as a result of a layer of methyl oleate molecules being squeezed out of contact, corroborated by the density profile change where four well-formed layers were reduced to only three layers from 1.88 nm to 1.38 nm gap. This also indicates that the simulated contact exhibits structural forces, known as solvation forces. Thus, the MD simulation discussed in this study is demonstrated to be capable of providing a foundation to allow for a multi-scale simulation, integrating various force laws at different length scales, to study larger scale tribological contacts.

Stress Distributions in an Elastic Body due to Molecular Interactions Considering One-Dimensional Periodic Material Distribution Based on Mindlin Solution

A method to calculate the stress distributions in the elastic body caused by the molecular interactions has been established. The stress distribution was calculated based on the Mindlin’s solution considering the one-dimensional periodic material distribution. The calculation results for a distribution of two materials were presented. The basic characteristics of the stress distribution in the elastic body were quantitatively clarified.

MEMS-Based Micro Probe Incorporating Electrostatic Actuator Towards Friction Force Microscopy With Accurate Gap Control

Lubrication in nanometer-sliding gaps has attracted much interest along with the advance of processing technology. To clarify the lubrication phenomena in nanometer gaps, force measurement under accurate control of the gap between the sliding probe and sample surface is needed because the lubrication properties significantly depend on the gap size. In this paper, we aimed at realizing friction force microscopes that is capable of accurate control of sliding gap. A probe with an actuator that utilizes electrostatic force was proposed and its feasibility was demonstrated.

Detection of Directivity of Fluorescence From a Mixed Specimen Which Consists of Micro Particles Attached Different Fluorescent Substances Using a Light Waveguide Incorporated Optical TAS

A resin-based optical total analysis system (O-TAS) which consists both of microfluidic channels and light waveguides [1] is thought to be one of the most promising components in developing a “ubiquitous human healthcare system” in the near future. Along with this technology trend, we have already developed a transparent epoxy-resin-based optical TAS chip which has a specially prepared light waveguide structure of radially arranged configuration at an intersection portion with a microfluidic channel, in order to detect directivity of fluorescence from fluorescent substance attached micro particles [2],[3]. Schematic diagram of the optical TAS is shown in Figure 1. In the latest research, utilizing an AC modulated laser source and time-series averaging function on detected signal waveforms, we could have successfully obtained directivities of fluorescence from 5-μm-diameter particles with higher signal to noise (S/N) ratio [3].

Low-Power and Reference-Less Data and Clock Recovery Circuit for Visible Light Receivers

In this paper a low power all-digital clock and data recovery (ADCDR) with 1Mhz frequency has been proposed. The proposed circuit is designed for optical receiver circuit on the battery-less photovoltaic IoT (Internet of Things) tags. The conventional RF receiver has been replaced by the visible light optical receiver for battery-less IoT tags. With this proposed ADCDR a low voltage, low power consumption & tiny IoT tags can be fabricated. The proposed circuit achieve the maximum bandwidth of 1MHz, which is compatible with the commercial available LED and light sensor. The proposed circuit has been fabricated in TSMC 0.18um 1P6M standard CMOS process. Experimental results show that the power consumption of the optical receiver is approximately 5.58uW with a supply voltage of 1V and the data rate achieves 1Mbit/s. The lock time of the ADCDR is 0.893ms with 3.31ns RMS jitter period.

A Highly Efficient and Adaptable Solar-Energy Harvesting Circuit for Batteryless IoT Devices

In this paper a new on-chip 2nd generation solar energy harvesting DC-DC converter has been proposed for a battery-less Internet of Things (IoTs) Devices. The propose circuit is design to maximize the transfer efficiency and stability as well as enough high power supply to the back-end loads. Altogether the proposed circuit consists of a cross-coupled charge pump, a maximum power point tracking (MPPT) circuit, a timing control circuit and regulator. The range of input voltage is from 0.5V to 3V. Required boosted output voltage is in the range of 1V to 3.3V. The maximum transfer efficiency is more than 60% and the maximum throughout power is 200μW. A gated clock frequency modulation circuit has been designed and employed in the maximum power point tracking (MPPT) unit to lock the input resistance of the charge pump. In addition, to provide a stable voltage to the load a low dropout (LDO) regulator circuit is used. The experimental results show that the maximum power conversion efficiency (PCE) is 78% at 52μW input power condition.

Thermo-Molecular Gas-Film Lubrication (t-MGL) Considering Temperature Distributions and Accommodation Coefficients: Analyses by Quasi-Free-Molecular t-MGL Equation

In the present paper, the flying characteristics of a step slider flying in either air or He with a local temperature distribution of the disk are analyzed using the thermo-molecular gas-film lubrication (t-MGL) equation in the quasi-free-molecular flow region (quasi-free-molecular t-MGL equation: t-MGLqfm eq.). The gas temperature in the t-MGLqfm equation, τG, is assumed to be that in the free molecular limit, τGfm, defined by temperatures and accommodation coefficients at the disk, τW0, α0, and those at the slider, τW1, α1, respectively. The decreases in static spacing for the slider flying in He are significant. Moreover, the spacing decreases as the accommodation coefficients of the disk, α0, decreases, that is, as the ratio of specular reflection increases. The spacing fluctuation caused by a running wavy disk varies according to both the ambient gas (air/He) and the boundary accommodation coefficients.