Deng-Maw Lu

Analysis and Nanomold Design for Aluminum Nanoimprinting

A nano-forging process based on the potential function of an embedded atom method (EAM) and mechanism, for pure aluminum samples, was studied using molecular dynamic (MD) simulation. The effects of forging temperature and velocity were evaluated in terms of molecular trajectory, internal energy, and a radial distribution function. The simulation results clearly show that the internal energy exerted by the workpiece during the forging process rises with a decrease of forging temperature, and an increase of forging velocity also raises the internal energy. During the forging process, a special atomic structure in the (011) and (011) slip planes was observed that represents the site of dislocation generation and growth nucleation. When severe plastic deformation occurs, the density of the workpiece changes. The forged workpiece has similar distributions of atomic density after loading at different forging temperatures and velocities.

The manufacture and characteristics analysis of electrospun tungsten trioxide nanofibers

Abstract In this study, the effects of calcination temperature on the characteristics of tungsten trioxide (WO3) nanofibers over time were explored. The objective being to observe the effects of calcination temperature and time of exposure on nanofibers when the voltage, work flow rate, and the pinhead used in the process were all fixed. The results showed that when the calcination temperature was increased to 550 °C, fiber structure was damaged. The nanofibers showed the selectivity about 9% at 360 ppm of ethanol gas. The response of ethanol will increase when the concentration increase.

Fabrication of antireflective polymer films with subwavelength structures using Roll to Roll Nanoimprint Lithography

Anti-reflection based on the mimicking of moth eye subwavelength structures (SWSs) has several advantages over conventionally used multilayer thin film antireflective coatings like broad angular and spectral responses, polarization insensitivity and improved stability. In this study, we present the low cost fabrication of moth eye based SWSs on flexible polyethylene terephthalate (PET) substrate using Roll-to-Roll Ultraviolet Nanoimprint Lithography (UV-NIL). We have used a novel method to create a roller mold with embedded nanopores that can be used for easy replication of SWSs without demolding issues. Pure aluminum foil was wrapped around an acrylic cylinder (Ø = 90mm) and a multistep anodizing and pore widening scheme was employed to create well-ordered and periodic anodized aluminum oxide (AAO) nanopores with different aspect ratios. Optical characterization of the antireflective PET film shows a transmittance over 92 %, an increase of 3% as compared to bare PET, while reflectance can be reduced from 5.3% to 0.09% in the range of visible light. It was observed that higher aspect ratio SWSs is more effective in reducing reflections at higher incident angles. Consequently, we have demonstrated an economically feasible method for fabricating large area polymer films that can be used to reduce light reflections which impose severe limitations on the performance of many optoelectronic devices like solar cells, photodetectors and flat display panels.

A Note on the Vibrations of Scanning Near-Field Optical Microscopy Probe

In this paper, the natural frequencies of a scanning near-field optical microscopy with a optical fiber probe were determined by using Laplace transform with respect to the spatial and time variable. Appling the variety of different parameters of the lateral and axial spring constants, the expressions of the natural frequencies of the system will be derived. A numerical example is presented and many results are obtained, and summarized as follows: (1) when the non-dimensional lateral spring constant increases, then the different natural frequencies at mid-location of the lateral spring become increasing, (2) the first natural frequency gets larger as the non-dimensional lateral spring constant becomes larger, (3) the first natural frequency increases when the probe length decreases, (4) the axial natural frequencies of the first to fifth mode become larger when the non-dimensional axial spring constant is more than the value about 0.09. The results of vibration analysis of the scanning near-field optical microscopy with a optical fiber probe is very important, and it can be applied to design a new type of cantilever probe system in the feature.

EXPLICIT EQUATIONS AND SPECIAL CASES OF THE BURMESTER CURVES FOR THE PPP-P CASE

This paper presents an analytic treatment to investigate the Burmester curves of the PPP-P case. Provided that an instant center associated with an inflection point and rotation angle of a coupler about a pole are specified, the explicit equations of Burmester curves for the PPP-P case are directly derived without any differential process. Because the explicit equations derived are of quadratic form, their geometric properties can be easily investigated. Six degenerated cases and three special cases of the Burmester curves for the PPP-P case are obtained. A design example is presented.