• Journal of Sensor Science and Technology
• /
• v.28 no.3
• /
• pp.198-204
• /
• 2019

In this study, we propose a wearable force sensor using 3D printed mold and liquid metal. Liquid metal, such as Galinstan, is one of the promising functional materials in stretchable electronics known for its intrinsic mechanical and electronic properties. The proposed soft force sensor measures the external force by the resistance change caused by the cross-sectional area change. Fused deposition modeling-based 3D printing is a simple and cost-effective fabrication of resilient elastomers using liquid metal. Using a 3D printed microchannel mold, 3D multichannel Galinstan microchannels were fabricated with a serpentine structure for signal stability because it is important to maintain the sensitivity of the sensor even in various mechanical deformations. We performed various electro-mechanical tests for performance characterization and verified the signal stability while stretching and bending. The proposed sensor exhibited good signal stability under 100% longitudinal strain, and the resistance change ranged within 5% of the initial value. We attached the proposed sensor on the finger joint and evaluated the signal change during various finger movements and the application of external forces.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2004.06a
• /
• pp.337-337
• /
• 2004

As one of researches for the P ＆ T purposes, a basic experiment on the recovery of actinide elements from the mixture with rare earth elements by means of electrorefining using a liquid cadmium cathode in the LiCl-KC1 eutectic melt was carried out. In order to examine the behaviors of electrodeposition of metal ions on a liquid electrode, recovery experiments of rare earth metals resulting from forming electrodeposits were performed by a galvanostatic electrolysis method at various current densities. A cyclic voltammetric technique was applied to determine reduction-oxidation potential of each metal element in the melt and to detect the changes of the multi component melt composition for on-line monitoring. Also, a collaboration study with RIAR was completed to test the preliminary feasibility on a recovery of actinide elements from the mixture with rare earth elements using a liquid cadmium cathode and actinide metals. Experimental results showed that the ratio of actinides to rare earths, 9: 0.5∼1 led to the rare earth content of about 5∼10 wt% in the deposit.

• Journal of Powder Materials
• /
• v.9 no.3
• /
• pp.189-198
• /
• 2002

In this work, transient liquid phase (TLP) bonding of Ni-Cr heat resisted cast alloy (HP) was investigated. And also the behaviors of the solid particles distributed in the interlayer during TLP bonding were investigated. The MBF-60 and solid particles (Ni, Fe, and $Al_2O_3$ powders respectively) added MBF-60 which will be a liquid phase coexisting with solid particles at the bonding temperature were used as insert metal. The effective and sound bonding was possible by spark plasma sinter-bonding due to the differences of electric resistance between base metal and liquid insert layer which creates high temperature region. During the isothermal solidification, $Al_2O_3$ particles and solid particles of liquid phase sintered insert metal have shown no growth, while Ni and Fe particles grow rapidly. In this TLP bonding using the MBF-60 and distributed Fe, Ni particles as insert materials, the whole isothermal solidification process was dominated by the growth rate of the solid particles distributed in the interlayer.

• Journal of the Microelectronics and Packaging Society
• /
• v.23 no.2
• /
• pp.73-78
• /
• 2016

An increase in the transistor density of integrated circuit devices leads to a very high increase in heat dissipation density, which causes a long-term reliability and various thermal problems in microelectronics. In this study, liquid cooling method was investigated using straight microchannels with various metal bumps. Microchannels were fabricated on Si wafer using deep reactive ion etching (DRIE), and Ag, Cu, or Cr/Au/Cu metal bumps were placed on Si wafer by a screen printing method. The surface temperature of liquid cooling structures with various metal bumps was measured by infrared (IR) microscopy. For liquid cooling with Cr/Au/Cu bumps, the surface temperature difference before and after liquid cooling was $45.2^{\circ}C$ and the power density drop was $2.8W/cm^2$ at $200^{\circ}C$ heating temperature.

• Bulletin of the Korean Chemical Society
• /
• v.21 no.10
• /
• pp.989-994
• /
• 2000

• Nuclear Engineering and Technology
• /
• v.47 no.5
• /
• pp.588-595
• /
• 2015

This study presents an effective method for additional recovery of residual actinides in liquid electrodes after the electrowinning process of pyroprocessing. The major distinctive feature of this method is a reactor with multiple reaction cells separated by partition walls in order to improve the recovery yield, thereby using the interelement difference in diffusion coefficients within the liquid electrode and controlling the selectivity and purity of element recovery. Through an example of numerical simulation of the diffusion scenarios of individual elements, we verified that the proposed method could effectively separate the actinides (U and Pu) and rare-earth elements contained in liquid cadmium. We performed a five-step consecutive recovery process using a simplified conceptual reaction cell and recovered 58% of the initial amount of actinides (U + Pu) in high purity (${\geq}99%$).

• Design & Manufacturing
• /
• v.15 no.2
• /
• pp.30-35
• /
• 2021

The casting method uses a mold to solidify a liquid metal to make a solid metal. Since it uses a liquid metal with the least deformation resistance, it has the characteristic that it can easily manufacture even a complex shape. However, the process of solidifying a liquid metal into a solid metal inevitably involves a volume change and contains internal defects such as shrinkage holes. Therefore, in the design of the casting plan, an excess volume called a pressurization compensates for the volume shrinkage. in the product, and it induces the shrinkage hole defects to occur in parts other than the product1). In this study, casting analysis was performed using casting analysis software (anycasting) in order to optimize the design of the tilting gravity casting method for automobile brackets. In particular, the filling and solidification analysis according to the shape and volume of the pressurized metal was conducted, and applied to the actual product to study the effect of the pressurized metal on the shrinkage defect. Through this study, it is possible to understand the effect of the pressure metal on shrinkage defects in the actual product and propose a design of the pressure metal that improves reliability and productivity.

• Archives of Pharmacal Research
• /
• v.9 no.4
• /
• pp.211-214
• /
• 1986

A simultaneous determination method of alkaline earth metals was attempted with the conventional high performance liquid chromatographic system. Four cations, namely, magnesium, calcium, strontium and barium ion, were injected directly as aqueous solution into an eluent containing copper chloride solution and and were successfully separated and determined on a separating column (Zipax SCX, 4.6 mm i.d. ${\times}25$ cm length, Du Pont, USA) by using a variable wavelength UV detector. The linear calibration curves were obtianed in the range from $1.0{\times}10^{-4}M$ to $5.0{\times}10^{-4}M$ and the correlation coefficient of the calibration curve for each metal of magnesium and calcium in tap water. Alkaline earth metals were determined with the conventional high performance liquid chromatographic system.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.3110-3115
• /
• 2007

The effect of Lorentz force(Electromagnetic force) on the liquid metal flow has been investigated. The flow velocity has been calculated by treating the Lorentz force as a source term in the Navier-Stokes equation. The liquid metal flow in the rectangular duct of an electromagnetic pump was analyzed with the Lorentz force varied.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.10
• /
• pp.1271-1278
• /
• 2004

In order to measure non-intrusively velocity profile in liquid metal flow, a modified electromagnetic flowmeter was designed, which was based on electromagnetic tomography technique. Under the assumption that flow is fully-developed, axisymmetric and rectilinear, the velocity profile was reconstructed after the flowmeter equation, the first kind of Fredholm integration equation, was linearized. In reconstruction process Tikhonov regularization method with regularization parameter was used. The reconstructed velocity profile had the nearly same as turbulent flow profile which was approximately represented as log law. In addition, flowmeter output fur a fixed magnet rotation angle was linearly proportional to flow rate. When magnet rotation angle was 54$^{\circ}$, axisymmetric weight function was nearly uniform so that the flowmeter gives a constant signal for any fully-developed, axisymmetric and rectilinear profile with a constant flow rate.