• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07b
• /
• pp.884-887
• /
• 2003

Strain gages were widely used transducers. Essentially a strain gage was an electric element to which an appropriate type was attached. Strain was sensed by gages and provided electrical output proportional to applied forced. This paper describes the recent development of a thick film strain gage ceramic pressure sensors. The thick film resistors as strain gage in the Wheatstone bridge were fabricated with a novel mixture of ruthenium. The thick-film technology of resistors were printed on the ceramic diaphragm back side by screen printing and cured at $850^{\circ}C$. The mechanical measurements were performed with the computer simulation results(ANSYS 5.1). The output sensitivity was 1.2mV/V, of which max. nonlinearity was less than 0.29%, hysteresis was less than 0.38%FS.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.25 no.7
• /
• pp.569-573
• /
• 2012

We investigated the speed change of the diamond spherical abrasive during the substrate surface polishing under the pad compression by using classical molecular dynamics modeling. We performed three-dimensional molecular dynamics simulations using the Morse potential functions for the copper substrate and the Tersoff potential function for the diamond abrasive. As the compressive pressure increased, the indented depth of the diamond abrasive increased and then, the speed of the diamond abrasive along the direction of the pad moving was decreased. Molecular simulation result such as the abrasive speed decreasing due to the pad pressure increasing gave important information for the chemical mechanical polishing including the mechanical removal rate with both the pad speed and the pad compressive pressure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.21 no.8
• /
• pp.766-769
• /
• 2008

Zinc oxide (ZnO) nanowires were prepared on Si substrates by a thermal evaporation method at different temperatures and $O_2$ pressure. Microstructural analysis of the obtained ZnO nanowires was performed by using transmission electron microscopy(TEM) and scanning electron microscopy(SEM). Phase analysis was done using X-ray diffraction(XRD). As the deposition temperature and oxygen pressure were increased, the diameter and length of ZnO nanowires had a tendency to increase. Based on TEM and XRD analyses, the nanowires are single crystalline in nature and consist of a single phase. According to the measurements, the ZnO nanowires grown at 1100$^{\circ}C$, Ar 50 sccm, $O_2$ 10 sccm have good properties.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.6 no.4
• /
• pp.81-85
• /
• 2007

A safety valve is used for protecting the pressure vessel and facilities by discharging the operating fluid into the valve from the accident when the pressure is over the designated value. The fluid is sulfurous acid and nitric acid. etc. in the semi-conductor assembly line. Thus the valve elements material must be acid resistance. Teflon, which is used generally as inner parts of a valve, tends to easily sticks to sliding surface by thermal expansion under high temperature. Some studies are performed to change teflon to another material and shape to have a better fluidity under the condition. The analysis of the thermal expansion is conducted by commercial FEM software to improve the problems. Boundary conditions were temperature and load in this study. From the analysis, the thermal expansion of stainless steel is verified to be lower than that of teflon under high temperature. Thus coupled teflon/stainless steel-made valve is applied to assembly line without danger due to thermal expansion.

• Fibers and Polymers
• /
• v.6 no.4
• /
• pp.336-338
• /
• 2005

This paper investigates the influence of raw material and process parameters in spinning that affect the inter fiber cohesion in yams. An instrument has been developed for measuring the minimum twist of cohesion. With regard to the raw material parameters, the influence of different cotton fiber mixings for a given count of yarn is investigated. Also the effect of spinning to varying counts for a given cotton variety is studied. With regard to the process parameters, studies have been carried out to investigate the influence of noil extraction in comber, number of draw frame passages, draft pressure in ring frame and direction of twist. Cohesion improved with increase in the noil extraction percentage in the comber. Increase in the number of draw frame passages also improved the cohesion. Draft pressure in ring frame improved the fiber cohesion in yarn up to a pressure of $2.1kg/cm^2$. Direction of twist had no effect on the cohesion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11b
• /
• pp.121-125
• /
• 2001

We study the feasibility of synthesizing Si particles using PLA method. In the previous studies, it was possible to control the size of Si nanoparticles by the He gas pressure. In this study, we fabricated sub-micron size Si particles with various shapes such as conical, hexagonal, and ring by controlling not only the ambient gas pressure but also the laser energy density. Furthermore, we found that the conical Si particles were uniform-sized and had step shape when observed from FE-SEM and AFM. The conical Si particle has the same crystal structure as the bulk single crystalline Si by the analysis of the Raman scattering. It is shown that the relationship between the laser energy density and the He gas pressure inside the chamber affects the shape of the Si particle.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11b
• /
• pp.451-454
• /
• 2001

The ionic conductivity of cubic solid solutions in the system $Y_{2}O_{3}-ZrO_{2}$ prepared by SHS was examined. Conductivity-temperature data obtained at $1000^{\circ}C$ in atmosphere of low oxygen partial pressure ($10^{-40}$ atm) for $Y_{2}O_{3}-ZrO_{2}$ cubic solid solutions indicated that these materials could be reduced, the degree of reduction being related to the measuring electric field. At low impressed fields no reduction was observed. Thus, these conductivity data give a transference number for the oxygen ion in $Y_{2}O_{3}-ZrO_{2}$ cubic solid solutions greater than 0.99.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.6
• /
• pp.527-531
• /
• 2005

Fully coherent self-assembled InAs quantum dots(QDs) grown on Si (100) substrates by atmospheric pressure metalorganic chemical vapor deposition(APMOCVD) were grown and the effect of growth conditions such as growth rate and growth time on quantum dots' morphology such as densities and sizes was investigated. InAs QDs of 30 - 80 nm in diameters with densities in the range of (0.6 - 1.7) x $10^{10}\;cm^{-2}$ were achieved on Si substrates and InAs layer was changed from 2 dimensional growth to 3 dimensional one at a nominal thickness less than 0.48 ML. This is attributed to the higher ambient pressure of APMOCVD suppressing of In segregation from the 2 dimensional InAs layer. This In segregation looked to disturb the dot formation especially when the growth rate was low so that the dots became less dense and bigger as the growth rate was lower.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.11a
• /
• pp.101-102
• /
• 2005

Cadmium telluride (CdTe) films have been prepared on Coming 7059 glass, molybdemium (Mo), and polyimide (PI) substrates by r.f. magnetron sputtering technique. The influence of the sputter pressure on the structural and optical properties of these films was evaluated. In addition, a comparison of the properties of the films deposited on different substrates was performed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.11a
• /
• pp.61-62
• /
• 2005

The present article deals with in situ post annealing of ZnO in sputtering system. The ZnO thin films were grown at low temperature of $100^{\circ}C$ and at working pressure of 15 mTorr with RF magnetron sputtering. Having been gown, ZnO thin films were annealed in situ at different temperatures, at annealing ambient pressure of 15 mTorr and in ambients of oxygen and argon respectively. Through analyses of XRDs, it is can be concluded that the crystallinity of annealed ZnO thin films becomes much better than that of as-grown ZnO thin film.