• Electrical & Electronic Materials
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• v.7 no.6
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• pp.511-519
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• 1994

The effect of the deposition conditions, such as the base pressure, working pressure, sputtering power, pre-sputtering, and deposition thickness in facing targets sputtering system(FTS), on the oxidation of the TbFeCo thin films was studied by investigating the magneto-optical properties as well as oxygen analysis by the AES depth profiles. The results showed that the base pressure did not affect the magnetic properties so much, probably due to the short flight distance of the sputtered particles. At the higher sputtering power and lower working pressure with pre-sputtering the oxidation of TbFeCo thin films was decreased. As the film thickness increased the TbFeCo thin films showed the perpendicular anisotropy from in-plane anisotropy overcoming the oxidation effect at the beginning of the sputtering.

• International Journal of Automotive Technology
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• v.7 no.5
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• pp.579-584
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• 2006

Aluminum Resistance Spot Weld(Al RSW) is an enabling technology for body assembly of low mass fraction vehicles. Due to the unreliable durability of spot-welded joints, applications of Al RSW are limited. This study presents experimental investigation on the use of a post-weld cold working process to improve the fatigue strength of Al RSW. The post-weld cold working process includes special shaped indenters that are pressed or driven into the structure to induce compressive residual stresses. The mechanical properties of the post-weld cold worked Al RSW were investigated, including the experimental results of fatigue and micro-hardness tests. Comparisons of the mechanical properties and qualitative results between the as-welded RSW specimens and the post-weld cold worked RSW specimens are discussed. The post-weld cold worked Al RSW samples had an increase in both microhardness and fatigue life.

• Journal of the korean Society of Automotive Engineers
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• v.5 no.2
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• pp.31-40
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• 1983

A study was made of the effect of cold working and stabilizing temperature on the fatigue properties of Aluminum alloy 5083. The amount of cold working ranged from 14% to 35% and stabilizing temperature was 120.deg. C-160.deg. C. Rotary bending fatigue test was carried out, and it was found that 1) E specimen that had been cold worked by the cold reduction of 35% and stabilized at 160.deg. C for 2 hours was showed the most excellent fatigue limit and endurance ratio and, 2) By the results of the between crack propagation behavior and stress intensity factor, E specimen was showed the better resistance to fatigue crack growth than others.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1526-1529
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• 2005

Zinc oxide films have been actively investigated as transparent electrode materials for display. We report the effect of the working pressures on electro-optical properties of Al-doped ZnO thin films deposited by d.c. magnetron sputtering. The resistivity of the ZnO thin films was depended on atomic bombardment effect by working pressure.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.165-171
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• 2003

In a structure, many components are fastened together using bolts, nuts and rivets through drilled holes. Not only do these fastened joints enable easy assembly and dismantling, they are also able to transfer as well as to distribute loads applied onto the structures. The major drawback of such connections, however, is that the fatigue life of the components is reduced by the presence of the hole since the stress concentration around the hole is increased. In addition, the hole drilling process itself may introduce defects or roughness at the surfaces of the hole that may cause further decrease in fatigue performance of the components. For applications where fatigue loadings are important, one way to compensate the decrease in fatigue life of the components is by introduction of beneficial compressive residual stress around the hole using cold working. The material used for this research were A12024-T351 and A17050-T7451 using the primary member of aircraft. We present, In this paper, the characteristics of coldworking by evaluation of the hole expansion ratio, residual stress distribution, and fatigue properties.

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.194-200
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• 2001

In this study, the optical properties of diamond-like carbon(DLC) films, which was synthesized by 13.56 MHz rf plasma enhanced chemical vapor deposition system(PECVD), were investigated. We observed the variation of the transmittance and optical band gap with respect to deposition condition. The change of the transmittance and optical band gap of the DLC films were investigated as a function of RF power, working pressure, and additional gas. The optical band gap decreased with the increase of RF power and working pressure. We could verify the bond structures change of DLC films by observing the content of hydrogen using FT-IR spectroscopy. And the addition of hydrogen and nitrogen decreased the optical band gap by the breakage of C-H bond of DLC films during the deposition.

• Journal of the Ergonomics Society of Korea
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• v.33 no.3
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• pp.229-239
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• 2014

Objective: This research provides a guideline for working area design in the electronic industry, considering gender differences of physical characteristics. Background: Co-work in the electronic industry requires workers of various physical properties to work cohesively in the conveyor line for mass production. This stresses the need for a worker-centered design of the workplace convenient for all the workers. Method: In this research, the $6^{th}$ Size Korea (National Anthropometric Survey in Korea) report is referred to obtain the design measurements according to age and gender varieties. This information is used to provide the working area guideline concerning conveyor line workers of both genders aged 20 to 40. Results: Physical properties of workers and workplace design principles were obtained for application in the assembly, inspection, and material handling process in the electronic industry. Conclusion: Applying ergonomic design principles can provide safe and comfortable workplace for both genders. Application: This research can be fundamentally used in designing worker-centered workplaces.

• Korean Journal of Materials Research
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• v.21 no.2
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• pp.120-124
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• 2011

Silicon heterojunction solar cells have been studied by many research groups. In this work, silicon heterojunction solar cells having a simple structure of Ag/ZnO:Al/n type a-Si:H/p type c-Si/Al were fabricated. Samples were fabricated to investigate the effect of transparent conductive oxide growth conditions on the interface between ZnO:Al layer and a-Si:H layer. One sample was deposited by ZnO:Al at low working pressure. The other sample was deposited by ZnO:Al at alternating high working pressure and low working pressure. Electrical properties and chemical properties were investigated by light I-V characteristics and AES method, respectively. The light I-V characteristics showed better efficiency on sample deposited by ZnO:Al by alternating high working pressure and low working pressure. Atomic concentrations and relative oxidation states of Si, O, and Zn were analyzed by AES method. For poor efficiency samples, Si was diffused into ZnO:Al layer and O was diffused at the interface of ZnO:Al and Si. Differentiated O KLL spectra, Zn LMM spectra, and Si KLL spectra were used for interface reaction and oxidation state. According to AES spectra, sample deposited by high working pressure was effective at reducing the interface reaction and the Si diffusion. Consequently, the efficiency was improved by suppressing the SiOx formation at the interface.

• Journal of architectural history
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• v.13 no.2 s.38
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• pp.21-38
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• 2004

This study provides a descriptive and analytical account of major aspects of urban development and transformation of housing types of Italian Firenze from the 13th century to the 19th century. It is a typo-morphological depiction of urban spatial structure of the extraordinary city, Firenze, the center of Italian Renaissance. And this study has proceeded on the assumption that the evolving form of the urban structure and housing types cannot be understood without reference to the larger context of political, economic, and social life. Based on these backgrounds, the purpose of this study is threefold: to provide a comprehensive discussion of general characteristics of urban spatial structure of Firenze, and to explain the process of formation of working-class neighborhoods by constructing new city wall in later 13th century, and to discuss transformation of housing types of the working-class neighborhood with understanding the mechanism of existence of housing in the newly formed residential neighborhoods. The development of residential neighborhoods was pursued by 'planned' manner through forming square-shaped blocks, and characterized by the subdivision of larger properties into standardized building lots for the construction of houses. On the bases of documentary evidences, several ecclesiastical institutions are identified as the agents of a distinctive type of development. While the institutions did the major role for developing lands, the construction of houses was done by small scale construction agents with moderate amount of properties. The major housing type of working-class neighborhoods of Firenze has been the 'casa a schiera' characterized by the form of narrow front and long depth. The type was generalized by the newly formed middle and working-class of Firenze which grew their body very rapidly, Even though the type assumed very uniform in its fen there were many variations. And through passing time, the casa a schiera developed to be multi-family housing, and the level of variation became deepen. Eventually, transformation of housing type of Firenze was ended by appearance of the 'casa in linea', which was very similar to modern apartment in its spatial organization.

• The Journal of the Korean dental association
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• v.48 no.11
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• pp.813-818
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• 2010

Since MTA has many beneficial properties such as biocompatibility, great sealing capacity, antibacterial effects, low cytotoxicity, and stimulation of formation of mineralized tissue, it has been widely used as the material of choice in root-end filling, apexification, pulpotomy, perforation repair and so on. However, despite its favorable characteristics, MTA presents working properties which are less than ideal. The resulting cement from the mixing of powder and water is difficult to manipulate, and its setting time has been reported to be 2 h 45 min whereas the working time is <4 minutes. Additional moisture is also required to activate the setting of the cement. Moreover, according to recent studies, the physical properties of MT A may be hampered by acidic environment or blood contamination. Therefore, practitioners may have surprisingly worse results than they expected when they are not fully acquainted with the characteristics and manipulation method of MTA.