Recent Advances In Silicon Carbide Chemical Mechanical Polishing Technologies.

Chemical mechanical polishing (CMP) is a well-known technology that can produce surfaces with outstanding global planarization without subsurface damage. A good CMP process for Silicon Carbide (SiC) requires a balanced interaction between SiC surface oxidation and the oxide layer removal. The oxidants in the CMP slurry control the surface oxidation efficiency, while the polishing mechanical force comes from the abrasive particles in the CMP slurry and the pad asperity, which is attributed to the unique pad structure and diamond conditioning.

Copper-to-copper direct bonding on highly (111)-oriented nanotwinned copper in no-vacuum ambient.

A vacuum-free Cu-to-Cu direct bonding by using (111)-oriented and nanotwinned Cu has been achieved. A fast bonding process occurs in 5 min under a temperature gradient between 450 and 100 °C. It is verified by grain growth across the bonded interface.

Biomechanical Comparison between Preloaded Position Screw and Lag Screw Fixations for Their Compressive Effects in a Porcine Rib Fracture Model.

Objectives:  The aim of this study was to compare the compressive effect between preloaded position screws and lag screws in fracture fixation.

Methods:  Pairs of semi-cylindrical bone fragments were created on a porcine rib model to simulate fractured bones. The compressive forces of fracture fixation generated by preloaded position screws (P group) and conventional lag screws (L group) were recorded by a film stress sensor.

Compensating additional optical power in the central zone of a multifocal contact lens forminimization of the shrinkage error of the shell mold in the injection molding process.

This study aims to develop a compensating method to minimize the shrinkage error of the shell mold (SM) in the injection molding (IM) process to obtain uniform optical power in the central optical zone of soft axial symmetric multifocal contact lenses (CL). The Z-shrinkage error along the Z axis or axial axis of the anterior SM corresponding to the anterior surface of a dry contact lens in the IM process can be minimized by optimizing IM process parameters and then by compensating for additional (Add) powers in the central zone of the original lens design. First, the shrinkage error is minimized by optimizing three levels of four IM parameters, including mold temperature, injection velocity, packing pressure, and cooling time in 18 IM simulations based on an orthogonal array L (2×3).

Optical design of soft multifocal contact lens with uniform optical power in center-distance zone with optimized NURBS.

This study aims to develop a new optical design method of soft multifocal contact lens (CLs) to obtain uniform optical power in large center-distance zone with optimized Non-Uniform Rational B-spline (NURBS). For the anterior surface profiles of CLs, the NURBS design curves are optimized to match given optical power distributions. Then, the NURBS in the center-distance zones are fitted in the corresponding spherical/aspheric curves for both data points and their centers of curvature to achieve the uniform power.

Analysis on multifocal contact lens design based on optical power distribution with NURBS.

This paper aims to develop and analyze the design method of multifocal contact lenses to obtain curvature continuity in the optical surfaces with the high addition (Add) powers by adjusting non-uniform rational B-spline (NURBS) curves. The paper has developed mathematical formulae to generate the optical power distributions in which the powers continuously change from either near or distant center to the opposite focal length in the periphery of the optical region with different change rates and Add power values. This developed method can efficiently adjust and optimize three parameters, including control points, weight, and knots of the NURBS, to be anterior optical lens surface profiles to adapt for these given power profiles.

Nanopattern fabrication by tip plowing technology on 55 nm grating with stitching image method.

An appropriate calibration positioning method is imperative to examine localized tip on nanoscale patterns for scanning probe microscopy (SPM). This paper is to develop a new nanofabrication processes for AFM tip positioning with image stitching method in tip plowing technology. Moreover, this paper adjusts the set-point amplitude (A(sp)) to develop the tip plowing technology for fabricating nanopattern on 55 nm grating gage of a silicon substrate.