Density and viscosity are important quantities which describe the physical properties of liquid, and density is the most important thermo-physical property of hybrid nanofluids.

Many methods were proposed for density measurement of density or viscosity alone. Resonant sensors can measure density and viscosity simultaneously, so it has many applications in the fields of physical or chemical sensing in liquid.

In the measurement of liquid density and viscosity, the change of resonance parameters due to the parasitic parallel capacitance of resonator affects measurement accuracy.

In order to improve accuracy, An Nam Chol, a section head at the Faculty of Electronics, proposed a method for compensating the parasitic parallel capacitance of resonator by adding an electrode. In addition, he modeled a resonant sensor with a compensation electrode and determined the structural parameters through simulations and experiments.

He conducted some experiments to examine the effect of this method. The experimental results show that this method is valuable for compensation of parasitic parallel capacitance of an immersed resonant sensor in liquid.

You can find the details in his paper “Accuracy improvement of resonant sensor by an additional electrode in the measurement of liquid density and viscosity” in “Sensor Review” (SCI).

IGBT is a high-voltage high-power integrated circuit device and has a wide range of high-power switching applications such as mobile driving, power supply, railway transportation, industry control, etc.

The NPT-IGBT is a composite device of MOSFET and BJT. Since NPT-IGBT usually operates at high voltage and strong current, hot-carrier-induced degradation will be generated inside the device. Hot carriers with high energy will damage the oxide region of the device and the interface between silicon and silicon-dioxide, and will increase the trap charge of the interface and the oxide region.

Many researchers have described the issues on hot carriers of IGBT device, However, there have been reported a little literature that dealt with the reliability of hot carriers of NPT-IGBT.

Kim Hak Bong, a section head at the Institute of Semiconductor, analyzed the degradation mechanisms due to the hot carrier effect in NPT-IGBT through the voltage stress measurement, TCAD simulation and charge pumping measurement.

The results of the voltage stress measurement, TCAD simulation and the charge pumping measurement were consistent with the theoretical analysis.

For more information, you can refer to his paper “Analysis on Effect of Hot-Carrier-Induced Degradation of NPT-IGBT” in “Solid-State Electronics” (SCI).

The Trucklift slope hoisting system is an innovative transport technology for open-pit mines, and it considerably accelerates and cheapens transport from mines.

When a truck drives onto or off the platform at the lower loading station in the Trucklift slope hoisting system with varying profile of track, the platform motion influences the operation of the Trucklift slope hoisting system, and the configuration of inclined ropes hitched to the platform is varied.

In order to estimate the movement of platform at the lower loading station when a truck drives off or onto the platform, the movement of the truck on the platform and the lower loading station and the effect of sagged inclined ropes hitched to the platform should be considered simultaneously. The platform motion is related to not only the profile of track and parameters of truck and platform, but also the parameters of sagged inclined ropes hitched to the platform.

Kim Kwang Hyok, a researcher at the Faculty of Mining Engineering, has investigated the platform motion with consideration of sagged inclined ropes when a truck drives off or onto a platform at the lower loading station in the Trucklift slope hoisting system with varying profile of track. He proposed a system of non-linear equations to furnish an explicit solution for extensible sagged inclined ropes with edges on the inclined track, simulated platform motion by using the ADAMS software, and modeled the sagged inclined ropes hitched to the platform as a flexible body with consideration of elasticity and bend.

The simulation result shows that the displacement of platform is not considerable in comparison with the diameter of a tire, and proper design of a lower loading station enables safe movement of trucks on the platform without arresters.

You can find the details in his paper “Platform Motion at Lower Loading Station in Trucklift Slope Hoisting System with Varying Profile of Track” in “Journal of Mining and Environment” (SCI).