• International Journal of Contents
• /
• v.16 no.3
• /
• pp.45-50
• /
• 2020

Occupational therapists (OTs) interface patients much longer than other healthcare workers and, thus, are likely to experience a high level of stress because of work, physical fatigue, lack of professional knowledge and skills, and problematic relationships with patients, etc. This study examined the quality of the lives of OTs and the workplace which is an influential factor. This study recruited 200 OTs and used a professional quality of life scale. We found that, only 27.0% experience high levels of compassion satisfaction (CS) and 80.5% and 74.5% experience high or average levels of burnout (BO) and secondary traumatic stress (STS) of compassion fatigue (CF), respectively. We discovered that CS was higher in temporary employees; and CF was higher in females, subjects in their 30s; and those working at general hospitals. Also, BO was higher in those with one to five years of clinical experience and regular employees. Last, STS was higher in the group without stable income. This study verified that clinical experience is a critical factor that reduces BO, and excessive workload outside of treatment lowers the professional quality of life. This suggests that work environment and regulations related to OTs must be improved to increase CS and reduce CF.

• Journal of Powder Materials
• /
• v.9 no.1
• /
• pp.19-24
• /
• 2002

This paper reports the results of an investigation into the effect of Cu additions upon the nano-crystallization behaviour of an Al-Y-Ni alloy. 1 at.% Cu was added to a base alloy of Al/sub 88/Y₄Ni/sub 8/ either by substitution for Al to form Al/sub 87/Y₄Ni/sub 8/Cu₁, or by substitution for Ni to form Al/sub 88/Y₄Ni/sub 7/Cu₁. Consistent with previous findings in the literature, the substitution of Cu for Al was found to increase the thermal stability of the amorphous phase whereas the substitution of Cu for Ni was found to decrease its thermal stability. Comparing the microstructures of these alloys after heat treatment to produce equivalent volume fractions of Al nanocrystals showed average grain sizes of 14 nm, 12 nm and 9 nm for the alloys Al/sub 88/Y₄Ni/sub 8/, Al/sub 87/Y₄Ni/sub 8/Cu₁respectively. The effect of Cu in refining the size of the nanocrystals was attributed to enhanced nucleation increasing the number density of the nanocrystals, rather than diffusion limited or interface limited growth.

• Tribology and Lubricants
• /
• v.25 no.4
• /
• pp.225-230
• /
• 2009

Seals are very useful machine components in protection of leakage of lubricant or working fluid, and incoming of debris from outside. Various elastomer are widely used as sealing materials and the shaft surfaces are generally coated with high hardness material after heat treatment. It is generally known that the foreign debris and wear particles get stuck into sealing surface, the steel shaft surface can be damaged and worn by mainly abrasive wear. In this paper, using MARC, contact analysis are conducted to show the hard coated steel shaft surface can be fatigue failed by very small elastic particle intervened between seal and steel surface. Variations of contact and von-Mises stress distributions and contact half-widths with interference and coating thickness are presented. The maximum von-Mises stress occurs always in the coating layer or between coated layer/substrate interface. Therefore the coated sealing surface can be fatigued and then failed by very small particles. The results can be used in design of sealing surface and further studies are required.

• Journal of Surface Science and Engineering
• /
• v.49 no.5
• /
• pp.467-471
• /
• 2016

In order to investigate the Na gettering, PSG/$SiO_2$/Al-1%Si multilevel thin films were fabricated. DC magnetron sputter techniques and APCVD (atmosphere pressure chemical vapor deposition) were utilized for the deposition of Al-1%Si thin films and PSG/$SiO_2$ passivations, respectively. Heat treatment was carried out at $300^{\circ}C$ for 5 h in air. SIMS (secondary ion mass spectrometry) depth profiling and XPS (X-ray Photoelectron Spectroscopy) analysis were used to determine the distribution and binding energies of Na, Al, Si, O, P and other elements throughout the PSG/$SiO_2$/Al-1%Si multilevel thin films. Na peaks were mainly observed at the the PSG/$SiO_2$ interface and at the $SiO_2$/Al-1%Si interfaces. Na impurity gettering in PSG/$SiO_2$/Al-1%Si multilevel thin films is considered to be caused by a segregation type of gettering. The chemical state of Si and O elements in PSG passivation appears to be $SiO_2$.

• Journal of Surface Science and Engineering
• /
• v.51 no.1
• /
• pp.34-39
• /
• 2018

Steel crucible used for molten Al has a problem of very limited lifetime because of the interaction between Fe and molten Al. This study was performed to improve the lifetime of steel crucible for molten Al by coating metallic Al and by further anodizing treatment to form thick and uniform anodic oxide films. The lifetime of the steel crucible was improved slightly by Al coating from 30 to 40 hours by metallic Al coating and largely to 120 hours by coating the surface with anodic oxide film. The improved lifetime was attributed to blocking of the reaction between Fe and molten Al with the help of anodic oxide layer with more than 20 um thickness on the crucible surface. The failure of the steel crucible arises from the formation of intermetallic compounds and pores at the steel/Al interface.

• Journal of the Korean Ceramic Society
• /
• v.55 no.4
• /
• pp.358-363
• /
• 2018

To improve the polarization property of cathodes, which is the main factor limiting the performance of protonic ceramic fuel cells (PCFCs), $K_2NiF_4-type$ $Pr_2NiO_{4+{\delta}}$, which is expected to exhibit a triple conducting property (proton, oxygen ion, and hole conductions) was applied to PCFCs and its properties were investigated. Low-temperature microwave heat-treatment was used to achieve both sufficient interface adhesion between the electrolyte and the cathode layers and suppression of the secondary phase formation due to migration of elements such as barium and cerium. Through this fabrication method, a high performance of $0.82W{\cdot}cm^{-2}$ and low ohmic resistance of $0.06{\Omega}{\cdot}cm^2$ were obtained in an $Ni-BaCe_{0.55}Zr_{0.3}Y_{0.15}O_{3-{\delta}}$ | $BaCe_{0.55}Zr_{0.3}Y_{0.15}O_{3-{\delta}}$ | $Pr_2NiO_{4+{\delta}}$ single cell at $650^{\circ}C$. This result verifies that the $K_2NiF_{4+{\delta}}-type$ cathode shows good chemical compatibility which, in turn, will make it a potent candidate as a PCFC cathode.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.11
• /
• pp.1044-1049
• /
• 2006

We reported on characteristics of the fluorescent OLED fabricated on commercial ITO/glass and BCS grown IZO/glass substrate, respectively. The amorphous IZO anode film grown by box cathode sputtering(BCS) exhibited similar electrical and optical characteristics to commercial ITO anode even though it was deposited at room temperature. In addition, the amorphous IZO anode showed higher workfunction (5.2 eV) than that of the commercial ITO anode (5.0 eV) after ozone treatment for 10 min. Furthermore, fluorescent OLED fabricated on amorphous IZO anode film showed improved current-voltage-luminance characteristics, external quantum efficiency and power efficiency en contrast with fluorescent OLED fabricated on commercial ITO anode film. It was thought that smooth surface and high workfunction of amorphous IZO anode lead to more efficient hole injection by reduction of interface barrier height between anode and organic layers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.8
• /
• pp.701-706
• /
• 2006

In addition to its similarity to genuine diamond film, diamond-like carbon (DLC) film has many advantages, including its wide band gap and variable refractive index. In this study, DLC films were prepared by the RF PECVD (Plasma Enhanced Chemical Vapor Deposition) method on silicon substrates using methane $(CH_4)$ and hydrogen $(H_2)$ gas. We examined the effects of the post annealing temperature on the structural variation of the DLC films. The films were annealed at temperatures ranging from 300 to $900^{\circ}C$ in steps of $200^{\circ}C$ using RTA equipment in nitrogen ambient. The thickness of the film and interface between film and substrate were observed by surface profiler, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), respectively. Raman and X-ray photoelectron spectroscopy (XPS) analysis showed that DLC films were graphitized ($I_D/I_G$, G-peak position and $sp^2/sp^3$ increased) ratio at higher annealing temperature. The variation of surface as a function of annealing treatment was verified by a AFM and contact angle method.

• Journal of Magnetics
• /
• v.10 no.2
• /
• pp.66-70
• /
• 2005

The junction properties between the ferromagnet (FM) and two-dimensional electron gas (2DEG) system are crucial to develop spin electronic devices. Two types of 2DEG layer, InAs and GaAs channel heterostructures, are fabricated to compare the junction properties of the two systems. InAs-based 2DEG layer with low trans-mission barrier contacts FM and shows ohmic behavior. GaAs-based 2DEG layer with $Al_2O_3$ tunneling layer is also prepared. During heat treatment at the furnace, arsenic gas was evaporated and top AlAs layer was converted to aluminum oxide layer. This new method of forming spin injection barrier on 2DEG system is very efficient to obtain tunneling behavior. In the potentiometric measurement, spin-orbit coupling of 2DEG layer is observed in the interface between FM and InAs channel 2DEG layers, which proves the efficient junction property of spin injection barrier.

• Korean Journal of Materials Research
• /
• v.19 no.3
• /
• pp.119-124
• /
• 2009

In the microelectronics packaging industry, the adhesion strength between Cu and polyimide and the thermal stability are very important factors, as they influence the performance and reliability of the device. The three different buffer layers of Cr, 50%Cr-50%Ni, and Ni were adopted in a Cu/buffer layer/polyimide system and compared in terms of their adhesion strength and thermal stability at a temperature of $300^{\circ}C$ for 24hrs. A 90-degree peel test and XPS analysis revealed that both the peel strength and thermal stability decreased in the order of the Cr, 50%Cr-50%Ni and Ni buffer layer. The XPS analysis revealed that Cu can diffuse through the thin Ni buffer layer ($200{\AA}$), resulting in a decrease in the adhesion strength when the Cu/buffer layer/polyimide multilayer is heat-treated at a temperature of $300^{\circ}C$ for 24hrs. In contrast, Cu did not diffuse through the Cr buffer layer under the same heat-treatment conditions.