A Novel Nanocomposite with Photo-Polymerization for Wafer Level Application

©2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or distribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.A novel nanocomposite photo-curable material which can act both as a photoresist and a stress redistribution layer applied on the wafer level was synthesized and studied. In the experiments, 20-nm silica fillers were modified by a silane coupling agent through a hydrolysis and condensation reaction and then incorporated into the epoxy matrix. A photo-sensitive initiator was added into the formulation which can release cations after ultraviolet exposure and initiate the epoxy crosslinking reaction. The photo-crosslinking reaction of the epoxy made it a negative tone photoresist. The curing reaction of the nanocomposites was monitored by a differential scanning calorimeter with the photo-calorimetric accessory. The thermal mechanical properties of photo-cured nanocomposites thin film were also measured. It was found that the moduli change of the nanocomposites as the filler loading increasing did not follow the Mori–Tanaka model, which indicated that the nanocomposite was not a simple two-phase structure as the composite with micron size filler. The addition of nano-sized silica fillers reduced the thermal expansion and improved the stiffness of the epoxy, with only a minimal effect on the optical transparency of the epoxy, which facilitated the complete photo reaction in the epoxy

Study on vibration isolation performance of elastic coupling under longitudinal excitation

According to longitudinal vibration differential equations of ship propulsion shafting, deduced transfer matrix of propeller, uniform shaft segment and thrust bearing which composed propulsion shafting. Given longitudinal vibration natural frequency of propulsion shafting using the transfer matrix solver, and compared with finite element simulation results to verify the accuracy of the finite element model. Then analysis the effect of elastic coupling axial stiffness on modal frequencies of shafting longitudinal vibration and vibration isolation performance through simulation. Results show that: elastic coupling can effectively isolate the propulsion shafting vibration transmitted to the propulsion motor; when the axial stiffness ratio of thrust bearing and elastic coupling is greater than 50, the impact of elastic coupling axial stiffness on longitudinal vibration natural frequency of propulsion shafting and acceleration level and axial displacement of thrust bearing is very small; when the stiffness ratio is greater than 100, the elastic coupling can achieve better vibration isolation effect

Geometric Power Control for Time-Switching Energy-Harvesting Two-User Interference Channel

© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. This paper studies the optimization of power control for the two-user interference channel in which the terminals are time-switched between the communication and energy-harvesting phases. The objective is to maximize the sum-rate, subject to the minimum data and harvested energy constraints at the receivers, assuming a fixed time-switching coefficient. Our key contribution is a geometric approach that analyzes the feasible region governed by the constraints, which gives rise to the optimal power control solution. We assume that perfect channel state information (CSI) is available at both transmitters to determine the solution