University of Seoul – TechConnect Briefs

Rapid compressive strength achievement of coal bottom ash based geopolymer by employing microwave energy

Kim H., Hong S., University of Seoul, KR

Geopolymer has been introduced as a green alternative to Portland cement to reduce CO2 from cement industry. Unlike coal fly ash, coal bottom ash has not been used widely as a source material for geopolymer [...]

Effect of elevated hot temperatures on hybrid geopolymer synthesized with coal fly and bottom ashes

Kim H., Park C.W., University of Seoul, KR

Ordinary Portland Cement (OPC) concrete has been most widely used for construction materials although the strength deterioration of OPC concrete in high temperature has been pointed out as its inherent flaw. Considering that fire is [...]

Transient Analysis on Nonlinear Model of Electrostatically Actuated Nanomechanical Switch

Kim I.K., Han D.H., Lee S.I., University of Seoul, KR

This research predicted the transient behaviors of a nano-switch with static and dynamic analysis. The nano-switch consists of a cantilevered MWCNT incorporating the electrostatic forces and intermolecular attractive and repulsive forces between the CNT and [...]

A MEMS-type Micro Sensor for Hydrogen Gas Detection

Yoon J-H, Kim B.-J., Kim J-S, Kim B.-J., Kim J-S, University of Seoul, KR

In this study, a highly sensitive hydrogen gas sensor of the multi-layer and micro-heater type was designed and fabricated using a microelectromechanical system (MEMS) process. The dimension of fabricated hydrogen gas sensor was 5 mm×4 [...]

Topology Optimization of Ultrasonic Transducers for Microsystem and IC Packaging

Kim J-M, Kim J-S, Kim J-M, Kim J-S, Lee S.I., Lim E.J., University of Seoul, KR

In this study, we introduce the method of topology optimization for piezoelectric transducers including ultrasonic tool horns for flip chip or wire bonding. Topology optimization performs an optimization with the objective function regardless of initial [...]